Influences of Landscape Configuration on River Water Quality

Abstract

The present study investigated the effects of changes in landscape configuration on river water quality, which is calculated by chemical export coefficients, using spatial data onto 31 catchments in the southwestern part of the Caspian Sea basin by applying stepwise multivariate regression models. The water quality modeling has been carried out applying the chemical export coefficients of sulfate, bicarbonate, chlorine, calcium, magnesium, and sodium, and eight landscape metrics (including interspersion juxtaposition index, percentage of like adjacencies, aggregation index, clumpiness index, normalized landscape shape index, patch cohesion index, landscape division index, and splitting index), by which landscape configuration is analyzed. The results indicated that the sulfate (0.25 ± 0.33 gr ha−1yr−1), bicarbonate (0.61 ± 0.87 gr ha−1 yr−1), chlorine (0.17 ± 0.23 gr ha−1 yr−1), calcium (0.16 ± 0.21 gr ha−1 yr−1), magnesium (0.05 ± 0.07 gr ha−1 yr−1), and sodium (0.16 ± 0.21 gr ha−1 yr−1) are annually exported from the study catchments into the rivers. The change in landscape configuration has significantly explained the chemical export coefficients of sulfate, bicarbonate, chlorine, calcium, magnesium, and sodium. The findings showed the cohesion and coherence of the permanently irrigated land patches resulting in the discontinuity of the broad-leaved forest and grassland ecosystems degraded river water quality.