Date 01 Sep 2022
The ESD Joint Venture has reached a significant milestone at Loch Ness with the new water treatment plant and distribution network coming into operation.
Since the project began in 2018, it has stretched the problem-solving abilities of its engineers, innovated UK-firsts, crossed international teams, and garnered several industry awards for the solutions forged during its construction.
The four-year project, one of the biggest drinking water investments made by Scottish Water in recent years, involved some unique engineering challenges, including the creation of a new intake system from Loch Ness and a distribution system to connect two previously separate water supply areas. This included the creation of two service reservoirs – one on high ground north of Fort Augustus; and one which re-uses part of Invermoriston’s previous Water Treatment Works to provide improved resilience to the area.
A core challenge was that the route of the connecting pipework had to follow a 10km section of the famous Great Glen Way. Within Fort Augustus, a new water main crossing also had to be achieved beneath the River Oich and the 200-year-old Caledonian Canal, one of the Highlands most popular visitor attractions and a Scheduled Ancient Monument. This work had to navigate unique topography and ground conditions, both natural and man-made, while safeguarding both the structure of the Canal and the local environment.
The new intake system required the installation of a 75m pipeline on the floor of Loch Ness, Scotland’s (and the UK’s) largest freshwater loch, within the dramatic landscape and distinctive ecology created by the Great Glen Fault. To avoid using concrete, mesh bags filled with rocks were used as the main structure to secure the water intake. Disruption to the loch was further minimised by assembling the pipes on land and then floating them into place using a ballast and concrete collars for positioning.
To install the 350 metres of distribution pipes that would run under the River Oich and the Caledonian Canal, the team deployed an innovative solution utilising a pioneering hammer-driven auger bore technology sourced locally from Finnish company Geonex, the first time this approach had been used on a Scottish engineering project.
Working to restricted windows around the tourist season and salmon migration cycle, the team utilised off-site assembly to ensure operational efficiencies, meaning only 15% of the total project hours were spent on site, greatly improving the cost, health, safety and carbon performance of the project.
Wendy Cooper, Chief Operating Officer, ESD, commented: “The Loch Ness project has encountered many challenges along the way, but the team has managed to achieve excellence in delivery – and in a way that is sustainable and sensitive to the outstanding natural landscape and the local communities. This is all down to the combined efforts of the Scottish Water team, ESD, key supplier RSE, and local supply chain companies, including many from the Highland region.”
Mark Dickson, Director of Capital Investment, Scottish Water, added: “A mix of new technologies, digital approaches and ingenuity have driven this project and enabled it to overcome some significant challenges. By working closely with the Highland Council, local businesses and communities, we hope that we have left a positive legacy, both in terms of what has been built and the way it has been achieved. Most importantly, we have enabled customers to be supplied with clear, fresh and great-tasting drinking water on a sustainable basis for decades to come.”