2College of the Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources
Abstract The results of an integrated study aimed at restoring water quality in a large watershed including seven catchments in north east Iran are presented in this paper. This case study demonstrates how landscape metrics reflect direct or surrogate causes of the land use practices that are the determinants of water quality parameters. Water quality factors included EC, pH, Cl-1, HCO3-1, SO4-2, Mg+2, Ca+2 and Na+1 measured over the period 1988 - 2005. Forty-six spatial metrics of the catchments were computed using available GIS layers and MODIS and Landsat TM imagery. Based on a correlation analysis, the 46 parameters of the catchments were reduced to 14, and these were correlated with the eight water quality factors. Of the catchment variables, 10 were found correlated to water quality factors. Among these, 8 are modifiable and watershed managers should be able to alter these factors to restore water quality. As the first study of this kind in Iran, further applicability of the method and its importance in water quality management through quantitative metrics of landscape is outlined and the procedures to adopt in future studies for proposing restoration actions in the study area is demonstrated.