The restoration of the east marsh

East marsh after plastic debris removal, March 2021

The east marsh is one of two protected bird refuges at the Welsh Harp. Like the north marsh, it was extensively re-profiled in the late 1980s with public money to create a variety of marshland habitats for breeding wetland birds and wintering wildfowl notified under the reservoir's status as a SSSI.

With the funding needed for upkeep dwindling over the decades, the marshes were in a poor state at the start of 2021. Wheelie bins, rusting supermarket trollies, traffic cones, toys, tyres, off-cut timber and fly-tipped waste peppered the shallow wetlands.

Below the surface, a layer-cake of smaller plastics - bags, fabrics, wet wipes - and shredded micro-plastics sat in thick reefs of silt. Pools, islands, scrapes, channels and reed beds were clogged with sediment and litter, and invaded by fast-growing self-seeded willow.

Many breeding rafts on the east marsh were broken, unprotected and beached on the sediment deposits.

Following our sustained campaign for change, Natural England woke up to the crisis, and Canal and River Trust finally removed large items of debris from the marshes in early March 2021.

In November 2021, Canal and River Trust - following successful funding bids and consultation with campaigners - announced a new winter works programme for the east marsh. The works include a hydrographic survey and the removal of self-seeded willow to improve reed habitats and fringes, and further marshland plastic and debris clearance by boat.

The silt (technically, alluvium) is contaminated with hydrocarbons from urban road runoff. It has been unmanaged for decades, and is slowly filling the reservoir. Aquatic life has suffered and so have bird numbers. Protected diving waterbirds have been forced into deeper water away from the marsh.

In 2023, Canal and River Trust took silt samples. A direction connection was made with runoff from the nearby M1 entering the reservoir via poorly managed outfalls into the River Brent. The Trust used the findings as leverage with National Highways for a major restoration bid. We are optimisitic a large-scale dredging and habitat restoration project is in the pipeline.

We applaud the response of the Canal and River Trust. We hope this is just the start.