Analysis And Forecast Of Water Quality Of Baishi Reservoir In Liaoning Province

Baishi Reservoir is located in the central of the three city Chaoyang,Jinzhou and Fuxin.n this paper,Baishi Reservoir is taken as the research object.Six conventional parameters,including permanganate index(COD_Mn),dissolved oxygen?DO?,five-day biochemical oxygen demand?BOD₅?,total phosphorus?TP?,total nitrogen?TN?and ammonia nitrogen?NH₃-N?,are selected as water quality index factors.This paper studies the water quality change of Baishi Reservoir,predicts the water quality in the future,and puts forward the corresponding countermeasures and suggestions to protect the water quality through evaluation and prediction,so as to provide feasible technical support for the improvement of the ecological environment in this area,the improvement of the living quality of local residents and the realization of the harmonious development of production and ecology.The main results are as follows:By using Pearson correlation and Spearman rank correlation,six actual observation data of water quality indexes from 2007 to 2018 were used to dynamically analyze the trend of annual changes in water quality index content and water quality index content,so as to study the correlation between indexes to clarify the change rules of water quality in recent years.According to the annual variation trend of water quality at the inlet of Baishi Reservoir from 2007 to 2018,the water quality index changes significantly in the selected period,and the environmental pollution at the inlet of Baishi reservoir has been rising in recent years.The severe non-point source pollution and soil erosion in the upstream of the reservoir lead to the increase of total nitrogen content,and the water quality cannot be improved for a long time.The water quality index presents an increasing trend,which is directly related to the different pollutants in the upstream of the water source in each year.Comprehensive Water Quality Identification index?WQI?method and fuzzy comprehensive evaluation method were used to establish a water quality evaluation model for evaluation and analysis.Finally,the data of the decade from 2008 to 2017 were selected for water quality prediction and verified according to the prediction results.Results showed that 2008-2017 the reservoir water quality can reach?class quality,meet the residents living water and agricultural irrigation water quality requirements,meet the requirements of baishi reservoir water function area,the evaluation results and published in 2019 of baishi reservoir water environmental influence evaluation results are basically identical.In addition,the2008-2017 decade,water quality of baishi reservoir in gradually improve,in meet the requirements of water function area?water,water quality development to better?class.On the basis of water quality evaluation research,the GM?1,1?prediction model of grey theory was used to establish a one-dimensional time series water quality prediction model based on the data of the decade from 2008 to 2017.The average relative error value was calculated to test the accuracy of the model,and the actual data of 2018 and 2019 were used to verify the comparison.The results show that the average accuracy of the six monitoring indexes can reach the third level after the accuracy test of the model.The model is good and has application value.It can provide a basis for the water quality prediction of Baishi reservoir and a reference basis for water environment management and planning.