Simulation of the relationship between land use and groundwater level in Tailan River basin, Xinjiang, China

Groundwater is widely recognized as the most significant water resource for irrigation and drinking purposes in the extremely-arid inland river region. However, land use is a major force altering the hydrological processes over a range of temporal and spatial scales. Therefore, understanding the interaction between land use and groundwater processes will definitely contribute to formulate a regional sustainable development strategy and recognize the impact of land use on the groundwater flow regime in the Tailan River basin. A numerical simulation of groundwater level for the inland river basin and scenario analysis under land use using FEFLOW is presented. Spatial data of the regional land use were processed using GIS, and the effects of land use on groundwater level were simulated. The amount of irrigation water and pumped groundwater have the most remarkable influences on groundwater level as main source/sink factors. Their variations were simulated according to the irrigation systems with different crops. Other factors including percolation and evapotranspiration of precipitation and condensed water jointly exerted influences on groundwater level. Changes to farmlands had the greatest impact on Tailan River basin for groundwater level, and unused land and Gobi had the least impact on groundwater level. Groundwater level maintained a decreasing trend in the irrigated zone, and increasing groundwater pumping would further intensify the water shortage in Tailan river basin. This coupled effects resulted from land use and extensive groundwater pumping were considered as the major human-induced factors influencing the groundwater system in the extremely-arid inland river basins. The results can provide useful support for land use. Understanding hydrological processes at the watershed level is essential in land use and water resource planning and management, and the proposed approach can be used as a management and planning tool for evaluating the local and overall impacts of land use management on the surface and groundwater flow regimes.