Hydrogeochemical Genesis And Water And Salt Migration In Wuliangsuhai Watershed

Wuliangsuhai is an important wetland ecosystem protection area in China,which has rich natural resources and plays an important role in regulating climate and resisting desertification.However,due to the rapid development of industry and agriculture in recent decades,especially the lax management of industrial and agricultural wastewater discharge,it has caused serious pollution to the groundwater in Wuliangsuhai and its surrounding areas,and then caused a series of ecological and environmental problems,such as wetland degradation,silt,water quality deterioration and so on.This study takes the basin groundwater-lake system as the research object,through historical data collection,field investigation and sampling,Using the mathematical statistics,the Piper three chart,based on the library's type and the shu card Lev classification,clustering analysis,correlation analysis,Gibbs figure,ion ratio,saturation index relationship of p H,Eh,alkali index,analysis of hydrogeological conditions,groundwater flow field analysis and methods of Darcy's law for different bodies of water,Wuliangsuhai and water chemical characteristics and genetic mechanism The aim of this study is to reveal the hydrochemical characteristics and controlling factors in the Wuliangsuhai Basin at the present stage,to clarify the relationship between groundwater and Wuliangsuhai,and to quantify the role of groundwater in maintaining the stability of the Wuliangsuhai wetland ecosystem.The main conclusions are as follows:1.Both the groundwater in the study area and the water in Wuliangsuhai Lake are weakly alkaline water,and the water quality is generally slightly brackish.The local groundwater is seriously salted and presents brackish water.Due to the influence of strong evaporation and concentration and human activities,there are many types of hydrochemistry in the study area.There are 15 types of hydrochemistry in diving water and 13 types of hydrochemistry in confined water.The dominant ions are all Na⁺and Cl^-,and the types of secondary dominant ions vary a lot.2.The water samples in the study area were divided into four categories by cluster analysis.The A-?-1 water samples distributed in the groundwater recharge area and runoff area were strongly affected by human activities,and the hydrochemical types were relatively complex.The A-?-2 water samples distributed in the southwest of the Desetai Basin near the Wulangsuhai are all soda water type.The buried depth of A-?-3 water samples located in the groundwater discharge area is shallow,and the water chemical components are mainly Cl^-and Na⁺.The hydrochemical components K⁺and Ca²⁺of B-?type 4 water samples located near the farmland drainage canal are generally lower than those of other water samples in the study area,while F^-,As(?),As(?)and iodide are generally higher than those of other water samples in the study area.In addition,during the investigation,it was found that the thick clay layer was found in the process of well formation.Therefore,it is believed that the excess of the above components is mainly caused by the dissolution of clay minerals.3.In the natural state,the formation of water chemical components in groundwater and lake water in the study area is mainly affected by water-rock interaction and evaporation and concentration.Among them,the formation,migration and transformation of hydrochemical components are affected by the leaching process,REDOX process,evaporation and concentration process and cation alternating adsorption in the water-rock interaction.4.The Wuliangsuhai lake is hydraulically connected to the surrounding unconfined water and confined water.In 2019,the unconfined water recharged Wuliangsuhai water volume is about25,091,900 m³ and the salinity is 72,395.95 t(according to TDS).The confined water replenishes Wuliangsuhai lake water volume and salinity,it is relatively small,with a water volume of about 9,098,600 m³and a salt volume of 1,6266.5 t.