Development and application of GIS-based assessment of land-use impacts on water quality: A case study of the Kharaa River Basin.

Abstract

Effective analytical tools, such as geographical information systems (GIS) and multivariate analysis, help to deal with spatial data and complex interactions in watershed management. To investigate the impact of land-use on chemical water quality in the Mongolian Kharaa River Basin, the whole catchment and sub-catchments in relation to each sampling point were delineated. Chemical water quality over three seasons was assessed with GIS and RDA in a modeling approach with forward selection of variables and cluster analysis. The most powerful predictors of river water quality were altitude, settlements, forest, cropland, and distance to spring. In particular, this was true when instead of full sub-basins riparian buffer zones (max. 3km) were considered. From a management perspective, this implies that the protection of riparian zones should be a priority in the Kharaa basin and similar river basins in Mongolia and Central Asia. Because of its positive effects on water quality, forest protection should be closely coupled with river basin management.