The drainage system in the Moorfleeter Straße was checked to ensure that it conforms with the currently applicable water conservation laws during the course of modernisation. Investigations were made into whether drainage of the rainwater sewer with an outlet in the Billbrook canal require adaptation for reasons of water conservation requirements. The high levels of traffic along the Moorfleeter Straße cause increased pollution of the surface water which meant that water treatment facilities in acc. w. DWA – M153 were urgently required after investigation of the water pollution levels.
A range of different variations for rainwater treatment were developed for the 41 ha catchment area. This could not be provided underground due to the size of a regular sedimentation basin, which allows polluting water constituents to sediment through gravity. Construction of the basin above ground was also made impossible by the lack of hydraulic gradients. In the end a special structure made of sheet piling profiles and covering an area of 420 m² was developed in front of the outlet into the Billbrook canal. After consideration of costs for construction and the follow-on costs for maintenance of the facilities, several decentralised facilities adapted to the relevant road sections were planned instead of one central treatment works.