Estimating storm surge extreme water levels by Monte Carlo and hydrodynamic model in Colombo South Container Terminal Project, Sri Lanka

Gao Feng, Wang Ke Hua, Xu Su-Dong

Friday 3 july 2015

12:30 - 12:33h at Oceania Foyer (level 0)

Themes: (T) Flood risk management and adaptation, (ST) Flooding along in rivers and coasts, Poster pitches

Parallel session: Poster pitches: 15L. Flood Risk - Flooding

Colombo south container terminal project lies at the middle of west coast of Sri-Lanka, west of Bengal Bay. It is influenced by the perennial monsoon climate. Though the high frequency of tropical cyclone, the intensity is weak and wind speed is not high when it passes across Sri-Lanka because Sri-Lanka island locates in the low latitude zone. Different strength cyclones would seriously impact or attack project area, maybe causing heavy surge and enormous losses for harbor engineering. Therefore, it is very important to consider meteorological conditions such as tropical cyclone. The recorded historical water levels in Colombo are not long enough to do the traditional frequency analysis in predicting extreme water levels, such as 50, 100 and 200 year extreme water levels. The numerical simulation approach, can be used when no adequate observational record of flood levels exists. In this study, the potential cyclone storm surge is simulated by the Monte Carlo and hydrodynamic model. According to the probability distribution functions, there are 53 cyclones could have happened in 200 years. A series of cyclone’s parameters for the proposed 53 cyclones are simulated by Monte Carlo. The storm surge water level series are obtained for each simulated cyclone by using Adcirc model. By ranking the maximum water level in each storm surge procedure, the estimation on extreme high water levels as well as low extreme water levels for the desired return period are proposed in this study. The estimated extreme high water levels with return period of 50, 100 and 200 years are 1.25, 1.37 and 1.45 meters correspondingly. The estimated extreme low water levels with return period of 50, 100 and 200 years are -0.09, -0.19 and -0.38 meters separately.