Fort Augustus Lock Gate Replacement and Kytra Embankment upgrades

Fort Augustus Lock Gate Replacement and Kytra Embankment upgrades
Location: Fort Augustus, Scottish Highlands
Timeframe: November 2019 to March 2020
Team experience at Mackenzie: 16 years

Key project features:
Working in close proximity to local community and extensive key stakeholder communication and liaison
Supplier and key sub-contractor management and co-ordination
Environmental protection while working within the canal network
Installation of sheet piling within the canal network

Fort Augustus is a key part of the waterway between Loch Oich and Loch Ness, which includes Lock structures at Cullochy, Kytra and Fort Augustus. Following the successful completion of Phase 1 of the Fort Augustus Gate Replacement in the spring of 2019 – a recipient of the Scottish Civil Engineering Award for Heritage and Restoration for 2019 – Mackenzie Construction was appointed as main contractor to undertake the next phase of this important infrastructure project.

The challenge
This phase of the project consists of the replacement of lock gates 1, 3, 4, 5 & 6 on the Fort Augustus lock flight. Due to Loch Ness water Levels we required to install Gate 1 in the wet and control the flight for the install of Gates 3,4,5 & 6. Gate 6 was then managed with upstream equipment to control the lock flight. To allow this work to be completed, the lock flight was drained, and scaffolding built to allow access to the gates. Scottish Canals managed the work of safely draining the locks and Mackenzie Construction was then responsible for maintaining the level of the water in the locks during that period by installing a temporary dam and pumping equipment upstream.

The solution
Gate 1 & 3 were installed using dive teams underwater. The team deployed the client-supplied stop-planks and pumping equipment for the duration of the lock flight, and new pintels were installed at each of the other gate locations. Additionally, Mackenzie Construction was responsible for the cranage for the works. A further section of this works comprised two embankment and tow path repairs between the Kytra and Cullochy lock gates. The repairs consisted of the installation of sheet pile line, placement of 6A stone to re shape and strengthen the existing bank profile, and then the successful re-installation of tow path.

To enable this project to proceed, temporary works were also required:
1. Installation of two turning heads on the towpath, one at each embankment failure CC2&4 to facilitate material delivery
2. Embankment strengthening at CC1 to enable construction vehicles to pass
3. Installation of two rock berms onto the existing towpath, one at each embankment failure CC2&4 to both strengthen the bank and provide platform for pilling.