Research On The Joint Control Plan Of Surface Water And Groundwater In The Rushan River Basin

Groundwater plays an important role in the water supply of Shandong Province.Most of the urban water supply comes from groundwater.However,due to a large amount ofgroundwater exploitation,some areas has formed large-area of over-mining funnel been in,and also caused some environmental and geological disasters,such as seawater intrusion,ground collapse,water pollution and other problems.This study takes Rushan River basin as the research area.Due to the weak conditioning capacity of surface reservoirs in Rushan city,a large amount of water is dumped into the sea even in low flow years.Now,with the acceleration of economic development in Rushan city,the demand for water resources is increasing.The current water resources supply has been no more able to meet the needs of industry and agriculture,and has exceeded the existing water supply projects capacity.Rational utilization and effective protection of water resources is a immediate task.Therefore,it is of important significance to carry out unite planning of surface water and groundwater in Rushan River basin.In this paper,based on the calculation of the water resource supply of current annual and near-term and long-term,and demand balance relationship in Rushan River Basin,the numerical model of groundwater flow is established by using GMS software.After the adjustment of surface water and underground reservoir,the objective function and constraint conditions of linear programming are established.Employing genetic algorithms to solve linear programming equations,a regulatory scheme was proposed for optimizing surface and groundwater resources in each year of the planning horizon,and used the verified groundwater model to predict the change of groundwater level of each scheme,and the rationality of the scheme is confirmed.It has realized the maximum utilization of water resources and achieved ecological,economic and social benefits.The main research results are as follows:(1)After collecting and analyzing domestic and foreign research processes of surface water-groundwater resource joint operation and groundwater numerical simulation,this document takes 2020 as the target year,2025 and 2030 as the short-and long-term planning level year,respectively,according to the "14th Five-Year Plan".According to the national economic development plan of Rushan City,the water demand of current year and near future is calculated.Considering the currently implemented and proposed water conservation initiatives and surface water supply projects,the paper gives the current annual and near term and long-term water supply,and carries on the forecast analysis of water supply and demand balance.(2)By using the data of hydrogeology,hydrometeorology,geomorphology,pumping experiments and other data collected in the Rushan River Basin,the Groundwater numerical model of groundwater flow in the MODFLOW module of GMS(GMS)software has been constructed.The model identification period is from September 2018 to September 2019,and the verification period is from November 1,2019 to May 1,2020.The verification results show that the relative error of the water quantity of source and sink items calculated by numerical simulation and equalization method is small,the calculated water level has a high degree of fitting with the measured water level,and the calculated flow field can basically reflect the trend and law of groundwater flow.Therefore,the established model is stable and reliable,and can simulate and predict the future groundwater level dynamics.On this basis,the regulation and storage of underground reservoir are analyzed and calculated.(3)Based on the analysis and calculation of the available water supply of surface reservoirs in Rushan River Basin,a model for jointly regulating surface water and groundwater was established,with the objective of optimizing economic performance,social optimal and ecological optimal,and the constraints of surface available water supply,water consumption,reservoir water balance and storage capacity,and groundwater balance and storage capacity.The genetic algorithm was used to solve the linear equation,and the feasibility scheme of joint regulation was determined.The four proposed groundwater exploitation schemes were simulated and predicted by the verified groundwater flow model.The prediction period was from January 2020 to December 2030.Based on the analysis and comparison of the trend of groundwater level,the target optimization of the feasible scheme set is carried out,and the optimal scheme of the joint control of surface reservoir and underground reservoir is determined.This research holds immense importance in achieving a rational allocation and utilization of groundwater and surface water in the Rushan River Basin,rationally developing water resources,enhancing the efficient usage of water resources in Rushan River Basin and promoting the healthy,sustainable,and stable development of such resources.At the same time,the conflict between supply and demand of regional water resources can be alleviated and groundwater exploitation can be controlled to achieve regional sustainable development.It can also provide reference for other studies on water resources optimization regulation in coastal areas.