Gold Creek dam and its unusual waste waterway (1890-1997): design, operation, and maintenance

Completed in 1885, the Gold Creek dam is an earthen dam located on the outskirts of Brisbane, Australia. The spillway system was refurbished three times, each time to increase the maximum overflow capacity. In 1890, a concrete stepped waterway was built to replace the damaged unlined-rock channel. This staircase chute is an unique structure: it is the first large man-made waste waterway built in Queensland, it is the only stepped weir built in Queensland before 1900, and it is, so far as the writers are aware, the first concrete-stepped spillway built for a large dam. The characteristics of the dam and its unusual stepped spillway are reviewed in a historical context. The design is compared with contemporary structures and present knowledge in stepped spillway design. The authors believe that the Queensland engineers gained expertise from overseas and within Australia for the stepped spillway design. However, the selection of concrete for the step construction was made by the local engineers and the reasons behind the decision are not yet understood.Key words: spillway design, engineering heritage, concrete construction, stepped weir, spillway operation, spillway refurbishment, 19th century structure.