SPATICAL AND TEMPORAL CHANGES OF SUSPENDED SOLIDS AT NORTHEN WATER AREA IN ISAHAYA FLOOD REGULATION POND

Abstract

 Suspended solids (SS) absorb the organic or nutrimental materials on their surfaces. Thus, it is very important for the adequate water quality management to make clear the temporal and spatial changes of SS in water area. In this study, field observations were continually carried out in Isahaya flood regulation pond to grasp the short- term variation of SS. The measured results show that SS distribute almost uniformly in vertical direction at surface and middle layers. Their concentrations vary with the wind condition blowing over the water surface. On the other hands, high concentration conditions are kept in night wind becomes almost calm. Next, a numerical simulation model was developed and applied to this pond. From the computed results, it is shown that SS distribute with being affected by water flows induced by wind. And the concentration of SS rises at upwind area, because the deeper waters contain high concentration of SS were carried up near water surface by the formation of upwelling flow.