Model Simulation of Groundwater Level under the Effects of Land Use in an Oasis

Interaction between land use and water resources is an interactive process, and it is advantageous for the exploitation of water and land resources to quantitatively simulate the interaction process of these two. In this paper, the effects of land use on the change of regional groundwater level in the oasis in the Sangong River Basin, Xinjiang, China are quantitatively analyzed and simulated using GIS and FEFLOW model. GIS means are used to process the various spatial data, such as the data of land use, source-sink terms and boundary conditions, and FEFLOW is used to develop the groundwater model so as to predict and simulate the change of groundwater level. Based on the information of land use in 1987 and 1998 and the measured data of groundwater level during the period from 1987 to 2003, the parameters used in the model are debugged, and the model is revised. The results show that the simulated results are ideal, a gradual drawdown of groundwater level occurs in the urban residential areas in the upstream area of the oasis, and the extent of drawdown of groundwater level is obvious; groundwater level in the downstream area of the oasis is in a slow rise trend. Land use change, especially the expansion of cultivated lands and the long-term land development, was obvious in the central area of the oasis during the period from 1987 to 1998, and there is a certain difference between the actuality of land use change and the predicted result. Expansion of cultivated land results certainly in that the volume of sink terms of groundwater (such as the pumped groundwater and evapotranspiration) is much higher than that of source terms (such as the permeation of irrigation water, precipitation and condensed water), so cultivated land is the uppermost land use pattern affecting groundwater resources.