The Upper Don Flood Alleviation project focused on the detailed design of an extensive flood defence along a 2 km section of the River Loxley, which passes through a heavily industrialised and manufacturing area in Hillsborough, Sheffield. This area has a well-documented history of flooding, necessitating the implementation of robust and adaptive defences to protect local businesses and infrastructure. The defences included mass concrete walls, sheet piling, earth bunds, wall strengthening and waterproofing, balcony-style protection, bridge abutment plating, CFA piling, and removable flood barriers. The project required complex coordination across various constrained urban sites to deliver a practical solution that could adapt to ongoing changes in flood modelling. Key features included: A 2km section of the River Loxley History of flooding Complex coordination Multiple flood barrier systems utilised Services we provided Water Engineering & Flood Risk Civil & Infrastructure Engineering Ecology & Heritage Geotechnical & Ground Engineering Structural Engineering Our role BWB was responsible for developing the detailed design of the flood defence systems from initial sketches provided post-tender. This required extensive stakeholder engagement, with 17 separate landowners involved. Our role was to ensure that the final design met the hydraulic, structural, and environmental requirements while minimising the impact on local businesses and operations. Real-time monitoring Our engineers refined the flood model throughout the project to adjust the defence heights and profiles as new data became available. We also designed and coordinated multiple structural solutions, including bespoke wall waterproofing, bridge abutment plating, and removable defences, to respond to the unique constraints of each site. Ecological leadership BWB also led the environmental and ecological aspects of the design, developing mitigation measures such as riverbank planting for erosion control, fish spawning ledges, and badger sett relocation. Additionally, we incorporated the removal of a redundant weir to improve the river’s flow capacity and ecological connectivity. A challenging project The project posed numerous technical and logistical challenges. The 2 km stretch of river was lined with existing masonry walls and critical utilities that limited construction options. Many sites were heavily constrained, with limited access routes and active industrial businesses requiring minimal disruption to their operations. Additionally, the River Loxley is prone to rapid fluctuations in water levels, making design and construction planning complex. Agile flow assessments were required throughout the project to adapt the design to the river’s dynamic hydraulic behaviour. We also managed extensive stakeholder consultations to address the needs and concerns of the 17 landowners involved.