Numerical Simulation And Vulnerability Of Water Sources In Xiping County

Groundwater is the main source of exploitation and utilization in northern China.It is indispensable for the reasonable development and utilization of water sources and scientific management.Therefore,this paper relies on the proposed second-phase water source project in Xiping County,Zhumadian City,and uses numerical simulation and vulnerability assessment.Means to predict the dynamic changes of groundwater in water sources.The full text is divided into three parts:the first part is to study the dynamic characteristics of groundwater in water source area by numerical simulation;the second part is to use the index coefficient method based on AHP-entropy weight to study the groundwater vulnerability in water source area;the third part adopts numerical method and regression analysis.The law predicts the equilibrium amount of groundwater in the study area and the allowable production,and puts forward a reasonable mining plan.The following are the main conclusions of this study:(1)Collect the physical geography and hydrogeological data of the study area,analyze the characteristics of the groundwater flow field in the study area,and the relationship between surface water and groundwater;use the Borehole module in the GMS software to build a three-dimensional geological structure model;use the MODFLOW module A groundwater flow model for the study area was constructed.The model identification and verification have been carried out and the accuracy has met the requirements.It can be used to simulate the dynamic characteristics of groundwater flow.(2)Based on the hydrogeological data of the study area,the water source sites were evaluated for vulnerability using AHP method,entropy method,and AHP-entropy weight index coefficient method.The selection of evaluation indicators is based on the actual situation and the strengths and weaknesses of the indicators.These include water depth(D),water richness(R),hydraulic conductivity(C),and air entrainment(I).Seven evaluation parameters such as lithologic zone(A),aquifer thickness(M),and pollution source(P)were established.DRCIAMP model was established as an evaluation system and the study area was based on this model using three methods for groundwater vulnerability.Based on the spatial analysis function of ArcGIS,the vulnerability index distribution is obtained.After comparing,the results show that the vulnerability evaluation method based on the AHP-entropy weight can better reflect the impact of the evaluation sample on the weight itself.The evaluation index is objective and evaluated.The result is reliable.The groundwater vulnerability index is between 4.2 and 8.5,and the vulnerability of the study area is divided into four levels,from the southwest to the northeast,gradually decreasing.Among them,the area with high vulnerability(>7.0)is located in the southwest area of the exploration township.The overall area of 22.51%;the area with higher vulnerability(6.0~7.0)is located in the area along the Tanmiaoxiang-Shuangmiaowang and the county with concentrated human activities,accounting for 19.34%of the total;the groundwater vulnerability is medium(5.0~6.0).The area of Jiaodian-Xiping county accounted for 37.03%of the total;the area of low vulnerability(4.0~5.0)was located in Xulou area,accounting for 21.12%of the total.(3)On the basis of the above conclusions,a prediction was made for the proposed second-phase water source in Xiping County,and two kinds of mining plans were proposed.The amount of allowable exploitation of medium-deep groundwater in the study area was calculated using numerical method and regression analysis method respectively.Reserves were calculated and the results showed that the allowable exploitation of medium-deep groundwater in the study area was 112,000 m~3/d,the groundwater storage in the study area was 211.4 million m~3,and the total groundwater reserve in Xiping County was 725.62 million m~3.Comparing and analyzing two kinds of design schemes,the first one is to protect the long-term exploitation of water sources with the goal of long-term exploitation of the water source while ensuring the quantity of water supply,and has the economic and environmental protection;the second scheme expands the exploitation of water sources on the basis of the first plan.Ensure that the water supply system will not constrain the rapid development of the city in the future,but it will result in the increase of local landing funnels for water sources,and the increased vulnerability of the central location of water sources.Through analysis,the water supply of the two mining schemes is guaranteed,and neither will destroy the dynamic balance of groundwater in the water source area.Based on the groundwater numerical model constructed,the groundwater vulnerability assessment results obtained by model operation prediction and AHP-entropy weight index coefficient method can provide scientific reference for the evaluation of groundwater resources in water sources and sustainable development and utilization of groundwater resources.Provide ideas for local government departments to formulate groundwater resources protection and management policies.