Effects of Catchment and Riparian Landscape Setting on Water Chemistry and Seasonal Evolution of Water Quality in the Upper Han River Basin, China

Abstract

Six-year (2005–2010) evolution of water chemistry (Cl−, NO3 −, SO4 2−, HCO3 −, Na+, K+, Ca2+ and Mg2+) and their interactions with morphological properties (i.e., slope and area), land cover, and hydrological seasonality were examined to identify controlling factors and processes governing patterns of stream water quality in the upper Han River, China. Correlation analysis and stepwise multiple regression models revealed significant correlations between ions (i.e., Cl−, SO4 2−, Na+ and K+) and land cover (i.e., vegetation and bare land) over the entire catchment in both high- and low-flow periods, and in the buffer zone the correlation was much more stronger in the low-flow period. Catchment with steeper slope (>15°) was negatively correlated with major ions, largely due to multicollinearity of basin characteristics. Land cover within the buffer zone explained slightly less of major elements than at catchment scale in the rainy season, whereas in the dry season, land cover along the river networks in particular this within 100 m riparian zone much better explained major elements rather than this over the entire catchment. Anthropogenic land uses (i.e., urban and agriculture) however could not explain water chemical variables, albeit EC, TDS, anthropogenic markers (Cl−, NO3 −, SO4 2), Na+, K+ and Ca2+ significantly increased during 2005–2010, which was corroborated by principal component analyses (PCA) that indicated anthropogenic inputs. Observations demonstrated much higher solute concentrations in the industrial-polluted river. Our results suggested that seasonal evolution of water quality in combined with spatial analysis at multiple scales should be a vital part of identifying the controls on spatio-temporal patterns of water quality.

Effects of Land Use, Topography and Socio-Economic Factors on River Water Quality in a Mountainous Watershed with Intensive Agricultural Production in East China

“…TN, DN, NO 3 − -N, TP and DP were higher in the lower part of the basin where more land has been developed and were lower in the upper-eastern part of the Cao-E River basin. Turbidity and EC were higher in the lower part of the basin ( Figure 2 ) where the reach is often affected by tides and/or point source pollution [36], [37].…”

Influence of Landscape Structures on Water Quality at Multiple Temporal and Spatial Scales: A Case Study of Wujiang River Watershed in Guizhou

“…Studies have highlighted land use/landscape within different buffer zones scales. These studies conclude that changes in the spatial characteristics of landscape patterns are a leading factor impacting water quality deterioration [32,34,38,39], the extent and scale of which are case-specific. Research also indicates there is a substantial relationship between precipitation and water quality, as precipitation and surface runoff exert significant impact on flow rates and concentration of contaminants in stream water.…”

“…Such variations are seasonal [1,33,34,40]. Li et al found that riparian land use exerted the largest influence on the upper Han River basin of China during the dry season [39]. However, Shen et al found that landscape characteristics had a strong correlation with water quality during the rainy season [26,31].…”

Influence of watershed topographic and socio-economic attributes on the climate sensitivity of global river water quality

“…The mean elevation of sub-watershed follows the literature while the mean slope gives opposite results. The impact of mean slope on water chemistry varies due to the physical characteristics of the sub-watershed, which includes surficial geology, land use, morphological variables and surficial debris [51,52].…”