The accomplishment of this study is summarized as follows: 1. Following a review of the gathered study reports, data, and information, excessive nitrogen and phosphorus loads from the watershed are identified as the main cause of increasing eutrophication in Taiwan’s reservoirs. Reaeration is recommended to be the main practice to control reservoir eutrophication. In addition, the following mitigative measures are also recommended: (a) Physical processes: water column destratification, selective withdrawal, and shading (b) Chemical processes: using copper sulfate to kill algae and changing the nutrient composition in the water column (c) Biological processes: fish farming, algal growth control, and man-made wetland construction 2. Other practices for lake and reservoir eutrophication control are also identified from a number of case studies in US, Japan, Europe, and China. They include growth aquatic species such as Phragmites communis L., Trapa natans L. var. bicornis Mak., and Eichhornia crassipes Solms to control eutrophication. In addition, reaeration and destratification are used to reduce reservoir eutrophication, with wind power and solar energy as the main power source to save energy. 3. Data and information analyzed were presented at 9 regional technical workshops in northern, central, and southern Taiwan and one national workshop. Experts from academia, research institutions, regulatory agencies, and stake holders were invited to attend and to critique the results. Shinsan and Lantan Reservoirs have been identified as the first sites for implementing eutrophication control. (a) Lantan Reservoir: a man-made wetland (NT$50M as the construction cost; NT$2M as annual operating cost. Additional reaeration equipment (NT$20.66 as construction cost and NT$1M as annual operation and maintenance cost) (b) Shinsan Reservoir: 2 reaeration facility (NT$30M for construction and NT$ 5M as annual operation and maintenance cost); Sedimentation Pond (NT$50M as construction cost and NT$5M as annual maintenance cost); and automatic water quality monitoring facility (NT$3M and NT$0.5M for construction and annual operation and maintenance)

Ecological Engineering, Reservoir Water Quality, Eutrophication