The City of Hull is settled on flat land adjacent to the sea and close to sea level, making the region susceptible to intense flooding due to its surrounding valleys draining their rainwater into the basin in which Hull is built. Consequentially, in 2007, over 14,000 properties were affected by flooding in Hull. Therefore, in order to reduce future flooding, the Cottingham and Orchard Park Flood Alleviation Scheme (COPFAS) storm-water attenuation project was proposed to protect communities, businesses and local infrastructure in the areas of Cottingham and Orchard Park.

What we did

Pell Frischmann provided Civil, Geotechnical, Structural and Flood Engineering and Environmental Consultancy services for all stages of the project, from modelling through to outline and detailed design, obtaining planning permission, to on-site engineering, for a system of nine storage reservoirs, all in accordance with the Reservoirs Act throughout the Raywell Valley and Orchard Park, east of Hull.

Starting in 2016, the scheme was split and delivered into two phases:

Phase One: Design of control structures and a series of pipes and ditches to remove excess water from a watercourse and divert it to the storage reservoir in Orchard Park.

Phase Two: Design of eight flood storage reservoirs with control structures and connecting pipes and ditches cascading down the Raywell Valley.

Pell Frischmann’s multi-disciplinary capabilities allowed experts in the Flood, Geotechnical and Civil Engineering teams to provide innovative, cost-effective solutions, without compromising on the safety of the local residents. Our teams created a new channel by refurbishing two existing culverts underneath a railway line, easing the flow of floodwater to Orchard Park. Refurbishing, as opposed to building a newer, larger culvert, saved the client over £1M and minimised impact on the environment.

Our Environmental Consultancy services integrated mitigation and enhancement into the design and construction phases and included ecological surveys and appraisals, arboricultural surveys, and landscape visual impact assessments to support successful planning applications.

On complex, multi-faceted schemes, collaboration amongst clients, partners and stakeholders is key; millions of pounds were saved after extensive geotechnical testing and negotiations with Environment Agency and Yorkshire Water enabled sustainable re-use of existing clay to line the reservoir above the protected aquifer and build embankments.


Since Phase Two was completed in 2020, COPFAS has protected close to 4,000 homes and businesses in the local area from future flooding. Working alongside our partners, Pell Frischmann is proud to have delivered a scheme that creates value aligned with our noble purpose and sustainable aspirations.

Pell Frischmann’s Head of Environmental Management & Sustainability, Mark Duquemin:

I am rightfully proud of the teamwork, innovation and technical excellence that has successfully enabled the design and construction of COPFAS. Ours and our partners’ ultimate goal was to make sure the flooding disaster in 2007, and those before it, did not occur again. We hope our work on this major flood scheme will protect the community and allow the local economy to continue to grow and thrive.


ICE Yorkshire and Humber Awards 2020, Smeaton Award

Judges comments:

Most flood alleviation schemes provide measures on the line of a watercourse. This project impressed with the modelling and innovation deployed in linking several streams which contributed to the dreadful flooding of Hull in 2007 to convey excess water under a railway and main road to a single new storm water attenuation area.

ICE Yorkshire and Humber Awards 2021, Certificate of Excellence for the Centenary Award

Judges comments:

Pell Frischmann presented an innovative, high-quality design to service complex needs including introducing edge thinking on safeguarding of the water source protection zone, maximising attenuation of cascading reservoirs across multiple soil condition zones.

Shortlisted in NCE100 Awards 2019, Impact in Climate Resilience


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To find out more about COPFAS, please contact us through our form here.

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