Water quality in relation to land use and land cover in the upper Han River Basin, China

A total of 42 sampling sites were selected in the riverine network of the upper Han River basin (approximately 95, 200 km²) of China. Over the time period of 2005–2006, 252 water samples were collected and analyzed for physico-chemical variables in order to investigate their spatio-temporal variability in particular the relationship with land use and land cover. Analysis of variance (ANOVA) indicated significant spatial variability in pH, EC, TDS, turbidity, SPM, ORP and nitrogen across the basin. Meanwhile, nitrogen, ORP,I_Mn and turbidity generally displayed higher values in the rainy season. Correlation analysis and regression analysis indicated that water temperature, I_Mn, and nitrogen were significantly related to vegetated coverage, and subwatersheds with higher vegetation cover had relative lower turbidity, SPM, I_Mn, nutrients and TDS. Bare lands had significant influence on nitrogen concentration in the riverine network, implying its large geologic sources in the basin. Percentage of urban area was the predictor for pH and DP, while agricultural land for SPM and I_Mn. The research could provide critical information in sustainable land use practice for water resource conservation for the basin.