Main content area

Comparative effectiveness of different infiltration models in estimation of watershed flood hydrograph

Vafakhah, Mehdi, Fakher Nikche, Amin, Sadeghi, Seyed Hamidreza
Paddy and water environment 2018 v.16 no.3 pp. 411-424
computer software, drainage, hydrograph, infiltration rate, land use, models, runoff, soil, soil conservation, topography, watersheds, Iran
The present study aims to evaluate performance of different infiltration models, namely initial and constant rate, soil conservation service (SCS) curve number and Green–Ampt in simulation of flood hydrographs for the small-sized Amameh Watershed, Iran. To achieve the study purpose, the infiltration rates were measured using rainfall simulator in work units acquired through overlaying topography, land use, drainage network and soil hydrologic group maps. All parameters of the study infiltration models were determined with the help of the Infilt. software package. The performances of the models in simulation of the observed output hydrographs from the entire watershed were ultimately evaluated for 28 rainfall–runoff events in the HEC-HMS environment. The different components of the observed and estimated hydrographs including time to peak, runoff volume, peak discharge, discharge values and peak time deviation were compared using relative error (RE), coefficient of determination (R²), peak-weighted root mean square error (PWRMSE) and Nash–Sutcliffe (NS) criteria. The general performance of estimations was also qualitatively assessed using scatter plot and distribution of study variables around standard lines of 1:1 slope. The results revealed that the SCS infiltration model with PWRMSE = 0.61 m³ s⁻¹ and NS = 0.53 performed better than initial and constant rate model with PWRMSE = 1.1 m³ s⁻¹ and NS = 0.54, and Green Ampt model with PWRMSE = 1.35 m³ s⁻¹ and NS = 0.29 in estimation of flood hydrograph for the Amameh Watershed.