Optimization–based Solution for Reducing Water Scarcity in the Greater Chao Phraya River Basin, Thailand: Through Re–operating the Bhumibol and Sirikit Reservoirs Using Non–linear Programming Solver

Water scarcity problem in Thailand has been intensively addressed over decades to realize its impact and to promote a systematic modernization framework and technological advancement for effective and sustainable water resources management. Accordingly, the optimization–based solution with three scenarios was conducted by aiming to reduce water scarcity in the Greater Chao Phraya River Basin through re–operating the Bhumibol (BB) and Sirikit (SK) Reservoirs using non–linear programming solver. The results reveal that water deficit can be definitely reduced by the implementation of Fmincon optimization. Water allocation between BB and SK Dams was shared in the existing 0.44:0.56 ratio for scenario 1 and current operation and 0.45:0.55 ratio for scenario 2 and 3. The proportion of water released from SK Dam in dry years and normal years is still higher than BB Dam for all scenarios and higher than the current operation particularly in normal years. However, Fmincon optimization proposes to supply water from BB Dam higher than SK Dam in wet years with the average water sharing ratio of 0.54:0.46, 0.55:0.45, and 0.55:0.45 for scenario 1, 2, and 3, respectively. This leads to the increase in water storages of two main dams for a long–term reservoir operation.