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DAM SPILLWAY DAM SPILLWAY

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					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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posted:8/21/2011
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