The nutrient budget of Chaohu Lake

The nutrient budget was measured during 1987．5-1988．4 and calculation was made according t0 the formula：M=Q·C．Chaohu Lake has a heavy allochthonous nutrient load：23．36 g N/m2 per year and 1．43 g P/m2 per year．The Nanfei River receives wastewater from the capital city—Hdei of Anhui Province and agricultural runoff from its suburbs,and those 38．5％TN load and 37．6％TP load of the total nutrient input．The nutrient load from all point sources contributes 40．1％for TN and 36．8％ for TP of the total input．The control ofeutrophication ofChaohu Lake should reduce nutrient load from both point sources and nonpoint sources．