Background: Development of agriculture-dominated socio-economy have led to remarkable increase of water consumption in arid regions of the world. Frequent over-exploitation of water resources resulted in widely environmental degradation in the water-scarce and eco-fragile area, especially in China’s inland river basins. The Shiyang River Basin (SYRB) is the one where the most contradictive situation was found between socio-economic development and environmental sustainability in recent decades. In this study, a case study clarifying groundwater responses to intensive oasis water utilization was conducted during the time period from 1981 to 2010.
Result: Regional AET was stepwise regressed with observed series of T, P and NDVI, the accuracy was found satisfactory. Module analysis revealed that the continuous warming had facilitated the AET rather than the other two factors (P and NDVI). The 30-year statistics revealed that total volume of oasis water utilization far exceeded mountainous discharges in the SYRB. Local abstractions offset the insufficiency and resulted in considerable drawdown of groundwater level. Dynamics of groundwater were found remarkably influenced by land surface water division, oasis scale and water consumption. Driven module calibrated upon regional averages of the above variables, suitable scale of the oasis was quantitatively discussed. Results revealed that the near-complete development of mountainous discharges, along with the over-exploitation of groundwater, have brought about degradation of the underground water system. Groundwater level drawdown showed annual rates of 0.17 m/a and 0.31 m/a in the middle and lower areas, respectively, during the time period from 1981 to 2010.
Conclusions: Overexploitation of water resources and its negative consequences for regional hydrology and ecology in arid regions should be considered as a warning for pursuing economic well-being at the expense of the environment. Given the huge water demand for oasis survival and the background of climatic warming, reduction of arable scale combined with water transfer from outside should be conducted. This study serves as a 30-year case example when above contradictions presented remarkably in inland river systems in the arid northwestern China.