Long-term Equilibrium Calculation And Evaluation Of Groundwater Resources In Harbin

Harbin is an important old industrial base in Northeast China,and 20%of the city's total water supply comes from groundwater.Especially after the water storage of the Dadingzishan Reservoir was closed,it had a greater impact on the regional hydrology of Harbin.Therefore,groundwater resources evaluation should be carried out to find out the status quo of water resources,provide a basis for the comprehensive management and sustainable utilization of water resources in Harbin,and provide a reference for the control of groundwater level in Harbin.Based on the analysis of the background conditions of the study area,the equilibrium area is divided,and the equilibrium elements in the equilibrium area are calculated according to a monthly subperiod,and then the equilibrium result is obtained and evaluated.The underground dynamic analysis is carried out according to the equilibrium result,and the established The mathematical model predicts the groundwater level under different conditions in the equilibrium area,and draws the following conclusions:(1)The calculation and evaluation methods applicable to the equilibrium area are also applicable to the study area.To sort out and select groundwater balance methods,firstly divide the sub-equilibrium area and select the equilibrium period;secondly,determine the equilibrium factors to obtain the changes in groundwater storage?Q and?Q';finally calculate the equilibrium error and evaluate the credibility of the equilibrium result.(2)The strata in the study area are mainly those formed during the Devonian to Paleogene and Quaternary periods,with few intrusive rocks.The main structural unit is the Tianshan-Xingmeng orogenic system.The groundwater types are mainly pore water and fissure water.And karst cave water,groundwater system types can be divided into Xiaoxinganling,Changbai Mountain and Songnen Plain groundwater system areas.(3)The total ?Q'of the equilibrium area is-0.24×10~4m~3/d,the total ?Q is-0.25×10~4m~3/d,the equilibrium error is 6.71,the equilibrium result is reasonable and reliable,and the groundwater is in a negative equilibrium state.(4)After identification and verification,the permeability coefficient is10-35m/d,and the water supply degree is 0.1-0.22.The built model can be used for groundwater forecasting.In the current mining plan,the groundwater level is gradually flattened and the height difference is reduced,but the overall situation is relatively similar;in the expanded mining plan,the groundwater level varies greatly,and the water level mainly falls near each proposed water source,and expanded mining stimulates groundwater resources As the amount rises,the groundwater flow system in the equilibrium zone will gradually reach a new dynamic balance over time.