288 x 240 mm. A view looking down on to the dam from below the reservoir, with the spillway visible beyond the dam. The Cataract Dam is situated a little below the junction of Cataract Creek and Cataract River. The building of the dam, which forms part of Sydney's water supply system, came as a result of the Sydney drought of 1901-2, the first of any severity since the formation of the Water Board in 1888. Work on the dam started in 1903 and the dam, built of sandstone, was largely completed by 1907. The reservoir was filled to capacity for the first time in 1911 (as seen here), and it was decided to build a spillway, which work was completed in 1915.