The Evaluation Of Ecological Benefits Of Groundwater Exploitation

Groundwater resources have the advantages of abundant reserves,stable water,and good water quality.At present,it has become an important source of water for sustainable development in many cities in China.However,with the increasing demand for freshwater resources from socio-economic development and the increasing exploitation of groundwater,the groundwater ecosystem has changed,resulting in the changes in ecological benefits.The paper takes the concrete characterization of ecological benefits as the focus and analyzes the impact of groundwater exploitation on the ecological environment,in order to achieve the goals of sustainable exploitation of groundwater and achieve functional stability of groundwater ecosystems.Based on the current status of groundwater exploitation in water-scarce cities in the northern plains,an ecological benefit assessment model was established to provide strong support for curbing the over-exploitation of groundwater resources and avoiding the drop of groundwater level.The paper takes the Hengshui City as a typical area,where is the outskirt of Beijing-Tianjin-Hebei urban agglomeration with serious over-exploitation of groundwater.In combination with the implementation of the comprehensive management action of the groundwater overdrawing area,which is helpful to explore the evaluation methods of ecological benefits of groundwater diversification and enrich the research content of water resources management.Based on the status of groundwater development and utilization in different regions and the economic and social characteristics of the habitat and circulation space,the paper identifies the multiple attributes of the groundwater mining area,such as economy,society,ecology and environment.Based on the ecological perspective,the integrated assessment method is used to explore the value of ecological benefits,and an evaluation index system for the ecological benefits of groundwater exploitation is constructed.The evaluation index system constructed by the dissertation consists of three levels,including 11 indicators.The indicators such as groundwater depth,groundwater resources,groundwater extraction,and groundwater landing funnel area,etc.were selected from three aspects: mining conditions,mining extent,and environmental impact.The paper sets the grade of multiple indicators,such as the ground water quality,ground fissures,land subsidence rate,etc.The AHP and entropy method are used to determine the weights of the indicators.In addition,MATLAB software is also used in the calculation process.After obtaining the initial data of the evaluation index system of the ecological benefits of groundwater exploitation in Hengshui City from 2010 to 2015,the paper made a comprehensive evaluation by using the AHP method.The results show that the ecological benefits of groundwater exploitation in Hengshui City showed a growing trend.After analyzing the monitoring data of groundwater depth from 2007 to 2015 in all districts and counties of Hengshui City,it shows that the shallow groundwater depth is relatively stable while the deep groundwater depth is relatively unstable.The average annual variation of shallow groundwater depth is between 1m.The average annual variation of deep groundwater depth in Jingxian County and Wuyi County exceeds 4m.In the current situation where Hengshui City has a relatively high degree of exploitation of groundwater,it is necessary to strictly limit the exploitation of deep groundwater in the future to realize the coordinated development of groundwater exploitation and economic society.