Study On Present Situation Analysis And Prediction Of Water Quality Based On Control Unit In The MaoZhou River Basin

In the paper, to ascertain the general situation of the Mao Zhou River Basin by a contaminating method of data collection and field survey, including natural conditions,population and economy, land use, water distribution etc. Combined with the division principle, division method, dividing the Mao Zhou River Basin into 91 calculation units preliminarily, by modifying and dressing, subdividing the Mao Zhou River Basin into 8Control Units eventually.According to the monitoring results of water quality of the Mao Zhou River Basin in2007-2014, evaluating the present situation and historical changing trend of water quality in the Mao Zhou River Basin. Water quality assessment showed that the water quality is seriously inferior V class standards of surface water, of those, chemical oxygen demand( COD), ammonia nitrogen( NH3-N), total phosphorus( TP) are the worst, thus, selecting them as the main pollution factors for the subsequent water quality prediction. By monitoring data of 2014, the Mao Zhou River Basin were worse than grade V water quality entirely, NH3-N, TP exceeding the standard wingspread, including the highest standard exceeding of NH3-N is 11.1 times, of TP is 8.2 times. The water quality trend in 2007-2014 show that before 2010 the quality became worse and worse, after 2010 the water quality was somewhat improved, but the water quality is still inferior to V class of surface water.According to the analytical methods of water pollution and statistical data of the Mao Zhou River Basin in 2013, accounting for the Basin in different types of contaminant source: knowing that Life Pollution is the largest, the COD and NH3-N discharge load accounted for 60.7% and 73.2%; followed by storm-water runoff pollution,the COD and NH3-N discharge load accounted for 27.0% and 17.4%; the industrial pollution load is relatively small, the COD and NH3-N discharge load accounting for 10.5% and 9.0%respectively; the pollution discharge load of the regular scale farms is very small, the COD and NH3-N discharge load accounted for 1.8% and 0.3% respectively.Finally, through a lot of literature about water quality prediction,combined with the hydrology and water quality Characteristics of the Mao Zhou River Basin. Selecting the one-dimensional water quality dynamic mathematical model, using implicit difference upwind scheme to discretize the equations of river water quality, according to the river flows along the counter, dividing into 4 kinds of situations, the "River-Nod-River" algorithm is adopted to solve the equations. Using the model to imitate the water quality in2014,2015, then comparing the water quality prediction results with the actual monitoring results, the assessment of the simulated concentration is relatively small, but is in still acceptable error(20%) range, the prediction method is scientific and reasonable.Therefore,this method is used to predict the river basin in 2017 and 2020 at different section of the water quality prediction, obtained in different period of rainfall(dry season, light rain,moderate rain, heavy rain) 3 important pollution factors( COD, NH3-N,TP) predicted concentrations. The results showed that water quality is significantly improved but still can’t reach the goal, then giving two methods of single pollution source control programs and a comprehensive water quality compliance program.