Feasible Solutions for Land Subsidence and ...

2017

Picture source: www.mekongeye.com

Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta Annisa Noyara Rahmasary | 5524008

Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

by Annisa Noyara Rahmasary

Compiled for a tailor made course under a joint project “Rise and Fall: strategies for the subsiding and urbanising Mekong Delta (Vietnam) facing increasing salt water intrusion”

Supervisor: Carel Dieperink

Faculty of Geoscience Utrecht University The Netherlands


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Table of content List of Figures ....................................................................................................................................... 3 List of Tables ........................................................................................................................................ 3 Abbreviation List ................................................................................................................................... 4 1. Introduction ...................................................................................................................................... 5 1.1.

The Vietnam Mekong Delta..................................................................................................... 5

1.2.

Problem Definition ................................................................................................................... 5

1.3.

„Rise and Fall‟ Project Description .......................................................................................... 6

1.4.

Research Objectives ............................................................................................................... 6

2. Methodology .................................................................................................................................... 7 2.1 Scope of Research........................................................................................................................ 7 2.1.

Data collection ......................................................................................................................... 7

2.2.

Data Analysis .......................................................................................................................... 8

3. Findings ........................................................................................................................................... 8 3.1.

The Theoretical Solutions ....................................................................................................... 8

3.2.

Critical Conditions for Successful Measure Implementation ................................................. 15

3.3.

The Current VMD Status ....................................................................................................... 17

4. Discussion ..................................................................................................................................... 20 5. Conclusion ..................................................................................................................................... 21 6. References .................................................................................................................................... 22 Appendix ............................................................................................................................................. 24


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List of Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

................................................................................................................................................. 5 ................................................................................................................................................. 8 ............................................................................................................................................... 11 ............................................................................................................................................... 12 ............................................................................................................................................... 13

List of Tables Table 1 Table 2 Table 3 Table 4 Table 5

.................................................................................................................................................. 9 ................................................................................................................................................ 12 ................................................................................................................................................ 15 ................................................................................................................................................ 16 ................................................................................................................................................ 17


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Abbreviation List ACW

Adaptive Capacity Wheel

AFD

Agence Française de Développement

ASR

Aquifer Storage and Recovery

DARD

Departments of Agriculture and Rural Development

DONRE

Departments of Natural Resources and Environment

HCMC

Ho Chi Minh City

MAR

Managed Aquifer Recharge

MARD

Ministry of Agriculture and Rural Development

MDP

Mekong Delta Plan

MONRE

Ministry of Natural Resources and Environment

NWO

Nederlandse Organisatie voor Wetenschappelijk Onderzoek Netherlands Organisation for Scientific Research

RWH

Rainwater Harvesting

SGMA

Sustainable Groundwater Management Act

SWT

Subsurface Water Technologies

VMD

Vietnam Mekong Delta

WWTP

Wastewater Treatment Plant


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1.

Introduction

1.1. The Vietnam Mekong Delta Together with Cambodian Mekong Delta, The Vietnam Mekong Delta (VMD) is the downstream 2 region of The Mekong River Basin which drains 795.000 km land area from Tibetan Plateau to its mouth in the South China Sea (Van Manh et al., 2015). The VMD can be recognized as vast floodplains at the far south of Vietnam where the average elevation in the area is 0,8m above sea level (MDP, 2013). Likewise the other deltas in the world, the VMD is densely populated where approximately 17 million people live in 13 provinces in the delta with Can Tho city as its center (ibid). Among the other Mekong Basin subsystems, the VMD is known for its heavy human interventions. Road network, channel, dikes, sluices, and other hard infrastructures create more compartments where sluice gates connect these smaller isolated areas to the main channel for agriculture purposes (Van Manh et al., 2015). However, these structures put more pressure by diminishing land surface with a lack of proper drainage (Erban et al., 2014). Additionally, the Vietnam national government ambition to promote the delta as the „Asian rice bowl‟ (MDP, 2013; Smajgl et al., 2015; Van Manh et al., 2015); encourages further agriculture development by building supporting infrastructures. Furthermore, on-going urbanisation in the VMD intensifies land use change during recent years. This process leads to increasing population in the delta which affects the water demand. The drinking water source for these urban areas comes from groundwater wells (MDP, 2013).

Figure 1 The Vietnam Mekong Delta (MDP, 2013)

Since this report aligns its content with the Rise and Fall project, the study in the VMD is focused on the Soc Trang Province. Located in the southeast part of the VMD, Soc Trang has a low and flat terrain topography with sand dunes that is dominated by agriculture and aquaculture production land. Accordingly, agriculture production dominates the economic activity of this province up to 83% (Thanh, 2016). However, saline intrusion divides this province into three vulnerable zones: the least prone area in the northernmost district, an area with seasonal intrusion, and a saline aquaculture dominated zone, surrounding Vinh Chau District, with all year long intrusion (Thanh, 2016). Meanwhile, though Erban et al. (2014) provided the data of land subsidence rate on the basin level, detailed information about subsidence in the province level of the Soc Trang is lacking (Tri, Dieperink, & Otter, 2016).

1.2. Problem Definition In recent years, the term „sinking cities‟ has come under the spotlight and has triggered many studies for the group of vulnerable deltas around the world, including the VMD. Sinking city refers to an area with a major problem in land subsidence which leads to descending land surface. From InSAR-based data, the VMD is sinking at the rate of 1-4 cm/year with deep depression cones located alongside northeast direction of Ho Chi Minh City (HCMC) (Erban et al., 2014). In the other side, the compaction-based subsidence rates in the delta are ranging from 0.28–3.1 cm/year (ibid). The area with highest land subsidence rates in the VMD is the northeast of HCMC and Ca Mau, the most populated city in the delta. The trigger behind worsening land subsidence over the cities is pumping induced compaction, in addition to natural consolidation and aggradation (Erban, Gorelick, & Zebker, 2014). Extensive groundwater abstraction in the VMD is well known as one of the significant drivers that contribute to the total land subsidence (Minderhoud et al., 2015). Fresh groundwater was previously used to supply the domestic water use only, but the recent development results in increasing total freshwater demand in the delta. It stems from the fact that higher population in the Mekong delta Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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attracts land use change to the water-intensive paddy field and aquaculture landscape (IUCN, 2009). Also, Vietnam‟s national government selected the VMD as the strategic importance region for Vietnam‟s national food security (Smajgl et al., 2015). Meanwhile, the hard structure development in the upstream area (mostly in Laos, China, and Thailand) changes the river flow regime (MDP, 2013). This adds more complexity to the water balance of the delta downstream. Extreme rates of groundwater abstraction also result in saline intrusion to the aquifer. Changing well location makes the negative loop stronger by causing drawdown in groundwater table which inducing saline intrusion. Erban et al. (2014) added that polluted surface water also triggers the people to abstract more groundwater for their water supply. The pollution in the surface water comes in the form of high coliform and pesticides concentration (Vuong, Lam, & Van, 2015). 1.3. ‘Rise and Fall’ Project Description According to the official website (Rise & Fall Project, n.d.), Rise and Fall project is a Netherlands Organisation for Scientific Research (NWO) granted research that conducted under a consortium between the Faculty of Geosciences of Utrecht University, Deltares, College of Environment and Natural Resources of Can Tho University, Southern Institute of Water Resources Research, and Division of Water Resources Planning and Investigation for the South of Vietnam, including the Soc Trang Province‟s Departments of Natural Resources and Environment (DONRE) and Departments of Agriculture and Rural Development (DARD). This project officially started in 2014 and expected to present all the outcomes in 2018. The long-term objective of this project is to build up the individuals and organization capabilities toward sustainable strategies against groundwater extraction that leads up to land subsidence and saltwater intrusion in the increasing urbanising effect of the Mekong Delta (Vietnam). The project is divided into four focuses (Future Delta, n.d.): 1. Subsurface characterization and subsidence. See the impact of the existing issues using different scenarios of delta management. 2. Fresh and saline groundwater dynamic. Understand the dynamic behavior of fresh and saline groundwater toward Mekong‟s hydrogeological system. 3. Salt intrusion and flood risks in estuarine channel networks. Observe and estimate the statistical changes in flooding and intrusion. 4. Governance strategies for sustainable management. Acquire strategies for both public and private stakeholders to cope with the issues Five working packages are assigned to focus on different targets within the Rise and Fall project. This report concentrates on the objective of the third working package: WP 3.1: Governance strategies for sustainable management and acts as follow-up Water governance is needed to support the understanding that shape and build the individual and organization capacity in the changing VMD system.

1.4. Research Objectives The prolonging issues of land subsidence and saltwater intrusion in the VMD need to be approached from various perspectives. This study offers the overview of theoretically possible measures to address these issues alongside their critical conditions to successfully implement the measures. In the end, a recommendation is constructed from assessment result based on the presence of the decisive conditions. In particular, the Soc Trang Province is used as a specific study area to accommodate the approach where definite characters related to study area are needed. It is expected that the result of the Soc Trang area can also be applied to other provinces in the VMD.

1.5. Research Question To attain the stated research objectives, the main research question is formulated as follows: What measures are the most feasible for addressing land subsidence and saltwater intrusion in the VMD? The following sub-questions are posed to assist the process of answering the main question: 1. What are the theoretically available measures to accommodate the land subsidence and saltwater intrusion in the VMD?


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2. What are the critical conditions that need to be achieved to secure a favorable implementation result? 3. To what extent are the critical conditions present in the existing VMD currently?

2.

Methodology

2.1 Scope of Research Referring to the objectives, this study covers the possible measures that can be applied to answer two particular issues in the VMD, i.e. land subsidence and salt water intrusion. These two specific concerns emerge in the delta area due to the combination of diminishing outflow from the upstream area and changing land use in the delta itself (MDP, 2013). These factors reinforce the negative feedback loop that connects VMD‟s freshwater demand and supply, which relate to both surface and groundwater reservoirs. However, this study focuses on the impact of both issues on groundwater state in the delta area, particularly for the definition of saline intrusion. Nevertheless, surface water is still addressed in the solution proposal due to the strong affiliation of both freshwater sources. In accord with the work of WP 3.1 of Rise and Fall project, the Soc Trang Province is chosen as the specific study area. Due to its location in the coastal zone of the VMD, the threat of land subsidence and saltwater intrusion in Soc Trang is deemed as more pressing than the others. Even though the focus of research is directed toward the issue in the Soc Trang Province, the application of the offered solutions is liable for the other regions as well. Especially, considering the groundwater system within the delta could not be limited by such administrative borders.

2.1. Data collection The main method used in this study was desk research. This approach utilized some scientific articles retrieved from Google Scholar (with UBU-link provided by Utrecht University‟s library), Scopus, the official reports from projects related to the issues, websites, and online news articles. Most of the information used in this study was collected from secondary data. Since this study supposes to provide information to the Rise and Fall project, the first desk research was conducted to comprehend the project‟s background, description, and objectives. As referred before, this project has been conducted since 2014. Hence, some of the findings from Rise and Fall project report were used as complementary information even though most of these results have not been published. To address the first sub-question, scientific articles and study reports of the previous projects in the VMD, as well as past or current research in other areas, were used. The Mekong Delta is a living laboratory of delta related research that attracts many local and international scientists. In the search column of Google Scholar and Scopus, keywords such as land subsidence, saltwater intrusion, mekong delta, sinking delta, and groundwater abstraction are used to collect various possible measures. The most recent comprehensive project in the VMD produced a report titled the Mekong Delta Plan (MDP) in 2013. The report covered a broader range of aspect in the delta management whereas this study, as well as Rise and Fall project, provides an in-depth perspective on land subsidence and saltwater intrusion. Meanwhile, some learning points were inferred from the other deltas based on the article „Sinking coastal cities’ by Erkens et al. (2015). It also included mega cities, which not located in a delta but experience high risk and vulnerability to land subsidence and groundwater related problems. The knowledge from these different areas was gathered to complete the overview of theoretically possible solutions. The second sub-question is addressed by providing an overview table of the critical conditions for each theoretically possible measure. The critical conditions are a set of requirements which need to be met for a successful implementation of the measure. These conditions cover both technical and institutional requirements. The technical conditions are the technical prerequisites which have to be fulfilled for a fruitful application of one measure. Meanwhile, this report used Adaptive Capacity Wheel (ACW) (Gupta et al., 2010) as a reference to classify the various aspects from institutional requirements which are needed during measure‟s utilization. Recent data and information were needed to resolve the third sub-question. This report refers to unpublished thesis of Thanh (2016) and deliverable report by Tri et al. (2016) for Rise and Fall project. Both documents contain detailed and primary information about the present condition in the Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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VMD, with a specific focus on Soc Trang. Additional information was provided by recently published news from various websites. Also, the expert opinions were gathered by personally contacting some professional via email or semi-structured interview to understand the nuance of the ground condition in the study area (details on the interviews in Appendix 1). Their opinions were compiled to further assessing the practicability of each offered solutions. The group of expert consists of researchers that work in preceding projects in the VMD, as well as others who work on the delta with a similar problem.

2.2. Data Analysis The literature review and interviews were used to collect best measures around the world and list out the critical conditions. The selected measures are those which frequently mentioned in some articles with different study case areas. This report describes the current condition in the VMD and assesses whether it possess the critical conditions. At first, the offered solutions are briefly described alongside its critical conditions which need to comply. Some of these factors were explicitly stated in the source articles while others were derived from the literature review. Two overview tables were created to summarize the overall critical conditions of all proposed measured. The relevancy of each critical condition was estimated for every measure. Furthermore, the existence of each critical condition was assessed in the present day of the VMD using literature and interviews. The interview summaries were written and sent back to the interviewee for checking whether the main idea inferred from the interview was fully comprehended. The feasible measures were then decided based on the critical conditions‟ presence. In the end, Strengths, Weakness, Opportunities, and Threats (SWOT) analysis was applied to evaluate the chosen possible measures.

3.

Findings

3.1. The Theoretical Solutions

Figure 2 The cumulative land subsidence rate in the cities around the world. Absolute sea level rise is included as reference (Erkens et al., 2015)

In recent years, researchers have found a wide range of solutions proposal to cope with climate change effect in a delta (see Volume 372 of IAHS Proceeding). These options can be categorized into soft and hard options (Smajgl et al., 2015) where soft options focus on strategies and management aspect while hard options aim for investment in water infrastructures. Erkens et al. (2015) summarized the measures to address the land subsidence by dividing the options into: 1) mitigation for human-induced land subsidence (diminishing pumping, applying aquifer storage recovery, using lighter building materials) and 2) adaptation for natural and remaining human-induced land subsidence (reintroducing sediment in the delta, build higher levees, better spatial planning, governmental embedding). Meanwhile, saltwater intrusion affects both salinity in groundwater and surface water. Hence, similar measures to resolve land subsidence also prevent the worse impact of Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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this intrusion to the aquifer. Regulating saltwater intrusion in surface water is more complicated by installing gates and sluices in the canals (MDP, 2013). While agriculture is the most affected sector in the VMD, the farmers usually resort to adapt the high salinity by changing their plant variety (Thanh, 2016). Throughout the years, land subsidence persists as a hidden but urgent issue in many deltas around the world. Coincidentally, the worst regions with land subsidence are the megapolitan cities in both developing and developed countries. Figure 2 displays the comparison between six cities which usually addressed as heavily impacted by land subsidence. Some of the cities above had implemented measures to mitigate the issue. While some of them have succeeded to alleviate the impact, the rest are still striving to see the result from the implemented solutions. For example, Tokyo land subsidence rate has stabilized since 1970 as the outcome of their policy enforcement while Jakarta still currently struggling with the problem (Erkens et al., 2015). Selected cities in Table 1 were chosen based on cases in Figure 2 with additional cities with the different coping method for both land subsidence and saltwater intrusion problems. Table 1 Measures taken to resolve land subsidence and saltwater intrusion issue in various countries No

City

Measure Restriction policy for groundwater extraction

1

Tokyo, Japan Raising the groundwater supply chain efficiency

Source Sato, Haga, & Nishio (2006); Kaneko & Toyota (2011) Sato, Haga, & Nishio (2006); Kaneko & Toyota (2011)

2

Shanghai, China

Groundwater recharge and sustainable groundwater use

Erkens et al. (2015)

3

Bangkok, Thailand

Groundwater use restriction by zoning

Endo (2011); Erkens et al. (2015)

4

Ho Chi Minh City, Vietnam and Jakarta, Indonesia

Tax procedure for private companies who use groundwater source

Erkens et al. (2015)

5

Netherlands

6 7

Lower Bangladesh Delta Plain Upper Bangladesh Delta Plain

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Houston, USA

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Silicon Valley, USA

Building canals, closing tidal area, raising dikes, and creating polders. Optimizing subsurface freshwater lens in saline aquifer area Aquifer storage, recovery of freshwater, deep well injection Conjunctive use of surface and groundwater as water source, riverbank infiltration, infiltration basin Importing freshwater from other area using pipelines and canals construction also dam storage Constructing leeves, raising grades for railroads and roads, enlarging bridges and sewers Diversion of high-quality surface water

Erkens et al. (2015) Zuurbier et al. (2016) Faneca Sanchez et al. (2015) Faneca Sanchez et al. (2015) Ingebritsen & Galloway (2014) Ingebritsen & Galloway (2014); Hanson (2015) Hanson (2015)

Based on the collected literature, two main concepts are deemed as the key factor of mitigating land subsidence and saltwater intrusion issues: reducing groundwater exploitation and extending the variety of water resource. The elaboration of these two notions results into four groups of measure below: 1) Reducing pressure for groundwater abstraction, 2) Expanding the source of water supply, 3) Managing the existing land use, and 4) Installing hard options.

Reducing pressure for groundwater abstraction One of the root problems that prompt land subsidence in the VMD is the inability of surface water to meet the water demand. The current problem with the surface water in the VMD includes the high salinity, especially during dry season, and low water quality (MDP, 2013). These causes more groundwater are extracted for drinking water and agricultural purposes. Reducing the pressure to the groundwater means that the freshwater supply is expected to shift from uncontrolled groundwater extraction to surface water. It includes regulating abstraction permit, improving water quality using water treatment plant, and fixing the water distribution efficiency. Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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1) Regulating abstraction permit Industrial Water Law solved the issue of land subsidence in the coastal Tokyo during the 1960s (Kaneko & Toyota, 2011). The economic boom drove the industrial and residential sector to abstract higher rate of groundwater until the government introduced the law in 1960. In accordance, the government instituted the Building Water Law and Environmental Preservation Ordinance. These three legislations regulate the pumping facilities‟ structural design, such as the outlet cross section and the strainer depth (Sato, Haga, & Nishio, 2006). The imposition of the regulations in Tokyo coincided with the migration of the water-intensive industries out the town. Hence the dependence toward groundwater was decreasing. Public awareness about the issue was high due to the visible impact that caused by land subsidence, i.e. damaged infrastructures (Kaneko & Toyota, 2011). In other Asian cities such as Jakarta, Bangkok, and HCMC, the government acted out similar regulations to handle the excessive groundwater extraction (Erkens et al., 2015). Bangkok‟s Groundwater Act charges tax for groundwater abstraction which comes into effect in 2004 when the tax for groundwater was more expensive than the one for surface water (Endo, 2011). Meanwhile, The Governor of Jakarta has banned deep groundwater usage in all government and public buildings as the beginning of the transition to piped water supply (Erkens et al., 2015). However, the actual result of this implementation differs from one city to another due to the different public behaviour and government capacity. In a different example, California recently passed a new regulation to govern the groundwater use since it became the main supply due to the prolonging and intensive drought spell in the area. The state legislature approved the Sustainable Groundwater Management Act (SGMA) in September 2014. This new bill works differently with the regulation in Tokyo, Bangkok, and Jakarta where their government limits the groundwater use wherein SGMA supports the enforcement of sustainable groundwater management at the local level (Reterrer, 2015). 2) Improving surface water quality In the common scheme, the main water supply comes from surface water. Groundwater abstraction is the last resort after surface water and natural springs. In the VMD case, groundwater use stems from the deteriorating surface water quality, not the quantity. Hence, treatment plants are required to raise the quality of surface water in the delta. Water treatment plants cover both wastewater treatment plant (WWTP) and drinking water production plant. The 2013 Mekong Delta Plan incorporated the development of wastewater treatment plan in the future scenarios, especially in the no-regret scenario (MDP, 2013). In that scenario, it is mentioned that industrial WWTPs are important for immediate actions, alongside the upgrade of other water 3 infrastructures such as sewerage (ibid). A 10 000 m water treatment plant in An Nghiep, Chau Thanh District of Soc Trang Province has been operating since April 2015 as the part of Climate Change and Water Supply in the Mekong Delta Project (Thanh, 2016). Also, the government had planned the development of other regional scale WWTP to provide the safe and sustainable water supply for the public. This initiation is now still in the phase of seeking for financial partners for this project realization (ibid). Furthermore, integrating wastewater treatment in the pollution sources (e.g. aquaculture production chain) will reduce WWTPs load by reducing the waste emission to the surface water. Anh et al. (2010) proposed one example to conform the practice of treating wastewater in the frozen Pangasius fillet production system. Assuming that the others (particularly industry sector) apply the integrative system as well, it will lower the load of WWTP to clean the water before discharging back to surface water. However, more stringent regulation system is needed to ensure this policy‟s enforcement. Otherwise, there will be another case like Vedan (Taiwanese based MSG producer) who continued to discharge their waste into the river near HCMC until local reporters exposed the impact toward its adjacent fish farming (Kleinen, J., 2015). 3) Fixing the water distribution efficiency The rapid growth of urbanization in the delta leaves the infrastructure reinforcement in the VMD behind. The current infrastructure of water distribution is inadequate to supply the amount of user in the delta where it only covers 8-12% of the rural households (Wilbers et al., 2013). Furthermore, poorly maintained water distribution system causes a large amount of wasted water. Most of the time, this refers to a significant amount of leakage in the piping network where nearly Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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over a third of the water is wasted (AFD, 2014). In correlation with WWTP roles in the VMD, improving water system efficiency means wasting less high-quality water from the system. Vuong et al. (2015) mentioned that enhancing the water supply chain efficiency can be done by fixing the leakages in the wells and distribution pipes. In practice, distribution efficiency is improved by constructing or renovating the existing WWTPs and installing new pipes or replacing broken links. Agence Française de Développement (AFD) funded a project related to building WWTPs and repairing the water pipeline in six provinces within the VMD during 2011-2015 (AFD, 2014). The collaboration project between the Dutch Government, Vitens Evides International (VEI), and Soc Trang Water Company which erected the WWTP in An Nghiep also aims in expanding water distribution network for low-income households in HCMC, Soc Trang, and Tra Vinh (Thanh, 2016). Expanding alternative sources for water supply Even with the effort of shifting back the freshwater supply to surface water, there is a need to seek for other (virtually) alternative sources. It said „virtual‟ alternative sources because the main sources of water can always be traced back to either surface or groundwater. Figure 3 explain an example of ideal urban water management that depends on diverse water resources, including the virtual sources such as recycled water. Varied water sources might have different water quality. Hence, water use from one source should be correspondingly allocated to a Figure 3 An example of an ideal townsite‟s water management plan with proper sector to achieve higher variety in both water resources (supply) and water use (demand) efficiency. This group of solutions according to DAFWA (2016) proposes to add the available water amount that can be extracted from the system without further damage in the water balance. It covers the application of artificial aquifer storage, conjunctive water use, and rainwater harvesting (RWH). 1) Artificial aquifer storage Besides imposing the regulation that restricts groundwater abstraction, Tokyo Metropolitan Government claimed that their recharge and pumping rate is nearly in equilibrium by specifying that any groundwater pumping facilities must be equipped with infiltration pit (Sato, Haga, & Nishio, 2006). Infiltration pit is one measure that is expected to accommodate higher recharge rates toward aquifer. Broader and newer management term to confer this measure is known as Managed Aquifer Recharge (MAR). UNESCO remarks MAR as a promising adaptation to address the issue of hydrological variability (UNESCO, n.d.). Its concept principally enables better percolation rates of surface water into subsurface which results in an optimal water cycle (Stefan, 2014). The practices of MAR technology encompass a broad range of selection that aims for alleviating the amount of water storage at the same time enhancing its quality. Maliva & Missimer (2012) divided MAR implementation into the following three systems: subsurface injection well, surface or near surface water application (spreading), and natural process enhancement. The selection of proper MAR technology is most influenced by the topographical and hydrogeological architecture of the study area (Stefan, 2014). Vuong et al. (2015) added that potential regions that more suitable for the aquifer recharging process should be identified. The preferable aquifers would be located in a region with sufficient precipitation and lower saline intrusion. Table 2 represents the information of groundwater use and the existing states of different aquifers in the VMD region.


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Table 2 The states and characteristic of seven aquifer systems in the VMD (Vuong et al., 2015)

Aquifer system Holocene Upper Pleistocene Upper-middle Pleistocene Lower Pleistocene Middle Pliocene Lower Pliocene Upper Miocene

Abbrev iation Qh qp3 qp2-3 qp1 2 n2 1 n2 3 n1

Abstraction 3 rate (m /day) 17,851 114,945 997,514 130,077 477,395 87,652 N/A

Fresh groundwater 2 area (km ) 2,889 10,494 14,941 13,647 14,014 16,269 10,494

Saline groundwater 2 area (km ) 14,788 28,974 24,338 25,693 22,253 18.277 28,974

In the coastal zones of Bangladesh, deep well injection procedure called Aquifer Storage and Recovery (ASR) maintains seasonal water storage, replenishes overdraft, serves as pressure barriers from saltwater intrusion, and raise the drinking water supply‟s quality (Faneca Sanchez et al., 2015). Due to the high annual precipitation rate in Bangladesh coastal area, this method is used to store surplus rainwater in the monsoon season. For a successful implementation, ASR method requires detailed characteristic of the local confined aquifer and the injected-water quality (ibid). A modified ASR method can be employed to create freshwater lenses in the subsurface zone. In lower delta plain of Bangladesh, this procedure is applied to prevent these lenses from turning into brackish one during the dry period (Faneca Sanchez et al., 2015). Zuurbier et al. (2016) categorize three subsurface water technologies (SWT) to deal with freshwater source in a saline zone: (1) ASR-coastal that preserve freshwater surpluses in confined brackish-saline aquifer, (2) the Freshkeeper that impede well salinization by intercepting and desalinating brackish water, and (3) the Freshmaker that combine both ASR and the Freshkeeper function. The similar yet more specific concept was tested in the Haringvliet, Figure 4 The description of SWT practices: (a) Netherland two years ago in the form of Freshmaker, a horizontal well to recover shallow „balance island‟ (R. Dam, personal freshwater lens, (b) ASR-coastal, multiple penetrating communication, January 13, 2017). By wells in a single borehole that inject freshwater adding a human-made island in one estuary, (usually, harvested rainwater), (c) Freshkeeper, a well system that intercept brackish water from the it provides a freshwater reservoir as it lower part of aquifer and convert it into freshwater captured precipitation that falls on the new land. The resulting freshwater lens (Zuurbier et al., 2016) consequently creates a barrier for saltwater intrusion. Although the experiment in the Haringvliet was discontinued, this concept is expected to be applicable in other areas (DWS, 2015). Both SWT and „balance island‟ approach addresses land subsidence and saltwater intrusion because they are meant to conserve freshwater reservoir in the saline area. 2) Optimizing conjunctive use of water The definition of „conjunctive use‟ varies from one paper to another. In general, it defines the allocation system of both water quality and quantity from surface water and groundwater for an acceptable water supply (Safavi, Darzi & Mariño, 2010). An alternative interpretation of conjunctive use is a procedure of mixing higher and poorer quality water to expand available water storage while maintaining the water quality (Vuong et al., 2015). Specifically, this kind of water supply reliability can be attained by redirect surface water, either streams or reservoirs, to a subsurface storage. In the actual implementation, one option to carry out the conjunctive water use is by applying riverbank infiltration and infiltration basin (Feneca Sanchez et al., 2015)


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In the upper delta plain of Bangladesh, available fresh groundwater comes from the deep aquifer, while shallow aquifer is contaminated by arsenic pollution. However, there are pockets of deep saline groundwater that might contaminate the fresh groundwater when it is disturbed (Feneca Sanchez et al., 2015). Riverbank infiltration usually consists of a series of pumping wells installed in the riverbank area. Once the pumping started, it lowers the water table near the river which causes the water from the river being abstracted instead. The polluted surface water (river) is purified through its passage to the production well in the riverbank area (ibid).

Figure 5 Possible practices of aquifer recharge to support conjunctive use (Faneca Sanchez et al., 2015)

A different approach to achieve the conjunctive water use is using an infiltration basin. Similar with the infiltration pit that is mentioned in Tokyo case (Sato, Haga, & Nishio, 2006), this measure is installed by excavating an area which geologically suitable to let the water infiltrate to the subsurface (shallow aquifer). Infiltration basins offer efficient use of space and require simple maintenance. These small-medium size basins can provide adequate water supply for small-scale agriculture purpose. Meanwhile, larger basins need wider land surface above shallow aquifer which sometimes difficult to acquire. Hence, government or water authorities usually organize the development of larger infiltration pits for urban water supply (Feneca Sanchez et al., 2015). 3) Rainwater harvesting The procedure of collecting rainwater for supplying water need has the longest historical record with an evident correlation between human response and abrupt climate change fluctuations (Pandey, Gupta & Anderson, 2003). Over the centuries, the harvested water provides the resource for various purposes, from agriculture fields to domestic water supply. In the adaptation of climate change, rain harvesting in municipal area employs building‟s roof to collect rainwater and tanks to store the accumulated water. The basic installation also equipped with storage roof, connector pipes, and filtering layers (Baguma, Loiskandl & Jung, 2010; Farreny et al., 2011; Wilbers et al., 2013). In some countries, the application of RWH starts with a pilot village to see the barriers and opportunities of implementing the procedure on a larger scale. For example, small-scale RWH in 3 nine houses and churches in the village Kido Island (Republic of South Korea) use 4m rainwater tank for each building to store the collected water from the housing rooftop. A sedimentation tank with 500 micron-filter-strains treats this water which can be pumped directly to houses for drinking purpose (WWI, 2012). Meanwhile, the Department of Agriculture and Food in Western Australia (DAFWA) conducted a larger scale of RWH as a part of stormwater reuse project (DAFWA, 2016). Instead of letting each household collect and treat their own collected water, DAFWA 3 project in the Shire of Wagin created a „brown‟ dam which manages up to 25 000 m collected stormwater and town catchment runoff. The stored water in this dam can be used to irrigate and maintain cityscapes such as sports grounds, parks, and public gardens (ibid). Due to its simplicity, installing RWH is considered as the most suitable measure for a municipal area to gain their independent water supply. Also, the officials of Soc Trang Province had initiated a study to reinforce the application of RWH for drinking water purpose which proved that Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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harvested rainwater is one of the best drinking water sources with prior fitting treatment (Wilbers et al., 2013). However, some aspects need attentions to secure the acceptable water quality while maintaining the harvested water quantity. One of the main concerns to carry out RWH is the roof selection which includes its material, slope, and roughness (Farreny et al., 2011). Since the local climate determines the type of roof installed in the area, it also becomes one of the determining factors.

Managing existing land use In a bigger picture, proper land use management gives an opportunity to reduce land subsidence and saltwater intrusion. This measure relates to the first category of reducing the pressure on the groundwater demand. Intensive groundwater abstraction in the VMD region started at the same time as the initial period of rapid urbanization and expansive agriculture. Land use management in the delta directly governs the corresponding water use and distribution system. As mentioned before, agriculture practices occupy most of the VMD land surface (Thanh, 2016). It includes large areas dedicated to coastal aquaculture, which is currently dominated by shrimp farming. The recent Mekong Delta Plan highlights the importance of land use management for future resilience by proposing the four scenarios which based on different land use development in the future (MDP, 2013). Especially for delta‟s coastal zone, the proposed scenarios attempt to control land subsidence and saltwater intrusion issue by halting groundwater depletion and fostering a brackish environment for aquaculture activity (ibid). In Indonesia, Jakarta‟s provincial government has addressed land subsidence as one of the main consideration for the zoning plan, RDTR (Rencana Detail Tata Ruang, Detailed Land Use Plan). For example, if it is known that 30% of the area is affected by land subsidence then the available area for development, which usually water intensive, is the rest of it. Detailed zoning in Jakarta is legitimized as regional regulations with a fine sanction for any violations (E. Saputra, personal communication, January 12, 2017). In another promising approach, there are suggestions to revive nature-based land use as coastal protection, i.e. replanting mangrove and eucalyptus. Replanting mangroves also mean reintroducing sedimentation in the coastal zones. Incoming sedimentation from the upstream area is the part of a natural system where new sediments compensate the natural subsidence (Ingebritsen & Galloway, 2014). In the recent years, large dam installations in the upstream area of Mekong worsen the subsidence rate in the coastal region due to the lowering aggradation (MRC, n.d.; Tri et al., 2016). Mangrove layer used to prevent inland salt water intrusion, but the rising sea level asserted the existence of these natural protections (MRC, n.d.). Mangrove restoration could assist dynamic sedimentation which possibly lessens the investment cost for coastal protection (MDP, 2013). Deltares and Wetlands International conducted a pilot project on mangrove restoration on the north Java coast, Indonesia, which one of the functions meant to retain sediment (Deltares, 2014). Hence, further research is needed to understand the efficiency of mangrove layer as coastal protection in the VMD (E. Sutanudjaja, personal communication, January 6, 2017). Meanwhile, in the urban sector, Minderhoud et al. (2015) proposed the trend of using lighter building materials for the future development to abate loading stress above the ground.

Installing Hard Options The adaptive management practices often resort to the development of hard infrastructures. This decision becomes compulsory to complement the soft option measures. For land subsidence and saltwater intrusion issues, hard options sometimes come in the form of building protection structures in the coastal zone or constructing a new water supply system (Hanson, 2015; Smajgl et al., 2015). Most of the coastal zones in the delta regions have a sea dikes system that protects the inland area from saltwater intrusion. Besides the dikes system, the agriculture sector in the VMD floodplain utilizes sluice gates and other hard infrastructure to regulate the irrigation water quality for their fields (Thanh, 2016). Currently, the VMD sea dikes layer is in need of refurbishment to prevent further intrusion and improve delta safety which sustained the economic development (MDP, 2013). In another practice, Santa Clara Valley in California, USA, had succeeded to rejuvenate their groundwater system by applying conservation, artificial recharge, and importing water from other regions (Hanson, 2015). Extensive pipeline network and diversion facilities deliver high-quality surface water from the Sierra Nevada range (Ingebritsen & Galloway, 2014).


14

It is important to mention that hard measure usually comes from developed countries. To implement such measures with high financial requirement might be more difficult for developing countries which need to search for grant or loan. Instead, local coastal protections (e.g. mangrove layer) offer technical and economic feasibility for delta regions in developing countries. However, for a long-term objective, such extensive perimeters for VMD are deemed more defensible (Ingebritsen & Galloway, 2014). Since land subsidence and saltwater intrusion are unlikely to be completely stopped in the near future, a lifetime investment to secure the delta life in the form of coastal protection is needed. Beside sea wall enhancement, closing the estuary has the effect of reducing saline intrusion both in groundwater and surface water (MDP, 2013). As proposed by the Mekong Delta Plan, the Vietnamese government has prepared a plan to close some of the nine estuaries of The Mekong River, but elaborated study on how it will affect the shipping activities are not completed yet (R. Dam, personal communication, January 13, 2017).

3.2. Critical Conditions for Successful Measure Implementation Each proposed measure in the previous section is accompanied by prerequisites that need to be attained for its feasibility. Although there are different requirements for different measures, some of them are recurring. In this section, these frequent dimensions will be called as „critical conditions‟ due to its significance for an effective measure implementation. These conditions are divided into technical and institutional requirements. Table 3 and 4 below summarize the recurrent critical dimensions and identify its relevance for each proposed measure. If a measure scores high (very relevant) in many conditions, it means that the application of the measure requires more efforts for a fruitful result. This overview allows the interested parties in the VMD to compare and select suitable measures according to their capabilities. Technical Critical Conditions Due to the wide range of options and its literature, there is a need to present an overview of recurrent challenges to support the coordination and decision making by the future practitioners (Dieperink et al., 2016). This study identifies four critical conditions that are frequently mentioned in the used literature. In details, one measure may demand different treatment to another. For example, artificial recharge requires detailed knowledge about the local subsurface structure and its hydraulic characteristics (Vuong et al., 2015) while household RWH calls for an understanding of the local climate and roof selection (Farreny et al., 2011). These two seemingly different conditions can be categorized into one dimension called prior knowledge which describes the required learning before implementing the measure. Freshwater variability depicts whether one measure depends on the existence of a diverse water resources other than groundwater. The difficulty level of utilizing the method is covered in installation technology where from a technical perspective, limiting groundwater abstraction or fixing water leakage are easier compared to building a new WWTP. Maintenance effort illustrates the degree of required technical keep up to ensure the measure‟s efficiency. The critical condition detail of the measures can be found in their explanation in the previous section. Table 3 An overview of technical critical conditions for each proposed measure

Measure Limitation of groundwater abstraction Pumping tax Building water treatment plant Fixing water leakage Artificial aquifer storage Riverbank infiltration and/or infiltration basin Rainwater harvesting Remapping the land use planning Sea dikes Extensive water infrastructure

Prior Knowledge

Technical Requirement Freshwater Installation Variability Technology

Maintenance Effort

+

+++

-

-

+ + + ++

+++ + ++

++ ++

++ +++ ++

++

++

++

++

+ +++ +++ +++

+ +

++ +++ +++

++ + +++ +++

Note: - not relevant, + moderately relevant, ++ relevant, +++ very relevant


15

Despite the selected dimensions, there is a need to conduct a constant monitoring of the actual land subsidence rate. It helps the accuracy of the calculation of potential subsidence rate in the future (Minderhoud et al., 2015). Table 3 shows that extensive water infrastructure comes as the most technically complicated measure for coping with land subsidence and saltwater intrusion. As it is illustrated with Santa Clara Valley California study case, building major hard infrastructure such as a long pipeline to import high-quality water requires much technical proficiency from the planning to the maintenance. Meanwhile, charging a pumping tax appears to be the simplest one due to its directness for targeting groundwater user. Both prior knowledge and maintenance effort scored as relevant in almost all the proposed measures. In any project implementation, feasibility studies are indeed necessary to investigate the appropriateness of the measures. The relevancy in Table 3 shows the difference in the familiarity and complexity of the measure among the practitioners in the VMD. In one side, relatively new technologies in the VMD such as artificial storage and riverbank infiltration were given (++) due to its intricate prerequisite compare to RWH which is simpler. In the other side, spatial planning and sea dikes practices are well-known in the VMD, these measures are given (+++) because of their complicated planning. Similar reasoning applies for scoring in maintenance effort where it is irrelevant for limiting groundwater abstraction and pumping tax measures. Principally, any measures would need a good maintenance for its longevity, but in this specific term, the maintenance refers to the technical support. Hence, the first two measures are exempted from this necessity.

Institutional Critical Conditions The case of Jakarta and Bangkok showed that even with the straightforward technical condition, one measure could face more difficulties during implementation. This relates to the social-institutional aspect that governs the likeness of successful practice in one area. On the one hand, a fruitful outcome needs rightful regulations along with an orderly and clear division of responsibility in various levels within the government. An adequate governance system has to be present particularly in a wide scale implementation (Tri et al., 2016). On the other hand, the household behavior is on the same level of importance as they usually are the target or directly impacted by the implementation effort. Any initiatives that deemed as antagonistic towards household might weaken the implementation effectiveness (Smajgl et al., 2015). Both governance and household aspects are covered in the six dimensions on Table 4 below. It displays institutional requirements that derived from the ACW method proposed by Gupta et al. (2010). Since land subsidence and saltwater intrusion compel the society to have an adaptive trait, ACW can be used as a tool to assist both researchers and policymakers in evaluating the state of institutional capability to encourage the adaptive capacity. An institution covers not only organization as in this case is „the government‟ but also the ideological values and norms (ibid). These ideal institutions have attributes that 1) endorse varied perspectives, actors, and solutions (variety), 2) allow the social actor to improve (learning capacity) and 3) adapt their behaviour (room for autonomous change); 4) encourage leader qualities (leadership); 5) manage responsibly the financial, human, and decision-making resources (resource availability), and 6) support legitimate, equal, responsive, and accountable governance (fair governance) (Gupta et al., 2010; Gupta et al., 2015). In a highly adaptive society, such measures are assumed to be well accepted while at the same time, it is normally hard to find an institution that provides the whole six dimensions. Table 4 displays the requirement relativeness of one measure toward each dimension. Table 4 An overview of institutional critical conditions for each proposed measure

Measure Limitation of groundwater abstraction Pumping tax Building water treatment plant Fixing water leakage

Institutional Requirement Room for Leader Resource Autonomous -ship Availability Change

Variety

Learning Capacity

Fair Governance

+++

++

-

+

+++

+++

+++

++

-

+

+++

+++

++

+

-

++

+++

+

++

++

++

+

++

++


16

Artificial aquifer storage Riverbank infiltration and/or infiltration basin Rainwater harvesting Remapping the land use planning Sea dikes Extensive water infrastructure

++

-

-

-

++

+ +

++

-

-

-

++

++

++

++

+

++

+

+++

++

++

+++

+++

+++

+++

-

-

++

+++

+++

+++

-

-

++

+++

++

Note: - not relevant, + moderately relevant, ++ relevant, +++ very relevant Determining relevancy of each institutional dimension for the nine measure groups are more complicated than the technical one. In most literature, technical know-hows are clearly written while the recognition of institutional aspects requires other in-depth studies. Table 4 describes remapping land use planning as the measures which need the most concern from the institutional point view. Changing one area‟s spatial planning requires an extensive effort to connect all the stakeholders which should result in fair planning for its population. Thus, the six institutional critical conditions are relevant for that measure. Room for autonomous change scored as not relevant except in those measures which require the institutions to adapt and improvise during the implementation of the measures. Most of the measures above are predefined and rigid. For example, pumping tax would have clear and stringent rules while sea dikes would have a fixed design which cannot be altered by the institutions. Meanwhile, artificial aquifer storage and riverbank infiltration are installed under the circumstances where it requires no adaptation from the adjacent environment. Among the six critical conditions, variety, resource availability, and fair governance dominate the requirement for all measures. It shows that all the proposed measures appeal to the contribution of various stakeholders, sufficient resource (both human and financial), and supportive governance.

3.3. The Current VMD Status After listing out the relevancy of the critical conditions in all measures, a further assessment is needed to check whether these conditions are existed in the present VMD, particularly in the Soc Trang Province. Table 5 summarizes the assessment result of the current critical conditions in the VMD which shows that the delta possesses sufficient critical conditions for the implementation of some proposed measures. Table 5 The Summary of the ten critical conditions‟ presence in the VMD

Technical Critical Conditions Prior knowledge Freshwater variability

Institutional Critical Conditions ++ Variability Learning Capacity + Room for Autonomous Installation technology Change Maintenance effort Leadership Resource Availability Fair Governance Note: - non-existent, + rising trend in the existence, ++ existent Presence

Presence ++ + ++ + -

Prior Knowledge The Vietnamese government is aware of the water system knowledge and the impending threat in their area (Tri et al., 2016). The official of Soc Trang Province published a guideline to protect water resources and avoid negative impact of saline intrusion by regulating the groundwater abstraction, collecting rainwater, shifting to surface water for domestic water use, transferring water from groundwater-rich aquifer to limited one, investing in water-saving technology, and developing new crop varieties (Thanh, 2016). Historically, the indigenous VMD population (Khmer people) used to practice their extensive local wisdom to manage the land use planning in the area. When the population from the northern region of the Vietnam (Kinh people) came and occupied the delta, canals Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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were built to regulate the water in the delta (J. Kleinen, personal communication, January 13, 2017). In general, both government and society possess an adequate level of water management‟s basic understanding. While Table 2 shows recent aquifer states under the VMD, the detail in the provincial resolution is not well monitored. Water-related data availability in the Vietnam is either lacking or unstructured (P. Minderhoud, personal communication, January 24, 2017). While the DONRE in each province is responsible for data collection and monitoring, the Soc Trang‟s DONRE has limited knowledge and data about the detailed aquifer system at the province level (Tri et al., 2013). The latest available data of Soc Trang‟s groundwater reserves are measured in 2010 (Thanh, 2016). At the same time, improvements are needed to support the implementation of proposed measures. The national government had acquired the technical proficiency for some measures (e.g. building WWTPs, sea dikes, fixing leakage) whereas new methods such as RWH and ASR are still on the preliminary study and pilot projects phases (Thanh, 2016; Wilbers et al., 2013). Freshwater Variability The groundwater state in the Soc Trang Province is not constantly monitored yet the agriculture and aquaculture practices in the province had been using groundwater since around twenty-five years ago (P. Minderhoud, personal communication, January 24, 2017; R. Dam, personal communication, January 13, 2017). Many households in Soc Trang depend on their pumping wells, where there were 2 at least 24 groundwater wells per km in 2010 (Thanh, 2016). Surface water (Hau, My Thanh, and Quan Lo Rivers) used to be the main water reserves for drinking and domestic purpose, but it became polluted due to the rapid urbanization alongside river and canals (ibid). Besides pollution, the river and canal networks in the VMD are very vulnerable toward saline intrusion. The highest salinity occurs at the end of the dry season, usually in April or in early May during late-raining years (Vuong et al., 2015). As for the precipitation rate, the VMD has an annual average rainfall of 1660 mm (Wilbers et al., 2013) where 95% of these precipitations fall between May and November (Thanh, 2016). The excess water during the rainy season is naturally stored in the paddy fields or discharged directly to the rivers (P. Minderhoud, personal communication, January 24, 2017). In the present days, the problem with surface water in the VMD is related to the water quality. Theoretically, the discharge rate of Mekong River network is sufficient to supply the VMD‟s water demand, even with upstream damming (R. Dam, personal communication, January 13, 2017; E. Sutanudjaja, personal communication, January 6, 2017). Installation Technology As mentioned in the prior knowledge, the VMD had the experienced to implement some of the proposed measures. The most relevant, thus complex, installation technology belongs to both sea dikes and extensive water infrastructure. The current VMD has a dike system which is deemed too low while the sea level rises keep reinforcing (MDP, 2013). The Soc Trang Province has a 93,8 km sea dike which is a part of structural measures alongside river dikes and sluice gates to regulate the saline intrusion (Thanh, 2016). Meanwhile, the water infrastructure in the VMD has a low coverage in general. Other measures such as ASR and riverbank infiltration are quite new in the delta. An experiment of aquifer recharge in the central Vietnam had been tested, but the cost of this trial was too high for other replications (ibid). This might be due to the VMD‟s subsurface character where a thick clay layer is present at the top (P. Minderhoud, personal communication, January 24, 2017). RWH pilot projects had been applied in three provinces of the VMD (i.e. Can Tho, Hau Giang, and Soc Trang) where the houses use concrete/asbestos tiles, thatch, and galvanized metal roofs with gutters connected to clay or concrete jars for storage (Wilbers et al., 2013). With many international joints work on the delta, the knowledge and technology transfers for various measures are expected to spread among the practitioners in the VMD. Maintenance Effort Almost every recommended measure above needs a technical maintenance to assure its longevity. As written in the installation technology section, the VMD‟s current capability for preserving their infrastructure is moderately low. The DARDs in the provincial level govern the operation and maintenance of the main irrigation and disaster prevention infrastructures. The residents are involved in the irrigation‟s maintenance by hiring a contractor and share its cost among them (Thanh, 2016). As for the hard infrastructure‟s maintenance, the states of some flood defense structures in the VMD vary from an excellent to a terrible condition (MDP, 2013). Measures like ASR, SWT, and riverbank infiltration require a higher level of expertise to maintain the operation of the well system. Most of the Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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problems with the maintenance in the VMD stem down to the resource management, which will be mentioned in the resource availability below. Variety In the delta level, the VMD had involved in many international projects particularly relates to climate change resilience. In June 2016, the World Bank and the Ministry of Natural Resources and Environment (MONRE) of Vietnam signed a project titled Mekong Delta Integrated Climate Resilience and Sustainable Livelihoods Project for Vietnam that would be carried out in selected province in the delta. The objectives of this project include addressing the groundwater management and salinity challenge in the coastal provinces (The World Bank, n.d.). To some extent, the Mekong Delta Plan (2013) is used as the base for the World Bank project‟s working design (R. Dam, personal communication, January 13, 2017). Furthermore, Thanh (2016) presents a list of projects that being implemented in Soc Trang with various partnerships between the ministries and foreign institutions (NWO, Deltares, German International Cooperation-GIZ, Australian Aid-AUSAID, Japan International Cooperation Agency-JICA, VEI, etc). The Vietnamese elect their representatives in the executive bodies at the various level of governance, i.e. People‟s Committee in the provincial, district, and communal level. The Ministry of Agriculture and Rural Development (MARD) and MONRE usually cooperate with the People‟s Committee for imposing and monitoring water-related regulations in the smaller scale. In the meantime, public participation in the freshwater management of the delta is limited due to the weak vertical and horizontal integration. Whereas in Soc Trang, the level of involvement is almost absent (ibid). The mediator roles which usually performed by Non-governmental Organizations (NGOs) are restricted and rather unique in the VMD. The movement of local NGOs is suppressed by the government while international NGOs are controlled by the government due to their infamous propaganda of selling „peaceful coexistent‟ (between socialist and other ideology) in the past time (J. Kleinen, personal communication, January 13, 2017). Learning Capacity The Socialist Republic of Vietnam is a socialist country with a single ruling party which is, the Communist Party of Vietnam (CPV). The long history of Vietnam with various influences from Chinese communist, the French Colonization, and the division of the northern and southern part of the country in 1954 shaped the Vietnam today (J. Kleinen, personal communication, January 13, 2017). The current governance of the VMD rules with a top-down hierarchical system and strict control (Thanh 2016). The data and information sharing among the state institutions is quite weak, in particular in its vertical linkage. In the Soc Trang Province, the exchange of information is not regulated in a clear framework. The functions delegation from the upper to lower level of government is also limited where it gave fewer authorities and responsibilities in the district and commune level. Meanwhile, non-state actors such as farmers and local water users are given the opportunities to be involved in the study for water-related policy making (ibid). In general, the government of the VMD has the intention to build mutual trust among different level and toward the public. However, this has not been practiced in their learning routine. The VMD managers had incorporated uncertainties to their regulation and policy by making climate change and sea level scenarios although the practice is rather vague. Room for Autonomous Change Since the Vietnam is known for its top-down approach, room for improvisation within its state institutions is limited by the central government‟s decision (Thanh, 2016). In the lower (e.g. province) level, the state‟s initiatives are usually bounded by the administrative border. For example, the DONREs cannot improvise to import freshwater from WWTPs in the other provinces to provide freshwater. Hence, the provincial authority usually focuses on working the work on their area (P. Minderhoud, personal communication, January 24, 2017). The public initiatives are hindered by the complicated relationship between the government and the local population. As for instance, the Soc Trang‟s authority is trying to enforce groundwater management‟s regulations through the intervention of the water supply company. Although some of the local groups (e.g. farmers) are involved in the policy making, their opinions are less accommodated for project‟s implementation since they are deemed to not have technical knowledge. The locals admit that the authority never even asked for an opinion during the project planning (Tri et al., 2016). They are also currently not engaging in the management activities since they believe that it should be the government‟s responsibility (ibid). The VMD‟s inhabitants are known for their ability to Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

19

stand the coercion that stems from the top down approach of the socialist country. Nevertheless, they also have the will to manage their lives as goes by an old saying that more or less means, the law of the emperor stops at the gate of the village (J. Kleinen, personal communication, January 13, 2017). Leadership As mentioned in the variety, many international projects are currently planned, initiated, or implemented in the VMD. Most of the projects in the Soc Trang Province are focused on the coastal development and water management in the rural areas, with the MARD and MONRE as the organizer and implementer of these projects (Thanh, 2016). The research institutes in the delta, such as Can Tho University, are expected to be the network hub among international and domestic actors which deliver a long-term vision for the delta (ibid). The Vietnamese have the tendency to „shop around‟ and compare the price to make the project delivery favourable (J. Kleinen, personal communication, January 13, 2017) which brings more opportunity for collaborations in the future. Resource Availability The international projects in the VMD ordinarily offer financial support which should be managed by the implementing agencies. One of the most recent approved projects, Mekong Delta Integrated Climate Resilience and Sustainable Livelihoods Project of The World Bank, grants a total commitment fund of US$ 310.00 million to the MONRE (The World Bank, n.d.). Due to this extensive responsibility and authority, the MONRE is expected to have adequate human resources for the management purpose. This ministry consists of at least 35% masters and PhD graduated staff whereas the DONREs have around 1% of the BA/BSc graduated staffs although the soft and management skills among them are rather neglected (MDP, 2013). This skilled manpower is not equally distributed where most of them concentrated in the province capital. Fair Governance The definition of fair governance in the Vietnam might be different in the other countries, due to its socialist ideology. While the ACW‟s fair governance asks for legitimacy and equity where the public support and consider that the institutional rules to be fair, the Vietnamese has the character to mimic the power holder and the practice of having under the table agreement (J. Kleinen, personal communication, January 13, 2017). At the same time, the Vietnamese government is comparatively responsive due to the excellent communication with socialist-style public address (PA) system which made them easier to address the people (ibid). However, there is a lack of coherence in the government system. Currently, the DONRE (under MONRE) governs the groundwater management while the DARD (under MARD) is in charge of managing rural supply (Tri et al., 2016). These seemingly overlapping tasks cause confusion for the public and resulting in low level of regulation compliance, especially in the lower level target (i.e. village).

4.

Discussion

Determining the most feasible measure among the proposed measures requires many considerations in which represented by the critical conditions. By weighting the presence of the critical conditions in the delta, the proposed measures above can be evaluated whether it is feasible to be implemented. In the present time, most of these critical conditions are either rising in the trend or already existing. However, these assessment results are more lenient due to the research limitations. Since most of the critical conditions above are in middle of a transformation, little change from both internal and external factors will significantly affect the implementation process. Hence, there is no fixed division between feasible and not feasible measures. To accommodate this, the proposed measures above are distributed into a short term and long term. The most straightforward solution to tackle land subsidence and saltwater intrusion issues is by limiting, or rather, stopping groundwater use (R. Dam, personal communication, January 13, 2017). Although it is possible, most of the succeeded areas (e.g. Tokyo, Venice, and The Netherlands) required years to shift their main water resource from groundwater (E. Sutanudjaja, personal communication, January 6, 2017). Theoretically, the ten critical conditions in this report would have to be presented in the delta. The short-term measures can be taken with the current existing critical conditions. With the absence of two technical critical conditions, freshwater variability and maintenance effort, the proposed measures which depend on the availability of other water reserves and maintenance effort could not be implemented immediately. In the present time, chances to Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

20

Comment [CD1]: ?

implement short-term measures are supported by the rising awareness in government toward environment value and the imminent threat caused by both land subsidence and saltwater intrusion. Further opportunity comes in the form of various studies and projects (mostly are international initiation) which also provide financial resources for the freshwater management. Nevertheless, the rigid governance system and inadequate communication among the state institutions, as well as between the government and the delta‟s inhabitants, might hamper the effort to attain a successful implementation. The external threat might appear from the upstream countries within the Mekong River Basin. The differences in managing the freshwater management might disrupt the river water quality which also hampers the VMD‟s attempt to shift the main water supply. With the similar reason, another possible threat comes from the big industries within the delta. In the long run, an integrated planning for the delta resilience toward the changing environment needs to be planned. Such spatial planning acts as a preventive solution for further negative impacts (E. Saputra, personal communication, January 12, 2017). As land subsidence especially increases the flood risk for a region, the counter-measures should also address flood water management while at the same time should accommodate the needs of its inhabitants. The government should also consider and invest in the hard infrastructures, particularly for coastal protection (R. Dam, personal communication, January 13, 2017), since land subsidence and saltwater intrusion are more likely to continue in the future. This corresponds with the mindset of the Vietnamese, conquering the land from the sea, where they believe that nature (esp. water/sea) is stronger and can be dangerous thus could be their enemy sometimes (J. Kleinen, personal communication, January 13, 2017). At the same time, the recent concept of building with nature accommodates the way of living „with‟ water, not „against‟ it. In the Vietnam, this new design might not be well accepted due to their mindset, but the attitude to adapt with nature (e.g. floating house in the Netherland) is agreeable. This idea is important to understand that any project is needed to be accepted and tailored to the public. To achieve this long-term objective, the current state of the institutional critical conditions in the VMD should be improved. The VMD government should challenge to do the double loop learning, where they have to challenge the existing norms and the underlying assumption that prevail in the country. When the state institutions succeed to adopt the learning capacity into the practice, it is expected that fair governance will also present in the delta. In the current VMD, the MONRE had performed the leader role for managing the freshwater resource. The MONRE had proved to be aware of both land subsidence and saltwater intrusion issues while at the same time had received most of the financial aid from the national and international cooperation. These available resources should be managed to encourage the short term measures as their priority while simultaneously investing in the long term solutions. A limitation of this study is that no ground observation was made for the delta assessment. The appraisal source for the VMD came from the literature review where Thanh (2016) and Tri et al. (2016) offer a broad range of information related to the freshwater management in the VMD. Besides, the five interviews provide an in-depth understanding of the background knowledge that prevails in the delta. Since this report will serve as an additional input during the Rise and Fall project workshop, a cross-check study should be able to ensure whether the assessment is accurate.

5.

Conclusion

Although the issue of land subsidence and saltwater intrusion are relatively new compared to other water management problems, a broad range of solutions had emerged as the responses. These solutions are categorized into four groups of measures, i.e. reducing pressure for groundwater abstraction, expanding the source of water supply, managing the existing land use, and installing hard options. Each measure has both the technical and institutional critical conditions which ensure a successful implementation. The technical conditions include prior knowledge, freshwater variability, installation technology, and maintenance effort whereas the institutional prerequisites cover variety, learning capacity, room for autonomous change, leadership, resource availability, and fair governance. In the current VMD, these critical conditions are mostly rising in trends or wholly present, except for freshwater variability, maintenance effort, learning capacity, and fair governance. By relating the critical conditions of the measures and their presences in the VMD, fixing water leakage and RWH can be proposed as the most feasible measures for coping with land subsidence Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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and saltwater intrusion in the VMD. These two measures are short-term options those are viable to be implemented immediately. Fixing leakage in the existing water supply system supports the idea of efficient use water while groundwater abstracted is limited and other water resources are not yet reliable. In the present VMD, the resources are available to implement this measure as long as its operation is well monitored. Correspondingly, RWH addresses the tendency of the Vietnamese population for being autonomous. With adequate knowledge in the rainfall pattern and simple technology, this measure is rather feasible to be implemented at the village level. The main focus to carry out this measure is finding the most efficient way to facilitate the installation method for each household considering that communicating with the inhabitant of the VMD require particular approach. The other proposed measures are either limited by the freshwater resource variability, difficult technology, and unreliable government capacity. Hence, options such as integrated spatial planning and investing in the hard structures for coastal protection are more suitable as the longer term solutions considering they are significant to promote the future resilience of the delta. In general, there is no „one-size-fits-all‟ solution for all. Such tailored approaches are needed, and a willingness to invest in the future of an area is essential.

6. References Agence Française de Développement (AFD). 2014. Clean Water Project in Mekong Delta Cities. Retrieved from http://www.afd.fr/lang/en/home/pays/asie/geo-asie/afd-vietnam/cac-du-an-cuaafd-tai-viet-nam/phat-trien-o-thi/du-an-nuoc-sach-o-cac-thanh-pho-vung-ong-bang-song-cuulong (12 Dec 2016). Anh, P. T., Kroeze, C., Bush, S. R., & Mol, A. P. (2010). Water pollution by Pangasius production in the Mekong Delta, Vietnam: causes and options for control. Aquaculture Research, 42(1), 108-128. Baguma, D., Loiskandl, W., & Jung, H. (2010). Water management, rainwater harvesting and predictive variables in rural households. Water Resources Management, 24(13), 3333-3348. (DAFWA) Department of Agriculture and Food Western Australia. (2016). Stormwater reuse project. Retrieved from https://www.agric.wa.gov.au/climate-change/stormwater-reuseproject?nopaging=1 (12 January 2017). Deltares. 2014. Dutch ‘Building with Nature’ approach used in coastal recovery for Java and Bali. Retrieved from https://www.deltares.nl/en/news/dutch-building-nature-approach-used-coastalrecovery-java-bali/ (15 January 2017). Dieperink, C., Hegger, D. T., Bakker, M. H. N., Kundzewicz, Z. W., Green, C., & Driessen, P. P. J. (2016). Recurrent Governance Challenges in the Implementation and Alignment of Flood Risk Management Strategies: a Review. Water Resources Management, 30(13), 4467-4481. (DWS) Dutch Water Sector. (2015). Dutch consortium investigates potential of Balance Island concept for deltas of Bangladesh and Vietnam. Retrieved from http://www.dutchwatersector.com/news-events/news/13186-dutch-consortium-investigatespotential-of-balance-island-concept-for-deltas-of.html (12 January 2017). Endo, T. (2011). Sinking cities and governmental action: institutional responses to land subsidence in Osaka and Bangkok. In Groundwater and Subsurface Environments (pp. 271-288). Springer Japan. Erban, L. E., Gorelick, S. M., & Zebker, H. A. (2014). Groundwater extraction, land subsidence, and sea-level rise in the Mekong Delta, Vietnam. Environmental Research Letters, 9(8), 084010. Erkens, G., Bucx, T., Dam, R., De Lange, G., & Lambert, J. (2015). Sinking coastal cities. Proceedings of the International Association of Hydrological Sciences, 372, 189. Faneca Sanchez, M., Bashar, K., Janssen, G.M.C.M., Vogels, M., Snel, J., Zhou, Y., Stuurman, R. and Dude Essink, G.H.P. (2015). SWIBANGLA: Managing salt water intrusion impacts in coastal groundwater systems of Bangladesh, p.153. Farreny, R., Morales-Pinzón, T., Guisasola, A., Taya, C., Rieradevall, J., & Gabarrell, X. (2011). Roof selection for rainwater harvesting: quantity and quality assessments in Spain. Water Research, 45(10), 3245-3254. Future Delta. (n.d.). Project: Rise and Fall. Retrieved from https://www.uu.nl/en/futuredeltas/projectrise-and-fall (20 November 2016). Gallego-Ayala, J., & Juízo, D. (2011). Strategic implementation of integrated water resources management in Mozambique: An A‟WOT analysis. Physics and Chemistry of the Earth, Parts A/B/C, 36(14), 1103-1111. Galloway, D. L., & Burbey, T. J. (2011). Review: regional land subsidence accompanying groundwater extraction. Hydrogeology Journal, 19(8), 1459-1486. Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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Gupta, J., Termeer, C., Klostermann, J., Meijerink, S., van den Brink, M., Jong, P., ... & Bergsma, E. (2010). The adaptive capacity wheel: a method to assess the inherent characteristics of institutions to enable the adaptive capacity of society. Environmental Science & Policy, 13(6), 459-471. Gupta, J., Bergsma, E., Termeer, C. J. A. M., Biesbroek, G. R., van den Brink, M., Jong, P., ... & Nooteboom, S. (2015). The adaptive capacity of institutions in the spatial planning, water, agriculture and nature sectors in the Netherlands. Mitigation and Adaptation Strategies for Global Change, 1-21. Hanson, R. T. (2015). Hydrologic framework of the Santa Clara Valley, California. Geosphere, 11(3), 606-637. Ingebritsen, S. E., & Galloway, D. L. (2014). Coastal subsidence and relative sea level rise. Environmental Research Letters, 9(9), 091002. IUCN. (2011). Groundwater in the Mekong Delta. Retrieved from https://cmsdata.iucn.org/downloads/iucn___groundwater_in_mekong_delta_25_may_11_w.p df (21 November 2016. Kaneko, S., & Toyota, T. (2011). Long-term urbanization and land subsidence in Asian Megacities: An indicators system approach. In Groundwater and Subsurface Environments (pp. 249-270). Springer Japan. Kleinen, J. (2015). Vietnam: One-Party State and the Mimicry of Civil Society. Retrieved from http://www.irasec.com/ouvrage122 Maliva, R., & Missimer, T. (2012). Managed aquifer recharge. In Arid Lands Water Evaluation and Management (pp. 559-630). Springer Berlin Heidelberg. (MDP) Mekong Delta Plan. (2013). Mekong Delta Plan: Long-term vision and strategy for a prosperous and sustainable delta. Retrieved from https://www.wur.nl/upload_mm/2/c/3/b5f2e669-cb48-4ed7-afb6-682f5216fe7d_mekong.pdf (22 November 2016). Minderhoud, P. S. J., Erkens, G., Pham, V. H., Vuong, B. T., & Stouthamer, E. (2015). Assessing the potential of the multi-aquifer subsurface of the Mekong Delta (Vietnam) for land subsidence due to groundwater extraction. Proceedings of the International Association of Hydrological Sciences, 372, 73. (MRC) Mekong River Commission. (n.d.). Living on the edge of the rising sea. Retrieved from http://www.mrcmekong.org/mekong-basin/stories-from-the-mekong/living-on-the-edge-of-therising-sea/ (19 December 2017). Pandey, D. N., Gupta, A. K., & Anderson, D. M. (2003). Rainwater harvesting as an adaptation to climate change. Current science, 85(1), 46-59. Reterrer, J.S. (2015). The Dawn of a New Era Groundwater Regulation in California http://www.lgattorneys.com/perch/resources/jsr-article-spinrg-2015-coastal-grower-00757175xbbe29-1.pdf 05 Dec 2016 Rise & Fall Project. (n.d.). Retrieved from http://rf.ctu.edu.vn/en/541/ (20 November 2016). Safavi, H. R., Darzi, F., & Mariño, M. A. (2010). Simulation-optimization modeling of conjunctive use of surface water and groundwater. Water resources management, 24(10), 1965-1988. Sato, X. C., Haga, M., & Nishio, J. (2006). Land subsidence and groundwater management in Tokyo. Internat Rev Environ Strat, 6(2), 403. Smajgl, A., Toan, T. Q., Nhan, D. K., Ward, J., Trung, N. H., Tri, L. Q., ... & Vu, P. T. (2015). Responding to rising sea levels in the Mekong Delta. Nature Climate Change, 5(2), 167-174. Stefan, C. (2014). Groundwater vulnerability in Vietnam and innovative solutions for sustainable exploitation. J. Viet. Env. 2014, Vol. 6, No. 1, pp. 13-21 DOI: 10.13141/jve.vol6.no1.pp13-21 Thanh, H.P. (2016). Into the unknown: an assessment of the freshwater governance regime in the Vietnam Mekong Delta in the context of climate change and rising sea level. (Unpublished master‟s thesis). Utrecht University, The Netherlands. The World Bank. (n.d.). Mekong Delta Integrated Climate Resilience and Sustainable Livelihoods Project. Retrieved from http://projects.worldbank.org/P153544?lang=en (20 January 2017). Tri, V.P.D, Dieperink, C., & Otter, H. (2016). Fit for the Future? An exploration of groundwater governance challenges in the Vietnamese Mekong Delta. (Unpublished report). Deliverable 3.1 for the “Rise and Fall” project. UNESCO. (n.d.). Managed Aquifer Recharge (MAR). Retrieved from https://www.un-igrac.org/areasexpertise/managed-aquifer-recharge-mar (12 Dec 2016).


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Van Manh, N., Dung, N. V., Hung, N. N., Kummu, M., Merz, B., & Apel, H. (2015). Future sediment dynamics in the Mekong Delta floodplains: Impacts of hydropower development, climate change and sea level rise. Global and Planetary Change, 127, 22-33. Vuong, B.T., Lam, D.T., & Van, L.T.M. (2015).Groundwater Issues and Hydrogeological Survey of the Mekong River Basin. In Vietnam in Current Status and Issues of Groundwater in the Mekong River Basin. Retrieved from http://unesdoc.unesco.org/images/0024/002436/243616E.pdf (21 November 2016). (WWI) Water and Wastewater International. (2012). Editorial Focus: Stormwater Management: A Shining Star in Rainwater Harvesting Volume 27, Issue 4 http://www.waterworld.com/articles/wwi/print/volume-27/issue-4/editorial-focus/stormwatermanagement/south-korea.html Wilbers, G. J., Sebesvari, Z., Rechenburg, A., & Renaud, F. G. (2013). Effects of local and spatial conditions on the quality of harvested rainwater in the Mekong Delta, Vietnam. Environmental pollution, 182, 225-232. Zuurbier, K. G., Raat, K. J., Paalman, M., Oosterhof, A. T., & Stuyfzand, P. J. (2016). How subsurface water technologies (SWT) can provide robust, effective, and cost-efficient solutions for freshwater Management in Coastal Zones. Water Resources Management, 1-17.

7.

Appendix

Detail on Interview Interviewee Date and time of interview Place of interview

: Erlis Saputra th : Thursday, January 12 2017, 15.10-16.15 : Unnik Building, Universiteit Utrecht

Questions: 1. Do you think land subsidence and saltwater intrusion is a significant threat in VMD? 2. To some extent, the cause of land subsidence in Jakarta and VMD is groundwater exploitation, do you agree? 3. What kind of measures had been implemented by Jakarta government about the ongoing land subsidence? 4. In your article, you focus on development planning and disaster management as the solution. Why is it so? 5. What institution is responsible for enforcing these measures? In Indonesia, is it BNPB (National Board for Disaster Management)? 6. In your article, NGOs are given an important role to actually engage the public. What kind of NGOs? Should it be some NGOs with a lot of local experience who are known already by the public? 7. What is participatory mapping? 8. In the present condition, what is the level of public participation in Jakarta? 9. Compare to the VMD's demographic, will your findings relatable there? 10. What do you think about the Adaptive Capacity Wheel (ACW)? Summary: The interview with Erlis Saputra began with introductory questions about his involvement in land subsidence related research. His encounter with land subsidence issue was mainly due to his interest to cities spatial planning. As a researcher in Human Geography department at Utrecht University, the focus on land subsidence is part of the feasibility study for a city planning. In Indonesia, the study of land subsidence still concentrates on the physical measurement. These practices are usually conducted in cooperation with UGM (Gadjah Mada University, Yogyakarta), ITB (Institute of Technology Bandung), Japanese universities, JICA (Japan International Cooperation Agency), GIZ (Germany), Deltares (Netherlands). Even for the measurement only, financial supports are needed because the measuring equipment (GPS geodetic) and its entire survey are rather expensive. To avoid high cost for measurement, local institutions are using satellite imagery for Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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modeling subsidence nowadays. Other aspects such as governance, economic, and management have not been fully explored. Indirectly, land subsidence is approached from land governance aspect which practically governed by urban spatial planning. Hence he wrote an article about public participation in the proceeding about sustainable megacities. Regarding the trigger of land subsidence and saltwater intrusion, he understood that groundwater abstraction significantly contributes to the issues, at least in Jakarta, Semarang, and Bandung. Different factors (e.g. sea level rise, natural compaction, and oxidation) affect the different area in Indonesia, where Jakarta may have groundwater exploitation as the most pressuring reason while northern Semarang has land reclamation that influences its subsidence rate due to increasing loading. In Jakarta, urbanization and urban development drive higher water use. Urbanization encourages higher water demand due to growing population while urban development converts more land into water intensive one. Saltwater intrusion advances further into Semarang‟s inland area due to the new development in the reclaimed area. These new buildings push incoming tidal flood further inland as they act as a disturbance. Consequently, the inundation area of this saline water gets wider as well as the saltwater intrusion effect. He viewed that some of the mentioned factors are present in the Vietnam Mekong Delta, especially with the groundwater exploitation. For a long term solution, land use management is critical to address land subsidence problem. Hard infrastructures are urgent as curative measures, but at the end, spatial planning holds an integrated preventive solution to prevent further negative impact. In Indonesia, the most advanced region with its detail urban planning is Jakarta Province (detailed planning, smaller spatial resolution). Since 2013-2014 (during Jokowi-Ahok function), the BAPPEDA (Province Development Planning Board) of DKI Jakarta have addressed land subsidence as one of the main consideration for detailed zoning plan, RDTR (Rencana Detail Tata Ruang, Detailed Land Use Plan). For example, if it is known that 30% of the area is affected by land subsidence then the available area for „development.' Detailed zoning in Jakarta is legitimized as regional regulations with a fine sanction for such violation. Many regions in Indonesia are not fully aware of the threat of land subsidence and saltwater intrusion. Jakarta and Semarang, however, have realized the importance to monitor both land subsidence and groundwater state in their area. BPSDA (Water Resource Management Board) in DKI Jakarta governs the application of groundwater modeling that directly linked to land subsidence rate. This model informs the subsidence rate as the consequence of groundwater abstraction. Meanwhile, Semarang‟s BPSDA creates groundwater zoning that regulates the shallow aquifer for household water demand and deep aquifer for industrial use. In another act, Ministry of Environment and Forestry is now calculating the cost of environmental service between the upstream and downstream area in Ciliwung Basin. This is related to the surface water (river) quality which supposed to be the main water resource for the area. In short, some government boards in Indonesia have partially accommodated the issue, but larger and comprehensive efforts are of course still needed. In Indonesia, NGOs have the role in reaching the public. Depending on the type of NGOs, they have different approaches in connecting the government and the public. An international NGO usually conducts technical, feasibility, and/or policy study (e.g. how to carry out a good relocation, how to build a suitable canal) related to the issues while national NGO advocates to the local governments and ministries or carry out an impact study of land subsidence toward communities. Meanwhile, direct engagement with the local public is done by local NGOs. They also perform empowerment to improve adaptive capacity for the communities. For example, one local NGO in Semarang shares technology with the adjacent local to filter saline water into potable one. In recent years, NGOs roles are more impactful due to the support from the government. More and more regional conservation agencies (under government officials) are led by ex-NGO activists. It makes current NGOs access to speak with the government easier. In practice, local NGOs are used to approach the local community. Sometimes locals hold their own wisdom regarding many things, including how to deal with land subsidence issue. In the northern part of Jakarta, the local community knows how to measure the land subsidence rate because they elevate the houses 60 cm/5 years. This idea is practiced based on their experience living in the area for a long time. (Additional information: they only raise the building/land floor in their private land, if it is on public/government land, they will likely buy a pump during flood). NGOs can use a participatory


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mapping to categorize the issues in one area and connect the researcher (interested parties) knowledge and the local opinion into the picture (to bring their perspective in). NGO approach in Indonesia has its ups and downs as they usually produce creative ideas that address one issue but, at the same time, (some) government has such negative stigma toward them and unable to accommodate these fresh ideas (government agencies are commonly limited by financial budget). Moreover, these NGOs role is rather insignificant because it only covers a small area where land subsidence usually occurs in wider context. However, Erlis said that NGOs roles might not be needed in Vietnam. In his view, as a socialist country, the Vietnamese government can impose their plan (including measures to address land subsidence and saltwater intrusion) to the public without a lot of repulsions. Measures such as mangrove planting in the northern Semarang‟s coastal area is deemed as less effective because mangrove‟s roots grow 2 cm/year while the combination of coastal land subsidence and sea level rise over there are 15 cm/year. In Jakarta, artificial recharge was tested in three areas, but it had no followed ups. In the meantime, the percentage of connected buildings, both from household and industry sector, to water supply system is quite low. While 40% houses in Jakarta are connected to PDAM (Drinking Water Regional Company) system, only 20% of the industrial complex are connected. It is important to mention that some of these industries are water intensive. Meanwhile, Semarang city government gave subsidies to change building materials into a lighter one. Due to similar physical and social-demographic characteristic between Jakarta-Semarang and the VMD, some learning points that can be inferred. As mentioned, NGOs roles maybe not significant in the VMD because their government can put more pressure that makes the public receive the (planned) programs quite well. From an economical aspect, the government needs to give attention to public occupations if they want to relocate or do whatever related to displacing local community. The promised (new) location for the public should guarantee at least primary needs of the people.

Interviewee Date and time of interview Place of interview

: Rien Dam th : Friday, January 13 2017; 15.10-16.00 : Amsterdam CS

Questions: 1. Do you agree if the main reason for land subsidence and saltwater intrusion in the VMD is groundwater exploitation? 2. What is the current state of VMD's aquifer? You were involved in the VMD's groundwater modeling (2013), is it now being used by water managers in the region? 3. What about the surface water in the VMD? 4. How about other water resources alternatives? (ex. rain harvesting) 5. How are the opportunities of rain harvesting, artificial recharge, and riverbank infiltration in the VMD? 6. What are the primary factors that needed to avoid worse land subsidence rate and saltwater intrusion? 7. From your experience, what are the best measures for coping with land subsidence and salt water intrusion in the VMD? Will it be more to the soft options (management) or hard options (building infrastructures)? 8. Will the measure will be different in one specific region to another? For example, my report will focus on Soc Trang, but there is an expectation to translate the solution to other provinces as well. 9. In the recent years, saline intrusion in the VMD is getting worse. Is there other measures can be taken beside using dam, sluices, and gates? 10. What is your opinion about Mekong Delta Plan (2013)? Is it actually adapted in the VMD? 11. What do you think about the VMD future (barriers and opportunities) regarding land subsidence and saltwater intrusion problem? Summary: The second interviewee is Rien Dam who has experience in groundwater modeling and urban water management in Vietnam. Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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Comment [C2]: Refer to the interviews in the main text

Not only in Vietnam, but also in other places, there is a significant contribution of groundwater exploitation toward land subsidence. Even though there is no available quantification for each different factor (groundwater abstraction, natural settlement of sediment, loading, and soil oxidation), he is certain that groundwater use contributes at least 80% of the total land subsidence in the Vietnam. Even though the exact amount of extracted groundwater is unknown in the VMD, the number of pumping wells registered in the area shows that there is indeed a large amount of groundwater is used. These wells mostly belong to farmers, either an individual farmer or a collective group that used the well together. It also confirms that the sector that uses the most groundwater is indeed agriculture, and its related sectors (e.g. aquaculture). The intensive extraction of groundwater began 25-30 years ago. In general, the aquifers in the VMD are exploited. Table 2 are a good example that describes that the water is even pumped from the deep aquifer. For the surface water in the VMD, the volume of discharge in Mekong River is huge, not only in the main streams but also in the tributaries. This makes the surface water from the river should be reliable enough to be used as the main water supply. Some people show concern over the installment of hydropower dams in the upstream area. However, according to him, the amount of discharge of this river still suffices on fulfilling the demand. He mentioned that the water demand of the VMD might only constitute one per cent of the Mekong discharge. However, bigger attention is needed to maintain the water quality. It is currently polluted with the sediment and agricultural waste, which means more WWTP are required. In Soc Trang, there is one large water treatment which operated by Vitens Evides that treat the water from the Mekong River to supply the adjacent area. They store surface water in an artificial lake and treat the water over there. The new technologies such as rainwater harvesting, artificial recharge, and riverbank infiltration are possible to be implemented in the VMD. In the future, there are two options that can be developed. First, water user can be supported to be independent. This way, they are expected to practice rainwater harvesting which should be able to supply their own household water need. If the practice is successful it can also fulfill their field irrigation need, at least in small scale. The second option is to integrate this effort into a larger scale; this is in line with the project with Vitens Evides project in the Soc Trang Province. The basic principal of coping with land subsidence is to stop pumping groundwater. Limiting the usage is not enough, but stopping the abstraction is rather difficult, especially when the other water resources are not available. Another approach is focusing on managing the land use. In his opinion, this is not a very urgent measure. Also, the impact of organizing spatial planning will not give a direct impact (i.e. reducing the land subsidence rate). It depends on what type of land use, for example, changing irrigated (monoculture) shrimp farming into horticulture field. The previous land use might be water intensive (flushing the pond with groundwater) into a less water intensive one. In the end, Vietnam needs to invest in the hard infrastructures, mainly to be implemented in the coastal area. Coastal protection is important to prevent worse land subsidence and saltwater intrusion impact. The Vietnamese government has a plan to close some of the nine estuaries of The Mekong River (as known as The Nine Dragon). By closing the estuary, saline intrusion both in groundwater and surface water can be reduced. Also, a joint program in the Netherlands is now conducting research about balance islands, which may offer a solution for salinization. Basically, this idea creates a natural barrier in the estuaries that also provide a freshwater source (from the captured precipitation in the islands). Another concept to deal with saline intrusion is using subsurface water technology (refer to GO FRESH), which theoretically possible to be implemented in Vietnam. In the light of Mekong Delta Plan, he thought it is indeed being implemented somehow by the Vietnamese government. MDP itself approved and endorsed by the government, so logically, the plan is being used. However, what and how the MDP affect their policy or regulation are unknown. As additional information, World Bank is currently doing a program called Mekong Delta Integrated Climate Resilience and Sustainable Livelihoods Project for Vietnam. This project offers US$ 387 million for improving tools needed for climate smart planning and resilience. According to Rien Dam, the working plan of this project was made based on MDP, to some extent. They give different development focus for the different province as if they would implement spatial planning based on MDP scenarios. Refer to land use management as an indirect solution for land subsidence and Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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saltwater intrusion; it is important to consider the vulnerability of each area. As a solution, arranging land use in the larger scale (for example, following MDP) will give more impact because the less vulnerable area can be given less „unnecessary attention‟ while the sensitive area can be noticed more. In the future, more cooperation with aid in financial aspect offer the opportunity to the Vietnamese government for climate-proofing the country. Since land subsidence and saltwater intrusion are known to be difficult to tackle, the delta is expected to take adaptive measure and invest in the coastal protection.

Interviewee Date and time of interview Place of interview Questions:

: Edwin Sutanudjaja th : Monday, January 16 2017; 15.00-15.45 : Zonneveld Building, Universiteit Utrecht

1. Do you agree if the main reason for land subsidence and saltwater intrusion in the VMD is groundwater exploitation? 2. What are the primary factors that needed to avoid worse land subsidence rate and saltwater intrusion? 3. How about other water resources alternatives? 4. From your experience, what are the best measures for coping with land subsidence and salt water intrusion in the VMD? Will it be more to the soft options (management) or hard options (building infrastructures)? 5. What do you think about the VMD future (barriers and opportunities) regarding land subsidence and saltwater intrusion problem? Summary: dr. Edwin Sutanudjaja works in a post-doc position at Department of Physical Geography, Utrecht University. His interest includes developing a high-resolution model for various physical systems. One of his scientific papers is titled Towards a global land subsidence map in which published in the International Association of Hydrological Sciences (IAHP) Proceedings. His interview began with his disclaimer that he is not very familiar with the land subsidence from the solution point of view. He mainly works with modeling approach (which is rather technical), but during the model development, he needs to understand the principles and theories related to land subsidence and saltwater intrusion. Also, he has a great interest in Jakarta‟s land subsidence problem which to some extent is similar to the VMD problem. The land subsidence global modeling that he did with Gilles Erkens used groundwater as the main parameter. Hence, he understands that the biggest problem of land subsidence is the groundwater use. The expanding agriculture and industry practices which are not supported by adequate water use regulations made the issue worsened. Most of the cities suffer from this issue where the land subsidence main trigger is the groundwater exploitation, including Jakarta, Bangkok, and HCMC. Uncontrolled groundwater abstraction is not the only one as other processes such as natural compaction has its share in the total subsidence, but it is the one factor that could be managed. One definitive measure to limit the groundwater use is by looking for other water supply. Countries like Japan (particularly Tokyo), Venice, and the Netherlands (to some extent) had stopped to abstract groundwater. Their government had succeeded to enforce the regulation to limit the groundwater use while providing alternative water source. In Jakarta and Bangkok, rules and regulations are existing, but the enforcement is lacking. Currently, even the monitoring of (groundwater) well drilling in Jakarta is flawed. In the past, one should apply to Ministry of Energy and Mineral resource to install a groundwater well. In his opinion, Mekong Delta has an abundant source of water since the discharge of the Mekong River is more than sufficient for supplying water demand in the delta. Even during the dry season (drought), many studies showed that the delta is never experience lack of water. It even gets more water during wet season. However, similar to Jakarta‟s problem, the infrastructure in the VMD is one of the reasons for inefficient water use. The low quality of surface water in the VMD calls for proper WWTP system and laws to regulate waste water discharge. Also, the water supply system (i.e. pipeline network, etc.) requires attention to prevent leakage in the water distribution. These issues are global problems, not only in the VMD. Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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From the social aspect, Edwin said that the water management in the Vietnam could be interesting since the nation has a socialist ideology. Since long time ago, The Dutch had built many cooperation projects with Vietnam. However, the cooperation usually stopped after the feasibility report is finished. James Syvitski once gave a lecture where he criticized the practice of importing technology to the other countries with no consideration of the target country‟s social system. Hence the practice of hard measures, such as building a sea wall, needs to be reconsidered so that the society can receive and adapt well. Also, they can be involved in the maintenance. Another option of coastal protection measure includes building with nature where a pilot project in northern Java (near Semarang) coastal area (see Deltares, 2014) was being studied. However, further study is needed to ensure the effectiveness of this measure in the other are, such as the VMD. Interviewee Date and time of interview Place of interview

: John Kleinen th : Friday, January 20 2017; 14.15-15.30 th : Roeterseilandcampus C 5 floor, Universiteit van Amsterdam

Questions: 1. Based on your experience, what are the most striking features of Vietnam's population from an anthropological perspective? 2. Do these features vary from one region to another? 3. From your previous work in Red River, in what way these features can affect such water (disaster) management in the country? 4. What do you think about land subsidence and saltwater intrusion in the Vietnam Mekong Delta (VMD)? 5. From what I had researched, two main principals to cope with the land subsidence are limiting groundwater and moving to other water sources besides groundwater. What do you think about the Vietnam's population dependence of groundwater? 6. Vietnam farmers have a prolonged problem with saltwater intrusion. So far, the adaptation involves managing irrigation (gates, sluices, etc) and developing new rice varieties that more resilient toward salinity. What do you think about this? 7. From your experience, what is the prospect of public engagement level toward relatively new idea such as rain harvesting, artificial recharge, and riverbank infiltration? 8. Another measure to cope with land subsidence and saltwater intrusion includes land use management. This refers to the coastal agriculture and aquaculture practices that currently use a large amount of groundwater. The idea of building stronger sea dikes is also promising to protect the inland area. What is the impact of these ideas toward adjacent population? 9. Your works also highlight the Dutch-Vietnam relationship. Do you aware of Mekong Delta Plan (2013)? What do you think about it? 10. What about the institutional aspect in the country, especially related to the relationship between the official government, NGOs, research institutes/university, and the public? Summary: Dr. J.G.G.M. (John) Kleinen is an anthropologist and historian who has a special relationship with Vietnam history and society. His interests include the history of Vietnam, the institutional dynamics of French colonial expansion, and theory and practice of visual anthropology. According to its name, The Socialist Republic of Vietnam is a socialist country with a single ruling party which is, the Communist Party of Vietnam (CPV). The long history of Vietnam with various influences from Chinese communist, the French Colonization, and the division of the northern and southern part of the country in 1954 shaped the Vietnam we know today. After the end of the Vietnam War in 1975, the communists in the North tried in 1976 to transplant the socialist model to the South. (the terms North and South are used since 1975 used for geographical directions). They realized soon that the people of the South were not interested in the communist practice, so when household contracts in the North turned out to be a success, the south followed quickly.


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The characteristics of the Vietnamese society vary from one region to another. In Vietnam, we can discern even 7-8 different regions from the north to south of the country, sometimes expressed in regional stereotypes of the inhabitants. In general, Vietnam can be divided into delta‟s and mountainous regions: the Red River delta surrounded by uplands in the North is smaller than the vast Mekong delta in the south, while much smaller river delta‟s in central Vietnam border the central highlands (the so-called Truong Son Mountain chain). All the deltas produce wet rice, but the Mekong delta is seen as the rice basket of the country. In the Mekong-delta farmers produce 6-7 metric tons of rice pro hectare in the dry season and 4-5 tonnes per hectare in wet seasons, using fast growing IRRI-varieties which can be harvested three times a year. In the North (Red River Delta) wet rice growing faces rapid urbanization and industrialization (e.g., the biggest Samsung assembly factory). Meanwhile, Central Vietnam has the highest vulnerability of the disaster such as typhoons and the Mekong Delta is still the most important agricultural region. In colonial times, Mekong Delta is known as the rice bowl of South East Asia. Even the French colony wanted the area to be the powerhouse of rice production. During this peak time, they were able to feed the starving indigenous population of SEA. However, with the Green Revolution (with IRRI special seed) in the South and forced collectivization (after the Vietnam War), production declined. Kleinen did his main research in the northern part of the country: in 1999 he published his monograph of a Vietnamese village near Hanoi and in the same year he started a new research in coastal Nam Dinh. Later he studied fisheries in Vietnam, starting with his experiences in the north (see his publication of 2006 “Stealing from the Gods” (in A history of natural Resources in Asia (eds. Greg Bankoff and Peter Boomgaard). Working in the Ba Lat delta (estuary of the Red and the Day river) he became aware of the danger of typhoons and how people coped with natural disasters, both as part of the natural as well as a socio-economic system of the delta. Vulnerability to natural processes is a key issue in many delta regions, and his 2006 study is appropriately described as „„the characteristics of a person or group regarding their capacity to anticipate, cope with, resist and recover from the impact of a natural hazard‟‟. The rapid growths of the local population, in combination with the natural dynamics of the delta system also jeopardized coastal ecosystems and frequently result in a high competition for coastal resources. The loss of coastal wetlands by turning mangroves into an aquaculture or using the land for industrial purposes may have far-reaching consequences for the delta system. Coastal and estuarine mangroves are very efficient in trapping sediment and protecting the coast against flooding, wave activity, and erosion. Regarding the salinity problem, on one side, the farmers in most of the villages at least in Nam Dinh area were already adapted by using the IRRI-developed rice varieties, which are more resilient toward salinity. On the other side, aquaculture trends were the responsible party that damage the mangrove layer in the Nam Dinh Province (later known as one of the factors that made saline intrusion became worse). The problem with the aquaculture in general, especially in one area with developed social level, is the unequal vulnerability. When disturbance such as salinity intrusion strikes, the poor get poorer while the richer (usually the one who started the aquaculture trends) will remain stable. Historically, the Vietnam Mekong Delta (VMD) was dominated by Khmer people (originated from Cambodia), but currently, Viet people are the majority of the population there. A book called “The Khmer Lands of Vietnam” (Philip Taylor, 2014) brings a new paradigm about the indigenous people of Mekong Delta. It is that mentioned Khmer people had previously possessed and practiced their extensive local knowledge in their daily living to the extent that they understand the groundwater division in their area. Even the land use planning in the VMD area was based on Khmer‟s local wisdom. However, when the Viet came, they practice their method instead. This becomes a problem due to the difference characteristics between Red (north) and Mekong (south) River Delta which made the resources (including water) management is different. Red Delta is an area similar to the shape of a bowl while Mekong has a vast plain terrain. The Vietnamese (ethnically called Kinh) had built canals even before French colonization to bring water out from the Mekong plain, which not based on the local knowledge. The previous balanced Khmer‟s land use planning was altered by the Viet as they conquered this south area and revamped the land as if the indigenous people are savages. The social organization of the two areas is also different. Red River Delta is densely populated which resulted in their closer social interaction. Meanwhile, there is a larger distance between household settlements in the Mekong Delta which creates levels in the social organization and interaction. For Feasible Solutions for Land Subsidence and Saltwater Intrusion Issues in the Vietnam Mekong Delta

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instance, the land ownership system in the Vietnam is explained in the „household contract.' While most rice fields in the Red River Delta in the past were small sized and owned or controlled by small farmers, the agriculture field in the Mekong is managed by a great estate - large system (organization) where peasants work as labor. This system in the Mekong Delta was already well-developed. This had consequences in the 1950s and 1960s in the south. In the scope of disaster management, there are terms like vulnerability, resilience, and coping mechanism. Different level (e.g. provincial, household, individual level) will have different attitude toward the definition of those terms. Hence, it is important to determine the level of management if anyone wants to implement something. If the target perceives the risk and its vulnerability well, then the management will be easier to regulate. For example, in Japan a great bottom-up communication system is set up for advanced earthquake/tsunami early warning system which was developed from the lower level. According to Kleinen, Vietnam also has a good communication using their socialiststyle public address (PA) system. From this point of view, it is easier to address the people in the event of disaster. Moreover, the army in the socialist country reacts faster and mobilize easier during calamity. The Vietnamese population has a mindset of conquering the land from the sea. They believe that nature (esp. water/sea) is stronger and can be dangerous thus could be their enemy sometimes. This way of thinking shows that the Viet is well-aware of their vulnerability. At the same time, due to this principle, the building with the nature concept is not entirely accepted in the Vietnam, but the attitude as to adapt with nature (e.g. floating house in the Netherland) is agreeable. This idea is important to understand that any project is needed to be accepted and tailored to the public. Otherwise, it will not work for the long term. Some international joint projects were conducted in the Vietnam before, but the progress usually ceased at some point. This includes The Mekong Delta Plan. Even though they are endorsed by the government before, at the moment the report is finalized, there is no real implementation of the project. Moreover, the Viet has the tendency to shop around and compare the price to make the project delivery favorable. Even though living in such socialist country with high influence of top-down approach, the locals in the village have their will to manage everything based on their own. There is an old Viet saying that more or less means, the law of the emperor stops at the gate of the village. This is a feature for being autonomous in Vietnam lower level (i.e. the natural village) is typical of them. Although in reality, this autonomy is nowadays crushed by the communist practice, there are signals of local authority resurfaced now and then. In addition, their habit to mimic the power holder and the practice of having under the table agreement made the top-down approach not absolute. This fact gives the idea that the so-called villages (not only in the Vietnam) have more influence since they have their own autonomy, more than it‟s written in the book about communist or democratic idealism. The mimicry feature of the Viet society is one of the coping strategies as they appear to accept their fate as decided by the communist government, but underneath, there are a lot of things going. The NGO‟s role in the nation is somehow limited and unique in its own way. The local NGOs usually work in the mountainous/rural area since their movement are suppressed by the government. There are also QUANGOs (quasi-autonomous-non-government organizations) that receive fewer objections from the CPV. Meanwhile, international NGOs are more likely to be controlled by the government due to the infamous propaganda that they try to „sell peaceful coexistent‟ (between socialist and other ideology) in the past time. Nowadays, international NGOs are more into the technical matter. Mainly, the Vietnam is developing well where they become one of the middle-income nations, especially in SEA. In the recent years, some international projects (includes the one from the Dutch) aimed for the technical (hard measure) solution which more profitable from the economical point of view while the aid for creating a better institution (i.e. good governance and capacity building) became less and less. In his opinion, hard structures like sea dikes that protecting the inland area is more suitable for Saigon (Ho Chi Minh City) due to its importance. In conclusion, Mr. Kleinen is quite positive about the capability of Vietnam‟s society to cope with disaster issue (includes land subsidence and saltwater intrusion), but it is still a long way to go to really address the issue.


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Interviewee Date and time of interview Place of interview

: Philip Minderhoud th : Tuesday, January 24 2017; 09.00-09.40 : Unnik Building, Universiteit Utrecht

Questions: 1. You were involved in the VMD's subsurface modeling (2015), is it now being used by water managers in the region? 2. Does this subsurface model provide comprehensive information of aquifer condition in the VMD? From the literature review that I collected, there are four big groups of measures that can be used for coping with land subsidence and saltwater intrusion:  Reducing pressure for groundwater abstraction (regulating abstraction permit, improving surface water quality, and fixing the water distribution efficiency)  Expanding the source of water supply (artificial aquifer storage, optimizing conjunctive use of water, and rainwater harvesting)  Managing the existing land use (spatial planning)  Hard options (sea dikes and extensive water infrastructure) 3. What do you think about these measures? 4. From your experience, what are the best measures for coping with land subsidence and salt water intrusion in the VMD? 5. Do you think the VMD has the technical capability (knowledge, expertise, and technology) to implement those measures? 6. What about their institutional system? Is it supporting the process of coping with the two issues? Summary: Philip Minderhoud is one of the PhD candidates that are involved in the Rise and Fall project. His focus in the project is creating a tool based on the delta subsurface dynamics for evaluating land subsidence under different management scenarios. In 2015/2016, he developed a 3D model of VMD subsurface which modeled the land subsidence rate using the principle of hydrological response in the last 25 years. This model uses the hydrological and geotechnical data from the observation wells managed by Division of Water Resource Planning and Investigation of South Vietnam (DWRPIS) under MONRE of the Vietnam. Although currently this model has not been used by the water manager, it is expected that the improved model will be utilized to assess and predict the subsidence rate caused by groundwater abstraction in the VMD later. Hence, the model is made as open source to make the learning easier for the practitioners in the delta, in addition to a proper training to use the model. His focus in the project results in the understanding that the groundwater abstraction indeed contributes the biggest to the VMD's land subsidence. At local scale, the amount of groundwater that is pumped by the industries can be larger compared to the small farmer. However, from the delta perspective, the sum of abstracted groundwater by individual farmers in the whole delta constitutes larger quantity compared to the industries. This fact makes the groundwater management quite complicated because these farmers had invested their money in installing the pumping well to use the free groundwater. As they can use this resource without any charge, and they had done this in the last twenty years, the option to use surface water as the primary supply is arguable. The questionable quality of the surface water further justifies the groundwater use by local farmers. While the water quality (both surface and groundwater) near the main branches of the Mekong River is good, it declines in the surrounding canal network area. Regarding this issue, some WWTPs are present in the VMD to improve the quality of water. Philip referred to a paper that mentioned a collaboration project with VEI in planning to build several WWTPs alongside the river branches, but this is a very long-term project up to 2050. Currently, another project with VEI relates to the water supply network (pipeline) should be finished in the next two months.


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Knowing the condition above, other approaches are needed to provide alternatives water sources. Measures like artificial recharge and infiltration basin might not be the way for the whole delta. Especially in the VMD, the connection between the recharge area and the aquifers under the delta is unclear. In general, the pumping practice in the delta is not renewable as it is not directly restored due to the thick clay layer in the top layer. Hence, the natural recharge in the delta is rather slow and not feasible for an immediate measure. Meanwhile, rainwater harvesting could be one option to store the precipitation that falls on the land. The delta indeed has excess water in the rain season, which is usually stored in the paddy fields or discharged directly to the rivers. Independent rainwater harvesting might work to supply water for small agriculture field and household needs, but considering the scale of agriculture in the VMD is enormous, it is necessary to think of the technology to save up more precipitation. For a large scale rainwater harvesting, a storage basin is needed, but since the VMD has a very flat terrain, it provides very limited space for such storage. Philip mentioned an alternative idea about injecting this excess water to the aquifer since by reversing the pumping well owned by the households. An advanced study will be required to see what modification should be applied to the well system. The focus on the coping measure should be using groundwater as backup supply, not as the main resources (e.g. only when the surface water is saline). However, it is the other way around in the VMD. Due to the salinity intrusion event last year, the government installed many capacity wells which extracted extra groundwater as the water supply during dry/saline season. According to Philip, one of the biggest challenges for coping with land subsidence and saltwater intrusion issues in the VMD is making the public aware of the issue. In the coastal area where the salinity problem is the worst, the farmers might understand the problem of excessive groundwater extraction as they are directly affected by the impact of saline groundwater. Meanwhile, the public is indifferent about land subsidence in other areas where the groundwater quality is decent. It is easier to target the industries for groundwater tax. At the same time, the national government of Vietnam already aware of the land subsidence issue, but different cases may apply at the provincial level. Although DONREs understand the impending threats, they don‟t have yet the comprehensive plan to tackle the problem. Since they can‟t import freshwater from WWTP in other provinces, this provincial authority usually focuses on working the work on their area. For example, there is a regulation in the HCMC that limit the groundwater abstraction to maintain a certain level of the groundwater table. According to the model result, this regulation considered as a success because the subsidence rate seems to decrease after the law implementation. Another obstacle to the provincial water management is related to data availability, which if not lacking, it is scattered, unstructured, and difficult to collect. Sometimes these sets of data are secret, as they don‟t even share it with other authorities. Eventually, implementing measures in the VMD can be a challenge, but the delta does have the opportunity as they own the technical and institutional capacity to some extent.


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