Emergency Nature-Based Riverbank Stabilisation

Executive Summary

Carmarthenshire County Council asked Enviroculture to assess and stabilise a collapsing section of riverbank beside a woodland footpath at Pontyberem Rugby Pitch. The bank was eroding, the edge of the path was falling away, and urgent action was needed to protect public access while avoiding unnecessary disturbance to the river corridor.

Enviroculture delivered a sensitive, nature-based erosion control solution using coir rolls, hazel faggots, live willow, locally harvested willow, chestnut support and native wetland planting. Following storm conditions, the site was monitored and a rock mattress was installed behind the structure to prevent further erosion and provide additional localised stability.

The works were approved by NRW following Enviroculture’s proposal and report. Delivery was undertaken in low river levels, outside the ecological embargo period, with operatives in full PPE and lifejackets, and without machinery entering the river corridor.

About the Client

Carmarthenshire County Council manages public assets, access routes, green spaces, footpaths and environmental infrastructure across the county. At Pontyberem Rugby Pitch, the Council required a practical and environmentally sensitive solution to protect a failing section of riverbank next to a woodland footpath.

The Council was keen to trial a nature-based method that could stabilise the bank while remaining sympathetic to the woodland and river setting. The project also provided a useful pilot for similar erosion protection schemes on future sites.

The Challenge

A short but vulnerable section of riverbank had begun to collapse, with the adjacent footpath falling towards the river. Although the affected area was approximately 3 metres long, the risk was significant because further erosion could undermine public access, increase safety concerns and allow more material to wash into the watercourse during high-flow events.

The works had to be planned around a sensitive live river environment, changing river levels, limited access and nearby woodland vegetation. The solution needed to provide immediate support while encouraging longer-term natural stabilisation.

·    The footpath was too close to the failing bank and needed to be moved away before stabilisation works began.

·    The works required NRW approval before commencement, based on Enviroculture’s proposal and report.

·    The river corridor had to be protected from silt disturbance, so no machinery was used within the watercourse.

·    Operatives worked close to water and therefore wore full PPE, including lifejackets.

·    The works were programmed during low river levels and outside the ecological embargo period.

·    Storm conditions after the initial installation tested the works and required follow-up monitoring and remedial strengthening.

The Solution

Enviroculture proposed a nature-based erosion protection system to stabilise the bank, reduce scour and support long-term vegetation establishment. The approach used natural materials wherever practical, with a discreet structural element added during follow-up works where monitoring showed that additional stability was needed.

Coir rolls were installed along the lower bank to provide immediate erosion protection at the toe of the bank. Hazel faggots were used to help slow the flow, trap sediment and support the bank structure. Live willow was driven and woven into the bank to create a living revetment that can root and strengthen over time.

Some willow was brought in for the works and additional willow was harvested locally on site. Chestnut was used to hold the system while the willow and marginal planting establish. Once storms had passed and river levels returned to normal, native wetland and marginal planting was added, using suitable species such as sedges, rushes, yellow flag iris, water mint and purple loosestrife.

Implementation

Phase 1: Footpath realignment

Before bank stabilisation began, the footpath was moved away from the eroding edge. This reduced pressure on the failing bank, improved public safety and created a safer working area for the team.

Phase 2: Nature-based bank protection

The team installed the coir rolls, hazel faggots, live willow and chestnut support by hand, with no machinery entering the river corridor. Works were completed during low river conditions and outside the ecological embargo period to minimise environmental risk.

Phase 3: Monitoring and remedial strengthening

After storm conditions and high river levels, Enviroculture returned to inspect the performance of the works. Some willow had been affected by high flows, so it was reinstated. The team then installed a rock mattress behind the structure to prevent further erosion of the falling bank and provide additional stability while the natural system establishes.

Additional Challenges and Adjustments

The main challenge was delivering emergency works in a live river environment without defaulting to a visually intrusive hard-engineered structure. The project required a careful balance between natural materials, public safety, environmental compliance and long-term resilience.

The storm event after the first installation became an important test of the system. Instead of treating the works as a one-off installation, Enviroculture monitored the site, reviewed where the structure had been affected and made targeted improvements. This adaptive approach allowed the natural system to be strengthened without losing the character of the original solution.

The addition of the rock mattress behind the structure provided immediate reinforcement where the bank was still vulnerable. This created a hybrid solution: natural erosion protection as the primary approach, with localised stone reinforcement where site conditions showed it was needed.

The Results

·    Approximately 3 metres of failing riverbank were stabilised beside the woodland footpath.

·    The footpath was moved away from the collapsing edge before bank protection works began.

·    The works used a nature-based system of coir rolls, hazel faggots, live willow, locally harvested willow, chestnut support and native wetland planting.

·    The proposal and report were approved by NRW before works proceeded.

·    The works were delivered in low river conditions, outside the ecological embargo period.

·    No machinery entered the river corridor, reducing the risk of silt disturbance.

·    All operatives worked in full PPE, including lifejackets.

·    The site was monitored after storm conditions and strengthened with a rock mattress behind the structure.

·    The project provided Carmarthenshire County Council with a practical trial of natural riverbank erosion protection that may inform future schemes.

Lessons Learned

This project reinforced the importance of monitoring nature-based erosion protection after installation. Living systems become stronger as vegetation establishes, but early inspection after high-flow events is essential.

The storm event provided valuable evidence of where additional reinforcement was required. By returning to site, repairing the willow and installing a rock mattress behind the structure, Enviroculture improved resilience while retaining the environmental benefits of the original natural solution.

The project also demonstrated that even small sections of erosion can pose significant risk where public access is involved. Moving the footpath first and then stabilising the bank gave the Council both an immediate safety response and a longer-term erosion control solution.