Construction impacts Construction of the spillway capacity upgrade will not disrupt current water supply to SunWater customers. BJELKE-PETERSEN Access to the Yallakool Tourist Park and boat ramp will not be affected. However, during construction, DAM SPILLWAY access to the picnic area and second boat ramp CAPACITY UPGRADE PROGRAM will be restricted between June and late September for safety reasons. SunWater understands that the local tourist park is a popular area for visitors and will endeavour to minimise noise disruption during the upgrade works. Your patience during this construction period is appreciated. How much will this upgrade cost? Fred Haigh Dam was raised by constructing a 2 metre To bring the dam's spillway in line with national high concrete wall along the length of the dam. spillway capacity guidelines, the first stage of the Further information upgrade is estimated to cost $5.7M. Upgrade features Further information about SunWater's The upgrade will be fully state government funded. Spillway Capacity Upgrade Program It is important to note that the upgrade will not increase the water storage capacity of the dam. is available on our website: Why must the spillway be upgraded now? This will remain at current levels. www.sunwater.com.au In this current period of drought, it's difficult to The first stage of the upgrade to the Bjelke- Alternatively, you can phone imagine rainfall of this nature, however, as Petersen Dam spillway will involve raising the top SunWater on (07) 4132 6200. weather patterns can range from one extreme of the saddle dam and main dam by 1.2 metres to to another, it's important that we take action now prevent excess water from spilling over the dam based on this new data. If the spillway does not wall during extreme rainfall. This additional height have this capability to pass excess water in a safe will allow the dam to hold excess water until it can manner, extreme floodwaters could cause a failure pass safely through the spillway. The length of the of the dam wall. saddle dam wall will also be extended. It would be remiss of SunWater as a responsible dam owner not to proactively take steps to ensure 1.2 metres our water infrastructure can withstand any Based on last year's upgrade at Fred Haigh Dam, the spillway extreme weather conditions. upgrade will have minimal effect upon the dam’s appearance. Spillway upgrade construction at Fred Haigh Dam, Gin Gin– the first of the SunWater dams to be upgraded. SunWater, the owner and operator of Why must Bjelke-Petersen Dam undergo Bjelke-Petersen Dam, is undertaking a a spillway upgrade? spillway capacity upgrade in 2007 to The upgrade program has been prompted by the ensure that this dam can safely cope with Bureau of Meteorology's review of rainfall data extreme rainfall events. This upgrade has been fully funded by state government and Bjelke-Petersen Dam Spillway Capacity Upgrade over the past 100 years. New projections show a much larger extreme rainfall event may be possible forms part of SunWater's ongoing spillway February to November 2007 than was previously believed. The Bureau has indicated that this risk is very low being a “one in upgrade program. 100,000” chance of occurring in any one year. By comparison, the infamous Brisbane 1974 flood WORKS AREA SADDLE DAM BOAT RAMP AND was a “one in 80” chance event. Construction on the main Road will be closed YALLAKOOL Such an event has a relatively low statistical chance dam and saddle dam will during construction TOURIST PARK of occurring. However with our current weather occur from February to from June until late patterns experiencing cycles of extremes - both Access will not November 2007. September 2007. flood and drought - SunWater, as a responsible dam be affected. owner, is taking action to ensure its dams can safely and efficiently manage extreme rainfall events. Following the release of the new Bureau projections, SunWater prioritised which dams require spillway upgrades based on the national spillway capacity guidelines. These standards rate the dam in terms of: ■ Existing spillway's capability to safely TO MURGON - manage an extreme rainfall event BARAMBAH ROAD ■ Affected populations SADDLE DAM to be extended ■ Impact to ongoing water supply in an extreme event ■ Economic impact of the dam's failure While the spillway is extremely safe under normal SADDLE DAM conditions, Bjelke-Petersen Dam has been to be raised identified as the second dam to have its spillway by 1.2 metres WORKS AREA capacity upgraded to better manage the flows of an extreme rainfall event and ensure that excess SPILLWAY water can pass through the spillway safely. MAIN DAM to be raised by 1.2 metres When will this be happening? BOAT RAMP BOAT RAMP Construction for the first stage of the Bjelke- Petersen Dam spillway upgrade will commence in early February 2007. Construction of stage one of What is a spillway? YALLAKOOL the upgrade is expected to take around nine months TOURIST PARK to complete. A spillway is a purpose-built opening in a dam wall that allows the safe release of water downstream The first stage will vastly improve the spillway's once the dam is full. It is designed to direct water We appreciate your patience during this construction period capability to manage an extreme rainfall event. over the spillway rather than have it spill out over A second stage upgrade will be undertaken in the dam wall. This ensures a safe and controlled the next five to twenty years, following completion release of water downstream via of spillway upgrade works to some of SunWater's a river or channel. other dams.
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