Groundwater Resources Evaluation And Research In The Lower Reaches Of Futuan River In Rizhao City

Futuan river is the largest river flowing into the sea on the coast of Rizhao City,and there are four groundwater sources in the lower reaches of the river,which are Ezhuang water source,Quhekou water source,Dingjialou water source,Hetao water source.Futuan river water sources is the main drinking water source with water supply in Rizhao City and preliminary investigation of groundwater resources was made in the early 80 s.With the change of natural conditions and the intensification of human activities,the reduction of groundwater resources and the deterioration of groundwater environment have greatly changed the regional hydrogeological conditions.There are some geological problems in the study area,such as the local groundwater level drawdown funnel,the southeast coastal water intrusion and the phreatic aquifer.Therefore,in order to protect the Futuan River downstream of Rizhao City water supply safety,and provide scientific basis for sustainable utilization of water resources security,assessment and prediction is of practical significance for the groundwater resources in the lower reaches of Rizhao City Futuan river.In this paper,the groundwater resources in the lower reaches of the Rizhao City River are evaluated,and the recharge quantity is calculated by using the equilibrium method and the numerical method.The evaluation process of the strata in the study area 3 dimensional model,combined with the hydrogeological conditions of the study area,generalized hydrogeological conceptual model,mathematical model is established,and then with the help of Visual Modflow to establish the regional scale groundwater numerical simulation model,taking the underground water level observation value and the fitting degree of calculated value as the index,through the recognition model each partition inversion of hydrogeological parameters,and verified the model further confirm its rationality.On the basis of the above work,the seawater intrusion process model is established,and the model forward prediction is carried out.Through the evaluation and research of groundwater resources in the study area,the following results are obtained: The chemical characteristics of groundwater in the study area show obvious zonation from recharge area to drainage area,with water quality types of HCO3-Ca,HCO3-Ca·Na,HCO3· Cl—Ca·Na,HCO3·Cl—Na,Cl—Na.In current year,the amount of groundwater recharge is 1.601?105 m3/d,with precipitation recharge of 8.057?104 m3/d while groundwater discharge is 1.491?105 m3/d with groundwater withdrawal of 5.30?104m3/d.By using the groundwater model to predict the three scenarios,the corresponding trends of groundwater flow field and seawater intrusion are obtained.By using the groundwater model to predict the three scenarios,the corresponding trends of groundwater flow field and seawater intrusion are obtained.The prediction results show that setting barrage can slow down but cannot fundamentally solve the problem of seawater intrusion problem.The solution is to control the exploitation of groundwater in coastal areas and make rational use of underground water resources.