برآورد دبي هاي سيلابي بر اساس خصوصيات هندسي و هيدروليكي مقاطع رودخانه

Estimation of Flood Discharges Based on Geometric and Hydraulic Properties of River Channel

The channel-geometry method is an indirect method of flood estimation, which relies on the development of relations between flood discharges, measured at gauging stations, and channel dimensions, measured from natural river reache in the vicinity of the gauging stations. In this research, a reach from Mehraneh-rud river was chosen. Flood discharges for different return periods were computed by MIKE11, one-dimensional hydraulic flood routing model. The computed hydrographs were routed through the corresponding tributary and adjusted with observed flood peaks at downstream. Finally, channel-geometry regression equations were developed using the river dimensions and related discharges at each section. Developed equations based on logarithmic data had higher distinction coefficient than equations based on normal data. The multi-variable equations had higher distinction coefficients and lower relative estimation error. On the basis of relative error of estimates, results showed the advantages of the channel-geometry method here and in situations where characteristic data were scarce or may not offer appropriate basis for flood discharge estimation.