Bloors Homes, Ampthill, Bedford.
Channel Repairs to a storm water channel.
- 300mmɸ x 2M Filled Rock Rolls
- Ekotex07 a non-woven Geotextile
- Geoweb a 75mm deep Confinement System
- Geocoir 400… 100% Coir Erosion Control Blanket
After a number of heavy storm events the channel slopes, which consisted only of fine sandy soils, slumped and eroded badly under fast & high flow water conditions. There was no established vegetation on the slopes and the silts were washed down the channel and into the main drain, which was not acceptable. The situation was also giving concern to the local residents as the banks were eroding at a fast pace endangering pathways, fencing and gardens.
A solution was put forward by Terraqua environment solutions, accepted by the consultant & main contractor so that site won materials could be used instead of having to import materials. The solution was to use 2 No. granite filled rock rolls as a protection lining to each side of the channel, one on top of each over and secured into place with HD steel fixing pins. The slopes were regraded to 45°, once smooth the Ekotex07 geotextile was laid on top of the newly formed slopes, then the Geoweb 75 was installed with anchor trenches at the top & bottom of the slope. On this occasion tendon were used to save costs on pins and installation time. The Geoweb was then filled with a quality seeded soil , the system was completed by covering the top soil with an erosion control blanket made from 100% coir & pinned into place. The blanket prevented further soil loss from the slopes whilst at the same time helping to germinate seeds & encorage vegetation growth on the slopes.
After 6-9 months the slopes had fully vegetated, the rock-rolls continued to protected the sides of the drainage channel under fast flows and flood events preventing any erosion at the toe of the slope. The new system is now providing risk free evacuation of storm water from the site.
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