Optimization Of Groundwater Monitoring Network Based On GTS Method

Groundwater monitoring network can provide basic information for groundwater research and decision-making basis for groundwater management.The objective of groundwater monitoring network optimization is to obtain the most groundwater dynamic information at the lowest cost and meet the requirements.Reasonable optimization of groundwater monitoring network can provide real-time groundwater information,save monitoring costs,and provide more scientific support for groundwater resource management.Therefore,how to optimize groundwater monitoring network is very important.Taking the groundwater monitoring network in Pinggu District of Beijing as an example,this paper analyzed the characteristics of multi-level monitoring data in different periods,screened monitoring indicators of different aquifer groups,and optimized the monitoring wells of different aquifer groups in time and space by using Geostatistical Temporal/Spatial?GTS?method.The monitoring accuracy and cost are analyzed.The main research results of this paper are as follows:?1?Based on the analysis of geological and hydrogeological conditions and the evaluation results of groundwater quality in the study area,regional monitoring indicators with large index exceeding the standard and obvious trend of change in recent years were screened out,including NO₃^-,F^-,Cl^-,SO₄^2-.As,total hardness,NO₂^-,NH₄⁺are the main monitoring indicators of pollution scale.?2?The genetic algorithm is used to identify the optimal subset of the existing monitoring network,based on the cost of balanced sampling,analysis and maintenance of long-term monitoring?LTM?network to measure the optimality,the spatial optimization of regional monitoring wells in the study area is carried out,including 3 redundant regional monitoring wells and 6 redundant monitoring wells in the pollution source area,with a total removal rate of 13.8%.?3?The monitoring frequency of groundwater monitoring network is optimized.The monitoring frequency of monitoring wells at regional scale is as follows:the monitoring wells of phreatic aquifer group are once per 163 days,the monitoring wells of the first confined aquifer group are once per 181 days,the monitoring wells of the second confined aquifer group are once per 223 days,and the monitoring wells of the third confined aquifer group are once per 265 days;the frequency of monitoring wells at pollution source scale is as follows:the monitoring wells of phreatic aquifer group are once per 104 days,the first confined aquifer are once per 104 days,and the second confined aquifer are once per 121 days.?4?Based on the sampling cost?sampling materials and equipment?,sample transportation cost,water sample analysis?data processing?cost,labor cost?project management?and so on,the monitoring cost are analyzed.The results show that the total cost savings are 29.6%after optimization.