Flood Zoning and Performance of Surface Flow Disposal Channels in the Bandar- Abbas Urban Watershed

The main factors in flooding damages are the natural drainage pattern changing in urban and sunurban areas. The main goal of this research is assessing flood risk; peak flow estimation and efficiency of surface runoff channels in Bandar-Abbas urban watershed and sub basins. For this aim, the digitization of data has been implemented using the GIS which includes drainage density, length of stream, land use type, geology, area and slope. Flood risk ranking was performed by the PROMETEEII model and the peak flow estimated with the Krigger method. Results and outputs show that, according to estimation of peak flow and former experiences, the runoff disposal channels, have are not able to transport flood more than over ten-period return and if a severe flooding occures, the city suffers a damaging flood. The Result of PROMETEEII shows that, Shilat and Sooro subbasin are the highest and lowest risk flood, respectively. Also, the most important criterias in flood risk are the length of stream and drainage density. Therefore, efficient manner are needed to reduce the flooding in urban watershed and improvement of channel system.