Integrated management policies for water resources utilization of Dachia watershed in Taiwan

Water resources of Dachia River in central Taiwan have been used for domestic, agricultural, and hydroelectric sectors. Historically, these sectors have utilized water resources individually and integrated management of water resources is lacking. The most important reservoir for domestic water supply was destroyed in a Ritz Scale 7.3 earthquake in 1999, making efficient water resources planning and management urgent. This research is to identify acceptable management policies for the objectives of domestic and agricultural water uses as well as power generation using problem-specified VBA simulation programs, provided no new hydraulic facilities will be permitted and built in the near future. According to the most important concern of domestic water supply, three non-inferior operating policies were identified, which lead to daily domestic water supplies of 0.59, 1.07, and 1.19 million tons, respectively. The more domestic water can be obtained, the less power can be generated. Furthermore, if 25% of agricultural water demand can be released, daily domestic water supply can be increased by 270 thousand tons. Simulations have also been performed to find out the effects brought about by changing other operating parameters such as the release water volume for power generation, the operating hours of power generators, and the capacity of the domestic water treatment plant. The results of this research point out that integrated management of multiple goals of water resources in this watershed is needed, which can improve its system performance significantly.