Judy Goode presents a seminar from the second Water Wednesday entitled "Options for the environmental future of the River Murray. Judy Goode is the SA River Murray Environmental Manager for the SA MDB NRM board.

1. The Environment Institute
Water Research Centre
Water Wednesday
Managing the Murray Icon Sites:
can engineering save the
environment

2. WATER
WEDNESDAY
Options for the
environmental future of
the River Murray
Judy Goode
SA River Murray Environmental Manager
SA MDB NRM Board

3. Presentation Outline
– Overview of the River Murray
– Environmental challenges
– Functions and processes
– The Living Murray – Chowilla as a case
study
– The Future?

4. Distribution of Australia’s
surface runoff
20.3%
23.3%
1.0% 0.4% 21.1%
1.9%
0.3%
0%
1.7%
6.1%
10.6%
Source: Water and the
Australian Economy
– April 1999
13.3%

5. What sort of river is the Murray?
Naturally the river is:
– Extremely low gradient (1m:30km from
Lake Victoria to Murray Mouth)
– Slow flowing
– Saline
– Turbid
– A river of extremes
and now in addition to these attributes:
– Highly regulated
– Greatly reduced flow
– Prolonged drought

8. How has the river changed?
• Before diversions and regulation the mean (average) annual runoff
was ~25 000 gigalitres, of which 50% reached the sea after
evapo-transpiration, seepage and retention in wetlands etc
• Between 1920 and 2000, the level of diversion increased from
~2000 gigalitres/year to ~12 000 gigalitres/year
• Extractions tripled in the 50 years to 1994
• In 2000, 61% diversions in NSW, 30% Victoria, 5.5% Queensland
and 3.5% SA – almost equivalent to the mean natural discharge
pre-development
• Changes to flood flows due to storages and regulation
• Contemporary thinking is that a river is likely to exhibit significant
stress if flow regime is reduced below 2/3 of natural (TLM SRP)
• Medium floods reduced from 1:3 to 1:8 years

11. Menindee Lakes
Lake Victoria
Hume Dam
Barmah Choke
Dartmouth Dam

19. Factors Affecting the health of the system
• Significantly fewer floods - changes to flood frequency, timing and duration
due to regulation and over-allocation
• Unseasonal delivery of water to support consumptive uses - high flows
now predominantly delivered in summer/autumn cf natural delivery in
winter-spring
• Limited capacity to deliver water to SA
• Salinity build up on floodplain with limited flooding
• Flow times exacerbating management issues
• Risk of algal blooms due to low flows
• Deterioration of “river health” due to loss of connectivity between the river
and the floodplain
• Conflicting management objectives – eg static water levels for irrigation
and tourism vs weir pool manipulation for environmental outcomes
• Climate change and other risks

20. CSIRO Sustainable Yields Project
• Provides govts with estimate of water availability in the MDB on an
individual catchment and aquifer basis, taking into account climate change
and other risks
• Reduced run off and end of system flows under median and extreme dry
climate change scenarios (assuming current development and allocation
policies, and no recovery of e-water)
– Best estimate median 2030 climate average annual runoff reduced by
10 per cent
– Extreme estimates range from 41% reduction in the Murray (dry
extreme) to 7% increase (wet extreme)
• Significant increases in the average time between beneficial floods
• These hydrologic changes would have very serious consequences for
ecosystem health
• Wet extreme would lead to little change in flood frequency

21. What challenges does this present?
Achieving a balance between the social, economic and
environmental outcomes of water management is a complex
task facing water managers and governments
– Decisions taken in the past exploited the landscape for
development and wealth
– Development over the last 100 years has resulted in biophysical,
landscape scale change that we don‟t fully understand – river
health has declined as the critical connection with floodplains has
been reduced
– Biodiversity has significantly declined, including loss of native
species and changes in vegetation – e.g. native fish populations
estimated to be 10% of original numbers
– The long-term reliability and viability of all users depend on river
health
– We are currently borrowing from the future
What are the shared and individual rights to the natural resources
of the Basin and how are those rights to be managed?

22. What challenges does this present?
The River Murray is a highly regulated river that supports communities and
regional/State economies, at the expense of the environment. How do we
redress the imbalance?
• More water is clearly the answer, but we also:
– Need to „do more with less‟
– Important to identify key environmental assets using scientifically
robust and consistent criteria, prioritisation frameworks and
methodologies
– Take a one-River approach – Basin Plan?
– System approach – scalar
– Restoration projects - identify and agree key ecological processes
– Adaptive management approach – requires significant investment in
monitoring, data interpretation
– Innovative solutions – engineering?
– Make explicit trade-offs and recognise the impacts

23. FUNCTIONS AND PROCESSES
• Owing to the inherent complexity of rivers and an
incomplete understanding of river systems, restoration
projects that focus on reinstating ecological process are
likely to be more successful than those which focus on fixed
end points, particularly when:
 There is a recognition that process and hence restoration
projects are ongoing.
 They are conducted at an appropriate scale.
 They are conducted with appropriate and sufficient scientific
monitoring.
 They are conducted within a multi-disciplinary and adaptive
management framework.
• Restoration of processes focuses on the causes of system
degradation rather than the symptoms

24. Process based river restoration: Time scales
• Long-term strategies for managing flow regimes, land use and
native biota are critical for restoring ecological integrity to rivers
• Temporal considerations are fundamental to river restoration.
 The natural timing, frequency, duration, magnitude and rates
of change of flow are each vital in restoring ecological
processes
• Rare events (e.g. large floods which change river morphology)
are also important and can have long lasting effects
• Temporal considerations need to recognize that natural variability
is an inherent feature of river systems
• Hence restoration of an acceptable range of processes is more
likely to succeed than restoration aimed at a fixed end point

25. Process based river restoration: Spatial scales
• Connectivity is an important ecological process
• Restoration projects should consider key processes and
linkages beyond the channel reach, e.g. upstream/downstream
connectivity, floodplain and hypoheic/groundwater connectivity
• Because physical, chemical, and biological processes are
interconnected in complex ways across river systems, projects
undertaken at this scale are more likely to be successful
• Because both technical and social constraints often preclude
„full‟ restoration , rehabilitation should focus on the causes of
system degradation through attainable reestablishment of
processes and elements

26. Theories and mechanisms of landscape ecology and hydrology
Purposeful move away from traditional focus on
localised restoration to a landscape perspective
(eg. habitat restoration and protection).
• Is there a response to local habitat reintroduction?
• How does the distribution of (restored) habitat influence the
response of plants and animals?
• Where in the landscape should we invest for best outcomes?
• How do we prioritise environmental assets for water and
works?

27. Example – managing individual habitats/issues
Erosion control
Riparian revegetation
Removing willows
Re-snagging
Wetlands
• Often isolated and uncoordinated
interventions at isolated sites
Environmental flows
Source: Nick Bond

28. Example – restoring populations & communities
Spawning habitat
Spawning habitat
Residential
habitat
Refuge
Residential
habitat
habitat
Residential
•Coordinated restoration so habitat
that interactions occur among
‘sites’. Source: Nick Bond

29. Scalable Site Management
Critical Important Optional Desirable
Water Availability
Drought Average Flood
Less More

30. Flow manipulation
Some local benefits but
many higher floodplain
areas still under-watered

31. Picture courtesy Fosters

33. Lake Littra pre-watering
13/9/2004

34. Lake Littra post-watering
23/3/2006

35. Twin Creeks pre-watering 2004

36. Twin Creeks post-watering 2004

37. Monoman Island Horseshoe
pre -watering August 2004
General Description

38. Monoman Island Horseshoe post
watering December 2004

39. Impacts of short-term actions
• Not sustainable long-term
• Does not address issues of connectivity
• Localised and small scale
• Expensive
• Only benefits some communities
• Not system approach
• Dose not necessarily target the highest
priorities

40. Case Study - Chowilla Regulator

41. Current condition

42. Do Nothing 30 yr

43. Chowilla Ck Regulator

47. Natural inundation at 10,000 ML/day

48. Area inundated with regulator at 10,000 ML/day

49. Natural inundation at 70,000 ML/day

50. Regulator Operation
• Can be used at all flows to about 50,000 ML/day
• Levels can be raised up to 19.87 – 3.5 m increase
• Lock 6 to be raised 62 cm to top of piers
• Flow maintained through Chowilla Ck at all times
• Maintenance of velocity is important
• Likely to be operated 1 year in 3 on average
• Preference for >10,000 ML/day QSA for full
operation

51. Flow
20000
40000
60000
80000
100000
120000
0
3/1/77
3/1/78
3/1/79
3/1/80
3/1/81
3/1/82
3/1/83
3/1/84
3/1/85
3/1/86
3/1/87
3/1/88
3/1/89
3/1/90
3/1/91
Year
3/1/92
3/1/93
3/1/94
3/1/95
3/1/96
3/1/97
3/1/98
3/1/99
3/1/00
Recorded flow to SA (1977-2005)
3/1/01
recorded flow to SA
3/1/02
3/1/03
3/1/04
3/1/05

52. Flow
20000
40000
60000
80000
100000
120000
0
3/1/77
3/1/78
3/1/79
3/1/80
3/1/81
3/1/82
3/1/83
3/1/84
3/1/85
3/1/86
3/1/87
3/1/88
3/1/89
3/1/90
3/1/91
Year
3/1/92
9 operations in 29 years
3/1/93
3/1/94
3/1/95
3/1/96
3/1/97
3/1/98
3/1/99
3/1/00
recorded flow to SA
Hypothetical Operational Regime
3/1/01
3/1/02
simulated flow w ith regulator
3/1/03
3/1/04
3/1/05

53. Benefits
• Restoration of a floodplain regime that more
closely resembles natural
• Enable 78% of RRG and 31% Black Box
woodlands to be restored
• Inundation of large areas of other floodplain
communities, including 91% of wetlands and
other watercourses, 75% of river coobah and
58% of floodplain grasslands

54. Risks
• Real time salinity impacts
• Inhibits large bodied fish movement
• Blackwater events
• Weed infestation
• Algal blooms
• Operational objectives?

55. QUESTIONS?