In 2007, over 110 properties in Lincoln were flooded and some 200 residents were evacuated from their homes as a result. Lincolnshire County Council became a Lead Local Flood Authority in 2010 and took on the job of resolving surface water floor protection in the area to prevent this from occurring again.
As part of the prevention project, Lincolnshire Country Council’s drainage team used Duraplas® recycled plastic profiles and posts to build a low-level flood baffle. The aim of this project was to provide a vital last line of defence for a residential tower block and the surrounding social housing close to the River Witham.
Nathan Whitfield, Lincolnshire County Council’s Principal Drainage Engineer, explains that conventional flood barriers, such as bund or brick wall, were ruled out due to the number of utilities services buried underground close to the site, some of them quite close to the surface.
He says “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 depend 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 premanufactured 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.”
As there were multiple underground utilities below the project site, it was vital for Nathan and his team could adapt the project to the already established services. If it was not for the inherent versatility of Duraplas®, this may not have been possible and could have been very costly had the Council needed to reroute service lines.
Now completed, the flood baffle will hold back any low-level surface water flooding to ensure the neighbouring properties are fully protected. Any water contained in the baffle itself will drain away, or in a worst-case scenario, be pumped away before damage is caused.
The key benefit of using Duraplas® this project is its rot-resistance, making it perfect for water-adjacent applications. With the added benefits of no shrinking, cracking, colour and chemical leaching to maintain its lifespan and prevent impact upon surrounding environments, Duraplas® is a fantastically durable material which can be applied to a range of projects.
Whitfield concludes with “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