Full stream ahead

A group of Enfield residents are working together to improve a local stream and help boost wildlife, write Frances Dismore and Alison Archer

Firs Farm Wetlands

The popular wetlands area recently opened at Firs Farm in Winchmore Hill is now being used as an example for other parks and open spaces to follow (credit James Cracknell)

Those who observed satellite images recording the progressive effect of this summer’s heatwave on London may have noticed that as our city’s green spaces scorched brown, our waterways turned green.

It seems we’re so estranged from our rivers that we’re unable to interpret conspicuous indicators of environmental calamity, even when they are visible from space. As social media wondered as the ‘Astroturf’ duckweed blooms proliferated, fish were dying. How uncanny that it was our iconic, critically-endangered, red-listed eels, surfacing from the anaerobic, polluted depths dead, that spelt out the home truth.

Fortunately, we can build interventions in Enfield to reduce the diffuse pollution blighting our waterways and improve our community’s and our wildlife’s resilience to climate change. We have an unprecedented opportunity in north London to build a matrix of Sustainable Drain Systems (SuDS) to improve water quality on a catchment scale while augmenting local flood defence measures to protect people’s homes.

SuDs are constructed wetlands which can be built into the hard-landscaping of roads or housing developments as planters or swales. They can be landscaped into parks as rewilded spaces for recreation, outdoor classrooms, and habitat for wildlife. SuDs slow stormwater run-off, allowing sewer networks to function within capacity, averting emergency discharges of sewage into our rivers.

Often parks are sited on floodplains, here SuDS can be landscaped to create greater capacity to store floodwater. The wetland plants filter out grit, oil, microplastics, and heavy-metals from road run-off – preventing these from polluting our rivers. The plants also absorb excess nutrients from sewerage introduced by incorrect plumbing, mitigating extreme duck weed and algal blooms.

Residents, facilitated by the leading waterways charity Thames21, have used their local knowledge to identify areas to site SuDS in Enfield and other parts of the Lower Lea catchment in London. Using open-source data on geography, space, weather, land use, water quality, and sewer networks, plus a computer modelling programme which simulates the flow of rainfall and run-off, 34 feasible sites have been identified.

Pymmes Brook

At Tile Kiln Lane, Pymmes Brook is very pretty, but very polluted (credit Vincent Lo)

The Pymmes Brook in Enfield is one of the streams that feeds into the River Lea, but it is currently one of the dirtiest in the country. Working with communities in the river’s catchment area, as well as Enfield Council and Thames 21, a group of residents want to install a new wetlands area that will clean the water naturally, reduce flood risk, increase biodiversity, and improve Enfield’s open spaces.

The project is a fantastic opportunity to improve, not just our local green spaces, but the whole river, and is an amazing opportunity to have a real and positive impact on our environment.

By working with people along the course of the river we can make our rivers and open spaces lovelier. We’d like to see kingfishers, herons and egrets on the river, take our kids pond-dipping, and build outdoor classrooms and riverside paths.

Vicci Midwinter is one of the local people involved. She said: “Pymmes Brook, like many of London’s rivers, is heavily polluted, mainly by the run-off from roads and by sewage mis-connections, but environmental crime is also a problem.

“We want to change how people think about their rivers, to understand that by getting involved we can do something about it!”

Eamonn Cannon, another resident working on the project, said the group were using a computer programme developed by Oxford University to model the impact that building wetlands can have on water quality. “We’ve shown that it will improve by a whopping 28 percent, which would transform Pymmes Brook from one of the dirtiest rivers in the UK to one whose water quality is rated as ‘good’.”

The group is now calling itself the Pymmes Brookers (short for ‘Pymmes Brook Restorers’). They want to construct 16 wetlands along the river’s catchment. Prospective sites in Enfield include Arnos Park, Tatem Park, and Tile Kiln Lane Green Space, in addition to wetlands already planned in Broomfield and Pymmes Park.

“There’s lots to do,” says volunteer Laura Hooke, “I love working with a group, outside, doing something practical to make our outdoor spaces more enjoyable for us all.

“We’d love people to help us spread the word, and we’re going to need help with lots of things, from planting reedbeds, to litter-picking, and all sorts.”

Peter Leedham is part of another group that is doing something similar for Salmon’s Brook, which also runs through Enfield on its way to the River Lea. He said: “We’d love to hear from people who live or work next to Salmon’s Brook to help us make it a part of our environment that we can all enjoy!”

To find out more and to get involved with the Pymmes Brookers:
Email [email protected]

To help with the group working on Salmon’s Brook:
Email [email protected]