Projects
Temporary Water Control for
Live Aeration Ditch Works, Cornwall
Galiford Try required the installation of two new submersible mixers within a live aeration ditch at Luxulyan Sewage Treatment Works.
Normally, this type of work would require the ditch to be drained. However, with no spare treatment capacity on site and a live biological process that could not be interrupted, the installation had to be completed while the aeration ditch remained fully operational.
The project required a specialist temporary water control solution capable of creating a dry working area around each mixer location without isolating flows or disrupting the treatment process.
High Water designed and installed a bespoke split Modular Limpet Dam to create a localised dry working area around each mixer position.
Rather than attempting to isolate the entire process, our engineers developed a compact cylindrical cofferdam that enclosed each installation point while allowing the surrounding aeration ditch to remain in service.
The geometry of the Limpet Dam balanced hydraulic loads across the structure, enabling a lightweight design that could be lifted safely within the site's restricted working area. Sequencing models were produced to demonstrate the installation methodology before working alongside Hewson Consulting Engineers to finalise the design. The system was then fabricated in modular sections before being assembled and installed by our specialist site team under confined space procedures.
Once sealed and dewatered, the dry working area allowed Galiford Try to install the new submersible mixers safely and efficiently, without interrupting the live biological process.
Once the reservoir had been dewatered, the failed liner and redundant infrastructure were removed. Our team then reshaped and reinstated sections of the reservoir bunds where required, restoring the design profile ahead of installation of a protective geotextile layer and replacement liner system. Environmental considerations were incorporated throughout the works. Turf from the anchor trench was carefully lifted, stored and reinstated following installation of the new liner, helping preserve the surrounding grassland and minimise disturbance to the site.
The bespoke Limpet Dam enabled critical upgrade works to be completed without draining the aeration ditch or interrupting wastewater treatment operations, avoiding costly process disruption and maintaining operational continuity throughout the project.
By creating a localised dry working area, the solution eliminated the need for divers while providing safe access for installation works. The modular design also allowed rapid installation and removal, helping minimise programme duration and demonstrating the value of bespoke temporary water control for live operational assets.
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Whether you need a temporary dam, specialist access solution or end-to-end engineering support, contact HighWater for a free consultation.