Case study:Lebendige Alster
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Project overview
| Status | In progress |
|---|---|
| Project web site | |
| Themes | Habitat and biodiversity, Hydromorphology, Water quality, Urban |
| Country | Germany |
| Main contact forename | Wolfram |
| Main contact surname | Hammer |
| Main contact user ID | |
| Contact organisation | Lebendige Alster |
| Contact organisation web site | http://https://www.lebendigealster.de |
| Partner organisations | |
| Parent multi-site project | |
| This is a parent project encompassing the following projects |
No |
Project summary
The Alster river is 56-kilometer-long, originates near the community of Henstedt and ends with its estuary into the river Elbe in Hamburg. The best-known part of the Alster is the Alster Lake, which is formed in the inner-city area of Hamburg by the Inner and Outer Alster. Since 2011, the cooperation project “Lebendige Alster” works to improve the ecological condition of the Alster, with its various, sometimes rare, habitats, and to raise awareness of nature conservation. Like many other rivers the impact of urban development is evident in e.g. biodiversity and hydromorphology. Some of these manmade impassable constructions can already be overcome. Due to newly built fish ladders migratory fish can return to the Alster, but then end up in the poorly structured and not very natural area of the canal (Fleet). The absence of natural vegetation confronts many water organisms with difficult living conditions. Here numerous innovative measures to create new living spaces have already been implemented in the canals and the project aims to add more.
During the day, the water in the Alsterfleet is dammed and drained at night, creating strong currents. For this purpose, a “current cocoon” has already been inserted into the canal to create sheltered zones during strong currents. An old typical cargo ship (Grüne Schute) was also rebuilt into a vegetation rich area, where fish and insects can access the Schute through recesses in the ship's side and in the floor. The roots of willow and alder, reeds and aquatic plants offer protection, are hiding places and sources of food. Besides offering positive effects to the surrounding vegetation, the Grüne Schute is also used as an educational venue to allow schoolchildren, citizens and other interested parties to participate in the project and to provide environmental education.
Outside of urban Hamburg, numerous habitat types which have become rare were designed in the first part of the project. A shortage of dead wood, as a result of regular removal, was counteracted with controlled tolerance of deadwood accumulations. Introduction of mobile deadwood as well as installation of individual trees including crowns resulted in improved hydromorphology. The gravel-gap system of the riverbed as an important habitat was supported with the removal of sand, installation of gravel depots on undercut slope areas, narrowing of waters with gravel made flow deflectors.
In addition to the near-natural development of the Alster waters, there are also improvements in local recreation and environmental education.
Monitoring surveys and results
Lessons learnt
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Catchment and subcatchment
Site
Project background
Cost for project phases
Reasons for river restoration
Measures
MonitoringHydromorphological quality elements
Biological quality elements
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Any other monitoring, e.g. social, economic
Monitoring documents
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Additional links and references
Supplementary InformationEdit Supplementary Information
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