Modeling Linkage Between River Water Quality and Coverage / Land Use Using Riparian Zone Approach

Land use/ land cover of watersheds has great impacts on water quality of rivers. The water quality of rivers can be degraded due to changes in the land use/land cover patterns within watersheds as human activities increase. In this study, to determine the relationship between te impacts, which are induced by change in land use/ land cover on water quality, the relationship between land use and water quality variables has been examined. The effects of land use/land cover changes were investigated in different buffer zones. Using geographic information system (GIS) and spatial analysis, 39 watersheds were selected within the southern Caspian Sea Sub-basin, and then the relationship between water quality variables and land use/ land cover classes, in different river buffer zones varying between 30 to 120 meters with 30 m incremental intervals, were examined by Spearman correlation test and multiple linear regression. Due to the fact that two or more independent variables may affect the dependent variable, multiple regression modeling approach was used. The results showed that integrated land use data in intermediate areas could provide the most reliable model for predicting chlorine (R2 = 0.813) and sodium (R2 = 0.77). In addition, in riparian areas with 30 meter, SAR, K, Na, Cl, pH, EC, TDS, Mg, Ca, HCO3 variables had the highest correlation coefficient with their surrounding land use/land cover.