Modelling the Effect of Tidal Locking on Flood Risk in Tidal Estuaries

1 IntroductionFlooding is a natural hazardthat can havei mpacts onlives ,communities ,economy and environment . Many coastal regionsaround the UK are vulnerable to sea level rise and cli matechange. Tidally influenced rivers and estuaries can be floodedfr…

Modelling the Effect of Tidal Locking on Flood Risk in Tidal Estuaries

This investigation is to analyze the impacts of sea level rise and changes in fluvial flow on south coast of England. The River Arun was selected as a case study, and HEC?RAS program was chosen as the modelling software in this research. Hydrologic scenarios with combinations of different flow and sea level rise caused by climate change were used. The result shows that the current flood defences are sufficient to prevent flooding at present, but it is likely that a combination of sea level rise and a more active precipitation cycle will cause flooding. The various simulations show that, by constructing sluice gates at the mouth of the River Arun, the flood risk resulting from a 1 in 100 year river flow and sea level rise does not decrease. Indeed, the sluice gates somewhat increase the flood risk. While by selectively removing the flood embankments combining with constructing sluice gates at the mouth, the flood risk decreases. A clear trend of this case study is that the effectiveness of the engineering work drops to zero when sea level rises by a considerable value (say 1.0 m ). The reason for this is that the increase in sea level leads to the rise of tide locked period, and the water stored within the upstream basin will eventually result in flooding.