Physical influencing factors of groundwater depth in Hotan Oasis

The influences of natural factors on groundwater depth in Hotan Oasis were analyzed by grey relational analysis and multiple linear regression models set up to test the precision of the analysis. The results show that temperature and evaporation are the most important influencing factors of groundwater depth. Groundwater depth sinks deeper with increasing temperature and evaporation. Runoff recharges groundwater and is the second important factor. Groundwater depth gets shallower with increasing runoff and groundwater response lags by one to two months. The influence of wind speed, water temperature or humidity on groundwater depth is relatively low. There is no significant correlation between precipitation and groundwater depth. The groundwater depth regression models have high precision with confidence levels above α = 0.01.