山梨県内水源池及び湖沼の水質特性と富栄養度

抄録

The water quality and eutrophic state of 3 reservoirs and 5 lakes in Yamanashi Prefecture were investigated. There are 8 artificial reservoirs and 6 natural lakes, i.e. Lake Kawaguchi, Yamanaka, Shoji, Motosu, Sai, Shibire in Yamanashi Prefecture. In order to make it clear whether water pollution problems exist in each lake, the accumulated data of 8 water areas were analyzed in contrast to that of Lake Sagami, which gathers water from Yamanashi and where amusty odor had been detected. According to the modified Carlson's Trophic State Index (TSI) calculated from the transparency and the total concentration of phosphorus of samples, Daimonreservoir and Lake Shoji are the most eutrophicated. In Daimon reservoir especially, the total concentration of nitrogen was equal to that of Lake Sagami. Thus it is necessary to restrict the inflow of phosphorus to avoid water pollution. On the other hand, the total concentration of phosphorus in Lake Shoji was as much as that of Daimon reservoir. As a result, we must control the influx of nitrogen to keep the water quality good.