Abstract:
The Bangpra-Nongklo-Nongplalai-Dokkrai reservoir system is located at Conburi and Rayong province. The storage capacity is accordingly 117, 23, 187 and 71 million cubic meter. A unique feature of this reservoir system is that the water can be transferred between reservoirs by pipe system and the water must also be released for the downstream demand through waterway.In this study, the water allocation rule of Bangpra-Nongklo-Nongplalai-Dokkrai reservoir system was developed for 3 different situations namely : normal, critical shortage, and surplus periods. The water is allocated according to the prespecified priority of the users. The first priority is domestic water supply, the second is industries and the next are agriculture and environmental demand. Simultaneously a computer program named BNND Simulation Model was developed according to the designed water allocation rule to assist the reservoir operator to make a better decision on the water release.Simulation on reservoir water status by the BNND Simulation Model was implemented by using the data during January 1977-December 1997. The result showed that sometime Bangpra reservoir had water shortage, Nongklo reservoir often had water surplus, Nongplalai and Dokkrai reservoirs had no shortage.As indicated from the study, a lot of water was left unused in the Nongplalai reservoir therefore the East Water Company or agricultural sector should be allowed to use water in the reservoirs according to the reservoir condition. Finally the introduction of lower rule curve can decrease the magnitude of shortage so it can help the management of reservoirs during water shortage period.