Dynamic Characteristics And Trends Of Groundwater Level In Hengshui City,hebei Province

Hengshui is one of the cities with the severest water shortages in the North China Plain.This paper analyzed meteorological,hydrological,topographical,geological,hydrogeological conditions and groundwater level dynamic monitoring data of Hengshui City for many years.Based on the local socio-economic conditions,the paper analyzed the spatial and temporal variation characteristics of groundwater level in the study area,summarizes its main influencing factors,and predicts the dynamic trends of groundwater level in the next decade,in order to provide a scientific basis for the rational development and utilization of groundwater resources in Hengshui City.In this paper,first of all,the collected and measured data of groundwater level were statistically analyzed,and the field test,mathematical statistics,numerical simulation and other methods were used to analyze and study the characteristics of groundwater level.The results are as following:(1)Based on the measured and collected dynamic monitoring data of the groundwater level,precipitation,evaporation,topography,current exploitation and other data,the contrast curves of groundwater level burial depth,precipitation and evaporation were drawn.By comparing the characteristics of the curves and the analysis of the changing trends,the dynamic types of groundwater level from 2016 to 2018 were divided into five types.Among them,there are three dynamic types of shallow groundwater levels: precipitation infiltration and groundwater evaporation type,precipitation infiltration and groundwater exploitation type,agricultural irrigation-precipitation infiltration and groundwater evaporation type.And there are two dynamic types of deep groundwater levels: leakage recharge and groundwater exploitation type,runoff-leakage recharge and groundwater exploitation type.(2)Based on the borehole data,the conceptual model,the mathematical model and the numerical model of groundwater flow were established.The numerical model was solved using the finite difference method.The data of 12 observation wells in the study area were used to identify and verify the model.The fitting accuracy was 0.3 ~ 1.5m.The calculated flow field at the end of the recognition period were compared with the measured flow field.They were basically the same.The results showed that the models can more realisticly reflect the actual groundwater flow.(3)According to “Hebei Economic Yearbook”,“ Groundwater Overexploitation Treatment in Hengshui” and“ The 13 th Five Year Plan for Hengshui's Economic and Social Development”,two different groundwater development and utilization proposals were set up.The proposals were used to calculate the dynamic trends of groundwater level.The simulation results are as following.In 2030,the deep groundwater level and the shallow groundwater level will basically restory to the levels of the 1970 s,and the deep and shallow groundwater levels will be basically the same under the first proposal.In 2030,the shallow groundwater will decrease about 2.5m compared with 2018,and the deep groundwater will increase about 10 m compared with 2018 under the second proposal.