Difference between revisions of "Lek bij Everdingen - Groyne shields"
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| − | To avert the disturbance in the water flow caused by passing ships a number of groynes were shielded off by artificial structures placed in front of the groynes. These structures were made of two rows of wooden poles with branches in between them. The reasoning behind this measure was that the coils in the water would be stopped by these poles and a more suitable habitat, primarily for macrophytes, would be established in the groyne fields. The presence of macrophytes would in turn increase habitat availability for fish and | + | To avert the disturbance in the water flow caused by passing ships a number of groynes were shielded off by artificial structures placed in front of the groynes. These structures were made of two rows of wooden poles with branches in between them. The reasoning behind this measure was that the coils in the water would be stopped by these poles and a more suitable habitat, primarily for macrophytes, would be established in the groyne fields. The presence of macrophytes would in turn increase habitat availability for fish and benthic invertebrates. Benthic invertebrates were thought to also be able to benefit from the newly available substratum of the wooden poles. |
In some of the groyne fields the bank fixation was (partially) removed so that more knowledge of the effect of the shielding could be retrieved from monitoring efforts. | In some of the groyne fields the bank fixation was (partially) removed so that more knowledge of the effect of the shielding could be retrieved from monitoring efforts. | ||
Revision as of 11:14, 7 June 2010
Lek bij Everdingen - Groyne shields
Key features of the case study
Site description
The Lek river is one of the major Rhine tributaries in the Netherlands. The river is channelised and groynes are present to keep the river suitable for navigation purposes. Also, banks are fixated to avoid sediment input into the main channel. The specific site of this project is situated near the town of Everdingen. The area is characterized by continual passing of ships and barges. This causes disturbance of the water flow which in turn is thought to disturb the biota in the groyne areas.
Measures selection
To avert the disturbance in the water flow caused by passing ships a number of groynes were shielded off by artificial structures placed in front of the groynes. These structures were made of two rows of wooden poles with branches in between them. The reasoning behind this measure was that the coils in the water would be stopped by these poles and a more suitable habitat, primarily for macrophytes, would be established in the groyne fields. The presence of macrophytes would in turn increase habitat availability for fish and benthic invertebrates. Benthic invertebrates were thought to also be able to benefit from the newly available substratum of the wooden poles. In some of the groyne fields the bank fixation was (partially) removed so that more knowledge of the effect of the shielding could be retrieved from monitoring efforts.
Success criteria
The goal of the project was to stimulate the development of shore and waterplant vegetation. This may also positively affect the other WFD BQEs, namely benthic invertebrates and fish. No definitive values were determined for the success or failure of the project or the respective BQEs at the start of the project. The BQEs were all monitored and evaluated by experts in their respective fields.
Ecological response
Hydromorphological response
Monitoring before and after implementation of the project
Socio-economic aspects
Contact person within the organization
Extra background information
References
