Dynamic Analysis Of Groundwater In Mu Us Sandland And Its Influencing Factors

Mu Us Sandland is one of the 12 major sand areas in China.Under constant governance and transformation,the governance rate of Mu Us Sandland within Yulin has exceeded 90%,and many scholars believe that Mu Us Sandland will soon disappear.However,in recent years,with the urbanization and industrial and agricultural development of Yulin,the demand for water resources in this area has gradually increased,and a large number of groundwater has been exploited.In addition,coal mining has dried up the aquifer,etc.,so the already scarce groundwater resources in this area have become more scarce.In order to protect the fragile ecological environment and realize sustainable development in this area,it is necessary to study and analyze the changing law of groundwater and give reasonable Suggestions.In this paper,taking the sandy land of Yuyang district as an example,based on the local groundwater table buried depth data from 1992 to 2017,the dynamics of sand water level in Yuyang and its influencing factors were analyzed and studied,and the following results were obtained:(1)A time-scale analysis of the water level dynamics in the study area shows that the groundwater level in the study area shows a general trend of increasing buried depth.From1992 to 2007,the water level in each region rose and fell,and the groundwater level is relatively stable.From 2007 to 2012,the variation range of groundwater level in most areas increased significantly.From 2012 to 2017,the decline of water level has slowed down.The years from 1992 to 2007,2007 to 2012,and 2012 to 2017 were divided into weak,strong,and strong periods of decline respectively.(2)Based on the analysis of the groundwater flow field and spatial dynamic changes,the groundwater level in the study area as a whole decreases from northwest to southeast step by step.Meanwhile,the direction of the groundwater flow field outside the ancient channel is basically consistent with the direction of surface water system and flows from northwest to southeast.The groundwater level in the southeast of the study area decreased obviously.With the passage of time,the hydraulic gradient of groundwater in the study area increased continuously,and the groundwater runoff became more intense.From 1992 to 2017,the groundwater level in The Area of Bulanghe Township,Yuyang District was affected by mining activities,forming an obvious descending funnel.The area of the original falling funnel in the eastern area near the southwest of Shenmu County is expanding continuously,so that a large area of regional groundwater level drops.The recharge of surface drainage system to groundwater also changed greatly,and the recharge of the downstream reach of the study area became weak.(3)The amount of groundwater drying in Xiaohaotu station,Hongshiqiao Station and Ephedrine Town was significantly higher than that in other areas,and the significant decrease of groundwater level was determined by human exploitation activities.It is estimated that the total amount of groundwater carding in the study area from 1992 to 2017 is up to 9.143.2billion m~3,with an average annual carding volume of 365.7 million m~3.(4)Groundwater exploitation in the study area is the leading factor causing the decline of the groundwater level,and the correlation between the amount of groundwater exploitation and the depth of the water level is the largest;The correlation of irrigation water to groundwater depth is second only to groundwater extraction.The influences of runoff,air temperature and evaporation on groundwater dynamics in the study area only play auxiliary roles.With the increase of vegetation coverage,vegetation water consumption is increasing.Rainfall has a significant influence on the seasonal dynamic change of groundwater level,but compared with development,it has no significant influence on the annual dynamic change of groundwater level.