Innovative silt capture system used for water run-off at major flood storage reservoir scheme

Construction, Infrastructure & Development

Case Study

Innovative silt capture system used for water run-off at major flood storage reservoir scheme

Construction, Infrastructure & Development

Client

Jackson Civil Engineering

Location

Lowdham, Nottinghamshire

Objective

Construction of £30m flood storage reservoir

Challenge

Pollution risks to nearby brook during major groundworks

The challenge

We’re supporting Jackson Civil Engineering with silt management and water treatment solutions while they build a major flood storage reservoir near the village of Lowdham, which has suffered repeated flooding.

Being constructed on behalf of the Environment Agency, once the £30 million project is complete the reservoir will store up to 10,000 cubic metres of water. This will slow the flow of storm water back into the Cocker Beck brook, and protect 191 properties and businesses from the risk of flooding.

The scheme involves significant earthworks to prepare the site for the build phase. The embankments for the reservoir are being constructed from clay excavated from the site and the course of the brook located within the site is being realigned.

There is a lot of earthmoving at various stages which creates a risk of high levels of silty water run off into the watercourse during wet weather, hindering flows and endangering aquatic life.

The project requires a solution that can:

Clean silty water
Operate reliably and with minimal maintenance
Reduce costs, carbon and pollution risks
Use sustainable materials. One of the contractor’s overall project aims is to provide a biodiversity net gain of at least 20%.

This site received a National Gold Award for Environmental Excellence at the 2025 Green Apple Environmental Awards, recognising its innovative water treatment techniques that utilise sustainable materials and carbon-saving passive systems.

The solution

Innovative silt capture system that is sustainable, easy to use and reliable

Our cost-effective Rain Ready® silt control and water treatment system comprising Clearflow Gel Flocculant and Silt Capture Channel has been installed on site and is helping to clean water before discharge.

Controlling silt pollution risks on site is important for meeting environmental regulations and protecting aquatic species from harm in the brook that transects the site.

Water samples were collected in late 2023 and our advice was given on proposed silt control measures for the site based on our settlement test findings and existing site infrastructure.

Jackson Civil Engineering first installed the channel as part of the passive site drainage system in 2024. The passive treatment systems have been designed in conjunction with our technical team and involve several points where water is intercepted by drainage channels or collected in attenuation ponds where it is treated with Gel Flocculant before moving across our Silt Capture Channels which collect silt from the treatment point and polishes the water, and finally leaves the treatment area.

We’ve applied a dynamic treatment approach to this site as the site landscape continues to evolve. The system was initially set up passively to capture the runoff from a huge area of exposed soils. More recently, it has been used to support dewatering the site’s attenuation pond prior to winter shutdown, treating pumped water through the silt capture system to give the site additional capacity.

Our technical team has provided advice at various stages of the ongoing project, particularly during installation and maintenance of the system. A benefit of the silt capture and water treatment system is that it is made up of components which can be refurbished easily at the end of their life, and being 100% biodegradable, can be repurposed to create biodiversity enhancement.

Versatile solution

Depending on the available space, topography and pumping rate, our Rain Ready® water treatment system can be formed in different configurations to suit the constraints of a construction site.

Zero carbon approach to treating water

For this scheme the system is designed without pumps, enabling zero-carbon operation for treating water, negating energy and other operational costs.

Environmentally-friendly products

Our water treatment system is good for the environment through the use of biodegradable materials.

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Green Apple Award for silt capture at Lowdham

Installation of Silt Capture Channel at Lowdham

Water leaving Frog treatment point at Lowdham

The results

Effective silt capture

Each mat within the Silt Capture Channel is collecting up to 40 – 50kg of silt.

Dirty water turns clear

Our Rain Ready® water treatment system comprising Gel Flocculant and Silt Capture Channel is treating up to 900 litres of dirty water per minute.

Zero-carbon approach to silt capture and water treatment

A gravity-fed system has been applied to this site, saving on pump hire and fuel costs, and reducing carbon emissions.

Award-winning approach to silt control

Early planning and proactive management to silt control using our biodegradable and low carbon solutions has won a national gold award for environmental excellence.

Our products

Gel Flocculant for Silt Control

Can be deployed passively in flowing water or in pumped systems (Pipe Reactor & Clearflow GFR)
Long lasting, low maintenance silt control devices
Supplied with site review service to ensure correct site-specific deployment and efficacy
The most cost effective method to manage fine suspended solids on site

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Silt Capture Channel

Captures silt and flocculated fine silt particles
Unique design utilising Frog Environmental products
Standard design polishes up to 900 litres per minute
Supplied with site review service to ensure correct placement on site

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We’ve been impressed with the innovative Silt Capture Channel and Gel Flocculant system for its performance, ease of use and how it is helping us to meet environmental and sustainability objectives at Lowdham. We’ll be encouraging teams to consider this solution on other suitable projects across our network.