Vyrnwy Dam Monitoring: Overcoming Extreme Environmental Challenges in Wales, UK
This case study showcases SOCOTEC UK and Ireland’s innovative approach to overcoming extreme environmental challenges at the historic Vyrnwy Dam in Wales, where the team restored critical safety monitoring systems compromised by harsh conditions.
Key Information
Project name: Vyrnwy Dam Monitoring
Client: Confidential
Location: Wales
Date: 2025
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Project Summary
SOCOTEC's Monitoring team developed and implemented innovative, cost-effective solutions to restore critical safety monitoring capabilities at Vyrnwy Dam. The team successfully overcame extreme environmental challenges, including ochre build-up that had compromised existing systems, delivering bespoke monitoring technology that ensured the dam operator could meet legal safety obligations.
Project Details
The 140-year-old Vyrnwy Dam, Britain's first gravity dam built from mass-cut stone, faced unique monitoring challenges with two critical systems, which comprised:
- A pendulum monitoring device measuring dam displacement failing due to ochre blocking optical sensors
- The uplift pressure drain monitoring system was non-functional due to ochre-blocked pipework
Additionally, monitoring over 80 uplift pressure well flows in the dam's narrow, wet, and difficult-to-access adit presented significant challenges:
- Confined space requiring specialist equipment and rescue teams
- A 200m tunnel with slippery conditions and ochre deposits
- Rapid deterioration of equipment when exposed to air
- Failure of optical-based monitoring technology in these conditions
The SOCOTEC Monitoring team developed multiple innovative solutions:
1. Custom Pendulum Monitoring System
- Developed a novel wire position monitoring system using 4-20mA ultrasonic distance sensors
- Eliminated vulnerability to ochre by avoiding optical components
- Created a smaller, easier-to-protect solution
- Achieved comparable accuracy to commercial devices at significant cost savings
2. Comprehensive Drainage Monitoring Solution
- Engineered an elegant solution instead of installing 80+ individual monitors
- Utilised an existing horizontal steel threshold as a weir plate
- Blocked a drain to force leakage water over the plate
- Installed a high-precision pressure sensor with ±0.5mm accuracy
- Connected to an existing analogue radio node
3. Wireless Data Transmission System
- Connected all instruments to radio nodes for wireless data transmission
- Relayed data to monitoring software for remote access
- Provided real-time insight into asset behaviour
- Eliminated manual reading requirements
Results
Despite physically demanding conditions, the team successfully completed the maintenance in a single day, demonstrating exceptional service and commitment.
The innovative solutions went on to fully restore critical safety monitoring capabilities, while achieving 100% functionality across all monitoring systems. SOCOTEC delivered cost-effective alternatives to traditional approaches and enhanced the dam operator's ability to meet legal safety obligations.
"We built an experimental model with two sensors monitoring the X and Y movement axes, refined it in the workshop to test its abilities and then installed it in another of our client's dams, Clywedog, where an established commercial automated pendulum device from China had been monitoring. We then compare side by side to ensure our device matched the established device's readings – which it did.
Our device doesn't use optics, it is much smaller to house and therefore easier to protect against the ochre problem. A further benefit is that it is much cheaper to build than the commercial devices available from other suppliers. We therefore decided to remove it from its trial at Clywedog and install it in the adit at Vyrnwy Dam."
