Simulation Study Based On WASP And The Management Study Of TMDL For The Huangjia Lake

Since the lake basin scale is large and the geographical landscape is complex, it is difficult to conduct research for lake treatment. The total maximum daily loads control studies could provide important theoretical and practical significance for lake treatment and management. The TMDL of Huangjiahu water quality management is carried out as the study, the results of this study could provide solutions to enhance Huangjiahu water quality. It could provides a research method about management measures, strategy and direction by controlling the distribution of pollutants in Huangjiahu, in Wuhan.The main purposes of this research includes:(1) the sources of contamination in Huangjia Lake are pointed out, and the amount of major pollutants are calculated;(2) the current and historical water quality condition of Huangjia Lake and the surroundings are analyzed;(3) COD and TP are selected as the factors of total maximum daily loads, and WASP7.2 water quality model is used for simulation of Huangjia Lake water quality;(4)the total maximum daily loads of COD and TP are estimated, the best management plans are formulated.The main results are as follows:(1) According to the basic statistics collected and the data monitored from August 2013 to May 2014, it’s estimated that COD flux into the lake is 384100.04 kg/a, TN flux is 272422.38 kg/a, and TP flux is 30540.95 kg/a.(2) The concentration of COD is relatively high from August to October, After that, it gradually becomes lower and stable at between 25mg/L to 35mg/L. The concentration of TN and TP are relatively high in the winter. The water quality of Huangjia Lake is worse than Gradeⅴ.(3) WASP7.2 model is used for simulating the concentration of TN and TP value from August 2013 to May 2014. The results show that the model calibration consistency index(d) is greater than 0.85, relative error(f) is below 20%, the correlation coefficient(r) is greater than 0.8, which indicates that simulation results of COD and TP are both in the range of reasonable error.(4) after that, the Water Quality Model are used for simulating the total maximum daily loads of Huangjia Lake, The results show that the water environment capacity of COD is 154398.56 kg/a, the total reduction rate is 63.78 %. the water environment capacity of TP is 3204.70 kg/a, the total reduction rate is 90.55 %.(5)By comparison the programs to select the best distribution plan. In TP pollution load, 78 % of dispersion residents, 50 % of the lake pollution, 60 % of the rainfall sink water pollution, 97 % of colleges and universities sewage enterprises, 20 % of livestock and aquaculture are needed to cut down. In COD pollution load, 80 % of dispersion residents, 10 % of the lake pollution, 55 % of the rainfall sink water pollution, 90 % of colleges and universities sewage enterprises and 20 % of corporate livestock are needed to cut down. In order to meet TP and COD pollution load reduction requirements, the reduction programs are proposed from control engineering, management and vegetation three aspects.