Document Type : Research Paper

Authors

• Amin Eidipour
• Mohammad Amin Maddah
• Ali Mohammad Akhoond-Ali

Department of Hydrology and Water Resources, Faculty of Water and Environmental Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran.

Abstract

Prediction of inflow into reservoirs is necessary for reservoir operation during floods, which is important in mountainous watersheds with snow-rain regimes. The objective of this research is to evaluate the GEFSv12 re-forecast data as an input of the HEC-HMS model for forecasting floods due to the extreme precipitation in March/April 2019 in the reservoir of Bakhtiari dam in southwestern Iran. So, ensemble flood forecasting (control and ensemble members) was conducted using extracted precipitation and temperature data with the lead-time up to 10 days. A sequence of predictions for flood warnings was examined when 50% of the members exceeded the threshold inflow of 1000 and 1500 m3/s. The values of the relative volume error for the control member and the ensemble mean of the five days ahead were -15% and -22%, respectively. According to other related studies in catchments with snow-rain regimes, difficulties in flood forecasting were expected in mid- lead-time. But, this study showed that the proposed probabilistic framework could successfully warn of flood events with a lead-time of five days. To cope and predict the flood in Bakhtiari dam with a threshold of 1500 m3/s, the flood warning is issued with a lead-time of 5 to 8 days.

Keywords

• flood warning
• ensemble forecasting
• GEFSv12
• hydrological model
• reservoir operation

Main Subjects

• Water resources management