More than twenty locations on the Wipper will protect a new flood retention basin from flooding. The ecologically consistent structure can retain up to 4.25 million cubic meters of water. Tractebel Hydroprojekt GmbH has been working as a general planner for this ambitious dam construction project since 2013 and oversees the construction.
Many villages along the Wipper suffer from flood events. The losses of recent years amount to a double-digit million amount. A new retention basin, which is passable for fish and other creatures, will remedy this situation. The project is a building block of the flood protection concept for the Wipper, which covers a catchment area of 621 km² up to the mouth of the Saale above Bernburg. At the upper reaches of the Wipper, directly above the village of Wippra in the district of Mansfeld-Südharz, the controlled flood retention basin (HRB) is created with an ecologically continuous passage structure. In 2013, the dam company Sachsen-Anhalt commissioned Tractebel Hydroprojekt GmbH with the general planning for the new building of the HRB Wippra from the execution planning. The hydraulic engineering experts at Tractebel Hydroprojekt optimised the present design and prepared the execution and tender planning for four lots. Model tests at the Technical University of Nuremberg confirmed the hydraulic function of the solution, which the team recommended for the complex passage structure.
The main work began in June 2014 and lasted until the end of 2019. The ceremonial start of construction with the laying of the foundation stone took place in the presence of the then Environment Minister of Saxony-Anhalt Hermann Onko Aeikens and other representatives from politics, administration, planning and the construction industry on September 23, 2014. Various preparatory measures preceded the start of construction, including the replacement construction of the Wippra bridge, the demolition of the old Wippra waterworks, logging work, woody planting and species protection measures. The new barrier structure consists of a dam with a culvert structure in which the service outlets and the spillway are integrated. The top of the dam is 17 m above the valley floor and is 190 m long; the base of the dam measures 120 m wide. Around 8,000 m³ of concrete and reinforced concrete as well as 1,600 t of reinforcing steel were used here. The rockfill dam with inclined inner seal consists of 150,000 m³ of fill material. The retaining body material comes from a newly developed nearby quarry in the valley of the Wipper river. Tractebel Hydroprojekt prepared the stability verifications and planned the rock support. The team of experts was also responsible for geotechnical construction supervision, including metrological monitoring. With the handover of the trial impoundment program and the provisional operating regulation, it clears the way for the planned commissioning of the basin in 2020.
Lars Schaarschmidt, Steffen Hagenloch – Weimar