Importance of Community Participation in Sustainable ...

Journal of Environmental Science and Engineering B Volume 1, Number 7, July 2012 (Serial Number 7)

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Publication Information: Journal of Environmental Science and Engineering B (formerly parts of Journal of Environmental Science and Engineering ISSN 1934-8932, USA) is published monthly in hard copy (ISSN 2162-5263) and online (ISSN 2162-5271) by David Publishing Company located at 9460 Telstar Ave Suite 5, EL Monte, CA 91731, USA. Aims and Scope: Journal of Environmental Science and Engineering B, a monthly professional academic journal, covers all sorts of researches on environmental management and assessment, environmental monitoring, atmospheric environment, aquatic environment and municipal solid waste, etc.. Editorial Board Members: Dr. Bishnu Rajupreti (Nepal), Prof. Jianhua Wang (China), Prof. Mankolli Hysen (Albania), Dr. Jungkon Kim (South Korea), Prof. Samira Ibrahim Korfali (Lebanon), Prof. Pradeep K. Naik (Bahrain), Dr. Ricardo García Mira (Spain), Dr. Leucci Giovanni (Italy), Prof. Konstantinos C. Makris (Gonia Athinon & Nikou Xiouta), Prof. Kihong Park (South Korea), Prof. Mukesh Sharma (India), Dr. Hesham Gehad Mohamed Ibrahim (Palestine), Dr. Jyoti Prakash Maity (India), Dr. Giuseppe Mascolo (Italy), Dr. Satinder Kaur Brar (Canada), Dr. Jo-Ming Tseng (Taiwan), Associate Prof. Muntean Edward Ioan (Romania). Manuscripts and correspondence are invited for publication. You can submit your papers via Web Submission, or E-mail to [email protected], [email protected] or [email protected]. Submission guidelines and Web Submission system are available at http://www.davidpublishing.com, http://www.davidpublishing.org. Editorial Office: 9460 Telstar Ave Suite 5, EL Monte, CA 91731, USA Tel: 1-323-984-7526, 323-410-1082 Fax: 1-323-984-7374 E-mail: [email protected]; [email protected]; [email protected] Copyright©2012 by David Publishing Company and individual contributors. All rights reserved. David Publishing Company holds the exclusive copyright of all the contents of this journal. In accordance with the international convention, no part of this journal may be reproduced or transmitted by any media or publishing organs (including various websites) without the written permission of the copyright holder. Otherwise, any conduct would be considered as the violation of the copyright. The contents of this journal are available for any citation. However, all the citations should be clearly indicated with the title of this journal, serial number and the name of the author. Abstracted/Indexed in: CAS (Chemical Abstracts Service) Database of EBSCO, Massachusetts, USA Chinese Database of CEPS, Airiti Inc. & OCLC Cambridge Science Abstracts (CSA) Ulrich’s Periodicals Directory Chinese Scientific Journals Database, VIP Corporation, Chongqing, China Summon Serials Solutions Subscription Information: Price (per year): Print $600, Online $480 Print and Online $800 David Publishing Company 9460 Telstar Ave Suite 5, EL Monte, CA 91731, USA Tel: 1-323-984-7526; 323-410-1082; Fax: 1-323-984-7374 E-mail: [email protected]

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Journal of Environmental Science and Engineering B Volume 1, Number 7, July 2012 (Serial Number 7)

Contents Environmental Ecology 827

Performance of Tree Species Growing on Tailings Dam Soils in Zambia: A Basis for Selection of Species for Re-vegetating Tailings Dams Martin K. Kambing’a and Stephen Syampungani

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Importance of Community Participation in Sustainable Utilization of Wetlands: Case of Chebvute in Zvishavane District of Zimbabwe Thomas Marambanyika, Cuthbert Mutsiwegota and Kudakwashe Collins Ralph Muringaniza

Environmental Management and Assessment 845

Management of Solid Waste in a Market: Case Study of Bodija Market, Ibadan, Nigeria Omolara Lade, Oluwole Agbede and Oluseun Ilori

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Vulnerability to Desertification in Lebanon Based on Geo-information and Socioeconomic Conditions Talal Darwish, Pandi Zdruli, Ramy Saliba, Mohamad Awad, Amin Shaban and Ghaleb Faour

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Construction and Demolition Debris Management for Sustainable Reconstruction after Disasters: Italian Case Studies Carla Furcas and Ginevra Balletto

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Dodging the Potholes: The Spatio-Distribution and Socio-Economic Impacts of Potholes in the Residential Areas of Gweru, Zimbabwe Mutekwa Timothy, Matsa Mark and Kanyati Kudzanai

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The Relationship between Meteorological Urban/Suburban Areas of Brazilian Cities

Variables

and

Clearness

Index

for

Four

Francisco José Duarte Gomes, Luciana Sanches, Marcelo de Carvalho Alves, Marta Cristina de Jesus Albuquerque Nogueira and José de Souza Nogueira

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Development of a Disaggregated Hybrid Model for Life Cycle Assessment and De-manufacturing Spivak Alexander and Matthew Franchetti

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Assessment of Soil Erosion in Mountain Watershed Ecosystems in Tirana-Region Entela Çobani and Oltion Marko

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The Impact of the Ghana’s Oil Discovery on Land Investment and Its Implications in the People, Agriculture and the Environment (Case Study: Cape Three Points, Ghana) Peter Paa-Kofi Yalley, Chris Atanga, Joe Fredrick Cobbinah and Philip Kwaw

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Influence of Rainfall, Discharge, Wave and Alongshore Transport on Microbiological Pollution in Southern California Coastal Beaches Seung Yeon Choi and Youngsul Jeong

Journal of Environmental Science and Engineering B 1 (2012) 827-831 Formerly part of Journal of Environmental Science and Engineering, ISSN 1934-8932

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Performance of Tree Species Growing on Tailings Dam Soils in Zambia: A Basis for Selection of Species for Re-vegetating Tailings Dams Martin K. Kambing’a and Stephen Syampungani Department of Forest Resource Management, School of Natural Resources, The Copperbelt University, Kitwe 21692, Zambia Received: April 23, 2012 / Accepted: June 25, 2012 / Published: July 20, 2012. Abstract: To facilitate the development of the basis for the selection of plants for re-vegetating tailings in Zambia, an as sessment of the performance of tree species growing on tailings dams was conducted. The performance of species was determined in terms of relative density, frequency and importance value for each species. The study reveals variations in performance of species; for example in terms of importance values, Acacia polyacantha (33.5%), Toona ciliata (21.4%), Acacia sieberana (9.9%), Bauhinia thonningii (9.1%) and Peltophorum africanum (8.3%) were the most dominant species. The dominance of these species on tailings dams demonstrates tolerance to tailings dams conditions. The study recommends that emphasis must be placed on these species in re-vegetating tailings dams. Key words: Tailings, tree performance, re-vegetation, importance values.

1. Introduction Most of the abandoned mine tailing sites in Copperbelt remain un-vegetated for extended periods of time and are subject to eolian dispersion and water erosion. As the viability of mines begins to decline, mine closures and the liabilities associated with mine closure become more and more eminent. One of the liabilities is the re-vegetation of areas with tailings. The use of vegetation to stabilize metal mine wastes impacted areas has been attempted in many parts of the world with both failures and successes [1-3]. Other studies [4, 5] have reported specific plant species with a high degree of resistance to metal toxicity. Metal tolerance tends to evolve in some members of common species found growing on mineralized soils [6]. These individuals may adapt internal mechanisms which may either limit the uptake of metal ions or

detoxify these ions within their tissues [7]. The use of plants through either natural or artificial re-vegetation in stabilizing tailings dams have been employed in the Zambian Copperbelt region. However, no studies have been made to determine the performance of these species on tailings dams. Such information would provide an understanding on how individual species develop on tailings sites which will in turn guide the species selection for re-vegetation of tailings dams. This study, therefore, aimed at developing an understanding of the performance of various tree species growing on tailings dam soils to guide species selection for use in rehabilitating tailings dams in Copperbelt. The key questions were: (1) what plant species grow on tailings? (2) What are the diameters of individuals of each plant species growing on tailings dams?

2. Materials and Methods Corresponding author: Martin K. Kambing’a, B.Sc., forester, main research fields: environmental management, science education, biodiversity and natural resource management. E-mail: [email protected].

2.1 Study Area The study was conducted on tailings dam No. 25 in

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Performance of Tree Species Growing on Tailings Dam Soils in Zambia: A Basis for Selection of Species for Re-vegetating Tailings Dams

Nkana, east of Kitwe District, Zambia. The tailings dam which covers an area of about 105 ha was established between 1941 and 1946. It contains about 27 metrics of tonnes of tailings, which fall into either Sulphide ore or Oxide ore tails [8]. The site is of low nutrients and water retention capacity. 2.2 Data Collection Five transects at 200 m from each other were established across the tailings dam. In each transect a number of 30 m diameter circular sample plots were established depending on the length of the transect. The sampling technique gave 20 circular plots. In each sample plot, both the heights and diameters were measured using the hypsometer and the calliper for each species. 2.3 Data Analysis The collected information was used to determine: species list, ecological density, abundance, frequency, relative dominance, relative density, relative frequency, size class distribution for trees, and importance value of tree species. The importance value is defined as follows: For plants of ≥ 5 cm Dbh IV = (RF + RD + RBA)/3 where: SP × 100 TP SR × 100 RD = NS BAS × 100 RBA = TBa RF =

where: IV = Importance value; RF = Relative frequency; RD = Relative density; RBA = Relative basal area; SP = Number of plots in which species is present; SR = Number of stems of species recorded; BAS = Basal area of a species in a community; NS = Number of stems recorded for all species; TP = Total number of plots recorded;

TBa = Total basal area of all species in the community. For plants of < 5 cm Dbh IV = (RF + RD)/2 Additionally, graphs showing size class profiles were developed from diameter data using Excel 2007 to define the development pattern at both population and stand levels.

3. Results 3.1 Species Diversity The total number of species identified from the study site was 21. The most dominant species in terms of importance values for stems greater than 5 cm Dbh (%) were Acacia polyacantha (33.48), Toona ciliata (21.4), Acacia sieberana (9.94), Bauhinia thonningii (9.05), and Peltophorum africanum (8.25), while other species had importance values < 3 (Table 1). Trees with Dbh < 5 cm were dominated by A. polyacantha, Psidium guajava, B. thonningii, and P. africanum. A. polyacantha, P. thonningii and P. africanum were also found to dominate this category (Table 2). The mean basal area was 9.38 ± 1.01 (m2/ha) and the density (trees/ha) was 22.6 ± 20.14 for species with Dbh ≥ 5 cm while stems with Dbh < 5 cm the mean total density was 13.3 ± 13.11 stems/ha. 3.2 Size Class Distribution 3.2.1 Size Class Distribution at Stand Level for Stems with Dbh ≥ 5 cm Fig. 1 shows the stem size distribution for stems Dbh ≥ 5 cm. It shows a gradual decrease in stem frequency from the lowest class (5-8 cm) to the highest class (> 48 cm). This is an example of an inverse J-shaped size class structure. 3.2.2 Size Class Distribution at Stand Level for Stems with Dbh < 5 cm The diameter distribution for stems less than 5 cm Dbh shows that classes of 1-1.9 m and 2-4.9 m had the highest number of stems as compared to the other classes (Fig. 2).


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Table 1 Importance values for species with Dbh ≥ 5 cm. Botanical name Acacia polyacantha Toona ciliate Acacia sieberana Bauhinia thonningii Peltophorum africanum Ficus ingens Gmelina arborea Parkia filicoidea Monotes katangensis Isoberlinia angolensis Oldefielda dactylophylla Rhus longipes Psidium guajava Acacia erioloba Albizia amara Mangifera indica Combretum molle Azanza garckenia Brachstegia stipulate Syzygium guineense

Relative frequency (%) 19.74 19.74 7.89 14.47 7.89 2.63 2.63 2.63 2.63 2.63 2.63 2.63 2.63 1.32 1.32 1.32 1.32 1.32 1.32 1.32

Relative density (%) 38.64 18.54 10.18 8.08 9.14 3.13 0.52 1.57 0.78 1.04 0.78 0.78 0.01 2.35 0.26 1.04 0.78 0.78 0.78 0.01

Relative dominance (%) Importance value (%) 42.06 33.48 25.93 21.4 13.82 9.94 3.53 9.05 6.66 8.25 1.69 2.48 1.74 2.24 0.54 1.58 0.57 1.42 0.68 1.37 0.27 1.32 0.11 1.18 0.03 1.06 0.97 1.02 0.57 0.89 0.44 0.85 0.2 0.77 0.1 0.65 0.04 0.54 0.02 0.53

Table 2 Importance values for species with Dbh < 5 cm. Botanical name Acacia polyacantha Psidium guajava Bauhinia thonningii Peltophorum africanum Acacia sieberana Syzygium guineense Toona ciliate Oldefielda dactylophylla Rhus longipes Lannea discolour Gmelina arborea

Relative frequency (%) 20 16.67 13.33 13.33 6.67 3.33 6.67 6.67 6.67 3.33 3.33

Fig. 1 Stand level size class distribution of Dbh ≥ 5 cm (stems/ha).

Relative density (%) 17.11 15.79 11.84 10.53 7.28 6.92 6.92 6.92 5.96 4.96 2.33

Importance value (%) 18.55 16.23 12.59 11.93 7.28 6.93 6.62 6.62 5.96 4.96 2.32

Fig. 2 Stand level size class distribution of Dbh < 5 cm (stems/ha).

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3.2.3 Size Class Distribution for Dominant Species with Dbh ≥ 5 cm Two distinct size class profiles were observed for dominant species namely: inverse J shaped structure (Acacia polyacantha) and bell-shaped size structure for Toona ciliata and Acacia sieberana (Fig. 3). 3.2.4 Size Class Distribution for Dominant Species with Dbh < 5 cm The analysis of size class distribution for dominant species with Dbh < 5 cm showed variation in stem frequency from class to class for each species (Fig. 4). However, all the species had the highest stem frequency in 1.0-1.9 m class followed by 2.0-4.9 m class. None of the species had stems in < 1 m class (Fig. 4).

Fig. 3 Size class distribution for three dominant species with Dbh ≥ 5 cm.

4. Discussion 4.1 Species Diversity The results of the study reflect the effect of tailings soils on the composition and structure of vegetation on a tailings dam in Zambia. It shows that the species diversity is generally high (21). The high number of species occurring on tailings dam is an indication of the number of species capable of tolerating such environment. However, the vigour and performance of these species vary. Each of these species responds differently to the tailings dam environment. Out of 21 species identified, only five species dominated the site in terms of importance values (Table 1). Such species, also called the pioneer species, have very low nutrient requirements and over time they are capable of improving the soil environment to a level at which other species can live and these plants have evolved characteristics which fit that particular ecological niche [6]. They tend to adapt to toxic environments by either developing internal mechanisms that limit uptake of the metals or detoxifying them within their tissues [8]. Reports of plant species surviving on tailings dam soils have also been made in other parts of the world: Sesbania species in Australia [9], Acacia species in New Zealand [10], and many other species in China [9]. Species such as Acacia species are

Fig. 4 Regeneration size class distribution for dominant species Dbh < 5 cm.

considered to be invasive as they have potential to survive and adapt to varying environments [10]. They are of wider ecological amplitude. This may explain why A. polyacantha dominated the study site. Additionally, Acacia species are leguminous plants capable of fixing atmospheric nitrogen into the soil and therefore tend to improve the nutrient status of the soils with time. 4.2 Size Class Distribution at Both Stand and Population Levels The size class profile gives different size structure


profiles for different diameter categories, Dbh ≥ 5 cm and Dbh < 5 cm at both stand and population levels. At stand level, for stems with Dbh ≥ 5 cm, the vegetation has a classic reverse J-distribution in which the number of trees declines with increasing size classes (Fig. 1). It is indicative of the population of species that are tolerant of the conditions prevailing in a stand, i.e. harsh tailings dam conditions. While for stems with Dbh < 5 cm, it represents regeneration exhibiting a bell shaped distribution (Fig. 4). The bell-shaped size class profile exhibited by stems with Dbh < 5 cm depicts the characteristic population which experience sporadic or irregular seedling establishment. The irregular seedling establishment may be attributed to harsh environmental conditions such as inadequate moisture and nutrients. At individual population levels, the inverse J-shaped size class profile exhibited by A. polyacantha indicates the ability of this species to tolerate this harsh environment while the bell shape size class profile exhibited by T. ciliata and A. sieberana (Fig. 3) indicates that these species experience irregular seedlings/plant establishment due to harsh conditions. The high numbers of plants in lower class for A. polyacantha is an indication of adequate regeneration and population maintenance for classes above 5 cm Dbh. However, the structure exhibited by class < 5 cm Dbh classes is indicative of the fact that the young seedlings are heavily restricted to develop into the size categories of > 1 m height class.

5. Conclusion The study has provided useful information on the performance of plant species at both stand and population levels on tailings sites. It has also shown the gap in terms of plant development for > 1 m height class. This implies that much effort must be expended in managing the young plants at the time of either out planting or as they germinate. This may be by ensuring adequate moisture and nutrients. It would be important to provide for adequate moisture available to young plants on tailings dam before they can

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withstand the tailings dam conditions.

Acknowledgments The authors would like to thank the following: the Government of the Republic of Zambia and Zambia Consolidated Copper Mines Investment Holdings for their contribution towards the success of the project. Lastly, the authors would like to thank Mssrs Haggai Mulenga, Slade Luwaile and Christopher Kasanyinga for the help rendered during data collection.

References [1]

D.R. Brooks, Reclamation of lands disturbed by mining of heavy minerals, in: R.I. Barnhisel, W.L. Daniel, R.G. Darmondy (Eds.), The Reclamation of Drastically Disturbed Lands, Madison, WI, 2000, pp. 725-754. [2] F.F. Munshower, Reclamation of gold heaps and metal mine wastes, in: R.I. Barnhisel, W.L. Daniel, R.G. Darmondy (Eds.), The Reclamation of Drastically Disturbed Lands, Madison, WI, 2000, pp. 709-723. [3] T.C. Richmond, Revegetation of metalliferous tailings, Madison, WI, 2000, pp. 801-818. [4] D.L. Jacob, M.L. Otte, Influence of typha latifolia and fertilization on metal mobility in two different Pb-Zn mine tailings types, Science of the Total Environment 333 (1-3) (2004) 9-24. [5] L.Y. Jiang, X.E. Yang, Growth response and phytoextraction of copper at different levels in soils by Elsholtzia spledens, Chemosphere 55 (9) (2004) 1179-1187. [6] S.N. Whiting, R.D. Reeves, A.J.M. Baker, Conserving biodiversity: Mining metallophytes and land reclamation, Mining Environmental Management 10 (2002) 11-16. [7] A.J.M. Baker, S.P. McGrath, R.D. Reeves, J.A.C. Smith, Metal hyperaccumulator plants: A review of the ecology and physiology of a biological resource for phytoremediation of metal-polluted soils, in: N. Terry, G.S. Bañuelos (Eds.), Phytoremediation of Contaminated Soil and Water, CRC Press Inc., Boca Raton, FL, USA, 2000, pp. 85-107. [8] ZCCM-IH, Preparation of Phase 2 of a Consolidated Environmental Management Plan, Kitwe, Zambia, 2005. [9] M.J.G. Archer, R.A. Caldwell, Response of six Australian plant species to heavy metal contamination at an abandoned mine site, Water, Air and Soil Pollution 157 (4) (2004) 257-267. [10] T.R. New, Biology of Acacias, Oxford University Press, Melbourne, 1984.


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Importance of Community Participation in Sustainable Utilization of Wetlands: Case of Chebvute in Zvishavane District of Zimbabwe Thomas Marambanyika, Cuthbert Mutsiwegota and Kudakwashe Collins Ralph Muringaniza Department of Geography and Environmental Studies, Midlands State University, Gweru, Zimbabwe Received: March 7, 2012 / Accepted: May 9, 2012 / Published: July 20, 2012. Abstract: Since the turn of the 21st century, the central government in Zimbabwe encouraged community participation in natural resources utilization. The research intends to understand the efficacy of this paradigm shift on sustainable wetland utilization in communal areas, focusing specifically on Chebvute wetland in Zvishavane district of Zimbabwe. Research data was gathered through questionnaires, semi-structured interviews, direct observations and field measurements. These instruments targeted 19 purposively selected plot holders, project chairperson, Environmental Management Agency officer, Agritex officer and the headman. Mapping of the wetland area and its landuse was done using global positioning system receivers and the map was produced using ILWIS, ArcView and Google Earth images. Research findings revealed that the conserved wetland increased its size and biodiversity. Generally, all crops grown had estimated yields higher than the national averages per hectare. The average maize yield was 2.726 tonnes per hectare compared to national average of 0.87. However, conflicts between plot holders, other community members and officials from government institutions such as Environmental Management Agency and Agritex should be ironed out in order to safeguard the wetland’s future. Key words: Community participation, sustainable utilization, wetland utilization.

1. Introduction A wetland is defined in the Environmental Management Act of Zimbabwe Chapter 20:27 as any area of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, and includes riparian land adjacent to the wetland [1]. According to Fuggle et al. [2], a wetland is an area dominated by water due to impeded drainage with both characteristic flora and fauna flourishing. These definitions imply that wetlands are areas that are permanently or temporarily covered with flowing or stagnant water. The physical potential of inland valleys and wetlands in Corresponding author: Thomas Marambanyika, master, lecturer, main research fields: sustainable natural resources utilization, food security, environmental management in industry. E-mail: [email protected]; [email protected].

Sub-Saharan Africa can be conservatively estimated at 135 million hectares and only 1.3% of this potential is actually cultivated [3]. The estimated size of wetlands in Zimbabwe is 1.28 million hectares which is about 4.6% of the country’s land area [3]. There are different types of wetlands. Generally, wetlands in Zimbabwe are of gentle slope with fertile soils formed through gleying process which makes them suitable for crop cultivation [3, 4]. Wetlands in Zimbabwe include floodplains, marshes, pans, swamps and artificial impoundments [5]. Wetlands are important since they provide a wide range of uses including grazing domestic and wild animals, a source of food such as fish, fruits and crops for people, extracting wood for cooking and construction, a source of medicine and water, enshrine religious values as well as providing ecological services such as water purification, climate regulation,

Importance of Community Participation in Sustainable Utilization of Wetlands: Case of Chebvute in Zvishavane District of Zimbabwe

nutrient transfers and flood attenuation [6-8]. Due to rapid increase in human population and high levels of poverty and unemployment, increasing number of marginalized people are moving and settling in fragile wetland areas in search of new means of livelihood through farming in Zimbabwe [6]. Consequently, wetland resources are increasingly degraded through various consumptive uses especially agriculture [9]. This paper seeks to understand the extent to which wetlands can be sustainably utilised through local participation in light of the increased demand for their use to meet people’s growing livelihood needs. Nyakaana [9] noted that defining and achieving sustainable development is a major issue for policy debates both in the developed and developing countries as different approaches and strategies are being harnessed in natural resources conservation and utilization. This has resulted in different schools of thought where policy makers and planners are recommending various of perceived best strategies for managing natural resources including wetlands. According to Mbereko et al. [6], the dominant thinking has been that local use and management of wetlands is damaging to the environment and that local people do not have responsibility over the resources hence external intervention was necessary. This has resulted in prohibitive laws on wetland use in communal areas which were later repealed such as the Water Act of 1976 and Natural Resources Act of 1941 in Zimbabwe. Exclusion of local people in natural resources conservation resulted in ignorance and therefore massive degradation as local communities lack incentives to partake sound conservation strategies. On the other hand, Kangalawe et al. [10] argued that one of the major constraints to wise use of African wetlands is lack of knowledge by planners and natural resource managers on the benefits that they provide and techniques by which they can be utilised in a sustainable manner. This situation results in false premised planning which again champions exclusion of local people, hence intensified resources

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degradation. Dahlberg [7] also indicated that the major threat to availability and access to wetlands is that of competing interests over resources between local communities, conservation authorities and development planners. This was further confirmed by Mbereko et al. [6] as they highlighted that the competing roles of government, traditional institutions, local leadership and non-governmental organizations were responsible for increasing degradation of wetland resources in Zimbabwe. These institutions regulate access, use and conservation of wetlands, hence destructive differences arise due to conflicting roles. Conflicts were also seen by Dahlberg [7] to be a result of lack of engagement amongst various stakeholders with diverse interests and understanding of the wetland environment and its resources. In general, involvement of various institutions has resulted in divergent views and interests on wetland resources to the detriment of this special resource. In light of the above arguments, Shrestha [11] argued that community participation plays a vital role in the development of capacity for the management and utilization of their resources in a sustainable way. This was further echoed by Martin et al. [12, 13] who indicated that effective management of natural resources is best achieved by giving focused value for those who live with them, since an attempt to establish resource management without resource use is likely to be futile or unsustainable. Community participation can be achieved through devolution of authority and capacity building of community based organizations [3]. This was also confirmed by Nemarundwe [15] who noted that destruction of wetlands was due to social and behavioural factors of local community. Evidence to date indicates that local people’s involvement in wetland management can contribute significantly to maintaining or restoring ecological integrity and community well-being [14, 15]. With declining government resources, it is clear that involving local communities as the main actors in wetland

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management is by far the most promising solution to the ever-increasing threats to the integrity of wetlands [14, 15]. However, failure of some community based natural resources management programmes has been noticed in various areas resulting in some scholars questioning the efficacy of the approach. Mukamuri et al. [13] attributed this common failure not to local communities’ participation but to misconstrued participation of local people as they were merely asked to participate in projects conceptualised and developed by external experts and development agencies. Therefore, the question in this regard is, are community projects for communities or for development planners? Silima [16] further attributed failure of natural resources utilization programmes to poor participation of local communities in their planning, implementation and monitoring. Therefore, local communities instead of being custodians of wetland resources through incentives obtained as goods and services, they end up being a degrading force due to lack of shared goals. In Zimbabwe, since the turn of the 21st century there has been a paradigm shift towards putting communities at the core in management and utilization of natural resources. The EMA (Environmental Management Act) through SI (statutory instrument) 230 of 2003 allows for equitable and effective participation of all interested and affected parties in environmental management, including wetlands. Conservation and utilization of wetlands was also embraced and reinforced in the country through its acceptance of the provisions of Ramsar Convention on Wetlands. This convention through its Conference of Parties in 1999 encouraged incentives for local people’s participation for long-term benefits [14]. However, since wetlands are ecologically sensitive areas, through the EMA section 113 subsection 1-3, the minister may impose limitations on development in or around such areas [1]. This act therefore gives leverage for wise use of wetlands by communities. It is in light of this legislative shift and debate on the role of local people

in natural resources management that the research examined the importance of local community participation in sustainable utilization of wetland areas.

2. Methods and Materials 2.1 Study Area Chebvute wetland is located on western part of Zvishavane district in Midlands province, Zimbabwe (Fig. 1). The wetland is found in natural farming region four that receives an unreliable and unpredictable annual average rainfall ranging from 450-650 mm distributed in a unimodal pattern between November and April [17]. Natural farming regions are a classification of the agricultural potential of Zimbabwe, from natural region one (> 1,000 mm of rainfall per annum) which represents high altitude wet areas to natural farming region five which receives low and erratic rainfall averaging 550 mm per annum. Prevailing semi-arid conditions in Chebvute area compromised productivity of rain-fed agriculture for predominantly subsistence farmers in the area. Kangalawe and Liwenga [10] noted that droughts are frequent in Zvishavane district and they normally have severe impacts on household food security. Therefore, Chebvute wetland with its perennial wet conditions provides ideal conditions for all year round farming since irrigation is the only viable option to enhance agricultural production in semi-arid and arid environments. Greyish soils from gleying process are dominant in the area. The wetland is utilized and directly conserved by 86 plot holders from nine villages namely Manyunga, Mudhonga, Chabvepi, Mukwekwe, Hlupo, Musindo, Nyika, Ruzive and Ziyan’a since year 2002. These villages are under chiefs of Hwedza and Mapanzure with the later only in charge of two villages involved, that is, Ruzive and Ziyan’a. 2.2 Methods of Data Collection and Analysis The research generated both quantitative and qualitative data for a detailed understanding of how the

Importance of Community Participation in Sustainable Utilization of Wetlands: Case of Chebvute in Zvishavane District of Zimbabwe 802200

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River Forest Garden Shed Cultivated field in dryland Cultivated field in Wetland Preserved wetland area Chebvute wetland boundary

Location of Chebvute wetland in Zvishavane district of Zimbabwe.

wetland was being utilised and conserved for long-term benefits of both people and the wetland ecosystem. Data was collected using a combination of research instruments such as questionnaires, semi-structured interviews, direct observations aided by checklists and field measurements. A sample size of 22.35% was used representing 19 plot holders who were purposively chosen for questionnaires. Plot size of each sampled farmer was measured and estimated yields of various crops grown were established. Semi-structured interviews were conducted with the project chairperson, headmen, District Environmental Management Agency officer and Agriculture, Technical and Extension Service (Agritex) officer. The Environmental Management Agency officer was selected as she was guiding the local community with technical information on conservation of the

wetland environment and its resources. Agritex officer was responsible for imparting farmers with knowledge and skills on conservation farming for both maximum returns from their agricultural activities and conservation of the wetland which was the primary source of water in the area. Project chairperson who is a member of the community was interviewed to acquire in-depth information on the history of project development, role of plot holders, role of Environmental Management Agency and Agritex, role of non-plot holders who were part of the community but not members of the project, benefits from wetland utilization, conservation strategies implemented and challenges threatening the viability of the project on wetland utilization and conservation. Headman was interviewed on the socio-cultural and economic importance of the wetlands. Direct observations were


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wetland area) were digitized in ILWIS 3.6 and then exported to ArcView 3.2 in order to construct the map of the wetland as well as its surrounding landuse activities.

made to establish an inventory of biodiversity in the wetland area through quadrants. GPS (global positioning system) receiver was used to establish coordinates to map the wetland as well as demarcating landuse in the area. Coordinates from the field were later reprojected from the UTM (universal transverse mercator) projection system to the LatLon (Latitude Longitude) WGS84 in ILWIS (integrated land and water information system) 3.6. These coordinates were overlaid onto a map of the area in Google Earth 5. An image of the area was obtained in JPEG (joint photography experts group) format from Google Earth 5 which was converted to the TIFF (tagged information file format) and georeferenced in ILWIS 3.6 using the UTM projection system (zone 36). Themes depicting the landuse and physical features (cultivated fields, roads, rivers, forest areas and 802500

3. Results and Discussion 3.1 History of Wetland Project Development Chebvute wetland has been in existence since the pre-colonial period when it was managed through indigenous knowledge systems. During the pre-colonial period, the wetland area was regarded as a sacred place. It was spared from human habitation and utilization. People solely benefited from the wetland by fetching water from Chematura River whose source remained the wetland even today (Fig. 2). The indigenous name of the river suggests that it was the source of food for the area. The colonial government

802800

803100

em

at u r a

7764600

7764600

Ch

Legend Road River Forest Garden Shed Grassland

7764300

7764300

N

802500 70

Fig. 2

0

802800 70

140

210

280

350

803100 420 Meters

Landuse in the wetland area and its surroundings.

Cultivated field in dryland Cultivated field in Wetland Preserved wetland area Chebvute wetland boundary


prohibited use of the wetland by the local people. This scenario meant that the government then was responsible for conservation of wetland environment and its resources through LDO (Land Development Officers) who prohibited human activities within 30 metres. According to Environmental Management Agency officer, the post-colonial government continued with colonial policies until year 2002 when the EMA was put in place. The act allowed for the establishment of Chebvute scheme which utilizes the wetland through agriculture for the benefit of both local community and the wetland ecosystem. Before the establishment of Chebvute wetland scheme in year 2002, the size of the conserved wetland was smaller than it is now. The colonial government only managed to fence about 10 hectares of the land, focusing primarily on the core of the wetland without considering the effect of the surrounding area. Today, the size of the wetland is 15 hectares as protection now including forest and grassland on the margin of the wetland (Fig. 2) in order to minimize soil erosion and to provide for protection of a larger biosphere. Currently, 9 hectares of the land is preserved whilst 6 hectares are used for farming in order to improve rural livelihoods in this semi-arid communal area of Zvishavane. According to the project chairperson, the wetland area was almost dry before the current set-up of involving local people in utilization and conservation. Drying of the wetland was due to vandalisation of the existing protection fence between 1980 and 2001, as people wanted to destroy the colonial legacy of denying them access to the important resource. Water was restored in the wetland area in order to establish the current scheme through conservation measures which will be discussed later in this paper. At the inception of the project, people volunteered to be members and they paid a joining fee. Those who are joining now are paying US$5. The people in the project came from surrounding villages such as Manyunga, Mudhonga, Chabvepi, Mukwekwe, Hlupo, Musindo, Nyika, Ruzive and Ziyan’a. Decisions on utilization

837

and conservation of wetland were based on consensus in order to uphold the spirit of fair representation and stewardship. 89% of plot holders were females with males only constituting 11%. Firstly, this exhibits the dominant trend in rural Zimbabwe where households were headed by females with absentee husbands in urban areas or outside the country looking for better income outside agriculture. Secondly, this trend shows a common cultural practice in Zimbabwe where men empower women to run small projects whilst they focus mainly on seasonal cropping on larger portions in dryland and cattle production. Therefore, access to the wetland was not dependent on gender lines despite the fact that the community was highly patriarchal. Although the wetland is primarily used and conserved by local people, there are other stakeholders involved in capacity building. These include Agritex officers, Environmental Management Agency officers, local and traditional leaders (councillors, kraalheads, headmen and chiefs). 3.2 Capacity Building for Sustainable Wetland Utilization Environmental Management Agency officer indicated that before the commencement of the project, all project members were educated on effective use and conservation of the wetland. Moreover, beneficiaries took part in look and learn tours of similarly established wetland projects in Zimuto area in Masvingo province and Murehwa area in Mashonaland East province. Experiences from these tours were used as part of training programme to share ideas and views on good farming and conservation methods being practiced in visited areas. Contrary to findings by Ref. [5] that there was lack of training specifically targeted to wetland utilization and development in the SADC (Southern Africa Development Community) region, at Chebvute wetland training programmes and awareness campaigns were conducted by Agritex officers, Environmental Management Agency officers, donors and pioneer members of the scheme (Fig. 3).

838

Fig. 3


Training providers on sustainable utilization of wetland.

All plot holders concurred that it was the training received from the aforementioned government institutions which significantly enhanced their ability to sustainably utilise the wetland. Initially, plot holders in Chebvute got support from SADAMP (Small Holder Dry Areas Management Programme) in the form of seeds, fertilizers and fence to protect the area from domestic animals which could destroy the wetland through trampling as well as crops in the fields. New members joining the scheme also received training from experienced pioneer plot holders. 3.3 Motivations to Wetland Use and Conservation There was growing concern in the decline of the fragile and sensitive Chebvute wetland among the local people and government arm responsible for environment conservation, the Environmental Management Agency. A number of factors influenced the local people to conserve the wetland as shown in Fig. 4. The majority of the plot holders (95%) interviewed revealed that the major reason they voluntarily joined the project was to conserve the wetland from further degradation threatening its extinction. This was in light

of increased unsustainable use of the wetland as people resorted to poaching of resources such as timber in the area in order to evade prosecution from government officials, then under Natural Resources Board, who were in charge of protecting the place. Degradation of the wetland was mainly attributed by all plot holders to exclusion of the local people in ownership, access and use of the wetland. Another factor which contributed to the establishment of the current wetland project was poverty as the existing climatic conditions perpetuated food insecurity. The area received mean annual rainfall of 500 mm. All plot holders indicated that increased rainfall scarcity made the wetland the only reliable source of water for annual farming due to lack of irrigation infrastructure in the area. Since all farmers in the wetland area lack enough capital to embark on capital intensive farming, fertile soils in the area also provided a low cost opportunity for enhanced production amongst farmers. Plot holders (67%) were also motivated by experiences of sustainable livelihoods observed during tours in Zimuto and Murehwa wetlands. It is through these tours that farmers realised the potential of wetlands to enhance rural livelihoods. The project


Local Donors

traditions

and

customs

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Poaching (e.g., timber, reeds, fish etc.)

Experiences from Environmental

established wetland

education (e.g., by

projects e.g. Zimuto and

EMA and Agritex)

Murehwa

Drivers to sustainable wetland utilization Lack of capital

Change in

(e.g. for irrigation)

government environmental legislation

Fertile soils

Low rainfall

Poverty and food insecurity

Fig. 4 Drivers to sustainable wetland utilization.

chairperson indicated that support from SADAMP, especially fence boosted confidence amongst farmers as it meant minimized crop destruction by domestic animals especially during the winter season when they roam freely. In addition, the local communities were motivated by the realization that Environmental Management Agency now considered their rights to access and use of the wetland in a sustainable manner. This was shown by change of Environmental Management Agency’s motto as confirmed by its officer to: “Protecting the Environment, with People in Mind”. This policy shift made Chebvute community realize that it was their mandate to conserve the wetland, that is, it gave them sense of responsibility. Maintenance of the wetland further made Chematura River perennial since the wetland provided a permanent source of water, hence gardens were established downstream and livestock had annual source of drinking water. This scenario meant that

people in the area were to maintain large and healthier herds of cattle which were also their major source of income through selling and provision of draught power. Furthermore, existence of the wetland meant that water tables in the area remained high allowing wells and boreholes not to dry up. With these benefits in mind, all plot holders felt motivated to conserve the wetland. 3.4 Biodiversity in the Wetland The wetland area was found to be endowed with different animal and plant species. Common type of animals found in the area were warthogs, baboons, monkeys, duikers and at one point elephants. These animals were attracted to the area by evergreen natural vegetation which provided both habitat and grazing pasture as well as a source of drinking water. Vegetation in the protected wetland area can be classified as forest, mountain, aquatic and grassland (Table 1 and Fig. 2).

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Table 1 Tree species distribution in and around Chebvute wetland. Forest Acacia rehmanniana (muunga) Dichrostachys cinerea (mupangara) Acacia karroo (mubayamhondoro) Bauhinia thonningii (musekesa) Uapaca kirkiana (muzhanje) Strychnos spinosa (mutamba) Parinari curatellifolia (muhacha) Pterocarpus angolenses (mubvamaropa) Syzigium guineense (mukute) Ficus natalensis (muonde) Ficus capensis (mutsamvi) Brachystegia spiciformis (musasa) Julbernadia globiflora (mutondo) Euphorbia ingens (mukonde) Acacia polycantha (chitataunga)

Mountain

Grassland

Acacia rehmanniana (muunga) Siebenana (rukato) Acacia sieberana (muunga) Brachystegia boehmii (mupfuti) Brachystegia glaucescens (muunze) Brachystegia spiciformis (musasa) Julbernadia globiflora (mutondo) Euphorbia ingens (mukonde)

Acacia karroo (mubayamhondoro) Dichrostachys cinerea (mupangara) Bauhinia thonningii (musekesa) Ficus natalensis (muonde) Ficus capensis (mutsamvi)

Tree species found in the wetland represent almost all tree species scarcely found in the surrounding communal area under different ecological conditions. Forest ecosystem is dominated by more tree species due to its adjacent location to water (Fig. 2). Aquatic ecosystem was dominated by reeds and buffalo grass. The existence of the various tree, grass and animal species shows that local community was succeeding in conserving biodiversity on the wetland and its surrounding area. 3.5 Benefits of Wetland Farming The major economic activity carried out in the wetland was farming. According to the project

160 m2

Fig. 5 Plot sizes of sampled farmers in m2.

170 m2

chairperson, the average plot size for each farmer was 200 m2. However, the average plot size from the sampled farmers was 188 m2 with variations as shown in Fig. 5. The size of each farmer’s plot was determined by the time of joining the scheme, the means of land acquisition and availability of land. 58% of farmers who indicated that they volunteered to join the scheme at its inception had plot sizes above 200 m2 whilst 37% and 5% of farmers who later acquired land through traditional leaders and parents respectively had plots of less than 200 m2 (Fig. 5). Majority of farmers (84%) on Chebvute wetland grow various crops for both subsistence and commercial purpose. Due to perennial availability of

180 m2

200 m2

240 m2


water, all sampled farmers indicated that they have got three cropping seasons per year. Crops grown include maize, sugar beans, potatoes, tomatoes, wheat, onions, cassava, bananas, leafy vegetables, peas, carrots, pumpkins and sweet potatoes. All farmers specialize in at least two of the indicated crops with maize and beans being the most popular. Maize is grown by 83% of the farmers since it is a staple food. The Agritex officer indicated that farmers in the wetland harvest were earlier than those in irrigated areas in the district. Hence, their produce fetched fairly high prices due to less competition on the market. Generally, farmers obtain high yields from crops grown in the wetland (Table 2). Majority of farmers (68%) indicated that agricultural benefits from the wetland were far much better than those obtained from dryland. According to Agritex officer, Zvishavane area is not recommended for maize, potatoes and beans cropping as even in a good farming season harvests are far less than 1 tonne per hectare. However, the average maize yield obtained of 2.726 tonnes per hectare was higher than Midlands province’s average of 0.68 tonnes per hectare in season 2009/2010, the national average of 0.74 tonnes per hectare in 2009/2010 and national 10 year (2000-2010) average of 0.87 tonnes per hectare as shown in Ref. [18]. Sugar beans output of 1.237 tonnes per hectare was above national average of 0.56 tonnes per hectare in season 2009/2010. Therefore, the wetland availed an opportunity for local people to grow crops not permitted by general agro-ecological conditions in the area. Considering that farmers involved in wetland

841

utilization harvest thrice per year, 77% of them were food secure. However, farmers’ yield per crop varies irrespective of existence of fertile gleysols across the farming area. The major problem was that farmers along the fence often lost yield to domestic and wild animals raiding as the fence is sometimes vandalised. Agritex officer indicated that farmers plant at different times hence some were exposed to pests and diseases depending on timing. Agritex officer further revealed that lack of income to buy inputs also compromised some farmers’ productivity level. 17% of plots were owned by old farmers who rely on child labour. According to Agritex officer and project chairperson poor management in these plots often resulted in low output. Generally, the wetland remained the major source of food and income for school fees among plot holders. Whilst farming was the major landuse in the wetland, all plot holders and the project chairperson indicated that the wetland also provided other benefits such as fishing, thatch grass, fencing poles, beekeeping as well as medicine from existing biodiversity. Non-plot holders in the surrounding villages also benefited directly and indirectly from wetland conservation. Direct benefits include water for gardening downstream and cheap farm produce from farmers in the wetland whilst indirectly EMA officer indicated that it controls wildfires and floods. 3.6 Measures Applied to Conserve the Wetland Benefits from wetland utilization significantly changed attitude of plot holders towards wetland

Table 2 Average annual yield from each sampled farmer. Number of sampled farmers Average estimated yield for each Average estimated yield for who responded sampled farmer (kg/188 m2) each sampled farmer (ton/ha) Tomatoes 3 190 3.572 Beans 12 65.8 1.237 *Maize 12 145 2.726 Potatoes 2 132 2.482 Wheat 2 62.2 1.169 * Figures are shown for dried maize only as farmers failed to estimate quantities for green maize sold. This means that output of maize is higher than what is shown in the table. Crop

842


conservation as confirmed by all plot holders who responded to questionnaires. Plot holders participated in wetland conservation in various forms as shown in Fig. 6. The project chairperson revealed that the current wetland management system’s sustainability was largely hinged on division of labour. All plot holders including traditional leadership indicated that the wetland area was also partly preserved through traditional beliefs. It was believed that the wetland is home to mermaids which superstitiously cause disappearance of violators of traditional customs in the area. For example, dirty pots were not allowed to fetch water, people must not wear black clothes and vulgar languages were prohibited near the wetland. Sometimes disappeared cattle and people are heard rumbling in the wetland. However, on daily basis the major conservation activity done by plot holders was wetland guarding as indicated by 32% of farmers. Plot holders indicated that they guard the wetland to curb fence vandalisation, illegal grazing by domestic animals and illegal destruction of crops and trees. Moreover, 32% of the interviewed farmers revealed that they practiced conservation agriculture which involves crop rotation, minimum tillage and maintenance of 30% ground cover as advised by Agritex officers. Agritex officers were ensuring strict adherence to conservation farming on each plot. This allows the plot holders to maintain soil fertility, retain

Fig. 6 Conservation methods used in the wetland.

moisture and minimize soil erosion by growing cover crops like beans and pumpkins. Fence was maintained regularly and sand traps were established upslope to minimize soil erosion into the wetland. These conservation methods managed to preserve the wetland to its current size of 9 hectares. Lastly, the Environmental Management Agency officer indicated that illegal cutting of trees in the forest on wetland hinterland was prohibited unless permission was granted through traditional leadership. 3.7 Challenges to Sustainable Wetland Utilization and Conservation Despite improved benefits from the wetland amongst local people, a number of identified factors were still threatening sustainable utilization of the wetland. The major problem as revealed by 36% of plot holders was that of fence vandalisation resulting in domestic animals accessing the wetland. According to Environmental Management Agency officer, cattle trampling was associated with drying of some peripheral parts of the wetland area. Contrary to Svotwa et al. [4, 6] findings that cattle were allowed for grazing in wetlands in communal areas of Zimbabwe, in Chebvute wetland they were not allowed since cattle trampling was identified as a degrading factor. 26% of farmers indicated that they were being demotivated by wild animals such as warthogs which constantly invade


their fields especially during the evening, hence unprecedented crop loss. 54% of farmers revealed that absence of mesh wire allowed the problem of crop destruction by wild animals and goats to continue. Furthermore, 26% of farmers also indicated that conflicts between plot holders and non-plot holders threaten sustainable utilization and conservation of the wetland as non-plot holders were accused of stealing from the fields, illegal cutting down of trees in the forest area and destroying the fence to allow their animals to have access to grazing. Agritex and Environmental Management Agency officers observed that some farmers disregard technical advice given such as need for conservation farming and opt for intensive application of inorganic fertilizers which was likely to cause water pollution. Moreover, Agritex and Environmental Management Agency officers indicated that some plot holders on several occasions tried illegal extension of their farming area into the preserved wetland area. These actions were signs of lack of cooperation in protecting the wetland by some few (4%) farmers. However, the interviewed culprit farmers were fully aware of the negative consequences of their activities. These plot holders were only concerned with utilizing the wetland for profit making rather than conserving it. Lastly, 7% of farmers indicated that the involvement of Environmental Management Agency was interfering and weakening their role as the custodians of the wetland to sustainably conserve this resource. They indicated that Environmental Management Agency was influencing most decisions on wetland conservation hence undermining their independence on decision making and amount of benefits obtained. This shows that competing roles of local people and other stakeholders undermine performance of community based natural resources management programmes.

4. Conclusion Local people’s participation has resulted in restoration and increase in size of the wetland

843

ecosystem. This is evidenced by abundance in flora and fauna species. Sustainable wetland utilization was achieved through empowering local communities as primary users and preservers whilst technical support came from government agencies such as Agritex and Environmental Management Agency. Methods used to conserve the wetland include establishment of sand traps, fencing, sustainable agriculture, traditional taboos and guarding. Crop productivity was higher in the wetland than dryland per unit area. This acts as a major motivator since farmers managed to improve their food security and income in this semi-arid area where chronic food insecurity is experienced. However, wetland existence is likely to be compromised by conflict between plot holders and non-plot holders, conflict between plot holders and Environmental Management Agency, disregarding of technical advice by farmers from Agritex, lack of finance to maintain fence in order to eradicate increased encroachment by domestic animals and poaching of wood. Generally, community participation largely proved to be a panacea to sustainable wetland utilization although there is no project without some loopholes.

5. Recommendations  The excluded community members (non-plot holders) should be involved in utilizing and conserving the wetland so that everyone would have a sense of ownership hence minimizing degradation;  Some of the profit realized from the selling of crops should be reinvested for the maintenance of the wetland, for example, buying fence and agroforestry activities instead of relying on donors;  Women should assume higher positions in the committee since they represent the majority to minimize their level of disgruntlement;  Mesh wire must be installed around the gardens to eliminate crop destruction by domestic and wild animals;  Controlled hunting of wild animals must be introduced to minimize damage of crops by animals.

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References [1]

Environmental Management Act Chapter 20:27, Government of Zimbabwe, Government Printers, Harare, 2003. [2] R.F. Fuggle, M.A. Rabie, Environmental Management in South Africa, Juta and Co. Ltd, Johannesburg, 1992. [3] K. Fenken, I. Mharapara, Wetland development and management in SADC countries, in: Proceedings of a Sub-regional Workshop, Harare, Zimbabwe, Nov. 19-23, 2001. [4] E. Svotwa, I.O. Manyanhaire, P. Makombe, Sustainable gardening on wetlands in the communal lands of Zimbabwe, Electronic Journal of Environmental, Agricultural and Food Chemistry 7 (3) (2008) 2754-2760. [5] Zimbabwe’s Fourth National Report to the Convention on Biological Diversity, Ministry of Environment and Natural Resources Management, Government of Zimbabwe, Harare, 2010. [6] A. Mbereko, M.J. Chimbari, B.B. Mukamuri, An analysis of institutions associated with wetlands use, access and management in communal areas of Zimbabwe: A case study of Zungwivlei, Zvishavane, Physics and Chemistry of the Earth 32 (2007) 1291-1299. [7] A. Dahlberg, Local resource use, nature conservation and tourism in Mkuze wetlands, South Africa: A complex weave of dependence and conflict, Geografisk Tidsskrift, Danish Journal of Geography 105 (1) (2005) 43-55. [8] S. Bethune, O.C. Ruppel, Review of Policy and Legislative Support to the Sustainable Use of Wetlands in the Zambezi Basin, Final report (Namibia), IUCN ROSA, 2007. [9] J.B. Nyakaana, Sustainable wetland resource utilization of Sango Bay through eco-tourism development, African Journal of Environmental Science and Technology 2 (10) (2008) 326-335. [10] R.Y.M. Kangalawe, E.T. Liwenga, Livelihoods in the

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[18]

wetlands of Kilombero Valley in Tanzania: Opportunities and challenges to integrated water resource management, Physics and Chemistry of the Earth 30 (2005) 968-975. U. Shrestha, Community participation in wetland conservation in Nepal, Journal of Agriculture and Environment 12 (2011) 140-146. R.B. Martin, Murphree’s laws, principles, rules and definitions, in: Beyond Proprietorship: Murphree’s Laws on Community-Based Natural Resource Management in Southern Africa, International Development Resource Centre, Ottawa, 2009. B. Mukamuri, J. Manjengwa, S. Anstey, Introduction, in: Beyond Proprietorship: Murphree’s Laws on Community-Based Natural Resource Management in Southern Africa, International Development Resource Centre, Ottawa, 2009. M. Gawler, What are best practices? Lessons in participatory management of inland and coastal wetlands, in: The 2nd International Conference on Wetlands and Development, Wetlands International, Wageningen, Netherlands, 2000. N. Nemarundwe, Negotiating resource access: Institutional arrangements for woodlands and water use in southern Zimbabwe, Ph.D. Thesis, Swedish University of Agricultural Sciences, Uppsala, 2003. V. Silima, A review of stakeholder interests and participation in the sustainable use of communal wetlands: The case of the Lake Fundudzi catchment in Limpopo Province, South Africa, MED Thesis, Rhodes University, 2007. L.M. Zinyama, D.J. Campbell, T. Matiza, Coping with food deficits in rural Zimbabwe: The sequential adoptions of indigenous strategies, Research in Rural Sociology and Development 5 (1991) 23-34. FAO/WFP Crop and Food Security Assessment Mission to Zimbabwe, Economic and Social Department, FAO, Harare, 2010.


D

DAVID

PUBLISHING

Management of Solid Waste in a Market: Case Study of Bodija Market, Ibadan, Nigeria Omolara Lade, Oluwole Agbede and Oluseun Ilori Department of Civil Engineering, University of Ibadan, Ibadan, Nigeria Received: June 18, 2012 / Accepted: July 17, 2012 / Published: July 20, 2012. Abstract: Solid waste management in developing countries has assumed the scale of a major social and environmental challenge. However, many developing countries such as Nigeria have a chronic solid waste management problem. Poorly managed solid waste in market has resulted in health hazards and environmental disaster due to contamination by vermin. This paper studies the management of solid waste in Bodija market, Ibadan, Nigeria. The study adopted a quantitative approach, employing waste composition analysis of samples from the case study area, and questionnaire survey as key methods for data generation. Analysis of result reveals poor collection practise in the market with 6.7% respondents practicing open burning of refuse. However, high rate of waste generation in the market, inconsistency and inefficiency of the private collection agents and lack of funds on the part of the waste management authority has led to this practise. In the next two decades, a total volume of 282,000 m3 of landfill site would be needed for solid waste disposal in the market. The sanitary landfill technique has the potential to reduce environmental health problems created by the existing disposal methods. Hence, cost recovery practises and reconstruction of management capacity are recommended as solutions to the problem. Key words: Solid waste management, market, landfill, Ibadan, sustainability.

1. Introduction In Nigeria, solid waste has become an important issue with piles of wastes often found in roads, rivers and many other open spaces in the cities resulting in significant health and environmental problems. The state of solid waste management in cities of most developing countries is a major social and environmental challenge [1, 2]. In SSA (sub-Saharan Africa), the situation has been worsened by the combined influence of poverty, population growth and rapid urbanization [3, 4]. A high level of attention has been given to it in the UN (United Nations) millennium declaration of September, 2000 as three of the eight millennium development goals outlined in the declaration have waste or resource efficiency implications [5]. In response to the waste challenge, many developed Corresponding author: Omolara Lade, Ph.D. student, engineer, main research field: water resources and environmental engineering. E-mail: [email protected].

countries have embarked upon ambitious environmental reforms, recording remarkable advances in best practises and sustainable management of their MSW (municipal solid waste). Nigeria typifies many SSA countries with chronic waste management problems. It has a large population of over 140 million people according to census statistics [6]. Population growth rate, rapid urbanization and an unevenly distributed wealth occasioned by huge oil income are factors influencing waste growth in the country [7]. The urban population is growing at an alarming rate. The population growth rate is above global average of 2.9% per annum while the rate of urban growth is as high as 5.5% per annum [8]. This paper is a case study of MSW management in Bodija market, Ibadan, Nigeria. Solid waste management has constituted a serious environmental problem in urban and developing country like Nigeria as improper management of waste has led to degradation of the environment. The

846

Management of Solid Waste in a Market: Case Study of Bodija Market, Ibadan, Nigeria

major streets in Ibadan are partially and wholly blocked by solid waste. It was revealed that household waste collection and street cleaning are restricted to wealthy neighborhoods, while in the remaining areas, household wastes are dumped along roads, which are in illegal dumps and in storm water drains or is buried [9]. It was also revealed that 35% of Ibadan households lack access to waste collection. Insufficient and improper collection of waste leads to environmental health risks. It was revealed that waste dumped into storm drainage channels, lagoons, creeks and other water impoundment points create serious environmental problems, which can escalate into disastrous situations [10]. The 1982 floods in Ibadan, Lagos, Port Harcourt and Aba that led to loss of lives and property was partly a result of blockage of drainage channel by refuse in these cities. Waste generation by all living things is inevitable. The rapid population growth coupled with increasing business activity, and high rate of consumption have led to an increase in the quantities of solid waste generated. In developing countries 20%-50% of the recurrent budget is spent on solid waste management, yet 30%-60% of all urban waste is not collected and less than 50% of the population is served. Ibadan city lies between latitudes 7°19′ and 7°29′ north of the equator and longitudes 3°47′ and 3°58′ east of the Greenwich Meridian (Fig. 1). Ibadan is the capital of Oyo state and is reputed to be the largest city in West Africa, south of Sahara, with a population of 2,580,894 [6]. Bodija market was established in 1987, and is about five minutes drive from the University of Ibadan campus. The market is well planned with the largest collection and distribution centre of foodstuff, timber, meat, goats and cattle in the southwest of Nigeria.

2. Materials and Methods 2.1 Materials The properties of waste, nature and rate at which the waste is disposed were determined. A survey on waste

generation pattern was conducted on each shop in the market. Sampling areas were carefully chosen to ensure that the data obtained is consistent with the objectives of the project. Sampling techniques and equipment were chosen to receive information on the parameter such as sampling point, characteristics of the samples, number of sampling site etc.. 2.2 Sampling Method A direct random sampling method was conducted to determine the volume required for storage of domestic waste or to investigate the recycling potential of waste. The study area was divided into three categories based on the materials used in constructing these shops: Category A (open stalls), Category B (covered stalls) and Category C (shops). The waste sample was emptied into carton of known cross-sectional area, height and mass. The height of the waste from the top of the carton was measured and recorded and this is used in computing the height as well as the volume of the waste. The waste in the carton was then weighed and recorded. This result is also used in computing the mass as well as the density of the waste. Three samples (each of waste generated in a day) were collected from each of the three categories and the average is computed for each of the category. The average from the three categories was then averaged to determine the mass generated per day from the market. 2.2.1 Density Measurement A carton was given out to each randomly selected shop, to use as storage for their daily waste generation. An education program was carried out for the occupants of the shop to give them an awareness of the program and its uses. There was a general inspection and supervision of the selected shops at regular intervals, to ensure that they comply with the instructions given. The carton containing the refuse was weighed, and the weight of the empty carton was also known. A ruler was used for measuring the height of the refuse in the


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Fig. 1 Map of Nigeria showing the study area.

carton, the length and width of the container was known, and this gives the cross-sectional area. Then, the weight of the empty carton was taken. The waste was analyzed on a daily basis and the density was calculated. 2.2.2 Composition Measurement This involves the determination of the percentages by mass of the various constituents of the waste in order to determine the percentage of the proportion of salvageable material, proportion of biodegradable material etc. to be able to design an efficient and proper collection, storage, treatment and disposal method. In achieving this, the waste sample was emptied on a clean slate after weighting the total mass. The waste was then sorted out into its various constituent and the weight of each constituent was taken, but precautions were taken to avoid loss in total weight while this process was carried out. This was followed by expressing the weight of each constituent as a percentage of the total sample for each shop under study.

3. Results and Discussion The results of the test carried out to determine the generation rate, density and waste composition of the

solid waste are shown in Figs. 2-4. While the results of the average waste generation rate, average density and volume are shown in Tables 1 and 2, respectively. 3.1 Waste Generation in the Market It was revealed from this research that 4.24 million kilograms of solid waste is generated in Bodija market in a year given 2008-estimated population of the market to be 16,000 people. The waste generated per annum will continue to increase with increasing population growth. The type of goods sold in the market determines the type of waste generated in the market. These include nylon, paper, cloth, garbage, wood, glass, metal, vegetable/leaf, dust/ashes and stone. Fig. 5 reveals that dust is ranked highest (30.59%) that is they are the most commonly generated waste in the market because the market is unpaved. Next to this is nylon (21.77%). 3.2 Sanitary Landfill as a Disposal Technique Sanitary landfill is an engineering method of disposing solid wastes on land by spreading them in thin layers, compacting them to the smallest practical volume and covering them with soil each working day in a manner that the environment will be protected.

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Average Waste Nylon Composition Paper

Average Waste Composition Nylon

Cloth Garbage Wood Glass

0

Paper

0.64

Cloth

19.34

Garbage 12.83 0.72

Glass

8.88

11.4

Metal

0.57

Plastic

1.21 2.31

20.79 33.53

6.24 3.94

22.33

Wood

3.82

1.05

4.54

Stone

3.75

7.91 23.7

3.13

6.81

Metal Plastic Stone Dust Leaf Rubber

Dust Leaf

0.57

Rubber

Fig. 2 Average waste composition of category A. Source: Ref. [11].

Fig. 4 Average waste composition of category C. Source: Ref. [11].

Landfill is:  the only method that does not involve other methods for proper disposal;  environmental pollution control measure since burning is eliminated;  suitable for adequate and proper control of rodents and insects;  suitable for biodegradation of greater percentages of the waste. 3.3 Landfill Design

Fig. 3 Average waste composition of category B. Source: Ref. [11].

Population P = 16,000 people; Let population projection for n = 20 years = P20; Growth rate = 2.38% [6]; Pn = P (1 + r)n; P20 = P (1 + r)20; P20 = 16,000(1 + 0.0238)20; P20 = 25,611 people; Average rate of waste generated = 0.453 kg/capita/day; Total weight generated = 0.453 × 25,611 × 365 = 4.24 × 106 kg/year; Volume required = 4.24 × 106 kg/year; = 8,469.3 m3/year;


849

Table 1 Average waste generation rate. Category of shops

Description of shops

Average occupants

A B C

Open stall Stalls Shops

6 4 6

Average waste generated/ shop/day 2.47 1.78 2.79

Average weight generated/ head/day 0.41 0.48 0.46

Table 2 Average density and volume. Category of shops A B C

Average waste generated/shop/day 2.47 1.78 2.79

Average Total Waste Composition Nylon

Paper Cloth Garbage

5.03

Wood

0.28

Glass 30.59

21.77

Metal 10.69

Plastic Stone

2.46 6.37

0.85 2.52

12.56

Dust Leaf Rubber

2.95 3.92

Fig. 5 Average total waste composition. Source: Ref. [11].

Design volume = 8,469.3 × 1.33 = 11,264.2 m3/year; Allowance for 20% of volume required for cover; Volume of landfill = 11,264.2/0.8 = 14,080.25 m3/year; Volume of landfill required in one year = 14,100 m3; Volume of landfill required in 20 years = 14,100 × 20 = 282,000 m3.

4. Conclusions The management of solid waste is a serious environmental problem in many markets in Ibadan especially Bodija market. Solid waste is produced in large amounts due to rapid population growth. Hence,

Volume of waste (m3) 0.01 0.02 0.01

Density of waste (kg/m3) 280.10 79.60 272.00

it is mostly disposed of by open dump and burning resulting in environmental pollution. The Ibadan solid waste management is not efficient enough to ensure that waste is properly disposed. A total volume of 282,000 m3of landfill site would be needed for solid waste disposal in Bodija market for the next 20 years. The sanitary landfill disposal technique has the potential to reduce environmental health problems created by the existing method of disposal. Other suggested solutions to the problem are cost recovery and restructuring of management capacity.

References [1]

[2]

[3]

[4]

[5]

[6]

J.C. Agunwamba, Analysis of scavengers’ activities and recycling in some cities of Nigeria, Environmental Management 22 (2003) 849-856. C. Ezeah, Analysis of barriers and success factors affecting sustainable municipal solid waste management in Abuja, Nigeria, Ph.D. Thesis, University of Wolverhampton, UK, 2010. Study on Solid Waste Management Options for Africa, Sustainable Development and Poverty Reduction Unit, African Development Bank (AfBD), Johannesburg World Summit on Sustainable Development (WSSD), 2002. A.H. Igoni, M.J. Ayotamuno, S.O.T. Ogaji, S.D. Probert, Municipal solid-waste in Port Harcourt, Nigeria, Applied Energy 84 (2007) 664-670. Africa and the Millennium Development Goals, United Nations Organization Web site, 2007, http://www.un.org/millenniumgoals/ (accessed June 14, 2007). National Population Commission: Population Census Figures Abuja, Nigeria [Online], 2007, http://www.population.gov.ng (accessed Aug. 28, 2008).

850 [7]

[8] [9]

Management of Solid Waste in a Market: Case Study of Bodija Market, Ibadan, Nigeria The Economist, Country Profile: The Economist Intelligence Unit, Nigeria [Online], 2007, http://www.economist.com/countries/nigeria (accessed June 15, 2007). Solid Waste Sector Appraisal Report, Urban Development Bank of Nigeria (UDBN), 1998. A. Fantola, Introduction to Solid Waste Management

Engineering, Bibs Press, Ibadan, 1997, pp. 3-6. [10] O.A. Agbede, Environmental Impact Assessment: Engineering Geology Aspect, Oyo State, Nigeria Urban, Development Project Lead Consultants, Nigeria, 1996. [11] O. Ilori, Solid waste management in Bodija Market, Nigeria, B.Sc. Thesis, University of Ibadan, Nigeria, 2008.


D

DAVID

PUBLISHING

Vulnerability to Desertification in Lebanon Based on Geo-information and Socioeconomic Conditions Talal Darwish1, Pandi Zdruli2, Ramy Saliba2, Mohamad Awad1, Amin Shaban1 and Ghaleb Faour1 1. National Center for Remote Sensing, National Council for Scientific Research (CNRS), Beirut 11072260, Lebanon 2. Land and Water Resources Management Department, Mediterranean Agronomic Institute of Bari, Valenzano 70010, Italy Received: July 5, 2012 / Accepted: July 10, 2012 / Published: July 20, 2012. Abstract: Desertification caused by land degradation and overexploitation of natural resources is threatening large parts of eastern and southern Mediterranean. The actual state of desertification sensitivity in Lebanon was spatially assessed using site specific environmental bio-physical indicators, demographic pressure and socioeconomic conditions. Bio-physical assessment included the aridity index derived from integrated assessment of the historical data for 48 climatic stations spread throughout the country, the new detailed soil map at 1:50,000 scale, and the updated land cover/use map at 1:20,000 derived from IKONOS 2005. The methodology also included livelihood conditions and poverty at local administrative “Caza” level. Results showed the integrated impact of local climate, soil and vegetation quality and socioeconomic conditions on sensitivity to desertification. A total of 78% of the territories have low and very low climate quality index preconditioning the sensitivity to desertification. Fourteen Cazas out of 26 in total, representing more than 66% of the country, have low socioeconomic satisfaction index. Furthermore, negative trends are alleviated by good quality relict soils and vegetation cover. The actual extent of desertification covers 40.48% of the national territory, much of which occurs under semi-arid climate, moderate or low soil and vegetation quality and poor living conditions. The outcome of this research adjusted the previous coarse estimates of desertification prone areas at the national level. Results allow for realistic, policy oriented local assessment for responsive land use planning and proactive sustainable, national and local land management in the context of the national action plan to combat desertification. Key words: Integrated assessment, land degradation, east Mediterranean, sensitivity, sustainable land management.

1. Introduction Climate conditions, demographic pressure, poverty and mismanagement of land resources in the drylands multiply the severity of soil degradation and extent of areas prone to desertification resulting in land abandonment [1]. Lebanon is also threatened by desertification and overexploitation of natural resources. The sensitivity to degradation arises from the abrupt changes in topography with a striking diversity of climate and soils [2], vegetation cover [3] and accelerated soil erosion [4, 5]. Pressure is exacerbated by intensive agriculture causing soil salinity [6], land use change and reduction of green 

Corresponding author: Talal Darwish, Ph.D., main research fields: soil science, land degradation. E-mail: [email protected].

cover [7], rapid population and urban growth [8], overgrazing of marginal lands [9] and chaotic quarries expansion [10] beside the mismanagement of water resources leading to seawater intrusion and contamination of aquifers [11, 12]. A first assessment of desertification prone areas was completed in 2003 at 1:200,000 scale [13]. Given the small size of Lebanon, a more detailed scale was needed to account for local variability. Factors affecting land sensitivity to degradation were classified into bio-physical and socioeconomic drivers emphasizing the ecological, demographic and economic aspects of the problem [14]. The integration of the bio-physical and socioeconomic dimensions of land degradation has taken a step further by Lorent et al. [15] who evaluated the impacts of subsidies on the

852

Vulnerability to Desertification in Lebanon Based on Geo-information and Socioeconomic Conditions

profitability of traditional agricultural activities, and combined these findings with spatially explicit bio-physical information derived from remote sensing. In this study, a set of indicators to assess the bio-physical status of the Lebanese land was used, including climate, soil and vegetation beside the demographic pressure and management as described in previous studies [1, 16-18]. This new attempt to map desertification sensitive areas was possible with the release of new soil data at 1:50,000 scale [19] and new land cover/use map of Lebanon at 1:20,000 scale [20]. To complement this study, the socioeconomic conditions involving indicators like the fulfillment of population’s basic needs and the level of income were incorporated. Poverty and wealth are highly associated with population dynamics as inhabitants aggravate or attenuate the pressure on land resources through their wise or unsustainable activities and interaction. For this purpose, the updated analysis of living conditions [21] to better illustrate the abiotic pressures exerted on land with significant impact on the degradation process exposing the territory to desertification were used. 1.1 Area of Study Lebanon is located on the eastern shore of the Mediterranean Sea between 33° and 35 °N latitudes, and 35° and 37° E longitudes (Fig. 1). Lebanon mountainous

(10,452

km2)

country

is

with

a

predominantly

complex

physical

geography. Landform, climate, soils, and vegetation differ markedly within short distances. The country is characterized

by

four

main

geomorphological

(physiographical) units: a narrow coastal plain and two mountainous chains (Mount Lebanon and Anti

Fig. 1 Geographical location of Lebanon.

clearly distinguished seasons: hot and dry summer, cool and rainy winter, moderately dry fall and spring. While the coastal and mountainous areas are characterized by abundant rainfall (up to 1,200 mm) mainly distributed between December and March, the Bekaa Valley has a semi-arid to continental climate with unpredictable rainfall and recurrent drought. In the central part, the climate is semi-arid; whereas in the north-east it is almost arid to continental, since it is separated from the sea effect by the presence of a high and ridge mountain chain exceeding 3,000 m of altitude. In the southern Bekaa Valley, a sub-humid Mediterranean climate is dominant, with more reliable rainfall. The number of rainy days is between 60 and 80 days in Mount Lebanon and coastal plain and decreases to 50 days in the Bekaa valley and accounts for 50-60 days in the Anti-Lebanon mountain chain [22]. At very high altitude, patches of snow cover might remain 6-9 months.

Lebanon) separated by a fertile and relatively elevated

1.2 Soil Cover

depression (700 to 1,100 m altitude) named the Bekaa

Out of 32 soil groups known worldwide by the World Reference Base for Soil Resources [23] a total of 13 groups and 106 soil units were identified in Lebanon [19]. The most widespread soil type in Lebanon is the shallow Leptosol which is receiving the highest anthropic pressure due to the historical

valley. Lying northeast to southwest, the two mountain chains occupy around 70% of the Lebanese territory. A major feature of Lebanese topography is the alternation of lowland and highland that run north-south. Lebanon presents a Mediterranean climate with four


deforestation and recent large forest fires in the country. The assessment of landcover influence on this soil showed the prevalence of forest/shrub vegetation on Leptosols. Luvisols are distinguished by the prevalence of natural vegetation with lower alteration rates to cultivation. Cambisols, Calcisols, Fluvisols and Vertisols are spread all over Lebanon on level and slightly slopping lands and show variability in depth with dominance of deep and very deep units with prevailing annual crops and grape cultivation. The moderately deep man-made Anthrosols are found on terraced slopping lands and mainly used for fruit trees and olive cultivation.

2. Concept and Method

853

Areas with ratio exceeding 0.65 were considered humid and given a score of 1 with little negative effect of climate on sensitivity to desertification. Climate effect increased proportionally with the reduction of the AI ratio with maximal impact at < 0.05 range. 2.2 Soil Quality Index The SQI (soil quality index) was the product of five parameters: PM (parental material), S (slope), SD (soil depth), T (texture) and OM (organic matter) content (Eq. (1)). For this purpose, the soil map at 1:50,000 scale [19] was used to assign scores to different soil types resulting in more mapping units reflecting local soil diversity. Consequently, soil depth, texture, and slope

classes

were

modified

and

additionally

The methodology included assessment of SEQI

segmented to match the complex orography of the

(socioeconomic indicators) such as living conditions,

country. Given the important role of OM in soil water

literacy rate, dwelling and health conditions, access to

retention and the soil/vegetation resilience to drought,

clean water and sewer network, means of heating and

the methodology was enriched by the inclusion of soil

cooking that were spatially mapped at local level.

organic matter content. The SQI was assessed

These indicators were integrated with the physical

according to the following formula: SQI = (PM × S × T × D × OM)1/5 (1) The PMs were subdivided into coherent, moderately coherent and soft to friable. Given the large presence of eroded soils on slopping and steep lands and the importance of soil depth for water retention and root penetration, the SD (soil depth) layer was subdivided into five classes (Table 2). These were given the score of 1 (SD > 150 cm), 1.25 (100-149 cm), 1.50 (50-99 cm), 1.75 (10-49 cm) and 2 (< 10 cm), respectively.

factors. Each bio-physical factor contributing to land sensitivity to desertification was classified into five ranges and was assigned a score ranging from the least negative influence (1) to slight effect (1.25), moderate impact (1.5), high impact (1.75) and very high impact (2). These indicators were summarised as the CQI (climatic quality index), SQI (soil quality index), VQI (vegetation quality index) and SDI (sensitivity to desertification index). 2.1 Climatic Quality Index Climatic data were retrieved from 48 stations spread throughout Lebanon and the geo referenced data were converted into a spatial climatic index map by krigging. The spatially plotted climatic indicator was analyzed using the AI (aridity index) of the UNEP (United Nations Environmental Program). The AI is a ratio of mean annual precipitation to mean annual potential evapotranspiration. It comprises five classes (Table 1).

2.3 VQI (Vegetation Quality Index) Classes of the new land cover/land use map of Table 1 Vulnerability of actual climatic zones to desertification. CQI = P/PET

Climatic zones

Scores

< 0.05

Hyper arid

2

0.05-0.20

Arid

1.75

0.20-0.50

Semi-arid

1.50

0.50-0.65

Dry sub humid

1.25

> 0.65

Humid

1

854


Table 2 Adopted classification and association of scores for main soil physico-chemical parameters. Slope gradient 45

Depth (cm) > 150 100-149 50-99 10-49 < 10

OM (%) >6 4-5.9 2-3.9 1-1.9 1.75), occupy the rest of Lebanon except for the north-eastern part where the lowest aridity index is found. Quantitatively, more than 78% of Lebanon resides in a semi-arid and arid climate and witness old human

pressure through deforestation, overgrazing and land use changes leading to soil erosion and enhancing flush floods. Human activities in the region go back into history with the oldest record of forest clearance by humans in the Ghab valley, Syria, dating some 11,000 years ago [30]. Dry sub-humid climate covers a small area of 14.75%, while the humid and per humid zones form 6.9% and 0.2% of the territory, only. Humid Lebanese areas are predominantly located on stable, non eroded territories [31], but these bright spots are still threatened by sheet and gully erosion observed in the unstable lands with soil losses estimated elsewhere to be 10 to 40 times faster than soil renewal rates [31]. 3.2 Status of Vegetation Cover The vegetation cover was classified by its contribution to protect or expose the soil to land degradation. Lower quality vegetation occupies the


857

km

Fig. 4

Vegetation quality index map of Lebanon.

middle and high peaks of Mount Lebanon as well as the lower and middle heights of the eastern chain of Anti-Lebanon with some dispersed patches in the south (Fig. 4). This can be explained by the important mixture of grasslands and field crops with low resistance to desertification and low protection from erosion, beside the occurrence of wooded land with high risk of forest fire. Vegetation with moderate quality (30% of the total area) is found mainly in the Bekaa valley and south Lebanon. Ecosystem fragility is caused by the mismanagement of permanent crops, scrublands and terraced fruit trees with moderate resistance to desertification, erosion and moderate susceptibility to fire. A significant part of the country (35% of the total area) has high quality vegetation with low sensitivity to desertification. It is covered mainly by dense forests, dense shrubs and well maintained terraced fruit trees. Starting from 1975, the country witnessed a civil war

followed by an economic crisis and recession in the agricultural sector leading to land abandonment, forest partial invasion into mountainous agricultural lands. Such combined effects of biophysical and anthropogenic factors contributed to reduced erosion rates and partial recovery of natural vegetation [32]. In general, more than half of the country benefits from high and moderate quality vegetation and almost one fifth is covered by low quality vegetation. However, with increasing human intervention and provoked fires, the probability of forest fire is beyond the expected natural susceptibility assessment. 3.3 Status of Soil Degradation Different soil quality classes are found in Lebanon. High and very high quality soils dominate over 65% of the territory. They correspond to Fluvisols, Cambisols, Luvisols and terraced Anthrosols [19] developed over moderately coherent to coherent parent materials. They have deep to very deep soil profile with loamy-clay

858


texture and relatively high organic matter content reaching 4% and rarely 6%. The deforested central high mountains present good soil quality despite the limitation in depth due mainly to geomorphologic position, heavy texture and more importantly the relict high organic matter content inherited from old forest cover. Low soil quality is found in the Anti-Lebanon and in the middle part of the country accounting for 11% of the area (Fig. 5). Shallow and highly calcareous soils named Lithic Leptosols and Petric Calcisols, considered very low quality soils, occupy about 5% of the area. High gravely and light textured or calcareous deep soils with moderate quality and/or restricted drainage conditions such as Regosols, Arenosols, Leptosols, Vertisols and Gleysols are more frequently found (about 19% of the area). However, productive soils are under tremendous pressure from sealing due to chaotic urban expansion leading to the loss of more than 60% of prime coastal lands [8]. Human pressure is reflecting also on the soil

Fig. 5

Soil quality index map of Lebanon.

groundwater contamination and salinity build-up [11, 33], two main determinants affecting land degradation both in dry and relatively humid Mediterranean areas [34]. Human induced soil degradation in Lebanon affects ecosystem resilience which can increase the sensitivity to desertification. The situation could worsen due to some management policies accompanying modern intensive farming. There are many examples where certain crops or practices lead directly to some form of degradation [35]. Subsidies for sugar beet cultivation in Lebanon for instance resulted in an extensive use of non treated sewage water for irrigation in the water scarce Bekaa region, accompanied by soil pollution problems. Consequently, instead of subsidizing wheat, doing this for sugar beet resulted in profound depletion of soil water reserves, development of deep cracks and compaction of soil layers. Recent governmental policies addressed participatory rural appraisal which was used to describe the indigenous agroecological zoning and


local soil classification. Pressure on rangeland and shrinkage of grazing lands was attributed to the expansion of orchards and reduction of small ruminant flocks [36]. The drivers of land use change were linked to higher profit and less time/labor demands. The significant increased number of pastoralists/farmers and managed areas indicate the possibility to improve rangeland management in the extremely dry Lebanese regions [37] as adaptation strategy to alleviate the impact of desertification. 3.4 Human Impact on Land Degradation Socioeconomic data showed that the lowest living conditions were found in north Lebanon, Bekaa and south Lebanon. These areas are located in 16 casas out

of 26 and represent more than 66% of the nation’s territory. Typical for them is low water supply, poor education, dwelling and income, which are the lowest in the country (Fig. 6). Beirut and Mount Lebanon fall in the very high living conditions class. However, these high quality living conditions for the population of central western coastal Cazas exert moderate, but significant pressure, on land and water resources and can affect the quality of environment. Very high and high socioeconomic conditions are met in less than half of the country (39%). Lower standard conditions, found in north and south Cazas, occupy 30% of the territory, while very low socioeconomic standards cover almost 9% of the remaining territory.

km

Fig. 6 Socio-economic quality index map of Lebanon.

859

860


Throughout the available literature on the integration and role of socioeconomics in the desertification process, a multitude of methodologies relying on several complex indicators to assess socioeconomic can be discernible. Some studies discussed the need for more integrated complex combination of indicators and factors like poverty, market conditions, value of land use, inequality, migration and political situation [5, 38-40]. Other workers emphasized participatory land management [41, 42] and involved technical assessment of natural indicators of soil erosion as major factors of land degradation [4]. Poverty remains the main actor in this field of studies from a socioeconomic point of view and constitutes a major cause and is a consequence of land degradation processes. However, the relationship between income growth, carbon emissions and ecological footprint

Fig. 7 Sensitivity to desertification map of Lebanon.

impact on environmental degradation should not be overlooked when assessing its possible effect at the local scale [43]. Efforts against land degradation and desertification could be successful if the right policy instruments are activated to deal with natural resources management and conservation [44, 45]. 3.5 Status of Desertification in Lebanon Areas prone to desertification, which belong to the most affected categories, i.e., moderate, high and very high sensitivity classes, represent 57.28% of the territory (Fig. 7). Among these, the moderate sensitivity class covers 16.8%, high and very high sensitivity classes cover 23.20% and 17.28% respectively and the remaining 26.17% of the land is under low and very low sensitivity to desertification (Table 4). More sensitive areas can be considered as


861

Table 4 Sensitivity to desertification on the Lebanese national level. Class 2012 Projected area (km2) % 2002 %

Very low

Low

Moderate

High

Very High

Urban/ rocks

Total

1299.0 12.7

1372.9 13.4

1715.3 16.8

2368.9 23.2

1764.0 17.3

1690.7 16.6

10210.8 100.0

0.2

5.7

26.4

48.1

11.2

hot spots requiring immediate attention and a participatory approach to elaborate adaptation and mitigation measures and alleviate land degradation negative effects. Areas with moderate sensitivity to desertification need preventive and curative measures to improve their status while low and very low sensitivity to desertification areas or the “bright spots” require attention to protect and prevent any deterioration in the fragile balance between natural components and human induced factors. The Lebanese coastal areas with a dense population and high water demand need immediate measures and stakeholder’s involvement (Ministries, Municipalities, Association of farmers, NGOs) to improve the quality of groundwater. The fundamental pressure induced by high population growth, rapid urbanization and deficit water supply resulted in excess pumping from coastal aquifers causing the deterioration of water quality with serious impact on public health [46] as salinity built up. Interestingly, more than 98% of the farmers in affected areas are willing to pay to preserve the groundwater from further deterioration and implement modern irrigation systems to improve water use efficiency and distribution [47]. South Lebanon and Nabatiyeh cazas, and the north starting from the coast until high inlands including Akkar and Bekaa Cazas, notably Baalbeck are classified as high and moderately sensitive to desertification. Despite the relatively low socioeconomic standards, a small patch on the northern coast shows low sensitivity to desertification due to better quality vegetation and dominantly high quality soil. Given the general low value of current land use consisting mainly of rainfed extensive olive cultivation

8.6

100.0

with little net return, this human factor can exacerbate the situation, if the olive oil production and oil marketability are not improved. The middle western part of the country shows an overriding low and very low sensitivity to desertification. The climate of this area is sub-humid and humid with a mixed soil quality dominated by high and moderate quality vegetation and population having high and very high socioeconomic conditions. The two southern governorates, south and Nabatiye, are characterized by a mixture of sensitivity to desertification ranging from moderate to very high due to the prevailing semi-arid conditions and the mixed quality of the soil and vegetation covers. The northern part of the eastern mountain chain or Anti Lebanon shows very high sensitivity to desertification potentially originating from the prevailing arid climate and the low quality soil and vegetation cover. Low living standards in the rural marginalized cazas must receive due attention as the average income in the agricultural sector is 200$·month-1 versus an average income of 335$·month-1 for the commercial sector and 535$·month-1 for the insurance and financial services [21]. In a country where more than 70% of the households use diesel for heating, chaotic wood cutting is observed in inland and mountain rural areas notably in response to higher fuel prices. Earlier observations showed that the forest cover in the Bekaa area has declined dramatically during the last 50 years resulting in intensive erosion of marginal lands [7]. A brief comparison of the current sensitivity to desertification map with the national desertification prone areas map of 2003 [33] shows comparative general trends with fine-tuning of previous assessment

862


due mainly to the use of larger scale updated soil and vegetation cover data. Areas with high land quality and better resilience and therefore low sensitivity to desertification were larger in our study (26.17% versus 5.7% in the old assessment), while the area of moderate sensitivity class was 16.2% against 26.4% and the highest sensitivity areas were 40.48% compared to 54.3%.

conditions if appropriate policies and management practices are implemented. Results can serve as a tool to elaborate participatory plans for potential adaptation and mitigation measures in hotspots and preventive measures in bright spots. The methodology could be repeated for monitoring the state of desertification in the country and extended in other countries of the Mediterranean region.

4. Conclusions

Acknowledgments

Increasing human pressure on limited natural resources in Lebanon justified a new desertification risk assessment based on the integration of biophysical and socioeconomic conditions. This work was necessary to analyze desertification trends at local level and adjust the national action programs to combat desertification.

The

current

sensitivity

to

desertification for the country was estimated using the CQI (climatic quality index), SQI (soil quality index), VQI

(vegetation

quality

index)

and

SEQI

(socioeconomic quality index) categorized into five sensitivity classes ranging from very low (scored 1) to

This study received support from the EU funded INCAM project coordinated by the CNRS Lebanon in partnership with the CIHEAM-IAM, Bari, Italy and the IRD Toulouse, France and from the Master of Science Programmes offered by the Mediterranean Agronomic Institute of Bari. The authors recognize the review of the article by T. Atallah, the logistic support from M. Hamzé. A. Pancera (EU Research Program and Policy Officer) and the technical assistance of R. Francis.

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[2]

way that the soil layer (SQI) features get the attributes of other layers. Using this approach beside the

[3]

involvement of detailed soil and updated vegetation data substantially improved the assessment process. Overall, results showed the spatial distribution of zones with very low (12.72%) and low (13.45%) sensitivity to desertification to be concentrated in Central Mount Lebanon, north-west and south-east Lebanon. The areas with moderate, high and very high sensitivity are spread in north-eastern and southern parts of the country representing 16.80%, 23.20% and 17.28%, respectively. Despite the important effect of climate and low living conditions on land degradation, the good quality soil and vegetation cover still possess the relative capacity to buffer human pressure and provide hope for better environmental and living

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Agriculture, Lebanese Republic, Lebanon, Central Administration of Statistics CAS Web site, http://www.cas.gov.lb (accessed Mar. 13, 2012). P. Sanlaville, Geomorphology of Coastal Lebanese Region, Publications of the Lebanese University, 1977, p. 405. A Framework for International Classification and Communication, World Reference Base (WRB) for Soil Resources, World soil resources report 103, FAO, Rome, 2006. G. Faour, Towards a Sustainable Mechanism for Forest Fires Fighting in Lebanon, National report, Beirut, 2005, p. 27. T. Masri, C. Khater, N. Masri, Ch. Zeidan, Regeneration capability and economic losses after fire in Mediterranean forests-Lebanon, Lebanese Science Journal 7 (2006) 37-47. Living conditions of households in Lebanon [Online], http://www.undp.org.lb/programme/pro-poor/poverty, /poverty in lebanon/molc/main.html) (accessed July 27, 2012). ESRI Web site, 2012, http://resources.esri.com/help/9.3/arcgisdesktop/ com/ gp_toolref/coverage_tools/how_identity_coverage_works .htm (accessed June 2012). M. Dragan, T. Sahsuvaroglu, I. Gitas, E. Feoli, Application and validation of a desertification risk index using data for Lebanon, Management of Environmental Quality 16 (2005) 309-326. Y. Enzel, R. Amit, U. Dayan, O. Crouvi, R. Kahana, B. Ziv, et al., The climatic and physiographic controls of the eastern Mediterranean over the late Pleistocene climates in the southern Levant and its neighboring deserts, Global and Planetary Change 60 (2008) 165-192. Y. Yasuda, H. Kitagawa, T. Nakagawa, The earliest record of major anthropogenic deforestation in the Ghab Valley, northwest Syria: A palynological study, Quaternary International 73-74 (2000) 127-136. D. Pimentel, Soil erosion: A food and environmental threat, Environment, Development and Sustainability 8 (2006) 119-137. N. Bellin, V. Vanacker, B. van Wesemael, A. Solé-Benet, M.M. Bakker, Natural and anthropogenic controls on soil erosion in the internal Betic Cordillera (southeast Spain), Catena 87 (2011) 190-200. T. Darwish, I. Jomaa, M. Awad, R. Boumetri, Preliminary contamination hazard assessment of land resources in Central Bekaa Plain of Lebanon, Lebanese Science Journal 9 (2008) 3-15. L. Perini, S. Bajocco, T. Ceccarelli, M. Zitti, L. Salvati, A process-based assessment of land vulnerability: Italy as a case-study, in: 2nd International Conference: Climate,

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D

DAVID

PUBLISHING

Construction and Demolition Debris Management for Sustainable Reconstruction after Disasters: Italian Case Studies Carla Furcas and Ginevra Balletto Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Cagliari 09123, Italy Received: February 1, 2012 / Accepted: March 10, 2012 / Published: July 20, 2012. Abstract: The Italian earthquakes of recent decades created an emergency situation that required immediate post-earthquake reconstruction policies, which led to an increase in the demand for construction minerals. In particular, extraction in active quarries has been intensified, and new quarries opened according to extraordinary procedures notwithstanding current regulations. The objective of this work is to investigate the consequences that a seismic event may produce on both the built-up environment, i.e. the totality of urban and suburban settlements and infrastructure, and the natural environment, which is often compromised by hasty emergency procedures aimed at mineral extraction. As a result, correct evaluation of the demand for minerals and the recycling of earthquake debris are the fundamental elements of coherent post seismic reconstruction, by means of which post-earthquake policies could be reconciled with environmental protection. Key words: Reconstruction, construction and demolition, waste, debris, recycling, earthquake. 

1. Introduction

Italy is one of the European countries with the highest risk of earthquakes, the areas potentially affected extending throughout the country: in particular, the region of Friuli-Venezia Giulia, the central-southern Apennines, the Calabrian and Tyrrhenian margin and south-eastern Sicily [1]. Some 23 million Italians out of a population of 60 million (38%) reside in areas of high seismic risk, and 4,610 municipalities out of 8,112 (56.8%) are located in seismic zones [2]. The earthquakes occurring in Italy usually create extensive damage, due to both geomorphological conformation and incorrect use of the territory, characterized by an excessively high concentration of urban settlements. The procedures for post-earthquake reconstruction,  Corresponding author: Carla Furcas, research fellow, main research fields: restoration of mining sites, evaluation of the demand for natural resources and construction & demolition (C&D) waste recycling policies. E-mail: [email protected].

i.e. the removal of debris, the demolition of unsafe buildings, and their reconstruction [3], lead to an inexorable increase in the requirements for construction minerals. In particular, the demand for aggregates (sand, gravel and crushed stone) intensifies, because they can be used either in road filling, railway ballast or armour stones, or in the production of glass (quartz sands), ready-mixed concrete (made of 80% aggregates), pre-cast products, asphalt (made of 95% aggregates), etc.. Such structures are all examples of the urban and suburban settlement and infrastructure usually needed to rebuild after a seismic event. By the recycling process, the part of the materials needed for reconstruction activities can be obtained. Therefore, the extraction of natural minerals could be reduced. Recycling of C&D (construction and demolition) waste is becoming a significant resource in some countries. For example, the Netherlands and Japan recover almost all the concrete from their construction waste; in 2007 Germany recycled 89.2%

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Construction and Demolition Debris Management for Sustainable Reconstruction after Disasters: Italian Case Studies

of C&D waste [4]. As regards European recycling policies, while in some countries the market for recycled aggregates is on the increase, in other EU states C&D waste is rarely re-used. According to the European Aggregates Association [5], nearly 6% of the European aggregates demand is covered by recycled aggregates. Recycled aggregates are generally composed of crushed asphalt pavement, originating from road paving and construction activity, and crushed portland cement concrete, from C&D debris [6]. By more extensive use of recycled aggregates, greater environmental conservation and protection could be attained, reducing the extraction of natural aggregates and thus limiting the opening of new quarries. In order to achieve this objective, the debris from catastrophic events may be included in a recycling process, becoming a resource. Review of the literature on the subject identifies the major benefits of recycling disaster waste [7], including:  reduction in landfill space used;  reduction in the amount of minerals used in reconstruction;  revenue from recycled aggregates;  reduction in transportation costs for both natural materials and debris;  job creation (for developing countries in particular). Several case studies document this recent attention to the recovery of debris after catastrophic events, e.g. the deconstruction (the hand dismantling of buildings) in post-Katrina New Orleans [8]. This case aimed at reclaiming building materials from some of the 275,000 destroyed homes after the US Gulf Coast hurricane season of 2005. The results of the deconstruction program showed salvage rates varying from 28% to 62% of individual building weight, reaching a total project recovery rate of 48%. Moreover, the program demonstrated that it was possible to salvage enough material to build three new homes out of four destroyed ones. In this context, our work aims to investigate how the

emergency situation could be managed in order to mitigate the potential damage caused by a seismic event and the subsequent recovery and rebuilding process. Therefore, the amount of the waste resulting from specific Italian earthquakes has been assessed, with suggestions regarding potential recycling.

2. Emergency Management 2.1 Legislation and the Role of the Authorities In Italy emergency management is entrusted to an organization called the National Civil Defence, whose responsibilities for forecasting, prevention, rescue and return to normal living conditions are stipulated by Law

225,

published

in

1992.

Following

the

Constitutional Law No. 3 (2001), the state establishes the guidelines for civil defence, whereas local authorities (the Regions, the Provinces, the Prefect, the Mayor and the Municipalities) draft the programs for the prediction and the prevention of risks and the practicalities in cases of emergency. However, the ability of ordinance is provided by Law 225 as an operational tool, which may derogate from both local and national legislation, except for EU procurement procedures for public works contracts. The ability of ordinance is attributed to the Prime Minister or the Minister of the Interior, or commissioners delegated by them.

By

using

accelerated

procedures,

such

ordinances may allow an intensification of quarrying activity owing to the increased demand for building materials.

In

addition,

the

ordinances

follow

extraordinary procedures under the responsibility of the Prime Minister or his delegates instead of the usual formal procedures related to mining, which would normally be a regional responsibility. In this specific context, waste recycling is an initiative of great value which aims to mitigate environmental risks and to increase sensitivity to environmental protection. In Fig. 1, the location of the Italian case studies analysed is reported.


Fig. 1

Location of the case studies.

2.2 Case Studies 2.2.1 Friuli-Venezia Giulia Earthquake (1976) On Thursday, May 6, 1976, a quake measuring 6.4 on the Richter scale and on September 15, 1976, another strong quake struck the Friuli-Venezia Giulia region. The emergency management was entrusted to a special commissioner who had the ability to take

867

whatever measures were deemed appropriate and necessary (Law 730, 1976), notwithstanding the rules in force. During the rebuilding process, the “new town” solutions (the reconstruction of houses in new areas) were not welcomed by the population, who preferred urban solutions more similar to those already existing. For example, for the reconstruction of the Cathedral of Venzone (Province of Udine, Friuli-Venezia Giulia), while civil engineers wanted to build a new church, the inhabitants insisted on restoration according to the original configuration. Thus, they recovered 7,650 stones of the Cathedral and re-used them for its reconstruction, thus demonstrating the feasibility of converting debris into a resource. Because of the length of time since the event, quantification of debris resulting from the earthquake shown in Table 1 is difficult and underestimated. Moreover, from the comparison between the number of destroyed houses with those rebuilt, it can be noted that 12,000 new homes were built. This indicates that many damaged buildings were demolished instead of being scheduled for renovation works. In fact, demolitions originated from commercial interests, because the building firms charged the standard price for the

Table 1 Earthquake data for the case studies [1-3]. Friuli-Venezia Giulia (1976) Area of interest Dwellings

Population

about 5,500 km2

Victims

989

Surface

Homeless

100,000

Italian regions Friuli-Venezia involved Giulia

Destroyed/ damaged

18,000/ 75,000

Reconstructed 30,000

Debris Amount

188,741 cubic metres

Removal time

1 year

Irpinia (1980) Population Victims

2,914

Homeless

280,000

Population

Area of interest

Dwellings

about 17,000 Destroyed/ 70,000/ km2 damaged 30,000 Campania, Italian regions Basilicata, Reconstructed 54,161 involved Puglia Abruzzo (2009) Area of interest Dwellings

Surface

about 5,000 km2

Victims

308

Surface

Homeless

67,500

Italian regions Abruzzo involved

Destroyed/ damaged

24,325/ 12,296

Reconstructed 8,035

Debris Amount

132,720 cubic metres

Removal time

2 year

Debris Amount

2,650,000 cubic metres

Removal time

Still ongoing

868


removal of debris of 1,900 lire/m3 [9], corresponding to about 2.3 $/m3, according to 1976 yearly average exchange rates. 2.2.2 Irpinia Earthquake (1980) On November 23, 1980, a quake of 6.8 on the Richter Scale took place in a zone encompassing the Campania, Basilicata and Puglia regions. Due to the vastness of the area affected and to the large number of municipalities involved (687), the commissioner appointed a special emergency structure subdivided into four hierarchical levels up to the municipal level. Law 219 (1981) set out all the arrangements for the reconstruction. The amount of earthquake debris is difficult to assess due to the Camorra infiltration in the removal activities (Parliamentary Anti-Mafia Commission, 1993). Despite this, there were some interesting cases of recovery: the first concerns the town of Valva (Province of Salerno, Campania), in which the municipal government rebuilt the old town by expropriating buildings, providing a recovery plan and relocating the debris piece by piece. The second case, more recently, pertains to the Integrated Project “The Abbey of Goleto” (2005-2008). The renovation works involved the re-use of the debris, which consisted of both blocks and rubble, which were recycled for the production of lime and pozzolana used for mortar, plaster, concrete screed and flooring [10]. In this case the demolition of damaged buildings was again preferred: in particular, Law 219 established a family-unit contribution for the reconstruction of the houses to be demolished, encouraging demolitions rather than renovation works. This resulted in growing pressure on the environment: in fact, not only the amount of debris transported to landfill, but also the demand for building materials increased. 2.2.3 Abruzzo Earthquake (2009) On April 6, 2009, an earth tremor measuring 5.8 on the Richter Scale shook the Abruzzo region, in particular the province of L’Aquila. To ensure rapid implementation, the emergency decree passed by the Italian Government (Decree No. 39 of 2009, “Abruzzo

Decree”) gave the delegated Commissioner the tasks of identifying the areas where new houses, infrastructure and services should be built, and of overseeing their construction. These areas were located by an emergency decree (Ordinance of the President of the Council of Ministers No. 3811, 2009) as an exception to the existing urban and landscape regulations. Some recent studies [11] show how the built-up area increased either in previously unbuildable areas (because of landscape and historical-architectural constraints), or in agricultural zones (reduced buildability). The zone also includes the National Park of Gran Sasso and Monti della Laga, which were previously subject to landscape constraints. The Abruzzo Decree sets provisions for the management of the debris resulting from the collapse and the demolition of buildings: it has been assimilated to municipal waste, and the municipalities must deal with its removal, collection, transportation, recovery and disposal. However, the mayors could not proceed with the complete removal of debris because they said that they lacked the technical and economic resources. Thus, there is still uncertainty in the quantification of debris and in its removal. Recently (February 1, 2010), the criterion of “solidarity redistribution”, which identifies debris storage sites in neighbouring territories, was proposed to the mayors. A specific project has also been agreed that schedules in 24 months the definition of both the quantification and the treatment of the debris, in collaboration with the University of L’Aquila. 2.3 A Recycling Experience: The Activity of the Umbria Region The earthquake that struck a zone between Umbria and Marche on September 26, 1997 is an interesting example of the management of the debris. There were 70,252 damaged buildings, and in the worst affected municipalities more than 1,580 demolition orders were issued [12]. The Umbria Region promulgated the


Directive on “Removal of debris, demolition of buildings and materials recovery” (1998), which defined the role of the local authorities and set controlling the number of demolitions and the re-use of debris as targets. In addition, the region established that each municipality must re-use at least 50% of the materials recycled from the earthquake debris in the reconstruction of public and/or private civil works. The timeliness in undertaking these procedures was possible because a policy of recycling of C&D waste had been initiated by the Regional Government even before the earthquake, with the “Plan for waste management” (1987), which focused on the recovery of “mixed waste resulting from demolition”. In this perspective, the amount of aggregates coming from the debris was assessed, taking into account the quantities resulting from the reconstruction of the destroyed buildings. Methodologically, the estimate was obtained by making a first assessment of building types (masonry buildings, typical of medieval city centres). For each building the amount of debris expected from normal demolition operations is 20%-25% of the volume of the whole building, estimated at 700-750 cubic metres. Subsequently, a data check on some demolitions carried out in one of the municipalities affected, Nocera Umbra, was undertaken. An average of 300 cubic metres of debris for each building was then defined, a total of 474,000 cubic metres. Moreover, an estimate of the waste deriving from the reconstruction of the damaged buildings, for which planning permission had been given (until December 31, 2001), was made; this assessment amounts to 429,000 cubic metres. Consequently, the quantification of the earthquake waste is 903,000 cubic metres. Many entrepreneurial activities dedicated to recycling were undertaken. These activities, as a result, led three years after the earthquake (December 31, 2001) to the production of 189,362 cubic metres/year of recycled aggregates, among which 103,333 cubic metres/year or 55% of the total were sold. The recovery rate of the debris conferred consisted of inert materials and iron,

869

with ranges from 96% to 98% [11].

3. Potential Waste Recycling in Abruzzo 3.1 Preliminary Comments In order to evaluate in a recycling perspective the recent earthquake management in Abruzzo, the feasibility of the methodology applied in Umbria was investigated. The initial assumption was to consider that the construction typologies of the Umbrian towns affected by the earthquake are similar to those of the towns of Abruzzo, i.e. medieval town centres mostly composed of single-family buildings with load-bearing masonry. In order to analyse the damages reported in the historic centre of L’Aquila, the area of the city that suffered major damage following the quake, the Seismic Engineering Operational Unit DISAT-UOIS on days April 24, 25 and 26, 2009 carried out an inspection which mainly showed three-storey edifices in load-bearing masonry as residential building typologies [13]. In addition, the 14th General Census of Population and Housing [14], subdividing the residential buildings into three typologies of one, two, three or more dwellings, also supports this hypothesis, as shown in Table 2. 3.2 Procedure for the Quantification of the C&D Debris Generated in the Seismic Event Assuming that for the building typologies of the Abruzzo towns affected by the earthquake the amount of debris expected from ordinary demolition activities is 20% of the total volume of a typical building of the zone, estimated at 700 cubic metres, a first assessment of the debris was made, resulting in 3,405,500 cubic metres. It is important to note that such evaluation only takes into account the 24,325 buildings destroyed by the earthquake, leaving out the estimation of debris from the damaged ones (certainly not zero) because of

870


crushing, 1% of light fraction (paper, plastic, wood, etc.) which goes to disposal and 0.1% is ferrous material. The case study of the recycling plant of Santo Stefano Magra in the Province of La Spezia, Liguria [18] confirms that stationary installations could reach 95% efficiency, as well.

quantification difficulties. Another assessment quantifies the debris as 2,650,000 cubic metres [3]. Currently, this assessment is under redefinition by the University of L’Aquila. In order to apply the “Umbria methodology” to Abruzzo, quantification of the recyclable waste is necessary. In fact, because of the various origins of such waste, the differing local building techniques, the local availability of raw and building materials, etc., the composition of the C&D waste is rather changeable. In order to evaluate the amount of recyclable waste, the average percentage compositions of C&D waste in Italy is shown in Table 3 [15, 16]. Hence, in Italy the average recyclable fraction of C&D waste consists of a percentage varying from 90% to 95%. Review of the literature on the subject suggests that from such amounts all masonry and concrete waste can theoretically be recycled and re-used, in particular when the recycled materials satisfy the given technical specifications and the process is economically competitive [17]. In practice, especially through a stationary recycling plant which leads to products of higher quality and homogeneity, it is possible to reclaim about 90%-95% of C&D debris. For instance, the Plan for Waste Management in Sicily (2002) indicates that the efficiency of these plants can reach about 95%. The remaining 5% consists of 4% of natural earth, separated before

4. Results and Discussion Given the two previous evaluations of the C&D earthquake debris in Abruzzo, and assuming that the recyclable fraction is about 90% of all debris, from which the 5% of light fraction and ferrous material should be subtracted, the obtainable amount of recycled aggregates could be assessed. This amount in the first case consists of 2,911,703 cubic metres (estimated ex-Umbria methodology) and in the second of 2,265,750 cubic metres (estimated ex-ITC-CNR). These recycled aggregates could be re-used directly in the reconstruction process. Although the extraordinary demand for building materials in the Abruzzo region following the seismic event is difficult to quantify, presumably it is higher than the ordinary annual requirements, estimated as 4 cubic metres/inhab [16]. The next step is to quantify the extraordinary demand for building materials due to the reconstruction process in the regional capital of Abruzzo, L’Aquila. A review of the literature identifies several approaches that could be undertaken, among which it is

Table 2 Comparison between construction typologies (%) of Umbria and Abruzzo. Regions Umbria Abruzzo

Residential buildings 1 dwelling 2 dwellings 3 or more dwellings Among which: more than 10 dwellings Total 25 24 51 20 100 31 19 49 22 100

Non residential buildings 142 140

Table 3 Average percentage compositions of C&D waste in Italy. Jakobsen evaluation Waste typology % weight out of the total Concrete 30 Bricks 50 Asphalt 5 Excavation 6-10 Other (paper, metals, wood, etc.) 4.60-5.40 Total recyclable (approximately) 91-95

European Demolition Association evaluation Waste typology % weight out of the total Concrete 45 Bricks 35 Asphalt 10 Other (paper, metals, wood, etc.) 10 Total recyclable (approximately) 90


871

Table 4 Recycling potential of the earthquake debris in Abruzzo (cubic metres if unspecified) [11, 13, 17]. Potential annual Abruzzo Potential Potential amount of 2003 per Abruzzo Potential annual Abruzzo amount of Abruzzo amount of aggregates from capita earthquake amount of aggregates Population annual earthquake recycled recycled recycled output of debris from recycled of Abruzzo output of debris aggregates aggregates earthquake aggregates (Umbria earthquake debris (2003) aggregates (CNR-ITC (Umbria (CNR-ITC debris (%) (cubic methodology (%) (CNR-ITC (2003) assessment) methodology assessment (Umbria meters/ assessment) assessment) assessment) ) methodology inhab) assessment) 1,285,896 5,200,000 4.04 3,405,500 2,650,000 2,911,703 2,265,750 56% 44%

possible to mention three main groups [19, 20]: (1) the assessment of demand for aggregates based on statistical aggregates; (2) the assessment of demand for aggregates in reference to the forecasts of the urban plans; (3) the assessment of the consumption and the production of aggregates. In post-earthquake reconstruction, the second approach seems to be the most appropriate. It is based on an evaluation of the possible consumption of mineral resources referring to the forecasts of planning instruments. In this specific case, appropriate planning tools are desirable to provide an assessment of the destroyed buildings and infrastructures, and therefore such urban plans can estimate how many of these need to be reconstructed. According to these forecasts, the quantification of the extraordinary demand for aggregates is then possible, and consequently the modalities

to

find

the

materials

needed

for

building materials in the occurrence of seismic events;  the primary location of the storage, treatment and recovery facilities of the debris. On an international scale, the need to plan for disaster debris can be traced back to the USEPA’s (United States Environmental Protection Agency’s) “Planning for Disaster Debris” [21], updated in 2008 [22]. Although many other states outside the US have recognised the importance of planning disaster waste, few guidelines exist, and they are mostly based on the USEPA’s guidelines [7]. In the absence of such tools, observations on the re-use of recycled aggregates in the case of Abruzzo could be made, considering that they could be used to satisfy the ordinary annual demand for aggregates in the Abruzzo region, with percentages that vary from 44% to 56%, depending on the two different estimates, as shown in Table 4.

5. Conclusions

reconstruction, partly deriving from natural resources

This paper studies the possibility of recycling the

and partly from the recycling of C&D debris, can be

debris resulting from catastrophic events such as

planned. However, presently there is a lack of urban

earthquakes. Since post-seismic reconstruction results

plans which could allow us to make predictions and

in increased demand for building materials, the re-use

estimates of the requirements for the rebuilding process

and the recycling of C&D debris has interesting

in the city of L’Aquila. For this purpose, it would be useful for the municipalities located in seismic areas to establish plans for the recycling of debris involving:  analysis of building typologies, with information on materials and construction techniques, and indications of the buildings most at risk;  assessment of the extraordinary demand for

potential. In order to recycle the greatest quantity of debris in the shortest time, firstly proper quantification of the available C&D waste and secondly correct assessment of the demand for building materials are appropriate. The literature on the subject suggests the use of stationary recycling facilities, which guarantee a reclaim of up to 95% of the materials processed. The waste management methodology of the Umbria Region

872


after the 1997 earthquake at first quantified the

References

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[1]

demolition activities, and then checked the data with the amounts obtained in some actual demolitions. This method allowed us to quantify the debris in the Abruzzo case study, and also the derived potential amount of recycled aggregates. In particular, it has been demonstrated that the recycled aggregates would be able to cover the ordinary annual demand for aggregates of the Abruzzo region, in a percentage varying from 44% to 56%. In order to make a proper quantification of the extraordinary requirements for building materials due to the reconstruction process, further studies are required. In fact, the next step of the research is to quantify the extraordinary demand for building materials due to the reconstruction process in the regional capital of Abruzzo, L’Aquila. The assessment of demand for aggregates in reference to the forecasts of the urban plans seems to be the most appropriate approach. Since an updated urban plan for L’Aquila is still lacking, the estimation of the extraordinary requirements for minerals is difficult, but it assumes great relevance because it could allow the debris to be re-used directly in the reconstruction process. Acting in this way, the municipalities located in seismic areas would be equipped with plans for the recycling of the debris including preliminary assessment of the building typologies, predictions of the extraordinary demand for building materials for the reconstruction and the primary location of the treatment facilities of the debris.

Acknowledgments This research was supported in part by the Autonomous Region of Sardinia with a grant financed by the “Sardinia PO FSE 2007-2013” funds and provided according to the Sardinian Regional Law 7/2007 “Promotion of Scientific Research and Technological Innovation in Sardinia”.

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[16]

[Online], http://www.unich.it/fusero/HTML_university/pubblicazio ni.htm (accessed June 6, 2011). M. Valentini, Management and the reuse of materials after natural disasters, 1997 Umbria earthquake, presented at XIX-SEP POLLUTION [Online], Padova, 2002, http://www.centroambiente.it/consorzio.htm (accessed June 7, 2011). L. Fanale, M. Lepidi, V. Gattulli, F. Potenza, Analisi di edifici danneggiati dall’evento sismico dell’aprile 2009 nella città dell’Aquila e in alcuni centri minori limitrofi (Analysis of buildings damaged by the earthquake occurred in the city of L’Aquila in April, 2009 and in some adjacent smaller villages) [Online], 2009, http://www.cerfis.it/it/download/cat_view/67-pubblicazio ni-cerfis.html (accessed June 13, 2011). Istat (Italian National Institute of Statistics), 14th General Census of Population and Housing, Italy, 2003. J.D. Jakobsen, Quantitativi, composizione e riciclaggio degli scarti di costruzione e demolizione in Europa (Amounts, composition and recycling of construction and demolition waste in Europe), RS-Rifiuti Solidi 6 (2) (1992) 81-84. Guide to the Mining Industry and to Recycling, 5th ed., Supplement to Quarry and Construction, Vol. 518, 2006.

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[17] N. Kartam, N. Al-Mutairi, I. Al-Ghusain, J. Al-Humoud, Environmental management of construction and demolition waste in Kuwait, Waste Management 24 (2004) 1049-1059. [18] 5-Guidelines on Construction and Demolition Waste, PHARE Twinning Project RO2004/IB/EN-07 [Online], 2007, http://old.arpal.gov.it/LG_PDF/5_LG_C&D.pdf (accessed Dec. 7, 2011). [19] G. Balletto, Sustainable planning of geo-resources: Analysis and proposals for the design of the demand for building materials—The Sardinia region as a case study, Franco Angeli Editions, Milano, 2005. [20] V. Badino, G.A. Blengini, K. Zavaglia, The estimation of the demand—Analisi tecnico—economico—ambientale degli aggregati per l’industria delle costruzioni in Italia. Parte 2°, La stima dei fabbisogni (Technical, economic and environmental analysis of aggregates for the Italian construction industry, Part 2), Geoingegneria Ambientale e Mineraria 3 (2006) 5-16. [21] Planning for Disaster Debris, Wastes Department, United States Environmental Protection Agency (USEPA), 1995. [22] Planning for Natural Disaster Debris, Office of Solid Waste and Emergency Response and Office of Solid Waste, United States Environmental Protection Agency (USEPA), 2008.


D

DAVID

PUBLISHING

Dodging the Potholes: The Spatio-Distribution and Socio-Economic Impacts of Potholes in the Residential Areas of Gweru, Zimbabwe Mutekwa Timothy, Matsa Mark and Kanyati Kudzanai Department of Geography and Environmental Sciences, Midlands State University, Gweru 9055, Zimbabwe Received: March 29, 2012 / Accepted: July 12, 2012 / Published: July 20, 2012. Abstract: Since the year 2000, the city of Gweru has had an unprecedented proliferation of unattended potholes on most of its roads. These potholes have caused discomfort to the motoring public, caused death to others and damaged vehicles. This paper presents the results of a study that sought to establish the spatial distribution of potholes and determine their socio-economic impacts in Gweru’s residential areas. Pothole location and dimensions were measured in the field whilst interviews and questionnaires were administered to vehicle owners, motor mechanic experts, drivers and the travelling public to determine their socio-economic and mechanical impacts. Stratified, convenience and purposive sampling methods were used in the selection of study streets and respondents to questionnaires and interviews. Results revealed that potholes are more concentrated in high density residential areas compared to low density areas. This is primarily due to the substandard construction of roads done in high density residential areas. Other causes of pothole formation identified during this study are poor drainage on the roads, rainfall impact, advanced age of roads, poor or lack of maintenance, type and volume of traffic as well as the effect of tree-root prying on paved surfaces. It is recommended that Gweru City Council enters into partnerships in road construction. The city should also establish fundraising projects to augment its budget. This would help ease problems of service delivery including road maintenance. Signposts can be erected to warn drivers about these hazards in the most affected streets and suburbs. It is also important that council set aside a toll-free telephone line link with road users so that areas where new potholes have been detected are quickly reported and attended to. This will not only save lives but also reduce road maintenance costs and vehicle damage. Key words: Pothole, city council, road maintenance, high-density suburbs.

1. Background  There are about 88,100 km of classified roads in Zimbabwe, 17,400 km of which are paved [1]. About 8,190 km of the road network are urban roads. These roads carry an estimated 80% to 90% of the country’s passenger and freight transport making road transport the dominant form of transport in the country [2]. Despite their importance, most roads in Zimbabwe are poorly managed and badly maintained. Although there is no accurate information about the current condition Corresponding author: Mutekwa Timothy, master, main research fields: urban transport challenges, forest governance and rural livelihoods, climate change and conservation farming, environmental pollution and control. E-mail: [email protected].

of Zimbabwe’s road network, the fact of the matter is that it has significantly deteriorated especially since the late 1990s due to the economic meltdown that characterised the period 2000-2008 leading to lack of resources particularly funding for routine and periodic maintenance [1]. Only about 24% of Zimbabwe’s entire road network was in “good” condition in 2005 and 40% was in “poor” condition [3]. The Department of Roads’ estimate of the condition of the road network based on extrapolation of the pre-2005 data and informal visual surveys in 2009 established that only about 20% of the total network was still in good condition. Urban roads are among those that were hardest hit by the lack of funding for maintenance and therefore have experienced the worst levels of

Dodging the Potholes: The Spatio-Distribution and Socio-Economic Impacts of Potholes in the Residential Areas of Gweru, Zimbabwe

decline [1]. The main problem that has negatively affected the condition of Zimbabwe’s urban roads is the presence of potholes. These are however an increasingly common problem associated with roads worldwide. The presents of potholes and the general poor state of roads are a great source of irritation for most local councils and municipalities, as they do not have adequate resources to effectively fix them [4]. Potholes constitute a major concern with regards to road conditions because they develop quickly and are a serious hazard to the motoring public that ply local and transnational highways [5]. Vidal [6] argues that the poor condition of roads in Africa particularly the development of potholes is due to the extremes of sun and rain that bake the roads dry or leave them cratered and impassable. Pothole development is accelerated by the eating away of the bottom and sides of the pothole by rain water. As chunks of pavement peel off, the pothole grows larger and deeper and spreads quickly across the entire roadway if its growth is not timeously arrested [7]. On South African roads, pothole development has accelerated considerably due primarily to reduce preventative maintenance of many of these roads, combined with particularly wet periods during rainy seasons and rapidly increasing numbers of heavy vehicles [8]. Potholes can grow to meters in width, though they usually only become a few centimetres deep, at most. Roads strewn with potholes are a cause for concern to vehicle owners, drivers and the travelling public. They lead to high vehicle operating costs and lengthy travel times [2, 9-12]. VOCs (vehicle operating costs) include various direct costs to operate a vehicle such as maintenance, tires, fuel, labour, and capital costs. Roads in poor condition raise costs of operation because they reduce fuel efficiency, damage the vehicles leading to higher maintenance costs, reduce the life of tires, reduce vehicle utilization because of lower speeds, reduce the life of the truck

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and increase the risk of accidents [13, 14]. The bottom line is that motorists incur huge expenses whilst the travelling public experience great discomfort when travelling on roads strewn with potholes [15]. Potholes have become a topical issue in Zimbabwe as newspaper reports abound of motorists who have gone to the extent of suing some local councils for pothole induced damages to their vehicles. In 2010, a Zimbabwean banker won a court case against Harare City Council after her Mercedes Benz vehicle got damaged by a pothole along one of the major city roads [16]. On the other hand, a Bulawayo city high court judge had his car repaired by government after he threatened to sue the Bulawayo City Council for pothole damages to his car [17]. The problem of potholes in Zimbabwe has not been for Harare and Bulawayo alone as illustrated by court cases but for all towns and cities. Gweru City Council, for example, has faced challenges in constructing and maintaining its roads over the years. Several roads have had potholes for over a decade now. Meaningful road maintenance programmes in Gweru were carried out prior to the hyperinflationary period of 2000-2008. Since then the problem of potholes has remained a perennial issue and they are now a menace in the city’s roads. In recent years, Gweru city council has been patching potholes with soil therefore providing just a temporary respite as the soil is easily scooped away by vehicle wheels and rain water particularly in the summer season. There have been very few studies in Zimbabwe focusing on potholes and their impact on road users, vehicle owners, local authorities, vehicles themselves and the generality of the public. Based on the study of potholes in some selected suburbs in Zimbabwe’s third largest and centrally located city of Gweru, this paper seeks to fill part of this lacuna by analyzing the nature, distribution and the socio-economic impacts of potholes in the city of Gweru. 1.1 The Pothole Formation Process Potholes are partly caused by damage from weather

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related conditions. They occur when extreme shifts in weather patterns leave the ground unstable and prone to splitting. They are also caused by different weights from vehicles. Potholes may be accompanied by severe cracking and deformation or distortion of the surface around the pothole, indicating a deep-seated cause for pothole formation [18].

tarmac surface cracking which results in weakening of the road surface leading to pothole formation. There has been a 90% increase in the number of potholes on UK roads since the severe winter weather struck in 2009 [13]. The icy conditions have resulted in a huge surge in the number of potholes on Britain’s roads due to the freeze and thaw effect.

Where little deformation is observed in the vicinity

Tarred roads are particularly vulnerable to the

of the pothole, the cause is likely to be the entry of

erosive effects of water, causing the number of

water through superficial cracks in the road pavement

potholes forming each day to rise by 70% on South

and deterioration of only the surfacing and upper

African roads in heavy or continuous downpours [20].

structural layers of the pavement [19]. Overtime,

In February 2008 alone, about 5,200 potholes were

vehicles passing over the road force water deeper

reported to have formed in Johannesburg in the

through the soggy roadbed, eventually eroding parts of

summer season [20]. The development of potholes on

it. As the roadbed continues to erode, the asphalt begins

South African roads has

to sink into the eroded portions and eventually cracks

due primarily to reduced preventative maintenance

under the continued impact of vehicle tyres. This

being applied to many roads combined with

process is summarised in Fig. 1.

particularly wet periods during rainy seasons and

accelerated

considerably

rapidly increasing numbers of heavy vehicles [8]. 1.2 Other Causes of Potholes

Besides weather conditions, pothole formation on

Other causes of pothole formation are high traffic volumes, roadbed base failure, and drainage problems near or under the roadway, petroleum products such as diesel or gasoline spilling on the asphalt, frost boils, and utility failures [7]. In Europe, freeze-thaw action has been cited as one of the major contributors to

some Zimbabwean roads have been exacerbated by the

Rainwater sinks through cracks in old or weakened asphalt. The water is soaked up by the mixture of rock, gravel, and sand that supports the road.

Fig. 1

Vehicles passing over the road force water through the soggy roadbed and eventually erode parts of it.

The process of pothole formation. Source: Ref. [19].

end of the lifespan of many tarred roads. It has been observed that the city of Harare has a backlog of road maintenance dating back to 2002 showing great negligence on road maintenance by city councils of Zimbabwe [21]. Asphalt sinks into the eroded portions of the roadbed, cracks under the continued impact of vehicle tires leading to chunks of roadbed materials detachment.

Holes may be patched with proprietary cold patch or hot patch material.


2. Materials and Methods 2.1 Study Area The study was conducted in Gweru, the third largest city in Zimbabwe in terms of functions such as commerce, transport and industry [22] and the capital of the Midlands province. It is about 170 km from Bulawayo and 280 km from Harare along the Harare-Bulawayo road and railway line. Gweru was established in the late 1890s and became a municipality in 1917 [23]. This city is Zimbabwe’s main road and railway central junction with rail radiating to Harare, Bulawayo, Masvingo, Zvishavane, Shurugwi and the South-East Lowveld. The city has the country’s biggest marshalling yard at Dabuka. Gweru’s altitude is on average 1,430 meters above sea level [24]. Its climate is characterized by a dry season that extends from May to October and a wet season that stretches from November to April. The average annual rainfall is 670 mm. The average highest and lowest temperatures of Gweru are 27 °C and 16 °C, respectively [24]. Gweru is located along the rich mineral belt of the Great dyke and therefore both formal and informal particularly chrome and gold mining are major activities in its environs. The city is dominated by unstable silicate clay soils that shrink and crack during the dry season and compact during the wet summer season [25]. Gweru has a population of 146,073 people [26]. Its major industries include Zimbabwe Alloys, Bata Shoe Company, Cold Storage Commission, Zimglass and BOC Gases. According to the Zimbabwe Standard newspaper of October 10, 2010, some of the major companies like Radar Castings, Zimbabwe Casting, Kariba Battery Manufacturers, BOC Gases and Zimbabwe Alloys have shut down because of the land reform related economic meltdown of the 2000-2008 period. Gweru’s suburbs are divided into high, medium and low density residential areas. These divisions originated during the colonial era and were based on

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skin colour or racial lines until the achievement of black majority rule in 1980. Although suburban racial integration has significantly improved since then, the legacy of differential infrastructure and services provision still remains to this day. Among the high density suburbs are Mkoba, Mtapa, Senga, Nehosho, Mambo and Ascot, most of which are located to the west of the city, close to heavy industries and were designed for the indigenous black residents. Infrastructure and service provision in these suburbs was and remains the most inferior. It also deteriorates rapidly due to its inherent poor quality and overutilization. The medium density suburbs that are also moderately provided for infrastructure and services wise include Nashville, Lundi Park, and Northlea which were originally designed for members of the coloured community. The low density residential suburbs of Harben Park, Ridgemont, Kopje and Windsor Park among others were designed for the population of European origin or decent and therefore have the most superior infrastructure and services. The locations of the sampled residential areas in the city of Gweru are shown in Fig. 2. 2.2 Data Collection Methods Nine semi-structured interviews were held with different commuter owners, private car operators, mechanics and the Gweru city council roads engineer soliciting for information on socio-economic problems associated with the many pothole-strewn roads in the city. The interviews were held on different days to cater for the varied work schedules of the targeted interviewees. The six commuter omnibus owners interviewed were conveniently selected and they represented all residential areas sampled for study. They were chosen on the basis of their knowledge of repairing costs they encounter as they operate the public transport vehicles business. Two mechanics were purposively sampled and interviewed about nature of vehicle damage caused by potholes and their costs to commuter operators.

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Fig. 2 Location of the city of Gweru (study area).

The Gweru city roads engineer was also interviewed to get information about the management and financing of road construction and maintenance in the city of Gweru. The interview method was advantageous in that it provided in-depth information about types of vehicle defects, related costs and road construction and maintenance issues. Questionnaires were self-administered to passengers and commuter omnibus drivers. Forty volunteering respondents who were present during the time of the survey at the city commuter omnibus ranks were randomly selected and requested to fill-in the questionnaires at the ratio of 30 questionnaires for commuter drivers and 10 questionnaires for passengers. The drivers were judged to have useful information on pothole problems owing to the nature of their work Table 1

whilst the passengers provided an overview of the socio-economic impacts of potholes to the commuting public. Field measurements were conducted to determine the specific position, nature and dimensions of the potholes on studied roads in different residential suburbs. The sampled streets are shown in Table 1. The exact location of the potholes on the roads was determined using a hand-held GPS (global positioning system) receiver where the X:Y coordinates were recorded on a mapping data sheet. Observations were done on sampled streets focusing on the state of the roads using a ranking of 1-5 (adopted from the Indian roads coding system) and pothole characteristics such as shape, size and position. A digital camera was also used as an observation tool and

Sampled streets in the different residential areas of Gweru.

Residential area Senga-Nehosho Kopje Ridgemont Mkoba 6 and 7 Lundi Park Ivene

Sampled streets Ziyambi Drive, Matongo Way, J Shava Road, Chiwaya Street and Senga Road Kopje Road, Strand Road, Princes Drive, George Avenue Hillcrest Road, Umsungwe Road, Grays Road Mkoba Road, Paradza Road, Chilimanzi Road, Hamutyineyi Road, Makoni Street Lundi Road, Malvern Avenue, St Annes Drive, Coughlan Avenue Murifield Avenue, Rosemere Street, Gulane Road, Turnberry, Rivermead Road


some images were taken to give a vivid illustration of the state of the roads.

3. Results and Discussion 3.1 Senga and Nehosho High Density Residential Areas A total of 47 potholes were analysed on sampled roads in Senga and Nehosho residential areas. A stretch of about 11 m × 6 m at the intersection of Ziyambi Drive and Matongo Way and a 20 m × 6 m stretch along Ziyambi Drive are now more of gravel than paved surfaces. 36% of the studied potholes were small (less than 150 cm in circumference), 34% were medium sized (151-300 cm in circumference) whilst 30% were large (more than 300 cm). Large potholes at some points such as at the intersection of Chiwaya Street and Senga Road have circumferences averaging 568 cm, diameter of 242 cm and 6.2 cm in depth covering almost the whole lane. The distribution of potholes recorded and measured on sampled streets in Senga and Nehosho high density areas is shown in Fig. 3.

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Interviews held with some of the Senga-Nehosho commuter omnibus owners and the city engineer revealed that the city council once carried out pothole patching but the potholes resurfaced after a very short period of time. This was mainly because the city council lacks financial resources and therefore uses pit sand, the cheapest material available for patching up potholes. At the intersection of Ziyambi Drive and Matongo Way the road has become an almost completely gravel section with patches of tar remaining only on recently patched parts as shown in Fig. 4. Ziyambi Drive is the main road used by both public vehicle transporters and private cars getting into Senga and Nehosho suburbs. The high traffic volumes and the impact of turning vehicles at the intersection of Ziyambi Drive and Matongo Way have exacerbated pothole development particularly at the intersection. Poor drainage resulting in waterlogging, high traffic volumes, lack of timeous maintenance and poor construction standards have been cited as the main drivers of the high rate of pothole development in the Senga-Nehosho area.

Fig. 3 Distribution of potholes on sampled streets in Senga-Nehosho residential area.

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Fig. 4 State of the road at Ziyambi Drive and Matongo Way intersection in Senka-Nehosho area.

Ziyambi Drive is the most highly potholed road compared to other streets in the two suburbs as evidenced by the high pothole concentration per unit distance. Some potholes have merged along this road to form about 20 meters of continuous gravel stretches. Drivers and passengers also concurred that Ziyambi Drive leading to Nehosho and Senga road leading to Midlands State University have most potholes. This was because these are the major roads used by public transport into the suburbs. Damage is even worse at the corners and intersections of these busy roads. This was corroborated by direct observation. Senga road leading to Midlands State University however has the advantage of receiving frequent and thorough attention from the city council at the insistence of the university authorities who ply the road almost on a daily basis. This road is therefore generally in a moderate state when compared to Ziyambi Drive and others of similar utilization intensity. Matongo Way and Chiwaya Streets both also have fewer potholes because fewer commuter omnibuses and small vehicles ply these roads. 3.2 Mkoba 6 and 7 High Density Residential Area There were about 17 potholes recorded on sampled roads in Mkoba 6/7. Patching work using pit sand had just been done on several roads at the time of study but Paradza Road linking Mkoba Road and Chilimanzi Road had not been patched despite clear evidence that the city council was through with maintenance work in

the area. This was because the city council targeted major roads only. At the intersection of Chilimanzi and Hamutyinei Roads the formerly tarred surface is now just a gravel surface. Observations showed that the main cause of damage along these two roads were the construction trucks heavily loaded with sand, bricks and concrete to the recently established residential area where the housing construction business is booming. The Gweru city council roads engineer revealed that Hamutyinei Road was resealed in 2009, but with the high traffic volumes found along the route, potholes of various sizes are already a common feature and the demand for frequent maintenance is beyond the current capacity of the local authority. The city engineer felt that with the current challenges bedevilling the city council, Hamutyinei Road was in a good state despite the existence of occasional potholes. The main affected area in Mkoba 6 and 7 was the intersection of Paradza and Chilimanzi Roads where five potholes with circumferences above 301 cm were identified. These were mainly due to poor or lack of maintenance work done on Paradza Road. Fig. 5 shows the distribution of sampled potholes in villages 6 and 7 of Mkoba high density residential area. 3.3 Ridgemont Low Density Residential Area Ridgemont, like other low density suburbs formerly meant for residents of European origin or decent, has generally moderate to low potholed roads. The main affected roads are Grays and Hillcrest. Hillcrest Road


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Fig. 5 Distribution of potholes on sampled streets in Mkoba 6 and 7.

has since been abandoned as it resembles a gravel road. There has been extensive soil filling on the road. Grays Road has eight potholes which are generally spaced. The biggest pothole recorded along this road measured about 510 cm in circumference, 236 cm in diameter and had a shallow depth of about 0.8 cm. Shallow depths indicate that Grays Road has a strong and thick surface and the tar surface is only giving in due to age, stress caused by tyre pressure and climatic variations. Although potholes in this area are few, majority of them are large (60%) whilst 40% are medium size. This implies that there has been little work done on maintenance recently as there is no much formation of new potholes but continued freaking of the already existing ones. The few potholes found on Grays Road can be attributed to the aging of the roads and little or no maintenance services by the city council. Ridgemont suburb roads are not frequently maintained because among other reasons. The suburb’s residents are less influential politically as well as in council matters. Fig. 6 shows potholes on sampled roads in Ridgemont low density suburb.

3.4 Kopje Low Density Residential Suburb This suburb has roads with the least amount of damage compared to all the other sampled residential areas. Among the four sampled roads only Strand Street had two large potholes with diameters of 212 cm and 186 cm, depths of 3.56 and 2.8 cm and circumferences of 528 cm and 394 cm, respectively. These potholes are a result of road weakening due to overgrown road side tree-roots prying laterally below the surface leading to the development of road surface cracks. The cracks promote water infiltration and are therefore both widened and deepened by vehicle movement forming the potholes that were observed. Kopje Road, George Avenue and Princess Street are in perfect condition despite their advanced ages. These roads have been resistant to weakening caused by water infiltration because they were constructed at a gradient that facilitate good drainage. In addition, the low density suburbs such as Kopje are homes to some of the most influential individuals in the city such as high ranking city fathers, political heavy weights and top business people. This results in streets in these

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Fig. 6 Potholes on sampled streets in Ridgemont residential area.

Fig. 7 Potholes on sampled streets in Kopje residential area.

suburbs receiving urgent attention whenever their conditions deteriorate. Some points where signs of surface freaking due to aging were evident were however recorded but they were not well developed to be a cause for concern. However, this is the stage at which maintenance should be done to neap the problem whilst it is still in the buck and keep both maintenance and vehicle damage low. Fig. 7 shows pothole

positions in Kopje low density suburb. 3.5 Lundi Park Medium Density Residential Area Lundi Park, a medium density residential area, had clear signs of negligence as far as road maintenance is concerned. The potholes in this residential area range from 66 cm to 337 cm in circumference, 25.3 cm to 168 cm in diameter and depths between 0.96 cm and 3.6 cm.


Most potholes are on Malvern Street where eight potholes were recorded and 83% of these were on the centre of the road with an average depth of 1.83 cm. 67% of the potholes were small, 17% were medium and 16% large in size. The big proportion of the small potholes shows that there are higher rates of pothole formation associated with the rain season. The low gradient of the roads promotes the accumulation of water thereby weakening road surfaces that causes potholing of several sections. This is worsened by little or lack of timeous maintenance work to arrest further road deterioration in the residential areas. Fifteen potholes were recorded on the sampled streets in Lundi Park suburb as shown in Fig. 8. 3.6 Ivene Medium Density Residential Area Of all the potholes that were recorded on sampled roads in Ivene residential area, 47% were large, 33% were medium and 20% were small. The largest pothole which resembles a wilderness ditch along Murifield Road has a circumference of 598 cm, depth of 8.7 cm and a diameter of 305 cm. This poor condition of roads in Ivene is a result of a combination of factors chief

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among them being aging, substandard construction, gentle gradient promoting water infiltration, weak unconsolidated sand soils that dominate the area and lack of maintenance. A stretch on Murifield Road leading to Ivene shops shown in Fig. 9 bears testimony to what commuter omnibus drivers and the suburb residents called “the suburb of the bumpy roads”. There is no doubt that by any standards, roads in this area are in a very dilapidated state with little patches of tarmac remaining behind predominantly gravel surfaces. Most commuter omnibus owners whose vehicles ply these routes complained of serious mechanical damage to vehicles warranting high frequency of repair services and raising the costs of the transport business in the area. In addition to the causes of poor road conditions in the area already stated, the roads in the area particularly Murified Road are frequented by heavy vehicles carrying construction sand further accelerating the rate of deterioration of the roads in the area. In the inner areas of the suburb, commuter omnibuses are the main vehicle traffic. These have also caused their own fare share of damage along Turnberry, Rosemere and Gulane roads as evidenced by the presence of some long elongated

Fig. 8 Potholes on sampled streets in Lundi Park residential area.

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Fig. 9 Aged and neglected Murifield road strip in Ivene residential area.

Fig. 10 Potholes on the sampled streets in Ivene residential area.

potholes along these inner suburb roads. The recorded potholes are shown on the street map of Ivene in Fig. 10.

4. Rate of Pothole Existence on Sampled Roads There are higher rates of pothole formation in the high density residential areas as compared to low density residential areas. In fact, the potholes follow

the population density trend in the residential areas of Gweru. High density residential areas have the highest rates of pothole formation per unit distance, followed by medium density suburbs and lastly low density suburbs of Kopje and Ridgemont as shown in Fig. 11. This tallies with the city roads engineer’s survey results in which she highlighted that the roads in high density residential areas are more prone to pothole development due to the low cost surfacing applied as


tar surfacing is expensive. The Gweru City Council Roads engineer cited the economic meltdown that Zimbabwe experienced between 2000 and 2009 as the main contributing factor towards lack of an effective road maintenance programme during this period since this chronically incapacitated the local authority to carryout maintenance work on the already poor road network particularly in high density residential areas. Traffic volumes in high density roads have substantially increased due to the introduction of the 12 to 35 seater commuter omnibuses since the 1990s as compared to the 65 to 75 seater Zimbabwe United Passenger Company (ZUPCO) big buses. The big buses had their fare share of challenges with regards to residential areas’ road conditions due to their size, significantly damaged particularly weakly constructed high density suburban roads. The high commuter omnibus traffic volumes have further weakened the substandardly constructed and aged tar surface causing potholes development. The potholes are further enlarged during wet periods since they are collection points for rain water leading to the peeling off of asphalt due to tyre pressure. However, maintenance work was resumed on some roads after the adoption by the government of the multi-currency system in 2009. The liquidity crises

Fig. 11

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combined with political bickering between the former opposition MDC party-led Gweru City Council and the ZANU PF-led Ministry of Local Government and Urban Development has seen service delivery including road maintenance progressing at a snail’s pace and mostly employing ineffective methods and materials such as pothole patching with gravel which is easily washed away by running water. The areas that have benefitted from these temporary measures include Senga mainly the City-Senga-MSU road, some areas in Mkoba as well as areas around the city centre. The medium density residential areas of Ivene and Lundi Park are yet to have their dilapidated road surfaces attended to. Standard surfacing done in low density residential areas such as Kopje during the colonial period is still intact. The roads in low density residential areas were properly constructed during the colonial era to ensure that the residents enjoy quality urban life such as roads among other services. The pothole formation rates per kilometre in the sampled suburbs are shown in Fig. 11.

5. Socio-Economic Impacts of Potholes From the interview carried out with the Gweru City Council Roads engineer, potholes remain a perennial problem as road construction and/or maintenance is

Number of potholes found on sampled roads per kilometre in residential area.

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very costly and worse still the council lacks its own road maintenance equipment and plant. Hiring of road maintenance equipment is costly and therefore pothole repair at most times is not done up to standard. There is need for proper compaction using the right type of materials for the potholes to be completely sealed but the Council lacks both appropriate equipment and road surfacing materials leading to manual compaction using hand-held tools and soil which is ineffective and short lived. About 70% of the money allocated to the road construction and maintenance budget is spent on hiring equipment and thus very little money is left to cover all areas of need. To solve the problem, the city council resorts to pothole patching, resealing, and overlaying. Commuter minibus drivers, like other motorists and the travelling public, seriously complained about the challenges faced when driving on potholed roads. One can hardly drive without occasionally swerving to avoid the potholes. “I have to meander to find my way in a pothole-damaged road to minimise the huge expenses incurred after hitting potholes”, one driver stated. In many instances, an entire lane could be full of these potholes which are almost unavoidable at night and when it is raining. Some of the impacts of potholes on the commuter minibus owners operating in the studied areas are summarised in Table 2. Potholes affect vehicle operating costs particularly the costs associated with maintenance, tyres and fuel.

Roads in poor condition result in higher variable costs of operation because they reduce fuel efficiency, damage vehicles leading to higher maintenance and higher operation costs, reduce the life of tyres, reduce vehicle utilisation due to lower speeds and reduce the life of the truck [14]. In the studied areas, commuter minibus operators experienced all the variable costs, that is, high fuel consumption, frequent maintenance, tyre damage notably frequent punctures, reduced business due to low speeds and complete vehicle breakdown beyond repair over short operating life span particularly operators plying high density residential area routes such as in Senga-Nehosho and Mkoba. Vehicle mechanics concurred that most cars develop suspension defects since most vehicles are not designed to deal with the sharp and repeated shocks caused by potholes. One of the mechanics interviewed stated that pothole-related vehicle damages are rampant especially in the wet season as most potholes form during this time and drivers hit them unaware as they will be concealed under flood waters. Furthermore, pothole induced vehicle mechanical faults and the general poor state of roads increase the risks of accidents and loss of life costing individuals, families, companies and the government valuable financial, human and other material resources for the much needed development activities. With respect to suspension problems, interviewed vehicle mechanics stated that they can not be fixed in any other way besides through replacement which requires more

Table 2 Mechanical and economic impacts of potholes to commuter owners by route operated. Area

Spare parts replacement

Suspension, ball Senga-Nehosho joints, tyre once in every 4 months

Repairs

Tickets/fines

Bent rims, tyre punctures

At least 5 a month/vehicle, may receive more during public holidays

Mkoba 6/7

Tyres, ball joints, Tyre puncture, suspension bent rims

At least 3 a month/vehicle

Ridgemont

Tyre punctures

At least 1 a month/vehicle

Ivene/Lundi Park Tyres, ball joints

Tyre punctures

Vehicle impoundments

Other impacts High fuel consumption rates, engines not fuel efficient

2 vehicles for three weeks-not road worth

1, no recent safety review document

High fuel consumption, expensive servicing monthly Car parts mostly imported becoming costly to service the vehicles


money and labour than other technical problems. Some commuter minibus drivers and vehicle owners pointed out strategies they have adopted to minimise the huge expenses incurred after hitting potholes. Preventive maintenance is delayed or in some cases skipped altogether. For those operating older vehicle models with simpler technology, the vehicle owners and/or drivers tinker with their engines and improvise repairs and parts to lower maintenance costs and challenges of replacement parts shortage and unavailability. This entails servicing or repairing the vehicle at the backyard or on the road side instead of taking them to garages with trained mechanics. Most commuter minibus crews indicated that trouble shooting skills are paramount and every member has to have them since the vehicle can just “cease” on the middle of the road after hitting a pothole. This necessitates along the road repair work to enable business to continue. It is only the problems they would have failed to address that are referred to specialists. With regards to tyres, the tendency is to resort to cheaper low quality second hand tyres and retreaded ones. To reduce fuel consumption, some drivers stated that they engage the neutral gear and switch off the engine on steep sections of the road, allowing the gained momentum and gradient to drive the vehicle for the entire extent of the steep reach. Potholes have also been reported to cause ball joint, rims and tyre damage as well as mis-alignment of wheels and engine malfunctioning. Most commuter omnibus drivers complained that the problem of wheel alignment and suspension problems compromise their driving as it affects steering control. Furthermore, when the drivers dodge the potholes, the police accuse them of careless driving and fine them on the spot. The penalties are paid for by the vehicle owners straining the employer-employee relations. During the hyper-inflationary and economic collapse period of 2000-2009 some vehicle owners operating in high and medium density suburbs such as Ivene/Lundi, Mkoba and Senga ceased operations as

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vehicle repair parts such as ball joints, tyres and rims were both unaffordable and unavailable on the local market. Unroad-worthy vehicles impounding by the VID (Vehicle Inspection Department) has also compounded vehicle owners’ problems as they have to pay a fine or a bribe and thereafter incur repair costs. Though Commuter Owners Association representatives hold periodic meetings with the Gweru City Council authorities pertaining to road conditions among other issues, there have been slight improvements as potholes continue to resurface and mostly in the same areas and positions. Some commuters however applauded the effect of potholes on speed since commuter omnibus drivers have a tendency of speeding even in residential areas risking running over children that always use roads as playgrounds. Passengers experience their own share of problems caused by bumpy potholed roads. They complain of unexpected “earthquake” bumps when they are onboard the commuter vehicles and private cars. Others have had the devastating effects of getting maimed and losing their loved ones in accidents caused by the bad state of the roads in which drivers encroach into another lane to avoid potholes. The pothole problem therefore needs real attention if development and socio-economic benefits are to be drawn by all sectors of society.

6. Conclusion and Recommendations Problems of funding from the central government have led to poor infrastructure development and maintenance especially in some high density residential areas such as Senga-Nehosho and Mkoba 6/7. The roads in Senga-Nehosho, Mkoba and Ivene are in a bad state causing real threats to road users’ safety as some have become worse than rural unmaintained gravel roads. A combination of low cost surfacing, poor drainage and high public transport vehicle volumes make high density areas’ road network more prone to pothole formation than low density areas. The

888


pothole frequency per unit distance increases from low density suburbs to high density areas and therefore high density areas have roads in poorest condition compared to medium and low density areas. The way in which road maintenance is being carried out by the city authorities lives a lot to be desired. The measures being taken to address road infrastructure challenges are piecemeal, limited in scope and very temporary in character making the efforts costly to the local authority itself, transport operators and the commuting public. Mostly, repairs are substandardly done during the rain season exposing the seal to strain and lasting only a few weeks if the rains are strong. The city council must note that patching is no longer the solution, most roads especially in the high density areas need complete rehabilitation since they were allowed to deteriorate for too long. There appears also to be selective maintenance of the roads with those in low density areas receiving more attention than those in high density areas making the pothole problem more of a low class perennial problem as compared to the upper class who reside in low density residential areas. Given the prevalence of potholes on Gweru roads particularly in high density areas, there is need for council to put notices on roads signalling drivers to slow down in pothole areas. Some heavily depleted roads like Murifield Road in Ivene and some parts of Ziyambi Drive in Senga-Nehosho have gone past their

daily to and from work. Council should also work with telecommunication companies and establish toll free lines for road users to report potholes directly to the council as and when they form. This will ensure timeous attention to the potholes and reduce continuous tarmac surface depletion. There should be equal surfacing for all residential areas and even better surfacing in high density areas as there are higher traffic volumes warranting frequent and stronger surfacing. There is also need for the local authority

mostly use small commuter omnibuses which ply the

roads/streets as part of their cooperate responsibility so as to assist in road infrastructure development and maintenance.

recruitment

of

road

may be helpful in reducing pothole development. Council must diversify its revenue base by embarking on fund raising projects so as to buy road maintenance equipment which it desperately needs for both road development and maintenance.

References [1]

[2]

[3] [4]

[5]

workers should timely report any potholes forming in their places of residence as they can monitor the roads

Seasonal

maintenance workers especially during the wet season

on the roads should therefore be prioritised by the city surveys of roads to determine their state. City Council

private

and industrialists are encouraged to adopt specific

roads continuously on a daily basis. Safety of citizens council. The City Council should make continuous

with

insurmountable challenge. Local business operators

necessary given the fact that more than 70% of the city’s population reside in high density suburbs and

partnerships

other services since going it alone has proved to be an

density residential areas should be continually accommodate high traffic volumes. This is especially

foster

organisations in road maintenance and the provision of

lifespan and need complete resurfacing. Roads in high monitored against pothole development as they

to

[6]

AFDB, Road transport services and infrastructure, African Development Bank Zimbabwe Report [Online], 2011, pp. 1-44, www.afdb.org/.../11.%20Zimbabwe%20ReportChapter% 209.pdf (accessed Feb. 12, 2012). I.G. Heggie, Management and financing of roads: An agenda for reform, World Bank technical paper No. 275, Africa Technical Series, Washington DC, 1995. Review of Selected Railway Concessions in Sub-Saharan Africa, World Bank, Washington DC, 2006. R. Ahimbazwe, A.M. Kakebe, Kampala City Roads Condition [Online], 2010, http://www.wisegeek.com/what-is-apothole.htm (accessed Dec. 14, 2011). S.E. Smith, What is a pothole? [Online], 2003, http://www.wisegeek.com/what is-a pothole.htm (accessed Mar. 20, 2011). J. Vidal, Climate change will cost poor countries billions


[7]

[8] [9]

[10]

[11]

[12]

[13]

[14]

of dollars [Online], 2011, http://www.guardian.co.uk/global-development/povertymatters/2011/jun/15/climate-change-cost-poor-countriesbillions (accessed Feb. 12, 2012). S. Feighan, Maintenance of transport network vital for growth, Fontana Herald News [Online], 2009, http://www.fontanaheraldnews.com/articles/2012/02/02/n ews/doc4f24c3470eaaa171757314.txt (accessed Dec. 14, 2011). A. Dlamini, Pothole Puncture, World Cup Legacy, I Net Bridge, 2010. J.L. Hine, S.D. Ellis, Agricultural marketing and access to transport services, in: Rural Transport Knowledge Base, Rural Travel and Transport Program, World Bank, Washington DC, 2001. S. Brushett, Experience in reforms of road maintenance financing and management in sub-Saharan Africa, Transport and Communication Bulletin for Asia and the Pacific, New Delhi, No. 75, 2005. P. Buys, U. Deichmann, D. Wheeler, Road Network Upgrading and Overland Trade Expansion in Sub-Sahara Africa, Technical report for Development Research Group, World Bank, Washington DC, 2006. A. Storeygard, Farther on down the road: Transport costs, trade and urban growth in sub-Saharan Africa, Preliminary Paper Draft, 2011. (inpublished) M. Godfrey, Britain suffers a pothole problem after the snow [Online], 2010, http://trifter.com/europe/united-kingdom/britain-suffers-a -pothole-problem-after-the-snow/ (accessed Dec. 14, 2011). S. Teravaninthorn, G. Raballand, Transport Prices and

[15]

[16] [17] [18]

[19]

[20]

[21] [22]

[23]

[24]

[25] [26]

889

Costs in Africa: A Review of the Main International Corridors, AICD Working Paper 14, Technical report for the International Bank for reconstruction and development, The World Bank, Washington DC, 2008. C. Musarurwa, P. Runyowa, ‘War-torn’ country roads in sunshine city, in: The Sunday Mail, Government Printers, Harare, 2012. The Herald, Government Printers, Harare, June 8, 2010. The Standard, Government Printers, Harare, July 18, 2009. J.O. Fadare, Multi-sectoral approach to urban growth management in Africa, Journal of the Nigerian Institute of Town Planners 1 (2008) 33-52. P. Green, A. Maharaj, J. Komba, Potholes: Technical Guide to the Causes, Identification and Repair, CSIR Publications, South Africa, 2010. E. Visser, Johanesburg Targets Potholes [Online], 2008, http://www.joburg.org.za/content/view/486/80 (accessed Dec. 14, 2011). The Herald, Government Printers, Harare, 2011. T. Brinkoff, City Population [Online], 2007, www.citypopulation.de.Zimbabwe.html (accessed Mar. 12, 2011). M.B. Munochiveyi, An economic history of industrialization in Zimbabwe: The case of Gweru town, UZ, 2001. (unpublished) S. Styleshout, J. Summerweb, Climate Data [Online], 2011, www.climatedata.env.climate (accessed Dec. 14, 2011). N. Nyamapfene, Soils of Zimbabwe, Longman, Harare, 1991. Midlands Census Report, Government Printers, CSO, Harare, Zimbabwe, 2002.


D

DAVID

PUBLISHING

The Relationship between Meteorological Variables and Clearness Index for Four Urban/Suburban Areas of Brazilian Cities Francisco José Duarte Gomes1, Luciana Sanches2, Marcelo de Carvalho Alves3, Marta Cristina de Jesus Albuquerque Nogueira4 and José de Souza Nogueira1 1. Department of Physics, Federal University of Mato Grosso, Cuiabá 78060-900, Brazil 2. Department of Sanitary and Environmental Engineering, Federal University of Mato Grosso, Cuiabá 78060-900, Brazil 3. Department of Soil and Rural Engineering, Federal University of Mato Grosso, Cuiabá 78060-900, Brazil 4. Department of Architecture, Federal University of Mato Grosso, Cuiabá 78060-900, Brazil Received: November 1, 2011 / Accepted: April 18, 2012 / Published: July 20, 2012. Abstract: This study aimed to examine the relationship between meteorological variables and the clearness index for three sites in Cuiabá city and one site in Chapada dos Guimarães city, Brazil during 2007. It described the microclimate of each site on the basis of constructive elements and their surroundings, considering sky coverage using a daily clearness index. The results were that micrometeorological values were influenced by the natural elements and construction within the surrounding site, with higher air temperatures in more urbanized areas and sites with high diffuse radiation. When determining the sky coverage, on average, the days were partly cloudy or cloudy due to two reasons: (a) during the wet season, rainfall created cloudy conditions and (b) during the dry season, increases of particulates in the atmosphere as a result of anthropogenic emissions of gases and aerosols in this region of the state resulted in sky conditions classified as partly cloudy and cloudy. Future research should aim to better quantify the measurements taken inside an urban area, considering the topography and vegetation cover. This will improve the models that support urban planning, therefore favoring the thermal comfort of areas already occupied or to be urbanized. Key words: Tropical climate, urban climate, cover sky, microclimate.

1. Introduction Deforestation in Brazilian Amazonia is concentrated on an “arc of deforestation”, a crescent-shaped band along the eastern and southern edges of the forest, including the state of Mato Grosso. Compared with forests in the remainder of Amazonia, those in the arc of deforestation have lower biomass (and smaller diameter trees), and a drier climate. These characteristics facilitate fires with high burning efficiency when the forests are cleared in preparation for agriculture and ranching [1]. Cuiabá is the capital Corresponding author: Luciana Sanches, Ph.D., main research field: atmosphere-biosphere interaction. E-mail: [email protected].

city of Mato Grosso state, geographically located in the central south of Brazil and surrounded by three natural ecosystems: Savanna, Wetland (Pantanal) and Amazon forest. The climate of Cuiabá has been affected by deforestation of the Amazon and the practice of burning in the north of Mato Grosso state. As well as in other affected regions of Brazil, fires can occur throughout the year. However, regardless of their origin, fires tend to be more intense between August and the beginning October [2]. Cities create their own microclimates, mainly by modifying the energy exchanges with the atmosphere above [3] generally influenced by the energy of the sun and infrared radiative losses governed by the air and

The Relationship between Meteorological Variables and Clearness Index for Four Urban/Suburban Areas of Brazilian Cities

surface temperature. The microclimate of an environment in the tropics (regions characterized by low latitude and excessive solar radiation) is determined by the thermodynamic balance between absorbed solar energy and dissipated energy. This is based on four mechanisms: the emission of long wave radiation (from the surrounding surfaces), the material’s heat conduction, the water evaporation, and the heat convection from surfaces to the air [4]. The amount of global solar radiation and its temporal distribution are the primary variables used in the design of solar energy systems. Knowledge of these parameters is required for the prediction of the performance of a possible solar energy system at a particular location [5]. However, this balance is mostly due to the effect of changes in cloudiness on a number of environmental variables. For example, solar radiation across the atmosphere suffers attenuation by the phenomena of reflection, absorption and diffusion. Such processes occur when light rays interact with the gas constituents of the atmosphere, with clouds and/or particulate matter briefly in the atmosphere [6]. On cloudy days, for example, global solar radiation received by an ecosystem decreases, while the diffuse radiation received by an ecosystem increases [7]. Climate change caused by increased anthropogenic emissions of carbon dioxide and other greenhouse gases is a long-term climate hazard with the potential to alter the intensity, temporal pattern, and spatial extent of the urban climate in metropolitan regions. Clearness index, KT, provides a measure of the atmospheric effects at the place of solar insolation, providing an indication of the degree of cloudiness and atmospheric conditions for a given region [8]. However, the clearness index is a stochastic parameter, which is a function of the time of year, season, climatic condition and geographic location. Therefore, to include the atmospheric effects on the solar insolation at a given place, a model for the clearness

891

index is essential. To develop a model for the clearness index, the solar insolation on a horizontal surface for a few locations is measured over a period of time, encompassing all seasons and climatic conditions [9]. In the literature, several studies have presented findings on estimating clearness index and solar radiation values based on statistical approaches, artificial neural network techniques, and wavelet analysis. Several methods have been employed to study the urban climate such as comparison of urban and rural meteorological stations, analysis of climatic factor time series of stations that have been included in the urban area due to city growth and the method of transects around the city [10]. The aim of this study was to investigate the relationship between meteorological variables and clearness index (KT), so as to reveal the effect of change in cloudiness on microclimate, for four selected sites with different urban designs in Cuiabá city and Chapada dos Guimarães city, Brazil.

2. Material and Methods 2.1 Sites Descriptions Field observations were performed at three sites in Cuiabá city (15º35′56′′S; 56º06′01′′W, at an altitude of 165 m) and one site in Chapada dos Guimarães city (15º27′38′′S and 55º44′59′′W at an altitude of 811 m), which is approximately 62 km from Cuiabá city. The study region is located in the central west of Brazil. The city of Cuiabá has an area of 3,538.17 km2, and the urban area occupies 254.57 km2. The Cuiaba climate, according to the Köppen classification is Aw and tropical hot and semi-humid with two seasons. These seasons are defined by the distribution of rainfall: the rainy season (spring-summer) and dry season (autumn-winter). The annual rainfall varies from 1,200 mm to 1,500 mm and the mean annual relative humidity is 74% according to data from INMET (Instituto Nacional of Meteorologia) from 1961 to 1990.

892


The Chapada climate, according to the Köppen classification is Aw, with an annual average air temperature that is 24 °C [11]. However, the monthly minimum can drop to 0 °C (at night) during June to August. The annual rainfall can reach 2,000 mm, with most rain from December to February. Two seasons were defined for the region: a rainy season (October to March) and a dry season (April to September). The seasonal climate of the study area was defined, based on the average monthly rainfall in a 70-year period, obtained 40 km southwest from the study area. The urban area is located in a depression surrounded by a plateau, causing the frequency and average wind speed to be extremely low, with an average annual rate of 1.7 m/s. This minimizes the effect of thermal exchanges by convection. Air temperature is further influenced by the built space [12]. The study was conducted using climate data from weather stations at three points in the city of Cuiabá and one point located in Chapada dos Guimarães city during January and December 2007 (Table 1). Fig. 1 shows the locations and illustrates the surroundings of the studied sites. 2.2 Instrumentation

2.3 Estimation of the Clearness Index and Cover Sky It used a clearness index (KT) to describe changes in cloudiness. Sky coverage was determined by the clearness index (KT) (Eq. (1)), defined as the ratio of the incident solar radiation (Rsg) (MJ·m-2·day-1) and irradiation in the upper atmosphere (Ro) (MJ·m-2·day-1). KT 

Rsg Ro

(1) The classification of the sky coverage was based on Ref. [13]. A cloudy sky was defined in the range 0 < KT < 0.3, a partly cloudy sky between 0.3 ≤ KT ≤ 0.65and a clear sky between 0.65 < KT < 1.0. Irradiation in the upper atmosphere (Ro) (MJ·m-2·day-1) was calculated by Eq. (2):    Ro  1367 Eo Ws sen .sen  cos  . cos  .senWs  (2)  180

The air T (temperature), RH (relative humidity), Ppt (precipitation) and Rsg (global solar radiation) were measured by sensors installed in meteorology stations (WM 918 and Datalog with Vantage Pro2 console Manufacturer, Davis Instruments), programmed to store data every 30 minutes during the year 2007. To protect the weather stations, at the Center site, it was installed at a height of 4.20 m above the ground, at the CPA site at 10.50 m, at the Unicamp site at 7.60 Table 1

m and at the Chapada site at 7.40 m. Two seasons were defined for the region: a rainy season (October to March) and a dry season (April to September). This definition was given for each season, in accord with the average annual rainfall of Climatological Normals from 1931 to 1960 and from 1961 to 1990.



where, Eo is the correction factor of eccentricity of the orbit (Eq. (3)), Ws is the solar angle (degrees) (Eq. (4)), f is the local latitude (degrees) and d is the solar declination (degrees) (Eq. (6)).

Eo  1.000110 0.034221cos  0 . 00128 sen   0 . 000719 cos 2  where, Φ is defined by Eq. (4) according to the Julian day (dJ). 

2 dJ  1 365.242

(3)

(4)

Description and location of the four studied sites.

City

Cuiabá

Chapada dos Guimarães

Local name

Coordinates

Altitude

Center

15°36′1′′S; 56°5′29′′W

187 m

CPA

15°33′59′′S; 56°4′30′′W

239 m

Unicampo

15º45′45′′S; 56º3′57′′W

202 m

Chapada dos Guimarães

15°27′32′′S; 55°45′15′′W

809 m

Description Dense population and heavy traffic, concrete buildings and pavements Area with average building density and near of lake Sub rural area Urban area of low density and climate typical of mountainous regions

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Fig. 1 Site localization where the meteorological stations were installed on LANDSAT 7 ETM+ Image (GeoCover 2000). Density of buildings for Center (#1), CPA (#2), Unicampo (#3) and Chapada (#4) sites on QuickBird images.

Ws  ar costg .tg   360 284  dJ  365  

  23.45sen 

(5) (6)

3. Results and Discussion

January-March and October-December. Incoming global solar radiation (Rsg) received by the sites was higher during the wet season for the four sites (Fig. 2). The Center, Unicampo and Chapada sites had similar seasonality. At the Chapada site, the

3.1 Seasonal Trends in Micrometeorological Variables

solar

Fig. 2 shows the seasonal variations in meteorological variables of the four sites from January to December 2007. The annual accumulated precipitation varied from 1,024 mm to 1,322 mm for the four places with higher indices during

demonstrated higher cloudiness. The air temperature patterns of the four locations selected for this study can be clearly seen. As expected, for both sites studied, air temperature presented a consistent seasonal variability, varying

radiation

was

less

because

this

region

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Fig. 2 Monthly average of air temperature (°C), relative humidity (%) and incoming solar radiation (W·m-2) for Center, CPA, Unicampo and Chapada sites from January to December 2007.

over the months, with a lower monthly temperature during the dry season than the wet season, presenting a decrease in air temperature. This variation is due to the complexity of weather conditions and physical characteristics of the various urban elements. The lower monthly air temperature during the dry season was due to the influence of global radiation, which was lower in the dry season than in the wet season. The higher temperatures for the Unicampo site, especially at night, presumably resulted from higher humidity that should reduce longwave radiative cooling through a stronger greenhouse effect in the humid season. Moreover, water areas could reduce air temperature significantly during the daytime, especially at noon [14], however in general, average monthly temperature at the Unicampo site was similar to that of other sites. Maximum daytime values and average daily relative humidity were observed during January-March and October-December and minimum values were observed during August-September 2007

(Fig. 2). Relative humidity was ~20% less in the dry season. A feature of an urban center is that it is different from a nearby rural area. In general, a typical situation is that the center of a city is hotter than the surroundings. To compare differences in air temperature of the four sites, one needs to consider that the air temperature inside the site usually depends on the shading intensity of a partial shaded area, the thermal properties of the soil and the air temperature of its immediate background [14]. Because of this, it considers the Center site as the reference temperature in Fig. 3, which shows a decrease in air temperature (T) based on the Center site for each month. It is noted that there were no negative values, which means that the monthly average air temperatures at the center were the highest for the year in relation to other sites. The Chapada site, located at an altitude of 809 m, showed a low difference in air temperature of 1.4 °C in September (Fig. 3). However, during the dry season, the CPA site behaved to the contrary of the Chapada


895

Fig. 3 Difference in solar radiation, air temperature and relative humidity between Center and other sites for each month from January to December 2007.

site, which decreased the differences in tempreture at the Center site. Because solar radiation is similar for the Unicampo and CPA sites (Fig. 3), it would seem that smoke particles reducing the solar radiation are not the determining factor in creating temperature differences between the two sites. Like in Ref. [14], it considers the urban area to be influenced by a number of factors which complement each other in overall thermal behavior: physical characteristics of the various urban elements, the sky view factor, surface geometry, color and weather conditions. Compared with the Center site, the other three sites showed differences in air temperature ranging between 0.37 °C and 1.28 °C. Probably the

most dominant surface element contributing heat to the city is bare concrete cover, which is exposed to solar radiation and has no evaporative cooling effect over this kind of surface [15]. Solar global radiation was minor in the Chapada site reaching a maximum difference in July (150 W·m-2) (Fig. 3). 3.2 Distribution of Daily Clearness Index Daily clearness index KT (the ratio of daily global horizontal radiation to daily extraterrestrial horizontal radiation) values for all the days of 2007 for the four sites have been shown in Fig. 4. For the four locations, the KT presented seasonality, with lower values during

896


Fig. 4 Average daily clearness index (KT) for Center, CPA, Unicampo and Chapada sites from January to December 2007. Clearness index values between the dashed line and dotted line represent a partly cloudy sky. KT values above the dashed line represent a clear sky, and KT values below the dotted line represent a cloudy sky.

the dry season than the wet season. The Chapada site presented the lowest KT values possibility the aerosols being washed out by rain. In addition, higher cloudiness during the wet season reduced the average incident radiation less than the smoke in the dry season (Fig. 4). Moreover, the lack of rainfall would not reduce solar radiation at the surface; rain-producing clouds should in fact reduce the incoming sunlight. In this region, a stronger aerosol production (for

example through fires) occurred during the dry season. For the four sites studied, the cleanest days (or days demonstrating the cleanest conditions within the classification of partly cloudy) were often during the wet season, due to washing the particles from the atmosphere by pluvial precipitation (days 1-100; days 260-365; Fig. 4). Fig. 5 shows the frequency of days in the year based on the classification of sky cover for the four sites. The highest percentage of sky cover was partly


897

zero, classifying these conditions as a cloudy sky. For 0.3 ≤ KT ≤ 0.65, diffuse and direct irradiation is similar, this condition is called partly cloudy. And finally, in clear sky conditions when KT > 0.65, the direct global irradiation is at maximum, while diffuse radiation tends to be minimized [16].

Fig. 5 Daily frequency of sky covers classification for Center, CPA, Unicampo, and Chapada sites.

cloudy for the four sites studied. The Center, CPA and Unicampo sites were located within Cuiaba city. These areas have a lower altitude and are situated in or close to urban areas. The Chapada site is an area with a high altitude in an area located near a public park nature reserve. In this site there were no clean days and it presented a high percentage of cloudy days (days 130-212, Fig. 4). For the city of Botucatu, São Paulo-Brazil, a graphical comparison of global radiation, direct and diffuse horizontal incidence has been made. In the range 0 < KT < 0.3, the global and diffuse irradiation was practically equal and direct irradiation is close to

3.3 Distribution of Daily Extraterrestrial Radiation and Solar Radiation Fig. 6 shows the daily extraterrestrial radiation (Ro) and incoming solar radiation for the four sites studied in 2007. The highest value of daily extraterrestrial radiation obtained in March was 36.57 MJ·m-2·day-1 (day 71, Fig. 6) and in October was 36.00 MJ m-2·day-1 (day 275, Fig. 6). The lowest value occurred in June at 32.24 MJ·m-2·day-1 (day 174, Fig. 6). The maximum value of daily incoming solar radiation was 26.2 MJ·m-2·day-1 (day 358, Fig. 6) at the CPA site and was 22.1 MJ·m-2·day-1 (day 60, Fig. 6) at the Chapada site. Solar radiation is characterized by short fluctuations introduced by passing clouds. An analysis of these fluctuations with regard to solar energy applications should focus on the instantaneous

Fig. 6 Average daily solar radiation (solid line) and radiation in the upper atmosphere (dashed line) for Center, CPA, Unicampo and Chapada sites from January to December 2007.

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clearness index. The effect of changes in cloudiness on a number of environmental variables is frequent. On cloudy days, global solar radiation received by an ecosystem decreases, while the diffuse radiation received by an ecosystem increases [7]. Its probability distribution for a given mean clearness index is, at first glance, independent of the season and also partly of the site. Moreover, Cuiaba region during the dry season has been influenced by the intense amount of particulates in the air as a consequence of burning and the difficulty in the passage of radiation through the atmosphere. On the other hand, during the wet season with a greater likelihood of precipitation, there is a decrease passage of radiation due to the formation of clouds. Fig. 6 indicates that some factors can influence the reduction of radiation transmittance in the wet season. The wet season has the clearest sky conditions, even though it is still classified as partly cloudy. The

rainfall during this time of year is a wash of atmospheric particulates. 3.4 Correlation between the Daily Clearness Index and Micrometeorological Variables There was a strong correlation between the clearness index (KT) and air temperature (T) (Fig. 7a), during the wet season and it was weaker during the warmer months in the dry season. In March, despite the high correlation between them, the perfect negative correlation can be explained by a significant decrease in the clearness index at the end of March. During this time, there was a large amount of rain recorded at all measuring points and did not reflect a decrease in air temperature. The correlation between the clearness index (KT) and relative humidity (RH) (Fig. 7b) was consistent with Fig. 7a, by varying the inverse relationship between air temperature and humidity.

Fig. 7 Pearson correlation between (a) clearness index and air temperature; (b) clearness index and relative humidity during 2007.


Variations in meteorological variables for the four sites studied were strongly linked during the wet season (January, November and December) with a decrease in the warmer months of the dry season. In March and February, the low correlation can be explained by a significant increase in the relative humidity at Unicampo and Chapada and a decrease in the clearness index (Fig. 4) at the end of March as a result of the large rainfall recorded at all measuring sites.

4. Conclusions and Future Research Our data suggest that the more urbanized site, in this study, the Center site, had higher air temperature values than other sites with a lower building density. The Chapada site located at an altitude of 809 m had a higher air temperature possibility as a result of diffuse radiation, whereas the incoming solar radiation was less than other sites. The authors conclude the wet season demonstrated clearer skies than the dry season because the rain cleared the particulates from the sky. During the dry season, there was an increase in partly cloudy and cloudy sky conditions due to an increase of particulates in the atmosphere, as a result of burning in this region of the state. This work is of great importance because even though this region had high rates of radiation, it was influenced by atmospheric conditions which alter the energy potential of the region. Future research should aim to better quantify the measurements taken inside an urban area, considering the topography and vegetation cover. This would improve models that support urban planning, therefore favoring thermal comfort areas already occupied or to be urbanized.

Acknowledgments Support was provided by the Fundação de Amparo em Pesquisa em Mato Grosso (FAPEMAT), and the Federal University of Mato Grosso, Cuiabá-MT

899

(UFMT).

References [1]

C.A. Righi, P.M.L.A. Graça, C.C. Cerri, B.J. Feigl, P.M. Fearnside, Biomass burning in Brazil’s Amazonian “arc of deforestation”: Burning efficiency and charcoal formation in a fire after mechanized clearing at Feliz Natal, Mato Grosso, Forest Ecology and Management 258 (2009) 2535-2546. [2] R. Bariou, Colonisation Agricole et Peuplement en amazonie matogrossense, in: V. Dubreuil, R. Bariou, G.T. Maitelli, M.M. Dos Passos (Eds.), Remote Sensing and Environment in Brazil, Rennes, Pu Rennes, 2002, pp. 65-85. [3] M. Benzerzour, V. Masson, D. Groleau, A. Lemonsu, Simulation of the urban climate variations in connection with the transformations of the city of Nantes since the 17th century, Building and Environment 46 (2011) 1545-1557. [4] O.D. Corbella, M.A.A.A. Magalhães, Conceptual differences between the bioclimatic urbanism for Europe and for the tropical humid climate, Renewable Energy 33 (2008) 1019-1023. [5] A. Mellit, S.A. Kalogiroub, S. Shaaric, H. Salhid, A. Hadj Arabe, Methodology for predicting sequences of mean monthly clearness index and daily solar radiation data in remote areas: Application for sizing a stand-alone PV system, Renewable Energy 33 (2008) 1570-1590. [6] A.P. Souza, Developments, fractions and estimates of global radiation, direct and diffuse on inclined surfaces, Dissertation, State University Paulista, 2009. [7] M. Zhang, G.R. Yua, J. Zhuang, R. Gentry, Y.L. Fu, X.M. Suna, et al., Effects of cloudiness change on net ecosystem exchange, light use efficiency and water use efficiency in typical ecosystems of China, Agricultural and Forest Meteorology 15 (2011) 803-816. [8] V.M. Silva, Influence of sky coverage in the estimation of solar radiation using a digital elevation model, Dissertation, Federal University of Mato Grosso, 2011. [9] R. Kumar, L. Umanand, Estimation of global radiation using clearness index model for sizing photovoltaic system, Renewable Energy 30 (2005) 2221-2233. [10] W. Tian, Y. Wang, J. Rena, L. Zhua, Effect of urban climate on building integrated photovoltaics performance, Energy Conversion and Management 48 (2007) 1-8. [11] J.C. Dalponte, E.S. Lima, Availability of fruits and diet Lycalopex vetulus (Carnivora-Canidae) in a cerrado of Mato Grosso, Brasil, Revista Brasileira de Botânica 22 (1999) 20-22.

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[12] G.T. Maitelli, S.R.F. Vilanova, The importance of preserving green areas remaining in the political and administrative center of Cuiabá-MT, Uniciências 13 (2009) 13-18. [13] R. Dallacort, R.P. Ricieri, S.L. Silva, S.L.F. Paulo, F.F. Silva, Analysis of the behavior of a bimetallic actinograph (R. Fuess-Berlin-Steglitz) in different types of covering the sky, Acta Scentiarum Agronomy 26 (2004) 413-419. [14] L. Huang, J. Li, D. Zhao, J.A. Zhu, Fieldwork study on

the diurnal changes of urban microclimate in four types of ground cover and urban heat island of Nanjing, China, Building and Environment 43 (2008) 7-17. [15] C. Rosenzweig, W.D. Solecki, L. Parshall, M. Chopping, G. Pope, R. Goldberg, Characterizing the urban heat island in current and future climates in New Jersey, Environmental Hazards 6 (2005) 51-62. [16] R.P. Ricieri, Model estimation and evaluation of methods of measurement of diffuse solar radiation, Thesis, State University Paulista, Campos de Botucatu, 1998.


D

DAVID

PUBLISHING

Development of a Disaggregated Hybrid Model for Life Cycle Assessment and De-manufacturing Spivak Alexander and Matthew Franchetti Department of Mechanical, Industrial and Manufacturing Engineering, University of Toledo, Toledo 43606, Ohio, USA Received: May 18, 2012 / Accepted: May 30, 2012 / Published: July 20, 2012. Abstract: The de-manufacturing stage is an overlooked component of most current LCA (life cycle assessment) methodologies. Most of the current LCA techniques do not fully account for the usage of the product and end of life aspects. This paper introduces a comprehensive methodology that takes strong consideration of the inventory costs of use and end of life of the functional unit by combining manufacturing and de-manufacturing into the centerpiece of the hybrid analysis. In order to obtain this goal, a new disaggregated model was developed by enhancing current LCA hybrid methods related to life cycle inventory compilations. The new methodology is also compared to existing methodologies. Key words: Disaggregated hybrid, hybrid life cycle analysis, life cycle analysis, LCA (life cycle assessment).

1. Introduction Industrialization has changed the contemporary landscape and the environment. Attitudes towards environmental protection and conservation have improved. Manufacturers are showing increased concern as related to the final disposal and the emissions from the products that they produce, including recycling, de-manufacturing, and reusing. The ISO 14040 series provide methods for determining and reducing environmental pollutants. Due to the increasing trend in environmental legislation, which is leading to tighter regulations on pollutants [1] and the possible future introduction of carbon cap-and-trade regulation [2], manufacturers examine more effective ways to reduce their overall environmental impact, including GHG (greenhouse gas) emissions. LCA (life cycle analysis) is a useful tool to estimate GHG emissions over the entire lifetime of a product or service. Several LCA methods have been developed 

Corresponding author: Matthew Franchetti, Ph.D., assistant professor, main research fields: solid waste analysis and minimization. E-mail: [email protected].

and are commonly used in industry. Several research studies provide overviews of these various LCA methods [3]. Currently practiced LCA methods, such as process-based LCA, IO-based LCA, tiered hybrid, IO-based hybrid and integrated hybrid lack proper integration of de-manufacturing into the analysis. De-manufacturing stage included in publications is either limited to generic/IO data [4, 5], limited data [5], or discussed multiple options of end of life [6]. In either case, there is no effective way to link specific changes in designing/handling of the functional unit which would directly affect environmental inventory associated with de-manufacturing. Disaggregated hybrid links specific manufacturing and de-manufacturing process to specific functional unit. Most of the current techniques do not take into account the usage of the product and end of life of product aspects, or limit such applications [7]. A recent study found that de-manufacturing accounts for up to 20% of all GHG emissions, but less than 5% of all data points used in the calculation of LCA models [8, 9]. De-manufacturing is typically collected from average data sets or partially acquired from various sources, instead of being directly related to the

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Development of a Disaggregated Hybrid Model for Life Cycle Assessment and De-manufacturing

de-manufacturing process. For example, a recent LCA study in the home building industry [8] concentrated predominantly on the construction stage, but only took a few flows from the demolition stage. Another study [9] concentrated exclusively on the demolition stage of the life cycle. Such studies, while being valuable for their purpose, did not completely model the life cycle of the building construction. In order to mitigate such problems, a new methodology was proposed. The objective of this research was to create a hybrid LCA model that better accounts for de-manufacturing processes. It collected comprehensive data from both manufacturing and the de-manufacturing and treated both data sets as a single process analysis data. Such an approach allowed a more comprehensive optimization of the LCA and emphasized “design for de-manufacturing” as an important, but mostly neglected component of the LCA process. In addition, such an approach aided to compile a more precise evaluation of the environmental inventory generated by the entire life cycle of a functional unit.

2. LCA Hybrid and Disaggregated Hybrid Overview LCA hybrid methods combine both PA (process analysis) and IO (input-output) analyses in order to obtain a more complete picture of the environmental impact generated by the process. The general goal of the hybrid analysis is to combine the advantages of IO and PA methods [8]. IO analysis has more complete boundaries, while PA is more specific and process related. The hybrid method is the best method for a comprehensive and robust analysis as it combines the benefits of IO and PA methods [10]. Unlike PA and IO methods, hybrid methods cover all sections of economy including the sector level and process level, allowing a more comprehensive estimate of the environmental impact of the unit process. Hybrid method’s boundaries may include entire energy production and consumption cycle. In addition, it

distinguishes between direct and indirect use of energy [11]. Decomposition analysis has proved to be a useful tool for analyzing changes in energy consumption [11]. A few studies also decomposed changes in emissions [12, 13]. The decomposition analysis is a method that allows determing the effect of changes upon the output of the LCA. Three hybrid methods are most prominent. These methods are the tiered, IO-based, and integrated hybrid methods. The simplest hybrid method of the three is a tiered hybrid. It has a relatively complete upstream boundary obtained typically from the IO databases while the PA-based part provides more specific near upstream and the downstream boundaries [14, 15]. The IO and PA-based demands are separated [14]. This means that there is no direct interaction between IO and PA-based technology matrices and no direct interaction between IO and PA-based demand vectors. The former is, however, subjective, since interactions between the process and IO may be built into the values. Such interactions would result in double counting of the environmental inventory. There are many examples of the tiered hybrid analysis in the literature. Some of them are Refs. [8, 11, 16-18]. Tiered hybrid calculations may be conducted in two different ways [14]. They are: (1) Processes are in principle modeled in the IO part, and processes are not covered by the IO table, mainly consumption and waste treatment, are modeled in the PA part [7, 14, 17, 18]; (2) Processes around the production and consumption stages are modeled in the PA part (as “foreground” processes), and processes further upstream and downstream in the IO part (as “background” processes) [14, 19, 20]. The main strength of the tiered hybrid analysis is the relative ease of use (simple application that may be completed using a spreadsheet application, nearly complete upstream system boundary, and availability of software tools) [16, 21]. Weaknesses include the problems of double counting and relatively limited accuracy since IO matrices only use industry-by-industry data and technological system


boundary completeness depends upon the shares of PA- and IO-based system [21]. The IO-based hybrid, just like the tiered hybrid, has no direct interaction between IO and PA-based matrices. The only connection between the two is final demand vector. The key difference is that an IO-based hybrid uses augmented matrices on the IO side. The main strength of the method is a consistency of process and IO data (domestic data only), which helps to avoid double counting, and nearly complete upstream system boundaries by augmenting the IO data to include missing information. In addition, there is an abundance of special computational software packages (e.g., MatLab®), some of which, however, may be expensive [21]. Weaknesses include relatively limited accuracy, since IO matrices only use industry-by-industry data and technological system boundary completeness depends upon the shares of PA- and IO-based system. Also, in this method the end-of-life phase is externally added to the main system [21]. Joshi [7] discussed six models of the IO-based method. They are: (1) approximate product by its sector; (2) product as a new hypothetical sector; (3) disaggregating an existing industrial sector; (4) iterative disaggregation of an existing industrial sector; (5) inclusion of the use phase of product LCA; and (6) inclusion of the end-of-life management options. Integrated hybrid, unlike the previous two methods, links both IO and process-based matrices using X and Y upstream and downstream cutoff matrices that show commodity flows from IO system to process-based system and from the process-based system to the IO system. Similarly to other methods, the technical PA matrix’s units are shown as physical units per operation time of each process and the IO matrix units are monetary. This method, in theory, considers all relationships between the IO and PA components of the functional unit. For example, in the lime production industry, it considers both use of energy in the production of steel and use of steel in the

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production of energy and their interactions from both financial and process standpoints. Such a technique presents a more accurate picture of the true environmental inventory, but is very expensive and time consuming. Other hybrid methods or variations are used to the lesser degree. In addition to discussion of the three main methods, this paper will mention an augmented hybrid. Hybrid methods are similar since they combine PA and IO methods in some ways, and they differ primarily on approach of interpretation of incoming and outgoing streams (i.e., proportions of IO and process data, level of augmentation of IO data, inclusion of cutoff matrices, etc.). The disaggregated hybrid method incorporates some components of each of these hybrids, concentrating predominantly on manufacturing and de-manufacturing components of the functional unit analysis. The disaggregated hybrid, like many LCA methods, is designed to help practitioners optimize the environmental inventory associated with a functional unit, while complying with ISO requirements. The suggested major change that generates the disaggregated hybrid is aimed at improving current hybrid methods by combining the manufacturing and de-manufacturing stages into a single process. This accomplished by either considering estimated environmental inventory of the product, as it would be de-manufactured at the end of its useful life by either considering existing product’s or similar product’s de-manufacturing stage. If existing product is similar to the products that are being de-manufactured at the current time, it is possible to estimate the environmental inventory of its de-manufacturing based on the current de-manufacturing process (in the mature industry). Alternatively, estimation would involve greater number of assumptions. Usually, the sector-wide data are used on the upstream side of the process. On the manufacturing side and downstream side, either specific process data or sector-wide data are used, depending on application.

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However, the bulk of the data is typically collected at the manufacturing stage, under-representing or over-generalizing the rest of the LCA analysis, especially downstream processes as displayed in Fig. 1. In the disaggregated hybrid case, the manufacturing and de-manufacturing stages are the centerpiece of the hybrid analysis where most of the process data are collected. De-manufacturing process data are just as critical for the overall LCI data as the manufacturer’s data. Use of both sets of data in the model creates an alternative interpretation of stages of hybrid analysis as displayed in Fig. 2. The primary differences between traditional LCA methods and the disaggregated hybrid method relate to the detailed inclusion of both manufacturing and de-manufacturing. Such addition is necessary in cases when the product is designed with de-manufacturing in mind. The minimization of the sum of the environmental inventories of manufacturing and de-manufacturing is more important goal than minimization of environmental inventory of the manufacturing only (assuming that de-manufacturing data are generic IO data). This is reflected as a general concept behind design for de-manufacturing. For

example, if a wooden box is made with nails instead of screws, the environmental burden associated with production will be smaller (assuming a pneumatic nail punch uses overall a lesser amount of resources than an automatic screw driver, and nail production uses lesser resources than production of screws). Therefore, based on the LCA analysis, which accounts predominantly for manufacturer’s processes, practitioners may conclude to use nails instead of screws. However, a disaggregated LCA analysis studies environmental inventory of removing nails versus screws may show that screws are the better overall option. Such an approach eliminates a two-tunnel optimization problem.

3. Methodology The mathematical model of the process component of the disaggregated hybrid is based on the PA methodology adopted from hybrid compilations. The methodology was discussed in several books and papers, but predominantly in books and publications of Suh. Eqs. (1-5) presented in the following section are based on Heijungs and Suh [14, 21, 22], but adopt disaggregated hybrid. This section will discuss the

Fig. 1

General stages of the hybrid analysis of the manufactured functional unit.

Fig. 2

General stages of the disaggregated hybrid analysis of the manufactured functional unit.


differences and enhancements of the current methodology and applications of certain techniques to various specific cases of the disaggregated hybrid.

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material use stages, which generally includes energy consumption over the life cycle of the functional unit. In products that consume large amount of energy over their lifetimes (such as vehicles), this stage is critical

3.1 General Case Scenario

during the design and manufacturing part. For

Currently used hybrids consider manufacturing

products, that do not consume significant or any

processes as a centerpiece of the analysis, while

additional energy (such as furniture), the life use stage

centerpiece of the disaggregated hybrid analysis is a

is very limited, often negligible, important. Some of

combination of manufacturing and de-manufacturing

the materials that are used for the de-manufacturing

processes. The technology matrix used in the literature

will often be similar to the ones used for the

may include following components:

manufacturing of the functional unit. For example,

(1) Technology flows:

electricity (at least in form of lighting) is used in both

 material(s) used for production (negative flows);

stages. If sources of electricity are sufficiently similar

 material(s) produced;

and temporal factors are not significant, it is possible

 materials disposed (special case: recycling,

to combine both units of electricity into a single data

closed loop recycling).

point with little or no allocation adjustments. Such

(2) Environmental flows:

compilation simplifies the optimization of overall

 material(s) used for production (negative flows);

environmental inventory of functional unit over its

 material(s) produced;

entire life cycle.

 materials disposed (special case: recycling, closed loop recycling). If

processes

The structure of the process inventory

~ P

can then

be represented by combination of economic/process of

manufacturing

and

de-manufacturing are integrated, the technology

flows,

~ ~  A P   ~ B

components:  material(s) used for production (negative flows);  material(s) produced;  material(s) used for disassembly (negative flows, less recycled into production);  material(s) disposed (special case: recycling, closed loop recycling). (4) Environmental flows:  material(s) used for production (negative flows);  material(s) produced;  material(s) used for disassembly (negative flows, less recycled into production);  material(s) disposed (special case: recycling, closed loop recycling). In addition, hybrid methodology accounts for the

, and environmental flows,

~ B

, as shown in

Eq. (1):

matrix (a square matrix) will include following (3) Technology flows:

~ A

   

(1)

Economic/process flows and environmental flows are well defined by Heijungs [22], whose book equations were adopted for the disaggregated hybrid. 3.2 Inventory Problem in the Disaggregated Hybrid’s PA Component When looking at the inventory problem, a specified required performance of the system, known as reference flow (or flows), is arbitrarily chosen. If a ~

single reference flow is chosen, it may be a vector k

with all values of “0” except one, the amount of ~

product required. If k i units of product are considered, external demand (final demand vector) appears in Eq. (2):

906


~ g~u  B ~ su

 0       ~ ~ ku   ku i        0    is in the product row of

where k~i

(2)

in manufacturing

and de-manufacturing processes. In the disaggregated hybrid

~ ku

considers a number

of the functional units that are expected to undergo de-manufacturing.

If

de-manufacturing

is

not

considered, disaggregated hybrid method does not need to be applied, then k~u  k~ . It is important to notice that such consistency is not possible, when manufacturing and de-manufacturing are treated as individual process. In that case, demand vectors will be subject to independently determined units of flow (for example, k~1 units manufactured per time, and k~2 units de-manufactured per time). When both processes are unified as a single process, a single reference flow, k~u , or a set of reference flows may be chosen, eliminating the need for re-scaling and reducing associated with truncation errors. The unified scaling factor, ~su , may then be introduced as displayed in Eq. (3):

~ 1 ~ ~ 1 ~ ~ su  Am k u  tAd k u

(3)

where, subscripts m and d stand for manufacturing and de-manufacturing, respectively, and scalar t refers to estimated

temporal

adjustment

of

the

process

technology matrix of the de-manufacturing process. Such

adjustment

may

be

From which the intensity matrix, Λ, may be calculated as shown in Eq. (5):

~ g~u  k u

~ A

based

on

current

de-manufacturing inventory of the similar or identical functional unit adjusted for expected changes in de-manufacturing technology at the end of its useful life. This method allows considering both economic and environmental costs of de-manufacturing of the functional unit during the design stage. Then, scaling factor may be used to define environmental inventory vector, g~u , which accounts for the total amount of materials released into the environment as displayed in Eq. (4):

(4)

~~    B A 1

(5)

The latter is important for problems with missing information (cut-off problems). Heijungs [14] suggested that the best approach for these types of problems is to divide Λ1 × k into solvable Λ1-m and unsolvable Λm-k vectors (or matrices). This is especially important for disaggregated hybrid, since information from the de-manufacturer may be delayed and changes can be made at the later time to adjust for the missing information. The goal that is unique to the disaggregated hybrid would be to minimize de-manufacturer’s component of Λm-k. 3.3 Inventory Analysis Model of Process Component of the Disaggregated Hybrid As discussed earlier, cut-offs are results of incomplete knowledge of the product flows between the processes. Permissible cut-offs are subject to some interpretation. However, general rules and some specific cases are discussed in LCA guidebooks [23]. In the disaggregated hybrid, cut-offs may not include entire end-of-life process. If that occurs, disaggregated hybrid becomes similar to existing hybrid methodologies. Cut-offs may include large parts of upstream processes, but should be limited on the downstream side whenever possible. Among methods that deal with cut-offs, removing cut-off flows from the technology matrix into a separate matrix best suits disaggregated hybrid. This is the only approach that does not generate wrong information and does not nullify any information as well. In addition, if some information come later, the data from separate matrix Λm-k may then be moved to the matrix Λ1-m. Addition of zeros method may reduce the value of disaggregated hybrid, since it removes information which may be completed at the later time. The technology matrix is then separated in solvable

~ ~ A * and unsolvable A ** components.


3.4 Removing Cut-Off Flows in the Disaggregated Hybrid The term “removing cut-off flows” is misleading [14]. As discussed earlier, cut-off flows are separated ~ from the technology matrix, A , and placed into matrix ~ ** A (Eq. (6)). ~ ~  A* A   ~ **  A

   

where final demand vector:

~  ku* ~  ku    0

   

(6)

where, reference flow is part of the “solvable” matrix.

~

~

Then A * and A ** are defined by following Eqs. (7-9):

~ * 1 ~ ~ * 1 ~ ~ su  Am k u  tAd k u ~ g~u  B~ su ~ ** ~ ** ~ k u  A su

(7) (8) (9)

~ The final supply vector, ku , is then represented

using Eq. (10). ~ ~*  ku*   A  ~ ~  (10) k u   ~ **    ~ **  ~ su  A ~ su A k   u   ~ and discrepancy, d , between imposed final demand, ~ ~ k u , and obtained final supply, k u , is displayed in Eq. (11):

~ ~ ~ d  ku  ku

(11)

The two main methods applied for allocation used in the literature are substitution and partitioning [14]. Both methods are designed to overcome the problem ~ ~ of over-determined system A -1 k~u by turning A into a square matrix. Such technology matrix in the disaggregated hybrid includes following components:  material(s) used for production less material(s) reused;  material(s) produced;  material(s) consumed during the useful stage;  material(s) used for disassembly/chemical treatment;  material(s) disposed;

907

 material(s) recycled;  transportation;  storages. One must be careful how to treat the case if:  Material used for production is similar to materials generated through recycling or de-manufacturing;  Multiple methods of (for example) transportation are used;  Multiple methods of storage are used;  Electrical (and other) energy is obtained from multiple sources. In the substitution method, a quality adjustment takes place. It is applicable to all of the three cases above. For example, a material y, which is 90% as good as material x, may be treated as t = 0.9(x). In disaggregated hybrid, unlike other methods, material y may not necessarily be produced on site, but rather generated as result of disassembly of functional unit. In this case, rows of transportation and storage may need to be adjusted to include treatment of material Y. The allocation of transportation and storage is accomplished in the same way, where “quality” is a factor of location, change in quality of perishable material, time, type of transportation, storage energy usage, etc.. Partitioning method also works well with disaggregated hybrid. Since end-of-life component may be disaggregated into parts using production allocation factor λ as:  recycling    disposal    de  manufactur ing   ... where ή is associated with production matrix, and identical expression with μ instead of ή is associated with environmental matrix. A basic feature of each production allocation factor is displayed in Eq. (12): a



b

c

   1, which also means that

0    1

(12)

a

One must be careful not to oversimplify flows and avoid surplus method, where major flow takes almost all resources, as it would limit the purpose of

908


disaggregated hybrid, where some of the end-of-life processes are treated as a set of major flows in the same way as the manufacturing stage. 3.5 Closed Loop Recycling in the Disaggregated Hybrid A closed loop recycling method may be used when the

secondary

material

produced

by

a

de-manufacturing process which is completely fed back into one manufacturing process. In such case allocation is not required. In disaggregated hybrid closed loop recycling includes (unlike other hybrids) a material

that

is

transported

back

from

the

de-manufacturing facility into the manufacturing facility. The disaggregated hybrid distinguishes two different types of the closed loop recycling: a traditional type, that occurs within a single facility and a type described above. Examples of the first type of closed loop recycling are: aluminum that is left after the stamping is fed directly into the oven and the glass from the window broken on the plant’s floor is crushed and returned into the oven. Unlike current methods, the disaggregated hybrid also allows closed loop recycling if glass from the old window is crushed by the de-manufacturer and sent back to manufacturer of the new window. However, additional processes of transportation and storage of such glass must be taken into consideration. This enhancement

allows

practitioners

to

use

3.6 Computational Structure of IO Component of the Disaggregated Hybrid In previous sections the discussion was limited to manufacturing process and downstream processes. The other component of the disaggregated hybrid is IO data. It is predominantly used in the upstream process and as needed in the other sections of the analysis (including manufacturing and de-manufacturing). IO components in the disaggregated hybrid may be augmented in the similar way as in IO-based hybrid. Unlike other hybrids, IO components of de-manufacturing are treated the same as IO components of manufacturing. This assumption may require introduction of the sector-wide de-manufacturing database similar to the one existing for the manufacturing sectors. The IO component of the disaggregated hybrid does not require adjustment by scalar t, since it is generic by definition. Just like in any other hybrid [14], technology matrix’ inputs and outputs are formulated in terms of flows of products, while transaction matrix inputs are formulated in terms of other processes’ outputs. The matrix’s coefficients are presented in monetary values. The technical coefficient matrix, A, is defined in terms of fractions aij , where A is shown in Eq. (13): 

A | aij | , where a  ij

ISO-recommended closed loop recycling scheme, which eliminates errors associated with allocation. However, a practitioner must conduct a sensitivity

z a 1



z a 1

ia

ia

(13)

k

where z is transaction value between processes and ku is a unified demand by the producer/customer

errors associated with “quality” of material are greater

vector. Then, total output vector, a, is defined by Eq. (14):

or smaller than errors associated with cut-off values

(14)

analysis in each individual case and compare whether

and truncation of data. Lenzen [24] examined aspects

a  ( I  A) 1 ku

considered only in cases where materials are

where, I is an identity matrix. Since matrix B is structurally identical to intervention matrix B in inventory PA, then environmental intervention associated with customer demand, gu , is defined by

sufficiently similar.

Eq. (15):

of latter errors, and created a background for such analysis. It is suggested that closed loop recycling be


g u  B( I  A) 1 k u

(15)

4. Theory and Structure The application of disaggregated hybrid requires a higher degree of cooperation between the manufacturer and the de-manufacturer. The disaggregated hybrid may take more than one form, depending on amount and type of information that is available. The critical part of the disaggregated hybrid is the presence of additional end-of-life process data. Therefore, the disaggregated hybrid method is not applicable to most service-based functional units and functional units that can not be de-manufactured. Types of disaggregated hybrid discussed in this paper are:  tiered disaggregated hybrid;  IO-based disaggregated hybrid [7]. The general structure of the disaggregated hybrid consists of the process and IO components. The Equation of the total environmental burden (total environmental inventory) is displayed in Eq. (16):

I Total  R  T  P  L  D  E

(16)

where total environmental inventory (ITotal) is a sum of all inventory generated from production of the raw materials, R, transportation, T, production, P, life use, L, de-manufacturing, D, and end-of-life, E. Process components are based on traditional matrix, where

~ A is a disaggregated process-based technology matrix

as shown in Eq. (17): ~ An  n 

a~ 1 ,1  ~ a n ,1



a~ 1 , n



 ~ a n ,n

They may be expanded into Eq. (18): a~1,1  a~1, n 

 ~ ~ Ar  r  a n ,1  ~ a r ,1

   

 ~ a n ,n



 ~ a r ,n



 

909

indicate the values of the de-manufacturing process. The IO components expansion depends on the application of the disaggregated hybrid. If IO data are used predominantly upstream, only a general n × n matrix is used. A special case of IO-based disaggregated hybrid method expansion is discussed further in the section. The general IO matrix is shown in Eq. (19):

a1,1  a1,n

An  n  



(19)

an ,1  a n ,n Hybrid methods, as discussed in the literature review, have both A and Ã components, where A is an IO technology matrix and Ã is a process-based technology matrix. The dependency in Ã matrix between ãij values is the same as in A matrix. Unlike A matrix, Ã matrix is not obtained from the sector-wide data, but rather from the process itself. The ãij values are based on inflows and outflows of commodity i of process j for the certain duration of process operation [16, 25], while aij is defined as dollar value of input required from sector i to produce $1.00 worth of the output in sector j. In other words, the differences between A and Ã matrices is a level at which data are obtained (sector-wide level vs. process level) and direct vs. indirect use of dollar-based analysis. In cases where data from the IO sectors are replacing “missing” data from PA sector (or vise-versa), both matrices describe the same functional unit, if A matrix

(17)

is r × r, then Ã matrix will be r ×r, too. Environmental IO and process data matrices are Bq × n

a~1, r  ~ a n ,r

~

= |bij| and B q

× n

~

= | bij |, respectively. Matrix B

shows the amount of pollutants or natural resources (18)

 ~ a r ,r

by combining manufacturing and de-manufacturing processes into the single centerpiece of the process component. The new rows and columns n through r

emitted or consumed to produce unit monetary output

~

of each industry [16, 25], and matrix B shows the amount of pollutants or natural resources emitted or consumed by specific process over the specified period of time. Just like values in A matrices, in B matrices may be augmented. Equations that would relate to them are similar to ones in the A matrix.

910


columns in square A matrix. Since the part of

of the centerpiece of the method. Because de-manufacturing is included, arbitrary scaling factors are re-calculated, using techniques shown earlier in the chapter. Eq. (21) displays disaggregated tiered hybrid’s structure:

calculations of the total environmental inventory is

(21)

Since the number of sectors (including hypothetical sectors involved in creation of A matrix) is the same as the number of industries in B matrix, then number of columns in B matrix will match the number of

~ multiplication of B by (I – A) and B by Ã-1, then if -1

A= |aij| is r × r matrix, then Ã=|ãij| is r × r matrix as well, since the same process is considered in both

~

cases. Then, using the same logic, B = |bij| and B = ~ | b ij | are both q × v matrices. Sectors/processes in Bqxn = |bij| matrices are disaggregated exactly the same way as in A = |aij| matrices. The side q (pollutants/resources) does not change from the original methods, since the same pollutants and resources are considered regardless of methodology. 4.1 Tiered Disaggregated Hybrid In the tiered hybrid, the direct manufacturing and downstream requirements (for manufacture, use and end-of-life), and some important near upstream requirements of the functional unit are examined by the PA [25, 26]. The remaining upstream (material extraction, etc.) requirements are examined by the IO analysis. Tiered hybrid also allows supplementing “missing” process data with equivalent IO data [8, 22, 25]. The tiered hybrid has the following structure shown in Eq. (20): M

TIERED

~ B   0

~ 0 A  B 0

0   I  A

1

~ k    k 

(20)

1 ~ ~ ~  B" 0  tA" 0  ku " M DISAGGREGATEDTIERED        0 B   0 I  A ku "

where ″ refers to the disaggregated matrix that includes both manufacturing and de-manufacturing processes, and t is a 1 × n matrix, where values for the manufacturing stage are equal to one and values for the de-manufacturing stage range are scaled based on the forecasted relative environmental inventory of de-manufacturing based on the product design and expected technology change over the lifetime of the product. In linear form, the disaggregated tiered hybrid is shown in Eq. (22). ~ ~ ~ M DISAGGREGA TED TIERED  B " (tA" ) 1 k u " B ( I  A) 1 k u " (22) Using Suh’s [21] structure of hybrids, the visual representation of the disaggregated tiered hybrid is represented in Fig. 3. where, Bold line shows overall system boundary; Dotted line shows the boundary between process-based system part and IO system part; Shaded area (outside) is IO system part; Gray area (inside) is process-based system part, which includes both process of assembly and process of disassembly and/or material or energy recovery.

where, B is an IO environmental matrix;

~ B is a process based environmental matrix;

A is an IO technology matrix; Ã is a process based technology matrix; k is an arbitrary IO final demand vector;

~ k is an arbitrary process based final demand vector.

Process components A and B are re-defined in the disaggregated tiered hybrid to include a combination of manufacturing and de-manufacturing stages as part

Fig. 3 hybrid.

Visual representation of disaggregated tiered


4.2 Disaggregated IO-Based Hybrid The IO-based hybrid starts with IO model which is augmented and to which available process data is added. The format of the IO-based hybrid is shown in Eq. (23): M

IO BASED

~ 0 A  B '  0

~ B   0

0   I  A ' '

1

~ k     k '

(23)

'

where augmented matrices A and B and vector k ' must include life and end-of-life components. In the disaggregated version, matrices are reorganized to include a combination of manufacturing and de-manufacturing stages. Such re-organization differs slightly from other hybrid applications and is discussed in more detail below. Life use and disposal of the specific product are discussed in the literature as separate sectors [7]. If the matrix A is an n × n matrix which is composed of components aij, then the result is displayed in Eq. (24): a 1 ,1 An  n 



 a n ,1

a 1, n 



(24)

a n ,n

where, aij represents financial effect of each sector upon the other. The effect of the sector upon other sector is measured in terms of dollars. It may be obtained from sector-wide data tables. As discussed by Joshi (Methods V and VI) [7], life and disposal analysis are treated as separate sectors. The data for these sectors are not as widely available, nor is being devoted sufficient attention in the literature. An IO-based hybrid extensively uses IO data. However, none of the sectors specifically addresses de-manufacturing processes. Some of the sectors may be augmented, and de-manufacturing is separated from them, if sufficient data is available. Yet, most of the de-manufacturing is not treated as a separate sector of industry. This lack of information makes IO-based disaggregated hybrid difficult to complete at the present time. In this section, the new methodology that includes the life and end of life of the functional unit is

911

discussed. By doing so, the entire vertical integration of product’s life is looked at. Such way of looking at the cradle-to-grave approach is arguably more consistent with ISO 14040 series standards than any other currently used method. However, it is important to notice that this technique is not designed for comparing products or services. It is only designed for optimization of entire life cycle of the given product or service. When life use and end of life of the product in question are considered, the matrix becomes Eq. (25): a 1 ,1 



a 1,n  2 

a n  2 ,1



a n  2 ,n  2

A(n2)  (n2) 

(25)

where (n+1) and (n+2) sectors correspond to life cycle and end of life of functional unit. However, life and end-of-life sectors, if information is available, may be disaggregated further. For example, the life of the passenger vehicles may be disaggregated into such sectors as gasoline consumption, oil consumption, replacement parts manufacturing, etc.. By disaggregating sectors, it generates a new matrix A(n+p) × (n+p), where p is a number of disaggregated sectors designed to describe life and/or end-of-life components of the functional unit as displayed in Eq. (26): a 1 ,1 A(n 2)  (n 2) 

a 1,n  p





(26)



a n  p ,1

a n  p ,n  p



The proposed methodology also disaggregates the matrix further to include environmental burdens of de-manufacturing creating a new Ar × r matrix which is displayed in Eq. (27):

Ar

 r

a 1 ,1



a 1,n



a 1,r



   



   



 a n ,1  a r ,1

a

n ,n

 a

r ,n

(27)

a n ,r  a r ,r

where (n+1) … (r) components correspond to life use and end-of-life environmental inventories of components of the functional unit, and (n+p+1)… (n+r) components correspond to de-manufacturing components that are not allocated into manufacturing part of the matrix. De-manufacturing sectors of

912


industry at the present time have not been developed into the list, making such calculation more difficult. Just like in previous cases, end-of-life values may be positive or negative depending on:  percent recycled;  percent reused;  percent disposed;  percent incinerated (energy use). Of each component of the functional unit, that is used specifically to make functional unit, but is not a part of the unit itself (e.g., use of oil to make electricity). Additional augmentation may include utilities, co-/by-products and other environmental burdens, if any. Such disaggregation is represented by the Av×v matrix, where v > r. One must be careful not to overstep the boundaries of the functional unit. a1,1  a1, r  a1,v      (28) Av v  a r ,1  a r , r  a r ,v      a v ,1  a v , r  a v ,v In the cases shown in Eq. (22) through Eq. (24), aij is disaggregated into components starting from each sector of the economy with process data added as necessary. In Eq. (22), the sector that includes the functional unit is disaggregated into up to five sub-sectors: raw materials, transportation, production, life use and end of life of the functional unit. Additional desegregation, such as augmenting sector with functional unit into multiple sub-sectors, is also discussed in Ref. [7]. Eq. (23) expands upon Eq. (22). In Eqs. (24) and (25), more than one sector, including one with functional unit, is disaggregated into five sectors mentioned above. In addition, a new set of de-manufacturing sectors are added. Such separation allows accounting for the end of life of the byproducts (both useful and waste) generated by the production/service of the functional unit, thus, bringing a more complete picture of the total environmental inventory associated with the

functional unit. Advantages and disadvantages of matrices 24 and 25 are discussed in detail further in the text. The total environmental inventory factor associated with complete life cycle of the functional unit or byproduct, aij (total), may be defined by the following formula as displayed in Eq. (29): aij (total) =traij (r) +tsaij (s) +tmaij (m) +tlaij (l) + tdaij (d) +teaij (e) (29) where, subscript (r) refers to environmental cost of raw materials; subscript (s) refers to environmental cost of transportation; subscript (m) refers to environmental cost of manufacturing; subscript (l) refers to environmental cost of useful life; subscript (d) refers to environmental cost of de-manufacturing; subscript (e) refers to environmental cost of end of life. Coefficient t is a temporal coefficient that may be taken into consideration to account for the interventions that affect environment over the significant length of time. In cases where time is not a significant factor, or not enough data is available, t may be set to value of 1. The environmental inventory of the end of life may be further separated into components via Eq. (30): (30) aij(e) = dcd + rcr + ucu + (1-d-r-u)cg where, d is the percent of the material/product that is being disposed; cd is an environmental cost coefficient of disposal. In the same way, “r” represents recycling, “u” represents “reuse” and “g” represents “energy recovery and any other alternative methods of completion of product’s life”. If Eq. (24) or Eq. (25)’s format is chosen, a single entry of aij changes from original (currently used in the literature) aij (p) into aij (total), where: (31) aij = aij (total) = (1-l-e)aij + laij + eaij


Or, with temporal factor coefficients aij = aij (total) = (1-l-e)aij + (tl) laij +(te)eaij (32) where, t refers to a temporal coefficient. By separating the types of the end-of-life environmental inventories, the following Eq. (33) is obtained: aij = aij (total) = (1-l-e)aij + (tl) laij +(te)aij[dcd + rcr + ucu + (1-d-r-u)cg] (33) The value of t may be either below or above 1, depending on original assumption: if t = 1 corresponds to the present time, then values t < 1 will correspond to the future, since environmental inventory is cumulative with respect to the time. Therefore, values of t > 1 will correspond to the past. It is reasonable to assume that rapid production will not sufficiently affect t. The exception would be a production of large items (typically single cell production), such as sea ship, where t within the manufacturing stage may become a factor. In equation format, the disaggregated hybrid is shown in Eq. (34): M DISAGGREGATED

1 ~ ~ ~  B" 0  tA" 0   ku "  (34)  IOBASED  (")   (")  (")    0 B'   0 I  A'  ku ' 

where ″ refers to the disaggregated matrix that includes both manufacturing and de-manufacturing processes, and t is a 1× n matrix, where values for the manufacturing stage are equal to 1 and values for the de-manufacturing stage range are scaled based on the forecasted

relative

environmental

inventory

of

de-manufacturing based on the product design and expected technology change over the lifetime of the product. Alternatively, the hybrid may be represented in the following format which is displayed in Eq. (35): ~ ~ 1 ~ (") (") 1 MDISAGGREGA )ku '(") (35) TEDIOBASED  B"((tA") )ku "B' (I  A' Using Suh’s [16, 21] structure of hybrids, the disaggregated hybrid would have the shape shown in Fig. 4. where, Bold line shows overall system boundary; Dotted line shows the boundary between process-based system part and IO system part; Shaded area (outside) is IO system part;

913

Fig. 4 Visual representation of disaggregated IO-based hybrid.

Gray area (inside) is process-based system part, which includes both process of assembly and process of disassembly and/or material or energy recovery; Crossed area indicates disaggregated (augmented) IO system, while uncrossed area refers to use and disposal processes only. 4.3 Model Assumptions There are a number of underlying assumptions related to the disaggregated hybrid methods. These assumptions must be taken into consideration when the analysis using this method is conducted. One of the assumptions of the method’s IO components is that original technical coefficient matrices are unaffected by introduction of new sectors. Since there is a theoretical interaction between all sectors, there is some levels of dependence of one sector upon another. However, as interaction effects diminish, they fall outside of the significance range. Such should be true for a vast majority of cases. Yet, it is important to notice that assumption will not hold in cases where functional unit is already included in existing commodity sectors and used as intermediate input in other sectors. This assumption prevents complete integration of the integrated and disaggregated hybrids. Another assumption is related to time factors. Time factors account for the effect of changes of time upon technical coefficients. Since only a single coefficient may enter into the matrix at one time, and only a single time adjustment multiplier (time discount rate) may be used, it is assumed that technical coefficient

914


matrix for the economy remains unchanged during the lifetime of the product. It is, however, possible to multiply each component of the matrix by additional time adjustment multipliers. Practitioner must decide whether such effort will yield significant changes. The proposed methodology allows reduction of allocation due to cyclical nature of recycling and energy recovery. The third assumption is that the material or energy generated at the end of life of the functional unit is equivalent or may be adjusted to match to the same amount of recycled material or energy that may be used during any stage of the functional unit’s life cycle. In other words, if 20 MJ energy is generated through energy recovery, while the functional unit consumes 30 MJ energy over the lifetime, only approximately 10 MJ energy loss will enter into equations. Such method of calculations is not necessary. However, since end-of-life calculations are prone to data availability and quality problems and likelihood of complicated allocation procedures [7], it is advised to use this assumption when calculations are performed.

5. Results and Conclusion This disaggregated hybrid method is an innovative and more comprehensive method of the environmental inventory compilation and LCA. The method incorporates applications from tiered hybrid through IO-based hybrid’s Method VI [7]. It also includes applications of Suh’s integrated hybrid [16]. It proposes re-definition of the boundaries of LCA analysis by combining manufacturing and de-manufacturing into a single centerpiece of the analysis. It allows PA-based calculations of the manufacturing/de-manufacturing process. Also it proposes a creation of new sectors for IO-based calculations of manufacturing/de-manufacturing process. The disaggregated hybrid method affects the allocation problem which is multiple ways. It reduces the allocation problem associated with separation of

the ancillary flows between the functional units. Also, it reduces the allocation by employing a full cycle (open-ended) recycling approach. The disaggregated hybrid methodology is generally more complete than any other method, because it includes an extensive incorporation of the life and the end-of-life stages as well as the de-manufacturing stage. The proposed methodology is a cyclical hybrid where the recovered recycled material and energy are accounted for in order to reduce allocation calculations. The comprehensive cradle-to-grave/cradle approach of the boundary setting allows the inclusion of the detailed process information with little double counting and within the consistent framework. However, such analysis comes with a price: it is difficult at best to both include large boundaries and process-specific analysis. In addition, such analysis is time and resource consuming. The disaggregated hybrid analysis is applicable for determining the total environmental inventory associated with the entire use of the functional unit or to compare two functional units. If no de-manufacturing stage is present, disaggregated hybrid should not be used. Suh [16] introduced a table where various LCI methods are compared. Table 1 is presented in its entirety with the disaggregated method added. Data requirements for each environmental inventory compilation method depend on practitioner’s goals. Hybrids by definition require commodity and environmental flows per sector and per process. Amount of data required by each hybrid varies, but general sources of data are similar. Disaggregated hybrid methods can obtain augmented data from current sectors to satisfy information needed for de-manufacturing process. However, in the future separate sectors for de-manufacturing should be calculated. The amount of uncertainty of data sources in hybrids depends upon shares of IO vs. process data. The uncertainty can be reduced by addition of


Table 1

915

Comparative characteristics of LCI methodologies (based on Suh [16]). LCI based on PA Process flow Matrix diagram representation

Hybrid LCI Tiered hybrid IO-based Integrated analysis hybrid analysis hybrid analysis Commodity Commodity Commodity Commodity Commodity Commodity and and and and and and Data environmental environmental environmental environmental environmental environmental requirements flows per flows per flows per flows per flows per flows per process sector and sector and sector and sector process process process process Uncertainty of Medium to Low Low Dependent* Dependent* Low source data high Upstream Medium to system Medium to poor Complete Complete Complete Complete poor boundary Technological Medium to system Complete Complete Dependent* Dependent* Complete poor boundary Geographical Domestic Domestic system Not limited Not limited Dependent* Not limited activities only activities only boundary Life use and end-of-life Poor Poor Medium Dependent* Dependent* Medium boundary Applicable Rare Abundant Rare Rare Abundant Abundant system tools Low, if Time and labor environmental Dependent* Dependent* High High High intensity data are available Simplicity of Simple Simple Simple Simple Complex Complex application Required Spreadsheet Matrix Spreadsheet Spreadsheet Matrix Matrix computational application inversion application application inversion inversion tools Most available Available MIET, MIET & LCA LCA software CMLCA CMLCA software tools EIOLCA software tools tools * Depends upon the shares of process analysis and IO-based system; ** This is a temporary constraint. IO based LCI

interactions between the two. Disaggregated hybrid allows adding interactions in order to create low uncertainty. However, interactions may significantly complicate the analysis. Without interactions disaggregated hybrid will have higher uncertainty level than integrated hybrid, but still lower uncertainty than tiered and IO hybrids because it includes more detailed de-manufacturing data. Upstream boundary conditions are complete for all hybrids, since all hybrids may include all post-manufacturing stages of life cycle analysis. Technological boundary conditions in the disaggregated hybrid depend on whether interactions between PA and IO components are

Disaggregated hybrid analysis Commodity and environmental flows per sector and process Low to medium* Complete Good* complete

to

Dependent* (but may be not limited) Nearly complete Not available** High Complex Matrix inversion Not available**

included and how much of PA data is available. The disaggregated hybrid’s technological boundaries are at least as good as tiered and IO-based hybrids in some cases, and better in cases where closed loop recycling is part of the analysis. Geographical system boundaries in the disaggregated hybrid depend on applications. If hybrid uses large amounts of IO data, some international data may not be available. Theoretically, it is possible to have unlimited geographic boundaries in any hybrid analysis. Life use and end-of-life boundary include de-manufacturing in the disaggregated hybrid method. Addition of this stage makes it more complete than

916


any other hybrid. Time and complexity of the analysis increase with amount of the data that must be processed. Disaggregated hybrid may be almost as simple as tiered hybrid or more complicated than integrated hybrid, depending on the practitioner. The more complete and accurate the data are, the more complicated the analysis of the time consuming is. System tools (IO databases) for disaggregated hybrid analysis are similar to the ones used for other hybrids and non-hybrids. However, there is no database developed for de-manufacturing stage. Since this paper is proposing disaggregated hybrid, it will take years before software and new database are developed. These are future projects that may be worked on after the publication of the new methodology and its thorough review by the scientific community. So far, no software is specifically developed for the disaggregated hybrid. The advantages of a disaggregated hybrid methodology are mainly related to inclusion of data from the de-manufacturing process and reduction in incompleteness of analysis. They are:  Reduced allocation between manufacturing and de-manufacturing processes simplifies complex calculations, reduces errors and improves ISO compliance;  Enhanced collaboration between manufacturer and de-manufacturer is encouraged when this method is used. Such collaboration may help to apply the holistic approach to optimization of environmental inventory of the functional unit (as opposed to a set of local optimizations on manufacturing and de-manufacturing sides);  Reduction in double-counting and truncation errors, compared to an analysis that treats manufacturing and de-manufacturing components separately or as separate processes;  Improved and better clarified boundary conditions of the LCI improve ISO compliance. The main disadvantages of the disaggregated hybrid methodology are associated with costs and difficulties

of the method. They are:  The proposed method requires an exchange of proprietary information between the manufacturer and de-manufacturer (this may not be the case if the manufacturer is responsible for treatment of its own products at the end of their useful life);  The data collection process on the de-manufacturing stage is difficult since the manufactured product may not have yet completed its lifecycle and, therefore, have not arrived to the de-manufacturing stage. Then, the de-manufacturing data for the similar (earlier versions) product may be used and adjusted by factor t, as described earlier. In addition, any change to the design of the product may be used to estimate changes in de-manufacturing inventory compilations. Such estimates bring in errors due to timing of de-manufacturing and changes in product design. However, for many commodity products and mature market products de-manufacturing data may be reasonably accurate. For new market products, however, such approach may introduce a large degree of error, comparable with error due to use of IO data. Process is more time and cost consuming, compared to other hybrid methods (it may not be more time consuming than integrated hybrid, depending on application). At the present time, no computer software is designed to account for disaggregated hybrid method analysis. The disaggregated hybrid method, similar to other LCA methods, may be prone to errors based on inputted data. Actual impact of errors is yet to be determined, based on the practical examples. From the theoretical standpoint, the disaggregated hybrid method is more accurate than the tiered hybrid method, more accurate than the IO-based hybrid method and very different from the integrated method to judge the accuracy the integrated hybrid has only been first introduced by Suh [16] less than seven years ago, and few studies regarding errors are published.


The disaggregated hybrid method aligns with the requirements of ISO as well as/or better than the existing LCA methods. The method is applicable and useful when the data resources are available and a detailed study is needed to optimize the environmental inventory of the functional unit.

References [1]

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[3] [4]

[5]

[6]

[7]

[8]

[9] [10] [11]

[12]

[13]

P.O. Busch, H. Jorgens, International patterns of environmental policy change and convergence, European Environment 15 (2) (2005) 80-101. M. Betsill, M.J. Hoffmann, The contours of cap and trade: The evolution of emissions trading systems for greenhouse gases, Review of Policy Research 28 (1) (2011) 83-106. S. Suh, Methods for life cycle inventory of a product, J. of Cleaner Production 13 (2005) 687-697. R.W. Parker, R.H. Tyedmers, Life cycle environmental impacts of three products derived from wild-caught antarctic krill (euphausiasuperba), Environ. Sci. Technol. 46 (9) (2012) 4958-4965. P. Zhai, E.D. Williams, Dynamic hybrid life cycle assessment of energy and carbon of multicrystalline silicon photovoltaic systems, Environ. Sci. Technol. 44 (20) (2010) 7950-7955. S. Nakamura,E. Yamasue, Hybrid LCA of a design for disassembly technology: Active disassembling fasteners of hydrogen storage alloys for home appliances, Environ. Sci. Technol. 44 (12) (2010) 4402-4408. S. Joshi, Product environmental life-cycle assessment using input-output techniques, J. of Ind. Ecol. 3 (2000) 95-120. M. Bilec, Example of hybrid life-cycle assessment of construction processes, J. of Infrastructure Sys. 12 (4) (2006) 207-215. S.P. Viera, A. Horvath, Assessing of end-of-life of buildings, Environ. Sci. Technol. 42 (2008) 4663-4669. T. Wiedmann, A Definition of Carbon Footprint, Technical report for ISA, New York, Oct. 2007. J. Munksgaard, K.A. Pedersen, M. Wier, Impact of household consumption on CO2 emissions, Energy Econ. 22 (2000) 423-440. B.W. Ang, G. Pandiyan, Decomposition of energy-induced CO2 emissions in manufacturing, Energy Econ. 19 (1997) 363-374. Y.F. Chang, Structural decomposition of industrial CO2

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[17]

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emission in Taiwan: An input-output approach, Energy Pol. 26 (1998) 5-12. R. Heijungs, S. Suh, The Computational Structure of Life Cycle Assessment, Kluwer Academic Publishers, Dordrecht, Netherlands, 2002. T. Marheineke, R. Friedrich, W. Krewitt, Application of a Hybrid Approach to the Life Cycle Inventory Analysis of a Freight Transport Task, SAE Tech. Paper Series 982201, Atlanta, 1998. S. Suh, System boundary selection in life-cycle inventories using hybrid approaches, Env. Sci. and Tech. 38 (3) (2004) 657-664. Y. Moriguchi, Y. Kondo, H. Shimizu, Analyzing the life cycle impact of cars: The case of CO2, Ind. and Env. 16 (1) (1993) 42-45. H. Hondo, K. Nishimura, Y. Uchiyama, Energy Requirements and CO2 Emissions in Production of Goods and Services: Applications of the Input-Output Table to Life Cycle Analysis, Technical report for Central Research Institute of Electric Power Industry, Tokyo, Japan, 1996. S. Suh, G. Huppes, Techniques of life cycle inventory of a product, Ph.D. Thesis, University of Leiden, Netherlands, 2002. J.B. Guinee, M. Gorree, R. Heijungs, G. Huppes, R. Kleijn, L. Wegener Sleeswick, et al., Handbook on Life Cycle Assessment: Operational Guide to the ISO Standards, Kluwer Academic Publisher, Dorchester, Netherlands, 2002. S. Suh, Functions, commodities and environmental impact in an ecological-economic model, Ecol. Econ. 48 (2004) 451-467. R. Heijungs, Reformulation of matrix-based LCI: From product balance to process balance, J. of Cleaner Prod. 23 (1) (2006) 47-51. R.T. Hunt, L. Boguski, K. Weitz, A. Sharma, Case studies examining LCA streamlining techniques, International Journal of Life Cycle Assessment 3 (1) (1998) 452-461. M. Lenzen, Errors in conventional and input-output-based life-cycle inventories, J. of Ind. Ecol. 4 (4) (2000) 127-148. G. Huppes, F. Schneider, Proceedings of the European Workshop on Allcation in LCA, Feb. 24-25, 1994, Leiden. R.H. Crawford, Greenhouse gas emissions embodied in reinforced concrete and timber railway sleepers, Environ. Sci. Technol. 43 (2009) 3885-3890.


D

DAVID

PUBLISHING

Assessment of Soil Erosion in Mountain Watershed Ecosystems in Tirana-Region Entela Çobani and Oltion Marko Department of Environmental Engineering, Faculty of Civil Engineering, Polytechnic University of Tirana, Tirana 355, Albania Received: May 21, 2012 / Accepted: June 5, 2012 / Published: July 20, 2012. Abstract: Land erosion is an increasing problem that is seriously affecting our country in recent years. In many areas of our country, mountainous and hilly territories suffer major erosion in both surface and depth, where the solids are deposited in the flat parts of the country, thus leading to a higher content of gravel in agricultural land and filling of the sewage networks. The phenomenon of erosion is greater in the vicinity of residential areas where damages are larger and more sensitive. One of the most vulnerable in our country in terms of soil erosion is the district of Tirana. This study had the main goal to define and categorise of erosion rates in natural environments of the forest economies of the Tirana, the rate of recovery of vegetation, slope and rainfall index, which will serve as information and guidance on the land use by farmers, communes and the state regulatory officials, depending on the ownership of these woodland surfaces. Key words: Erosion, ecosystem, soil, slope, land cover, vegetation.

1. Introduction Soil erosion represents one of the most destructive phenomena of the earth, by both surface and depth erosion. The relatively significant activity of water erosion that is observed in our country is favoured by many factors such as landscape, geological structure, slope, soil, climate, etc.. The increased intensity of erosion is closely linked with high rate of destruction of vegetation cover. The degradation of vegetation or its complete destruction is determined by many factors, especially by the socio-economic system of each country [1]. This is also observed in Tirana, where as a result of negative impacts caused by mankind on the natural environment, the erosion phenomenon is becoming more and more problematic, especially during periods of intense precipitation. This phenomenon is also significantly affecting on massive slides which are already evident in many areas of the country, causing considerable damage to the Corresponding author: Oltion Marko, Ph.D., research fields: soil erosion, forest, waste treatment technology, environment. E-mail: [email protected].

environment, and in the economy. A crucial role in preventing this phenomenon belongs to vegetation, especially the forest [2]. But the role of vegetation is not immediately seen after its installation.

2. Materials and Methods Tirana area is one of the most typical areas of our country regarding the development of erosion. The study and analyzing of the factors that influence the development of erosion is based on a methodology which is used to assess the risk of erosion also in other areas of our country, where data are collected according to the division of forest economies [2]. Regarding the separation of the vegetation coverage rate, it is done according to this grouping: up to 0.3; 0.4-0.7 and > 0.70 [3, 4]. Assessment of the risk of erosion as per the slope is grouped as follows: 0°-5°: little risk of erosion; 6°-15°: moderated risk of erosion; 16°-30°: average risk of erosion; 31°-45°: major risk of erosion;

Assessment of Soil Erosion in Mountain Watershed Ecosystems in Tirana-Region

> 45°: strong risk of erosion. Soil erosion rate is determined by comparing the open profile of land with the standard profile in terms of soil erosion at four levels as follows [5]: Class 1: up to 25% of a horizon in most of the surface; Class 2: from 25%-75% of a horizon in most of the surface; Class 3: over 75% of the horizon and generally also a part of B horizon; Class 4: deeply eroded soil, in such a way which presents a network streams with average depth or deep depth. To express the degree of aggressiveness of the climate factor, the combination of the product of the amount of multi-annual mean precipitation with the sum of precipitation during the critical period, for each 100 m elevation above sea level is used, according to Eq. (1) [6]: R  Rk (1) Ir  v 10 . 000 Ir—rainfall indicator; Rv—sum of multi-annual mean rainfall in mm; Rk—sum of multi-annual mean rainfall during the critical period in mm; 10.000—coefficient of converting the results into reduced productive values. From the literature indicator Ir (indicator of rainfall) is classified as follows: Ir < 50: erosion risk of first category; 51 ≤ Ir ≤ 80: erosion risk of second category; 81 ≤ Ir ≤ 150: erosion risk of third category; 151 ≤ Ir ≤ 275: erosion risk of fourth category; Ir > 275: erosion risk of fifth category.

3. Results and Discussion The total area of forest economies (the studied area) is 83.840 ha, divided according to the forest economies and the vegetation coverage rate which is as follows: As it can be seen from the data in Table 1, most of the forest area of Tirana district take part in the interval of 0.3 with 55%, then in the range of 0.4-0.7 with 27.5% and in the interval of 0.7 with 17.5%.

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Table 1 Forest area according to coverage rate. Up to 0.3 44,501.8

Area according to coverage rate (ha) 0.4-0.7 > 0.7 26,974.25 12,363.95

This shows that the forest vegetation in these economies is deteriorated, which directly affects the dynamics and development of soil erosion. Field study of soil is made on the basis of expeditions carried on during the period of 2003-2006, and ongoing consultation with studies previously conducted in these economies. For each main profile considered in the field, the relevant files were completed and for each horizon the morphological description was done where samples were taken from 500-1,000 g which were labelled and restudied in a subsequent stage. From the analysis made in this area it resulted to have these land types and subtypes: (1) Brown mountain lands which lie in the belt of oak forests ranging from 400 m to 1,400 m above sea level in height. This type of land is located in the form of two subtypes, according to the FAO classification Eutric Cambisols (CMe) and Rhochic Nitosol (NTr); (2) Fulvous forest lands which lie on land formations above the area mountain brown lands, at the height ranging of 1,200-1,800 m above the sea level. This type of land is found in the form of two subtypes, Humic Camisols (CMu Humic Nitosols (NTu)); (3) Brown meadows lands, or Haplic Phaeazems (CME). The slope gradient is one of the main elements of landscape that has an impact on soil erosion. Given the fact that in this area the vegetation is degraded, the influence of inclination of the slopes will be greater. According to the management plans and inventories of forest economies and topographic maps, the categorization of slope was done as follows: As seen from Table 2, the slope of the mountain in this area is from moderate to large. Soil erosion rate is determined by comparing the considered profile with the standard one, and in terms of soil erosion it is

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Table 2 The area according to the slope. 0°-5° 4,104

Area (ha) according to the slope 6°-15° 16°-30° 31°-45° 4,117 66,761 8,364

> 45° 494

classified in four classes: Class 1 (E1): Up to 25% of the first horizon (A) in most of the surface; Class 2 (E2): From 25%-75% of the first horizon (A) in most of the surface; Class 3 (E3): Over 75% of the first horizon, and generally, part of the horizon (B); Class 4 (E4): Deeply eroded soil. In a more detailed way, the erosion rate is presented in Table 3. As seen from Table 3, erosion in forested areas of Tirana district is quite large, where around 41% of the surface area takes part in the third and fourth grades of erosion. Erosion by the vegetation coverage rate is made after determining the classes of coverage of forest vegetation, where by the surfaces with coverage rate (0.1-0.3, 0.4-0.7 and > 0.7), profiles were opened, in the same way as for determining the degree of erosion. In Table 4, it presents the distribution of erosion risk classes in function of the degree of coverage by

vegetation. As seen from Table 1, surfaces with coverage of 0.1-0.3 are the most affected by erosion, as a result of degradation of vegetation, while in areas with large scale of coverage (> 0.7) no erosion of class E4 is found. Table 5 presents the distribution of erosion risk classes according to the slope which characterize the area, where grouping according to the slope is done at five levels (0°-5°, 6°-15°, 16°-30°, 31°-45°, > 45°). As seen from Table 5, the surface with small scale slope (0°-5°), no erosion of fourth class is found, while in areas of steep slope (> 45°), only erosion of third and fourth classes is found. This shows the influence of slope in the development of soil erosion process. While erosion under rainfall index is done by calculating the average annual rainfall for 100 m above sea level, and the critical period is October-March. Results for this indicator are given in Table 6. Regarding the precipitation indicator, territories up to 100 m above sea level are classified in the first category, by 200-500 in the second category, by 600-1,100 in the third category, by 1,200-1,700 in the fourth category and for altitudes > 1,700 m above sea level in the fifth category.

Table 3 Rate of erosion. Rate of erosion E1 ha 19,441

E2 % 23

ha 29,808

E3 % 36

ha 18,646

E4 % 22

ha 12,945

% 19

Table 4 Determination of the erosion rate according to the coverage rate. Class E1 E2 E3 E4

0.1-0.3 2,745.60 13,633.55 18,703.80 9,418.85

Area in (ha) divided according to coverage rate 0.4-0.7 > 0.7 7,467.6 9,228.25 13,935.9 2,238.80 2,044.95 896.90 3,525.80 -

Total (ha) 19,441.45 29,808.25 21,645.65 12,944.65

Table 5 Determination of the erosion rate according to the slope. Class E1 E2 E3 E4

0°-5° 3,115.3 824.4 164.9

6°-15° 1,438.1 2,058.9 494.1 126.5

Area in (ha) divided according to the slope 16°-30° 31°-45° 14,181.8 706.2 25,159.4 1,765.5 18,411.1 2,471.7 9,009.1 3,420.8

> 45° 103.8 389.2

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According to the classification made by grouping

Table 6 Calculation of rainfall indicator. Altitude above sea level (m) 100 200 300 400 500 600 700 800 900 1,000 1,100 1,200 1,300 1,400 1,500 1,600 1,700 1,800 1,900 2,000

Rainfall indicator Ir 86.4 99.3 113.0 127.5 143.0 159.3 176.8 195.0 214.1 234.0 254.8 276.4 299.5 322.5 347.7 373.0 398.7 426.2 454.1 483.0

Erosion risk category I II II II II III III III III III III IV IV IV IV IV IV V V V

4. Conclusion From the study and analysis of search results, it will arrive at some preliminary conclusions of the study: The study area lies on three land types. Brown mountain lands lie in the belt of oak forests ranging from 400 m above sea level to 1,400 m. This type of

classes of erosion according to vegetation cover rates, it shows that the surfaces of small scale coverage have more erosion of third and fourth class. Based on the results of rainfall indices the erosion risk is distributed in five categories, from I to V. In areas that are eroded and that present the risk of slippage or landslips it should be intervened by biological works, where these works should be made on those surfaces which have degraded vegetation. In the upper parts of water catchment areas, where the amount of liquid and solid flow is less, protective fences with wood material must be constructed, as well as dikes with dry stone masonry with concrete. In risk areas risk of slippage or landslips, hydro-technical works should be built with gabions, as they are more flexible. In the main bed flow hydro-technical works must be constructed

The current rate of erosion turns out to be quite critical. It is divided into four classes: first class includes 19,441.45 (ha) or 23% of the total area, the second class 29,808.25 (ha) or 36%, the third class 18,645.65 (ha) or 22% and the fourth class 12,944.65 (ha) or 19%.

.

mortar

stone

walls

account the permeability of the terrain to be placed.

References [1] [2]

[3]

effects on the forest environment from anthropogenic factors seem to be quite large.

cement

dimensioned according to given methods, taking into

land is located in the form of two subtypes. The study of vegetation shows that interventions with negative

with

[4] [5] [6]

O. Marko, Land Erosion and Measures of Restoration, SHPLU Tirana, Tirana, 2010, pp. 10-35. O. Marko, Risk evaluation of masive forests erosion in Vithkuqi area district of Korca, Ph.D. Thesis, Agriculture University of Tirana, Tirana, 2006. D.B.C. Beasley, L.F. Huggins, E.J. Monke, ANSWERS: A model for watershed planning, Transactions of ASAE 23 (1980) 938-944. Management of Land Cover in Watershed, FAO, Italy, 1977, pp. 55-80. O. Marko, Assessment of Soil Erosion Risk in Mountains Watershed, DDS Tirana, Tirana, 2010, pp. 94-100. H.M.J. Arnoldus, An approximation of rainfall factor in the universal soil loss equation, in: M. De Boodt, D. Gabriels (Eds.), Assessment of Erosion, Record No. 19831974087, 1980, pp. 115-170.


D

DAVID

PUBLISHING

The Impact of the Ghana’s Oil Discovery on Land Investment and Its Implications in the People, Agriculture and the Environment (Case Study: Cape Three Points, Ghana) Peter Paa-Kofi Yalley1, Chris Atanga2, Joe Fredrick Cobbinah3 and Philip Kwaw4 1. Design and Technology Department, University of Education, Kumasi 233 32, Ghana 2. Western Regional Land Commission, Sekondi 233 31, Ghana 3. Building Technology Department, Takoradi Polytechnic, Takoradi 233 31, Ghana 4. Civil Engineering Department, Takoradi Polytechnic, Takoradi 233 31, Ghana Received: January 11, 2012 / Accepted: March 10, 2012 / Published: July 20, 2012. Abstract: The study was conducted to assess the impact of Ghana’s oil discovery on the land values, the extent of acquisition, and their implications of the land investment in the people, agriculture and the environment in the Cape Three Points area, which is the communities close to the oil field. Questionnaires were designed and administered to collect data from the chiefs, queen mothers, family heads and opinion leaders of the area. Results of the studies indicated that there had been an increase of about 2000% in land values from 2007 to 2011. Also there was an increase in demand for lands in the Cape Three Points with acquisitions usually ranging from 10 acres to over 600 acres. It also emerged that the livelihood of the inhabitants of Cape Three Points was threatened due to the conversion of arable land to non-agriculture uses. This change in land uses has significant negative impacts on land degradation and its related reduction of agricultural and food production in the area. The technical difficulties of assessing land degradation, the weakness of existing databases, and the poorly explored linkages between land degradation and other aspects of rural development were some of the limitation of the studies. The study increased awareness of the chiefs and other land owners to reserve land for the future generation and for agriculture purposes. The study drew government’s attention through the Ahanta West District Assembly to the planning needs of the towns in the Cape Three Points to streamline land use of the area. Key words: Cape Three Points, oil, agriculture, land, degradation.

1. Introduction On June 18, 2007 a consortium of oil companies—Kosmos, Tullow, Anadarko Petroleum, Sabre Oil and Gas in conjunction with GNPC (Ghana National Petrolum Cooperation) announced the discovery of oil and gas accumulation in the territorial waters of Ghana 33 miles off the shores to the West of Cape Three Points in the Ahanta West District of the Corresponding author: Peter Paa-Kofi Yalley, Ph.D., lecturer, main research fields: innovative materials, land, housing and environmental science. E-mail: [email protected], [email protected].

Western Region, Ghana [1]. Though the oil and gas accumulations are discovered miles into the sea, there exists an intractable link between the discovery and land investment in the area. Primarily the government, corporate bodies and individuals would require land in these areas for various activities. These investments would generally be classified under residential, commercial, industrial as well as other uses. Since proximity has become a crucial issue in these investments, towns within the immediate environs and the catchments area in general have become the focal point of most land investors.

The Impact of the Ghana’s Oil Discovery on Land Investment and Its Implications in the People, Agriculture and the Environment (Case Study: Cape Three Points, Ghana)

For instance, Ref. [2] reports of a massive rush for lands at Cape Three Points Area by speculators, private individuals and cooperate bodies. Hence towns like Attenkyen, Akwidaa, Butre, Egyambra, Princess Town, Axim, Half Assini etc. which fall within the immediate environs of the oil field have suddenly become places of interest for land investors. Unfortunately, most of these towns are not well developed and are without proper planning schemes or land use plans and even where planning schemes exist they are not appropriate to cater for the current land requirements. Drilling of the oil will have a very great impact on land activities, notwithstanding the fact that the oil drilling is a way into the sea. The desire for individuals and corporate bodies to own land in these areas is inevitable. Hence, the need for proper planning of towns can not be over emphasized. Where towns are left to develop on their own without any proper planning, major disasters such as flooding, fire outbreaks, diseases etc., are always imminent. The purpose of this research was to investigate into:  the nature and extent of land investment;  the impact of the land investment on the socio-economic life people of Cape Three Points;  the implication of change in land use on agriculture and the environment;  the current planning schemes of the area;  drawing government’s attention to the planning needs of the towns in the Cape Three Points Area. This

was

done

through

interviews

and

questionnaires with chiefs, family heads and members of the communities where the research was conducted. 1.1 Background of the Study Area Ghana, which lies in the center of the West African coast, shares borders with the three French-speaking nations of Côte d'Ivoire to the west, Togo to the east, and Burkina Faso (Burkina, formerly Upper Volta) to the north. To the south are the Gulf of Guinea (Fig. 1). With a total area of 238,533 square kilometers, Ghana

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is about the size of Britain. Its southernmost coast at Cape Three Points is 4°30’ north of the equator. From here, the country extends inland for some 670 kilometers to about 11° north. The distance across the widest part, between longitude 1°12’ east and longitude 3°15’ west, measures about 560 kilometers. The Greenwich Meridian, which passes through London, also traverses the eastern part of Ghana at Tema. Ghana is characterized in general by low physical relief. Indeed, the Precambrian rock system that underlies most of the nation has been worn down by erosion almost to a plain. The highest elevation in Ghana, Mount Afadjato in the Akwapim-Togo Ranges, rises only 880 meters above the sea level. There are, nonetheless, five distinct geographical regions which are: Low plains stretch across the southern part of the country, the Ashanti Uplands, the Akuapim-Togo Ranges, the Volta Basin and the high plains which occupies the northern and north-western sector of the country. Like most West African countries, Ghana has no natural harbors. Because strong surf pounds the shoreline, two artificial harbors were built at Takoradi and Tema (the latter completed in 1961) to accommodate Ghana’s shipping needs. Cape Three Points refers to the three major capes being the southernmost part of the country and serves as a major landmark for navigation. Some of the towns around this area are Akwida, Attenkyen, Aketekyi, Prince’s Town and Egyambra which are linearly located along the South-Western Coastal Belts of the country. Beside these three major capes are several other minor capes spanning along the coasts of these towns which portray a beautiful coastal belt. The name Cape Three Points has been narrowed down to one particular town locally known as Attenkyen. During the research it is found out that there is another town in the area known as Katakow which is about one kilometre away from Attenkyen. In this study any reference to Cape Three Points is limited to these two towns, namely, Attenkyen and Katakow. Another important feature in Cape Three

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Fig. 1 Map of Ghana.

Points is the forest reserve which was declared a forest reserve in 1949 and is the only primary forest in Ghana that is close to the sea and recognized for its biodiversity. No education facilities is above junior high school. Cape Three Points has no basic facilities such as electricity, telephone and potable drinking water. Agricultural is the main activities engaged in by the people. A larger section of the populace is also engaged in small scale fishing. The tourism potentials of the towns can be viewed from both aesthetic and historical points of view. Aesthetically, these towns can boast of very beautiful sandy beaches and are classified among the finest beaches in Ghana stretching from Butre, through Busua, Akwidaa, Cape Three Points, Egyambra, Princess Town to Axim. Very popular among these beaches are the Busua Beach Resort, Miamia Beach Resort, Akwidaa Beach, Axim Beach and Ankobra Beach. Beaches in the Cape Three Points area are signified by a variety of capes, three among which are very outstanding. The Ghana Port and Harbours Athourity (GPHA) lighthouse (Fig. 2) which provides direction to vessels navigating through that point stands on the West Cape which happens to be the deepest among the capes. Egyambra which is close to Cape Three Points is also

known for its crocodile pond, where these crocodiles are quite distinct because of their good taste for Coca Cola drink. Some of the historical sites are the Fort St. Antonio at Axim, Fort Friederichsberg located at Princess Town, and Fort Appollonio at Beyin (Fig. 3). Despite all the potentials, there is no meaningful planning of developments in Cape Three Points and its neighbouring towns. There are no proper market facilities, lorry parks etc.. The buildings do not conform to any development pattern as residential and commercial activities can not be differentiated. The settlements are very compact and allow no means for vehicular movement hence, vehicular movement within the towns are impeded by the haphazard location of structures. 1.2 Environmental Damage in Oil and Gas Producing Countries The exploration and production of oil and gas in any country is followed with many environmental challenges. The environmental problems begin when the start of seismic survey through exploration and continue to the end of the operation and abandonment. Seismic survey could lead to acoustic emission and accidental spills of chemicals that pollute the sea;


Fig. 2

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GPHA lighthouse at Cape Three Points.

Beaches at Cape Three Points

Fort Saint Antonio at Axim.

Fig. 3

Appollonio at Beyin

Beaches and fort at Cape Three Points.

exploratory activities which could cause drilling discharges, atmospheric emissions and spills lead to marine and air pollution affecting fishing. Development and production of oil cause operational discharges, atmospheric emissions, waste disposal and noise, leading to ground and marine pollution. Whenever oil field is abandoned, it is always accompanied with the removal of structures, waste disposal and dumping at sea leading to endangered

fishing and navigation [3]. Oil spills in the petroleum industry in particular have been a major concern because of recorded incidents like the Amoco Cadiz (1978), which spilled 220,000 tons of oil; the Exxon Valdez (1989), spilling 40,000 tons of oil and the Braer (1993), spilling 85,000 tons of oil [4]. These oil spills caused ecological disasters affecting fish, birds, and mammals [4].

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2. Research Methods

institutions.

To investigate the impact of the oil discovery on land investments, its implication in socio-economic activities of the people, agriculture and the environment of Cape Three Points, primary data was gathered through two rounds of questionnaire surveys and face-to-face discussions. In order to evaluate the clarity and how respondents were going to answer the questions, a pilot survey was conducted before the first round of the survey. Out of the 35 distributed questionnaires in the first round of survey, 26 valid responses were received, representing a response rate of 74.3%. The second round of survey was conducted and was extended to Princes Town and Egyambra in the same region two years later in order to check the results of the first round survey. Thirty four respondents were involved in the second survey. Again, respondents were required to have basic knowledge about land acquisition in the case study area. Face-to-face discussion was emphasized in this survey; the results are mirrored in the discussion later. The outcome confirmed the results from the first survey. The questionnaire had four sets of questions: (1) Respondent characteristics: Demographics on the respondent’s professional background and organization; (2) Land demand and values: This set of questions intended to compare the price and demand of land before and after the announcement of oil discovery in the Cape Three Points area; (3) Land use and planning schemes of the area: Intended to find out if there had been changes in the land-use pattern after the announcement of oil discovery in the Cape Three Points area. And also to find out if there was a planning scheme in the Cape Three Points area; (4) Conflicts associated with land delivery in the Cape Three Points area: The researchers wanted to find out if the sales of land had generated any conflict. Structured interviews were also used to obtain information from some heads of the relevant public

3. Results This section analyzes the data collected during the research through the administration of the questionnaire and interviews. 3.1 Demography of Respondents The respondents were made up of six traditional rulers, three queen mothers, two assemblymen and 13 family heads. In all 26 questionnaires representing 74% were received out of 35 questionnaires which were sent out. All the respondents including the chiefs were subsistence farmers with the exception of two assemblymen who were trained teachers. Thirty four respondents were involved in the second survey. They represented: government officers (6%), chiefs (19%), family heads (21%), investors (31%) and opinion leaders from the communities (23%). 3.2 Land Investment in Cape Three Points A check on land documents received from Refs. [5, 6] from these areas and investigations conducted in these towns showed that land acquisitions in the Cape Three Points area had increased significantly after the announcement of the oil discovery. The research revealed that large tracts of lands had been sold out to people after the announcement of the oil discovery. Data from Refs. [5, 6] as indicated in Table 1 show that between June 2006 and May 2007, only 27 documents were received by the Lands Commission for processing from the Cape Three Points. Out of this number, 52% were for residential purposes, 26% for beach resorts, 15% for agricultural purposes and the remaining 7% for other uses. It could be seen from Table 1 that out of the 27 land documents processed the size for residential purposes was less than one acre. That for beach resorts was between 1 and 10 acres and that for agricultural purposes was above 10 acres with a maximum acreage of 49.7. However, between June 2007 (after the announcement of oil discovery)

The Impact of the Ghana’s Oil Discovery on Land Investment and Its Implications in the People, Agriculture and the Environment (Case Study: Cape Three Points, Ghana) Table 1

Statistics of land documents received by Lands Commission, Sekondi, Ghana a year after oil discovery.

Purpose Doc. received %

Res. 14 52

Average Acreage, x

x≤1

Before oil found (2007) Agric Resort Indust. 4 7 2 15 26 7 1≤x≤ 1≤x≤ 1 ≤ x ≤ 10 10 10

and May 2008 a total of 53 documents were received by the Lands Commission for processing. This was almost a 100% increase in the documents received by the Lands Commission over the previous year. Out of this number, 57% were for residential purposes, 30% for beach resorts and recreational purposes, industrial 11% and commercial 2%. Among these documents received, the trends of the sizes were the same as before the announcement of the oil discovery, except that the maximum acreage for lands for industrial and commercial purposes was 600. Table 2 shows that from the year from 2002 to 2006 the average yearly incremental rate in land values at the Cape Three Table 2 Year 2002 2003 2004 2005 2006 2007 2008 2009 2011

Total 27 100

Res. 30 57 x ≤ 1

Comm. 1 2 10 ≤ x ≤ 600

After oil found (2008) Resort Indust. 16 6 30 11 1 ≤ x ≤ 10 ≤ x ≤ 10 600

Total 53 100

Points was about 23%. However, after the announcement of the oil discovery in 2007, the trend changed suddenly and by the year of 2008 the values of an acre of land in the Cape Three Points was about GH¢4,000.00 which was an increase of about 700% over the value of land before the announcement of oil discovery. A recent visit to the area (second survey) revealed that the current value of an acre of land in the Cape Three Points was about GH¢15,000.00. This then implies that between 2007 and 2011 an increase in land value in the Cape Three Point was about 2,000%. From Fig. 4, there is a sudden sharp increase in

Land values in the Cape Three Points since 2002. Land values per acre 100 120 150 200 300 500 4,000 9,000 5,000

Yearly increase (%) 0 20 25 30 50 67 700 125 67

Accumulative increase in land values (%) 0 20 45 75 125 195 892 1,017 1,084

Land Values at Cape Three Points

Fig. 4

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Graphical presentation of land values in the Cape Three Points area since 2002.

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the gradient of the curve after 2006. The slope became steeper after 2008. This behaviour of the curve clearly interprets the sudden increase in the land demand and value in the case study area after the announcement of the oil discovery in 2007. 3.3 Land Use Requirements and Planning Scheme In investigating the land-use requirement in the Cape Three Point, it was revealed that land-use requirement for agricultural purposes had given way to new uses such as industrial, commercial, hotel, beach etc.. A report from Ref. [7] indicates that Cape Three Points and Egyambra Townships had no planning scheme and only about a quarter of Princess town had planning scheme dating back to 1998, of which the land was mostly schemed for agriculture and residential. The researchers noticed that no policy decision had been taken yet to curb the growing trend in land demand for the area, although the Town and Country Planning Department of the Ahanta West District was embarking on a Programme on the Land Use by Management in the District at the time of the research. According to the chiefs, the Lands Commission together with the Survey Department undertook a duty tour of the Cape Three Points to familiarise themselves with the area and it was their hope that planning of the area would soon begin. 3.4 Conflicts Associated with Land Delivery in the Cape Three Points Area The sudden upsurge of the land demand in the Cape Three Points has awakened the interest of a lot of claimants to land in the area. The family heads and the chiefs interviewed agreed with the records from the Regional Lands Commission office, Sekondi, which over 30 new families have emerged since the oil discovery announcement. This has resulted in conflicting claims. At the Cape Three Point, parcels of the same land were granted to different investors by the various claimants as was testified by some

investors. This has resulted in fierce dispute among the contending parties as well as the investors.

4. Discussion 4.1 Impact of the Oil Discovery on Land Investments in Cape Three Points Most towns in the Cape Three Points do not have planning schemes and in a larger context, there are no major land-use plans guiding land acquisitions in the area for the various uses yet the area happens to be the focus for land acquisition. After the announcement of the oil discovery, the current research revealed that there had been an increase in demand for parcels of land by investors and speculators for various uses mostly for non-agricultural uses. The reasons accounting for the sudden increased in demand for land in the study area were as following: (1) Proximity and Easy Accessibility to the Oil Drilling Site Major players in the oil field would like to take their positions in areas closer to the oil drilling in order to take advantage of proximity so as to save time and cost of transporting materials and workers to the drilling site. Secondly, goods can be transported directly from Takoradi Harbour to Cape Three Points. The area falls within the nation’s coastal belts. It is therefore easy for companies to have seaports to transport materials from the land to the drilling site. Institutions such as banks, real estate developers etc., would want to be closer to the oil sites to facilitate the provision of their services to oil and other companies. (2) Tourist Attraction The Cape Three Points also has a lot to offer in terms of tourism because of its beautiful beaches and historical sites. A lot of people from all walks of life would like to travel to the area, due to oil discovery and tourist attraction in the area. Hence the requirement for land for resorts, hotels and guest houses is very paramount. (3) Profit


Speculators would want to buy these lands at lower prices and resell them to future investors at higher prices. It appeared during this study that most of the people involved in the rush of land were speculators. This had compelled some investors to relocate to Agona Nkwanta the Ahanta West District Capital, where land values were relatively low. It was also noted during the research that most of the acquisitions had not been registered with Land Commission. This situation was attributed to following: multiple sales of the same parcel of land by the same stool/family; multiple grant of the same parcel of land by different stools/families, chieftaincy disputes, improper documentation, illegitimate right of lessors to dispose of these lands, stool-family conflict etc.. Since the area has become very important due to the oil found, it is more important for Land Commission to have records of all lands in the area. The problem of land registration could be resolved if a legislative instrument is enacted compelling the chiefs and family heads in the Cape Three Points to stop selling land. This can be effective if planning schemes are prepared to reflect the current land-use requirement. Stools and families claiming ownership of lands in these areas should also furnish the Lands Commission with their land boundaries to avoid land litigations. Where boundary conflict arises, the entire portion should be vested in the Government until the boundary dispute is resolved. This would ensure that development is not impeded by land litigation. Even though there is collaboration between the various Land Sector Agencies (Lands Commission, Town & Country Planning Department, The Survey Department and the Office of the Administrator of Stool Lands), these institutions have not yet adopted a single policy direction to forestall the consequences of the surge on land demand for the area. The faster rate of land acquisition in the Cape three Points without the required planning could have a negative impact on the socio-economic well-being of the people and the environment if not well managed.

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4.2 Implications of the Land Demand on the Socio-Economic Life of the People, Agriculture and the Environment of Cape Three Points The majority of the populace relies on agriculture for livelihoods. The conversion of arable land to non-agriculture uses threatens the livelihood of the inhabitants of Cape Three Points. This also has significant negative impacts on agricultural and food production in the case study area. The authors’ analysis suggests that declining food supplies from Cape three Point (due to land degradation or any other factor) will have only a modest effect on Ghana’s food supplies because of the potential for substitution from other producing areas. However, there could be quite dramatic effects on the people if no alternative source livelihoods are provided, especially in a situation where the people have not acquired the competency to work in the oil field. Since agriculture is the dominant sector in Cape Three Points, the lost of farm lands to other non-agriculture uses would increase the concentration of poverty: landless workers, small tenant farmers, and small farm owners. This would compel the farmers to cultivate smaller and smaller plots, where the soil eventually becomes depleted, or they may expand onto marginal lands-fragile hillsides, semi-arid areas, and cleared forestland. If this practice continues, there would be a major depletion of the forest reservation and woodlands in the area, with hazardous consequences on the ozone layer. Cape Three Points is also known as the virgin area due to its forest reserved. The influx of oil service industries and other nonfarm groups may also create externalities that contribute to farmland degradation through their use and management of natural resources. These may include urban sprawl, soil pollution from industry or waste management, diversion of local water sources to distant or non-agricultural users, road and infrastructure building practices that erode farm landscapes, and rules to protect biodiversity that restricts agricultural land use and management [8].

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The oil and gas exploration in Ghana is offshore. The nearest town to the operation area is Cape Three Points. There are however a number of towns along the coast of the Gulf of Guinea, where the exploration activity is taking place. Another major traditional occupation of the local people is fishing. The sea is therefore their source of economic sustenance. The production and development of the oil and gas itself is likely to generate various environmental problems. Firstly, there could be oil spill and leakages. The consequence is the emission of hydrocarbon elements into the sea destroying sea life. This will have a direct negative effect on the vocation of the local fishing people. Secondly, should there be gas flaring, excess gas will emit toxic chemicals into the atmosphere, causing health problems among workers and people in the locality.

5. Conclusion A research was conducted to investigate the impact of the oil discovery on the land investment in the close environ of the oil field and came out with the following conclusions: The exploration area is already under economic siege. Corporate institutions and businessmen have descended on the area in search of land, for various economic activities. Land, being a factor of production, is in high demand. The acquisition of land for housing and other commercial activities will directly increase the population of the area. The immediate consequence is the high migration of people to the area, leading to urbanisation with its numerous problems. As a result, there will be sanitation problems, crime wave and social disorder calling for secured facilities. The study increased awareness of the chiefs and land owners to reserve land for the future generation and for agriculture purposes. The people were strongly

advised to send their children to school so that they could take advantage of the opportunities due to the oil discovery in the area.

6. Recommendation The research therefore recommends that the Cape Three Points be declared a planning area. The Lands Commission can then rely on the planning scheme to process documents emanating from the area. Development control measures should be instituted to ensure that land uses are compatible with the planning schemes. The Ministry of Lands Forestry and Mines should be swift in acquiring lands in the area for land banks. This will make access to land easier for investors and save the cost and time involved in land acquisition.

References [1]

[2]

[3] [4]

[5] [6] [7]

[8]

Ghana National Petroleum Corporation, Discovery of Oil and Gas Accumulation in the Territorial Waters of Ghana, Ghanaian Daily Graphic report, Accra, June 18, 2007, pp. 1, 3. J.K. Adda, Massive Rush for Lands at Cape Three Points Area, Ghanaian Daily Graphic report, Accra, Mar. 8, 2008, pp. 1, 3. Z. Gao, Environmental regulation of oil and gas industry, CEPMLP Discussion Paper, DP16, 1997. S. Patin, Environmental Impact of the Offshore Oil and Gas Industry, SciTech Book News, Book News, Inc., USA, 1999. Land Title Records, Western Regional Land Commission, Sekondi, Ghana, 2010. Land Valuation Records, Regional Records, Western Regional Land Valuation Board, Sekondi, Ghana, 2009. District Records, Town and country planning report, Ahanta West District Assembly, Agona Nkwanta, Ghana, 2010. S.J. Scherr, S. Yadav, Land Degradation in the Developing World: Implications for Food agriculture, and the Environment, Status report, International Food Policy Research Institute report Washington, D.C. USA, May 1996.

D


DAVID

PUBLISHING

Influence of Rainfall, Discharge, Wave and Alongshore Transport on Microbiological Pollution in Southern California Coastal Beaches Seung Yeon Choi1 and Youngsul Jeong2 1. Fairmont Preparatory Academy, Anaheim 92801, CA, USA 2. Department of Natural Sciences, Washington Baptist University, Annandale 22003, VA, USA Received: June 11, 2012 / Accepted: June 18, 2012 / Published: July 20, 2012. Abstract: The coastal zone is the significant environmental setting where ocean interfaces land. In addition,I t is economically important because of its high residential, commercial and recreational values. Meanwhile, in the United States, public coastal areas are increasingly off-limits due to elevated levels of fecal pollution and other contaminants. This study investigates the effects of rainfall, discharge, wave, and alongshore transport on coastal FIB (fecal indicator bacteria) concentrations at adjacent beaches in Orange County, California, over three years’ period from October 2001 to September 2004. In order to identify the dominant tempora land spatial patterns of fecal pollutions along the coastal beaches, Empirical Orthogonal Function analysis was utilized for the three-year measurements (n = 39,525) of FIB concentration data from 17 sampling stations. Through the data analysis and the empirical orthogonal function analysis, it was found that the dominant factor effecting coastal FIB concentration is precipitation event and consequent water discharge from Santa Ana River in the area. The Empirical Orthogonal Function analysis revealed the potential non-point FIB sources around northern part of Orange County beaches. In addition, this study confirmed the existing alongshore transport by wave-driven surf zone current and offshore tidal currents. Key words: Fecal pollution, coastal water, rainfall, discharge, alongshore transport.

1. Introduction The coastal zone is the interface between ocean and land, and an important ecological, economic, and recreational resource. Urbanization of the ocean’s coastline has increased significantly the flow of toxic contaminants and pathogenic microorganisms into the coastal zone. Coastal waters have many beneficial uses and they are a transport medium and a final repository for all manner of human waste [1]. The latter inexorably diminishes the former, as evidenced by a wide spectrum of coastal ills, which threatens human health in manifold ways. In the United States, Corresponding author: Youngsul Jeong, Ph.D., professor of natural sciences, main research fields: environmental and energy engineering, environmental impact analysis and assessment, conversion of biomass into bio-ethanol and bio-diesel. E-mail: [email protected].

public coastal beaches are increasingly off-limits due to elevated levels of fecal pollution and other contaminants.

Mitigating

this

pollution

and

identifying pollutant sources in coastal system is complicated by the high degree of complexity of coastal systems [2]. Much of this complexity is associated with the spatial and temporal variability of the

relevant

physicochemical,

biological,

and

oceanographic processes. The near shore concentration of indicator bacteria is controlled by complex and non-linear interactions between human activities and natural processes. Their sources are primarily human in nature: discharge of treated sewage through offshore outfalls and rivers, breaks in sewage collection lines, and runoff from urban and agricultural watersheds [3-5]. The near

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Influence of Rainfall, Discharge, Wave and Alongshore Transport on Microbiological Pollution in Southern California Coastal Beaches

shore loading is determined by land use, population

and discussions. In Section 4, the implications of the

density, and the degree to which communities build

data analysis and the conclusions are presented.

and maintain infrastructure for the capture and treatment of runoff and sewage [6, 7]. After entering the ocean, they are transported by highly dynamic currents, and removed from the water column by die-off and other processes [8, 9]. The combined effect of these processes is the generation of a coastal water quality signal that is highly variable in space and time. Based on 43 years of monitoring data, together with short-term high frequency sampling efforts, a study found that surf zone water quality in Huntington Beach varies over time scales that span atleast seven orders of magnitude, from minutes to decades [7]. The purpose of this study is to evaluate the effects of environmental variables including rainfall, river discharge, and wave and alongshore transport on coastal FIB (fecal indicator bacteria) concentrations including TC (total coliform), FC (fecal coliform), and ENT (enterococci bacteria). In addition, this study will investigate the applicability of multivariate statistical analysis such as EOF (Empirical Orthogonal Function) in determining overall temporal and spatial pattern of coastal FIB concentrations that encompass the period of three years and linear length of 23 km coastal villages. The data from near-daily field monitoring at the coastal waters from Huntington Beach and Newport Beach in Southern California beaches from 2001 to 2004 are compiled. The methods adopted in this study provide a means of analyzing sets of variables including rainfall, river discharge, wave, and alongshore transport, etc. and FIB concentrations at the coastal area which temporal and spatial patterns will be classified and investigated. The remainder of this paper is organized as follows. Section 2 reviews a field site description and empirical orthogonal function technique used in this paper. Section

3

contains

experimental

results

with

monitoring dataset and subsequent statistical analysis

2. Method and Data Beginning July 1, 1999, the State of California mandated FIB monitoring at all public beaches with more than 50,000 annual visitors, and established seven statewide concentration standards for these organisms in the surf zone [10]. Huntington State Beach and Newport Beach in Orange County, California (Fig. 1) host over 5 million visitors per year, and both beaches have suffered from water quality problems for many years. Bathing coastal water quality was assessed based on the surf zone concentration of three groups of FIB—TC, FC, and ENT [11, 12]. The concentration of these three FIB groups are measured five days per week (excluding Friday and Sunday) by the local sanitation district at 17 shoreline sites along a 23 km stretch of the surf zone at Huntington Beach and Newport Beach, California (see map in Fig. 1) [7, 12, 13]. The data period adopted in this study ranges from October 1, 2001 to September 30, 2004 with total number of fecal indictor bacteria concentration measurements over 39,000. Wave conditions, including both direction and height of breaking waves, were recorded by lifeguards at the Huntington and Newport Beach piers (Fig. 1) twice per day, once at 7:00 and again at 14:00 local time. Records of local precipitation were obtained from a rain gauge located at the John Wayne Airport in the City of Santa Ana, approximately 23 km northeast of Newport Beach and Huntington Beach. Stream discharge data were obtained from the site located where Santa Ana River crosses 5th Street in the City of Santa Ana, California. This data was monitored and managed by the U.S. Army Corps of Engineers. The stream gauge site is located relatively close (within 11 km) to the rivers’ ocean outlet, and hence stream flow measured at this site will likely make its way to the ocean.


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Fig. 1 Map of Huntington Beach and Newport Beach in Orange County, California. Black dots in the upper panel represent water quality monitoring sites managed by California State Health Department.

Multi-dimensional spatial-temporal data of FIB for 17 sampling stations were analyzed using a multivariate statistical technique called EOF (empirical orthogonal function) analysis. EOF analysis of the water quality data involves the following steps [14-18]: (1) Organization of the data into a data matrix, X ij , with i and j corresponding to sampling sites and sampling times. Entries in the data matrix represent the log-transformed concentrations of FIB; (2) Preparation of a de-meaned data matrix, Y



y    X ij

ij

 X

i

/ r

so on. The magnitude of the eigenvalue  k denotes the fraction of variance captured by the k th mode. It uses this approach to determine if point and/or non-point sources of fecal pollution are originating along the Huntington and Newport Beaches. EOF analysis is an unbiased statistical approach for identifying the dominant temporal patterns in a time series data set, and how these temporal patterns are distributed spatially—precisely the information needed to answer the questions of identifying the pollution patterns and potential sources.

i

where X i represents the mean of all concentration measurements at the i th station, and ri (   i ) is the standard deviation of all concentration measurements at the i th station; (3) Decomposition of the de-meaned data matrix into a series of EOF modes and associated loadings. The modes are ordered such that the first mode captures the most variance in the de-meaned data set, the second captures the next most data variance, and

3. Results and Discussion Over the period of study, three rainy periods were recorded by the rain gauge at the John Wayne Airport. Most of the rain events were observed during winter season (December to March) and the maximum daily record was about 5 cm/day around March and April 2003. Record of stream discharge (in units of m3/s) measurement at the Santa Ana River is frequently coupled with rainfall (i.e., stream discharge increases

934


shortly after locally recorded rain events, compare red and black curves in the top panel, Fig. 2). The concentrations of the three FIB groups (TC, FC, and ENT) in the surf zone averaged for Huntington and Newport Beaches, respectively, are presented as a set of time series plots in Fig. 2. The concentration of FIB was frequently elevated particularly during and after rain events when stormwater was discharging from the river. For example, during stormwater discharge events, water quality in the surf zone was poor (see California single sample standard violation

frequency marks). During this period, FIB concentrations along the beaches frequently exceeded one or more California State standards. The goal of the EOF approach is to identify the dominant temporal patterns (referred to here as “modes”) in time series data, and then to quantitatively determine how these modes are distributed spatially, by examining the spatial distribution of “loadings” associated with each mode. EOF analysis was carried out in the three FIB species concentrations for the 17 sampling stations along the

Fig. 2 Time series plots of fecal indicator bacteria groups, rainfall and stream discharge, and single sample standard violation number.


Huntington and Newport beaches from October 1, 2001 to September 30, 2004. In general, there are as many modes as there are sampling stations, but most of the higher-order modes capture very little variance in the original data set. The modes are ordered according to the percentage of variance captured by each mode. The temporal patterns associated with these specific EOF modes are presented in Fig. 3, and their associated spatial loadings are presented in Fig. 4. Time series plots of the first and second EOF modes are presented based on each FIB species. Three plots are included for comparison with EOF mode

935

plots. The first is a time series plot of the wave height, the second is the rainfall and stream gauge records, and the third plot is the single sample standard violation numbers. Comparing the raw data plots (Fig. 2) with EOF modes plots (Fig. 3), it was found that the first EOF mode generally captures the trend evident in the raw time series data. All of the first EOF modes—which accounts for 55% TC, 31% FC, 41% ENT of all the variance in the de-meaned and normalized FIB data—are strongly correlated (Spearman correlation coefficient, Sp = 0.45-0.54, p < 0.05) with stream gauge records. In other words, 31%-55% of the variance associated with the

Fig. 3 Wave heights at Huntington and Newport beaches, rainfall and stream gauge records, single sample standard violation number, and first and second temporal eigenvector plots of FIB concentration.

936


de-meaned and normalized FIB measurements in the Orange County surf zone is apparently caused by stormwater runoff. The second mode accounts 8% TC, 11% FC and 10% ENT of the variance and does not exhibit obvious seasonal patterns. EOF loading plots that show spatial variability were presented in Fig. 4. The first EOF loadings are relatively uniform (i.e., constant) across all of the

sampling sites. This result implies that the spatial variability captured by the first EOF mode is relatively homogeneous across all sampling sites; i.e., if the concentrations are rising in one part of the sampling grid, they are rising in the rest of the grid as well. The second EOF loading plots show that sampling stations 3N, 6N, and 9N have consistently higher values than the rest of the stations and suggest

Fig. 4 Spatial loading plots for first and second eigenvector of FIB concentration along with mean concentrations of each FIB group.


937

Fig. 5 Color contour plots of number of wave direction and height measured at Huntington and Newport beaches. Black line demarcates the data point. JFM and JJA represent winter and summer period, respectively.

possible point or/and non-point FIB sources around these stations. The EOF analysis for spatial loadings shows that Huntington Beach in the northern part of the Orange County coast has consistently higher FIB concentrations compared to Newport Beach in southern part of the Orange County coast. To further examine the wave and subsequent effects of it on alongshore current, the wave data was plotted in polar graph format. In order to separately examine the seasonal effects of wave on alongshore current and FIB concentrations, the summer (JJA period) and the winter (JFM period) wave plots are prepared in Fig. 5.The wave data show majority of the waves coming from west during winter and from southwest during summer period, respectively. The wave height ranges

from 1-4 m. It has been confirmed that the westerly and southerly waves in the region are strongly associated with the northerly directional alongshore currents in Orange County beaches [19].

4. Conclusions In this study, land-based monitored coastal water quality data and related environmental data were combined to identify dominant seasonal and annual pattern of microbiological pollutions along the Orange County coast. This study sheds light on the spatial and temporal patterns of FIB concentrations along the coast of Orange County, Southern California; and on the sources and transport pathways that give rise to these patterns. Water sample concentrations of FIB

938


exhibit significant temporal variability at seasonal time scales showing influence of seasonal rainfall events and subsequent discharge from Santa Ana River. The EOF analysis indicates that the spatial variability among sampling site in 23 km stretch of the beach is fairly homogeneous across the sampling points. In addition, it indicates consistent high concentrations of FIB concentration at 3N-9N monitoring stations and it indicates the potential non-point sources of fecal pollution at the area. Collectively, these results point to runoff (from local storm drains and from river draining into coastal area), as primary sources of FIB in Orange County coastal area. From the perspective of fate and transport of microbiological pollutants in the coastal area, once FIB enter the coastal waters, they are transported laterally by the alongside tides, to a greater or lesser extent, depending on location. From the previous study, it was confirmed that the water flowing out of the Talbert Marsh during ebb tides can impact surf zone water quality at Huntington State Beach directly upcoast of the Talbert Marsh outlet, provided that ocean waves strike the beach in an upcoast direction [19]. It was revealed that the along-shore flux of coastal beach water is up to 300 times larger than the cross-shore flux of coastal beach water [19]. These studies showed that once microbiological pollutants captured in the coastal water in Huntington Beach and Newport Beach area, they would be transported significant distances along the coastal area before effectively being diluted by off-shore ocean water. From the perspective of best-management-practice of the coastal water quality, the results of this study along with previous studies [20] imply that managerial acts should be taken to reduce the discharge of microbiological pollutants from inland sources of surface water runoff, such as tidal outlets and river discharges.

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T.J. Culliton, Population, Distribution, Density and

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Growth: A State of the Coast Report, NOAA's State of the coast report, National Oceanic and Atmospheric Administration, Silver Spring, Md., 1996. J.H. Kim, S.B. Grant, Public mis-notification of coastal water quality: A probabilistic evaluation of posting errors at Huntington Beach, California, Environmental Science and Technology 38 (2004) 2497-2504. K. Schiff, M. Stevenson, San Diego regional storm water monitoring program: Contamination inputs to coastal wetlands and lagoons, Bulletin Southern California Academy of Sciences 95 (1996) 7-16. H.M. Solo-Gabriele, M.A. Wolfert, T.R. Desmarais, C.J. Palmer, Sources of E. coli from coastal subtropical environment, Applied and Environmental Microbiology 66 (2000) 230-237. R.S. Fujioka, Monitoring coastal marine waters for spore forming bacteia of faecal and soil origin to determine point from non-point source pollution, Water Science and Technology 44 (2001) 181-188. M.A. Mallin, K.E. Williams, E.C. Esham, R.P. Lowe, Effect of human development on bacteriological water quality in coastal watersheds, Ecological Applications 10 (2000) 1047-1056. A.B. Boehm, S.B. Grant, J.H. Kim, S.L. Mowbray, C.D. McGee, C.D. Clark, et al., Decadal and shorter period variability of surf zone water quality at Huntington Beach, California, Environmental Science and Technology 36 (2002) 3885-3892. C.E. Chamberlain, R.A. Mitchell, A decay model for enteric bacteria in natural waters, Water Pollution Microbiology 2 (1978) 325-348. N. Mezrioui, B. Baleux, M. Troussellier, A microcosm study of the survival of E. coli and Salmonella typhimurium in brackish water, Water Research 29 (1995) 459-465. J.H. Kim, S.B. Grant, Public mis-notification of coastal water quality: A probabilistic analysis of posting errors at Huntington Beach, California, Environmental Science and Technology 38 (2004) 2497-2504. J. Bartram, G. Reese, Monitoring bathing water: A practical guide to the design and implementation of assessments and monitoring programmes, World Health Organization, 2000. A.B. Boehm, S.B. Weisberg, Tidal forcing of enterococci at marine recreational beaches at fortnightly and semidiurnal frequencies, Environmental Science and Technology 39 (2005) 5575-5583. J.H. Kim, S.B. Grant, C.D. McGee, B.F. Sanders, J.L. Largier, Locating sources of surf zone pollution: A mass budget analysis of fecal indicator bacteria at Huntington Beach, California, Environmental Science and Technology 38 (2004) 2626-2636.

Influence of Rainfall, Discharge, Wave and Alongshore Transport on Microbiological Pollution in Southern California Coastal Beaches [14] W.J. Emery, R.E. Thomson, Data Analysis Methods in Physical Oceanography, Elsevier Sciences, Amsterdam, 2000. [15] C.D. Winant, D.L. Inman, C.E. Nordstorm, Description of seasonal beach changes using empirical eigenfunctions, Journal of Geophysical Research 80 (1975) 1979-1986. [16] S. Harms, C.D. Winant, Characteristic patterns of the circulation in the Santa Barbara Channel, Journal of Geophysical Research 103 (C2) (1998) 3041-3065. [17] S.W. Lyons, Empirical orthogonal function analysis of Hawaiian rainfall, American Meteorological Society 21 (1982) 1713-1729. [18] J.E. Peak, W.E. Wilson, R.L. Elsberry, J.C. Chan,

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Forecasting tropical cyclone motion using empirical orthogonal function representations of environmental wind fields, Monthly Weather Review 114 (1986) 2466-2477. [19] S.B. Grant, J.H. Kim, B.H. Jones, S.A. Jenkins, J. Wasyl, C. Cudaback, Surf zone entrainment, along-shore transport, and human health implications of pollution from tidal outlets, Journal of Geophysical Research 110 (2005) C10025. [20] S.B. Grant, B.F. Sanders, A.B. Boehm, J.A. Redman, J.H. Kim, R.D. Mrse, et al., Generation of enterococci bacteria in a coastal saltwater marsh and its impact on surf zone water quality, Environmental Science and Technology 35 (2001) 2407-2415.

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