A simple method of estimating flash flood peak discharge in a poorly gauged basin
Abstract
This paper presents a simple method for estimating flash flood peak discharge and runoff volume in a poorly gauged basin where the hydrological characteristics of the flood are partially known. Synoptic meteorological analysis reveals the dynamic evolution of severe precipitation events, providing useful information as input to hydrological models. An empirical index is used to generate missing hourly rainfall data and a hydrological model performs the basin delineation, flood simulation and estimates the flood extent. The hydrologic model is calibrated and verified using peak discharge and volume from measured hydrographs of a number of non-flood causing rainfall events. An empirical equation is developed in order to provide the peak discharge as a function of the storm's total precipitation, its standard deviation and duration. The peak discharge for a flash flood case based on the empirical equation, is in agreement with the one calculated via the verified hydrological model and the model based on Manning's equation and post flash flood measurements of the control cross section. This method is successfully applied in the 1994 flash flood event in the Giofiros basin in the island of Crete caused by intense orographic precipitation during which there was a stage gauge failure. The methodology can be tested in other poorly gauged basins facing common stage gauge failures due to severe precipitation storm events.
- Publication:
-
EGU General Assembly Conference Abstracts
- Pub Date:
- April 2009
- Bibcode:
- 2009EGUGA..11.3745T