FLOODMAP DEVELOPMENT FOR URBAN WATERSHEDS WITH RESPECT TO CLIMATE CHANGE

摘要

Urban cities adjacent to rivers are much more prone to flood. This is particularly alarming as more and more people move to these urban cities. This study proposes a scheme to estimate the inundation area and volume due to flood which is useful for flood alleviation measures. The scheme considers a flood-map methodology in determining the submerged area by applying 1D and 2D flow models with the use of GIS. A hydraulic software is applied and then compared with the results from the flood-map model. The scheme is demonstrated on a catchment with a high resolution digital map. The result delineates water level in the channel/river and its corresponding flooded area due to the overland flow. Flooded area and volume can be computed in submerged levels by using spatial analysis - a GIS extension program, presented in a color map suitable for planning purposes. Comparison is made between models and suggestion is offered on computational time, computational accuracy, usefulness of the model in real time forecasting and decision making. Some emission scenarios resulting from IPCC's AR4 are considered; the projected rainfall and sea level form the upstream and downstream boundaries of the catchment under consideration.