Scientific Research and Essays Vol. 5(21), pp. 3237-3253, 4 November, 2010 Available online at http://www.academicjournals.org/SRE ISSN 1992-2248 ©2010 Academic Journals Full Length Research Paper Evaluation of irrigation and drainage systems of (Southeastern Anatolia Project) GAP, the Turkey’s largest integrated water resource development project Kasim Yenigun* and Mustafa Hakki Aydogdu Department of Civil Engineering, Faculty of Engineering, Harran University, Osmanbey Campus, (cid:1)anliurfa, Turkey. Accepted 17 May, 2010 The Southeastern Anatolia Project (GAP), the Turkey’s largest integrated water resource project, is among the world’s most important regional development projects in terms of numeric size and influence. In the present study, irrigation systems and drainage requirements within the scope of GAP in the Euphrates and Tigris Basins are investigated. With the data collected, an attempt was made to determine the potential operational problems in terms of present requirements by investigating water resources, irrigation systems, and water distribution methods, efficient use of water control structures, valves, and water, and drainage requirements and systems based on field observations. In order to solve these problems and ensure that similar problems are not experienced in future projects, recommendations related to needs are made on subjects such as management and operation models that will achieve optimum use of resources, institutional and legal contents, social and cultural behaviors, environmental interaction potential, and economic requirements. A summary of wide- ranging research carried out in the study area, problems and recommendations are presented together. Key words: GAP region, water resources, irrigation systems, drainage. INTRODUCTION Globally, the demand for water resources increases daily, managers’ efficient and effective use of irrigation but water resources are not being developed at a systems, and in terms of objective evaluation, definition, sufficient rate to meet this demand. Therefore, it has and ultimately efficient management (Hassall and become necessary to use advanced engineering Associates, 2008). technologies, and to take measures of all kinds to According to studies carried out by the World Bank in achieve water savings. Projects and construction based 80 countries, making up 40% of the world’s population, on water resources, irrigation and drainage systems are difficulties are experienced in access to water and in the long-term, high-cost, and for the most part publicly procurement of water that meets health requirements. In funded, and these need to be reflected in the water addition to the insufficiency of water resources, this resource administration, with an approach in which all situation results from the inefficiency of irrigation legal, administrative, social, technical, and economic systems, technological issues, irrigation infrastructure activities related to water, from the basin to the farm are with inadequate delivery and distribution, and inadequate integrated. operation and maintenance conditions (Southernland Irrigation and drainage planning is important in terms of Association, 2006). Despite the increased use of water in other sectors, agricultural irrigation still accounts for the greatest consumption of water on a global scale. Along with this, *Corresponding author. E-mail: [email protected], there is gradually increasing pressure for more efficient [email protected]. Tel: +90 414 318 37 80. Fax: +90 414 use of water in agriculture and irrigation. Furthermore, 318 3799. irrigation is one of the most important factors in food 3238 Sci. Res. Essays production and rural income. It is for this reason that The operation and management modeling of irrigation water management must be developed in order to systems is closely related to the high efficiency of achieve higher water efficiency and increase rural operations. Sustainable development based on irrigation, income. In water resource development and which is one of the basic aims of GAP, stands out as a management services, it is necessary that, support and compelling sector (Yenigun et al., 2008). technical assistance should be given to users in rural In order for agricultural irrigation to be successful, its areas on the level of the farm, with regard not only to yields and the expanse of the area in which irrigation is design and application, but also to the determination and planned must be taken into consideration, and it must be application of irrigation techniques. In order to make use understood that irrigation yields need to be high. of new developments and opportunities in water resource When the matter is approached within this framework, management, to manage the population increase and, there is general agreement among all relevant institutionally, water resources more efficiently, countries organizations that there is a need to determine the most must either bring about reforms, or find solutions that will appropriate operation, maintenance, and administration meet the new needs. In this regard, education and the model for water irrigation in the region. For such a model development of institutional capacity stand out as the to be successful, investigation is necessary of such most important factors (FAO, 2006). subjects as institutional and legal contents, social and Because of population increase, rapid urbanization, cultural behaviors, the potential for environmental industrialization, and irrigation systems in many regions interaction, and financial and economic needs. It is also of the world on different continents, the demand for water necessary that technical suitability be determined, as well and water resources is rapidly increasing on a daily as the ability to achieve continuity (Khatibi and Suter, basis. However, the water resources available to meet 1994). these needs are limited. As a natural consequence, The general model in the GAP region must have an capacity-increasing studies on water resources and on institutional and organizational framework that supports irrigation systems, which account for the greatest water the development of water needs and water irrigation in consumption, are being carried out based on the principle the most effective manner. Important factors include of optimum use. Irrigation rates vary depending on raising the net benefit to the maximum value, continuity, country, geographic region and production design. feasibility and flexibility. The model should have early In regions such as the Middle East, where water feasibility and the ability to become more active by resources are very limited, there are many differences in adapting to changing conditions over time. It is important the irrigation systems used by countries depending on to determine potential models for managing irrigation their economic, political, and social structures, and in the works, dividing the entire irrigation system into efficiency of their irrigation systems. For example, in fundamental operational components, and to determine projects in Syria, Iraq, and Jordan, in which open channel probable administrative units for each of them (GAP, systems are employed, the irrigation efficiency ranges 1994). from 30 to 50%, while in Israel, which predominantly uses There are many studies in the literature on water drip irrigation systems, it is approximately 90%, resource planning, and the development, and sustaina- considerably higher. bility of irrigation systems. Some of the related studies Irrigation efficiency is around 40% in African and Latin are evaluated in Table 1. American countries, and conveyance efficiency based on In the present study, water resources, irrigation irrigation systems is not high. In studies carried out in systems, and drainage requirements are investigated Latin America and the Caribbean, in contrast with studies within the scope of the Southeastern Anatolia Project focusing on the procurement of new water resources, it (GAP). The purpose of the study is to evaluate the goals has been shown that, along with the decrease in irrigation of the planning of the distribution and use of the existing investments and despite the increased demand for water, resources in terms of observational results, and to equity and efficiency are improved with water policies and present recommendations. The observations, evalua- administrative reforms in water resource systems and tions, and recommendations made in this study may form irrigations (WCA, 2006). a base of experience for similar applications. In Europe, America, and Canada, on the other hand, because pipe irrigation systems are used, this rate is higher than in countries elsewhere, at around 85%. In MATERIALS AND METHODS Asian countries, the rate is not high, at 50 to 70%, although there is some variation depending on the Study area: Southeastern Anatolia project (GAP) country’s location, the region within the country, and the The area in Turkey’s Southeastern Anatolian Region comprising the irrigation systems in use. In Australia, “The contribution to provinces of Adıyaman, Batman, Diyarbakır, Gaziantep, Kilis, the total net agricultural return of irrigated agriculture Mardin, Siirt, (cid:1)anlıurfa, and (cid:1)ırnak is designated the “GAP Region.” carried out using more than 70% of total water resources Bordered on the south by Syria and on the southeast by Iraq, and is around 50%. The achievement of feasible, sustainable comprising vast plains in the lower Euphrates and Tigris basins, the irrigated agriculture is a priority” (CLW, 2006). GAP Region contains 20% of Turkey’s 8.5 million ha of irrigable Yenigun and Aydogdu 3239 Table 1. Summary of some related literature. Literature Study area Method and conclusion of study This article evaluated the Turkish hegemony in its hydraulic control and security strategies, and the international repercussions of that strategy. It suggests that Turkey’s basin and regional hegemony is contested and constrained from different sides, not South-East least at home. It also argues that the need to access capital in the international market Warner, 2008 Anatolian, to realize these ambitions necessitated a 'passive revolution' in Turkey which opened a Turkey window of opportunity utilized by the internationalized counter(cid:1)hegemonic moves against Turkey’s dam projects in Southeast Anatolia, notably the ongoing Ilisu dam on the Tigris. This study is the chapter of “Water Resources Sustainability” and it also advocates an integrated development approach based on the sustainable development of water resources on a regional scale. This is the area where sustainable socioeconomic development and integrated water resources management intersect and yield to a holistic formulation involving multiple sectors and multiple stakeholders. The water- General based sustainable integrated regional development is covered in this chapter with its Unver, 2007 evaluation theoretical and practical aspects and through a contemporary example, the Southeastern Anatolia Project (GAP) of Turkey. This study is also deals with the prospect of using water resources for and within the broader framework of social and economic development on a regional basis and addresses the role that international organisations and the NGO community can play in overcoming for related barriers This study evaluated the effect of spatial variability of surface soil saturated hydraulic conductivity on water drainage. The random field of surface soil saturated hydraulic Quzhou conductivity was then coupled with a dynamic soil water movement model. Water Hu et al., 2007 Experiment drainage during a period of 3 months was stochastically simulated with a total water Station, China input of 354mm (including 270 mm of irrigation). This paper presents using saline water for irrigation increases water productivity by freeing up fresh water that can be allocated to domestic or other uses. The possibility of using low-cost drip irrigation with saline water to successfully irrigate a common garden Karlberg et al., Pretoria, South crop, tomatoes, was tested in this study. Even at the highest irrigation water salinity (6 2007 Africa dSm-1), a yield above the average marketable yield was achieved, indicating that low- cost drip irrigation works well in combination with saline water. Drainage water was estimated by means of a simple infiltration model (bucket model) which computes on a daily basis the inputs and outputs of soil water through rainfall and Fernández- Guadiamar evapotranspiration generated by a stochastic model of the local climate along a period Gálvez et al., valley, Spain of 50–100 years. The presence of a gravel rich horizon below 50 cm depth reveals an 2007 increase in drainage and the threat to ground water. This paper examines the environmental risks threatening sustainable urban agriculture in Kisumu municipality. The study sought to assess potential risks of contaminating Kisumu Mireri et urban agriculture produce and urban agriculture waste management. Household survey municipality, al.,2007 covered access to basic infrastructure and services, urban waste management and Kenya urban agriculture waste management. The mathematical model (SWBACROS) was applied to estimate the contribution of a shallow groundwater to the water needs of a maize crop. The model was applied with Babajimopoulos Thessaloniki the top and boundary conditions defined by the observed irrigation/rainfall events and et al., 2007 plain, Greece the observed water table depth. The authors suggest that water saving and improved water use may be achieved in surface irrigation districts when a combined farm and system approach is adopted. Goncalves et Yellow River, Utility values increase from one scenario to the next but very little for the scenarios more al., 2007 China demanding than scenario 4 that concerns improved irrigation deliveries and scheduling but not heavy changes in farm and distribution systems. Results also evidence the interrelations among improvements in the irrigation and drainage systems. 3240 Sci. Res. Essays Table 1. Contd. Water saving in irrigation is a key concern in the Yellow River basin. Excessive water diversions for irrigation waste water and produce water logging problems during the Pereira et al., Yellow River, crop season and soil salinization in low lands. Different models such as SRFR, SIRMOD 2007 China and ISAREG were used interactively to define alternatives for the irrigation systems and scheduling that would minimize percolation and produce water savings. This study refers to a region with temperate climate due to Atlantic influence and variable rainfall during the spring–summer season. Surface irrigation is traditionally Terra Cha practiced in this region, but this system is being progressively replaced by sprinkler Cancela et al., located in irrigation. To assess the irrigation requirements and to select the most appropriate 2006 northeast irrigation management practices, an irrigation scheduling simulation model was used Galicia, Spain. after calibration/validation. Schedules refer to different soil water thresholds, and fixed (40 mm) and variable net irrigation depths, which range from 30 to 54 mm. This article is about the new drainage materials were developed to replace the traditional drain pipes made from clay or concrete and drain envelopes made of organic materials or gravel. A shift from post-construction quality control to a total quality control Ritzema et al., system enables achieving a high quality of the installed systems even with the ever- Worldwide 2006 increasing speed of installation. Nowadays, basically two modes are used: implementation by a (specialized) government entity or contracted to a specialized drainage company. This report presents the surface Irrigated District V of the Bardenas Canal (Zaragoza, Spain) was evaluated, and alternatives were assessed to improve on-farm irrigation performance. The use of an average irrigation discharge of 152 Ls-1, results in a relatively low irrigation time (about 3 h ha-1). However, due to the low soil water Lecina et al., Zaragoza, retention, even this low irrigation time results in abundant deep percolation water losses. 2005 Spain The optimization of the irrigation time would lead to average application efficiencies of 76%. As a consequence, the main effect of increasing the on-farm irrigation time is to increase the irrigation interval. This article is about diagnosis of water management at the irrigation district level is required for the rational modernization of the irrigation schemes and the subsequent increase in the efficiency of water allocation and application. And study objectives were La Violada Isidoro et al., to: (i) evaluate the global irrigation performance in the 5282 ha La Violada surface- irrigation 2004 irrigated district (Ebro River Basin, northeast Spain), and (ii) estimate the water that district, Spain could potentially be conserved under two scenarios of modernization and three increased irrigation efficiencies. Second New innovative applications of PVD (Prefabricated Vertical Drain) and dual function Bangkok geosynthetics in soft Bangkok clay have been presented in this paper in addition to the Lorenzo et al., International commonly practiced versatility of PVD as artificial drainage path in the consolidation of 2004 Airport, clay soils. Thailand This paper was focused on diagnosing the quality of irrigation and to prescribe recommendations aimed at improving irrigation management and reducing the off-site pollution from a 15,500 ha irrigation district located in the Ebro River Basin (Spain). Causape et al., Ebro River Three hydrological basins were selected within the district where the main inputs 2004 Basin, Spain (irrigation, precipitation, and groundwater inflows) and outputs (actual crop’s evapotranspiration, surface drainage outflows, and groundwater outflows) of water were measured or estimated during a hydrological year. It reports on methods of linking climate change scenarios with hydrologic, agricultural, Argentina, and planning models to study water availability for agriculture under changing climate Brazil, China, conditions, to estimate changes in ecosystem services, and to evaluate adaptation Rosenzweig et Hungary and strategies for the water resources and agriculture sectors. For most of the relatively al., 2004 Romania, and water-rich areas studied, there appears to be sufficient water for agriculture given the the United climate change scenarios tested. In Southeastern Brazil, future water supply for States agriculture appears to be plentiful. Yenigun and Aydogdu 3241 Table 1. Contd. This paper focuses on irrigation, water management, and development in Chitsungo ward in the Zambezi valley. For practical purposes of policy-making, planning and implementing a people-friendly irrigation project, this paper highlights some of the Sithole, 2003 mid-Zambezi overlooked cultural and social processes of change, together with the consequences and outcomes of such interventions. This work describes the development, operational functionalities and spatial modeling applications of a Geographic Information Systems (GIS)-based irrigation management system, to be used by irrigation consortia and local governmental institutions. The Todorovic and The Apulia irrigation water management system runs on different scales of both irrigation (from Steduto, 2003 region, Italy irrigation field to irrigation consortia) and administrative (from municipality to region) units. This report presents sustainability analysis for irrigation water management in the Aral Sea region. Sustainable irrigation water management should simultaneously achieve Aral Sea two objectives: sustaining irrigated agriculture for food security and preserving the Cai et al., 2003 Region, Central associated natural environment. The current status of irrigation water management in Asia the Aral Sea region demonstrates the Aral Sea disaster as a prime example for unsustainable irrigation development. In this research study, NOAA satellite data were used to assess the performance of three large irrigation systems in Sri Lanka during the 1999 dry season (from April to July): Polonnaruwa, Kirindi Oya and Gola Oya irrigation systems. Also the paper Bandara, 2003 Sri Lanka suggests that remote sensing measurements can help objectively analyze irrigation processes throughout the country and at a monthly time step. The design and management guidelines were developed using a two-dimensional computer simulation model (COBASIM) for contour basin layouts in the study. The computer model was used to simulate and analyze the performance of single- and Khanna et al., Southeast multiple-basin layouts in response to key design variables including aspect ratio, inflow 2003 Australia rates, microtopography, vertical interval between basins and number of interconnecting drainage outlets. The paper proposes some concepts relative to water scarcity, concerning aridity, drought, desertification and water shortage, as well as policies to cope with these water Pereira et al., stressed regimes. Conceptual approaches on irrigation performances, water use and Review 2002 water savings are reviewed in a wide perspective. The suitability of irrigation methods for using treated wastewaters and saline waters is analyzed. The paper examines how a re-engineering approach can benefit irrigation management and canal operations and, hence, how the current, acute challenges to water management (e.g. competition, multiple users and protection of the environment) can be addressed. By comparing the irrigation and the industrial sectors, a re-engineering Renault, 2001 General process includes re-thinking all the processes involved in irrigation management. For canal operations, the approach should focus on an improved physical assessment of the infrastructure. This study shows the flow records of the Rivers Bure, Nar and Wensum in eastern Three low land England have been examined with the aim of identifying long-term changes in flow Hiscock et al., rivers, eastern behavior relating to variations in rainfall amount, land use, land drainage intensity and 2001 England water resources use. Mole drains in flood irrigated agriculture can rapidly fail due to high flows of irrigation Murrumbidgee water entering the mole channel through the soil cracks formed during the moling Christen and Irrigation Area, process. This research study is taking place about improvement mole drainage channel Spoor, 2001 South East stability of irrigated area. This paper also presents the trial results indicate that mole Australia channels installed with angled leg plough have the potential for much greater stability on sodic and swell/shrink soils than moles installed with current straight leg mole ploughs. 3242 Sci. Res. Essays Table 1. Contd. The response of three water delivery schedules, representing various levels of flexibility, on crop production, water saving, soil salinization, drainage volumes and water table Punjab behavior was examined. A physical-based transient soil water and solute transfer Sarwar et al., province, model, Soil–Water–Atmosphere–Plant (SWAP), was used as a tool. In the present 2001 Pakistan water deficient environment of the Indus basin, the benefits of the on-demand schedule and a fixed schedule are comparable. This paper reviews recent applications of expert systems (ES) in the domain of irrigation management. The ES development has mostly been confined to USA, Canada and Mohan and Europe, whereas in developing countries, the application of ES technique to irrigation is USA, Canada Arumugam, insignificant. The practical evaluation is a necessary step in the successful and Europe 1997 implementation of any ES in irrigation management. ESs of the expert system proper class are best suited to narrow domain problems where primarily heuristic knowledge is used to make decisions. Figure 1. Turkey and GAP region (GAP, 2006). land (Figure 1). Two of Turkey’s major waterways, the Euphrates Hydrological data from the water resources of the Euphrates and the Tigris Rivers, pass through the GAP Region. With 22 dams and Tigris Basins and 19 hydroelectric power plants, irrigated agriculture in a 1,762,000-ha area is planned in the framework of GAP, as well as After the application of various models in studies carried out to the production of 27 billion kilowatt hours of energy per year with a determine the water potentials of the Euphrates and Tigris Basins, capacity based on 7476 megawatts (GAP, 2003). hydrological data from the years 1937-1993 were collected for the Euphrates, and from 1946-1994 for the Tigris. Regarding the total water potential of the Euphrates Basin, values tend to range from slightly below 30 billion m3/year GAP water resource development projects (approximately 90% of which is within the borders of Turkey) to several billion m3/year above. As for the total water potential of the Various studies have been conducted on the Euphrates and Tigris Tigris Basin, values generally range between several billion m3/year River Basins and on water resources from other small basins within above or below 50 billion m3/year (approximately 20 billion m3/year GAP. The overall project principally consists of a package of of which is within the borders of Turkey) (Shahin, 1989; Kolars and thirteen large projects on the two large basins and their branches, Mitchell, 1991; Star and Stoll. 1987; Beaumont, 1992; Kutan, 1996; and fifteen independent projects. Bilen, 1997, 2000; Akmandor et al., 1994; Foreign Affairs, 1996; Yenigun and Aydogdu 3243 Table 2. Irrigations of Euphrates basin (DSI, 2006). Name Irrigation area (ha) Water source Irrigation method Urfa- Harran 141 835 Atatürk Dam Gravity Mardin-C.pınar 185 639 Atatürk Dam Gravity Mardin-C.pınar 149 000 Atatürk Dam Pumping Siverek-Hilvan 160 105 Atatürk Dam Pumping Bozova 69 702 Atatürk Dam Pumping Suruç-Baziki 148 500 Atatürk Dam Pumping Çamgazi 6 536 Çamgazi Dam Gravity Gömikan 7 762 Çamgazi Dam Gravity Koçali 21 605 Çamgazi Dam Gravity Büyükçay 12 322 Çamgazi Dam Gravity Atatürk Dam 29 599 Çamgazi Dam Gravity Pazarcık 71 598 Kartalkaya Dam Pumping Hanca(cid:2)ız 7 330 Hanca(cid:2)iz Dam Gravity Kayacık 13 680 Kayacik Dam Gravity Kemlin 1 969 Kemlin Dam Gravity Birecik Dam 66 021 Birecik Dam Pumping Nusaybin 7 500 Yer alti Suyu Pumping Akçakale 15 000 Yer alti Suyu Pumping Ceylanpınar 9 000 Yer alti Suyu Pumping Hacıhıdır 2 080 Hacihidir Dam Gravity Dumluca 1 860 Dumluca Dam Gravity Özi(cid:3), 1994; Özi(cid:3) et al., 2000a, 2000b). orifice consists of a double-valve system located on constant level With GAP facilities on the Euphrates and Tigris Rivers through pools. Because these structures’ foundation elevations are fixed, which more than 53 billion m3 of water per year flows within the the required flow amount depends on the difference in constant country’s borders, 29% of Turkey’s total water potential has been water head forming between the main or backup channel and the brought under control (GAP, 2006). constant head orifice pool. One sample will be taken from each basin having characteristics GAP irrigation systems representative of GAP irrigations in general, and more detailed information on them will be provided. Somewhat greater detail will In the GAP Region, more than 1.1 million ha of the planned be provided for the Urfa irrigation, from the Euphrates Basin, and irrigation is in the Euphrates Basin, while more than 0.6 million ha is the Çınar-Göksu irrigation, from the Tigris Basin. The criteria used in the Tigris Basin. Irrigations in the GAP area exhibit variation due in the selection of these two irrigations are as follows: to features such as dimensions, distribution method (pumping or gravity), hydraulic slope, and the number and condition of control i. The existence of data on both channel systems, and of sufficient structures (Tables 2 and 3). data on both irrigation networks chosen. The present irrigation total in the Euphrates Basin is 175,571 ha, ii. In terms of size, the Urfa irrigation represents large networks, and while that in the Tigris Basin is 38,353 ha (DSI, 2006). the Çınar-Göksu represents small networks. The main channel, backup channels, and discharge channels are iii. Despite the existence of many control structures in the Urfa of trapezoidal cross-section and with concrete lining. The smaller irrigation, there are none in Çınar-Göksu. backup, tertiary, and distribution channels, on the other hand, are generally prefabricated canals placed on supports above ground The irrigation systems and drainage requirements in the Euphrates level at heights that vary according to topography. and Tigris basins within the GAP were analyzed in general on the The control structures described as follows are generally used in basis of projects. Based on the data collected in these analyses diverting currents from the main channels to backup channels and and on field observations from the point of view of existing require- from backup channel to tertiary channels: ments, an attempt was made to determine potential operational issues by examining water resources, irrigation systems, and water 1. As in the Urfa-Harran irrigation system, diverting from the large distribution methods, as well as water control structures, valves, the main channels to backup channels is generally achieved by efficient use of water and drainage requirements and systems. regulators consisting of sluice gates and valves (radial and vertical). In order to eliminate these problems and ensure that similar These are controlled manually or automatically. problems are not experienced in future projects, recommendations 2. Diverting from the main or backup channels to the tertiary (small are made regarding requirements on subjects such as admini- backup) channels is accomplished by systems which consist of stration and operation that will achieve optimum use of resources, perpendicular valve combinations from constant head orifice turnout institutional and legal contents, social and cultural behaviors, structures and backup channels. Essentially, a constant head environmental interaction potential and economic needs. The 3244 Sci. Res. Essays Table 3. Irrigations of Tigris basin (DSI, 2006). Name Irrigation area (ha) Water source Irrigation method Tigris Right Side 52 033 Tigris Dam Gravity Tigris Left Side 74 047 Tigris Dam Pumping Batman Left Side 9 574 Batman Dam Gravity Batman Right Side 18 758 Batman Dam Gravity Batman Left Side 9 142 Batman Dam Pumping Tigris Right Side 200 000 Silvan Dam Gravity Tigris Left Side 57 000 Silvan Dam Pumping Garzan 60 000 Garzan Dam Gravity Nusaybin-Cizre-(cid:4)dil 89 000 Cizre Dam Pumping Silopi 32 000 Hezil Dam Gravity Devegeçidi 7 500 Devegeçidi Dam Gravity Silvan I. ve II. 8 790 Silvan Regulator Gravity Silopi-Nerdü(cid:3) 2 740 Nerdü(cid:3) Regulator Gravity Çınar-Göksu 3 582 Göksu Dam Gravity Garzan-Kozluk 3 700 Garzan Dam Gravity general evaluation framework is shown in Table 4. charged in nighttime and daytime irrigations. RESEARCH FINDINGS AND DISCUSSION The construction of reservoir areas on the main channel Problem findings obtained in this study are summarized in Table 5. Solution recommendations for these problems The construction of these reservoirs will increase the are thus presented along with their evaluation. start-up investment cost, and areas for their construction need to be designated. It is necessary to conduct additional studies and research in order to determine the Evaluations of water resources, water structures, and profitability ratio between increased irrigation production irrigations and the cost of reservoir construction. Although alternatives requiring pumpage are theoretically possible, A structural approach to water resources they are never of an acceptable value outside of situations where no other alternative is available. Over Measures aimed at preservation should be taken, such time, this alternative may become acceptable if farmers as bringing dam lake areas under absolute protection, incline towards pressure irrigation systems. education of the people living in these areas, constant inspections in connection with the administrative structure to which the areas belong, and dissuasive sanctions. The construction of regulation pools along the Building development, industrialization, and the discharge channel of wastewaters into the dam lake area must be prevented. Evaluation of the dam lake areas with regard In order to prevent fluctuations that might occur between to various usage goals and expected benefits is source control and downstream distribution systems in particularly important with regard to the system’s irrigation systems operated by the conditional demand sustainability. method, the use of regulation pools is of the utmost importance in order to prevent water loss. In irrigations in the GAP region in which distribution is carried out with Nighttime irrigations open channels, water conservation will be achieved as well as increased irrigation efficiency in fields. For The majority of farmers in areas where the irrigation example, “In periods when water demands increase to systems are located carry out nighttime irrigation. In light maximum, in a distribution system in which the nighttime of the fact that water not used by the farmers generally irrigation water demand is not of six hours duration, the runs into drainage channels and that problems may arise unstored water loss will be 20 m3 per hectare” (Halcrow- with neighboring countries, different rates should be Dolsar, 1993). Yenigun and Aydogdu 3245 Table 4. General evaluation scheme of irrigation and drainage at Euphrates and Tigris Basins within GAP. Evaluation content Proposal content Structural approach to water resources Night irrigations Construction of water storage areas on the main canal Construction of balancing reservoirs along the canal Maintenance of irrigation system Increase of irrigation efficiency Upstream control structures and spillways Evaluation for the water resources, Downstream control system hydraulic structures and irrigation Automation of control system Monitoring and measuring of flows Half-closed irrigation systems Run and contour lines Construction quality of irrigation system Appropriate usage of irrigation systems according to its technique Structures on the irrigation canal that are not in the scope of project Operation and maintenance of irrigation system Determination of drainage necessity Monitoring of ground water level Determinations for the operation Drainage design criteria and maintenance of drainage system Removal of drainage water Operation and maintenance of drainage canals Organization structure and integrated approach Collection of works done at database Determinations for the structural Organization of water union associations and institutional approach Billing of irrigation water Institutional organization structures Table 5. General characterized problems at GAP water resource systems. Evaluations for water sources, hydraulic structures and irrigations Pollution of dam reservoir areas. Information absence of local people. Discharge of wastewater to the dam reservoir area due to settlements and industrialization. Intensively daytime irrigation. Conveying of unused water to drainage channels by the farmers. Due to usage of conditional demand irrigation method, water loss and fluctuations occurs between upstream control and downstream distribution systems. Low irrigation efficiency at irrigation systems. Insufficient in field improvement services Usage of inappropriate irrigation systems. Faults depending on the farmer’s education level. The problem of using multiple ownership fields Inferior quality of upstream control structures. Lack of conveying the sufficient water on time to the downstream user’s demand during the peak irrigation period. Lack of automation at control structures. Lack of sufficient number of appropriate flow monitoring and measuring structures. Problems occurred due to surface irrigation methods (furrows and border strips) on some extent large areas. 3246 Sci. Res. Essays Table 5. Contd. Most of the irrigation project at Tigris Basin situated at the areas that has significant erosion risk. Sediments are accumulating at the slope end of the field and damaging the crops while the farmers are making slope down irrigation. Erosion of the soil in the upper elevations of the field and thus formation of rocky fields due to surface irrigation down the slope. Cracks and thus percolation of water due to poor compaction of canal portions in backfill. Inappropriate construction of joints in the lining of canal and thus occurrence settlement, cracking and sliding. Insufficient concrete protection and/or low concrete quality due to hot and/or cold climate conditions. Burning and abrasion in time due to hot and decrease at service life of the system. Technically inappropriate construction of water intake structures such as constant head orifice and outlets on the main canal. Slipping the fixed legs due to the fact that (because of) not to using plumbing “S” trap while getting water from the canals or getting water by means of breaking the canals. Excessively water leakage and waste of water due to cracked at small channels, and effect of rising ground water level and salinization happens. In case of unauthorized water intake structures on main canal, the main canal section getting smaller and flow regime changed. Stone and sand at irrigation network together with exterior sediment are affecting the flow regime. Waste materials and dead body of animals at irrigation systems are negatively effecting the flow regime and environmental health. Determinations related to operation and maintenance of the drainage system Mandatory determination of drainage requires. Monitoring of groundwater Detailing of drainage project criteria. Mandatorily removal of drainage water. Necessities related to operation and maintenance of drainage channel. Determinations for the structural and institutional approach As GAP Project has multi sectors, the lack of communication and repeated works make waste of supply and time due to insufficient and inactive coordination between the parties. Disorganization of documentation happened due to many research and work done at different time by various institutes, establishments and persons, in the scope of GAP. Social, legal, technical and institutional problems are occurs at existing water union associations and this effect the efficiencies badly. Currently, water tariffs are low and irrigation fees are taken according to crop type. Institutional organization problem This means that the daily water loss in the Harran Plain water left to flow from irrigation channels to farming irrigation alone (151,700 hectares) will be 151,700 × 20 = channels in Pakistan does not reach the farmlands 3.034 million m3. The construction of regulation pools will (Kahlown et al., 2000). not only increase irrigation efficiency, but will also have a Water losses in the upper sections of the channels vary positive impact on the drainage problem. according to the structure and condition of the main banks. In comparison with channels with lining, permeability is 2 to 10 times greater in soil banks that Maintenance of irrigation systems have been damaged (Kahlown and Kemper, 2003). Among the factors causing these types of losses are In order for the expected benefit to be achieved in damage to the channel conjunction areas, overflows over irrigation projects conducted with large investments, and the banks, dead volume forming due to excessive digging in order to avoid problems that have been encountered in in sections, and high rates of water less in the channels’ other irrigation areas, it is necessary to determine and upper sections (Trout, 1979). implement the operation, maintenance, and management Thus, given the distance between canals and the land, model for irrigation systems that is most suitable to if the water is conveyed to field channels by siphon, it regional conditions. should be possible to achieve an irrigation efficiency of Measurement results have shown that 50% of the around 80%.