GETTING THE WATER TO MELBOURNE
The
Aqueduct
A Dam is of little use if its output is not delivered to its destination!
Apart from siphons to cross valleys, the Upper Yarra Aqueduct is an open channel
until it reaches AW Basin where it enters the conduit pipeline system. The water flows for 14.5 km until it reaches Mt Little
Joe tunnel, near Warburton, then 22.5 km to Silvan Reservoir.
Upper
Valley Conduits
These are vitally important assets in the Melbourne Water supply system,
enabling the transfer of water from the Upper Yarra reservoir into the Melbourne metropolitan supply system.
It is predominately a dual pipeline system, comprising the Yarra
Silvan Conduit and the Yarra Valley Conduit
Yarra Silvan Conduit (YSC)
The
YSC connects the Upper Yarra Aqueduct to Silvan Reservoir. From the aqueduct two penstocks control the flow into each of the
YSC mains. At Mt Little Joe, the two mains spill into a holding basin and flow into a single buried tunnel
called Mt Little Joe Tunnel. Flow into this holding basin is controlled by two penstocks, one for each
main. At the end of the tunnel the flow spills into a second holding basin.
From the holding basin,
flow is returned to a dual pipe system through to Silvan Reservoir. The YSC also takes water from two
tributaries, as well as the O’Shannassy reservoir. When the YSC is used to provide water supplies
to the Upper Yarra townships, these water sources must be turned out, due to variability in water quality.
Yarra Valley Conduit (YVC)
The typical
operating strategy for the YVC is for flows to fluctuate throughout the year in response to required storage levels in downstream
storage reservoirs (Silvan, Cardinia).
The YVC and YSC all supply water from the Upper Yarra reservoir to Silvan reservoir.
Along the way, unfiltered water is supplied to Warburton, Warburton East, Yarra Junction and Woori Yallock townships in the
Upper Yarra Valley.
Water to the YSC first travels along the
Yarra Silvan aqueduct for 11.4 km, whilst the YVC is an enclosed pipeline for its entire length.
The YVC and YSC travel
parallel to each other between Brahams and Lyrebird treatment plants and then separate. The YVC then travels north of Warburton
and Yarra Junction, supplying water to the Martyr Rd and Yarra Junction treatment plants, whilst the YSC passes to the south
of these towns.
The two mains cross over downstream of Yarra Junction, with the YSC running alongside the Lusatia Park
Treatment plant and terminating at the northern end of the
Silvan reservoir. The YVC inlet to Silvan is at the southern end of the reservoir.
Readers
are invited to refer to these Engineering papers for detailed information about the Upper Yarra Conduits.
The author 's Photo Album (2012) provides additional information about the Conduits.
