Connection key to overall plan

In a remarkable feat of engineering in the hills north of Glasgow, contractors have completed an intricate system of interconnections to link up two of Scotland’s principal sources of fresh water, Loch Lomond and Loch Katrine. The completion of the Strathblane Cross Connection will, says Scottish Water (SW), save customers more than £500,000pa because pumping and hence energy requirements will be reduced.

Loch Lomond and Loch Katrine supplies, initially separated by a 30m vertical gap, have been linked so gravity flow is maintained from Loch Katrine to the existing Balmore WTW near Glasgow. The Strathblane scheme, the first element of the Katrine Water Project (see p19) to be constructed, was made possible by unprecedented co-operation between the former East of Scotland Water and West of Scotland Water authorities prior to their amalgamation into Scottish Water.

Professor Alan Alexander, chairman of Scottish Water, said the £2M scheme is the “perfect match” to the Loch Katrine system, which itself was an “engineering marvel devised 140 years ago by Glasgow Civic Fathers to

provide the city’s first unpolluted water supply”.

Praising the ingenuity of the modern water engineers’ work on the Strathblane project Professor Alexander said: “This is an example of the expertise of staff of all three former authorities used collectively for the benefit of a very large number of our customers.

“Moreover, it demonstrates how a single organisation can, with efficiency and purpose, take forward major water distribution plans in the pursuit of quality control and cost-effectiveness. The Strathblane Connection is an achievement that entirely compliments the great legacy of water assets that have been provided for the people of Glasgow and elsewhere. Clearly, the benefits to public health will be immediate and the savings will be substantial.”

Prior to the amalgamation of the Scottish water authorities into Scottish Water, two of the major supply schemes were operated separately, even though they were in close proximity. West of Scotland Water supplied the Milngavie treatment works by gravity flow from Loch Katrine and East of Scotland Water supplied Balmore WTW by pumping from Loch Lomond.

As part of the project to upgrade the quality of water from Loch Katrine, these systems have been linked, which will enable some of the spare capacity at Balmore to be used to treat water destined for the Glasgow area.

The purpose of the Strathblane Cross Connection project was to construct pipework to enable up to 360M l/d of raw water to be transferred from the Katrine aqueducts to the Lomond aqueducts. This will provide raw water to be treated at Balmore treatment works for use in parts of eastern Glasgow and cut costs by reducing the amount of raw water pumped from the Ross Priory Pumping Station at Loch Lomond to Balmore WTW. Construction of a pipeline between the

Balmore treatment works and the mains network to the east of Glasgow started in July 2002 and will be completed by September 2003.

The Katrine aqueducts, which have a capacity of 567M l/d, convey a gravity raw water supply from Loch Katrine to Milngavie WTW, providing 70% of Glasgow’s water supply. The Lomond aqueduct, with a capacity 286M l/d, conveys a pumped raw water supply from the loch to Strathblane, where it enters a tunnel and flows by gravity to Balmore WTW.

By utilising the spare 150M litres of capacity at Balmore WTW, the size of the

proposed treatment works at Milngavie can be significantly reduced in size – minimising the impact on the local environment and

generating savings in capital expenditure on the Katrine Water Project. By the interconnectivity of Loch Lomond and Loch Katrine, there will be increased security of supply from two of the largest water sources in

Scotland, into Greater Glasgow and Forth Valley supply zones.