The Rastatter Bruch Nature Reserve is a lowland fen situated in the so-called ‘Randsenke’ (peripheral historical side channel) of the Rhine floodplain, immediately on the western outskirts of Rastatt. It is of considerable value in terms of nature conservation and landscape, but has been threatened for decades by increasing desiccation, presumably due to local drainage but also to climate change. Funded by the Baden-Württemberg State Nature Conservation Fund, the project was investigating the area’s conservation status in relation to its water balance, which has been analysed by measurements of precipitation and groundwater levels. In cooperation with the KIT Institute for Hydrology groundwater and local precipitation were modeled under different scenarios. The aim of the project was to assess the area’s water balance and to explore options for improved water management to safeguard the lowland fen, its carbon stocks as well as its plants, animals and habitats. The project also examined the potential arising from the concurrent development of an adjacent 32 ha residential area ‘Muenchfeld and an additional 16 ha ‘Merzeau site’, a former military conversion area: what options exist in the future for synergistically utilising the rainwater runoff from these settlement areas on the high banks to rewet the fen? To this end, research has been carried out in collaboration with the Departments of Hydraulic Engineering, Hydrology and Urban Water Management at the KIT Institute for Water and Environment. Continuous discharge measurements on the run off from the settlements have been applied to quantify the available water volume. The results showed significant amounts of water which would raise the groundwater table of the area by a couple of decimeters – depending on different scenarios used. Significant losses of water - in comparison with the modeled local precipitation - have been attributed to broken pipes in the upstream rainwater drainage system. Water quality was found to be suitable for rewetting the protected fen requiring pretreatment in a retention filter system. Based on this and further data, an integrated concept has been compiled to be implemented within the upcoming development of the area.

Following the project first measures have been taken by installing wooden barrages in the drainage ditches within the fen (clicKIT - Sore Muscles for Peatland Restoration). In addition to that, the municipality is currently developing a management system based on extensive grazing to improve the ecological status of the area.