| Dengkou County is a typical arid area,belonging to the overlapping area between Hetao Plain and Ulan Buh Desert.In recent years,Dengkou County has a strong wind erosion,low precipitation,and a large amount of evaporation which leads to a shortage of water resources and land desertification.In view of these ecological problems that need to be solved,based on the theoretical basis of the strong dependence of ecosystems in arid regions on groundwater,this paper uses GIS technology and geostatistical theories to study the temporal and spatial distribution characteristics and changing rules of groundwater depth in Dengkou County.Combined with the research results,the main influencing factors of the spatial-temporal variation of groundwater depth in the study area are discussed.It is of guiding significance for the protection and development of groundwater resources in Dengkou County,and accelerating the construction of ecological civilization.The main research results of this paper include the following contents:First of all,through consulting the literature at home and abroad to understand the influencing factors of groundwater depth in arid areas,we obtained data on vegetation,hydrology and meteorology in the study area through remote sensing inversion and field surveys.By correlation analysis,factors with high degree of correlation including NDVI and evapotranspiration were selected as co-kriging interpolation covariates to ensure the range and accuracy of interpolation.Secondly,this paper collates the groundwater depth data of the Dengkou County in 6 years(1990,1995,2000,2005,2010,and 2015)and obtains the data of groundwater depth for 40 observation wells.Co-kriging interpolation method was used to apply the geographic information system software ArcGIS to draw spatial distribution maps of groundwater depth in different years in the study area.The spatial distribution characteristics and interannual variation of groundwater depth were analyzed for many years.This research collated the groundwater depth data of 6 years in the Dengkou County in the 25 years,and obtained a complete 40-well observation data of groundwater depth.The geologic statistics was used in conjunction with the co-kriging interpolation method,and then the geographic information system software ArcGIS was used to draw the spatial distribution map of groundwater depth in different years in the study area.This paper focused on analyzing the spatial and temporal distribution characteristics and changing rules of groundwater depth over the years.Finally,the spatial distribution of groundwater depth was expressed in three dimensions,and the dynamic changes of groundwater depth over the years were intuitively understood.Combined with the characteristics of the natural environment and the changes in the local people's activities in the study area for many years,this paper discusses the influence of natural and human factors on the spatial and temporal distribution of groundwater depth.Based on this,the paper proposes the rationalization of the sustainable development and utilization of groundwater resources.According to the above findings,it was found that a groundwater funnel formed in the desert area in the south of Dengkou County with the highest buried depth.The ratio of groundwater depth of 1.8-2.7m showed a decreasing trend,while the depth of 2.7-3.5m and 3.5-4.5m depth of the ground generally showed an upward trend,and the depth greater than 4.5m generally showed a downward trend.In 2005,the maximum depth of groundwater fluctuated and until 2010-2015,the situation had been restored to a stable level.Through the analysis of the causes of the spatial-temporal distribution of groundwater depth in 25 years,it was found that precipitation and surface water have different effects on groundwater depth in different regions and seasons.In addition,human factors have a greater impact on groundwater depth. |
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