Galliford Try
Pitfodels Service Reservoir (2025)
Pitfodels DSR fully reinstated after waterproofing and refurbishment - Courtesy of Morrison Construction
Under the DV2 Framework, Scottish Water appointed Morrison Construction as the Principal Contractor and Principal Designer to execute the Treated Water Storage (TWS) Programme . This ambitious programme spanning multiple years, focuses on refurbishing and enhancing the resilience of critical treated water storage infrastructure across Scotland. The programme aims to ensure the continued supply of high-quality drinking water while embracing sustainable and innovative engineering solutions. The Pitfodels Distribution Service Reservoir (DSR) Project exemplifies the success achieved under this framework, demonstrating how a proactive, collaborative approach can deliver significant cost, programme, and carbon savings. Through innovation and an intelligent engineering solution, the project not only extended the lifespan of a vital asset, but minimised network disruption, reduced embodied carbon, and improved resilience for future generations.
Pitfodels DSR – Scope of work
Located in Aberdeen, Pitfodels DSR was construction in 2002 and serves a population of 225,000 people. Measuring 63m long x 44.5m wide x 6m high, it has a working storage volume of 14.55 ML. The primary issue was water ingress which could potentially lead to water quality risks, which require MorrisonConstruction to undertake a 19 week project valued at £1.6m, with the following scope:
- External waterproof membrane installation (Fosroc Proofex 3000).
- Concrete repair works.
- Overburden removal and reinstatement.
- Drainage improvements.
- The Technocover Ltd access hatch resealing.
- Solar panel removal and reinstallation.
(left) Solar panels removed at start of works and (right) inside the reservoir at the start of the internal refurbishment works – Courtesy of Morrison Construction
Pitfodels DSR – Additional Scope
An inspection upon entering the tank revealed severe deterioration of the roof structure, necessitating significant reinforcement measures. This £1.8m in additional work required an 85 week extension (from initial 19 weeks). A collaborative decision-making process involving Scottish Water, Morrison Construction, subcontractors, suppliers, and design professionals was undertaken to determine the optimal solution for addressing the structural deficiencies including innovative low-carbon reinforcement of the tank soffit and birdcage scaffolding for safe soffit access.
Pitfodels DSR – Supply chain – key participants
- Project delivery: Morrison Construction
- Designer: Allen Gordon LLP
- Waterproofing, structural repairs specialist: Fraser Bruce Group
- Civil contractor: Macari Hill Civil Engineering
- External waterproofing: Fosroc
- Internal soffit/roof repairs: Sika
Challenges
The key challenges included:
- Limited site information: No as-built records, restricted surveys before tank decommissioning and project delivery.
- Structural failures: Bespoke beam and block construction deteriorated due to water ingress, freeze-thaw cycles, and block delamination, leading to falling debris.
- Environmental risks: Cold weather posed challenges for specialist waterproofing materials.
Scaffolding in place for the reservoir internal refurbishment – Courtesy of Morrison Construction
Engineering solution: Internal structural strengthening
The solution ensured the existing beam and block construction functioned homogeneously.
- Concrete repairs: Hollow core blocks and precast beams repaired using Sika repair mortars.
- Carbon Fibre Reinforcement:
- Sika CarboDur Grid C System:
- Bi-directional carbon fibre grid (CarboDur 300 Grid) applied to the soffit.
- Encapsulated with two layers of Sika MonoTop-3200 Grid mortar.
- Total thickness: 6mm.
- Sika CarboDur S626 plates:
- Pultruded carbon fibre plates bonded to transverse beams using Sikadur-30 epoxy.
- Broadcast with kiln-dried quartz sand for enhanced adhesion.
- Sika CarboDur Grid C System:
- Surface protection:
- Sika MasterSeal 588 applied to encapsulate the strengthening systems.
Engineering solution: External design enhancements
- Thermal protection: 100mm insulation to prevent freeze-thaw cycles.
- Load reduction: Overburden thickness reduced by 115mm, minimising roof stress.
- Waterproofing enhancements:
- 5mm Proofex 3000 membrane on Proofex primer.
- Two 8mm Proofex Sheetdrain 80 layers for improved drainage.
- 5mm self-levelling compound for surface refinement.
Refurbishment works underway – Courtesy of Morrison Construction
Stakeholder collaboration, community engagement & economic opportunities
Regular communication with the local council facilitated necessary approvals and permissions. and early stakeholder engagement ensured the community were involved from concept until completion.
A local Morrison Construction team was employed which included two trainee civil engineering graduate apprentices (the project provided invaluable experience) and the team utilised the local supply chain, with the overburden and drainage material being sourced from a local quarry. The project safeguarded the lifespan of this tank for the foreseeable future, mitigating future network disruption associated with a new roof or new tank construction.
Environmental considerations
- No demolition waste: The works avoided significant construction debris that would have resulted from a full roof rebuild.
- Preserved natural surroundings: There was no requirement for large-scale excavation meaning no disruption to the local ecosystem.
- Mitigated water quality risks: By preventing roof deterioration and leakage, the project safeguarded local water quality and protected drinking water supply.
- Digital transformation: The project was managed using Fieldview, Viewpoint, and Hypervine, reducing 99% of paper usage.
- Sustainable site operations: HHVO (hydrotreated vegetable oil) fuel wasused across the project, cutting CO₂ emissions from on-site plant and machinery.
Key Outcomes
- Significant cost & carbon savings: Instead of a costly £9 million roof rebuild, the tank was reinforced using lightweight carbon fibre, saving £5.6 million and preventing 300 tonnes of CO₂ emissions, compared with a roof rebuild also avoiding demolition and material wastage.
- Superior waterproofing extends asset lifespan: Drainage layers, insulation and waterproofing, reduce leakage risks, prevent future damage, safeguard water quality and reduce future maintenance.
- Lightweight, high-strength solution: Carbon fibre reinforcement enhanced structural integrity without excessive load.
- Minimal disruption: Existing structure strengthened without full roof reconstruction.
- Concurrent delivery: Initial works continued uninterrupted while soffit repairs were designed and implemented.
- Programme efficiency: 2.5 years saved compared to a full roof rebuild (4.15 years vs. 1.83 years for refurbishment) while maintaining water supply with minimal network impact.
- Mitigated network disruption: Strengthening works avoided a longer-term network-wide shutdown.
The internal works after project completion – Courtesy of Morrison Construction
Conclusion
The Pitfodels DSR refurbishment stands as a resounding triumph within the TWS programme, underscoring the unwavering dedication of Morrison Construction and Scottish Water to delivering high-value, low-carbon infrastructure solutions.
This project exemplifies the pinnacle of modern civil engineering – a cost-effective, sustainable, and technically advanced solution that fortifies public water infrastructure for decades to come. Morrison Construction, its delivery partners, supply chain, and Scottish Water have established an exemplary benchmark for asset resilience, low-carbon engineering, and innovation in water infrastructure delivery.
This project serves as a paradigm for future treated water storage refurbishments, demonstrating that astute engineering can drive efficiency, sustainability, and long-term value.
