Transcript Dairy and the Murray-Darling Basin Plan

Environmental watering – CEWH 2016
• Improved native fish breeding success: Golden perch,
Silver perch, Murray hardyhead, Bony bream, Murray cod and
rainbowfish and gudgeon species.
• Native bird breeding boom, including first of internationally
protected Eastern great egrets since 2011, following
environmental water to the Yanga National Park in early 2015.
• Significant increases in waterbird species diversity and total
abundance at sites that received environmental water in
Gwydir river system
• Revegetation stabilising banks in Goulburn River system
• Improved dissolved oxygen and black water mitigation
Just add water
• 2750GL and 3200GL targets derived from models aiming to deliver flow rates in river
sections, not environmental outcomes in key indicator or high value sites.
• Assumption that flow targets will deliver overbank flooding to achieve desired
environmental outcomes ‘naturally’.
• Constraints:
• Regulatory, physical, environmental, socio-economic
• Obtaining flood easements
• Upgrading roads, bridge and other infrastructure
• Flood mitigation works – ie, levees
• Increasing dam outlet capacities
• $200 m for above measures
•
Constraints restrict environmental watering to
in-stream, riverbank and lower floodplain.
• Environmental offset works and measures to improve
extent of environmental watering and its success
450GL upwater and relaxed constraints
“Hydrologic modelling of the relaxation of operational constraints in the southern connected system: Methods and
results”. October 2012, MDBA.
Region
Location
Existing constraint
ML/d
Relaxed constraint in
model ML/d
Murray
Hume to Yarrawonga
25,000
40,000
Downstream of
Yarrawonga
22,000
40,000
Weir 32/increase
Menindee outlet
capacity
9300
18,000
Darling Anabranch
Water flows into
anabranch over 9300
ML/d (no regulator)
Regulator added and
closed >9300 ML/d
when water supplied
for enviro in Murray
Gundagai
30,000
50,000
Balranald
9000
13,000
Seymour
12,000
15,000
McCoy’s Bridge
20,000
40,000
Lower Darling
Murrumbidgee
Goulburn
Environmental effects
Flows increased from 60,000 ML/d to 80,000 ML/d at SA border
– 40% of wetlands inundated vs 75% between Darling River and Lock 1
(additional 60,000 ha of Chowilla/Riverland, watering to mid-level floodplain)
Frequency
Pre-1788
Pre-Basin Plan
2800GL
3200=RC
3 years
10 years
8 years
5.5 years
High-flow targets: 450GL, relaxed constraints – possible improved bird breeding
35,000 ML/d for 30 days at Barmah-Millewa forest
40,000 ML/d for 60 days at Gunbower-Koondrook-Perricoota
20,000 ML/d for 150 days at Gunbower-Koondrook-Perricoota*
70,000 ML/d for 42 days at Hattah Lakes
80,000 ML/d for 30 days at Riverland-Chowilla floodplain**
* 27,500 ML/d Swan Hill late October 2016; **94,600 ML/d at SA border last week November 2016
Lower lakes, Coorong and Murray Mouth
Subtle environmental outcomes but environmental indicators unlikely to be particularly
sensitive compared with upstream sites that rely on high flows to inundate mid-high
floodplain levels. (Note: Keystone species Ruppia tuberosa seagrass salinity tolerance range: up to 80-90g/l
Indicator
BP Target
Pre-1788
2009 baseline
2800 GL BP
3200 GL BP - RC
Average salinity in Coorong
southern lagoon
Less than 60g/l
24
62
44
41
Max. days salinity over 130
g/l in southern Coorong
0
0
323
0
0
% years salinity <100 g/l in
southern Coorong
>95%
100%
82%
96%
100%
Average salinity in Coorong
northern lagoon
Less than 20g/l
12
29
21
20
Max. days salinity over 50
g/l in northern Coorong
0
0
604
75
0
Lower Lakes level (mAHD)
0.4m AHD
-0.4m (Jan 2009)
0.4m (Jan 2003)
0.2m (Jan 2009)
0.7m (Jan 2003)
0.2m (Jan 2009)
0.7m (Jan 2003)
Murray mouth bed level
-1m
0.0m (Jan 2009)
-0.5m (Jan 2003)
-0.5m (Jan 2009
-1.5m (Jan 2003)
-0.5m (Jan 2009)
-1.0m (Jan 2003)
-2.5m 2009
-2.5m 2003
MDBA conclusions
“Hydrologic modelling of the relaxation of operational constraints in the southern connected system: Methods and
results”. October 2012, MDBA.
If constraints can be overcome, likely to be increased ecological benefits for
floodplains, particularly if combined with great water recovery. (pxiv)
Work done previously by MDBA shows increasing impacts on communities of water
recovery greater than 2750GL/y, and this was an important consideration in MDBA’s
proposed ESLT. (pxiv)
Overcoming constraints:
“This would require a commitment and significant investment from both State and
Federal governments and would be subject to further assessments, cost/benefit
analysis (including assessments of any third party impacts) and extensive community
consultation.” (piv)
- Federal water special account has $200 million budget for addressing constraints