The aim of the Leimbach — Hardtbach — project is to produce 100-year flood protection and, at the same time, significantly improve water ecology in the sense of the European Water Framework Directive. The Leimbach is located between Wiesloch and Oftersheim and has a water length of about 15 km, the Hardtbach is located between Nußloch and Hockenheim and has a water length of about 5 km. The overall project comprises a total of 5 measures, whereby measure 3 is divided into 3 construction phases. Measures 1, 2 and 3.2 have already been implemented. The subject of this procedure is project management services for measure 3.3. This is the expansion of the Leimbach — Oberrun. The project support services for service phases 5 to 9 are awarded according to HOAI. The services to be provided result from the performance profile of the AHO_series No. 9 (5th edition, as of March 2020). Further measures 3.1, 4 and 5 are to be offered as an option.
Action 3.3:
Location: road bridge “In the Weinäckern” to Waldangelbach estuary in the range km 23 + 517 to km 24 + 969.
Activities:
— refurbishment of existing flood protection dams and creation of new dams according to geotechnical specifications in a reversed position to expand the flood drainage profile,
— creating two-sided, driveable entertainment paths,
— water expansion, ecological transformation,
— incorporation of in-stream measures in confined areas,
— Production of ecological patency by redesigning the Wiesloch level and dismantling the former Postmühlenwehr.
Action 3.1 option
Location: Flood rain retention pool (HRB) to the former lift bridge Wiesloch in the range km 21 + 860 to km 23 +270.
Activities:
— widening of the flood drainage profile in the middle section to a length of approx. 350 meters to create an ecological stepping stone for flora and fauna in and around the water,
— incorporation of so-called “in-stream measures” to create flow diversity for the improvement of water structure in the area of the water base, where the cramped conditions allow for reasons of flood protection,
— upgrading and increasing existing dams and embankments. In this section, due to the confined situation, it is necessary to combine it with flood protection walls, especially in the upper section in the area of development up to the expansion line and in the lower section of the wastewater treatment plant,
— creation of entertainment routes on both sides to facilitate water maintenance,
— Departmental insertion of sheet pile walls to secure dams.
Action 4 (option):
Location: flood retention pool in Nußloch to Kirchheim Mühle/km 14 + 742 to 21 +270
Activities:
— lowering the water base between Kirchheim mill and nut hole crash to improve flood protection and as a replacement for dam remediation associated with significant interventions,
— dam backlaying in Nußloch and Sandhausen,
— production of ecological stepping stones in widening areas,
— installation of dead wood or gravel banks in the midwater bed as so-called “in-stream measures” to improve the water structure in the water sole area and to ensure ecological patency,
— remediation of the remaining flood protection dams.
Action 5 option
Location: East from Oftersheim to Kirchheim mill near Sandhausen/km 9 + 791 to 14 + 742
Activities:
Production of a diverse ecological water structure:
— design of a nature-oriented, curved water course,
— development close to natural high perennial corridors and waterside shrubs,
— Establishment of patency by demolition of a sole crash.
Gradual assignment:
Action 3.3:
Stage 1 = basic order:
Basic execution preparation services based on AHO project management performance picture (as of March 2020) and parallel to property planning services Lph 5 to 7 and other special services in accordance with the procurement documents.
Stage 2 = optional services
Basic execution services + project completion based on AHO project management performance picture (as of March 2020) and parallel to property planning services Lph 8 and 9 and other special services in accordance with the procurement documents.
Action 3.1, 4+5:
Optional services, also intended as phased commissioning if necessary. Levers 1 and 2 according to the performance of measure 3.3 including other special services.