A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology, 1985

The purpose of this study is to find out the optimal operation of Huai Luang Project, Udonthani Province in Thailand for different inflows in order to meet the requirement of irrigation and Undonthani Water Supply. The Linear Programming model both deterministic and stochastic with chance constraint case are used to derive the optimal operating policy for maximizing the expected total annual benefit from irrigation for a number of reliability level which bases on probability distribution. Based on the gamma generated inflow for 100 years, the simulation model of reservoir operation is also used to find out the reliability of the system for meeting the water demand for irrigation and Udonthani Water Supply of the next 20, 40, 60, 80 and 100 years respectively. Benefit cost ratio method is used to indicate the economic efficiency of each alternative case of reservoir operation. An optimal reservoir operation for the Project has been presented. The Huai Luang Project is not a very economically viable project and has the low reliability level of only 75.0% that the water release can meet the water demand of irrigation of 80,000 and 20,000 rai in wet and dry seasons respectively with 1.75 MCM monthly water demand of Udonthani Water Supply due to the inadequate and nonuniform inflows. From the result of this study, it is expected that the irrigation areas in dry season should be limited to not more than 9,000 rai or in case of optimal benefit, the rice crop area in wet season should be reduced. The Udonthani Water Supply should consider the secondary source for using in the period of water shortage.