The effects of land use on river water chemistry in a typical karst watershed (Wujiang River) of southwest China have been evaluated. Dissolved major ions and Sr isotopic compositions were determined in 11 independent sub-watersheds of the Wujiang River to investigate the spatio-temporal variations in river water chemistry and their relationship to land use. The results show significant spatial variability in pH, major ions, total dissolved solids (TDS), and Sr isotopic compositions throughout the basin. Correlation analysis indicates that nitrogen content is significantly related to forest coverage. Nitrogen and potassium generally have higher values in the rainy season, and the percentage of agricultural land controlled NO3- levels, which originate from anthropogenic sources. Forest cover, which varies between 35% and 71%, has no statistically significant impact on river solute concentrations, but the TDS flux is low in sub-watersheds with greater forest cover. Geological sources have a significant influence on pH and Sr isotopic compositions in river water throughout the basin.

Publication name	HYDROLOGICAL SCIENCES JOURNAL-JOURNAL DES SCIENCES HYDROLOGIQUES, 59 (5):1063-1073; 2014
Author(s)	Han, Guilin; Li, Fushan; Tan, Qiu
Corresponding author	HAN Guilin  hanguilin@cugb.edu.cn  China Univ Geosci Beijing, Sch Water Resources & Environm, Beijing 100083, Peoples R China.
Author(s) from IGCAS	LI Fushan

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