Investigation of Regional Flood Intensity in Homogeneous Basins of Kerman Province, Iran

Understanding the flood phenomenon and its effective factors is, the prerequisite of its control and management. This phenomenon is influenced by hydrological, climatic and physiographic factors and it has always been one of the most important issues in hydrology. In this research 94 watersheds with corresponding hydrometric stations with the common period (1976-2011) were selected. Instantaneous peak discharge was calculated with a 50-year return period. 15 hydrological, climatic and physiographic parameters, affecting the flood intensity, including: average altitude, catchment area, Gravelius coefficient, slope, main river length, annual average precipitation, average number of rainy days, base flow index, hydrograph recession coefficient, curve number, permeability and percentage exceedances of, Q2, Q5, Q20 Q50 were calculated for each catchment. Factor analysis was performed after data standardization and the most important independent factors affecting flood intensity were chosen and multivariate regression equations were extracted by stepwise method. Results showed that R2 value of all models were between 82% and 93% and indicates that the models were in good agreement with the data. The first model yields an adjusted R2 of more than 88%. The second, 80% and the third model, more than 91%. The value of predicted R2 of models ranges between 74% and 80%. The Durbin Watson statistic were between 1.81 and 2. The first model yields a standard deviation of 2.1 and the second 1.4 and the third model, less than 2.7.