Study On Hydrodynamic Response Process Of Groundwater Under Artificial Recharge Condition

Groundwater in North China Plain as the main water supply source in the region has made great contributions to social and economic development.However,the groundwater resources in North China Plain have been seriously exhausted due to continuous over-exploitation for decades.Groundwater recharge as an effective means to repair groundwater funnel and restore regional water level has been widely used.In this paper,the experiment of ecological recharge field of Yimu Spring in Baoding area was selected as the object.The groundwater dynamic monitoring,groundwater level data,water sample analysis results and GMS numerical simulation software was used to study the hydrodynamic response process of groundwater under recharging conditions.Come to the conclusion.(1)According to the water level change data of field recharge test and the hydrochemical changes of groundwater,the influence degree of recharge on groundwater gradually decreases with the increase of distance from recharge point,and the large influence range reaches 2km downstream of recharge point.The amplitude of groundwater level in seepage direction is larger than that in vertical seepage direction.(2)By establishing the numerical model of groundwater flow in the test field,the variation trend of groundwater level under different recharge time and different recharge amount is predicted.It is predicted that the variation of groundwater level in the simulated range of the test site under the condition of daily recharge of 50,000 m~3/d for 7 months.The calculation results showed that the maximum increase of groundwater level in the simulated range was 13.3m.The overall rise of groundwater level in the simulated range was 8.4m.It is predicted that the variation of groundwater level in the simulated range of the test site under the condition of three infiltration ponds with the maximum total recharging capacity of 200,000 m~3/d.The results show that the maximum increase of water level at the recharging point is 18.7m,and the average increase of water level in the simulated range is 9.9m.(3)Through the analysis of the test results of the collected groundwater chemical samples,it can be concluded that the groundwater near the recharge point has been obvious effect by mixing during the recharge process,and the concentration of each ion gradually decreases with time.Under the influence of hydrogeochemistry,the concentration of some ionic components in groundwater far away from the recharge point increased,but the overall water quality did not change.(4)The geological conditions at the test site belong to Taihang Mountain single structure aquifer group,and the infiltration capacity is good.According to the field test results,the average daily infiltration capacity of the test site is 55,000 m~3,and the infiltration intensity is 0.6 m~3/s.According to the calculation,the infiltration replenishment coefficient of the test site is 87.02%.Under ideal conditions,the infiltration site can recharge 36.57 million m~3 of underground water every year,which can be used as an ideal artificial recharge site.