Case Study: Floating Edge Ecosystem on the Grand Union Canal at Hanwell for the Canal & River Trust
In 2012 The Canal and River Trust were seeking a restoration solution for a vertical edged section of the Grand Union Canal at Hanwell, just outside London. Permission to remove the edging or carry out in stream civil works had been declined due to the inherent flood risk and any reduction in the channels capacity.
Vertical hard edges are now common feature in waterway sections that flow through or near urban locations. Restoring waterways in urban environments is a challenging restoration setting; however it offers a great opportunity to achieve multiple benefits.
As a solution CRT selected a series of Floating Edge Ecosystem modules on the basis of price and quality, as the best solution to provide bank protection and habitat to restore the river’s edge without obstructing flow or navigability.
In December 2012 they were installed at the site, with sections fitting together using an adjustable angle stainless steel quick connect system, which allowed the curvature of the river to be precisely matched. A sliding guidepost anchoring system was utilised allowing the system to move smoothly up and down with the changing water levels. Additional benefits observed included cost savings, and short implementation time, and minimal disturbance to the site or surroundings. The marine engineering of the system has already experienced and effectively withstood highly variable water levels and high flow events.
The eco-system is now fully vegetated and provides a natural green soft edge system. The system delivers increased aquatic biodiversity, improved water quality by absorbing & breaking down pollutants, and creates a wildlife habitat for birds and animals whilst proving ideal cover for fish zooplankton underneath the floating ecology, the floating units also act as a breakwater against boat wash providing further protection against erosion.
See installation images below: Download Case Study (pdf) Biomatrix river restoration at Hanwell Case Study