Project: Birkenburn Reservoir
Scope: Pipe survey and decommissioning
We were commissioned by May Gurney working on behalf of The Canal and River Trust to survey a reservoir draw-off pipe that could not be de-watered; an earlier attempt to cofferdam around the inlet and de-water the pipe had resulted in catastrophic failure of the reservoir bed and the SEE has a zero water loss policy from the outlet.
We designed a launch-pod to enable a Pipe Inspection Vehicle (PIV) to be inserted in the live-pipe with no water loss and carried out the preliminary survey which confirmed that the pipe was in poor condition. The client then made the decision to decommission the pipe.
With no access to either end of the pipe, with no option to de-water it and with absolutely no-proprietary solutions available we set about inventing, designing and deploying a system that would get the job done.
The project was made all the more challenging by horizontal rain, followed by horizontal snow settling in 1.5m deep drifts and our amphibious ATV operating with its tracks permanently buried below the prevailing mud levels.
We designed, built and deployed a system that enabled us to fill a 90m long section of 600mm diameter live-pipe from the downstream end, with a structural grade concrete that would displace the water as it was pumped to ensure there was no washout and would start to harden in the extreme low-temperatures within a 4-hour window of opportunity.
We completed the pumping operation within the 4-hour window and the project was successfully completed on budget and two days ahead of programme. Samples of the mix reached a compressive strength of 53.2N/mm2 after 28 days and continued to harden.
Testimonial: They were recommended to us by the main contractor at a stage in the project when we had reached a stalemate and whilst they appeared confident in their capability to get things sorted, I remained unconvinced. However, they methodically set-about overcoming each problem with an innovative solution, nothing was too much trouble and they remained undaunted by endless challenges; not least of which was our Scottish weather.
Their solution to the pipe decommissioning problem was ground-breaking and executed like a military operation. I couldn’t praise them highly enough.
Alasdair Hamilton, Project Manager CRT