| Zoucheng City which located in the southwest of Shandong Province,is a county-level city under the jurisdiction of Jining City.In recent years,Zoucheng City exploited a large number of karst groundwater for industrial production and residential water use.and the amount of karst water exploitation in the area is increasing year by year.The main mining organizations are concentrated in Houzhuang-Shuangcun area,has formed a large range of karst water level drop funnel.Over time,it is likely to cause a series of environmental geological problems.Therefore,it is urgent to find a new karst groundwater enrichment area,as an emergency water source for urban water supply,in order to protect the needs of residents living water and industrial water.After the completion of the standby water source,how to rationalize the development and protection of the groundwater resources of the proposed emergency water source,how to divide the groundwater protection area of the proposed water source,and what measures to protect the quantity and quality of the groundwater,will become an imminent problem.In this paper,based on the analysis of the hydrogeological conditions of the study area,the numerical model of groundwater flow in the study area is established by the groundwater numerical simulation software GMS.The simulation period of the model is from 1991 to 2007.Based on the analysis of groundwater balance after identification,the average amount of groundwater rechange in the study area is1.55×108m3/a,and the recharge modulus is 31.89×104m3/km2·a.Among them,the amount of infiltration of atmospheric precipitation is 0.91×108m3/a,which is the most important source of supply,followed by lateral inflow recharge,which is0.35×108m3/a.The main excretion is the phreatic water evaporation and concentrated mining of water sources,respectively 0.55×108m3/a and 0.57×108m3/a.During the simulation period,the groundwater as a whole is in a negative equilibrium state.The cumulative consumption of storage capacity was 4128.8×104m3,and the consumption of karst aquifer storage capacity was 798.08×104m3.The changes of the groundwater level and the storage capacity of the water source under the three groundwater mining schemes are predicted.Taking scheme 3as an example,the karst groundwater level continued to decline at a rate of 2.97m/a in the first five years,and the consumption of storage capacity accounted for 32.03% of the exploitation.after five years,the groundwater level is basically stable,and finally stable at 12.72 m,reached a dynamic balance.The exploitation is mainly derived from the capture of the phreatic water evaporation(72.91%),the excitation of lateral inflow(10.58%)and the consumption of groundwater storage(8.51%).All the mining schemes meet the requirements of the mining constraints,and the mining scheme(Scheme 3)and the maximum allowable exploitation(48,000 m3/d)of the proposed water source are finally determined.Using the formula method and numerical method respectively to delineate the protected area of the proposed water source area,analyze the results of the two protected area delineation methods,and it is concluded that the result of the numerical method is more accurate and scientific,so this study take the results of the numerical protected area delineation method.The primary protected area is 1.27×104m2,the secondary protected area is 0.42km2 and the quasi-protected area is 3.47km2.Combined with the relevant national standards for the protected area delineation,some suggestion were proposed to strengthen groundwater protection of the proposed water source. |
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