Projects

Low Crosby Flood Risk Management Scheme

Delivering carbon-negative flood defense infrastructure

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Lowering of the flood embankment, the bare earth representing the reprofiled embankment which was seeded to allow grass cover to re-establish itself
Visualization of how Low Crosby will remain dry for a flood event equivalent to Storm Desmond with the completed scheme in place

The Environment Agency wished to implement a cost-effective, sustainable flood risk reduction scheme for the Low Crosby community. To achieve this, they commissioned Jacobs to leverage our multi-disciplinary professional services, including hydraulic analysis, engineering feasibility assessment and design, environmental assessment and project management, along with our comprehensive knowledge of the local area and wider river catchment. The scheme adopted an entirely nature-based solution to substantially and sustainably reduce flood risk, with high resilience to climate change, while delivering long-term benefits to the health and wellbeing of the community.

Low Crosby is on the right bank of the River Eden, five kilometers northeast of Carlisle in Cumbria, U.K. The community has experienced repeated flooding, most notably following Storm Desmond in December 2015, when 60 properties were flooded. The Environment Agency aimed to reduce flood risk in a cost-effective, sustainable way. The scheme’s objectives aligned with the United Nations Sustainable Development Goals (U.N. SDGs) to:

Deliver key flood risk management outcomes
Protect and enhance the environment
Promote health and wellbeing
Implement a sustainable, low-carbon solution

“The sustainability challenges on this project were around delivering a low-carbon flood risk management solution while taking into account climate change, enhancing the natural environment and delivering social value. Jacobs designed an entirely nature-based solution which unlocked the option to “build less” and “deliver more,” avoiding construction works within the community and delivering long-term environmental and carbon benefits.”

Ross McKeown

Project Manager, Environment Agency

Hydraulic model outputs from Jacobs’ Flood Modeller
The first post-construction floodplain inundation event in January 2023

The solution involved reprofiling a three kilometer private embankment on the left bank of the river. This reconnected 185 hectares (457 acres) of floodplain, increasing local conveyance capacity and significantly reducing flood levels in Low Crosby village. The scheme was delivered at a design and construction cost of £2.6 million ($3.2 million).

Reconnecting the floodplain was only possible with the support of the landowner — whose agriculture business had benefitted from the private embankment — along with Natural England and the affected residents and businesses. By working closely with the landowner and Natural England, the team unlocked the option to build less and deliver more, reducing the need for disruptive construction works in the village, while delivering long-term environmental and carbon benefits. Community engagement was a key enabler of success, requiring careful management of conflicting stakeholder views to achieve consensus.

This was a fully digital project, using the latest innovations in this field, including:

Piloting the Environment Agency’s library of smart, parametric 3D model components
Using design model data to control the earth-moving plant
Developing an automation tool to quickly extract digital asset data

The scheme also contributed to research and development data, with outputs from the economic model informing the client’s Carbon Impacts Tool, a method for assessing carbon emissions caused by flooding. The whole-life carbon assessment used Jacobs-developed analysis methods to estimate the impact of land use change on carbon emissions.

The project’s key benefits significantly contribute to the Environment Agency’s net-zero goals and align with multiple U.N. SDGs. These efforts are reflected in the project’s Excellent CEEQUAL rating.

Low Crosby FRMS - Visualisation fly through of the proposed scheme and the protection it affords

0:00

Video courtesy of Newground Flood

95

Homes with substantially reduced flood risk
£ 15.5

Million ($19 million) of quantified economic benefit, including £8 million ($9.8 million) of natural capital benefit
185

Hectares (457 acres) of floodplain reconnected
3

Kilometers of protected river habitat restored
30000

Tonnes (33,069 U.S. short tons) of carbon dioxide sequestered
0

Tonnes of steel or concrete used

Key team members

David Webborn, Design Manager

David acted as Design Manager for the project and led the development of the delivered solution from the initial feasibility stage through to detailed design and construction.
Adam Parkes, Technical Director of Flood Products

Adam is a lead hydrologist and hydraulic modeler and leads the development of Jacobs’ suite of flood modeling software products. Adam was Jacob’s hydrology and hydraulic modeling lead on the scheme.
Ian Knight, Project Verifier

Ian is Jacobs’ engineering design coordinator for Environment Agency’s project delivery program in Northwest England. He acted as Jacobs’ project verifier on this scheme, providing independent technical reviews and advice to the project team.
Liam Holmes, Civil Engineer

Liam joined the project team as a graduate civil engineer at the commencement of detailed design. He authored most of the technical deliverables that enabled the scheme to be constructed.
Ed McGurin, Project Manager (Appraisal)

Ed is a director of project management and acted as project manager for the scheme during the appraisal (feasibility) stages.
Catherine Baxter, Project Manager (Design)

Catherine is a principal project manager and was Jacobs’ project manager during the detailed design stage. She also acted as assistant project manager during the appraisal stage.
Gail Rainford, Ecologist

Gail is an ecologist and led the crucial ecological assessment work that helped identify the multiple ecological and carbon benefits associated with the scheme.
Steve Yates, Principal Designer

Steve is a safety in design specialist and was Jacobs’ principal designer advisor for this project, carrying out design safety reviews and providing advice on technical safety to the client and the project team.
Martin Johnson, Landscape Architecture Lead

Martin leads the Warrington landscape team and was responsible for the team’s work on the Low Crosby project from appraisal stage through to detailed landscape design.
Judith Cudden, Geomorphology Lead

Judith was the fluvial geomorphologist lead and undertook the Water Framework Directive assessment to secure compliance with legislative requirements and ensure the scheme provided environmental benefits.