Installing Vegetated Wall Systems at Ebbsfleet Garden City
About Ebbsfleet Garden City
Set to deliver 15,000 new homes by 2035, Ebbsfleet Garden City is a brand new town following in the footsteps of Letchworth and Welwyn. Being built on a vast brownfield site, this modern garden city is conveniently connected to Bluewater Shopping Centre on one side and Ebbsfleet International Railway Station on the other (with Paris just two hours away). A true vision of connectivity and infrastructure, married with swathes of green spaces and natural environments, Ebbsfleet Garden City in Kent will become a new benchmark for urban planning.
A former quarry—cement from which contributed to the construction of the Channel Tunnel and QEII Bridge—the entire thousand-acre site is almost completely enclosed by a chalk cliff (as high as 180ft in places).
On the south side of the city sit two vast lakes providing drainage, wildlife habitats and space for recreation. To aid in the development of these lakes by way of improving their recreational accessibility, we were contracted to install a series of vegetated wall systems designed to provide a soft engineering solution to bank creation and stabilisation.
Improving accessibility to water
Central to Sir Ebenezer Howard's 1898 vision of the garden city model was, alongside a strong economic framework, to pull together the best elements of the countryside to create the perfect living environment.
We’re strong believers that time spent close to water (if not in it!), is time well spent. With that in mind, we’re keen to make water bodies more accessible for everyone, making safe access to water a key component of a healthy lifestyle – something we’re sure Ebenezer would have approved of!
At the Ebbsfleet Garden City site, an interlocking vegetated wall system allowed us to cut away land in order to create the impact of a protruding jetty but with the stability of firm ground. We also created the perimeter walling for a lakeside bird hide and the boundary for a viewing area, all without the need for any hard engineering solutions.
Vegetated Wall Systems
Manufactured in the UK, the flexible walling is made from a UV stabilised, needle punched non-woven geotextile. Doubling as a filtration system, the permeable material allows the passage of plant roots, further stabilising the bank behind the wall.
A highly versatile laying system, the bags can be employed to build walls up to 10m high. Furthermore, the system can be used for applications including contouring and terracing, landslip repairs and shoreline and river restoration.
Here’s a cross-section of the installation at Ebbsfleet Garden City.
Cross-section of gravity build with wraparound details (1:30)
Installation
With the water drained, earth is excavated to accommodate the base layer, walling and backfill.
Following excavation, subsurface bags are placed on a deep layer of compacted stone (minimum 150mm).
By offsetting each new layer of bags, we maintain a 70° angle for the profile.
Interlocking plates are fixed between each tier, while layers of wrap-around Geogrid reinforce the level at three-course intervals, extending a minimum of one metre behind the bags.
Clean 20-40mm graded granular fill (suitable for Series 600 Highway Works) is backfilled and compacted, in this instance to a span of 1500mm-2700mm.
Upon structural completion, the wall should be hydroseeded – something our team can do for you.
Hydroseeding ensures the surface is fully covered to promote the best possible vegetation growth. The mix can be used to suit existing nearby vegetation or to help introduce new species.
Give us a call to discuss if a vegetated wall system is a suitable solution for your project.
