1 AIT Asian Institute of Technology

Integrated hydro-economic equity support water allocation model: an application to Chao Phraya river basin, Thailand

AuthorDivakar, Leena
NoteA dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering in Water Engineering and Management, School of Engineering &Technology
PublisherAsian Institute of Technology
AbstractThe scarcity of water, acutely experienced when the dry season begins with limited water, no efficient criteria for water allocation and limited scope for further expansion of water supplies, can be pertinently addressed by a flexible system of allocation based on suitable decision-making criteria. The overall objective of the study is to develop a model for allocating water to the conflicting users taking the technical, equitable, economic and environmental aspects into consideration. The specific objectives are to develop a hydroeconomic equity support water allocation model to maximize the level of satisfaction and/or maximize the net economic benefit from different sectors in the basin; to estimate the net economic return from different water use sectors; to study the current allocation system and to evaluate the demand and supply situation in the Chao Phraya River basin of Thailand and; to apply the developed model to the Chao Phraya basin to improve allocation efficiency and user satisfaction level. The study develops an integrated water allocation model (IWAM), which mainly comprises a reservoir operation model (ROM), a module for estimation of net economic return (NER) to different water use sectors and a water allocation model (WAM). ROM determines the available water, which is used as an input to WAM. The water allocation model considers two single objective functions. The first single objective function (OF1) allocates water to maximize the level of satisfaction. This objective function is formulated in two ways; maximization of average level of satisfaction of all the sectors (OF1a) and maximization of minimum level of satisfaction among the sectors (OF1b). A minimum operator is used in OF1b to distribute the stress level equally among the different water use sectors. The second single objective function (OF2) allocates water to maximize the net economic benefits from different water use sectors. The model also considers a multiobjective function (OF12), which is a combination of two single objectives. A classical approach to linear programming is applied to optimize the allocation with OF1, OF2 or OF12. The SICCON (simultaneous compromise constraint) Technique and the Weighting Technique is used to optimize water allocation when OF12 is used. The optimization tool Solver in Microsoft Excel is used and the optimization program is written in visual basic with a user-friendly interface. Different techniques have been used to estimate the NER of 50, 21738, 205, 3 and 10 US$/1000m3 to water use in agriculture, domestic, industry, hydropower, and salinity control sectors. iv The study reviews the existing allocation system and analyses the current allocation practices in the Chao Phraya River basin in Thailand where acute shortages are often experienced during the dry season. The developed model is applied to the Chao Phraya River basin and the allocation results are compared with the existing system of allocation in terms of level of satisfaction and the economic benefits from different water use sectors for the dry season of 2004. The operation of Bhumibol and Sirikit reservoirs in the basin is simulated using the ROM and the applicability of IWAM is demonstrated with several scenarios by giving priority, specific % of normal demand (minimum demand to be satisfied) and giving different weights in case of multiobjective function. When OF1 is considered, the model first allocates water to a sector with the lowest normal demand and then to the sector with next higher normal demand whereas in OF2 the model first allocates water to sector with highest net economic return, followed by the next higher one. When priorities or specific % of demand are considered the model allocates water first to those sectors with priority or specified minimum demand over other sectors. OF12 with maximization of minimum level of satisfaction and net economic benefit using SICCON Technique is considered as a compromised allocation between the two objectives, with possible equal distribution of stress and higher economic benefit of about 720 million USD when compared to that of the actual release in the Chao Phraya River basin. The significance of the model results lies in the flexibility in allocating water to different sectors with maximization of level of satisfaction and net economic benefit with the limited available water. The model can be made economically efficient by estimating the marginal net benefits from different water use sectors to infer NER, instead of average net benefit used in the present study. Further, the concept of benefit sharing of the proposed water allocation model can be improved and adapted to a transboundary river basin.
Year2009
TypeDissertation
SchoolSchool of Engineering and Technology (SET)
DepartmentDepartment of Civil and Infrastucture Engineering (DCIE)
Academic Program/FoSWater Engineering and Management (WM)
Chairperson(s)Babel, Mukand S.;
Examination Committee(s)Clemente, Roberto S.;Perret, Sylvain R.;Gupta, Ashim Das;Amin, A. T. M. Nurul;Singh, V. P.;
Scholarship Donor(s)Denmark;


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