沈乌灌域深度节水改造前后地下水环境时空变化规律OACSCDCSTPCD

In order to explore the evolution law of groundwater environment before and after the deep water-saving reconstruction in ShenWu Irrigation District,aiming at the groundwater depth,salinity and their relationship,the spatial and temporal changes of groundwater depth and salinity were analyzed by using the method of regional well distribution,positioning and long-term monitoring,and the classical geostatistics theory.The results showed that:(1)After the deep water-saving reconstruction,the groundwater depth in Shen-Wu-irrigated area showed an increasing trend,and the average groundwater depth increased from 1.83 m before the water-saving reconstruction to 3.36 m after the water-saving reconstruction,with an increase rate of 83.9%.The buried depth in the center and south of the irrigation area is larger,and a funnel is generated locally.The maximum buried depth increases to 9.37 m,while the buried depth in the north of the irrigation area changes below 0.6 m.(2)The implementation of the water-saving reconstruction project significantly increased the salinity of groundwater,from 1 296 mg/L before the water-saving reconstruction to 2 634 mg/L after the water-saving reconstruction,an increase of 103.47%.The salinity of groundwater in ShenWu Irrigation District is higher in the southeast and northwest,but lower in the central area.With the implementation of the water-saving reconstruction project,the area of fresh water is gradually reduced,while the area of brackish water is gradually increased.(3)There is an exponential relationship between groundwater depth and salinity in the study area.Groundwater salinity decreases with the increase of groundwater depth,and the coefficient of determination of the two is 0.170 8.From the perspective of space,the area with small groundwater depth corresponds to the high salinity of groundwater,and the area with large groundwater depth corresponds to the low salinity of groundwater,so as to find out the change law of groundwater level and water quality in the irrigation area,so as to provide scientific basis for soil salinization prevention and control.