In Germany a new stormwater management system is spreading across the country - the so called "Mulden-Rigolen-System" (MR-System), which may be translated as the 'Swale-Infiltration Trench System'. The overall applicable system consists of on-site located swale-trench-elements which are connected by throttled sewers to a decentralized stormwater management system. The elements are designed and dimensioned in order to allow the highest possible infiltration 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 latter is formed by highly porous material such as gravel or lava granules, wrapped 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 developments. (C) 1998 IAWQ Published by Elsevier Science Ltd. All rights reserved.
