Projects
Bespoke Limpet Dam Installation for
Live Water Treatment Upgrade, Somerset
As part of Bristol Water's investment in upgrading the Blagdon Water Recycling Centre, a new distribution chamber was constructed to connect the site's new treatment works into the existing oxidation ditch.
The project required two new pipe penetrations to be cored through the wall of the live process structure, presenting a significant challenge. The connection works needed to be completed without draining the oxidation ditch or disrupting the treatment process, whilst excavation behind the wall introduced additional structural considerations. Further investigation also revealed that the existing walls were constructed from blockwork rather than concrete, requiring a bespoke temporary works solution.
High Water designed and installed a bespoke Limpet Dam to create a dry working area around the proposed connection point.
The system isolated the section of wall where the new pipe penetrations were required without sealing against the ditch bed or interrupting process flows, allowing construction of the new distribution chamber to proceed safely.
Detailed engineering assessments considered hydraulic loading, sealing arrangements and the interaction between the temporary works and the existing structure. Particular attention was given to the temporary excavation behind the wall and its effect on structural stability during the works.
As the existing blockwork walls could not accommodate conventional fixings, our engineers developed a self-anchoring cantilever system using kentledge to apply the required loading and maintain a secure seal against the structure.
Once installed, the Limpet Dam provided an excellent seal with minimal pumping, even while the oxidation ditch remained in full operation, creating safe access for the coring works and chamber construction.
The bespoke Limpet Dam enabled the new connection works to be completed without draining the wider oxidation ditch or implementing extensive over-pumping, significantly reducing operational disruption.
Installation required just two short, two-hour stoppages, carefully timed to coincide with periods of low network flow, allowing the biological treatment process to remain operational throughout.
By creating a controlled, dewatered working area directly around the connection point, the system allowed excavation, coring and chamber construction to proceed safely while protecting the integrity of the existing process infrastructure.
The project demonstrates how specialist temporary water control and bespoke engineering can overcome complex structural constraints, enabling critical infrastructure upgrades to be delivered safely and efficiently.
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