Assessment of the effect hydro-physical characteristics of ephemeral streams on the estimation of flood discharges (Case study: Ghollezoo watershed in Kalat Nader city)

This research aims to evaluate the effects of some hydro-physical properties of the ephemeral streams on flood flow estimation. Flood is a phenomenon that damages resources and has always been important to hydrology experts. 

For estimating flood discharge with specific return periods, geometric features of catchment based on rainfall-runoff models are widely applied, which has also been exerted in the present research. In this study, some catchment independent variables related to physiographic features, including drainage area, slope, length of streams, compactness factor, Gravylyus factor, elongation factor, form factor, and land uses, were calculated and extracted at 21 sub-basins. Then, the discharge and specific discharge values with return periods 2, 5, 10, and 25 years were calculated. Also, D50 and D90 were obtained using a sieve gradation (granulometry) graph of geological formations. Then, their relationship with the independent variables of the catchment was assessed by applying multivariate regressions. Then the suitable models were obtained for each discharge return period using SPSS software.

The results showed the variables' variability and importance in determining discharge with different return periods and the necessity of using an appropriate model for estimating runoff resulting from the study basins. 

Based on the findings of this research, it can be said that it is possible to prepare simple and variable models for the estimation of floods with different return periods using simple physiographic parameters. Of course, due to the diversity of climate, Geology, etc., this research's results will differ from the findings in other areas; therefore, it is necessary to perform the same investigations in areas with different characteristics to increase confidence and generalization.

Innovation: 

The most important innovation of this research is the presentation of new models that have not been evaluated and presented in our country so far and can be used to estimate flow and sediment discharge in watersheds with no hydrometric data.