Numerical Simulation Of Groundwater Level Dynamics In The Downstream Area Of The Right Bank Of The Shifosi Reservoir

Groundwater is an important source of water in the northern region,providing important guarantees for local production and life.However,water storage in the reservoir will cause high groundwater levels in the downstream areas,resulting in submerged disasters in local farmland and villages,seriously affecting local agricultural production.Living with residents.Therefore,it is extremely important to study the impact of reservoir water level on the dynamic changes of groundwater level in surrounding areas.This paper collects the relevant data of the study area,applies Visual Modflow software to carry out three-dimensional groundwater numerical simulation research on the farmland of Chenpingpu and Zhujiapu villages on the right bank of Shifosi Reservoir,and establishes a three-dimensional groundwater flow model in accordance with the study area,and predicts three different types of storage.The change of groundwater level in the next five years under the water level,combined with the surface elevation to calculate the immersion area.The main research results of this paper are as follows:(1)Using the hydrogeological data of the study area to establish a hydrogeological conceptual model that conforms to the local actual situation,further establish a mathematical model through data collection and collation,identify and rate the identification model,and test the reliability of the model during the verification period.A three-dimensional groundwater flow numerical model consistent with the actual situation of the local area,through which the groundwater level can be viewed under different time series,which provides a basis for the scientific management of the reservoir.(2)The ARIMA model was used to predict the monthly rainfall and evaporation in the study area from 2019 to 2023.Improve the comprehensiveness of the groundwater level prediction model.(3)Using the verified three-dimensional groundwater numerical model,predict the change of groundwater level in the study area under the different conditions of reservoirs of45.9m,46.2m and 46.5m from 2019 to 2023,and draw the flow field change map of each period.The groundwater level in the study area is discharged from the southeast to the northwest.The higher the groundwater level near the auxiliary dam,the more it is discharged away from the auxiliary dam.(4)The immersion standard is determined,and the difference between the groundwater level and the surface elevation is less than 1.7 m.Based on this,the predicted groundwater level is compared with the surface elevation of the study area to calculate the immersion area.The results show that the immersion area in each period of the year is sorted from large to small: high water period> flat water period> dry season;from the interannual variation,the immersed area increases in each period.When the reservoir water level is 46.5m,the immersed area of each year in the wet season accounts for more than 90% of the total area of the study area.The immersion situation is serious,covering the entire study area;the reservoir water level is controlled in the range of 45.9m to 46.2m.It can effectively alleviate the high groundwater level in the study area and reduce the harm caused by immersion.