Climate Variability and Change—Hydrological Impacts (Proceedings of the Fifth FRIEND World Conference held at Havana, Cuba, November 2006), IAHS Publ. 308, 2006, 191–195.

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Numerical estimation of flood zones in the Vistula River valley, Warsaw, Poland

MAŁGORZATA GUTRY-KORYCKA¹, ARTUR MAGNUSZEWSKI¹, JAROSŁAW SUCHOŻEBRSKI¹, WITOLD JAWORSKI¹, MICHAŁ MARCINKOWSKI¹ & MICHAŁ SZYDŁOWSKI²

1 University of Warsaw, Hydrology Department, Krakowskie Przedmieście 30, 00-927 Warszawa, Poland

asmagnus@uw.edu.pl

2 Technical Academy of Gdańsk, Institute of Civil and Environmental Engineering, Narutowicza 11/12, 80-952 Gdańsk, Poland

Abstract Flood maps (referred to as flood risk maps) are developed for planning purposes and the needs of insurance companies. They usually map the flood with a 100-year recurrence interval (Q_p1%, i.e. discharge of probability of occurrence p = 1%), or flooding during the largest historically recorded flood. Typically these maps identify the zone of highest hazard, the so-called flood path, which is where construction is forbidden, and a zone of high hazard, i.e. the area between the flood path and the edge of the Q_p1% flood. In this study the assessment of the flood waters between the flood protection dykes of a reach of Vistula River was made using a one-dimensional hydraulic model and a Digital Elevation Model (DEM). The ordinates of water level for the Vistula were determined with the HEC-RAS model, assuming conditions of a steady state flow with a given probability of exceedence. The flood zones obtained from the simulations indicate that a significant part of the town is situated in the potentially dangerous flood hazard zone. The simulations also indicate that under present conditions the elevations of the flood protection dykes are sufficient to convey the Q_p1% discharge. However, the dykes would not ensure protection of an important part of the city in the case of a Q_p0.1% discharge.

Key words flood recurrence interval; flood zone mapping; Warsaw, Poland; Vistula River

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