The Coliban system of waterworks

The scheme had its origins in a Parliamentary enquiry of 1862 into the practicability and cost of carrying water from the Coliban River to the new mining towns of Bendigo and Castlemaine. Tenders were called shortly afterwards and the first reservoir was completed in 1870. This was formed by an earthen embankment 580 m long and 15 m high.

By 1903, the works comprised two principal reservoirs with a combined capacity of 32,700 ML, 25 subsidiary storages, 580 km of channels, 490 km of pipelines and some tunnels, supplying water to several towns with a combined population of 64,000 and providing for irrigation, mining and industry.

The early accidents included substantial damage to the first reservoir shortly after completion, following a flood of unexpected magnitude, and compounded by inadequate geological investigation of the site, damage from flood debris to the 2.4 m diameter outlet valve, and the collapse of the 2.4 m diameter cast iron pipeline carrying the main supply from the system by inverted siphon across a deep valley.

Ingenious remedial works overcame these and other massive problems and it was possible for the Chief Engineer of Water Supply to say in 1919 that:

the works of the Coliban System . . . have, without the adoption of heroic measures and at a cost not immoderate, been placed in an excellent condition of maintenance, improved and extended, and rendered capable of such further extension that they will, with proper upkeep and management, render efficient service to the public for many generations to come.

Today, after many modifications and extensions, and further remedial measures, the Coliban System serves a population of more than 64,000 and 400 ha of irrigation (Fig. 3). The early engineers' skills, initiative and faith have been vindicated.

3 Coliban Water Supply System, Victoria

Australian Academy of Technological Sciences and Engineering