75 Mile Dam, Warwick
The Southern and Western Railway opened in 1871 was the first railway system built in Queensland. Tin was discovered in Stanthorpe in 1872 and in 1873 and 1875-77 surveys were undertaken for the extension of the railway from Warwick to Stanthorpe.
Critical to the running of the steam locomotives on all railway systems was a reliable supply of water. This reliable supply of water was particularly critical in Australia due to the continent’s dry climate. In Queensland, difficulty of a reliable water supply was further complicated by 60 percent of the limited rainfall occurring during the wet season.
A site in the catchment of the Mineral Creek (but not on Mineral Creek) approximately 75 miles from Toowoomba was identified for the location of a dam to supply water to the railway system.
The dam was constructed in two stages. The first dam was constructed in 1879-1880 and was designed by Henry Charles Stanley (1840-1921) at the time the Chief Engineer for Railways, Southern Division, and later for the entire colony.
The dam was a concrete arch wall. The aggregate was won from the Gorge Railway Tunnel, constructed as part of the railway extension. The maximum dam height was 5.04 metres, and the crest was 24.5 metres long. The capacity of the dam was reported as both 1,295 cubic metres and 1,818 cubic metres. A pipe, by gravity, feeds a water tank located adjacent to the railway line down the range.
In 1900-1901 the dam was raised to 8 metres to 10 metres under Stanley’s supervision. The arch wall now has a crest length of 30 metres.
Prior to the construction of the 75 Mile Dam most dams constructed in Australia were earth embankments with a clay puddle core. Later different types of dams were constructed including buttress dams, multiple arch walls and thin arch dams. Most gravity dam designs were influenced by French masonry dams although in Australia they had concrete walls. The first arch dam was the Parramatta masonry arch dam completed in 1856 and the second, the first concrete arch dam, the 75 Mile Dam.
The 75 Mile Dam is a precursor to concrete dams built around Australia and was a pioneer in the use of concrete as a construction material. It is the world’s first concrete arch dam.
Engineering Heritage Recognition Program
| Marker Type | Engineering Heritage National Marker (EHNM) |
| Award Date | October 2021 |
| Heritage Significance | |
| Nomination Document | Not Available |
| Ceremony Booklet Ceremony Report |
Not Available |
| Plaque/Interpretation Panel Image | Not Available |
