When early in 1893 two severe floods devastated Brisbane, Australia, its citizens demanded flood prevention. This article explores the responses to these floods as engineers sought measures to control the river with technology. I argue that local factors of drought, economics and politics delayed a decision for 40 years. It was not until the 1930s Depression, when the State sought unemployment relief projects and the expanding urban settlement demanded water supply that the benefits finally outweighed the cost of dam construction. In 1935 the government finally sanctioned building Somerset Dam, the first Australian dam to combine water supply and flood mitigation. This article has been peer reviewed.