(Prepared by W R Darby at the request of the South Belfast Historical Society)
With a continuing increase in population and demand from the increased economic activity, the Belfast Water Act 1840 was passed and the newly constituted Commissioners became responsible for supply to a population at that time of over 70,000.
In spite of the
vigorous programme of works and the bringing into service of more streams and
springs in and around the town, by 1852 there was a shortfall of almost one
million gallons per day with the position worsening as the population and
activity continued to grow at an unprecedented rate. There followed a series of Parliamentary Acts
(1865, 1874, 1879 and 1889), which expanded the system to include reservoirs as
far out as Woodburn (above Carrickfergus) as well as increased storage within
granting of the
By 1891 the further increase in population led to the appointment of Mr Luke Livingstone Macassey MICE to survey and report on the available sources. This resulted in the decision to proceed with the Mourne scheme as he had recommended and statutory powers were obtained under the Belfast Water Act of 1893.
It is interesting to note that Lough Neagh, which is now such an important water source for the entire area, was at that time considered to be “entirely unsuitable” and impossible of being rendered suitable for town supply by ordinary sand filtration. That view was reported by Macassey from an analysis carried out by Mr Robert Barklie FCS.
declared the Mourne catchment as “beyond suspicion” and “the water soft and
pure and possesses a bright appearance”.
Another bonus was that the Mourne scheme could proceed by instalments so
that the supply could be piped to
were constructed on the Kilkeel and Annalong rivers together with a conduit,
pipeline and tunnels to take the water to a new open service reservoir at
Knockbracken capable of storing 100 million gallons. Macassey had estimated correctly that the
Mourne scheme would be capable of supplying
By 1910 it had
become apparent that the increase in demand called for Stage 2, which was the
construction of the
Construction of the reservoir embankment proved very difficult and stretched the technology of the time to the limit. Earlier test borings had suggested bedrock at 50 feet, but this proved only to be large boulders in a glacial moraine and bedrock was some 150 feet or more below the valley floor. This greater depth in water-saturated ground could only be worked in by the use of cast iron shafts with men working in compressed air compartments to keep out the watery silt. The “cut-off “ trench required to seal the dam wall was excavated down 32 feet into the solid rock to finish some 212 feet below the original river bed, with that phase being completed in 1929 after six frustrating years. Completion of the reservoir was now straightforward and the water first reached designed top water level in September 1932. It is reported that there were eight fatalities during the construction, which took ten years rather than the six originally contracted. The reservoir was finally completed at a reported cost of £1,350,000 and was officially opened on 24th May 1933 by the Duke of Abercorn, Governor of Northern Ireland.
So, with a
storage capacity of 3,000 million gallons at the
For stage 3 the
original Macassey plan to build a second reservoir in the Annalong valley was
abandoned and a two and a half mile tunnel was constructed in the period 1950
to 1952 under Slieve Bignian. This
allowed the bulk of the flow in the Annalong river to be routed into the
predicted the Mourne works would provide for
Mention must also be made of the construction of the famous Mourne Wall which surrounds and protects the catchment area. Construction of this 22 mile long wall began in 1904 and took 18 years to complete. It provided work for many in the area with construction being carried out in the early Spring to late Autumn throughout that period. It is truly a wonderful piece of work and is a very useful navigational aid for people enjoying the Mournes, particularly when the mist descends.
William R Darby
2 November 2010.