The impact of impervious surfaces on ecohydrology and health in urban ecosystems of Banská Bystrica (Slovakia)

The risks of accelerated runoff and its larger amounts brought by urbanisation include increased flood flows and pollution of downstream ecosystems. One of the most significant permanent effect of urban sprawl is soil sealing, which alters natural infiltration and runoff. In addition to imperviousness, the increased runoff from sealed and compacted surfaces results in increased sedimentation of stream ecosystems with contaminants. In most urban planning strategies, water related ecosystems have already become the fundamental components of the integrated urban landscape management, but still have been referred to as objects of protection or rehabilitation; not as management tools. This paper shows how soil sealing significantly affects urban environment and urban ecosystems health. It also demonstrates significant impacts of a city on downstream ecosystems. Data obtained from orthophotomap vectorization showed that the model urban catchment is relatively highly urbanized. 45% of model area is sealed mainly with buildings (40.41%), streets (31.01%), and parking lots (25.28%). Compared to natural basins, urban runoff is 64 times higher and carries a significant amount of pollutants.