Thesis (D.Eng.)--Chulalongkorn University, 2013

In Thailand, climate change has been observed to show the significant impact on the hydrological processes and flow characteristics of main river basins especially in term of rainfall pattern and runoff change in recent years. In year 2011, Thailand had experienced the severe flood in the Lower Chao Phraya River Basin due to the unexpected early started rainfall in the rainy season with high intensity of storm series. The inundation caused by flood has brought the huge loss and damage of lives and economics. On the contrary in year 1993 and 2005, Thailand also experienced the extreme drought in most part of the country; it caused damage widely in agricultural area. Improving the reservoir operation to manage water effectively and cope with future flood event has become an important approach and strategy for short term flood control proposed by the government. Based on the mentioned reasons, the study on the adaptive reservoir operation to respond to future climate change using long term data was conducted. The objectives are to project the future climate, evaluate the change on hydrological variables, assess impact on the existing reservoir operation and develop the adaptive reservoir operation system under future climate condition. This study improved the reservoir release rules via fuzzy neuro inference techniques (ANFIS) with responding of water demand of irrigation, water supply, industrial and environmental release in order to minimize the water shortage and flood at the downstream. The main study area included Sirikit Dam and Nan River Basin, for the concerned area is Yom, Wang, Ping River Basin and Chao Phraya Irrigation Project. It is found that the developed adaptive reservoir operation system can mitigate the water shortage and flood more effectively, i.e. the proposed reservoir operation system can improve water release to satisfy with water demand and reduce the peak of flood at the downstream compared with the existing general and flood rule curves.