The impounded reservoir, also formed by Crotty Dam, is called Lake Burbury.

At 100% capacity the dam wall holds back 1,081,420 megalitres (38,190×10^6 cu ft) of water.

Both locations draw their names from the railway stopping place and the ghost town site of Darwin that was situated on the North Mount Lyell Railway between Gormanston and Kelly Basin.

It inundates the former Kelly Basin Road which was the subsequent name for the railway line formation.

In the 1910s the Mount Lyell Mining and Railway Company had investigated and surveyed a site very close to this dam for a proposed scheme.