Monitoring And Analyzing Of Panjiakou-Daheiting Reservoir Water Quality Change Based On Multi-Source Remote Sensing Images

The water quality of reservoirs is closely related to people’s lives in water source area,is directly related to people’s water security problems,should be paid close attention to management and key monitoring,to be able to timely discover and solve the problem of water quality deterioration.Panjiakou reservoir and Daheiting reservoir are important water source reservoirs in the BeiJing-TianJin-HeBei region in north China,and the headwaters of the Water Diversion Project from Luanhe River to Tianjin City,because of poor management,lead to overload of the fish and water quality deterioration.The net cage was cleaned in November 2016 and cleared in May 2017.This paper mainly analyzes the water quality parameters(turbidity,total suspended solids concentration,chlorophyll a concentration,DO,COD,TP)after cleaning the cages of Panjiakou Reservoir and Daheiting Reservoir.The changes of water quality parameters to discover the characteristics of water quality changes and provide reference for water quality monitoring and analysis for the improvement and management of water quality in Panjiakou Reservoir and Daheiting Reservoir.This paper establishes a water quality parameter inversion model for Panjiakou Reservoir and Daheiting Reservoir,and obtains a spatial distribution map of water quality parameters for different remote sensing satellites based on Sentinel-2 MSI,GF-1 WFV and Landsat-8 OLI remote sensing satellite data.The obtained water quality inversion result data is weighted according to collective thinking,and the inversion results of the multi-source satellite water quality parameters are combined,so that the multi-source satellite data can simultaneously monitor the Panjiakou Reservoir and the Daheiting Reservoir by remote sensing.It can improve the temporal resolution of water quality monitoring by remote sensing.Based on the basis of this study,the water quality parameters of the long-term sequence of the Panjiakou Reservoir and the Daheiting Reservoir were retrieved based on the GF-1 WFV data,include the turbidity,total suspended solids,chlorophyll a concentration,DO,COD of Panjiakou Reservoir and Daheiting Reservoir and the TP of Daheiting Reservoir from April 2017 to October 2018.And further analysis of changes in water quality characteristics Panjiakou Reservoir and Daheiting after the cages clean and the possible causes of the change analysis,improve traceability and the ability to find the causes of the risk of contamination of ground monitoring data binding.Through research,the water quality of the Panjiakou Reservoir is better than that of the Daheiting Reservoir.The total phosphorus content of the reservoir after the cage cleaning is significantly reduced,and the water quality has improved.The current total of the Panjiakou Reservoir and the Daheiting Reservoir Phosphorus levels are still high and are one of the key factors for improving water quality.Through the spatial distribution of water quality remote sensing data,it can be found that in the upstream area of the Panjiakou Reservoir and in front of the dam,the upstream of the Daheiting Reservoir,the water quality deviation,especially in the upper part of the Daheiting Reservoir,the higher the concentration of leaf a.The eutrophication of water bodies is serious.In 2017,water blooms appeared in some areas.Cleaning the cage can improve the condition of some water components.However,due to the large reduction of fish in the short term,the balance of the water ecosystem is destroyed.Under the high temperature conditions in summer,the composition of the reservoir sediment may be released into the water layer.On the surface,the concentration of chlorophyll a and total nitrogen in the water body becomes high,and the eutrophication of the water body is serious.This paper’s contributions are:(1)Multi-source satellite remote sensing image data with different spatial resolution and temporal resolution are used to invert water quality parameters and merge them.The possibility of multi-source remote sensing image fusion inversion is obtained through research,and the time resolution and inversion accuracy of water quality remote sensing monitoring are improved;(2)Using GF-1 WFV data to retrieve the time series water quality parameters of Panjiakou Reservoir and Daheiting Reservoir,The spatial distribution of turbidity,transparency,total suspended solids concentration,chlorophyll a concentration,dissolved oxygen in Panda Reservoir and total phosphorus in Daheiting Reservoir from April 2017 to October 2018 was obtained,and combined with the groundwater quality monitori data,through statistical analysis to obtain changes in water quality.Combined with ground and remote sensing for water quality monitoring,the time interval of water quality monitoring can be shortened,and more detailed water quality changes of the reservoir can be obtained;(3)For the first time,multi-source remote sensing water quality monitoring was carried out in Panjiakou Reservoir and Daheiting Reservoir.The water quality of Panda Reservoir was analyzed by means of remote sensing and ground coordination,which improved the ability to detect risks and traceability of pollution.