Study On The Methods Of Water Quality Assessment And Simulation And Prediction For Lake And Reservoirs

While speeding up the development on the economy, the problem of Water environment is been protruded gradually. Studing on transporting and transforming rules of the pollutant, assessing accurately water environmental quality status and predicting its development tendency are scientifically valuable and practically significant to prevent and control water environment contamination.Supported by a key project of state natural scientific fund and Inner mongolia natural scientific fund, according to the ecological water demand of ecological construction in Hunshandake sandlot, intercrossing environmental science and hydraulic science, the dissertation studied the application of fuzzy sets theory,grey systems theory,Adaptive Back-Propagation Algorithm (A-BP),Acceleration Genetic Algorithm (AGA) and their combination in water quality assessment, researched into the application of A-BP in simulation and prediction of water quality and eutrophication indexes, established the models of water quality assessment and prediction based on AGA and A-BP, It aimed at exploring a objective, exact, simple and effective method to assess and predict water environmental quality.(1) Based on a vast amount of monitoring data for the Xishanwan reservoir, fuzzy nearness water quality assessing model based on AGA and LOG curve model based on AGA and A-BP model were established, these modles and fuzzy sets theory and grey stratified strategy were employed to asseee water quality , and various methods were compared and analysed.(2) A-BP model was developed for simulating water quality distribution in time and space. According to one dimension space and time sequence, the series connected A-BP models are proposed to predict one dimension water quality space distribution and time distribution. Also, two dimension A-BP water quality was established. (3) The AGA model and A-BP model are employed to assess eutrophic grade of reservoir; the prediction modle based on A-BP of eutrophication indexes was proposed, and eutrophic grade was predicted.(4) The water environmental capacity was caculated and polluted raw of reservoir was analyzed,According to theory of water pollution control and ecology restoring,water pollution controlling countermeasures of reservoir are proposed.It was concluded that A-BP model and fuzzy nearness model based on AGA are convincible and effectual to assess water quality while comparing with other methods; Simulating precision of A -BP model for prediction water quality indexs is higher, also it can simulate simultaneously more indexes and simplify simulation process; Both AGA and A-BP models have unanimous assessing results, which indicates the models are valid; Prediction precision of A-BP model for eutrophication prediction is higher than others; Results of water environmental capacity caculated show that Xishanwan reservoir has not already environmental capacity of TP, TN and CODMn , and has still some environmental capacity of BOD5 and CODcr...