Case Study
Yearl Weir bank protection
Construction, Infrastructure & DevelopmentClient
Salix River & Wetland
Location
River Derwent, Cumbria
Objective
River restoration works
Challenge
Addressing water quality risks during works; low oxygen and silt pollution
The challenge
Recent flood events accelerated bank erosion on a reach of the River Derwent, east of Workington, Cumbria compromising an access road to the Yearl pumping station and threatening the structural stability of the Yearl weir.
The River Derwent is an important habitat for various fish species including Atlantic Salmon, Lamprey, Sea Trout and Brown Trout as well as an important drinking water supply.
Salix were enlisted as the appointed contractor to reinstate the 160m length of bank in this ecologically sensitive site. They identified that strong environmental protection would be required throughout the duration of the project including silt control.
The solution
We worked alongside the team at Salix to advise on the method of work to minimise silt and find a low-cost silt control solution that did not use chemical treatments.
It was decided to surround the work areas with Silt Wattles, untreated Floc Mat® and Silt Mats™ which, in combination, created a pool where flow could be limited to enhance the settlement of silts and provide a natural fibre filter, restricting the suspended solid load entering the main river flow.
In addition to this a further silt barrier was installed in the form of a bubble curtain, this is made up of two lines of ¾” diameter Bubble Tubing®. An air compressor located on the bank pushes air through tiny holes in the Bubble Tubing® to create a wall of bubbles.
The bubbles create a flow pattern that hold the sediment back, whilst the centre of the bubble curtain baffles and augments the water to prevent the transition of silts downstream.
Long-term silt capture
Floc Mat® and Silt Mat™ were used for long-term silt capture without frequent replacement. Water attenuation ponds were also employed to slow water flow and capture heavier silt particles.
Innovative water treatment
The innovative solutions ensured effective silt pollution prevention and sediment control. Gel Flocculant, Floc Mat® and Silt Mat™ used in conjunction with the Pipe Reactor, provided an environmentally safe and efficient method to treat clay-impacted water.
Minimal environmental impact
The Silt Capture Channel offered robust and long-lasting silt capture capabilities. Water attenuation ponds played a crucial role in managing water flow and capturing heavier silt particles, ensuring minimal environmental impact.
The results
Environment protected
Protections put into place that kept wildlife safe from silt pollution.
Cost-effective solutions
Early intervention and planning ahead saved money.
Low carbon design
Low carbon solutions which deliver immediate, effective and beneficial results.
The products
Silt & Debris Bubble Barriers
- Controls sediment plumes, preventing silt and debris spreading in water
- Protects habitats by shielding sensitive aquatic life and ecosystems
- Creates a flexible silt control barrier that is designed to adapt to varying water depths
- Quick to deploy and remove without inhibiting navigation
Silt Mat™
- Cost effective silt pollution control on site
- 100% biodegradable for easy disposal or seed onsite
- Can be used on land, in ditches, streams or rivers
- Unique heavy-weight design delivers longevity on site
Floc Mat®
- Low cost, low carbon way to treat clay-impacted water run-off
- Can be used on land and in ditches
- 100% biodegradable for easy disposal or seed onsite
- Simple to deploy and highly effective at controlling fine particle silt pollution
Silt Wattle
- Traps sediment, slows runoff and captures soil
- Flexible enough to work on slopes and uneven ground
- Quick to install, lightweight and easy to place
- Offers a cost-effective silt and erosion control option
Case Studies
Real solutions, proven results
Knowledge Hub
Sharing good practice
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13th November 202512:00 pm – 1:00 pmFree CPD webinar: Preparing your site for winter shutdown
Preparing for winter shutdown is a critical part of good site water management planning. Join our technical team for this free webinar.
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