Geohazards and Geomorphological Setting in Poznań Urban Area, Poland

Abstract

ABSTRACT This paper presents the results of geohazards mapping and evaluation their role in the modifying of the urban landscape in Poznań, Poland. Information on geohazards specific to an urban lowland area (river floods, flash floods, mass movement, wind erosion) because of increasing climate change was compiled into a geomorphological map. The most spatially widespread geohazards in Poznań include: (a) on moraine hills/uplands: mass movement, wind erosion, and flash floods (4.9% of the city area); (b) on outwash plains: mass movement and flash floods (8.6% of the city area); (c) on fluvial landforms: mass movement and river floods (9.8% of the city area); (d) within plains of various origin: flash floods (7.6% of the city area). Mass movement affecting short but numerous (and locally steep) slopes, and flash floods are the most widespread geohazards (16 and 14%, of Poznań’s area, respectively). Extensive urbanisation especially the expansion of impervious surfaces increases the high risk of flash floods.