River Towy, Bank Erosion, Carmarthen - Salix Solutions

Aqua Rock Bags were installed at the eroded toe of the failing riverbank after it had eroded the bank and caused the footpath to collapse into the River Towy in the centre of Carmarthen.

Brushwood being applied to the surface of the newly formed slope

A temporary jetty was installed in order to be able to load the multicat boat as no heavy machinery could approach on land

90 metres of bank erosion had eroded the bank and caused the footpath to collapse into the River Towy in the centre of Carmarthen

Natural sediment accretion and vegetation colonisation after five months

Sediment accreting around aquarockbags and brushwood fascines two years on

River Towy two years on from the air

Brushwood being applied

Temporary jetty

Bank erosion

Natural sediment accretion and vegetation colonisation after five months

Two years on sediment accreting around Aqua Rock Bags

River Towy two years on from the air

90 metres of bank erosion had eroded the bank and caused the footpath to collapse into the River Towy in the centre of Carmarthen

cbec eco engineering undertook a range of surveys to allow detailed hydraulic modelling to inform the best design solutions.

2D hydraulic model of the eroding bank and adjacent river reaches was undertaken.

The design was based upon the know shear stress at a 1;200 year flood event. An Aquarock bag toe ensured that a robust but flexible toe revetment would protect further bank scour.

A temporary jetty was installed in order to be able to load the multicat boat.

No access for heavy plant above the eroded slope was possible due to the instability of the existing erosion bank.

Aqua Rock Bags were installed at the eroded toe of the failing riverbank. Easy to install and a robust defence against erosion, these innovative solutions provide habitat for a wide range of invertebrates and allow for natural revegetation.

An Aquarock bag toe ensured that a robust but flexible toe revetment would protect further bank scour — Aquarock bag toe

Aqua Rock Bags being installed at the eroded toe of the failing riverbank

Aqua Rock Bags being installed at the eroded toe of the failing riverbank

Brushwood was applied to the surface of the newly formed slope.

The brushwood traps fine sediment and vegetates naturally to quickly stabilise the surface of the new slope.

2D hydraulic model

Products Used

AquaRockBags

Ecological AquaRockBags are tough revetments that can be used to protect assets in rivers, deep water and intertidal projects.

Details

Location: Carmarthen
High Energy Rivers, Rivers & Water Courses, Salt Marshes & Intertidal Rivers

Excellent overall performance – very approachable and offered a good sustainable solutions to rectify a significant erosion scour to the river foreshore without comprising the existing flood defence. Carried out work to agreed timescale and budget. Certainly would value their future input.

Environment Agency, Leeds

We invited Salix to re-landscape the watercourse through a design and build project. The works to the watercourse were completed within two weeks of starting on site and, despite a number of prolonged heavy rain events both during and after the works, the pre-established coir rolls and pallets all began putting on new growth within a matter of days providing the watercourse with instant channel vegetation and protection to the toe of the banks. The VMax reinforcement used to stabilise the slopes has also prevented any erosion to the sandy soil beneath and has allowed the rapid establishment of grass which wouldn’t have otherwise been possible.

South Ribble Council

We have worked with Salix on a number of projects throughout East Anglia over the last 6 years, and we have always found them to be highly professional and competent. We have used their services as suppliers of quality wetland plants, with a traceable provenance, and as contractors to both supply and plant the wetland plants. In addition we have always relied on the technical advice and knowledge of David Holland, in particular, to help answer queries from our clients regarding wetland planting schemes we have been involved in, this is an added value part of their service, for which we are grateful.

UPM Tilhill

We used HydraCX for the first time on a Network Rail project in Chipping Campden. We wanted to establish vegetation growth as quickly as possible on a slope with poor ground conditions without the need for importing topsoil due to possession time constraints. HydraCX provided an excellent growing medium for rapid germination.

Carillion Rail

Your staff are always friendly, knowledgeable and helpful and we have always been pleased with the service and the quality of the wetland plants and planting services. Technical knowledge on erosion control is also excellent. Keep up the good work!

Living Water Ecosystems Ltd

HydraCX gave an immediate impression the embankment was grassed, making it more visually pleasing to our travelling customers. The rapidity of grass growth was exceptional and it added additional strength to the slope surface.

Network Rail

Atkins has worked with Salix on a number of projects, collaborating on design concept, trialling and implementation. We have found their experience valuable in delivering cost effective and environmentally functional solutions.

Atkins