The surface drainage of roads and properties was planned for an industrial development of around 10 ha on a development area in the East of Hamburg. A special situation was formed in this case by the presence of a cleaned-up contaminated site in addition to part of an old flushing field, high groundwater levels, the location of the development area in a water conservation area with the relevant water conservation requirements in addition to outflow of the surface water into a waterway in a marshy area with low water movement.
Outflow of the surface water took place using ditches which were sealed off to the subsoil using minerals. Before introduction into the waterway, the water is cleaned and stabilised in a naturally-formed rainwater treatment system. The waterway is inside the dyke line so that the requirements of flood protection also have to be considered. Engineering services included planning, invitation to tender and preparation and procurement of the necessary water law and floodwater protection approvals.