Abstract
The mixing behavior of turbid water, occurred in 2002 due to Typhoon ‘Rusa’ was numerically modeled with CE-QUAL-W2, a two dimensional width-averaged hydrodynamic and water quality model. On the ground of the modeling results, the horizontal and vertical turbidity distributions right after Typhoon ‘Rusa’ came to the watershed of Imha reservoir, which were hard to figure out using field measurements only, were analyzed on a daily basis. Input data were prepared through the following investigation. The relationship between turbidity in NTU, and suspended solids concentration was obtained through field investigations and laboratory experiments. Water temperature of inflow, air temperature and dew points were compared and their correlation was analyzed. Temporal distributions of suspended solid concentration of inflow were studied when it rained. According to numerical results, the turbid current moved as an underflow up to 12.5 km away from the dam, and after that location it advected horizontally as an interflow towards the dam and also diffused. The time was estimated when the head of the turbid water arrived at the dam.
2차원 수리 및 수질모형인 CE-QUAL-W2 모형을 이용하여 2002년 태풍 ‘루사’의 내습으로 인해 발생한 탁수층의 혼합거동을 모의하였다. 이를 바탕으로 현장측정만으로는 파악하기 어려운 태풍 ‘루사’ 직후의 일별 탁수층의 수평 및 연직방향 탁도분포를 분석하였다. 입력자료는 현장조사 및 실내분석을 통하여 탁도와 부유사농도의 상관관계를 구하였으며, 기온 및 이슬점온도와 유입수 온도와의 상관관계를 분석하였고, 강우시 유입수 부유사농도의 시간에 따른 변화양상을 자료분석을 통하여 구성하였다. 수치모의결과를 이용하여 시간에 따른 탁수층 혼합거동을 분석한 결과, 탁수층은 댐축으로부터 12.5 km까지 저층류로 이동하고 그 지점이후 중층류로서 수평방향으로 이송.확산됨을 알 수 있었고, 유입된 탁수층이 댐축에 도달하는 데 소요되는 시간을 예측할 수 있었다