IWA West London Branch

16 June 2021

The Partnership is a joint IWA West London/Canal & River Trust initiative for the care, conservation and restoration of the Hanwell Flight and Norwood Locks. The Partnership’s volunteer activities extend over one mile of the Grand Union Canal from the head of Norwood Top Lock (Lock 90) to the confluence with the River Brent below the Hanwell Flight (Locks 92 to 97). The Norwood Locks and the Hanwell Flight are separated by a 500-metre pound which is the site of Three Bridges, a Scheduled Monument and a rare intersection of canal, road and railway engineered by Isambard Kingdom Brunel.

Constructed in 1794 the Hanwell flight of locks together with the lock side ponds and the boundary wall of the former Middlesex County Asylum (completed 1831) is a Scheduled Monument. The locks and side-ponds at Hanwell are recognised as a non-statutory wildlife site due to the intrinsic value for wildlife and the associated connections to other important habitats including the River Brent corridor and the nearby public open space of Jubilee Meadow and Blackberry Corner managed by Ealing Council. The off side of the canal supports a diverse range of wildlife including amphibians, wetland bird species, aquatic vegetation such as reed beds, sedges, rushes and wetland trees including willow and poplar.

New floating ecosystem

The new floating ecosystem at the lock 97 side ponds follows on from a successful installation of similar floating beds at the lock 96 side ponds in 2020. The coir floating beds planted with a variety native wetland and marginal vegetation provide a transitionary habitat important for the newts residing within the ponds, and an easy means of movement between habitats for amphibians. They also provide a great spawning habitat for fish and habitats for insects such as dragonflies and damselflies.

At the task party the interlocking units were bolted together by IWA volunteers on the lock side before being planted with a variety of sedges rushes and reeds. Finally the beds were manoeuvred into the two side pond basins. A cable system will be used to tether the floating ecosystem to the rear wall of the side ponds and this is designed to accommodate variations in water level and future operational use of the side ponds by the volunteer lock keepers at Hanwell.