The purified water can
then go into the regatta
lakes where 25,000 aquatic
plants have been planted
along with the introduction
of 65,000 Australian bass
(fish) as part of the creation
of a working ecosystem. “We
only use species indigenous
to the area,” says Kevin Flynn,
SIRC venue manager.
As the water in the lake is static,
two underwater aeration fans have
been built as well as an aeration line that runs
the full length of the warm-up and competition
lake. These fans are used to help plant growth
and prevent stratification of the water. But
despite these measures some challenges in
water quality, like algal bloom, still occur.
Algal bloom, which can cause the water to
become toxic, inhibits the use of the lakes for
sports which require contact with the water,
like swimming. The bloom can be caused by
stratification, where water temperature differs
through the layers. In February this year algal
bloom occurred, says Flynn, after a particularly
high rainfall. Watersports had to be cancelled
until the bacteria concentrations fell to
acceptable levels for primary contact water.
The high rainfall also meant that untreated water
went directly into the regatta lakes.
SIRC works with Penrith Lakes Development
Corporation (PLDC), in water management.
Matthew Zollinger is the manager for Land and
Water at Penrith Lakes. “We are trying to shift our
water quality basins into more of a macrophyte
(aquatic plant) dominated system instead of
an algae dominated system which will help
to reduce the occurrence of algae blooms. We
are looking at plants that can tolerate a large
variance in water levels and are investigating
using a floating raft system.” Zollinger says
reactive algae treatment is also being considered
like algal herbicides.
An ongoing study of freshwater mussels is being
monitored as these indigenous mussels have the
ability to filter water. Flynn says so far there have
been some good results.” They play a significant
role in filtering water, removing phytoplankton,
fine organic matter, bacteria and metal ions,”
says Flynn. “The filtration rate is believed to be
in the order of 20 mussels filtering 20 litres of
water in 24 hours.”
The finish tower and spectator
grandstand at the Sydney 2000
Olympic Regatta course.
Zollinger adds that there is currently work to
increase storage capacity upstream to reduce
the occurrences when water has to be released
directly into the regatta lakes.
Keeping the water clean is an ongoing exercise
and is key to the success of the site. SIRC receives
around 50,000 visitors per month and hosts trials
for the Australian National Rowing Team and
various regattas. So far the success has been high.