抄録
Typhoon No.21 hit the Japan Archipelago in September 2004, causing landslides and floods in Mie Prefecture. Water muddiness of the in the Miyagawa River persisted for three months. This water turbidity caused concern regarding damage to the ecosystem of the river, the coastal area, and fishery products such as seaweed. Under this situation, we surveyed water quality in the Miyagawa River. Water samples from ten sites were collected six times under the turbid condition, and examined of their water quality. As a result, the COD (chemical oxygen demand), SS (suspended solid) concentration and T-P (total phosphorus) concentration were higher values than those observed under normal conditions. However, the transparency was lower than that under normal conditions. The total nitrogen concentration was similar to that under normal conditions. There were large amounts of phosphorus contained in the particles, although the concentration of nitrogen in the particles was low. There was a significant relationship between the reciprocal of transparency and other pollutant factors such as COD and T-P concentration. Because the handling of the transparency meter is easy, measuring the transparency of river water is a useful method of estimating water pollution in emergencies.
