The Hawick Flood Protection Scheme has secured Scotland’s highest civil engineering accolade, winning both the Project of the Year and Resilience Award at the Scottish Civil Engineering Awards held at the Edinburgh International Conference Centre on 29 August.
The £91.8 million infrastructure project, one of Scotland’s most significant flood defence undertakings, demonstrates advanced hydraulic engineering solutions that protect 970 properties while integrating sustainable transport infrastructure throughout the Scottish Borders town.
Project director Conor Price accepted the award alongside team members from CPE Consultancy, McLaughlin & Harvey, and Jacobs. The recognition follows the scheme’s earlier success at the Ground Engineering Awards in June, where it secured the UK Project with a Geotechnical Value category for addressing complex ground conditions at the Sandbed site.
The comprehensive flood defence system extends along the River Teviot and Slitrig Water, protecting against a 1-in-75-year flood event. The infrastructure comprises more than 6 kilometres of engineered flood walls and embankments, with structural heights calibrated to specific flood risk zones identified through hydraulic modelling.
Eight underground pumping stations automatically manage surface water during storm events, each equipped with monitoring systems that activate when water levels reach predetermined thresholds. The stations feature dual-pump configurations for redundancy, ensuring continuous operation during extreme weather conditions.
The project integrates a 7-kilometre active travel network, connecting previously isolated neighbourhoods through upgraded pedestrian bridges and a new river crossing. Three public spaces-Common Haugh, Wee Haugh, and Weensland Biodiversity Park-incorporate sustainable drainage systems that complement the primary flood defences.
Understanding Flood Protection Engineering: Technical Principles Behind the Hawick Scheme
Flood protection engineering combines hydraulic science, structural engineering, and environmental management to safeguard communities from water-related hazards. The Hawick scheme exemplifies modern flood defence design through its multi-layered approach to water management.
Engineers initiate flood protection projects by analysing historical flood data and developing computational models that simulate water behaviour under various conditions. These models incorporate topographical data, rainfall patterns, and river discharge rates to predict flood extents and velocities. For Hawick, engineers modelled a 1-in-75-year event-a flood with a 1.33% probability of occurring in any given year.
The modelling process utilises equations such as the Manning formula for open-channel flow, which calculates water velocity based on channel geometry, slope, and surface roughness. Engineers input digital elevation models and historical gauge data to calibrate these simulations, ensuring accurate predictions of flood behaviour.
Structural Defence Design
Flood walls and embankments form the primary defence line, with designs based on hydrostatic pressure calculations. Water exerts pressure proportional to its depth, creating forces that increase linearly from the surface to the base of any structure. Engineers calculate this pressure using the formula P = ρgh, where ρ represents the density of water, g denotes the acceleration due to gravity, and h indicates the depth of the water.
The Hawick walls incorporate reinforced concrete construction, with foundation depths determined by the soil’s bearing capacity and potential scour effects. Steel sheet piling extends below the visible structure, creating an impermeable barrier that prevents seepage beneath the walls-a phenomenon known as piping, which can undermine flood defences.
The eight pumping stations employ submersible pumps rated for specific flow rates measured in cubic meters per second. Each station’s capacity derives from catchment area calculations and design storm intensities. The pumps activate through float switches or ultrasonic level sensors, initiating when water reaches critical levels in collection sumps.
Pump selection involves matching performance curves to system requirements. Engineers specify impeller designs that maintain efficiency across varying head conditions-the vertical distance water must be lifted. Variable frequency drives adjust pump speeds to match inflow rates, optimising energy consumption while preventing motor burnout during extended operation.
The Sandbed section presented particular technical difficulties due to unconsolidated alluvial deposits. The ground investigation revealed variable soil conditions, requiring specialised foundation solutions. Engineers employed ground improvement techniques, including vibrocompaction, to increase soil density and enhance its load-bearing capacity.
Dewatering systems managed groundwater during construction by using wellpoint arrays to lower the water table temporarily. This prevented excavation instability and allowed concrete placement in dry conditions. Monitoring piezometers tracked groundwater levels throughout the construction process, ensuring that adjacent structures remained unaffected by drawdown.
Modern flood schemes incorporate sustainable drainage systems (SuDS) that manage routine rainfall while complementing emergency flood defences. The Hawick project features permeable paving, bioretention areas, and constructed wetlands that utilise natural processes to attenuate surface runoff.
These features reduce the burden on pumping stations during minor rainfall events, reserving mechanical capacity for extreme conditions. Detention basins within the new parks provide temporary storage volumes calculated using the modified rational method, which relates runoff to rainfall intensity, catchment area, and surface permeability coefficients.
The project team overcame significant geotechnical challenges at the constrained Sandbed site, where unforeseen ground conditions required adaptive engineering solutions. The team employed specialised drilling techniques and ground stabilisation methods to ensure structural integrity without expanding the construction footprint.
Construction sequencing minimised disruption to the town’s infrastructure while maintaining flood protection for occupied areas throughout the build phase. Temporary flood barriers protected vulnerable zones during wall construction, with contingency pumping arrangements ready for deployment.
The active travel network integration required careful coordination with flood defence alignments. Engineers designed multi-use corridors that serve as both maintenance access routes and recreational pathways. Bridge modifications strengthened structural capacity while preserving hydraulic performance during flood conditions.
The scheme’s design process involved extensive community consultation, with resident feedback influencing wall heights, surface finishes, and landscape treatments. Visual impact assessments guided the selection of materials that complement Hawick’s historic architecture while meeting structural requirements.
Environmental mitigation measures included fish passage provisions at pumping station outfalls and habitat creation within the biodiversity park. Construction timing was adjusted to avoid sensitive breeding periods for protected species identified during ecological surveys.
The project provided local employment opportunities and supply chain contracts, with the Scottish Borders Council prioritising regional contractors whose technical capabilities aligned with project requirements. Skills development programs provided training in specialised construction techniques, creating lasting expertise within the local workforce.
Post-construction monitoring will track scheme performance through a network of river gauges, rainfall sensors, and pump operation logs. Data collection will validate design assumptions and inform maintenance schedules. Annual inspections will assess structural condition, with particular attention to joint seals, mechanical components, and scour protection measures.
The scheme’s design incorporates climate change allowances, with additional freeboard accommodating projected increases in rainfall intensity and river flows. Modular construction techniques enable the future raising of defence levels if updated climate projections indicate an increased flood risk.
The Hawick project establishes benchmarks for integrated flood protection design, demonstrating how essential infrastructure can enhance urban environments while providing critical safety functions. The scheme’s success may influence funding models for similar projects, with its multi-benefit approach justifying substantial public investment.
As climate patterns shift and extreme weather events become more frequent, communities across Scotland are facing an increasing risk of flooding. The engineering solutions demonstrated at Hawick-combining structural defences, mechanical systems, and natural water management-provide a template for protecting vulnerable settlements while improving the quality of life for residents.
The project’s recognition at the Scottish Civil Engineering Awards validates the technical excellence achieved through collaborative design and construction processes. If similar schemes achieve comparable integration of flood protection with community infrastructure, Scotland’s towns could become more resilient to climate challenges while offering enhanced environments for residents and visitors.
TLDR
- Hawick Flood Protection Scheme wins Scotland’s top civil engineering award for Project of the Year
- £91.8 million project protects 970 properties from 1-in-75-year flood events
- Infrastructure includes 6km of flood walls, eight pumping stations, and a 7km active travel network
- Engineering solutions overcame complex ground conditions at constrained sites
- The project integrates flood defence with community amenities and sustainable drainage
- The scheme demonstrates advanced hydraulic engineering and climate adaptation strategies
