An innovative flood barrier, fabricated from Duraplas® recycled plastic profiles, is now helping to protect properties in the flood-prone Stamp End area of Lincoln, as part of a £800,000 multi-agency surface water management project.
Lincolnshire County Council’s drainage team decided to use of Duraplas® recycled plastic profiles and posts from Centriforce to build the 335-metre-long, low-level flood baffle to provide an important last line of defence alongside other surface water measures for a residential tower block and surrounding social housing close to the River Witham.
In 2007 more than 110 properties were inundated and some 200 residents were evacuated from their homes for several days as a result of flooding. The County Council became a Lead Local Flood Authority in 2010 and took on the job of resolving surface water flood protection in the area.
Nathan Whitfield, Lincolnshire County Council’s Principal Drainage Engineer, explained that conventional flood barriers, such as a bund or brick wall, were ruled out because of the large number of underground utilities criss-crossing the site, some of them quite close to the surface. “The use of the plastic profiles and posts gave us the versatility to adapt the spacing of the posts, or even the route, to fit around the utilities while still getting a good 300mm depth of protective barrier underground. “Because we needed to build a barrier to fit the site, my team opted to build the baffle out of raw materials rather than specifying a pre-manufactured product. After digging a shallow trench, they used the recycled plastic profiles to build a parallel ‘rail and post’ construction, then filled the core and base with concrete.
“Our contractor found the posts and profiles very easy to handle and install. They could be easily, cut, routed and shaped to deliver the design we needed.” The flood baffle will hold back any low level surface water flooding to ensure the properties it surrounds are fully protected. Any attenuated water contained by the baffle will eventually recede into the existing local drainage systems when flows subside or, in the worst case scenario, could be pumped away.
Nathan Whitfield said he had used Centriforce recycled profiles before so was familiar with the benefits of the material. “Unlike wood, the plastic lumber will not shrink, rot, crack or lose its colour and there is no chemical leach into surrounding soil. What better product to use when you have water up against it?
“The flood wall also needed to be durable and vandal-proof with a pleasing aesthetic to blend with the street scene. A top spar, also made from Centriforce recycled plastic, provides a robust finishing touch. The project achieved cost savings because the design meant there was no need to move any underground utilities. The imaginative flood baffle has also delivered a solution with very low maintenance and minimal through-life costs, necessary to ensure adoption by Lincoln City
Council, expected in 2017.
The project’s partners were Lincolnshire County Council, Environment Agency, Anglian Water, Witham 3rd IDB, Lincoln City Council, Bifrangi UK, National Grid and Stamp End Garage
Case Study Info
Client: Lincoln City Council & Partners
Product: Duraplas® Recycled Plastic Profiles
Project: Stamp End Flood Alleviation