Abstract
To resolve problems of water reservoirs such as deterioration of scenic beauty, reduction in aquatic organisms, and odors resulting from advanced nutrient enrichment, and to promote activation of multiple functions of water reservoirs, we carried out field investigations of water quality and bottom mud at Koya Pond, where dredging work was performed as a water quality improvement measure. We attempted to calculate the elusion rate of nutrient salts from bottom mud using a simulated in situ method. Results showed that water pollution is considerable during summer, and that pollution occurs even after dredging, the COD is high at water temperatures greater than 30°C, and T-N and T-P are high at water temperature around 25°C under anaerobic conditions because the elusion of bottom mud is considered to be great. The elusion rate of T-N under aerobic conditions is 1.12-1.33 times higher than that under anaerobic condition, and elusion rate of T-P under anaerobic conditions is 3.01-7.73 times higher than that under aerobic conditions.
