Case Study | Water Vole Surveys and Mitigation in Norfolk

In summer 2024, Connected Ecology carried out water vole surveys in Norfolk, near Abbots Hall, to determine whether water voles were present at a site proposed for river and ditch improvements.

The works were being planned by the National Trust to enhance habitats for European eel, with funding from Natural England. As water voles are a protected species, ecological surveys were required before any works could begin.

Water Vole Protection

Water vole are fully protected under the Wildlife and Country Act 1981. This species is protected from injury, killing and disturbance whilst in a place of shelter. In the last 30 years, there has been a dramatic population decline due to habitat fragmentation, land management changes and invasive species.

Water Vole Survey Results

During a single survey visit, we confirmed that water voles were present on site. We also identified suitable adjacent habitat that could support water voles if they needed to be temporarily displaced during the works.

This early confirmation helped keep the project moving efficiently while ensuring full compliance with wildlife legislation.

Mitigation Strategy and Protected Species Licence

Following the survey, Connected Ecology produced a detailed Water Vole Mitigation Strategy and Method Statement. This document supported an application for a water vole protected species mitigation licence, which was successfully determined and issued in autumn 2024.

Due to circumstances beyond our control, displacement works did not take place in autumn as planned and were instead carried out in spring 2025.

Water Vole Displacement Works

The displacement was carried out carefully and successfully using a combination of methods, including:

• Vegetation clearance using strimmers, as well as by flail and Bradshaw attachments on an excavator

• Raking cut vegetation to achieve bare earth

• Removing droppings and other signs of water vole activity

At this stage, only burrows remained.

Approximately one week later, we returned to check for any signs of water vole activity and confirmed that none were present. An excavator with a ditching bucket was then used to lower the banks, and burrows were carefully dug out by hand.

Habitat Creation for Water Vole and European Eel

Once displacement was complete, we worked closely with the Water Management Alliance (WMA) Internal Drainage Board (IDB) to deliver shallow bank profiles suitable for European eel.

The adjacent banks of the watercourse were then built up and shaped to create high-quality habitat for water vole, resulting in:

• Improved water vole habitat

• Enhanced eel-friendly watercourses

• Better outcomes for wildlife overall

Woody Debris

As part of the proposed Scheme, several woody debris were also installed within the river as part of habitat improvement. Woody debris can be achieved by either felling a tree and pinning it or staking it to near the bank side of the river, or by partly cutting the base of a tree and letting it naturally fall and then positioning it against the bank. Although we confirmed water vole presence on most of the river, we were able to find places with no water vole burrows, thus avoiding the need to do water displacement, and still achieve the objective of installing woody debris in the river. This meant that works could go ahead with less time constraints as they were not limited to either spring or autumn displacement window.

This project delivered a net gain for biodiversity, with long-term benefits for multiple species.

Watch the Project in Action

Check out our video showcasing the key stages of the works and the finished habitat creation.

What’s Next?

We look forward to completing post-construction monitoring surveys in 2026 to see how the habitats have re-established and how wildlife responds to the improvements. Watch this space!

Want help with a water vole survey? Get in touch with our ecology team today