Worthyvale Weirs, England

Introduction

The Upper River Camel, situated in Cornwall, England, is a stunning and culturally significant project area. Originating in Bodmin Moor, the river spans about 30 miles, winding through picturesque villages, fertile valleys, and diverse landscapes before meeting the estuary near Padstow. This region is ecologically vital, boasting various habitats that support diverse flora and fauna, including otters, Atlantic salmon, and various bird species. Designated as a Site of Special Scientific Interest (SSSI) and Special Area of Conservation (SAC), conservation efforts are critical to protect its biodiversity. The area also holds historical and cultural significance with ancient settlements and structures scattered throughout the landscape. Balancing ecological preservation and human activities, including sustainable land management and responsible tourism, presents ongoing challenges. Overall, the Upper River Camel is a captivating blend of natural beauty, heritage, and ecological importance, inviting exploration and appreciation.

Project context and opportunity

The River Camel in Cornwall faces a unique project challenge: managing or potentially removing historical weirs that have altered its natural flow. These weirs, originally built for mills and drainage, have disrupted habitats and impeded fish migration, particularly for salmon and trout. Addressing them will restore the river’s dynamics, enhance biodiversity, and make ecosystems more resilient. Removing the weirs improved habitat connectivity, benefitted sediment flow, nutrient exchange, and aquatic organism movement, and reduced flood risks downstream. Balancing historical significance with ecological restoration can foster community engagement. Moreover, restoring natural flow patterns can boost the river’s adaptability in the face of climate change.

Project aims

The primary project goal of weir removal in the River Camel area is to restore the ecosystem’s natural ecological integrity and hydrological balance, fostering a cascade of positive impacts that benefit both the environment and the communities that depend on the river. This restoration promotes fish migration and improves water quality, increasing biodiversity and healthier aquatic populations.

With weirs out of the equation, the river is more accessible for fish, particularly species like salmon and trout, which rely on unobstructed routes for spawning and migration. The project aims to improve fish habitats and contribute to the recovery of dwindling fish populations, benefitting recreational fishing and the aquatic food web.

The revitalised river ecosystem becomes a more attractive destination for outdoor enthusiasts and tourists. Improved opportunities for angling, kayaking, and nature appreciation can stimulate local economies while fostering a deeper connection between people and the river.

Project achievements

The project, which began on 1st December 2022 and concluded on 30th November 2023, achieved significant milestones as outlined below:

Stakeholder Engagement and Permissions:

• Liaison with governing bodies, including Natural England, the Environment Agency, and Cornwall Council, was successfully undertaken to obtain the necessary permissions for the proposed works in a Site of Special Scientific Interest (SSSI) and Special Area of Conservation (SAC).
• Permissions were granted by each party, including Land Drainage Consent (LDC) from Cornwall Council and SSSI consent from Natural England, facilitated by a comprehensive project proposal and method statements addressing potential impacts and mitigation measures.

Pre-Works Electrofishing Monitoring:

• Conducted to establish a baseline for various fish species across all life stages, this monitoring was initially delayed due to adverse weather but was completed on 24th August 2023.
• The survey revealed populations of brown trout and European bullhead, with the data indicating a fair (C) classification for trout fry and a good (B) classification for trout parr.

Barrier Demolition and Material Removal:

• The demolition took place on 31st August 2023, finishing ahead of the planned ten-day timeframe.
• The removal was efficiently executed using a 13-ton excavator, with machinery operating on biofuels and bio-oils to minimise environmental impact.

Erosion Control and Habitat Restoration:

• Eco silt screens were installed downstream to control sediment during barrier removal, and biodegradable coir erosion control blankets were used to stabilize freshly excavated banks.
• Minimal impact was observed during the removal, and immediate restoration of the upstream habitat was achieved, transforming deeper glide sections into shallow, well-oxygenated fry habitats.

Restoration of Natural Sediment Transfer: The removal of barriers reestablished natural sediment transfer, enhancing habitat conditions and making the river reach passable for all species without artificial delays.

Collaborative Efforts:

• A working group comprising local professionals was formed, and multiple surveys and meetings with key stakeholders were conducted to ensure broad support and smooth project execution.
• Key meetings included discussions with the Director of the Abruzzo, Lazio, and Molise National Park, the mayor of Bisegna, and municipal technical offices, leading to positive feedback and project endorsements.

Overall, the project’s achievements reflect successful stakeholder collaboration, effective planning and execution of ecological surveys, and efficient removal of barriers, resulting in improved river function and enhanced biodiversity in the catchment area.