Study On Bearing Capacity Of Groundwater Resources In Danling County Of Meishan City

Based on the current situation and characteristics of groundwater resources in Danling County,combined with the background of geological conditions and social and economic conditions in Danling County,and guided by the idea of sustainable development,this paper chooses 10 indicators related to groundwater resources in Danling County,and establishes the index system of groundwater resources carrying capacity in Danling County through the combination of data collation and theoretical research.Then the weights of each index are determined by AHP and Entropy Weight respectively,and the weighted average of the weighted results of the two methods is applied to the comprehensive evaluation of groundwater resources carrying capacity.The main results are as follows:(1)The strata in the study area are mainly interbedded with Jurassic,Cretaceous sandstone,mudstone and sand-mudstone,as well as moraine-glacial water deposit,Alluvial-diluvial deposit and residual slope deposit formed by Quaternary loose deposits.Groundwater in the study area can be divided into pore water of loose rock,shallow weathering fissure water and structural fissure water.The pore water aquifers of loose rocks are Quaternary moraine glacial water accumulation and Alluvial-diluvial sand-gravel strata,which are distributed on both sides of Pengmei Plain and Danling River and Anxi River Valley in Danlingzhen area;the shallow weathering fracture water aquifers are Jurassic and Cretaceous sandstone,mudstone and sandstone-mudstone interbeds,which are distributed in the low mountain areas(Zhangchang Town,Shunlong Township,Shiqiao Township)and in the northwest of the study area.In the hilly area of South Central China(Yangchang Town,Shuangqiao Town and Renmei Town),the structural fissure water-bearing rock group is composed of sand and mudstone interbeds of Shaximiao Formation,Suining Formation and Penglaizhen Formation of Middle Jurassic,which distribute in most of southeastern Yangchang Town.(2)According to the theory of hierarchical analysis,groundwater resources carrying capacity is demonstrated at three levels: target layer,criterion layer and index layer.Groundwater resources carrying capacity indicators include: characterization criterion layer(B1)groundwater resources carrying background indicators are groundwater exploitable resource modulus(C1),water environment capacity(C2),and the proportion of primary groundwater pollution area(C3).Characterization criterion layer(B2)groundwater resources carrying state indicators are groundwater resources exploitation degree(C4),10,000 yuan GDP wastewater discharge(C5),industrial water consumption proportion(C6),industrial wastewater discharge standard rate(C7),groundwater pollution point proportion(C8).Characterization criterion layer(B3)groundwater resources carrying potential indicators are groundwater resources exploitation potential(C9)and groundwater resources utilization potential(C10).(3)Analytic Hierarchy Process(AHP)and Entropy Weight(EN)are used to determine the weight of each index respectively,and the grading and comprehensive grading of each index of groundwater resources carrying capacity in Danling County are obtained by weighted average.The results show that the bearing capacity of groundwater resources in low mountain areas is rated as overload(Zhangchang Town,Shunlong Town,Shiqiao Township);in hilly plain areas,the bearing capacity of groundwater resources is rated as equilibrium or surplus(Danling Town,Renmei Town,Shuangqiao Town,Yangchang Town).