Revision as of 09:47, 21 June 2010

Uilenkamp - Meander reconnection

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Key features of the case study

Site description

The Vecht river has served as a shipping route in the past. Nowadays it is no longer used for this commercial function. This has made it possible to go from a deep, straightened river to a more natural situation. A first step in this direction was taken by the local water authority with funding of the EU Interreg project. The site of Uilenkamp is a meander that was cut off at the start of the last century to make the Vecht river more suitable for navigation. The banks of the river were fixated and the channel straightened and deepened. This has led to an unnatural channel with relatively few chances for biota to flourish due to the lack of habitat diversity.

Measures selection

To reintroduce natural dynamics and create a more natural river the old meander of Uilenkamp was reconnected to the river Vecht. Bank fixation was removed along the (former) main channel and used to construct a dam that blocks of the main channel during normal flow conditions. This forces the main flow through the reconnected meander and allows for natural processes such as erosion to take place. During peak flows and high water conditions the dam is flooded and water can also flow through the former channel. This measure has led to an increase in river length of 1 km, which leads to increased water retention in dry periods. Also, the water storage capacity of the area was increase. Part of this was done by lowering a nearby floodplain (formerly agricultural land) and digging a number of pools in the area.

Success criteria

• Reintroduction of natural processes
• Increased water retention
• Preservation of flood protection for surrounding areas

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

• Improve water retention
• Improve/Create water storage
• Increase flood frequency and duration in riparian zones or floodplains
• Shorten the length of impounded reaches
• Remeander water courses
• Initiate natural channel dynamics to promote natural regeneration
• Remove bank fixation
• Adjust land use to develop riparian vegetation
• Lower river banks or floodplains to enlarge inundation and flooding
• Reconnect backwaters and wetlands
• Retain floodwater

Related Pressures

• Hydrological regime modification
• Artificial barriers upstream from the site
• Artificial barriers downstream from the site
• Channelisation / cross section alteration
• Alteration of riparian vegetation
• Alteration of instream habitat
• Embankments, levees or dikes
• Loss of vertical connectivity