Remove bank fixation

Remove bank fixation

General description

Removing bank fixation will reinstate morphodynamics (erosion, sedimentation) in the riparian zone. Artificial substrate used to protect the bank will disappear and the main channel can again migrate laterally. In due course this may lead to more natural width - depth ratio (wider and shallower channels).

Applicability

The applicability depends mostly on the socio-economic functions jeopardised by removing bank protection. It is mostly possible in rural, but hardly in urbanised areas. E.g. in the Netherlands buying buffer zones (15 m along small streams; 75 m along large rivers) from farmers is combined with this measure. When bank erode it does not affect agriculture.

Expected effect of measure on (including literature citations):

• HYMO (general and specified per HYMO element)

Bank removal may contribute to enlarge river depth and width variation and diversify the structure of the riparian zone as well as the structure and substrate of the river bed.

• physico-chemical parameters

This measure has little to no effect on the physical-chemical parameters.

• Biota (general and specified per Biological quality elements

The change in substrate on the bank from artificial to natural has significant effects on all biota. Vegetation - both aquatic and riparian - will develop, while benthic invertebrate and fish species composition will in due course adapt the new habitat conditions (from hard and bare to more soft and vegetated substrate). Eventhough this development is towards a more natural ecological state, indices may suggest otherwise because the artificial hard substrate used to protect bank are quite often populated by rheophilic and lithophilic communities.

Pressures that can be addressed by this measure

• Channelisation / cross section alteration
• Embankments, levees or dikes
• Alteration of instream habitat

Case studies where this measure has been applied

• Asseltse Plassen - Bank erosion
• Lahn Cölbe
• Renaturierung Untere Havel
• Spree - Restoration and remeandering of the Müggelspree - downstream Mönchwinkel
• Lek bij Everdingen - Groyne shields
• Regge Velderberg
• Klebach - Side channel
• Thur
• Dommel Eindhoven
• Ems floodplain (LIFE project)
• Skjern - LIFE project
• River Quaggy, Chinbrook Meadows
• Vallacuera ravine. Removal of a dyke.
• Drava - Kleblach
• Bakenhof - Dyke relocation
• Enns - Aich
• Oberwerries - Optimisation of the pSCI “Lippe floodplain between Hamm and Hangfort” (LIFE05/NAT/D/000057)
• Soest - Optimisation of the pSCI “Lippe floodplain between Hamm and Hangfort” (LIFE05/NAT/D/000057)
• Lower Traun
• Lippeaue Klostermersch
• Ruhr Binnerfeld

Useful references

Surian, N, L Ziliani, F Comiti, MA Lenzi 2 & L Mao (2009) Channel adjustments and alteration of sediment fluxes in gravel-bed rivers of North-Eastern Italy: potentials and limitations for channel recovery. River Research & Applications 25: 551-567