[01-09-2009] The conversion of land to urban areas has - from the water management perspective - reached its limits. Conventional drainage systems are no longer able to deliver satisfactory outcomes and in view of sustainability principles prove to be inadequate. Due to the extensive surface sealing, municipalities struggle with insufficiency of their drainage systems, which results in frequent flooding and an ever-increasing pollution load of water bodies. Changing climate in the form of extreme torrential rains worsens the condition.