Analysis of relation between water quality according to chemical indexes and water catchment area use

Catch basins for a number of the rivers of Vologda region were framed using ARCGIS 10, method Hydrobiology, and their usage was assessed. Parts of catchments for 11 small and medium rivers with different anthropogenic stress were analyzed. The area of each catch basin was divided into 3 categories: little-developed, agricultural and urban ones. For 3 city rivers 2 categories were analized. The data on catchment area use were recorded for all sites from satellite image with ScanEx Image Processor. Areas of 3 land-use types (forest, agriculture, and urbanized terrain) were calculated. Forest on the parts of catchments composed from 12 to 100%, urbanized terrain composing from 0 to 51,5 %. Areas of differnt categories were compared with hydrochemical indexes of water quality. Indexes of water quality showed strong positive correlation with the areas of urbanized terrains on the parts of catchments (0,81-0,95),but weak correlation with areas of agriculture (0,62-0,8). As for the forest areas, they showed strong negative correlation (-0,75…-0,9). Indexes of water quality were sensitive to negative anthropology influence.