To enhance the reservoir watershed soil conservation and improve its water quality, the Executive Yuan approved “Forward-looking infrastructure development program: The enhancement of reservoir watershed conservation plan”. The purpose of this project is to provide an integrated control action plan for the eutrophic Mingte reservoir. In order to achieve the goal, the tasks of this project include: (1) analyzing the data of the water quality and flow collected from Mingte reservoir watershed and Liyutan reservoir watershed, (2) establishing the stormwater sampling guidance, and green technology (e.g. Multi-Soil-Layering System (MSL), biorentation system) for pollutant reduction and developing a plan for implementing nutrient reduction, (3) applying a decision-making model for water quality management for reducing point and nonpoint source (NPS) water pollution, (4) following up the Forward-looking infrastructure development program, and (5) holding several consultation meetings. The water quality of the eutrophic Mingte reservoir was investigated and evaluated based on the monitoring data in 2019, and the water quality improvement strategies of the reservoir were presented in the project. The results showed that the major pollution load of Laotianliao River is from recreational activities in Mingte reservoir watershed. The point source pollution from the domestic sewage, civilian lodging, and leisure farms and agricultural NPS pollution seriously affected the water quality of Mingte reservoir. The research team also provided the local governments (Taoyuan City Government and Miaoli County Government) and the environmental consulting firms with guidance on developing green technology. Nutrient reduction devices (e.g. purification tank, MSL, and biorentation system) were considered and installed in watershed of Shimen reservoir, Yuanshan weir, and Mingte reservoir. The loading reduction strategies of the total phosphorus (TP) were developed for Mingte reservoir. The results indicated that the average annual TP loading into Mingte reservoir is 4,343 kg / year estimated by SWMM/ BASINS. The results showed that an integrated control action plan for both point and nonpoint sources of pollution in the watershed can be developed.

Reservoir, Nutrients, TMDL