ANALYSIS OF NONPOINT SOURCE POLLUTION IN DAHUOFANG RESERVOIR WATERSHED

Dahuofang Reservoir Watershed is located in the cold semiarid area, northeast of China. Based on the long term data analysis of the water quality, the main pollution substances of the Dahuofang reservoir are N and P, and the pollution sources of N and P are concentrated in the agricultural land use and the domestic animal feed. On the other hand, the decrease of natural forests also aggravates the loss of N and P in the earth. In order to control the state of eutrophication in Dahuofang Reservoir, much more attention should be paid for investigating the nonpoint sources pollution. At first, N, P should be systemically monitored in the whole watershed. And then, the pollution ration and the transfer mode of N and P should be studied in certain typical areas. Watershed environmental models should be developed for describing the behavior of N and P in the watershed. Finally, watershed management techniques should be studied and put in the watershed management practices.