The response of temporal and spatial variability of groundwater level to LUCC in oases in arid areas-a case study in the Sangong River watershed in

Abstract

In this paper, a case study on the impacts of land use/cover change (LUCC) on the temporal and spatial variability of groundwater level in an arid oasis in the Sangong River Watershed located in north piedmont of the Tianshan Mountains, Xinjiang, China, is carried out by using geographical information system (GIS), remote sensing (RS) and geostatistical methods. The temporal and spatial variability of groundwater level in the watershed in 1978, 1987 and 1998 is regressed by using the semivariogram model and Kriging interpolation, the LUCC classification maps derived from the aerial images in 1978, Landsat TM image in 1987 and Landsat ETM image in 1998 are used to superpose and analyze the conversion relationship of LUCC types in the regions with the different isograms of groundwater depth. The results show that the change of groundwater recharge was not so significant in the whole oasis, but the temporal and spatial LUCC was significant whether in normal water periods or high water periods during the 20-year period from 1978 to 1998, and there was a close correlation between them. There was generally a moderate spatial correlation of groundwater level (50.01%), and the spatial autocorrelation distance was 17.78 km. The regions where the groundwater level was sharply changed were also the regions where the land resources were increasingly exploited, which included mainly the exploitation of farmlands, woodlands, construction, industrial and mining lands. The study reveals that the LUCC affected strongly the temporal and spatial variability of groundwater level in the arid oasis, and the study results are of the direct and practical significance for rationally utilizing shallow groundwater resources and maintaining the stability of the arid oasis. c 2005 IEEE. (16 refs.)