Tool risk reduction measures


Creation and maintenance of retention areas in urban areas-image

Creation and maintenance of retention areas in urban areas

  • Description
  • Fields of action
  • Synergies
  • Good practice examples
  • References

Retention areas should be placed in the lowest points of urban areas. Surface drainage must ensure that water is diverted towards these areas – preferably on the surface (hollows, streets etc.). Receiving waters and soil needs to be protected from pollution. The realisation of central retention areas is greatly dependent on available space and the topographic condition. Development and zoning plans provide opportunities for implementation.

Fields of action Settlement areas
Additionally to flood risk reduction by slowing and storing surface runoff, the measure has medium or high possible benefits for the following biophysical impacts and ecosystem services: Biodiversity preservation; Climate change adaptation and mitigation; Filtration of pollutants; Recreational opportunities; Aesthetic/cultural value; Increase evapotranspiration; Intercept pollution pathways; Reduce erosion and/or sediment delivery; Create terrestrial habitats

Check out the RAINMAN good practice examples:

no good practice example available


  • Office International de l’Eau (2015): Natural Water Retention Measures, URL: (19.03.2020): detention basins
  • Freie Hansestadt Bremen, Senator für Umwelt, Bau und Verkehr (SUBV) (Ed.) (2015: Merkblatt für eine wassersensible Stadt- und Freiraumgestaltung: Empfehlungen und Hinweise für eine zukunftsfähige Regenwasserbewirtschaftung und eine Überflutungsvorsorge bei extremen Regenereignissen in Bremen, URL: (25.03.2020): Sicherung und Schaffung von Retentionsflächen

Sabine Scharfe, Saxon State Office for Environment, Agriculture and Geology