Background

Flooding has become a recurring and increasingly disruptive issue for residents in Cossington, Leicestershire, with some properties experiencing prolonged displacement following severe flood events. Changing weather patterns and revised Environment Agency guidance, which now considers 1 in 30 year flood events rather than the traditional 1 in 100 year benchmark, have heightened the urgency for effective flood mitigation.

In response, Severn Trent Water commissioned a dedicated flood alleviation scheme to protect homes and infrastructure from future stormwater flooding, delivered by contractor NMCN.

The challenge

The scheme needed to deliver rapid and reliable flood protection while responding to several wider pressures:

  • Increased flood frequency impacting residential communities
  • Limited budgets and growing demand on emergency services
  • A requirement for fast track installation
  • The need for robust attenuation capacity within a floodplain location
  • Minimising disruption, vehicle movements and environmental impact during construction

A solution was required that could be delivered efficiently, provide long term resilience, and adapt to site specific hydraulic needs.

The solution

Marshalls supplied a bespoke off site manufactured water management system, combining 900mm precast concrete pipes for floodwater storage with precast tank systems for attenuation control.

The tank systems were custom designed to suit the specific requirements of the Cossington scheme, making them suitable for use where conventional circular chambers were not appropriate. Manufactured off site and delivered ready for installation, the tanks did not require a concrete surround, delivering multiple benefits:

  • Reduced installation time
  • Fewer lorry movements to and from site
  • Lower material use and on site waste
  • Improved safety by minimising confined space working

Where required, the systems were configured to accommodate flow control devices, including weir walls, Hydro Brakes®, orifice plates and penstocks, ensuring stormwater was released in a controlled manner to protect both residential and commercial properties.

Marshalls also provided a full design package, including calculations and drawings, with all systems manufactured in accordance with relevant British Standards and Eurocodes.

The outcome

The bespoke precast solution delivered a safer, faster and more efficient flood alleviation system for the village of Cossington.

  • Significant reduction in on site wet trades and confined space working
  • Faster installation and improved site safety
  • Reduced vehicle movements and environmental impact
  • Long term reduction in maintenance requirements
  • Bespoke attenuation strategy tailored to local flood risk

John Wright from NMCN commented:

“The products manufactured by Marshalls have been of high quality and fast to install, which is great for our on site people, as wet trades are closed quicker and vehicle movements are kept to a minimum.”

Billy Fairhurst, Specifications Manager at Marshalls, added:

“All of our watertight systems are bespoke. With modular formwork, we have the flexibility to create innovative, project specific solutions with minimal in situ works.”

The scheme demonstrates the value of bespoke, off site precast water management systems in protecting vulnerable communities from increasingly frequent flood events.