Nonpoint source pollution management for the multipurpose dam watersheds.

Main pollution sources in multipurpose dam watersheds in Korea are highland fields, stream banks, livestock farms, roads, and construction sites. Specifically, highland fields are the major nonpoint pollution sources. Excessive organic chemicals such as fertilizer and pesticide can be exuded from the land, and the area is likely to be eroded by heavy rain. Fallow, conservative cultivation, and covering can be alternatives for soil protection and reinforcement. In addition to these, construction of detour waterways and improvement of irrigation method can minimize the impact of runoff. In the case of slope in 15% degree or more, prohibiting cultivation and restoring the surface is preferred to improving cultivation method in order to control nonpoint pollution sources efficiently.