Blue Mountains Dams

Blue Mountains Dams

There are five dams in the Blue Mountains that are part of the water supply network - Greaves Creek and Lake Medlow dams, and the three Cascade dams at Katoomba. These five dams provide water for the Cascade water filtration plant, which supplies 49,000 residents in the middle and upper Blue Mountains. Woodford Creek Dam is no longer part of the Blue Mountains water supply.

How the Blue Mountains gets its water

Water in the Blue Mountains is delivered in a complex network of pipes that can source water from within and outside the Blue Mountains catchments - a small group of bushland valleys covering a combined 19 square kilometres.

The Cascade plant can be supplemented when needed with water from Oberon Dam or Duckmaloi Weir in the Fish River Scheme, west of the Great Dividing Range at Oberon.

Water from the Fish River Scheme can top up the Upper Cascades Dam, or go directly to Sydney Water's Cascade filtration plant. This gives WaterNSW and Sydney Water maximum flexibility to source the best quality water, as well as providing a supplementary water supply during periods of low rainfall or maintenance.

Residents in the lower mountains are supplied with water from Warragamba Dam, treated at the Orchard Hills water filtration plant, which also supplies the Penrith area. This water can also supply the middle Blue Mountains and some parts of the upper Blue Mountains.

Why the dams were built

Explorers Blaxland, Lawson and Wentworth reached present-day Hazelbrook on 20 May 1813, as part of their famous journey which was the first successful crossing of the Blue Mountains by Europeans. The following year, Governor Macquarie commissioned a cart road to the west and soon staging posts were built where permanent water was found.

The re-routing of the road and introduction of the rail link to Bathurst marked the end of the camps. Between 1867 and 1876 the railway was extended from Penrith to Bathurst. Steam locomotives need water, so the Department of Railways built several weirs and dams to supply steam trains as they crossed the mountains.

Construction of water supply dams followed. Some were re-purposed from railway supply dams, like Woodford Creek, and others like the Cascade dams and Lake Medlow, were purpose-built to supply local residents. Construction spanned many years from the first Medlow Dam in 1907, to Woodford Creek Dam in 1928, and Greaves Creek Dam in 1942.


Tuesday 18 January
2,497,329 ML
2,581,850 ML
9,342 ML
1,335 ML
-3,171 ML
Tuesday 18 January