GIS ANALYSIS ON POLLUTANT LOADS IN AN INFLUENT RIVER INTO LAKE TEGANUMA

Abstract

To clarify the cause of pollutant loads in Oohori river, one of the main influent rivers into Lake Teganuma, we have attempted to perform a GIS analysis on pollutant loads in Oohori river. The comparison between the calculalted and observed pollutant loads for COD, T-N and T-P indicates that the calculated results give acceptable agreements with observed results. We also compare the calcuated pollutant loads in 1991 and 2002, showing that the contribution of the domestic waste water appreciably decreases with the increase of extension rate of sewerage and then the industrial waste water and non-point source are relatively dominat. The spatial distribution of the point and non-point sources in the watershed is examined with the GIS analysis.