Surveyor N.M Brazier named the Karalee Rock in 1894 while travelling to Coolgardie to lead a major survey of the country between Coolgardie and the Murchison.
The Karalee reservoir, rock catchment and aqueduct was a vital part of the development of the railway from Perth to Kalgoorlie. Water was constantly needed for the steam locomotives, construction work and employees.
This problem was solved by developing reservoirs at regular interval along the length of the railway. Karalee is the finest example remaining of these ingenious constructions.
The railway between Southern Cross and Coolgardie was constructed during 1895 and 1896. It passed three kilometres south of Karalee Rock.
The Karalee rock catchment and reservoir was constructed by railway entrepreneur, William Noah Hedges, in 1897.
Railway engineer William Shields designed the Karalee water supply to be adequate to service up to twelve trains a week running between Southern Cross and Coolgardie. Coolgardie grew so rapidly that within a year twenty trains were running between the two towns every day.
The water harvesting system ingeniously uses two huge granite outcrops. A stone dam wall was built around the perimeter of each rock and water flowing off the rock was caught by the wall, directing it into a stone-lined sluice that sent it to a large earthen reservoir before travelling cross county in a steel aqueduct and an earth channel. It is one of the miracles of this system that incredibly low annual rainfall (only 250mm per annum) resulted in substantial runoff – enough to fill Karalee with 48 million litres. The water collected in the dam was piped to an overhead tank 3.6 km to the south near the railway station. Karalee continued to supply water until the introduction of diesel locomotives in 1953.
In 1999 Karalee was handed over to the National Trust (WA). It was listed on the State’s Register of Heritage Places in 2001.