Essex Rivers Hub

Chelmer Valley LNR Part Two

This project builds on the original project at Chelmer Valley LNR undertaken in 2015, by installing some a further berm, installing some new scrapes and putting in an additional fish refuge, at an area just north of Chelmer Valley Bridge. 

The project was undertaken in early 2017, completed the project at the Chelmer Valley Local Nature Reserve with the installation of one new berm to improve local flow velocity, installing four new scrapes and an additional fish refuge. The aim of the project was to improve the overall riparian habitat quality but also it will help to store and attenuate flood water. 

The first intervention was to reprofile the bankside and create a new berm feature. This area of the river is characterised by slow, sluggish flows which means silt can drop out of the water, smothering gravels and allowing choking weeds to develop. Therefore to introduce some faster flowing water and expose these gravels would enable the river to manage itself, introducing gravel and a column of oxygenated water and benefit the wildlife found in this reach and wider afield. 

Before: Sluggish, slow flow typical of this stretch of river

After: Berm introduced and bankside reprofiled

The difference between before and after is remarkable. Visually in this picture, you can see the turbulent water typical of faster-flowing columns of water indicating that this is already having an effect on the local flow velocities. 

Via the process of creating the berm the bankside has been lowered, this also has benefits to wildlife as it means that silt is settled outside of the river and it also increases the connectivity of the floodplain, allowing this section of river to behave in a more natural fashion and aid the creation of natural riparian habitat including wet meadows and wet woodland. 

A major part of this intervention was to create four new scrapes or ponds. Scrapes are shallow seasonally flooded areas of land which are incredibly vital and valuable to wildlife. The aim of the scrapes is to create a mosaic of wetland habitats that are flooded in the winter and stay wet into summer, for the benefit of wildlife. There also store and attenuate floodwater, especially during the summer months.

Before: Floristically uninteresting grassland at Chelmer Valley Local Nature Reserve

The scrapes are connected to the river via an existing ditch network, which should enable them to be seasonally flooded and thus benefit the wildlife of the River Chelmer. 

 

The scrapes were created using an excavator. The average depth of the scrape was the same as the existing ditches on the site. 

After: Newly created scrape at Chelmer Valley LNR

Fish refuge at Chelmer Valley Local Nature Reserve

The final intervention was the fish refuge, fish populations in the Chelmer are declining. Partly as a result of the numbr of interventions on the Chelmer which prevent natural fish movements. Fish refuges work by providing a place out of the main flow, especially during high flow events were fish, especially young fish can sit out flooding incidents and avoid being washed downstream, helping to maintain fish populations in this area. 

It is still early days for this project, but all the bare areas have been reseeded with a low maintenance meadow mix which should hopefully produce a nice varied sward. The final aim this project is to plant trees which will be the final piece of the jigsaw in creating this mosaic of wetland habitats. 

Thanks must go to Luke Bristow at Essex County Council and the Environment agency for funding this project. 

  

RBD/catchment/river/tributary

River Chelmer

WFD water body status

Poor

Project type

River Restoration

Project lead

Essex Wildlife Trust

Contact for more information

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Project partners

Environment Agency

Project start

2012

Project end

2017

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