The subject of the present award procedure is the award of engineering services for civil engineering structures for the construction of a new rain overflow basin.

The city of Waldshut-Tiengen operates several mixed water structures for drainage in the Tiengen district. In the area of the Kaltenbach, more and more problems have been identified in recent years. In this catchment area, four rain overflows relieve the small receiving waters of Kaltenbach. In addition, the collector to the sewage treatment plant is overloaded. Therefore, the city is planning the redesign of wastewater disposal in this area.

The city of Waldshut-Tiengen operates a total of eight rain overflows, two rain overflow basins and two reservoirs in Tiengen.

For the realization of a central wastewater treatment, the wastewater association Klettgau West was founded. The neighbouring municipalities of Lauchringen and Weilheim have also joined the association.

The wastewater association Klettgau West operates the wastewater treatment plant in Tiengen. On this site, the wastewater of the districts of Tiengen, Gurtweil, Aichen-Gutenberg, Breitenfeld, Detzeln, Indlekofen and Krenkingen as well as the municipalities of Lauchringen and Weilheim is treated centrally. In addition, the waste water of the districts Ober-/Untermettingen and Löhningen of the municipality Ühlingen-Birkendorf and the district Tiefenhäuser of the municipality Höchenschwand is treated. A connection of the districts of Berau and Brenden (municipality of Ühlingen-Birkendorf) is also planned.

Due to the lack of capacity for the existing demand, the city of Waldshut-Tiengen intends to build a new rain overflow basin in Wutachstraße in Tiengen. For this purpose, the necessary planning services are put out to tender in this procurement procedure.