North Coast - Northern Rivers Region Clarrie Hall Dam Raising Concept Design
Clarrie Hall Dam is a major water source for part of the north coast of NSW including the Tweed Shire and is located on Doon Doon Creek, some 15 kilometres south-west of Murwillumbah. It is a prescribed dam under the Dam Safety Act (NSW) and has been assigned a HIGH A Consequence Category in accordance with NSW Dams Safety Committee guidelines.
The dam consists of a concrete faced rockfill embankment, a concrete lined spillway, intake and outlet works and was designed by Public Works Advisory (PWA), construction was completed in 1984. Following on, spillway upgrade works were designed by PWA with construction completion in 2014. During the upgrade works, several challenges emerged including high public exposure resulting from the location of the project, limited daylight work hours and complexities related to the procurement of suitably sized replacement stones.
PWA has recently undertaken concept design for raising the full supply level of Clarrie Hall Dam by 8m, to increase the storage capacity from the current 16,000ML to 43,000ML. Hydrological, seismic, geotechnical and environmental studies were carried out as part of these works. Results from these studies were incorporated in an overall Concept Design Report which included drawings, cost estimates, risk assessment and constructability issues. The project work satisfied the requirements and expectations of PWA's client, NSW Dams Safety Committee.