Research On Pollution Loads And Capacity Of Water Environment Of Yaohu Lake Basin

The research of this paper was based on YaoHu Lake basin. First, On the basis of ArcGISenvironment and Digital Elevation Model (DEM) data, the research adopted Automaticsegmentation, and extracted boundary of YaoHu Lake basin. and then, use of the digitalanalysis for YaoHu Lake basin with Artificial Vector Method, and obtained land use type aswell as the area, thus the research scope and object of this paper to be sure. Second, accordingto the water quality monitoring data of2010~2013and the comprehensive pollution indexmethod, the paper evaluated the current situation of water pollution, and analyzed the spatialand temporal distribution of water quality. Third, based on the monitoring work for Once aquarter with the method of in-situ test, discharge regularity and the load of point source werefigure out. Then on the premise of collecting a large amount of basic data, combined with thedistrict (county) area ratio, land use types, pollutant discharge, discharge coefficient and losscoefficient, etc, and used survey coefficient model, the research had a calculation fornon-pointload within the basin. At the same time, the research also accounted residual waterenvironment capacity of pollutants of YaoHu Lake water COD, NH3-N, TN and TP bymeasured water environmental capacity model parameters in the field. And than useExponential Growth Model and Time Series Analysis Model, respectively to predict thepopulation, economic growth and the number of livestock and poultry breeding within thebasin for2015and2020, so COD pollutants load and its remaining capacity of waterenvironment for2015and2020. With the analysis of relationship bettewm COD, NH3-N, TN,TP and their concentration in water body,forcasted their pollutants load both in2015and2020.Finally, in combination with pollution source investigation, prediction of waterenvironmental capacity and the actual social and economic situation, the paper puted forwardthe rver pollution control countermeasures and suggestions for pollution characteristics ofwatershed point source load and non-point source load. Thus, scientific basis and data supportwere provided for YaoHu Lake water pollution control, and decision-making basis wasoffered for the government protected YaoHu water resource, prevented water pollution andformulate regional.The main research results are as follows:(1) YaoHu basin across NaChang Country and QingShangHu District, and including fivetowns, more than one hundred villages, one provincial industrial park(The eastern industrialpark) and one provincial development zone(Small blue economic development zone). Thebasin area is103.64km2. There are113900people in YaoHu basin in2012, and with the ruralpopulation accounts for53.9%. For YaoHu basin, the watershed land use type is single, mainly there are paddy fields, lakes and pits, villages and towns and irrigated water, and thepaddy field accounts for58.05%, lakes and pits accounts for20.33%of the water, villages andtowns accounts for16.71%, irrigated land accounts for4.71%.(2) In2012,the YaoHu water quality had been coincidenced with Ⅲ class standardaccording to《the surface water environment quality standard》(GB3838-2002).But it changedinto Ⅱclass standard in June and July,and Ⅴ类class standard in March and April,as well asⅢ class standard in May, November and December.(3) The point source load amount of COD,NH3-N,TN and TP is2012t/a,85t/a,137t/aand14.6t/a, accounted for34.8%,33.0%,27.3%and12.3%of total pollution load, it wasmainly from QingShanHu District industrial pollution. Their typical pollution factors wereCOD and NH3-N, and they had an obvious load increases in a flowing period.(4) For nonpoint source load, the load amount of COD,NH3-N,TN and TP is3762t/a,172.8t/a,364.6.6t/a,104.2t/a, accounted for65.2%,67.0%,72.7%and87.7%of totalpollution load, and was the main pollution sources of YaoHu Lake basin. In nonpoint sourceload, there were livestock and poultry breeding pollution (38.0.0%), pollution of rural andurban life and rural and agricultural runoff pollution(54.0), these pollutants had a a largeproportion in nonpoint source load. The typical pollution factors were TN and TP.(5) According to《the surface water environment quality standard》(GB3838-2002), thewater environmental capacity of COD, NH3-N, TN and TP in YaoHu water body respectivelyare7587.0t/a,155.2t/a,161.0t/a and8.2t/a。At present, the water environmental capacity ofCOD had a portion of the remaining, but for NH3-N, TN and TP, there is no rest, and TN wasabove standard more than twice, TP was above standard up to more13times.So, Nitrogenand Phosphorus pollutants were the most important control factor that YaoHu Lake basin hadto prevent and control.(6) COD load forecasting results showed that, COD load had a big increase with therapid development of economy and the speeding of industrialization and urbanization. By2015, COD, NH3-N, TN and TP load into the lake would reach7260.7t,332.9t,675.4t and168.8t. By2020, COD, NH3-N, TN and TP load into the lake would reach10676.9t,509.9t,993.2t,248.3t.（7) To control watershed point source pollution, we should develop and implementmeasures quickely that control total capacity of water environmental, meanwhile, have moreconstruction on nonpoint source pollution load prevention and treatment of basis supportingengineering.We should find the optimal planning from the coordinated development ofpollution control social and economic.