Groundwater Vulnerability Assessment And Development Targets Selection As Emergency Water Sources In Sanming City

Nowadays,water resources have been regarded as rare and precious resources and in some places they have even become strategic resources.For Fujian Sanming Ecological Industry and Trade Zone,surface water is the main source of water supply,and groundwater is an important supplement.However,due to surface water is easily polluted by industrial and agricultural waste water and the long-term interaction between surface water and groundwater,it is necessary for us to grasp or ascertain the characteristics and vulnerability of groundwater in the Sanming Eco-Industry and Trade Zone in order to consider the possibility of using groundwater sources as emergency water supply under extreme water pollution incidents or drought conditions,and then ensure the coordinated and sustainable development of the local social economy and ecological environment.Based on these,the characteristics and vulnerability of groundwater in Sanming Eco-Industry and Trade Zone are studied and the suitability of establishing emergency water sources in the area is analyzed and evaluated for Determining development targets selection which can be built the emergency water source in this paper on the basis of participating in the Sanming Urban Water Resources Evaluation and Emergency Water Source Planning Geological Survey Project.The main work is as follows:Considering that the study area is mainly hilly and low-mountain,land use has a great influence on groundwater.Therefore,extremely important land use factor is supplemented in the evaluation indexs to form an eight-factor vulnerability evaluation system,and an improved DRASTIC model is established.Then three indicators of water quantity,water quality,and geological disasters are selected to evaluate the suitability of emergency water sources.The weight distribution is optimized by using Analytic Hierarchy Process(AHP)and single-parameter sensitivity analysis method.The Spearman rank correlation coefficient is used to analyze the correlation between groundwater nitrate concentration and vulnerability in order to verify the groundwater vulnerability assessment results.On this basis,the groundwater vulnerability zoning map and emergency water source suitability zoning map are drawn,and the regional groundwater vulnerability and emergency water source suitability grades are given,and based on the combination of the two,the emergency water source distribution plan is generated to clarify the plane locations and mining horizons of the development targets selection.The research results will provide a scientific reference for the planning and utilization of groundwater resources in government departments or enterprises.Research indicates:(1)The low groundwater vulnerability areas accounts for80.53%,the medium areas accounts for 17.63%,and the higher areas accounts for1.84%.In general,the overall vulnerability level is low.The central urban areas and the banks of the Shaxi River are more vulnerable.The evaluation result is verified by calculation of Spearman rank correlation coefficient,which is medium correlation,and the evaluation result is credible.(2)Suitable areas,more suitable areas,basically suitable areas,less suitable areas and unsuitable areas in the emergency water source suitability evaluation respectively accounted for 10.41%,12.45%,17.60%,31.30%and28.24%.Generally speaking,suitable areas are mainly distributed in areas with abundant water,good water quality,and convenient transportation close to the urban area without obvious geological disasters.Through single-parameter sensitivity analysis and verification,it is found that the actual effects of allowable production,groundwater vulnerability,and single well water inflow are all greater than expected,while the actual impact of aquifer thickness and Karst collapse indicators is slightly less than theoretical estimates.The final effective weight is basically the same as the theoretical weight,and the result is credible.(3)The development targets selection for emergency water sources in the study area are divided into two types:key targets selection and general targets selection.There are three key targets selection,which are distributed in the Yongan Qingshuichi-xiaha Zone,Sanming Sangang-Liexi and Taixiban Zone.The lithology of the mining aquifer is mainly the limestone of the Qixia Formation and Chuanshan Formation and the water supply can reach more than 10,000m~3/d.There are eight general targets selection,among which the water sources are located in Yikou,Kengbian,Dongpo of Yongan,Youxi of Fukou Town and Sanming Chengguan-Fuxingbao belong to the carbonate fissure Karst water-bearing rock group and the depth of groundwater is deep.The mining target horizons are limestone of the Qixia Formation or Chuanshan Formation.The water sources in the areas of Jingdong-Xinkou,Yanqian-Wulong and Langkou-Houdi belong to the vein-like structure fissure water-bearing rock group.The depth of groundwater is shallow.The Permian Wenbishan Formation,Changlin Formation and Cuipingshan Formation are the main Mining horizons.There are 32 figures,10 tables and 84 references in this paper.