Assessment of Flood Control and Water Supply Abilities of Large Scale Reservoir using Numerical Experiment
A Case Study in the Chao Phraya River Basin, Kingdom of Thailand

Abstract

We have estimated natural runoff independent of human activities using a watershed hydrological model for the Chao Phraya River basin, Kingdom of Thailand. In order to assess the flood control and water supply capacities of two large scale reservoirs, the observed daily river discharge have been compared to the estimated values. We observed that the reservoirs' operation affected not only the increase of low flow but also the stabilization of river discharge. We estimated that the peak discharge at Hydrological Station C.2 (Nakhon Sawan city), which is the most important station for water related policies, would decrease by a maximum of 57.8% of maximum discharge and an average of 42.4 % of maximum discharge due to reservoir operations. Moreover, small and middle scale flooding was decreased by about 40 % and large scale flooding was decreased by about 35 % due to the development of the two large scale reservoirs.