Project

Creating wetlands at Cotehele

View of wetlands area at Cotehele Quay | © National Trust Images / James Dobson

During 2021 the team at Cotehele created a new intertidal habitat at Cotehele Quay to improve the area’s resilience to the changing climate and provide a richer environment for both people and nature.

Why did we create a new wetland?

Before the wetland area was created, the field next to the Cotehele Quay car park was low grade farmland and was used for grazing cattle. The field was originally part of the main river until 1880s when an enclosing embankment was built to constrain the river and make it navigable for larger vessels. Rising river levels and the degrading bank meant that the field and Cotehele Quay were prone to uncontrolled flooding.

Working in partnership with the Environment Agency and supported by Natural England, we worked with nature to create a new intertidal habitat in a place where it was unsustainable and costly to continue repairing flood banks. Returning the farmland to the River Tamar, also provides space for a diverse array of wildlife to thrive, and protects the car park from flooding.

View of the Cotehele intertidal habitat at high tide at Cotehele Quay, Cornwall — Cotehele's intertidal habitat | © National Trust Images/Steven Haywood

What did we do?

To create the wetlands at Cotehele Quay, three trenches were dug into the ground to help bring tidal waters further into the field. A new embankment was also built to form a boundary between the car park and the wetland area.

In September 2021, a 15-metre breach was made in the bank, allowing the River Tamar to flood the farmland behind for the first time in over 140 years and to create our new intertidal habitat.

Why are wetlands important?

Wetlands are vital for resident and migratory birds, providing a safe haven for them to nest and find food. Waders can often be seen at low tide, picking invertebrates from the silt, and waiting for fish to come in as the water returns. Many migratory birds travel long distances and rely on a network of wetlands and intertidal habitats to enable them to rest and feed on their journey.

Plants, such as reeds and rushes will flourish in wetland areas, providing cover for wildlife and reducing erosion, due to their roots holding soil in place against the tide. Some of these plants rarely grow in other habitats; Triangular Club Rush, known locally as Tamar Tiger grows by Cotehele bridge and has been reintroduced in the intertidal area. Once abundant in rivers, this is now one of the only places it can be found.

Grey Heron at the wetlands at Cotehele Quay | © Stephen Crane

Fighting climate change

By creating space for the tide to ebb and flow and land to soak up and store water, this project, along with others in the Tamar Valley will work to alleviate the impact of rising sea levels and coastal squeeze which causes the loss of these wetland and tidal habitats. Wetlands are fantastic for storing and absorbing carbon and greenhouse gases; even more so than rainforests. Our Rangers regularly monitor how much carbon is being captured within this wetland at Cotehele Quay.

Wetland habitats also improve the water quality by trapping sediment and naturally filtering out pollutants. Helping to improve the health of the Tamar by cleaning the river of unwanted nutrients which are present due to industry and farming in the valley.

What’s next?

Feasibility study at Haye Marsh

Earlier this year we commissioned a feasibility study into the future management of a 17 hectare piece of land we look after at Haye Marsh.

The study looked at Haye Marsh and assessed possible options for the site, narrowing this down to a shortlist which are outlined in our feasibility report. This included an intertidal area, similar to those successfully created at Cotehele Quay and other similar projects in the Tamar Valley, continuation of the current management of the site or a mixture of the two.

These options are currently being considered by the project team. If you have any questions or comments, please email cotehele@nationaltrust.org.uk.

Read the Feasibility Study

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