Enlarged Cotter Dam Project
Date: November 2010
Cotter dam is the main water storage for Canberra, located approximately 30km west of the city.
This project was undertaken to increase the city’s water storage capacity after a couple of major droughts had Canberra on major water restrictions.
Enlarging the Cotter Dam involved building a new 80 metre high dam approximately 100 metres downstream of the existing Cotter Dam, as well as two substantial earth embankment dams adjacent to the main dam.
The new dam has a capacity of 76 gigalitres (GL), nearly 20 times its original size, and the new reservoir will increase the ACT Water storage capacity by 35%.
Rapid was engaged through a subcontractor on the project to supply and install a hydraulic system consisting of a power unit and Hydraulic cylinder to operate a temporary gate within the new wall construction to allow water overflow from the old wall upstream to pass through the new wall construction during construction, but then when no longer required to close this gate and then become redundant within the structure of the new wall.