The Upper Yarra dam wall, constructed of earth and rock fill, was the highest dam of its type in the southern hemisphere when completed in 1957, and one of the first of Melbourne Water's dams to be constructed without a concrete corewall.

The reservoir and its associated works, was also the most expensive water supply project the MMBW had undertaken, and took ten years to complete.

The completion of the dam in 1957 coincided with the centenary of Melbourne's water supply system, beginning with the building of the Yan Yean Reservoir in 1857.

The Mt Little Joe tunnel (6,200 ft) and the Upper Yarra diversion tunnel (2600 ft) together represented a major piece of engineering.

The extensive borrow pit graphically illustrates the enormous amounts of earthfill excavated locally and used for the construction of the dam wall.

The flying fox structure and gauging weir on the Yarra River below the diversion tunnel are features of interest relating to the impact of the reservoir on the natural water course of the Yarra River.

The reservoir and associated park are valued by the community as a popular place for picnics and sightseeing, with spectacular views of the surrounding forested catchment, extensive stretch of water and landscaped park visible from the visitor's viewing platform. (McCann 1993: 171)

The Upper Yarra dam is rolled earthfill and rockfill embankment 90 meters above the river bed at the highest point and 610 meters along the crest. The reservoir has a capacity of 200,000 megalitres. (Supple 1991)

It is filled by water from the surrounding forested catchment, and also receives water diverted from an underground connecting tunnel from the Thomson Reservoir. Water travels via pipelines and aqueducts to Silvan Reservoir and from there to Melbourne. Associated structures of the dam include the original diversion tunnel, spillway and four outlet towers, an outlet tunnel linked to the Upper Yarra-Silvan conduit (completed in 1948), and a new thigh level outlet through the right abutment of the dam..

On the reservoir wall is a viewing platform, with a sandstone structure bearing a brass plaque on each face. The plaques give details of the dam's construction and Commissioners at the time of the opening by the Governor of Victoria, General Sir Dallas Brooks on 26 November, 1957, together with a tribute to the workers:

"A tribute to the initiative, industry and skill of the men of many occupations who combined in the building of this great work for the lasting benefit of the metropolis of Melbourne."

Another plaque commemorates the centenary of Melbourne's water supply system (Yan Yean Reservoir, 1857). Nearby there is also a eucalypt tree planted by the Governor of Victoria, Sir Rohan Delacombe, on 19 October 1966.

A gauging weir and flying fox is located on the Yarra River below the diversion tunnel outlet. The station is now computerised, but the flying fox structure is still located on the site.

Structures associated with the Upper Yarra Aqueduct include a caretaker's hut of vertical weatherboard construction typical of the reservoir construction buildings. It is located adjacent to the point at which the open channel enters the Little Yankee Jim Creek siphon. Apart from siphons to cross valleys, the aqueduct is an open channel until it reaches OO Basin where it enters the conduit pipeline. The water flows for 14.5 km until it reaches Mt Little Joe tunnel, near Warburton, then 22.5 km to Silvan Reservoir.

The Borrow pit is an extensive area from which the red clay earth was excavated to construct the earth and rock fill dam wall. Much of the area has regenerated, with a few sections of exposed cliff face, while the water collecting in depressions now attracts wildlife. (McCann 1993: 171-72)

A replica of a waterwheel stands in the park grounds below the dam. It was made by the Board of Works with original work and gears from the waterwheel that served the Connection Mine and later provided to McVeigh's Upper Yarra Hotel. It is separately listed on this database.

Physical Conditions: Excellent

Integrity: Minor Modifications