Otter Survey and Camera Trap Monitoring for River Repair Works

The Brief

We were commissioned by AECOM to undertake an otter survey in support of proposed repair works to a collapsed river retaining wall in South Wales.

Otters (Lutra lutra) were known to be present in the wider area, and a potential holt had been identified during a previous inspection. An updated survey and monitoring programme was required to determine whether otters were actively using the site and to inform mitigation to ensure compliance with wildlife legislation.

Our Role

We delivered a focused field survey and monitoring strategy, including:

• Otter survey of approximately 0.7km of riverbank (both banks) to identify field signs and assess suitability for resting places or holts
• Deployment of two motion-activated camera traps targeting the potential holt location and the section of river where works were proposed
• Regular checking, downloading and detailed analysis of footage to determine otter activity
• Preparation of a technical report outlining methods, findings and clear mitigation recommendations

Our approach provided robust, site-specific evidence to inform decision-making and programme planning.

Outcomes

• Confirmed that otter holts were likely absent from the works area
• Provided proportionate mitigation guidance
• Enabled the client to proceed with repair works in compliance with protected species legislation
• Delivered clear, timely reporting aligned with project needs

Client Feedback

“Friendly service with a can-do attitude. Worked to meet our specific project needs. I’d be very happy to work with Thomson Environmental Consultants again.” Principal Engineer, AECOM Ltd

Practical ecological advice supporting essential infrastructure maintenance.