The construction of the Waitakere Dam in the early 1900s was another project that provided work for Swanson settlers. Many families, including the Peglers, Ashs, Taylors, and Foleys, were part of the huge labour force on this and other Waitakere watershed projects. The growing city of Auckland needed a reliable water supply and its council found a suitable site for a dam on the Waitakere Stream, rising high in the centre of the
ranges, flowing north and west to the Tasman Sea at Bethells Beach. There was a total catchment of 2100 acres. It was intercepted for water supply just above a fall of 330 feet at a point where the stream level is 615 feet above sea level.
In 1904 the Auckland City Council appointed H. Munro Wilson to oversee engineering and construction work, in association with waterworks engineer James Carlow. In June the Waitakere watershed was surveyed to acquire land.
Plans and specifications for the first stage of the Waitakere scheme were prepared in late 1904. A poll of city ratepayers in March 1905 approved the loan for waterworks extension. The majority of the 10,712 eligible ratepayers showed little interest — only 411 recorded a vote (300 for and 110 against). A large timber-impounding dam was designed to provide storage, until the main dam was completed.
A tramway was constructed to transport all materials and supplies, including the 28ft cast iron pipe lengths, from Swanson Station to the dam site.
A small steam-powered sawmill was established by T. W. Slater and Benner, a few hundred metres upstream from the main dam site. Timber was hauled by bullock team to the mill where it was processed into boards, scantling and sleepers for the tramway and the large timber dam. The timber was also used for fluming and boxing on the concrete dam, huts for the workmen and later, for the roofing of the break pressure tank and for the caretaker’s house.
In May 1907 Thomas Billington & Sons Ltd’s tender of £29,112 11s 6d was accepted to construct the concrete dam. Concreting the foundations began in 1908, extending to a depth of 37 feet. By March the 570,000 gallon break pressure tank was finished.
A major storm struck the Waitakere Ranges with disastrous results in May 1910. Torrential rain caused a large landslip in the reservoir of the wooden auxiliary dam. Trees and debris were washed downstream, building up against the dam. Water burst through the dam causing a gap of about 30 feet. Floodwaters swept down the valley and across the dam site, carrying timber, tools and plant over the 365 feet falls.
The concrete Waitakere Dam was completed by December 1910. Arthur Pegler was caretaker and foreman until he was succeeded by Fred Ash in 1924. Swanson settler John Taylor worked at the dam, followed by son-in-law Charles Foley. Swanson village storekeeper Foley’s two eldest boys, Jack and Bill checked the dam daily before a six to seven mile hike to school.
In 1926-1928 the dam was raised by 16 feet, doubling the storage capacity. The total lake area was 69 acres. Arthur Pegler’s cousin, George, a city council employee since 1912, worked on this project and afterwards continued to work in the Waitakere watershed area until he retired in 1953. In 1940-1942 a pipeline was laid from the filter station to Swanson and the North Shore.
Dawn Smith (nee Pegler), daughter of George, grew up in the area and was quite often up at the dam. In 1976 she and her family visited the Waitakere Dam and noted changes made by the Auckland Regional Authority. The bush track from the Scenic Drive to the dam was a tar-sealed road, public toilets had been built and the area was open to the public, who could leave their cars on Scenic Drive and walk to the dam. A house built from the timber of the original cookhouse had been demolished.
In 1991 the dam was emptied to strengthen the wall. People living downstream of the dam were afraid an earthquake could cause it to break. Downer & Co. Ltd installed hundreds of reinforcing rods and cables, pulling the two halves together, and anchored the whole structure to the ground. This work was finished in early 1993. The maximum capacity of the reservoir is 407 million gallons.
Rugged Determination, p67-72, p158