Natural areas are often converted into paved or sealed surfaces. The degree of surface sealing,
public transport and hydrotechnical infrastructure significantly alter the rainfall-runoff
relationship in the area. All these factors entail consequences which often result in numerous
and severe floods. The paper assesses the impact of surface conditions on the size of storm water
runoff from both natural and urban area and the impact of seals on land runoff hydrographs.

Natural areas are often converted into paved or sealed surfaces. The degree of surface sealing,
public transport and hydrotechnical infrastructure significantly alter the rainfall-runoff
relationship in the area. All these factors entail consequences which often result in numerous
and severe floods. The paper assesses the impact of surface conditions on the size of storm water
runoff from both natural and urban area and the impact of seals on land runoff hydrographs.