2. Before….us
In its natural state, during severe droughts, the
Murray River became a chain of waterholes. The
river was too unreliable to enable intense
settlement.
Bend it to our will!
The Hume Dam completed in 1936 now ensures
a continuous flow of water. The massive
construction of regulation structures and water
storages of the last 100 years has made it
possible to develop the MDB irrigation industry.
3. • The Hume Dame is the main operating storage of
the Murray System. It takes a month for water
released from the Hume Dam to reach South
Australia.
• Water is diverted from the Murray River all year
round but demand is lower in winter. During
winter and spring, as much water is stored as
possible. Low inflows during summer mean more
water is released, mostly for irrigation but also
helps navigation and recreation on the river.
• 90% of all diversions are for IRRIGATION.
4.
5. Barrages, Weirs and Locks
• To prevent saltwater entering the system in the
lower lakes during times of low flow, 5 barrages
were constructed from Lake Alexandrina to the
Murray mouth.
• There are 14 weirs and locks originally
constructed for cargo boats to navigate the river
and to divert irrigation water by gravity. They are
still important for recreational boating although
no longer used for cargo ships.
6.
7. Snowy Mountains Scheme
• 5% of the flows in the Murray come from the
snowy river to boost irrigation supplies.
• An agreement ensures that water is diverted
to the Murray at a guaranteed minimum of
1000GL especially in dry periods.
8.
9. Impacts of regulation
• Of the water that would have originally
reached the sea from the Murray-Darling
Basin, over two-thirds is now diverted from its
rivers each year. On some occasions flows
have been so low that water has ceased to
flow to the sea, though it is usually in drought
conditions.
15. Interpreting Graphs
Add another acronym to your toolbelt!
• Trend – what is the general trend? i.e.
growth, decline, stationary
• Example – give specific points/periods from the
graph to back your statement!
• Exception – are there any points/periods on the
graph that do not fit the general trend?
• Quantify – USE NUMBERS AND NAMES.
