The Landsat Data-Based Monitoring of Groundwater Depth and Its Influencing Factors in the Oasis Area of the Weigan River

Using the Weigan River oasis as the research area and based on Landsat and measured groundwater depth data, the temperature vegetation drought index (TVDI) was calculated, and the groundwater depth that was measured in the field was used to establish a groundwater level prediction model (R2 = 0.644). Groundwater distribution in the Weigan River oasis was monitored from 2007 to 2020, and the model was verified using data from September 2013 and June 2015. The results indicate the following: (1) From 2000 to 2015, the groundwater depth of the Weigan River oasis was increased in a fluctuating manner and increased from 2.80 m to 5.79 m, and these values fluctuated sharply with a range of change of 106.79%. (2) The correlation coefficient R2 between the measured and predicted water levels in the two periods is 0.67 and 0.61, and the verification effect is good. (3) In the period from 2007 to 2020, the groundwater depth in the irrigated area exhibited a declining trend, where it decreased from the northwest and northeast to the southwest and southeast. (4) In irrigated areas, the GDP, population, and grain yield exerted a greater impact on groundwater depth. However, precipitation and evaporation were not significantly correlated with groundwater depth.