Case Study: Protecting Critical Dam Infrastructure
Culvert Jetting & CCTV Inspection Works
Critical infrastructure doesn’t fail overnight. Over time, sediment, calcite deposits and debris can restrict drainage systems, reducing their ability to perform as intended and increasing the risk of long-term deterioration. Left unchecked, relatively minor issues can develop into far more significant maintenance challenges.
That is why Dŵr Cymru Welsh Water commissioned a programme of specialist drainage maintenance across three of the Elan Valley dams:
Caban Coch
Pen y Garreg
Craig Goch
Working alongside principal contractor envolve infrastructure, Arch Services was appointed to restore the operational performance of the pressure relief drainage network while providing a detailed understanding of each asset’s condition.
Images From The Project
Understanding The Asset Before Carrying Out The Work
Rather than simply cleaning the drainage network, the project followed a structured inspection-led approach.
Each pressure relief well was first surveyed to establish its condition. Where required, the drainage lines were cleaned using high-pressure jetting before being re-surveyed using specialist CCTV equipment to confirm functionality. A detailed report was then produced for every drain, providing Dŵr Cymru Welsh Water with clear recommendations for future maintenance and asset management.
This approach ensured the project delivered more than immediate maintenance. It created valuable asset information that will continue to support future investment decisions.
Working In A Challenging Environment
Projects within operational dam infrastructure present unique challenges.
Heavy calcite deposits and sediment had significantly reduced access through sections of the pressure relief drains, requiring multiple cleaning passes before full flow could be restored.
Access within the dams also required specialist confined-space procedures, with Mines Rescue Services providing trained rescue personnel, entry control and emergency rescue cover throughout the works. Adverse weather conditions added further complexity, requiring close coordination between all parties involved.
The Repair Approach
Arch Services used high-pressure jetting equipment to remove accumulated silt, calcite deposits and debris from the pressure relief drains.
Vacuum tankers removed the loosened material throughout the process, preventing downstream blockages and ensuring the system remained operational. Where heavy deposits were encountered, multiple cleaning passes were completed until full flow was restored.
Following cleaning, specialist CCTV micro-wheel units were deployed to inspect each drain, capturing high-definition video footage and confirming the effectiveness of the works.
Arch Services In Action
The Final Result
The programme successfully restored the operational performance of the drainage assets across all three dam locations while providing Dŵr Cymru Welsh Water with detailed information about the structural condition of the network.
The project delivered:
Restored hydraulic performance across the drainage network
Removal of sediment, calcite deposits and debris
Comprehensive CCTV inspection records
Early identification of structural defects
Improved information for future asset management
Reduced long-term maintenance requirements
Minimal disruption through efficient project delivery
The quality of planning, safety and delivery throughout the project was recognised with Dŵr Cymru Welsh Water’s Team of the Month award.
Why The Arch Services Approach Matters
For Arch Services, this project demonstrates the importance of looking beyond the immediate maintenance task.
The value was not simply in pressure jetting the drainage system. It was in understanding the condition of the assets, proving functionality through CCTV inspection, providing meaningful data for future maintenance and delivering the works safely within a challenging operational environment.
This capability is supported by Arch Services’ wider in-house expertise across drainage, utilities, local authority, rail, commercial and industrial environments. From CCTV surveys and asset mapping through to liquid waste removal, civil engineering, traffic management, robotic equipment, no-dig solutions and complex lining works, Arch Services can support clients through multiple stages of investigation, planning and delivery.
That matters because critical infrastructure demands more than reactive maintenance. It requires informed decisions, specialist capability and a contractor that can help protect vital assets for the long term.
Specialist works. Difficult environments. Trusted delivery.
Contact Arch Services For Specialist Support
If you are after specialist infrastructure repair, or any other of our commercial or domestic services, such as blocked drains, CCTV Surveys, Traffic Management or our Civil Engineering services, then please do not hesitate to contact us by call 0800 707 6771 or email us at info@archservices.co.uk. Our team are reachable 24/7 and on hand to help. We look forward to hearing from you.
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