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Burrinjuck Dam, situated high in the mountains
of the Great Dividing Range, is near the
headwaters of the Murrumbidgee River 60km from
Yass.
The name
Burrinjuck comes from the Aboriginal words
“Booren Yiack”, meaning precipitous mountain.
The dam is appropriately named as it lies
between the Barren Jack and Black Andrew
Mountains.
Burrinjuck Dam was the first major dam built for
irrigation in New South Wales to supply water to
the Murrumbidgee Irrigation Area. Building
commenced in 1906 and the first water was used
in 1912. When the original dam was completed in
1927 it was ranked as one of the world’s
greatest.
Early
Days
In 1891,
the drought-ravaged Murrumbidgee Valley was
nominated as an ideal location for irrigation
development. After devastating droughts in 1901
and 1902 State Parliament approved the
establishment of the Murrumbidgee Irrigation
Scheme. Burrinjuck Dam was constructed to
provide water for the scheme.
 Construction started in 1907, but due to delays
caused by the shortage of labour and materials
during World War 1, the original design was not
completed until 20 years later, although it was
able to provide water for irrigation in 1912.
With the
dam largely completed, a massive flood in the
Murrumbidgee Valley in 1925 sent water more than
a metre deep pouring over the crest of the main
wall. Although Burrinjuck was barely damaged by
the torrent, the size of the spillways was
increased and the height of the main wall raised
to prevent future devastation.
Work on
these alterations and other improvements began
in the 1930’s. Again, construction was delayed
by a world war but finally, Burrinjuck Dam was
completed in 1956. It was the first major dam
built for irrigation in NSW and when
construction began in 1907, it was the fourth
largest dam in the world.
The
Structure
Burrinjuck is a ‘mass gravity dam’. This type of
dam holds back stored water by using its own
weight to withstand the pressure from the water.
The basic structure of the dam wall is similar
to a gigantic brick wall. It is made of massive
concrete blocks, which were cast in situ and
contains huge granite boulders.
 Following an analysis of the largest possible
flood that could occur, the spillway capacity of
Burrinjuck Dam was re-evaluated and the
spillways were upgraded and enlarged. One
hundred and fifty steel cables were inserted
into the structure at bedrock level (at maximum
length of 130 metres) and each cable was post
tensioned to 1,100 tonnes each.
Work has
since been carried out, in 1994, to raise the
wall a further 13.4 metres and bolt the wall
down into its foundations, by two rows of
post-tensioned steel cables. In 2001, further
work took place, to equip the dam to handle the
largest possible flood - one that would be
expected to occur, on average, only once in
100,000 years.
The area
of stored water is 5,600 hectares. The catchment
area is 12,900 square kilometres and the
shoreline is 645 kilometres. Burrinjuck is one
of the first dams in NSW to have environmental
flow releases based on inflows.
It is a
water sports playground and fisherman's
paradise. Facilities include a picnic area and
free electric barbeques. |
