On-site stormwater management as an alternative to conventional sewer systems: A new concept spreading in Germany

In Germany a new stormwater management system is spreading across the count ry - the so called "Mulden-Rigolen-System" (MR-System), which may be transl ated as the 'Swale-Infiltration Trench System'. The overall applicable syst em consists of on-site located swale-trench-elements which are connected by throttled sewers to a decentralized stormwater management system. The elem ents are designed and dimensioned in order to allow the highest possible in filtration of stormwater runoff This is obtained by a short-term storage in the grassed swale and a long-term storage provided by the trench. The latt er is formed by highly porous material such as gravel or lava granules, wra pped in geotextile. By infiltration through the active soil layer along the swale bottom, stormwater quality is enhanced up to the quality of drinking water. The MR-System has been applied in many German projects, not only in new developments, but also as a retrofit measure in the existing urban dev elopments. (C) 1998 IAWQ Published by Elsevier Science Ltd. All rights rese rved.