Beneden-Leeuwen - Side channel
Beneden-Leeuwen - Side channel
Key features of the case study
Site description
Beneden-Leeuwen is a site situated along the river Waal, a tributary of the Rhine in the Netherlands. It is characterized by a number of old sand and clay excavation pits and a cut of meander which was part of the Waal river prior to canalization. The floodplain was largely cut off from the main channel due to dikes situated on the banks of the river. The banks are fortified and groynes are in place in the channel. This has led to a decrease in hydromorphological processes and a subsequent decrease in ecological value of the area.
Measures selection
In an attempt to restore the ecological potential of the area as well as fortifying the dikes a deep sand and a clay excavation pit were connected. During high water this clay pit was connected to a former river bend. In years to follow a number of clay pits were dug and three secondary branches were connected, leading to a side channel. This side channel was connected to the main river, creating a side channel which flows with the river during 95% of the time. During low water levels the flow in the channel is reduced by a sill between the sand pit and the channel. The clay that was dug up from the clay pits was used to fortify dikes in the area. These dikes were not yet up to the set national standard. This measure made it possible to both fortify the dikes and at the same time facilitate ecological development of the area.
Success criteria
The project served as a pilot to monitor and analyse the effects. Scientific research was done on the channel to identify if the channel indeed served to (re)create habitat and biotopes that had disappeared due to channelization and artificial alterations of the Rhine and its tributaries in the Netherlands. The primary success criteria in this research were an increase in characteristic wading birds, fish and macro invertebrates.
Ecological response
Hydromorphological response
Monitoring before and after implementation of the project
Socio-economic aspects
Contact person within the organization
Extra background information
References
Related Measures
- Lower river banks or floodplains to enlarge inundation and flooding
- Increase flood frequency and duration in riparian zones or floodplains
- Reconnect backwaters and wetlands
- Construct semi-natural/articificial wetlands or aquatic habitats
