Hazards of a flooding event in the city of Gdansk and possible forms of preventing the phenomenon – case study

Abstract

ABSTRACT The main objective is to examine the urban flood hazard in the city of Gdansk and to determine the possibilities of preventing this phenomenon. Hydrological and hydraulic modeling was used for the case study analysis of urban flood in Strzyża basin, applying the HEC-HMS and HEC-RAS systems. The result of modeling with the assumption of torrential rainfall with a duration of t = 1 h (from 35 to 58 mm) is the probability of pluvial flood occurrence divided into low probability (p = 10%), high probability (p = 1%) and catastrophic probability (p = 0.2%). The normal flow of the Strzyża stream at the mouth is 0.175 m3·s−1, while the modeling results indicate an increase in the flow depending on the assumed flood flow probability from about 41.8 m3·s−1 to 54.7 m3·s−1. In addition, the article presents the basic elements of the policy of the city of Gdańsk in the field of reducing the hazards of urban flooding.