Charterhouse Restoration Works

Overview

In March 2025, we will be carrying out restoration works in Charterhouse Heritage Park with approved contractors. The project aims to re-naturalise the River Sherbourne which flows through Coventry, improving it for nature and for local communities. There will be several elements to this particular restoration project, all of which will have a positive effect on the river and surrounding area both now and for the future.

The work is estimated to take 2-3 weeks to complete, and will include improvements to the river channel itself, as well as the installation of an "on-line" pond feature which will connect to the river. Access to the side of the river next to the car park may be limited during some periods of the restoration work, but will be still available on the other side of the river and full access will remain once the project is completed, with the river being more visible and accessible to people and wildlife.

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Community Consultation

It's important to note that this restoration project has been discussed and positively approved by the public at several consultation days. Some of these were in the development phase of the project in June 2021, where we spoke to the public over 3 separate events. We also discussed the proposed works at a consultation day in October 2024.

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Why are we doing the River Restoration?

Since 2021, we have been monitoring the river, including a full site walk over. We concluded that the river is artificially too wide and too deep, due to alteration over time. These cause issues for wildlife, the river does not create natural features which wildlife can use. The flow speed of the river here is also too slow, which causes lack of diversity and can cause over-sedimentation. We are looking to create artificial features to provide this diversity in habitat and flow speeds that wildlife requires. This will enable a more natural river over time and increase the habitats for wildlife.

The existing river substrates are mostly comprised of brick and rubble, which is not as beneficial for wildlife as natural river pebbles. Riverfly and trout require these rounded pebbles for breeding. The rounded pebbles will also be far better for oxygenating the water. The banks are also too steep, making the river less visible and accessible. Through the bank reprofiling, we will make this more appealing and accessible for people and wildlife.

There is a lot of potential in creating a pond feature which provides more habitat for wildlife, particularly as a refuge for fish fry. Charterhouse is a brilliant area for nature connection in Coventry ,and provides a space for interaction, engagement and education about our rivers and wetlands. By adding a pond which has a path, we are helping to support this narrative and encourage nature connection.

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What will we be doing?

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Pond Feature

We will create an ‘on – line’ pond feature using plant machinery. This means that it will be attached to the main river via a channel. The feature is being created south of the play area and just past the benches, where there is remnant wetland plant species, indicating that it is a perfect site for a pond.

Positives:

• Due to the pond being attached to the main river, it will make a great refuge for fish fry (young fish), further increasing the viability of fish breeding.
• The pond feature will create a great habitat for other wetland wildlife, such as invertebrate species and wetland plants.
• The pond feature will result in a slightly increased water storage capacity, giving storm water an area to be stored after storms, which slightly improves the natural flood management of the area.

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"Cut & Fill" Berm Features

We will be using 3 "cut and fill" berms to help to narrow the river channel. The term "cut and fill" refers to the approach of regrading the banks (cut) and using the earth moved to form (fill) the berm feature. The 3 "cut and fill" berm features will all be on the south bank of the river.

Positives:

• By narrowing the channel, these berms encourage faster flow, reducing silt build-up and keeping the water cleaner.
• The meandering effect creates varied flow speeds, supporting a greater range of aquatic and bankside species.
• Regrading the banks makes the river more visible and accessible for both people and wildlife, enhancing engagement with nature.

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Brash Berm Features

We will be adding 6 brash berm features in an alternate pattern to the "cut and fill" berms to encourage a natural meandering pattern, which will also support in narrowing the river channel.

Positives:

• These structures use woody material to stabilise the riverbanks, reducing erosion and protecting against flooding.
• The brash provides shelter for fish, amphibians, and invertebrates, increasing biodiversity.
• By narrowing the channel, these berms also encourage faster flow, reducing silt build-up and keeping the water cleaner. The meandering effect achieved by the alternate placement creates varied flow speeds and promotes diverse habitats in the river.

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Gravel Recharge Features

We will be placing 6 gravel recharges in the river at select locations, to add properly sized gravels to the channel, which are better and more natural than the existing less rounded rubble gravel that is currently there.

Positives:

• Adding appropriately sized gravel provides ideal conditions for fish like Brown Trout to lay their eggs, and also many invertebrate species.
• Water flowing through the gravel increases oxygen levels, benefiting aquatic life.
• Restoring the riverbed with fresh gravel supports natural sediment movement and helps the river function more effectively, kickstarting natural processes.

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Additional Features

After the March restoration phase, we will also look to return to Charterhouse Heritage Park to construct a path around the pond for access. In the future we will also be looking to put a pond dipping platform and possibly a bench in to support the use of the pond feature as a place for engaging with nature.

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What are we doing with the soil?

As indicated by the map above, the soil (sometimes referred to as spoil) from the pond feature will be kept on-site, and placed on the slope below the playing field. As we finish the work, the contractors will be smoothing over the soil area and any tracks created by the plant machinery, and reseeding the area with an amenity grassland mix.

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Methods & Working Avenues

We have gone through all the correct avenues to secure permission from the council (who are an active partner in the project) and get a bespoke flood risk permit from the Environment Agency (who review it from a flood risk, biodiversity and fisheries perspective). We will have agreed Environmental Mitigation Measures with the council ecology team, covering protection for various wildlife, considering disturbance and biosecurity controls. They are happy that we are carrying out adequate environmental protection measures for the works which include:

• Silt control - silt mat and curtain downstream of works to capture any silt disturbed during the works and appropriate removal off site once finished.
• Only taking out the necessary trees/tree limbs to allow access for plant machinery if required, after doing the necessary checks for bird nests and any bat roosting potential.
• We will have a watching brief from the EA or a sufficiently qualified ecologist to ensure there is no fish or bird nest disturbance.
• We will have ecological appraisal from a properly qualified ecologist prior to works taking place.
• Removing Himalayan balsam from the site before works take place to ensure we don’t spread INNS and ensuring all correct biosecurity measures are in place with the contractor during the movement of machinery and works.

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