Linkage analysis of land use/cover patterns and hydro-chemical characteristics in different seasons in Ebinur Lake Watershed, China

Abstract

Ebinur Lake Watershed, with its oases and deserts, is a typically arid and mountainous region on the northern slope of Tianshan Mountains. Along with ever increasing human activities, agricultural and domestic wastes have been directly discharged into river systems around the Watershed, which consequently poses a grave threat to the sustainable development of Xinjiang. Through statistical and spatial analysis, we have determined the relationships between land use/cover (LULC) and hydro-chemical characteristics during rainy and dry seasons in 2014. Spatial patterns of hydro-chemical characteristics as demonstrated by mineralization, pH, electrical conductivity (EC), and SO42-, HCO3-, Cl-, Mg2+, Na+, Ca2+ and K+ concentrations were examined in 113 sites. Since hydro-chemical characteristics were affected by LULC patterns, this study delineated six zones to analyze the distribution characteristics of hydro-chemical parameters and its relationship with LULC patterns. The results showed that, except for the pH, all variables demonstrated significant spatial differences during dry and rainy seasons. In addition, the relationships between water quality and LULC patterns indicated that the farmland, forest-grassland, water body and salinized land all affected hydro-chemical characteristics during both rainy and dry seasons. Especially, decreased rainfall, irrigation, surface runoff, the area of lake, etc. largely led to the increase in ion content, which had great influence on hydro-chemical characteristics parameters in dry season. Furthermore, we established several stepwise linear multiple regressions models. The results showed that pH, mineralization and Ca2+ were defined by forest-grassland, while the Cl- and Mg2+ were defined by salinized land during the rainy season. The pH and Na+ were estimated based on farmland, whereas Cl- and Ca2+ were estimated based on forest-grassland during the dry season. In conclusion, this research on the relationships between the spatial distribution of hydro-chemical characteristics in Ebinur Lake Watershed and LULC patterns will be significant for the sustainable management of the arid regions in northwest China.

Publication Title

Water (Switzerland)

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