Brearley Fields, Mytholmroyd: An innovative wetland project to enhance naturally managed flood risk and create valuable wildlife habitats

By Sam Speight

Work to create a wetland nature reserve commenced at Brearley Fields in Mytholmroyd last month. The project will transform the former playing fields into a valuable wetlands habitat and increase floodwater storage on the floodplain of the river Calder.

The wetland nature reserve will work with natural processes to enhance naturally managed flood risks. Many small‑scale Natural Flood Management (NFM) interventions, taken together, can result in a significant amount of water being temporarily stored, or attenuated, during storm events. Depending on the severity of the flood event, the new wetlands will boost floodwater attenuation by up to 3000m3 . On its own, the impact will be minor, reducing nearby peak flood levels by a couple of centimetres. However, the work is another piece of the slow the flow puzzle, which alongside the work of Slow The Flow, the Environment Agency, the National Trust, Calder Rivers Trust, local landowners, and others in the Calder Valley, will contribute to collectively reducing the scale and damaging effects of future flood events.

Brearley fields wetland project information board

A Brief History

Until the early 1960s, the river Calder meandered through Brearley Fields. Evidence of the old meanders are still visible in the landscape at the far end of the fields. The river was straightened (channelized) and an embankment built, disconnecting it from its floodplain except during times of flood. The fields were then used as playing fields by Calder High School, until persistent flooding led to the eastern half of Brearley Fields being left abandoned for the last 10 or so years. 

Since then, the Mytholmroyd Flood Alleviation Scheme (FAS) has been completed, offering greater flood protection to 400 homes and businesses. The FAS increases the conveyance of water downstream to Brealey Fields, and the Rochdale canal overflow, a key component of the scheme, spills onto Brearley Fields during periods of high flow. This, combined with the impacts of climate change, which will likely increase the frequency and magnitude of flood events, means Brearley Fields will more wet, more often.

In 2017, Calderdale Council sought a sustainable future for the fields and worked with several organisations to explore the development of the site. The idea to utilise the fields as a wetland was first made to Royd Regeneration, who have championed the project ever since. The fields were also identified in opportunity mapping carried out by Slow the Flow as an area that could contribute to flood alleviation through natural interventions. Community consultation demonstrated strong support locally for plans to create a new wetland nature reserve. 

Calder Greening Projects

In 2018, the Council successfully bid for £1.3 million of European funding to invest in green spaces in Calderdale as part of the Calder Greening Programme. Working alongside project partners at the Yorkshire Wildlife Trust and the Environment Agency, Calder Greening has achieved the following:

  • Mytholmroyd Public Green Spaces. Enhanced public green spaces at St Michael’s Church and lower Cragg Brook as part of the flood alleviation scheme. 
  • INNS. Tackled invasive non-native species (INNS) across Calderdale, including Japanese Knotweed and Giant Hogweed over several years
  • River Restoration. delivered in-channel restoration works to improve the health of rivers and streams around Halifax.
  • ‘North loop’ at Cromwell Bottom nature reserve. Created new ponds, habitats for ground nesting birds, access footpaths and educational facilities for school visits.
  • Milner Royd nature reserve and Copley Valley flood lagoon. Built ponds, created a wildflower meadow and orchard with improved access and seating areas.
  • Brearley Fields Wetland Nature Reserve

After securing the necessary permits and consents, work commenced at Brearley Fields in March 2023.

Brearley Fields: Designed for nature and people

The wetland, on the floodplain of the river Calder, will feature two large new ponds which will be a magnet for wetland birds and invertebrates. A huge scrape (temporary pond), connected to the river will occupy much of the site, and will fill and drain as river levels naturally rise and fall. Sections of the existing flood embankment will be removed, improving connectivity between the river and its floodplain, re-establishing natural, dynamic river processes. Backwaters of the river will be enhanced, providing refuge for juvenile fish which thrive in their warm, shallow waters. 

Brearley Fields, including the football pitches at the western end, are regularly inundated, often resulting in some, or all, of the pitches rendered unplayable for many of the winter months. By removing sections of embankment at the eastern end of Brearley Fields and creating a new raised bund separating the wetlands and football pitches, modelling demonstrates that the wetlands will offer significantly improved flood protection to the pitches during periods of high flows, or more minor flood events (50% AEP/ 1 in 2-year flood). The pitches will flood, as they currently do, during more severe flood events, performing their important role as a floodplain flood storage area. Floodwater will then drain into the wetlands, passing through reedbed filters, cleaning the water before it re-enters the river.

Fencing will limit disturbance around the sensitive new habitats. Ground nesting birds, such as lapwing, are found locally, but are particularly susceptible to disturbance. Nationally their population has declined by more than 80% in the last 60 years. Fencing will allow birds such as lapwing to raise their young without being disturbed and allow dog walkers to continue walking their four-legged friends at Brearley Fields. 

A new footpath will significantly improve access onto the fields, and benches will provide a spot to rest and admire the noisy sand martins, diving kingfishers or, if you’re lucky, a visiting otter.

Volunteering Opportunities

Following the completion of the main construction works in early May, habitat creation works will follow, creating a diversity of habitats that boosts local biodiversity. We’ll host several volunteer days over the next few months where we’ll sow a floodplain wildflower meadow, plant reedbeds and other wetland plants, and plant trees which will thrive in the boggy conditions.

Please get in touch if you’d like to be involved in creating and caring for the new wetland nature reserve and help leave a lasting positive impact in your local environment. Please email or follow our Calder Greening Facebook page to keep up to date with the latest activities at Brearley Fields. We look forward to welcoming you to Calderdale’s new wetland nature reserve soon.

Brearley Fields is part of Calder Greening, a programme of works to complement the Calder Valley Flood Alleviation Schemes with naturally managed flood risk, part funded by the European Regional Development Fund.

The work is part funded by the Northern Powerhouse, a key aspect of the Government’s approach to addressing the productivity gap in the North and ensuring a stronger, more sustainable economy for all parts of the UK. Alongside over €1.5 billion of European Regional Development Fund support for businesses and communities across the North, the government has awarded £3.4 billion in three rounds of Growth Deals across the Northern Powerhouse.

Sam Speight

Environmental Projects Officer, Calder Greening