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Thames Water: Walthamstow Wetlands

Creating a community for people and wildlife through the Walthamstow Wetland project

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  • What we know
  • What we’re doing
  • What it’s worth

What we know

Walthamstow Wetlands is a fully operational site for Thames Water serving 3.5 million customers in London with drinking water every day.

It is a peaceful site and is of international importance for its bird life and is designated as a site of international importance for wetlands by the Ramsar convention, a Site of Special Scientific Interest (SSSI) and a Special Protection Area (SPA).

With over 300,000 people living in walking distance of the wetlands – most without gardens and who didn’t have easy access to Nature – the site had potential to be an especially unique resource for locals.

One challenge posed was how to open it up to more local people and significantly increase the number of visitors, without affecting the operational value or negatively impacting wildlife at the nature reserve.

In a unique partnership with London Wildlife Trust and London Borough of Waltham Forest, the 211-hectare operational reservoir site was opened to the public in October 2017 allowing all the community to access the Wetlands site to experience the reservoirs and their nature and learn about and appreciate the site’s natural and industrial heritage.

Walthamstow Wetlands is one of the largest urban wetland nature reserves in Europe and is important for wildlife due to its position within the Lee Valley. It serves as a byway for migrating, wintering and breeding birds and over 300 species of plants, including the marsh marigold and lesser bulrush which are uncommon in Greater London.

Alongside providing improved access to nature and education for local communities and visitors from further afield, the project has been delivering biodiversity enhancements and management of INNS (Invasive Non-Native Species).

What we’re doing

Ecological enhancements as part of the Creating  included:

  • Creation of 1.9 hectares of new reedbeds around the central reservoirs to increase breeding bird habitats and fish refuges.
  • Opening up the canopy and planting riparian vegetation encouraged water voles.
  • Addition of three new ponds to increase habitat for breeding amphibians.
  • Investing £800,000 on a 1440m2 floating island, to attract wading birds, with four new tern rafts on site.
  • Building a sensory garden with raised pond for less able-bodied visitors.
  • Planting native trees across the site to help support UK targets.
  • Providing active terrestrial and aquatic invasive species management (including Giant Hogweed).
  • Installation of green infrastructure including a green roof seeded with wildflower mix to attract bees.
  • Establishing Wildflower Turf on site, to create high distinctive grassland for invertebrates.
  • Building a Swift Tower on the Engine house and installed rough render inside the tower to support bats.
  • Installing Habitat Gates to support seasonal routes around site.
  • Enhancing 1.3 hectares of meadow grassland.
illustration of three birds in navy

What it’s worth

We’re pleased to have achieved our aim of opening the wetlands to the public, providing many social benefits while allowing biodiversity to flourish. In 2020 alone we welcomed 650,000 visitors to site and reached our 1 millionth visit during the summer.

Access to Walthamstow Wetlands became even more important during the Covid-19 crisis where we made the active decision to keep the site open to the local community when other publicly available spaces in London were closed. It provided a space to explore the outdoors, birdwatch, exercise, and find solace in unprecedented circumstances.

The actions listed above show the actions taken to protect and increase biodiversity on the site.

Our partners at Walthamstow Wetlands are committed to continue to monitor biodiversity with on-going surveys that measure bird numbers and record the chosen habitats of migrating birds.

This will be further investigated and measured using satellite imagery and drone survey technology to give a biodiversity net gain in unit value for the site. The biodiversity units generated will feed into our commitment with Ofwat to enhance biodiversity on our estate by 5% by March 2025.


Since Walthamstow Wetlands opened, it’s become an important part of the community and people’s lives. During the two lockdowns, visitors were supported by a dedicated on-site team and volunteers, who did a brilliant job managing the extra numbers and also taking time to talk to visitors who may have been feeling down in these difficult times.”

Sarah Bentley Thames Water CEO