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PROBLEMS ENCOUNTERED AND SOLUTION PROPOSALS ABOUT DSI ACTIVITIES IN THE EASTERN BLACK SEA REGION Bahri EGE [email protected]

Mustafa UZUN [email protected]

Mustafa Haluk FİLİZ [email protected] DSİ 22

nd

Division, 61177 Yalıncak TRABZON, Tel: 0 462 334 11 05

Ömer YÜKSEK [email protected]

Murat İhsan KÖMÜRCÜ [email protected]

Murat KANKAL [email protected] Karadeniz Technical University Civil Engineering Department, 61080 TRABZON, Tel: 0 462 377 26 41

ABSTRACT

In this study, activity areas of General Directorate of State Hydraulic Works (DSI) 22nd Division are briefly introduced and the encountered problems and their solution proposals are studied. The most important activities carried out by the 22nd Division are flood control works. Hydroelectric power, water supply, irrigation and hydrometric activities are also being performed. Various problems have been encountered during the execution of these studies, mostly because of insufficient coordination between DSI and the other related institutions. Especially, the activities of municipalities, General Directorate of Highways (GDH) and General Directorate of Rural Services (GDRS) have caused serious problems. The main problems are as follows: The housing and land filling applications of municipalities near or within stream areas; the activities by GDH, in which possibility of floods are not considered especially in tributaries; the carelessly filling of debris material obtained by road construction by GDRS into stream areas; carelessly sand and gravel dredging from streams by quarries. These kinds of problems have indicated that there are both insufficient coordination and authority disorder. The Prime Minister’s Office has published a circular entitled “Stream Areas and Floods” in order to solve these problems.

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INTERNATIONAL CONGRESS ON RIVER BASIN MANAGEMENT

In this paper, detailed knowledge about the above problems is presented and the role of the aforementioned circular in solving the problems is emphasized. Keywords: Eastern Black Sea Region, DSI Activities, Streams, Prime Minister’s Office’s Circular INTRODUCTION Human beings have a great capacity to adapt to varying climatic conditions and environments, but remain vulnerable to adverse impacts of weather and climate. In addition to the direct impacts of loss of life and property damage, there are indirect impacts such as increased exposure of survivors to other damages such as contaminated water supplies and landslides, and the disruption of traffic and trade. The indirect impacts are quite numerous and often difficult to quantity. Floods are among the most common natural disasters and in terms of economic damage, the most costly. Flooding is a natural phenomenon which occurs inevitably from time to time in a river or drainage basin and cannot be prevented, but of which effects can be mitigated. The problems associated with disastrous flooding arise because of man’s deliberate occupancy of flood-prone areas, undertaken for a variety of good reasons. These include the suitability of flood plains and riverbanks for agriculture and other forms of primary production, for convenience for transport and navigation, for appropriate topography for towns and cities, and for proximity to domestic, industrial and irrigation water supply.

Devastating flood events have occurred in various river basins of Turkey, especially in recent years. In many cases, floods have caused deaths, suffering and extensive damages to both public and private properties. A flood inventory of 776 cases was prepared for easy access to 68 different parameters encompassing the geographical, topographical, hydrological, meteorological, and synoptic characteristics of each flood. By categorization of the available data in hand, spatial and time distributions of past flood events were determined. Accordingly, on the average 18 flood events occur in a year and they take about 23 lives. Almost after each flood, the government has paid a large proportion of the damage, in addition to losing significant revenues due to the consequences of economic disruption [Gürer and Özgüler, 2004]. According to flood reports prepared by General Directorate of State Hydraulic Works (DSI), annual average flood damages are calculated nearly 86 million US$ damage per year [DSI, 1970-2005]. Floods are due to heavy rainfall on the coastal areas of the western and southern parts of Turkey or to a sudden snowmelt in the eastern, mountainous part of southeastern Turkey. In the northern and central parts of the country, including the Eastern Black Sea Basin, both factors may occur depending on the time of the year [Yüksek, et al., 2006 b]

Land-use, particularly wrong and even illegal land-use, is a most important factor in Turkey when dealing with natural damages, especially the flood damage. The consequences of flooding are strongly influenced by the commercial development

PRACTICES ON RIVER BASIN MANAGEMENT

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and urbanization of many areas. In order to absorb the increasing population, new settlements have been built, mostly illegally. The capacity of the storm sewers and flood detention structures in the cities is often inadequate to control large floods. The conveyance capacity of the creeks is greatly reduced during floods by building the walls of houses in the stream beds. Such non-meteorological factors aggravate effects of the floods. Very big and destructive floods have occurred in The Eastern Black Sea Region (EBSR) of Turkey, which comprises of 5 provinces; Giresun, Trabzon, Rize, Gümüşhane and Bayburt. In this region, 54 big floods have taken place between 1955-2005 years, causing 258 death and nearly 500 000 000 US Dollars of damage. Most of the floods have occurred in July, June and August. In these months, the superposition of intensive rainfall with snowmelt of upland areas has caused big floods [Yüksek, et al., 2006, b]. In this study, activity areas of General Directorate of State Hydraulic Works (DSI) 22nd Division are briefly introduced and the encountered problems and their possible solution proposals are focused. The most important activities are related to flood control works. Hydroelectric power, water supply, irrigation and hydrometric activities are the other important studies. Various problems have been encountered during the execution of these studies, mostly because of insufficient coordination between DSI and the other related institutions and due to authority disorder. Especially, the activities of municipalities, General Directorate of Highways (GDH) and General Directorate of Rural Services (GDRS) have caused serious problems. The main problems are as follows: The housing and land filling applications of municipalities near or within stream areas; the activities by GDH by not taking into account possibility of floods in tributaries; the carelessly filling of debris material excavated during road construction by GDRS into streams and carelessly sand and gravel dredging from streams by quarries. These kinds of problems have brought into light both insufficient coordination and authority disorder. The Prime Minister’s Office has published a circular entitled “Stream Areas and Floods” in order to solve these problems. In this paper, detailed knowledge about the above problems is presented and the role of the aforementioned circular in solving the problems is emphasized. THE EASTERN BLACK SEA REGION AND ACTIVITIES OF DSI 22ND DIVISION

Eastern Black Sea Region (EBSR) is located between on the north eastern coast of Turkey, between 40015’ to 41034’ north latitudes and 36043’ to 41035’ east longitudes. The basin is surrounded by Eastern Black Sea Mountains on the south and Black Sea on the north (Figure 1). Total area of the region is 33 203 km2. Nearly 2 500 000 people are living in the region. The region is split by valleys reached from the sea into south

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zones. The strata of the region are generally made of impermeable or semi permeable volcanic rocks, which prevent the rainfall from percolation and force the water to flow as runoff [Üçüncü et al, 1994]. The Black Sea Coast receives the greatest amount of rainfall. The eastern part of that coast averages 1,400 millimeters of rainfall annually and is the only region of Turkey that receives rainfall throughout the year. The wettest region is the EBSR where annual rainfall can reach 2,200 millimeters. Most of the drainage areas of the rivers in the basin are featured by short main courses, their steep slopes and rather dissected with deep valleys and the tributaries have river bed slope bigger than 10 to 20 % at upper reaches. Floods are due to heavy rainfall or to a sudden increase in air temperature, resulting in snow melt in the mountainous parts. During the flood, due to high sediment, the river flow is muddy and viscous has high velocity. The forest cover has been damaged by man and the water retaining capacity of drainage basin was decreased, therefore erosive energy is very high. The large amount of erosion and debris materials dragged by the flowing water and deposited in the flatter low lying areas [Gürer and Özgüler, 2004]. The Eastern Black Sea Region (EBSR) has great advantages from the view point of Small Hydropower (SHP) potential. Because, the annual average precipitation is the highest in the country and the region covers sharp valleys and there are a lot of steep streams with considerable discharges and heads [Yüksek, et al., 2006 a].

Figure 1 Location map of EBSR

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According to tables presented by Electrical Power Resources Survey and Development Administration (EIE), there are 166 projects in Turkey, being studied with capacity of 9 742 MW and annual energy potential of 33 793 GWh. 73 projects with 8 644 MW and 29 375 GWh/year, are planned with various kinds of dams and remaining 93 projects with 1 098 MW and 4 418 GWh/year are planned as “run of river”, without storage and dams. Within the run of water projects, 47 projects (50.5 %) with 149.71 MW (13.6 %) capacity and 768.41 GWh/year (17.3 %) will be made in EBSR. Various local SHP projects may be easily and economically developed. Many of the SHP projects in EBSR are under investigation and the preliminary reports of some of them are either under preparation or ready [Yüksek, et al., 2006 a]. In addition to flood control and hydroelectric power studies, water supply, irrigation and hydrometric activities are also being performed by DSI 22nd Division. ENCOUNTERED PROBLEMS AND ROLE OF THE CIRCULAR IN SOLVING THEM

Psychological factors have become one of the prevailing human factors that cause great flood damages hree great and widespread floods, which took place in 1929, 1959 and 1990 (nearly within 30 yearly time intervals) in EBSR, seemed to be forgotten by people and state; so, a possibility of another devastating flood may took place could not be remembered. As a result of this indifference, private and official institutions have inexcusably interfered to the natural situation of stream zones, causing narrowing of stream sections and forcing the streams to flow within “artificially narrowed” conduits [Üçüncü et al, 1994]. In this chapter, the problems encountered by DSI 22nd Division during the execution of its activities and especially flood control studies are introduced and the role of the Prime Minister’s Office’s Circular entitled “Stream Areas and Floods” in solving these problems are studied. The problems and possible measures by the circular are classified as related to; settlement, transportation, hydraulic structures and sediment. In the following sections, “problems” means the encountered problems and “measures” means the countermeasures to be taken against these problems, which have been cited in the circular, including the item number of the circular.

SETTLEMENT

Problems: Despite the fact that the economical life of the residents of the region depends primarily on agriculture, the areas suitable for agriculture are rather scarce and expensive. Therefore, the residents have been forced to get some areas on the alluvial soils within the river beds and riverbanks. For the similar reasons, the people have established great settlement and industrial facilities near or within the stream zones.

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The consequences of flooding are strongly influenced by the commercial development and urbanization of many areas in recent years. In order to absorb the increasing population, new settlements have been built, mostly illegally. The increasing property value has made the flood risk worth taking and has encouraged people to settle in the flood-prone zones despite their known danger. In some instances, the urbanization of certain areas progresses visibly from one month to the next. Parallel to this “explosion” of housing areas, there has been a substantial increase in the construction of asphalt roads, parking lots and pavements in the cities. Insufficient flood control structures and the lack of channel improvements in the creeks have further enhanced the flood damage. The capacity of the storm sewers and flood detention structures in the cities is often inadequate to control large floods. The conveyance capacity of the creeks is greatly reduced during floods by building the walls of houses in the stream beds, constructing roads on the stream beds and throwing garbage and construction material into the creeks. These non-meteorological factors aggravate the consequences of the floods to a great extent [Yuksek, et al., 2006 b]. During the conducting cadastral surveys in stream valleys, title deeding works without considering DSI’s opinion have caused problems during improvement works. Uncontrolled settlements in the places where field stability is not good and topographic conditions and field situation are not suitable (especially out of official settlement areas) have resulted in serious problems. Variations both in field usage (eg, variation of forest areas into tea fields) and housing manner (7 to 8 flatted houses, instead of traditional 1 to 2 flatted houses) are the other problem. Construction of houses and hydraulic structures in a manner that block natural stream flow has resulted in increment in flood effects.

Measures: “During the make of improvement plans of province, administrative district and town, the recommendations and measures of DSI must be strictly obeyed”(Item 1). “The upper sides of streams can not be closed, unless taking permission from DSI in the cases of compulsory conditions. Moreover, all kinds of structures within stream zones must be constructed only by an approved project” (Item 2). TRANSPORTATION

Problems: Because of topographic features of the region, the road alignments have to be planned passing through beds of valleys. The slopes of these roads should be pro-


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tected by hydraulic structures, especially, when crossing the roads with stream beds, it is very important to provide enough improvement width. Sometimes, although cross sections are supposed as sufficient in design, because of the alteration in flow conditions, some negativity can be arisen. Another problem related to transportation is the necessity of more roads as a result of scattered settlement areas. That no enough structures can be constructed for protecting the road slopes has resulted in landslide towards streams and decreased their flow capacity.

Measures: “In the design of road and hydraulic structures in the zones where are in the responsibility of General Directorate of Highways (GDH), the opinion of related GDH Division has to be taken into consideration and these structures must be constructed according to technical standards of GDH” (Item 7). “During the road construction, in order to provide water flow in low areas and to make it possible to construct substructures, related institutions have to make enough culverts by taking into account DSI’s opinions” (Item 8). HYDRAULIC STRUCTURES

Problems: Lacks of sufficient qualification of hydrological calculations, which are essential in designing of hydraulic structures, have been a serious problem. Another problem is the fact that, the slopes of levees are filled by soil in order to use for agricultural purposes, which in turn has resulted in narrowing of stream sections. Destroying of the existent flood control structures without permission for accessing roads to enter rivers may also cause increase in flood damages.

Measures: “It is compulsory to consider the opinions of related DSI division and to construct the structures according to these opinions before constructing various hydraulic structures on streams, such as bridges and culverts; and various kinds of structures, including roads, energy conveying, oil, gas, telephone and fresh and waste water lines; which are to be constructed near or on streams” (Item 3). “The structures that cause to narrow and block flow sections can not be constructed; to be constructed either by official or private institutions. If it is determined by controls that such structures have already been constructed, they must be urgently destroyed” (Item 4).

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SEDIMENT

Problems: The main problems related to sediment are as follows: Uncontrolled sediment dredging from stream beds, which have resulted in unwanted alterations at flow conditions; inappropriate site selection of sediment quarries; breaking natural flow conditions and scouring of structure toes as a result of excessive sediment dredging; and decreasing flow sections of flood control structures by transported sediment.

Measures: “Location of sediment dredging must be preferably at up drift sides and at least 750 m distances from bridges. Dredging of sediment can not alter the natural flow conditions. If dredging has to be carried out at down drift side, the distance from bridges should be determined according to topographical, hydraulic and sediment conditions and this distance can never be less than 1000 m. The permissions of quarries which do not obey these rules must be cancelled” (Item 5). “The activities of sand, gravel and stabilized material quarries, which have to be built within or near to streams, should be carried out according to DSI’s opinions. The permissions of quarries which do not obey these opinions must be cancelled” (Item 9). “Excavated material, debris and various kinds of wasted material are being poured to roads, basins and stream beds and as a result, the conveyance capacities of the streams have seriously been decreased and flood risk has been increased. The pouring of any kind of material to streams must be strictly prevented by official authorities” (Item 10). SUMMARY AND CONCLUSIONS

Very big and destructive floods have occurred in The Eastern Black Sea Region (EBSR) of Turkey. In this study, activity areas of General Directorate of State Hydraulic Works (DSI) 22nd Division are briefly introduced and the encountered problems and their possible solution proposals are focused. The most important activities are related to flood control works. Various problems have been encountered during the execution of these studies, mostly because of insufficient coordination between DSI and the other related institutions and due to authority disorder. The Prime Minister’s Office has published a circular in order to solve these problems. In this paper, general knowledge about the above problems is presented and the role of the aforementioned circular in solving the problems is emphasized. The problems and some proposals to solve them are studied in the light of the aforementioned circular.

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It is hoped that, by applying this circular most of the flood problems, which have been arisen by insufficient coordination and authority disorder, may decrease. However, it is obvious that, the problems are too serious and great to be solved simply and solely by a circular. Non-structural flood protection measures such as early flood warning system and the modification of land use in the region should be initiated as soon as possible in the case study area. The other non-structural measures comprise watershed management and improvement, flood insurance, organization of flood management studies, education of the people and the informing of the stakeholders. Stopping the deforestation and improving the rain and discharge gauging mesh, which in turn permits more accurate flood prediction, also should be significantly considered as non-structural measures. REFERENCES

Gürer, İ., Özgüler, H. (2004), Integrated flood management case study Turkey: Recent flood disasters in Northwestern Black Sea Region, WMO/GWP Associated Programme on Flood Management. DSI (General Directorate of State Hydraulic Works) (1970-2005), Annual flood reports, Ankara, Turkey (in Turkish). Üçüncü, O., Önsoy, H., Yüksek, Ö. (1994), “A Study on the environmental effects of 20 June 1990 flood in Trabzon and its neighborhood”, Turkey, 2nd International Conference on River Flood Hydraulics, 22-25 March 1994, York, England, 501-512. Yüksek, Ö., Kankal, M., Üçüncü, O. (2006 b), “Analysis of big floods in the Eastern Black Sea Basin of Turkey”, Natural Hazards (Accepted for Publication). Yüksek, Ö., Kömürcü, M.İ., Yüksel, İ., Kaygusuz, K. (2006 a), “The role of hydropower in meeting Turkey’s electric energy demand”, Energy Policy, 30, 3093-3103.