2009 – Design of Tinaroo Falls Dam Spillway Capacity Upgrade

John Richardson

In 2003, the Bureau of Meteorology revised the Probable Maximum Precipitation estimates and rainfall temporal patterns for Tinaroo Falls Dam using the Revised Generalised Tropical Storm Method. Based on the revised floods, the dam was assessed as having an ‘Extreme’ Flood Hazard Category rating. Subsequently a comprehensive risk assessment was undertaken in 2008 and this assessment recommended the dam be upgraded to pass the Fallback AFC which is the PMF event. The current spillway has a capacity for a flood with an AEP of 1 in 200. To achieve the AFC the concrete gravity Main Dam requires stabilising with post-tensioned anchors. The crest of the homogenous Saddle Dam needs to be raised by 300 mm and a filter and weighting zone needs to placed on the downstream face

Keywords: Tinaroo Falls Dam, mass concrete gravity dam, post-stressed anchors, Barron River, filter, weighting zone