The first phase of the £56m Rochdale and Littleborough Flood Risk Management Scheme is underway, using our innovative ‘rain-ready’ system to handle polluted water created by construction activities.

The project works include the construction of a flood storage reservoir and sections of linear defences both upstream and downstream as well as modifications to existing defences along the river Roch.

We are providing silt control products and design advice for the project – our ‘rain-ready’ system comprises Pipe Reactor, Gel Flocculant, Silt Capture Channels and settlement ponds.

We estimate that VolkerStevin are saving in the region of £50k – £128k over 12 months by using our Rain Ready water treatment system compared with other solutions on the market. We pride ourselves in providing biodegradable, low carbon solutions that save money for our clients and protect the environment.

Our achievements at a glance:

Independently verified water testing, led by Frog Environmental, showed our rain ready water treatment system has already achieved:

• Up to 99% reduction in total suspended solids (TSS) levels. Reducing from 346 mg/l TSS to 2 mg/l TSS during July monitoring.
• Our systems met the conditions set by the regulator under the terms of the Environmental Permit (Discharge Consent) for Total Suspended Solids (TSS) and pH.

Many heavy metals were reduced as a result of the treatment including Aluminium, Arsenic, Barium. Cadmium, Chromium, Copper, Iron, Lead, Manganese, Nickel, Phosphorus and Zinc. This is reflected in the Chemical Oxygen Demand reducing by 77%, protecting the dissolved oxygen levels of the receiving watercourse and subsequently, the fishery.

• 83% reduction in total Phosphorus, reducing the impact of eutrophication in the wider catchment.
• 99% reduction in total Aluminium (meaning the water being discharged is in line with drinking water standards).
• 98% reduction in Lead
• 91% reduction in Manganese (bringing the discharge to meet drinking water standards)
• Up to 98% reduction in filtered Iron (this means that water quality wise it was within drinking water thresholds).
• 99% reduction in total Iron, meeting Water Framework Directive proposed quality standards.
• 91% reduction in Zinc.
• 85% reduction in Arsenic.

“With increasing UK rainfall over recent years, and anticipating potential delays, the site was designed with a rain-ready mitigation system to tackle the inevitable surface water.”

VolkerStevin explained that the design reduces the need for continual pumping with water left in the settlement pond as required. Pre-construction testing showed the soil particles are small and take over 24 hours to settle, which means the water could not be discharged without significant mitigation.

“Water is pumped through a Pipe Reactor where it is treated with Gel Flocculant to reduce settlement time, then into settlement ponds and a final polishing pond, which runs over a series of biodegradable mats to remove any remaining silt.”

Richard Walsh, Senior Project Manager at VolkerStein

“The rain-ready approach of using Silt Mats™, settlement ponds and Silt Capture Channels means the equipment remains in place year-round, ready for use whenever needed. Independent laboratory testing has shown that there is 99% reduction in total suspended solids and up to 99% reduction in iron. This means the water being discharged back into the river actually meets the threshold for drinking water standards.

“VolkerStevin contacted us early on in the process, giving plenty of time for discussion and review before the project’s critical works began. It really emphasises what can be achieved with early engagement towards water management.”

Gavin Beat, Senior Technical Specialist at Frog Environmental

Collaborative working achieves environmental standards

VolkerStevin engaged with us early in the project to discuss options to implement a process for cost effective, environmentally friendly water treatment. Involving us early is extremely important and allowed detailed discussions to take place and a solution designed prior to the start of critical works requiring water management.

We carried out settlement testing, often used as part of our process in designing the best solution for a site, from water and soil samples provided by VolkerStevin.

Within a month of our first call, settlement testing was carried out, a site-specific system was designed and our products were delivered to site. With our guidance, VolkerStevin self installed the Silt Capture Channel.

Our technical team provide a mixture of remote and on-site support, with the majority carried out remotely communicating closely with VolkerStevin’s capable site teams.

Award-winning site

This approach to water management is one of several sustainability-focused approaches taken on-site for this phase of works. Other approaches included the use of low-carbon sheet piling, biofuel usage, reuse of crushed concrete for the haul road, and hybrid vehicles.

The project won the Green Apple Award 2024 in the Building and Construction Flood Protection category – National Champion.

Project partners and scheme objectives

The Rochdale and Littleborough Flood Risk Management Scheme is being led by the Environment Agency in partnership with Rochdale Brough Council, and has been supported by Network Rail, the North West Regional Flood and Coastal Committee, Transport for Greater Manchester, and the Departments for Education and Transport.

Once complete, the flood scheme will better protect 723 homes and 489 businesses from flooding. The Littleborough section will better protect 337 homes and 185 non-residential properties. Additionally, the scheme aims to provide considerable environmental benefits, with 1.2 acres of woodland enhancement at Grove Lodge and over 130 trees and 160m of hedging to be planted.

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For further information on how we can help you with your site, please feel free to get in touch.     

As leaders in silt control, we offer a non-obligatory call or Teams meeting with our technical team to talk through your needs at any stage of your project and see where we or our environmentally-friendly product solutions and technical expertise may help. 

Frog Environmental are water quality & silt control specialists working with contractors, regulators and consultants within construction, utilities, marine and coastal and public sector industries across the UK and Europe.

We bring innovation to the market through a range of cutting-edge products backed with our technical team’s knowledge, and strive to create new benchmarks for environmental protection, client efficiency and value.

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