Study On Aquifer Regulation And Storage Capacity Of Groundwater Funnel Areas In North Weifang

In recent years,due to the excessive exploitation,a large range of groundwater drawdown funnel was formed in the northern Weifang City,and the funnel areas have a continuous water storage space.It is easy to cause environmental geological hazards and ecological environment damage caused by ground subsidence,ground fissures,saltwater intrusion,water environment pollution and so on,meanwhile,due to the continuous decline of groundwater level,it is easy to accelerate the infiltration rate of surface sewage and increase the groundwater pollution.However,we can make full use of these spaces to build underground reservoirs.In the period of water storage,the water resources can be utilized in the dry season.In this way,not only can control the groundwater level decline,curb funnel development;and full storage and utilization of water resources,reduce the surface water in the reservoir exposed to the surface to a large number of resource waste caused by the evaporation.In this study,we collected the social and economic conditions,physical geography,groundwater overdraft,hydrogeological materials and analyzed the geological structure to partition the hydrogeological units.Meanwhile,we chose the representative drills and drew the profiles to describe the spatial distribution of aquifers.According to the soil fraction,the underground space was divided into the permeable layer,the weak permeable layer and the impermeable layer.The groundwater system consisted of phreatic water(shallow groundwater system),faint confined groundwater and confined groundwater(deep groundwater system).Finally,the storage capacity was calculated by the formula of unconsolidated rocks.The storage capacity of underground reservoir refers to the void volume of groundwater reservoir.The calculation of storage capacity only takes account of the volume of gravity water stored in these spaces,excluding the volume of the medium.In this paper,three methods are used to calculate the storage capacity and make a comparison.The 3D model of underground reservoir was plotted by GMS.The basic principle of the use of underground space is to use the underground water in the dry season,extract the groundwater beyond the natural runoff,vacate the underground storage space(i.e.underground reservoir storage capacity),so as to obtain water resources needed in dry years or dry season.During the period of abundant water season,the underground water storage space is filled again by natural recharge or artificial recharge.Through establishing the comprehensive evaluation index system of underground reservoir storage capacity,the grey correlation analysis of the index system is made,and the index is reduced to seven to evaluate the storage capacity of underground reservoir.Seven indicators were: the maximum storage capacity,storage layer conductivity,average precipitation under the current conditions of years,average annual runoff,average annual exploitation resources,hydraulic discharge of a single well,groundwater recharge resources.Then,by using projection pursuit to evaluate the storage capacity of the north,Hanting,Changyi and Shouguang.Finally,this paper analyzed the benefits of groundwater storage.We build the underground reservoir to store water,at the same time with economic efficiency,resource efficiency,environmental benefits and social benefits.This study provided technical support for groundwater utilization in Weifang.