Land Use/Cover Change Impacts on Water Table Change over 25 Years in a Desert-Oasis Transition Zone of the Heihe River Basin, China

Groundwater resources are becoming the primary factor for maintaining life in arid areas. Understanding land use/cover change and its effect on groundwater depth would enhance land use and groundwater management for typical desert-oasis transition zones. Reduction of groundwater recharge and increase of groundwater exploitation during 1985 and 2010 led to the decrease of groundwater depth in Linze County. The region with groundwater depth less than 5 m decreased by 187 km(2) from 1985 to 2010 as a result of industrial growth, agricultural and economic development. Land use has undergone significant spatial and temporal changes. Farmland and built up land expanded by 53.02% and 30.91%, respectively. The expansion of farmland reached a peak between 1996 and 2005 with an increasing rate of 25.70%, while areas of grassland, woodland, water body and unused land decreased, and the decreasing rate was 9.38%, 58.35% and 19.81%. From 1985 to 2010, the groundwater depth rose slightly (0-1.2 m) in the edge of desert (24.21 km(2)), which was caused by the surrounding farmland irrigation recharge. The drawdown range of groundwater depth between 0 and 3 m was distributed in the central oasis, which was caused by the expansion of farmland and degradation of natural vegetation. This study aims to provide a basis for the reasonable utilization of water resources, the formation of management strategies, as well as to provide ecosystem stability and sustainable development of oases in the study area