The Holtemme flood event on 25.07.2017 led to far-reaching escalations and significant flooding in Derenburg. The flood situation was documented in detail and extensively by LHW. As part of the development of the technical basis for implementing the flood risk management directive (EC-HWRM directive) for the Holtemme, the over-flooding areas for the course of the water were determined and evaluated. It was found that the HQ100 outflow as a design outflow for local locations leads to flooding of settlement areas. The weak points for the Derenburg area were recorded in the existing and planning state. Based on their results and local observations, there is a need to review and coordinate the existing plans and derive measures to improve and optimize flood protection at Holtemme and Rothe.
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According to current prioritization, the project includes the implementation of the following measures:
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Rothe
From the height of “In the open fields - glassworks Derenburg” to the confluence with the Holtemme
1. Left-side elevation of the shore line, elevation of the shoreline by raising the Rothe, erection of HWS walls on both sides of the Rothe, reconstruction and construction of the Utzlebener-, Evening- and Wernigeroeder Strasse passages, dismantling pedestrian bridge
2. Production of a Rothe closure structure to protect settlement areas below, including a mobile pumping station
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Hellbach Derenburg
1. Relocation of the junction with the Mühlgraben, Kanalstraße
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Holtemme
1. Production of a Rothe closure structure to protect settlement areas below, including mobile pumping station
2. Construction of a left-sided guide dike above Derenburg
3. Keeping the water cross section clear
4. Strengthening the left-sided shoreline to protect the adjacent buildings
5. Strengthening the left-sided riverbank wall to protect the adjacent buildings
6. Upgrading the right-hand guide dike to protect the adjacent buildings below
7. Strengthening the right-sided riverbank wall to protect the adjacent buildings
8. Strengthening the right-sided riverbank wall to protect the adjacent buildings
9. Strengthening the left-sided riverbank wall to protect the adjacent buildings
10. Raising the bridge Stat. 25+226
11. Strengthening the right-sided riverbank wall to prevent the passage of Holtemme water into the mill moat
12. Production of a closure structure in the mill trench to prevent the backflow of the spars, including mobile pumping station
13. Production of left-sided riverbank wall to protect the parallel road
14. Strengthening the right-sided riverbank wall to protect the adjacent buildings
15. Strengthening the right-sided riparian wall to protect adjacent buildings
16. Raising the bridge Stat. 25+022
17. Strengthening the right-sided riverbank wall to protect adjacent buildings
18. Erection of a bank wall on the left side to protect adjacent buildings
19. Backflow protection of the Rothe passage to prevent the adjacent buildings from flooding, including mobile pumping station
20. Creation of left-sided riverbank wall to protect adjacent buildings
21. Making left-sided riverbank walls to protect adjacent buildings
22. Raising the Stat 24+698 bridge
23. Making right bank wall to protect the parallel road
24. Creation of left-sided riverbank wall to protect the parallel road
25. Production of right-sided riverbank wall to protect the parallel road
The order is placed in 5 performance levels (LS). In LS 1, basic determination and preliminary planning, and in LS 2, design and approval planning, object and structural planning, engineering structures as well as special and additional services are commissioned. Optional services for engineering surveying, geotechnics and nature conservation planning.
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After submission of the approval, LS 3 (optional) includes the commissioning of building and structural engineering structures for the execution planning and preparation of the award as well as special and additional services.
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LS 4 (optional) is intended to commission participation in the award process as well as special and additional services.
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LS 5 (optional) includes site management as well as special and additional services. The assignment of construction surveying is planned as an optional service.
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(Note: The detailed description of the services to be provided can be found in the award documents Part B Statement of Work.)