Eurobodalla Integrated Water Cycle Management Strategy

8.3.2 Immediate Measures
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Eurobodalla Integrated Water Cycle Management Strategy
The existing supply scheme has some inherent deficiencies. These deficiencies could be
easily overcome with appropriate immediate measures. Implementing the immediate
measures will greatly assist Council to recover from the current drought and improve the
system reliability. The deficiencies and the recommended immediate measures are
discussed below.
One of the problems Council regularly experiences after drought or after periods of being
solely reliant on the dam is the long period it takes to fill the Deep Creek Dam. Additionally,
Council is also reliant on Deep Creek Dam water to meet peak demands in the Batemans
Bay area, the reason for this being:
the small gravity transfer rate between Moruya Main Reservoir and the dam
the design and operational problems associated with the Malua Bay booster
pumping station, and
the inability of Moruya River pumps to run in parallel.
Hydraulic analysis (see appendix I) indicates that the transfer rate from Moruya main to
Batemans Bay could be increased by either relocating the existing Malua Bay booster
pumps and electrics to the disused Mossy Point booster pumping station, or by installing a
smaller pump within the existing Malua Bay booster pumping station.
Analysis shows that relocating the existing pumps and the electrical components is a more
viable option than installing a smaller pump. This is due to the better dual functionality (i.e.
relative ability to transfer more water in both directions by the same pump) achievable at
Mossy Point compared to Malua Bay. Upgrading the power supply to the Moruya River
pumps will enable parallel operation of the pumps and the ability to harvest more water.
The second issue currently faced by Council is the inability of the Tuross River system to
meet peak demands due to inherent river extraction problems, the flow mismatch between
the low and high head pumps, and the inadequate power supply to run pumps in parallel.
Council is currently implementing measures to overcome the river extraction problems.
Council should also consider eliminating the flow mismatch between the low and high head
pumps by either installing variable speed drives on existing pumps or by installing newer
pumps. The power supply upgrade to the Tuross River pump station should also be
expedited.
The third issue is the inability of the existing telemetry and the control elements on the
reservoirs and valves to operate in a narrow and more efficient range. Newer technologies
are now available to improve this situation. Therefore Council should consider undertaking
a review of the current operating concept with a view to improving efficiency and capacity.
The fourth issue is maintaining an appropriate chlorine residual throught the system. To
addess this requires the provision of rechlorination facilities at strategic locations.
8.3.3 Short term Measures
Short term measures include both the ability to harvest higher river flows and the ability to
transfer and store water quickly in Deep Creek Dam. This could be achieved by
implementing the following works.
A dedicated pipeline between Moruya River intake and Deep Creek Dam. It is
proposed to locate the pipeline along the existing high voltage transmission
easement. This will minimise environmental and social impacts during construction
and contain development within existing disturbed area. Economic analysis