Hydrological simulations for the Odra flood event 1997

Cord Ruhe1, Ehrhard Raschke2
Institute for Atmospheric Physics, Max-Planck-Strasse, 21502 Geesthacht, Germany.
Tel.: +49-4152-871539, Fax: +49-4152-872020,
E-mail: 1cord.ruhe@gkss.de, 2ehrhard.raschke@gkss.de

The flood event in July 1997 in the Odra drainage basin was one of the biggest and most devastating floods during the past centuries. It was caused by heavy precipitation over the southern part of the drainage basin. Rainfall-runoff simulations for this extreme event with a grid related distributed hydrological model are presented and analysed with regard to operational flood forecast.

This model combines a new land-surface scheme SEWAB (Surface Energy and Water Balance) which calculates the vertical energy and water fluxes between atmosphere, vegetation and soil, with a linear horizontal water transport scheme which transforms the runoff calculated by SEWAB into streamflow. Meteorological forcing for SEWAB has to be provided by observations or operational weather prediction data whereby the latter prolong the forecast time. The model was calibrated for the entire Odra drainage basin (110,000 km2) with data of the time period 199293.

It is intended to integrate the model in the hydrological flood forecast system at the IMWM Wroclaw (Institute for Meteorology and Water Management). In this case the model calculates the inflow to reservoirs and the streamflow in tributary rivers. The flood routing downstream from reservoirs and in major rivers has to be determined with hydrodynamic models.