Land & Water have been appointed by Wandsworth Council to remove the half-tide weir on the River Wandle at Wandsworth. The project will use a range of Land & Water’s specialist equipment including a spud pontoon with marine crane, a JS 145 long reach excavator, to complete the dredging. The excavator is equipped with a lidded bucket to reduce turbidity when dredging and the excavator is dredging to profile with a 3DGPS Prolec digging system all provided installed and set up by Land & Water Plant Hire. We are also providing the barges to move the silt to the unloading area and these are being discharged with a 22 tonne long reach excavator with clamshell grab, taking 6 months to complete. This will allow the tidal river to return to its natural state to support biodiversity in central London.
The photograph is of the Land & Water’s own design mini amphibious machine which is being used for the first time on this project to collect sediment samples.
Sediment has built up behind Wandsworth half-tide weir over its 25-year lifetime. This build up has buried the natural gravel river bed under a deep layer of debris and silt. Removal of the weir and these silt deposits will take out the barrier between the Wandle and the tidal Thames.
Natural tidal action at the river mouth will scour fine, muddy sediment from the area and restore the gravel river bottom, restoring valuable subtidal and intertidal habitats for fish, invertebrates and wading birds. The improved water flow will help restore a wildlife habitat measuring roughly a hectare in size that has the potential to become a spawning area and nursery for young fish.