The Construction of Ballure Reservoir
Until the establishment of the Isle of Man Water Board in 1948, Ramsey's public water supply was provided by a private company, the Ramsey Water Works Company Limited, established by Act of Tynwald in 1859.
In its early years the Company built two concrete walled reservoirs designed to capture and store water flowing down the Ballure stream. The original lower reservoir, now disused, can still be seen alongside the access road and just downstream of the present Water Treatment Works. The original upper reservoir also still exists, but was roofed over and converted into a treated water storage reservoir at the time of construction of the Water Treatment Works in the 1950's.
By the late 1870's the Water Works Company, finding the storage they had available insufficient to maintain supplies to the town during the summer visiting seasons, decided to promote the construction of a new dam across the valley just upstream of their two existing reservoirs, forming a new reservoir holding about 18 million gallons.
Construction of the new dam commenced in the summer of 1881. The work was carried out under the supervision of an Isle of Man based civil engineer Mr Frederick Saunderson, from designs prepared by the consulting engineers Bateman, Hill and Bateman, one of the leading dam engineers in England at that time. Construction was completed in December 1884.
The dam is an earth embankment dam of typical design for the period. The base of the valley beneath the dam site is filled with deep deposits of glacial drift material overlying the bed rock. In order to limit the loss of water from the reservoir beneath the dam, a cut off trench was excavated across the valley down to underlying rock and refilled with clay puddle. The record drawings show that in the base of the valley the cut off trench was up to 17 metres deep; its excavation and support must have represented a considerable feat of engineering for its day.
The dam itself, which has a maximum height of about 17 metres, was constructed using earth fill material excavated from the valley upstream of the dam site. The dam was sealed by extending the clay filled cut-off upwards to the dam crest with a central puddle clay core.
A masonry bye-wash channel was constructed around the west side of the reservoir, which intercepted the incoming streams and allowed these to be turned away from the reservoir when water quality became poor due to heavy rain. An overflow weir was provided discharging into the bye-wash channel immediately upstream of the dam crest.
A single draw-off pipe 18 inches in diameter was provided beneath the dam. Two upstream draw-off valves were provided to control flows out of the reservoir into the draw-off pipe, a lower valve at the bottom of the reservoir to allow it to be emptied, and an upper valve on an inclined pipe laid up the west side of the reservoir basin for normal draw-off. Both valves are operated from a head stock connected to the draw-off valves by inclined spindles.
The Water Works Company kept meticulous records of the operation of their reservoir, from the time of first filling it right up to its dissolution in 1948. The Reservoir Record book still survives in the Water Authority's archives. The Book records that the reservoir was first filled with water in January 1885, but that the upper portion of the embankment for about two or three feet was found to be leaking. In 1888 the clay puddle in the embankment was raised nearly to the level of crest and this cured the leakage.
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