The Impact of Land Use Change on Evapotranspiration of the Irrigated Areas in Aksu Basin

WANG Zhicheng; LI Zhi; ZHANG Hui; LI Wanjiang; XU Yongjun

doi:10.13522/j.cnki.ggps.2017.0068

Abstract：[Objective]Land use change affects evapotranspiration and the consequent balance between water supply and water demand in a catchment; accurately estimating the evapotranspiration is hence crucial for water resource management. The purpose of this paper is to present a case study on the relationship between land use change and evapotranspiration.[Method]We took the irrigated areas in Aksu Basin as an example and analyzed the impact of spatiotemporal land use change on evapotranspiration.[Result]①Land use change in these areas has been substantial over the past 15 years, with cultivated land increasing at 159.8 km2/per annum. Spatially, the irrigated areas for agricultural production in the catchments of Aksu River, Kumalake River, Tarim River, Wensu and Wushi in Tuoshikan River increased at 37.3 km2 /per annum, 37.2 km2 /per annum, 66.1 km2 /per annum, 4.9 km2 /per annum and 20.0 km2 /per annum respectively. ②With irrigated areas in the aforementioned five catchments surging, evapotranspiration also increased responsively, especially in summer; water loss due to evapotranspiration has been rising at 0.3×108 m3 /per annum over the past 15 years. ③Land use change had increased the evapotranspiration to 244.3 mm/per annum, much higher than the 150.1 mm/per annum for grasslands.[Conclusion ]Global warming coupled with the elevated irrigated areas has increased the demand for water for irrigation and water loss from evapotranspiration simultaneously, exerting unpreceded pressure on the already scarce water resource in this region.