Đang tải... (xem toàn văn)
THÔNG TIN LUẬN ÁN ĐƯA LÊN MẠNG Tên luận án: Nghiên cứu thiết lập mô hình thủy văn – kinh tế phân bổ nước tối ưu lưu vực sông Ba Chuyên ngành: Thủy văn học Mã số: 62 44 90 01 Họ và tên NCS: Nguyễn Thị Thu Nga Người hướng dẫn: GS. TS. Hà Văn Khối, Trường Đại học Thủy lợi, Việt Nam Cơ sở đào tạo: Trường Đại học Thủy lợi Tóm tắt những đóng góp mới của luận án: Nghiên cứu ứng dụng mô hình tối ưu trong phân tích đánh giá, phân bổ nguồn nước trong lưu vực sông và có bổ sung, điều chỉnh phù hợp cho LVS Ba. Lượng hóa được quan hệ tương quan giữa thủy văn và kinh tế cho lưu vực sông Ba trong mối ràng buộc về tự nhiên, kết cấu hạ tầng, môi trường và xã hội. Đánh giá hiệu ích kinh tế của một số chính sách dự kiến trong quy hoạch và quản lý tài nguyên nước, từ đó đề xuất các biện pháp tăng cường hiệu quả trong khai thác sử dụng nước trên lưu vực sông Ba. Hà Nội, ngày 26 tháng 12 năm 2016 Người hướng dẫn khoa học GS. TS. Hà Văn Khối Nghiên cứu sinh Nguyễn Thị Thu Nga THESIS INFORMATION ON WEBSITE Name of thesis: Research on hydroeconomic model development for optimizing water allocation in Ba river basin Speciality: Hydrology Code: 62 44 90 01 Full Name of Candidate: Nguyen Thi Thu Nga Advisor: Prof. Ha Van Khoi New contributions • Study on applying an optimizing model in analysis, assessment, and allocation of water resources in a river basin, and modifying the model for Ba river basin. • Quantifying correlation between hydrology and economic factors in Ba river basin with consideration of natural, infrastructural, environmental, and social conditions. • Evaluating economic benefits of some proposed policies in water resources planning and management, and proposing measures in order to improve water use efficiency for Ba river basin. Hanoi, December 26th ,2016 Advisor Prof. Ha Van Khoi Candidate Nguyen Thi Thu Nga
MINISTRY OF EDUCATION MINISTRY OF AGRICULTURE AND TRAINING AND RURAL DEVELOPMENT THUYLOI UNIVERSITY NGUYEN THI THU NGA RESEARCH ON HYDRO-ECONOMIC MODEL DEVELOPMENT FOR OPTIMIZING WATER ALLOCATION IN BA RIVER BASIN DISSERTATION ABSTRACT Speciality: Hydrology Code: 62 44 90 01 HANOI, 2017 This dissertation is completed at Thuyloi University Principal Advisor: Professor Ha Van Khoi Reviewer 01: Dr Nguyen Lan Chau Reviewer 02: Assoc Prof Nguyen Tien Giang Reviewer 03: Assoc Prof Ngo Le Long This dissertation will be presented to the Evaluating Committee at …………………………………………………………………………… At …… on …………… 2017 This dissertation could be found in the following libraries: - National Library Thuyloi University Library INTRODUCTION Statement of the problem Ba river basin is one of the largest inter-provincial river basins in Vietnam Based on the results of previous irrigation and hydropower planning, a series of hydraulic structures had been built In particular, there are two main irrigation structures named Ayun Ha and Dong Cam, and five large hydropower plants named An Khe, Kanak, Song Ba Ha, Song Hinh, and Krong Hnang However, when these projects went into operation, there had some impacts back to the water resource system As a result, the allocation of water resources over space and time had been changed, which thereby affects the exploitation of water in the whole basin This is one of the causes leading to the conflicts between irrigation and hydropower, upstream and downstream, economic development and environment protection Therefore, it is necessary to reconsider the issue of water allocation in Ba river basin on the basis of coordination of existing irrigation and hydropower structures to improve water use more efficiently In this context, "research on development of hydro-economic model for optimizing water allocation in Ba river basin" is chosen to study to find out a mathematical model supporting in water resources management in Ba river basin The model aims to improve water using in a more efficient way in the field of economy, social balance, and environmental protection Research Objective This research aims to address the difficult situation of water allocation problem in Ba river basin by analyzing the relationship between relative water availability and economic benefit from key-water using sectors Four following steps were taken to meet the research objective: establishing the water allocation problem for Ba river basin; developing a hydro-economic model applied for Ba river basin; applying the developed model to assess potential policies regarding to water resource management; and proposing several water resource management measures for Ba river basin Scope of study Scope of study: Research on water allocation problem of Ba river basin, time scale is a water year, time step is a month Research subjects: Water users to be considered are agriculture and hydropower The other water users including domestic, industry, fishery, and environment are considered as constant constraints Methodology The following methods applied in the research are including (i) inherited method; (ii) synthetic analysis method; (iii) statistical method; and (iv) nonlinear programming method; New contributions Study on applying an optimizing model in analysis, assessment, and allocation of water resources in a river basin, and modifying the model for Ba river basin Establishment of the quantified relationship between water availability and economic benefit from key-water using sectors Application of the model to evaluate several potential policies in water resources planning and management Based on the results, some management measures are proposed to improve water use efficiency Structure of the thesis The thesis consists of 113 pages, 30 tables, 19 figures and 72 references Besides the introduction and conclusion, the thesis consists of chapters as follows: Chapter 1: Overview of hydro-economic model applications in water resources planning and management Chapter 2: Establishment of hydro-economic problem for water allocation in Ba river basin Chapter 3: Simulation and solve hydro-economic problem of Ba river basin in GAMS Chapter 4: Impact assessment of water exploitation scenarios to socio-economic benefits in Ba river basin CHƯƠNG OVERVIEW OF HYDRO-ECONOMIC MODEL APPLICATIONS IN WATER RESOURCES PLANNING AND MANAGEMENT 1.1 Nomenclature and definitions A hydro-economic model is the combination of a hydrology model and an economic model, thereby it can represent hydrologic, technical, environmental, and economic aspects of water resource system in an integrated framework (Harou, 2009) 1.2 Introduction of hydro-economic models In a hydro-economic model, water allocation was driven and evaluated by economic value of water Water is considered as a special economic good, with the properties of both private goods and public goods The economic value of water varies by type of uses (consumptive uses or non-consumptive uses, instream uses or offstream uses, uses as intermediate good or uses as final good) Water value is also changeable over time and space The researchers can apply different methods to estimate the water value for certain situation In general, the residual method was used to estimate water value in agriculture, producer's demand function method was used to estimate water value in hydropower and industry, and consumer's demand function method was used to estimate the water value in domestic uses The hydro-economic models are different from traditional hydrological models by taking additional consideration of "varied" water values The hydro-economic models are different from economic models which usually focused on economic effects of projects Therefore, hydro-economic models were developed in order to integrate hydrologic models and economic models 1.3 Literature review of hydro-economic models Hydro-economic models have been widely applied in many researches in the field of water allocation, infrastructure, groundwater and surfacewater, institution, market and water price, transboundary conflict, water management in climate change, flood management (Harou, 2009) The study of hydroeconomic models in the world has been implemented since 1960s The study of hydro-economic models in Vietnam started later, but not widely A number of case studies were found in Ringler et al (2006), Vu Van Tuan (2007), IWARP (2007), which mostly applied for large river basins like Donna, Mekong, and Red river basins There has been no study of hydro-economic model for Be river basin, especially when the current situation of institution and natural condition has changed dramatically 1.4 Overview of integrated water resources management in Vietnam So far, integrated water resources managment (IWRM) in Vietnam has achieved some certain achievements, but there was still some limitation, especially regarding to river basin management One of the main causes of conflictions in water uses came from water resources planning Most of existing plannings are sectoral or provincial Also the procedure to issue a water resources planning is still very complex 1.5 The gaps have not been studied in water resources planning and management in Ba river basin In general, previous studies of Ba river basin were implemented basing on the assumption that water demands were fixed at certain locations Most of the studies applied traditional hydrological models to simulate the process of water allocation in the basin The results focused on finding the regions which were water shortage according to considered scenarios Some hydraulic structures or management measures would be proposed for those regions All of the studies had not considered the economic value of water which would depend on the water users, the time and the location of withdrawal In addition, some solutions were not quantitative, giving decision makers difficulty to deeply understand on the potential decisions 1.6 Summary of chapter Mathematic models were considered as very important tools supporting water resources planning and management These models could quantify the impacts of potential projects and policies, thereby supporting the policy makers Therefore, the application of a hydro-economic model is very suitable in current situation of river basin management in Vietnam, especially for Ba river basin CHƯƠNG ESTABLISHING THE OPTIMAL ALLOCATION PROBLEM FOR BA RIVER BASIN 2.1 WATER Current situation of water uses in Ba river basin Ba river basin is one of the largest national river basins in Vietnam The basin consists of roughly 13,900 square kilometers of land of Gia Lai, Dak Lak, Phu Yen, and Kon Tum provinces The topography of the basin is strongly separated by Truong Son mountains, this creates valleys from An Khe to Phu Tuc The northern, western, and southern mountains in downstream region cover the Tuy Hoa delta of 24,000 hectares which is widened toward the sea The combination of topography and south-western and north-eastern moonsoons made the basin has three different climate regions, West Truong Son, East Truong Son, and the Middle Region With these characteristics, water resources vary unevenly over time and space The annual rainfall depth in the basin is about 1,740mm The rainfall varies over space The upstream of Ba river and Hinh river have the annual rainfall depth of 3,000mm, while Cheo Reo and Phu Tuc regions have around 1,300mm The rainfall is also unevenly distributed over time The rainy season in upstream region is from May to October or November The rainy season in downstream region is later and last shorter, about to months from September to December The annual flow of Ba river basin is approximate 10 billion cubic meters The river network includes 36 1st - level, 54 2nd - level, and 14 3rd - level tributaries In general, Ba river system has a very important role in hydropower generation, irrigation, water supply, and environmental protection for Gia Lai, Dak Lak, and Phu Yen provinces 2.2 Developing process of water resources planning in Ba river basin In many years, irrigation planning, hydropower planning and other sectoral plannings had some achievements In recent years, several provinces has issued multi-sectoral planning Water resources planning of Phu Yen province was issued in 2011, and that of Gia Lai province was issued in 2015 However, the sectoral planning or multi-sectoral plannings all have disadvantages The sectoral planning was not interested in other sector uses of water Provincial water resources planning did not consider the flow connection in river basin scale This would have impact on the effect of water resources planning solutions 2.3 Reservoir system in Ba river basin Almost plannings regarding to water resources chose the solution of building hydraulic structures There are major hydropower and irrigation reservoirs, which play very important roles in water allocation They are Ayun Ha, Krong Hnang, Song Hinh, Song Ba Ha and An Khe – Ka nak reservoirs Recently, the conflicts between hydropower and agriculture, upstream and downstream, and economic development and environmental protection has appeared in Ba river basin Many researchers pointed out that the causes of these conflicts originated from the building and operation of large reservoirs The large reservoirs were built without considering fully the impacts to irrigation and environmental protection at downstream In order to get over these problems, a procedure of reservoir system regulation was issued in 2014 This newly procedure needs time to testify the effectiveness and reasonableness 2.4 Establishment of optimal water allocation problem in Ba river basin 2.4.1 Objective The allocation of water for multi-sectors in Ba river basin should have maximized economic benefit, but also ensure the requirement of balanced society and environmental protection 2.4.2 Objective function 2.4.2.1 Full objective function The most common type of objective functions in water allocation problems is to find maximize value of overall economic benefit (Brooker and Young, 1994), as in max𝑧∈(𝑧) 𝐸𝐵 = 𝑖 𝐸𝐵𝑖 𝑄𝑖 , 𝑢 (2-1) Where Q = {Qi} is the vector of water withdrawals for different sectors, including agriculture, aquaculture, domestic, industry, hydropower, environment, and recreation …; EBi is the economic value, or benefit, associated with water withdrawals Qi The units for EBi are currency per unit time (e.g $/month) There are many methods for water valuation for various economic sectors In general, economic benefits in agriculture, aquaculture, industry and hydropower can be calculated with production functions However, it is usually very difficult to determine economic benefits associated with recreational or environmental water uses The objective function in water allocation problem for Ba river basin was chosen based on previous researchs for Dong Nai river basin (Ringler, 2006), and Red River Basin (IWARP, 2008) as followed: 𝑀𝑎𝑥 𝐟 𝐱 = ( a 𝑉𝐴𝑎 + 𝑚 𝑉𝑀𝑚 + 𝑖𝑛 𝑉𝐼𝑖𝑛 + 𝑝 𝑉𝑃𝑝 ) (2-3) where VAa is water value from agriculture (including irrigation and livestock water uses); VPp is water value from hydro-power production; VIin is water value from industrial water use; VMm is water value from domestic water use 2.4.2.2 Reduced objective functions The amount of water withdrawal for agriculture in Ba river basin took about more than 90% of water consumption The largest reservoir (Song Ba Ha) in the Ba river system is located near to the downstream region With these reasons, the thesis's author proposed to reduce the original objective function to following ones: 𝑀𝑎𝑥 𝐟𝟏 𝐱 = ( a 𝑉𝐴𝑎 𝑀𝑎𝑥 𝐟𝟐 𝐱 = ( 2.4.3 + 𝑝 a 𝑉𝐴𝑎 ) 𝑉𝑃𝑝 ) (2-4) (2-5) Decision variables and state variables Decision variables are independent For full objective function, the decision variables include irrigated areas (ha) for every crop in all regions; number of cattles in seven regions; flows through turbines of hydropower plants; water demands for industry, domestic, and aquaculture For reduced objective function, the number of decision variables is reduced according to the economic components to be considered State variables are dependent variables The state variables include inflows of irrigation and livestock nodes, storages and water levels of reservoirs, inflows and outflows of river nodes, power generation yields, and ouflows of reservoirs 2.4.4 2.4.4.1 Constraints Simulation of hydro- systems The hydrologic component of the hydro-economic model included simulation of water balance of the system (Simulation of water balance of the system was included in the hydrologic component of the hydro-economic model) The operation of each node in the system had to be simulated considering the relationship with other nodes CHƯƠNG SIMULATING AND SOLVING HYDRO-ECONOMIC PROBLEM IN GAMS 3.1 Introduction of GAMS GAMS (General Algebraic Modeling System) is high-level language to solve optimizing problem GAMS includes a compiler and many solvers The general form of nonlinear programming problem in GAMS/CONOPT is as follow: or max subject to lo< x < up f(x) g(x) = b (1) (2) (3) where f(x) is the objective function; x is the variable vector; g(x) are the constraints; b is right hand side vector; lo and up are lower and upper bounds of x Objective function The user has to create a variable without domain (scalar) Then, the user will use an equation to take it as the objective function Decision variables All the variables in GAMS have to be declared by the statement Variables Example3-2Decision variable in GAMS POSITIVE VARIABLES declare the decision variable ar(n) the area of irrigated spring rice at node n Domain Description name Constraints The constraints are declared in GAMS by the statement Equations Bounds The lower and upper bounds of a variable can be described in two ways: using equations or using lower bound (lo) and upper bound (up) 11 3.2 Developing a hydro-economic model in GAMS The structure of hydro-economic model is the integration of hydrology and economic components The links between these two components are the allocated flows to different users The solution of the economic component will be the optimizing allocated water withdrawals Then, these allocated water withdrawals will decide the state of the whole system at each time step in hydrology model In contrary, water balance equations in hydrology component will change the "dynamic" constraints of economic model Basically, the hydroeconomic model is an optimize model with a simulation component The model is to find the maximize value of total net benefit from all water uses The details of the model program are shown in the Annex 3.3 Combination of scenarios for application of the hydro-economic model Some scenarios related to policy management of water resources were developed on the basis of considering the natural, economic, social and environmental conditions The results from these scenarios can assist policy makers to take measures of planning, construction or management accordingly, improve the efficiency of water utilization Base scenarios (KBCS) reallocate water resources in 2009-2010 to assess the economic efficiency of optimizing water allocation alternative compared to actual water uses The other scenarios are adjusted from the base scenarios with some changes in input data Scenarios of Group A were set up to assess the impact of natural flow changes to optimizing water allocation Scenarios of Group B refered to the effectiveness of economic policies in water management through changing economic inputs of the model Scenarios of Group C studied a number of water-saving measures in the management of water resources Scenarios of Group D reviewed the water allocation of Ba river basin in case of drought (with the flow of 1982-1983) by proposing decrease minimum capacity of hydropower plants Combination of scenarios are presented in Table 3.3 In 12 addition, all adjusted scenarios considered minimum flow requirements and food security (food crop acreage minimum) Table 3.3 Combination of scenarios Group Name CS KBCS1 KBCS2 2009-2010 A A1 A2 … A25 B C D 3.4 Water year Irrigation demand Other water demands Water demand for Hydropower generation Economic data Minimum flow requirement 3.3.1.4 3.3.1.4 3.3.1.4 3.3.1.5 No No 3.3.1.6 1978-1979 1979-1980 … 2009-2010 KBCS KBCS KBCS KBCS Yes Yes KBCS B1a B1b B1c 1980-1981 1984-1985 2003-2004 KBCS KBCS KBCS Yes Yes KBCS B2a B2b B2c 1980-1981 1984-1985 2003-2004 KBCS KBCS KBCS Yes Yes KBCS B3a B3b B3c 1980-1981 1984-1985 2003-2004 KBCS KBCS KBCS Yes Yes KBCS C1a C1b C1c 1980-1981 1984-1985 2003-2004 Irrigation efficiency: 0,8 KBCS KBCS KBCS Yes Yes KBCS C2a C2b C2c 1980-1981 1984-1985 2003-2004 KBCS Domesti c water demand increase 100% KBCS KBCS Yes Yes KBCS C3a C3b C3c 1980-1981 1984-1985 2003-2004 Changing crops KBCS KBCS KBCS Yes Yes KBCS D1 D2 D3 1982-1983 KBCS KBCS Nmin=0.55Nđb Nmin=0.45Nđb Nmin=0.35Nđb KBCS Yes Yes KBCS Crop price increase 20% Power cost increase 20% Crop yield increase to maximu m value Food security require ment Reservoirs Input data of the hydro-economic model The thesis inherited the regions of water use after IWARP, with the scheme in Figure 3.2 Each region required input data of inflows, water demands, and hydraulic structures 13 Figure 3.2 Map of water use regions in Ba river basin (after IWARP) 14 Figure3.3 Ba river basin network 15 Ba river system was described in GAMS by nodes and links There were boundary nodes, 20 flow nodes, reservoir nodes (besides quasi-irrigation reservoirs), hydropower plant nodes, 42 diversion nodes, and environmental control nodes The whole system of Ba river basin is shown in Figure 3.3 The thesis inherited inflows of boundary nodes phase 1978-2010 from IWARP Water demands in domestic, industry, aquaculture, hydropower and agriculture are also inherited from the research of IWARP The quantity and cost are referenced from existing documents and market prices with adjustment The information of hyraulic structures, hydro-power plants, and minimum flow requirements are referenced from the Operating Procedure of reservoir-system in Ba river basin Besides that, the thesis also considered requirement of food security in adjusted scenarios 3.5 Summary of chapter Contents of Chapter focuses on the introduction of GAMS system and how to set a hydro-economic model in GAMS to describe the optimization problem of water allocation of Ba River Basin The full program of the model is presented in Annex of the thesis In chapter 3, a combination of scenarios was also be set up for model application, with detailed descriptions of the input data CHƯƠNG EVALUATION OF ALTERNATIVE SCENARIOS SOCIO-ECONOMIC CONDITION OF BA RIVER BASIN 4.2 4.2.1 TO Result analysis of base scenario Evaluate the reasonableness of hydrology simulation The hydro-economic model of Ba river basin was applied to reallocate water use in the water year 2009-2010, aiming to increase the benefits from multisectoral water uses The application of the model was implemented for two base scenarios, KBCS1 and KBCS2, corresponding to two objective functions f1(x) and f2(x) 16 Figure 4.1 Simulated and observed flow at Cung Son station in 2010 Figure 4.2 Water levels of Song Hinh reservoir indifferent scenarios 4.2.2 Solution of the optimizing problem In scenario KBCS1, the solutions are the flow through turbines and the crop areas In scenario KBCS2, the decision variables are crop areas at each region 17 The values of objective functions in two senarios are compared with the estimated value of the year 2010 and shown in Figure 4.2 Figure 4.2 The net benefits from water users (Base Scenarios) 4.2.3 Selection of the reduced objective function The reservoirs in Ba river basin have been located in quite special places The An Khe – Kanak hydropower plants are located at the upstream of the main river Water is transferred from Ba river basin to Con river basin for hydropower generation Another large reservoir Song Ba Ha is located at the downstream of the main river Table 4.3 The optimal irrigated areas after KBCS Unit: Crops North & South An Khe Upper Ayun Ayun Pa Krong Pa Krong Hnang Upper Dong cam Downstream Spring rice 8800 0 4400 3740 24200 Winter rice 8800 3921.9 4400 7700 3740 24200 Spring maize 27500 2750 5054.7 8800 20388.2 4950 820 Winter maize 27500 2116.2 8800 22000 4950 820 Coffee 1100 16500 6050 24200 2200 330 Sugar cane 9900 242.7 1100 2970 11800 4680 18 Table 4.4 The actual irrigated areas in 2009-2010 Unit: North& South An Khe Crops Upper Ayun Ayun Pa Krong Pa Krong Hnang Upper Dong cam Downstream Spring rice 2364 7810 12240 2000 1729 1525 19560 Winter rice 5500 9114 16540 3000 4059 1846 2440 25000 2500 10400 8000 20000 4500 740 987 14577 5112 20957 1845 285 9000 9229 1000 2700 10725 4250 Maize (2 crops) Coffee Sugar cane Since the water value per one cubic meter in hydro-power generation is much higher than in irrigation, then water from upstream regions (such as Thuong Ayun) and middle regions (such as Ayun Pa) will be transferred to downstream regions for optimized benefit of the whole basin To avoid this situation, the objective function f2(x) would be chosen The minimum flow requirement was referenced from the Procedure of reservoir system, in which the values were transferred to one- month time step 4.3 Assessment of variant boundary flow impacts The relationship of the total net economic benefit and the total water availability is nonlinear as shown in Figure 4.3 More water is available, more benefit is generated Upto a certain threshold of water availability (about 15 billion m3), the growth rate of benefit will decline This may be due to all water demands in the basin have been satisfied, or all the reservoirs and other structures have been fully operated Variability of inflows in Ba river basin have an impact on water allocation in space Annually, the North and South An Khe region has highest ratio of water withdrawal, showed that this region has very high economic value of water use The group of hydro-power plants Ka Nak - An Khe with a total capacity of 173MW in this region transfers a large amount of water to the Con river 19 Downstream region takes advantage from upstream reservoir operation, especially Song Ba Ha reservoir Thereby, the downstream region is usually fully water supplied Besides that, the Downstream region also has the advantage of convenient location should lower production costs, and higher yields Upper Dong Cam has two large hydropower projects are Song Hinh and Song Ba Ha, featuring non-consumptive water use If the authorities want to allocate water more for the remaining areas include Upper Ayun, Ayun Pa, Krong Pa and Krong Hnang, they should adopt policies to invest in new or enhanced capacity for the reservoir in these areas Figure 4.5 Correlation between water availability and total net benefit from water usein Ba river basin Figure 4.7 Annual regional water withdrawals 20 Annually, the amount of water withdrawals for irrigation took 83.7% of total water withdrawals, for power generation (by transferring to Con river) took 9.5% The water demands for domestic uses, industry, aquaculture and livestock production accounted for only a very small proportion Rice was a kind of special water consumption crop in Ba river basin (near 50% of total water withdrawals) The economic value of rice was very low However, to ensure required food crop areas, the amount of water allocated for rice crop was still very high In order to manage water in a more efficient and economical way, rice acreage should be reduced in future This is probably true not only for the Ba river basins, but also for many other river basins in the country 4.4 Impact assessment of economic factors The economic value of water in agriculture has always been considered to be lower than in other sectors, such as industry, hydropower, and aquaculture Some economic policies such as subsidies or tax can be applied, are reflected in the changing economic inputs of the hydro-economic model For example, the inputs were considered in the thesis including agricultural product prices, power-generation costs, and crop yields Of these, the first two factors did not affected much the water allocation rates in the basin Conversely, when the crop yields increased, significantly changes of the irrigated areas in the middle area could be found in the calculation results The economic factorsbeing under consideration includecrop prices, power generation cost, and crop yields While the first two factors did not affect to the total net benefit of the basin but the last one had a significant effect The changing yields had reallocated water to irrigated areas of middle regions 4.5 Impact assessment of other factors The other input factors having been adjusted include: increasing irrigation efficiency from 70% to 80%, increasing domestic and industrial demands 21 100%, and changing crop patterns Water demands in domestic and industry are very small, mostly have no affect on water allocation in the basin Irrigation efficiency improvement had increased the irrigated areas Scenarios to consider changing the crop pattern are not effective due to lack of water areas in the middle (Ayun Pa, Krong Pa, Krong Hnang) were dehydrated for all crops 4.6 Research on reasonable allocation of water in times of drought Upon the occurrence of droughts, the adjustment of hydropower reservoirs tasks by reducing the average minimum capacity of only 0.3 to 0.5 times of guaranteed capacity can ensure other requirements for minimum food crop areas and minimum flow requirements Of course, the adjustments would affect to the total power generation of the hyro-power plants 4.7 Summation of calculation results and proposal of water resource management measures for Ba river basin Based on the initial calculated results of the hydro- economic model, many alternatives of water allocation in Ba river basin had been proposed to improve the efficiency of water uses The priority policies in water resource management of Ba river basins should be investing in regions of North & South An Khe, Upper Dong Cam, and Downstream; cutting cultivated crops from two to one in regions of Ayun Pa, Krong Pa, and Krong Hang The policy makers may consider to raise taxes for sectors having high economic value of water like industry and hydropower, or to reduce input costs for food production in agriculture by subsidies Although the later measures would have little impact on water allocation, but they would be somehow supporting social stability A technical measure to increase the irrigated water value significantly that is to increase yield of crops in the upper and middle regions 4.8 Summary of Chapter With a total of 48 scenarios, the hydro-economic models have been applied in many different natural, economic, social, and environmental conditions It 22 shows that hydro-economic models are high flexible The input and the output of the model can be adjusted up to the expectation of users The results of models allows rapid assessment of potential policies or management practices CONCLUSIONS AND FUTURE RESEARCH New contributions Study on applying an optimizing model in analysis, assessment, and allocation of water resources in a river basin, and modifying the model for Ba river basin Quantifying correlation between hydrology and economic factorsinBa river basinwith consideration of natural, infrastructural, environmental, and social conditions Evaluating economic benefits of some proposed policies in water resources planning and management, and proposing measures in order to improvewater use efficiency for Ba river basin Future research The hydro-economic model of Ba River Basin is a tool with high flexibility, is ideal for optimal water allocation problem of Ba River Basin The model has some drawbacks such as shortened the objective function, streamlining some physical relations, or economic data input This limitation is mainly due to the limited scope of the thesis For more complete model, further studies may develop additional components of economic value in the objective function, detailed input data including hydrological and economic 23 PUBLICATIONS Nguyen Thi Thu Nga, Ha Van Khoi “Reseach on water availability variation to water allocation in space and time in Ba river basin” Journal of Water Resources & Environmental Engineering – Vol 52 (3/2016) Nguyen Thi Thu Nga “Application of HEC-RESSIM model to operate reservoir system in Ba river basin” Proceedings of the annual conference on water resources - 2015 Nguyen Thi Thu Nga, Hoang Thanh Tung, Kieu Trung Hieu “Study on hydro-economic model development for Ba river basin using GAMS language” Journal of Water Resources & Environmental Engineering – Vol 49 (6/2015) Hoang Thanh Tung, Nguyen Thi Minh Tam, Nguyen Thi Thu Nga “Research of water allocation in Ba river basin” Journal of Water Resources & Environmental Engineering – Vol 48 (3/2015) Vu Thanh Tu, Nguyen Thi Thu Nga, Tran Ngoc Huan “Development and trial application of the RAM-V model for evaluation of economic efficiency from water allocation alternative in Se San river basin” Proceedings of the annual conference on water resources - 2014 ... river basin management in Vietnam, especially for Ba river basin CHƯƠNG ESTABLISHING THE OPTIMAL ALLOCATION PROBLEM FOR BA RIVER BASIN 2.1 WATER Current situation of water uses in Ba river basin Ba. .. efficiency for Ba river basin Future research The hydro-economic model of Ba River Basin is a tool with high flexibility, is ideal for optimal water allocation problem of Ba River Basin The model... in Ba river basin Chapter 3: Simulation and solve hydro-economic problem of Ba river basin in GAMS Chapter 4: Impact assessment of water exploitation scenarios to socio-economic benefits in Ba