Optimization Design Of Phreatic Water Level Monitoring Network Of Shunyi Plain

Groundwater monitoring is the long-term basic,public welfare technical work.And monitoring network optimization design is a scientific understanding of dynamic characteristics of groundwater,reasonable evaluation of groundwater resources,developing an effective groundwater protection measures,reducing pollution of groundwater and the associated geological and ecological environment problems.And at the present time,there are some universally existence problems about the groundwater level monitoring network of China including the low density,lack of special monitoring wells and the redundancy of the observation data etc.Although pass through the accumulation of many years monitoring work,Shunyi has already established a set of groundwater monitoring net system,there also exists some problems like the non-uniform of the monitoring stations' distribution.Groundwater is the unique way to discover and identify the process and problem of groundwater,and the groundwater monitoring network is an important part of management work for groundwater.Therefore,it is very necessary to master the groundwater dynamic characteristics and strengthen the dynamic monitoring of groundwater.This paper made Shunyi Plain as the key research area and took phreatic water level monitoring network as research object to optimize the design of groundwater monitoring network.First,in order to optimize the design of groundwater level monitoring network of Shunyi Plain,on the analysis of the existing data and the results of previous studies based,we attributed the factors that affect the dynamic variation of phreatic water to the topography and landforms,permeability,depth of water table,lithology in unsaturated zone and surface water,which the most important is the rainfall infiltration coefficient and artificial exploitation,then analyzed the characteristics of the dynamic change of groundwater levels during the year and many years.Then,considering the types of influencing factors above,this paper introduced a method of groundwater monitoring network optimization design-hydrological geology method.Applying Map Gis,it had drawn the zoning map of the topography and landforms,permeability,depth of water table,lithology in unsaturated zonerainfall infiltration coefficient and water source area,and superimposed to become 99 groundwater dynamic type partitions.Optimization was designed in according with relevant development principles.On the basis of the existing88 monitoring wells,61 new monitoring wells were added.Due to hydrological geology method is a method of qualitative evaluation,and Kriging method is only related to the monitoring wells number,location and layout about,without considering the hydrogeological information,combined the hydrological geology method and Kriging quantitative method.This paper introduced the geostatistics method.According to the water level data of observation wells,calculated the expression:()1.43?h =0.55 h for experimental emi-variogram in Shunyi Plain.Finally,this paper calculated the error of interpolation before and after optimization,which turned from 0.05~1.27 to 0.05~0.59,and made the contour map of standard deviation.The results showed that the value of the interpolation error of the latter one significantly reduced,and within the estimation accuracy,in other words this optimization result was reasonable through the dynamic partitioning method.