Investigation And Safety Assessment Of Water Ecological Environment In Shenwo Reservoir And Surrounding Areas

China is still a developing country at this stage.The research on water ecological security started late.The research on water ecological security assessment is mainly based on qualitative analysis.The quantitative research is still in the development stage,and the quantitative research objects are mostly rivers and lakes.How to establish an assessment method suitable for reservoir water ecological security still needs to be explored.This paper investigated and analyzed the water ecological environment of the Shenwo Reservoir and the inflow river,the social and economic status of the reservoir and surrounding areas,determined the pollution status and pollution load of the pollution sources and related indicators in the study area,and determined the water ecological security status of reservoir and its surrounding areas based on the DPSIR model and the comprehensive index method.The water quality was evaluated by the single factor index evaluation method.The Shenwo Reservoir was in the V-type water body from 2013 to 2017.The TN and TP exceeded the standard in the water quality.The Qiujiawo shed section only failed to reach the V-type water standard in 2015;the Xing'an lower section only the Class IV water standard was reached in 2017;the Lanhe storage section reached Class III water standards in 2013,2016 and 2017;the algae biodiversity and benthic diversity were calculated according to the Shannon-wiener diversity index method.The evaluation showed that the water quality of the reservoir area in Shenwo Reservoir was in a state of heavy pollution from 2013 to 2017.It can be seen from the comprehensive nutritional status index method that the Shenwo Reservoir was in a medium nutrient state from 2013 to 2017.Through the accumulation of the index method,the heavy metals in the sediments of the reservoir area and the inflow rivers were evaluated.The Shenwo Reservoir was most seriously polluted by Cd,Cu and As were mildly polluted and moderately polluted;Cu and Ni in all sections of Xihe River were slightly polluted;Cu in the lower section of Xing'an of Taizihe and the front section of the Lanhe River reached moderate to moderate pollution.Through investigation and calculation,it was determined that point source pollution mainly came from urban domestic sewage discharge and industrial enterprise sewage discharge.The non-point source pollution mainly came from rural domestic sewage,agricultural fertilizer and pesticide pollution,livestock and poultry pollution.From the perspective of pollution sources,COD load and NH₃-N load mainly came from urban domestic sewage pollution;the pollution load of TN and TP in non-point source pollution mainly came from rural domestic sewage pollution and agricultural pollution.Based on the DPSIR model,the water ecological security assessment system was constructed.The weight of the evaluation system was calculated by entropy method;the water ecology of Shenwo Reservoir and surrounding areas was determined according to the comprehensive index method.Safety status:The water ecological security of the Shenwo Reservoir and its surrounding areas was in a general safe state in 2013 and 2014.It was in an unsafe state in 2015 and 2016 and was in a general safe state in 2017.Regulation management and water ecological health in the program layer,ecological response,eutrophication,capital investment,heavy metals in sediments,biodiversity functions in the factor layer,forest coverage rate,comprehensive nutritional status index,environmental protection input,alien species intrusion,storage capacity,and industrial wastewater treatment facilities in the indicator layer had a greater impact on the water ecological security of the study area.In order to improve the water ecological security status of the reservoir and surrounding areas,it is possible to optimize and improve regional water resources allocation,strictly control water pollution prevention,and carry out regional water ecological protection and restoration.