Study On Groundwater Exploitation Scheme Of Suzhou City Based On Multiple Constraints

Suzhou City is located in the northeast of Anhui Province.Yongqiao District is the only municipal district in Suzhou City.It is located at the junction of hills and plains.It is bounded by the Subei Fault,hilly areas in the north and plain areas in the south.Chengxi well field is located in the southern plain area and is currently the only drinking water source in downtown Suzhou.The surface water and diving water in the area are seriously lacking in water quality.For a long time,urban water supply has basically relied on mining medium-deep pore pressure with a depth of 60-90 m,high-intensity mining causes a series of environmental hydrogeological problems.Fuli karst well field is located in the hilly area in the north of Suzhou city.The groundwater development degree is low and the water quality is good.It can be used as an ideal alternative well field,but the exploitable amount is limited.Therefore,how to allocate regional water resources scientifically and reasonably so that the extraction volume can meet the demand without causing hydrogeological and environmental problems is an urgent problem that needs to be solved in Suzhou.Based on the full analysis of regional hydrogeological conditions,water resources conditions,and development and utilization,this paper taking groundwater source replacement as the adjustment direction,and replace part of the mining volume in Chengxi well field with the Fuli well field for mining.According to the different pressure extraction ratios,two optimized mining schemes are proposed,and the water level recovery,water quality safety and water resources balance are set as constraints,by using the numerical simulation method of groundwater flow and solute transport,the evolution process of the groundwater flow field and concentration field formed by different schemes are simulated and predicted,comparative analysis of its environmental effects,and then determine the optimal mining plan,namely:Compress30% of the medium-deep pore water extraction volume in the Chengxi well field,and all replace it to the Fuli well field to extract underground karst water.The results show that,the water level at the center of the funnel in Chengxi well field rose by 4.33 m within 4 years,and then maintained a steady rate of increase of 0.19 m/a,while the water level at the edge of the funnel maintained a rate of increase of about0.07 m/a after a slight decrease.The area of the drop funnel with a water level of less than 5,10,and 20 m has been continuously reduced,and the water balance in well field has changed from a negative balance to a positive balance,and the surface water has the smallest degree of pollution to the water quality of the medium-deep groundwater.Although the continuous exploitation of this scheme in the water source area of Fuli will cause the water level to drop more rapidly,the rate of decline in the later stage will also stabilize,and no new environmental hydrogeological problems will arise.The research provides a scientific basis for the rational development and utilization of water resources in Suzhou City,as well as a thinking and reference for groundwater management research in the vast northern region.