Social and economic impacts of the Basin Plan in Victoria February 2017

Expected environmental outcomes

The MDBA’s aspiration for the Basin, as expressed in MDBA (2014a) is …we are trying to achieve improvement in the health of the river system — through more natural and variable flows. The expected outcomes are described for river flows and connectivity, vegetation, waterbirds and fish. A summary of environmental outcomes for each from MDBA (2015) is reproduced below.

River flows and connectivity:

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  Maintained base flows at about 60% of natural levels
  

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  Improved overall flow:
  
  • 
    10% more into the Barwon– Darling
    
  • 
    30% more into the River Murray
    
  • 
    30–40% more to the Murray mouth (and it open to the sea 90% of the time)
    

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  Maintained connectivity in areas where it is relatively unaffected - between rivers and floodplains in the Paroo, Moonie, Nebine, Warrego and Ovens
  

• 
  Improved connectivity with bankfull and/or low floodplain flows:
  
  • 
    by 30–60% in the Murray, Murrumbidgee, Goulburn and Condamine–Balonne
    
  • 
    by 10–20% in remaining catchments
    
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  Maintain the Lower Lakes above sea level.
  

Vegetation:

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  Maintenance of the current extent of:
  
  • 
    about 360,000 hectares of river red gum; 409,000 ha of black box; 310,000 ha of coolibah forest and woodlands; and existing large communities of lignum
    
  • 
    non-woody communities near or in wetlands, streams and on low-lying floodplains
    
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  Maintained condition of lowland floodplain forests and woodlands of:
  
  • 
    river red gum
    
  • 
    black box
    
  • 
    coolibah
    
• 
  Improved condition of southern river red gum
  

Waterbirds:

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  Maintained current species diversity of:
  
  • 
    all current Basin waterbirds
    
  • 
    current migratory shorebirds at the Coorong
    
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  Increased abundance - 20–25% increase in waterbirds by 2024
  
• 
  Improved breeding:
  
  • 
    up to 50% more breeding events for colonial nesting waterbird species
    
  • 
    a 30–40% increase in nests and broods for other waterbirds
    

Fish:

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  Improved distribution of key short- and long-lived fish species across the Basin
  
• 
  Improved breeding success for:
  
  • 
    short-lived species (every 1–2 years)
    
  • 
    long-lived species in at least 8/10 years at 80% of key sites
    
  • 
    mulloway in at least 5 out of 10 years
    
• 
  Improved populations of:
  
  • 
    short-lived species (numbers at pre-2007 levels)
    
  • 
    long-lived species (with a spread of age classes represented)
    
  • 
    Murray cod and golden perch (10–15% more mature fish at key sites)
    
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  Improved movement - more native fish using fish passages.
  

Some preliminary work has also been done to estimate the salinity benefits of the recovery, transfer and use of Basin Plan environmental water. Under the Basin Salinity Management 2030 strategy salinity benefits and costs are measured as part of a pollutant-trading framework. Credits are allocated for actions that lower Murray River salinity at Morgan SA and debits are allocated to actions that increase salinity at Morgan.

MDBA (2014b, page 31 and 32) gives very preliminary estimates for Basin Plan dilution flow credits of -58 EC (2,800 GL water recovery scenario). Debits from floodplain watering are estimated at 33 EC. Debits from Basin Plan water recovery projects could also be substantial. Although difficult to quantify at this stage, overall a net salinity credit is expected from Basin Plan water recovery, transfer and use.

3. Measured environmental outcomes

The MDBA, states and the Australian Government work together to monitor, evaluate and report on Basin Plan environmental outcomes. This approach reflects that the work can be done more efficiently as a collective rather than separately. Environmental monitoring projects relate to the key themes of hydrology, inundation, vegetation, waterbirds and fish.

Together with partner governments the CEWO has developed a comprehensive program of operational monitoring and short and long-term intervention monitoring across the Murray-Darling Basin.

Operational monitoring in Victorian reaches and wetlands is carried out by waterway managers or storage managers as part of water deliveries for the VEWH (the Commonwealth transfers allocation to the VEWH for delivery to Victorian rivers and wetlands).

Short-term monitoring by the CEWO is coordinated with other monitoring programs such as Living Murray and the Victorian Environmental Flows Monitoring and Assessment Program (VEFMAP), although each agency supplements monitoring and reports separately, e.g. in the Lower Goulburn River and Lower Broken Creek the CEWO commissioned the University of Melbourne to monitor and report on ecosystem response to environmental water in 2013/14²⁰ (DOE 2016) and the VEWH published the information in Reflections.

The CEWO has established the Long-term Intervention Monitoring Project to monitor and evaluate the contribution of Commonwealth environmental water delivery in the Murray-Darling Basin over five years to June 2019. Monitoring will be undertaken in seven areas including the Goulburn River.

The MDBA acknowledges that it will take some time for the full effects of Basin Plan monitoring to be seen because of lags in biological responses and because the Basin Plan, and associated water recovery, will not be implemented in full until 2024 (MDBA 2015a). Other complicating factors in attributing environmental outcomes to the Basin Plan include natural variability in system condition and Basin Plan implementation being only part, although a signification part, of a much broader integrated program of waterway and catchment management across the Basin.

At this stage the reporting of environmental outcomes is generally short-term and site or event specific. It is also almost as much about learning how river and wetland ecosystems will respond to environmental watering as reporting on responses. For example Table shows reporting on fish and vegetation related outcomes from the use of Commonwealth environmental water in the Lower Goulburn River in 2014/15.

Table : Highlights and implications of environmental watering in the lower Goulburn River in 2014/15 (Source: Table in Executive Summary of Webb et al. 2016)

Matter	Year 2 highlight	Implications for adaptive management
Bankside vegetation abundance and diversity	Areas of the bank inundated by the spring environmental flow events had improved vegetation abundance and diversity pre- to post-flow, while the remainder of the bank showed no effect. This demonstrates the value of bank wetting as the climate grows drier over summer.	We believe that benefits to bankside vegetation may be greater if the first extended spring flow is delivered earlier. This would allow plants to grow in response to bank wetting before air temperatures increase significantly as we move into summer.
Fish assemblages, and the spawning and movement of golden and silver perch	Golden perch exhibited a strong spawning result to spring environmental flows, with eggs and larvae being collected in numbers never before seen following environmental flows. Golden perch also exhibited strong movement responses to environmental flows, mostly moving down the river to spawning areas.	While we are now able to achieve good spawning outcomes for golden perch, adjusting the timing of the second spring fresh will be important for determining how closely spawning is tied to temperature. Future data collection will improve our understanding of the importance of antecedent flows on fish spawning, and whether spawning responses translate to recruitment.