Essex Rivers Hub

Improving in-channel habitats in the floodplain

The flood plain grassland, which is managed through horse grazing, has little to offer in terms of habitats for aquatic species. The channel is very steep banked, wide, straight, no tree cover and little bankside vegetaion.

In order to address loss of variation in the channel, resulting from dredging and straightening of the channel in the past, we propose creation of habitat within the channel. This would take the form of earth berms, which is where areas of the bank are pushed into the channel to create raised areas and also restrict the channel width at low flow. This will create areas for plants to grow, refuge areas for fish and invertebrates and also variation in flows. Where possible we will also install woody debris by staking tree limbs into the bank and securing it to the bed to prevent it from washing down stream. Again this will create in channel habitats for fish and invertbrates and also diversify flow.

By pushing in areas of the bank to create the berms this will also create better connectivity between the channel and the flood plain. At present, due to the raised areas on the bank, when the flood plain floods at high flow the water is unable to flow back into the channel once the water level drops. It is hoped that better connectivity will create a more natural flood plain/channel dynamic.

We will also be creating a 'scrape' on the south bank, which will involve creating a shallow depression in the bank by scraping away the soil. This will allow areas for water to accumulate and remain even when the water levels have dropped and create wetland areas. This will diversify the plant communities that are found in this area and create habitat for wading birds.

We will also plant more trees along the bank. This would create areas of shade within the channel which can improve oxygen levels in summer and also allow different in-channel habitats to develop. They will also be future woody debris.

Please contact us if you have any questions or suggestions regarding this project idea.

RBD/catchment/river/tributary

River Mardyke

WFD water body status

Poor

WFD overall status objective

To achieve Good ecological status by 2027

Project type

habitat creation/structural

Benefiting species and/or habitats

Creation of in-channel habitats would improve biodiversity and the creation shallow banks will give the opportunity for different plant species to develop. Planting of trees would improve oxygen levels within the river reducing the potential for fish kills when temperatures are high in the summer.

Project lead

Essex Wildlife Trust

Contact for more information

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Project partners

Essex Wildlife Trust, Essex Biodiversity Project and the Environment Agency, Thurrock Council

Funding source

Catchment Partnerhsip Action Fund

Project start

May 2015

Project end

March 2016

Website key stakeholders:

Environment Agency logo      Essex Wildlife Trust logo            Essex Biodiversity Project logo

Design by LTD Design Consultants and build by Garganey Consulting based on an original concept by Herts and Middlesex Wildlife Trust