PowerPoint

Comments

Transcription

PowerPoint
Reconfiguring the River
Prof Mike Young, Executive Director
Research Chair, Water Economics and Management
The Environment Institute
The University of Adelaide
The 4th Annual Water Symposium,
20 February 2009, Darling Harbour, Sydney
Future Proofing the Basin
(Feb 2008)
Review system size and configuration
Finally, at the time of writing this report, the southern River Murray
System is virtually out of water. Many wetlands have already been
closed, and the level of Lake Alexandrina and Lake Albert is now
below sea level. If this coming winter does not deliver well above
average rainfall, a review of system size and configuration, and, in
particular, a decision as to how best to downsize the entire system
should be undertaken.
It may not be possible to keep all environmental assets and all
irrigation systems going. Parts may have to be abandoned, or
accepted as changed forever.
If significant amounts of rainfall are not received by the end of
August 2008, it would be wise to:
• Commission a formal review of opportunities to downsize and
reconfigure the southern River Murray System.
Volume of Water in the System
Indicative template for sharing and allocating water
Flood water
Volume of water available
Entitlements
Water needed to
ensure conveyance
4
Environment
with a
Environment
fully-specified
share
Shared Water
It’s still dry
Murray Inflows in GL (excluding Snowy & Darling)
Inflows are similar to evaporative losses!
Long drys
TotalTotal
RiverRiver
Murray
System
(including
Darling
River)
Murray
SystemInflows
Inflows (including
Darling
River)
Modelled Current Conditions - Extended Droughts shown in Red
Annual Inflow <= 25 000 GL (GL)
25 000
20 000
WET
DRY
15 000
10 000
5 000
Long-term Median Inflow (9 000 GL/yr)
0
1892
1902
8 yrs
1912
1922
1932
1942
12 yrs
1952
1962
1972
52 yrs
1982
1992
2002
0
2004
300
2004
2001
1998
1995
1992
1989
1986
1983
1980
14% less
2001
1998
1995
1992
1989
1986
400
1983
1980
1977
1974
1971
1968
1965
1962
1959
1956
1500
1977
1974
1971
1968
1965
1962
1959
1956
PERTH
1953
1950
1947
1944
1941
1938
1935
1932
1929
1926
1923
1920
1917
1914
1911
Rainfall (m m )
2000
1953
1950
1947
1944
1941
1938
1935
1932
1929
1926
1923
1920
1917
1914
1911
S tr e a m flo w (G L )
Insufficient planning for less water
Rainfall for Jarrahdale
20%
less
1000
500
0
1000
900
S tre a m in flo w fo r P e rth d a m s (P rio r to S tirlin g D a m )
800
700
600
500
4 8 % le s s
66%
le s s
200
100
With half as much water
Users
Users
Environment
River Flow
Environment
River Flow
Downsize and reconfigure?
Users
Users
Users
Environment
Environment
Environment
River Flow
River Flow
River Flow
Opportunities
1. Downsizing the system
2. Smart environmental asset
management
3. Dynamic river height management
4. Dynamic river salinity management
Downsizing opportunities
• Reduce the system area
– Lake Mokoan, Victoria
– Barren Box Swamp, Murrumbidgee
– Others
•
•
•
•
Reconfigure Lower Lakes?
Reconfigure the Choke and associated forests?
Menindee Lakes?
Other lakes, billabongs, reaches etc?
• Remove some weirs and locks
Smart Asset management
• Defining assets classes
– Ecological value?
– Recreation and other values?
• Prioritizing within asset classes
– Maintain some parts, degree of representation,
etc
• Empower environmental managers to
manage
– 70% of Environmental water entitlements held
in regional trusts
– 100% carry-over of unused water for all with
adjustment for evaporative losses
Smart Unregulated flow management?
Asset targeting
Less water is
required to
optimise the value
of ecological
assets if the
system form can
be manipulated
Source: River Murray Environmental
Management Unit, SA
Source: River Murray Environmental
Management Unit, SA
Source: River Murray Environmental
Management Unit, SA
Source: River Murray Environmental
Management Unit, SA
Dynamic River Salinity Management
• Each Salinity Interception Scheme
included in the entitlement and
allocation regime
– Credits for water released to river
– Debits for groundwater pumped away from
the river
• Seasonal variation in river salinity
• Who is responsible for salinity
impacts from wetlands?
Dynamic river height management
• The biggest dam in the system is on
either side of the river
– Groundwater
• Lowering the river means that
wetlands can be left dry for varying
periods
– But recreation opportunities less
A river infrastructure and environmental asset review?
• Recognising that the system may need
to be operated with much less water,
review and evaluate options to make
more effective use of the river by
– Downsizing the demand that the river
system places on the available water
resource
– Prioritizing and optimising environmental
water use
– Dynamically managing river salinity and
height
Download our reports and
subscribe to Jim McColl and my droplets at
www.myoung.net.au
Contact:
Prof Mike Young
Water Economics and Management
Email: [email protected]
Phone: +61-8-8303.5279
Mobile: +61-408-488.538
www.myoung.net.au

Similar documents