Commonwealth environmental water
use options 2014–15:
Gwydir River Valley
1
Cover image credit: Wandoona Waterhole. Photo: Andy Huxham © CEWO
Acknowledgement of the traditional owners of the Murray-Darling Basin
The Commonwealth Environmental Water Office respectfully acknowledges the traditional
owners, their Elders past and present, their Nations of the Murray-Darling Basin, and their
cultural, social, environmental, spiritual and economic connection to their lands and waters.
© Copyright Commonwealth of Australia, 2014.
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This report should be attributed as ‘Commonwealth environmental water use options 2014–15: Gwydir River Valley,
Commonwealth of Australia 2014’.
The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of the
Australian Government or the Minister for the Environment. While reasonable efforts have been made to ensure that
the contents of this publication are factually correct, the Commonwealth does not accept responsibility for the
accuracy or completeness of the contents, and shall not be liable for any loss or damage that may be occasioned
directly or indirectly through the use of, or reliance on, the contents of this publication.
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Commonwealth environmental water use options
2014–15: Gwydir River Valley
Table of contents
1. Background ........................................................................................................ 5
1.1.
Demonstrating how Commonwealth environmental water in 2014–15 will
contribute to the Basin Plan’s environmental watering plan objectives – Gwydir
River Valley .................................................................................................................................. 5
2. Context for water use in 2014–15 in the Gwydir River Valley ........................ 8
2.1.
Delivering environmental water to the Gwydir River Valley ............................................. 8
2.2.
Operational and management considerations for 2014–15 in the Gwydir River
Valley ........................................................................................................................................... 9
2.3.
Valley condition ....................................................................................................................... 11
3. Water availability ............................................................................................. 14
3.1.
Commonwealth environmental water holdings in the Gwydir River Valley for
2014–15 ...................................................................................................................................... 14
3.2.
Other sources of environmental water allocations .......................................................... 14
3.3.
Natural or unregulated flows and planned environmental water ................................ 15
4. Planning for water use in the Gwydir River Valley in 2014–15 ..................... 16
4.1.
Planning for a range of inflows in 2014–15 .......................................................................... 16
4.2.
Implementing watering actions throughout the year ...................................................... 17
5. Water use options for 2014–15 ........................................................................ 18
5.1.
Summary of watering options ............................................................................................... 18
5.2.
Assessment of environmental watering options ................................................................ 20
5.3.
Options contributing to the Basin Annual Environmental Watering Priorities .............. 30
6. Accounting for the use of Commonwealth environmental water .............. 31
6.1.
Water use accounting ............................................................................................................ 31
6.2.
Monitoring ................................................................................................................................. 31
6.2.1.
Operational monitoring ................................................................................................. 31
6.2.2.
Long term intervention monitoring .............................................................................. 31
7. Next steps – from planning to water delivery ............................................... 33
8. Partnerships ...................................................................................................... 35
9. Bibliography ..................................................................................................... 36
3
List of Figures
Figure 1: The Gwydir River Valley. ............................................................................................................... 9
Figure 2: How inflows may vary and impact on water resource availability over the course
of 2014–15 in the Gwydir River Valley, from a starting point of moderate
resource availability.................................................................................................................... 16
Figure 3: The annual management process for Commonwealth environmental water. .............. 34
List of Tables
Table 1: Expected outcomes from the use of Commonwealth environmental water in the
Gwydir River Valley. ...................................................................................................................... 6
Table 2: Operational considerations for the Gwydir River Valley in 2014–15. .................................. 10
Table 3: Commonwealth environmental water holdings in the Gwydir Valley as at 31 May
2014. ............................................................................................................................................... 14
Table 4: Other potential sources of environmental water in the Gwydir Valley for 2014–15
as at 30 April 2014. ...................................................................................................................... 15
Table 5: Potential watering options for 2014–15 for the Gwydir River Valley. ................................... 19
Table 6: 2014–15 Basin annual environmental watering priorities for the Gwydir River
Valley ............................................................................................................................................. 30
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1. Background
This document is designed to be read in conjunction with the Commonwealth environmental
water use options 2014–15: Planning approach, which outlines the approach to planning for
the use of Commonwealth environmental water this coming water year. The planning
document provides the context for key aspects of the approach including determining
resource availability, the expected outcomes from watering actions and the relationship
between the function of the Commonwealth Environmental Water Office (the Office) and the
Basin Plan.
This document outlines watering options for the use of Commonwealth environmental water in
the Gwydir River Valley this water year. The options, which describe potential watering actions,
series of actions, or watering strategies, do not represent a commitment for water use.
Consistent with the Office’s framework, decisions to make water available for any of the
potential options will be subject to an assessment against five published criteria (available from
the Office’s website) and seasonal, operational and management considerations at the time
of the action. All relevant watering actions will be assessed to ensure the best possible use of
environmental water within the relevant planning area and across the Murray-Darling Basin
and having regard to the Murray-Darling Basin Authority’s Basin annual environmental watering
priorities.
1.1.
Demonstrating how Commonwealth environmental water in 2014–15 will
contribute to the Basin Plan’s environmental watering plan objectives –
Gwydir River Valley
Commonwealth environmental water use options for the Gwydir River Valley in 2014–15 include
the following three flow types:

base flows (low flows)

freshes

overbank flows / terminal wetlands.
These flow types are illustrated in Figure 4 of the document Commonwealth environmental
water use options 2014–15: Planning approach.
Commonwealth environmental water delivery within the Gwydir River Valley may be delivered
to various parts of the river system including:

wetlands

semi-permanent waterholes

and creeks.
The ecological response from delivering Commonwealth environmental water is reflected in
the expected outcomes.
The Office has used the best available information to determine how the expected outcomes
of Commonwealth environmental water contribute towards the objectives of the Basin Plan’s
environmental watering plan. For further information please refer to The Environmental Water
Outcomes Framework at www.environment.gov.au/water/cewo/publications/environmentalwater-outcomes-framework.
5
Table 1 shows the linkage between planned flow types and the expected outcomes for the
Gwydir River Valley. The table also links the short-term expected outcomes to a long-term
contribution to the four Basin Plan objectives at the Basin scale (i.e. biodiversity, ecosystem
function, resilience and water quality).
Table 1: Expected outcomes from the use of Commonwealth environmental water in the
Gwydir River Valley.
Flow Type
Expected outcomes
for 2014–15
Contributions to
longer term outcomes
Contribution to the
following Basin Plan
objective
Base flows (low flows)
Hydrological
connectivity, including
end of system flows
Connectivity
Ecosystem Function
Individual survival and
condition (individual
refuges)
Population condition
(individual refuges)
Resilience
Individual condition
(ecosystem resistance)
Population condition
(ecosystem recovery)
Resilience
Management of water
quality issues (salinity,
dissolved oxygen, pH
and dissolved organic
carbon)
Chemical
Water Quality
Within ecosystem
macroinvertebrate
diversity
Macroinvertebrate
diversity
Biodiversity
Fish condition
Fish diversity
Biodiversity
Fish reproduction, larval
growth and survival
Larval and juvenile
recruitment
Biodiversity
Hydrological
connectivity, including
end of system flows
Connectivity
Ecosystem Function
Mobilisation and
dispersal of biotic and
abiotic materials
Connectivity
Ecosystem Function
Primary production,
decomposition, nutrient
and carbon cycling
Process
Ecosystem Function
Individual survival and
condition (individual
refuges)
Population condition
(individual refuges)
Resilience
Individual condition
(ecosystem resistance)
Population condition
(ecosystem recovery)
Resilience
Management of water
quality issues (salinity,
dissolved oxygen, pH
and dissolved organic
carbon)
Chemical
Water Quality
Vegetation condition
and reproduction
Vegetation diversity
Biodiversity
Freshes
Overbank flows /
terminal wetlands
6
Flow Type
Expected outcomes
for 2014–15
Contributions to
longer term outcomes
Contribution to the
following Basin Plan
objective
Vegetation germination
and dispersal
Vegetation growth and
survival
Biodiversity
Within ecosystem
macroinvertebrate
diversity
Macroinvertebrate
diversity
Biodiversity
Fish condition
Fish diversity
Biodiversity
Fish reproduction, larval
growth and survival
Larval and juvenile
recruitment
Biodiversity
Waterbird survival and
condition
Waterbird diversity and
population condition
Biodiversity
Waterbird reproduction,
recruitment and
fledging
Waterbird diversity and
population condition
Biodiversity
Other vertebrate
reproduction, growth
and survival (frogs)
Adult abundance
(frogs)
Biodiversity
Hydrological
connectivity, including
end of system flows
Connectivity
Ecosystem Function
Mobilisation and
dispersal of biotic and
abiotic materials
Connectivity
Ecosystem Function
Primary production,
decomposition, nutrient
and carbon cycling
Process
Ecosystem Function
Individual survival and
condition (individual
refuges)
Population condition
(individual refuges)
Resilience
Individual condition
(ecosystem resistance)
Population condition
(ecosystem recovery)
Resilience
Management of water
quality issues (salinity,
dissolved oxygen, pH
and dissolved organic
carbon)
Chemical
Water Quality
7
2.Context for water use in 2014–15 in the
Gwydir River Valley
2.1.
Delivering environmental water to the Gwydir River Valley
Flows in the Gwydir River Valley are driven by rainfall in the upper catchment. Almost the entire
runoff for the catchment is generated above Pallamallawa, with the western floodplains
contributing minimal runoff due to low slopes, absorbent soils and high evaporation rates
(Pietsch 2006). Copeton Dam is the major regulated water storage in the Gwydir River Valley.
Copeton Dam has a storage capacity of 1 364 GL and regulates about 55 percent of Gwydir
system inflows (active storage in Copeton Dam is 1 345 GL (CSIRO 2007). Downstream reregulating structures at Tareelaroi, Boolooroo and Tyreel divert flows from the Gwydir River into
the Mehi River, Carole Creek and Lower Gwydir River/Gingham Watercourse, respectively
(Wilson et al. 2009). A number of unregulated tributaries flow into the Gwydir River below the
dam; the Horton River is the primary source of unregulated flows.
The principal wetland areas of the Gwydir River Valley targeted by environmental water are
the lower Gwydir, Gingham Watercourse and Mallowa Wetlands (NSW Department of
Environment, Climate Change and Water [NSW DECCW] 2011). The Gwydir Wetlands is a key
asset in the Gwydir River Valley which forms an inland terminal wetland in the downstream
reaches of the Gwydir River and Gingham Watercourse, below Moree. Four sites in the lower
Gwydir and Gingham are internationally recognised under the Ramsar Convention and other
international agreements for migratory species for their special habitat value for waterbirds.
These are ‘Windella’, ‘Crinolyn’ and ‘Goddard’s Lease’ on the Gingham Watercourse and ‘Old
Dromana’ on the Lower Gwydir Watercourse (NSW Office of Environment and Heritage [NSW
OEH] 2012). When flooded, the wetland sustains up to hundreds of thousands of breeding
colonial waterbirds. The primary ecological features of the wetlands are large expanses of
vegetation, including large areas of coolibah woodland, water couch and the largest stand of
marsh club-rush in New South Wales (NSW) (NSW DECCW 2011; Bowen and Simpson 2010).
The Mallowa Creek breaks off the Mehi River approximately 50 km downstream of Moree. Prior
to the construction of the Mallowa Regulator in 1983, many fresh flows would have passed
through Mallowa Creek and sections of the floodplain. These fresh flows are now diverted
down the Mehi River. While not as extensive as the Gwydir Wetlands the Mallowa Wetlands
supports a diverse wetland and floodplain vegetation assemblage that is representative of
native vegetation of the Gwydir River Valley. Importantly, it also has less of a Lippia presence.
The native vegetation of the Mallowa Creek provides valuable habitat for waterbirds,
woodland birds and other fauna (Torrible et al. 2009).
The Gwydir and Mallowa Wetlands play a substantial part in the biological and ecological
functioning of the Murray-Darling Basin, as the major wetlands in the Basin are not inundated
simultaneously and therefore habitat availability varies across the Basin spatially and
temporally. Since flooding in the Gwydir Wetlands are not always synchronous with flooding of
other Murray-Darling Basin wetlands, such as the Macquarie Marshes or Narran Lake, the
Gwydir Wetlands play an important role on a regional scale.
The Mehi River and Carole Creek are major distributaries of the Gwydir River. Moomin Creek
branches off the Mehi River downstream of Moree and rejoins the River just before its
confluence with the Barwon River at Collarenebri. Carole Creek connects to the Barwon River
through the Gil Gil Creek in the Border Rivers catchment. The Mehi River and Carole-Gil Gil
Creek transport about 6 per cent of the average flow at Pallamallawa to the Barwon River
(Pietsch 2006).
The Sustainable Rivers Audit found that the lowland zone of the Gwydir Valley was rated as
poor for both fish and macroinvertebrates (Davies et al. 2012). Native fish populations in the
8
Gwydir and across the Murray-Darling Basin have been impacted by changes in the natural
flow regime, reduction in habitat quality and availability, and barriers to migration (Copeland
et al. 2003). Changes in the frequency, size, duration and timing of flow events have negatively
impacted on the availability of food, habitat and breeding opportunities for native fish (Rolls et
al. 2013, Baumgartner et al. 2013). The majority of native fish species in the lower Gwydir spawn
during the spring and summer season with rises in water temperature and/or water levels. Up to
20 native fish species occur in the Gwydir catchment with most species still occurring in the
middle Gwydir catchment (Wilson et al. 2009; NSW DECCW 2008).
Figure 1: The Gwydir River Valley.
2.2.
Operational and management considerations for 2014–15 in the Gwydir
River Valley
The delivery of environmental water in the Gwydir River Valley is complex as flow capacities
are greatly reduced in the downstream direction, with the Gwydir River having the greatest
contraction in capacity. A small increase in flows at Pallamallawa can cause over bank flow
downstream. The delivery of environmental water in the Gwydir catchment is also constrained
by a number of other factors, including the release capacities from storages, channel
capacities, proximity of cropping to watercourses, control structures and various operating
practices.
Watering options have been developed in consideration of the release capacities outlined in
the Water Sharing Plan for the Gwydir Regulated River Water Source. The Murray-Darling Basin
Authority has recently published Preliminary Overview of Constraints to Environmental Water
Delivery in the Murray–Darling Basin (Murray-Darling Basin Authority [MDBA] 2013b)and
Constraints Management Strategy 2013 to 2024 (MDBA 2013a) which also provide further
information about constraints to environmental water delivery in the Gwydir Catchment.
9
The distribution of regulated flow in the low lying wetlands depends on the amount of
extraction between the control structures and the wetlands. Where possible, environmental
deliveries will be planned to mimic patterns of natural inundation and ensure core wetland
areas receive water during the warmer summer months for a sufficient period of time.
However, spring and early summer deliveries of environmental water to the wetlands are
constrained by risks to crops within wetland areas during the harvest period.
During periods of peak demand channel capacity is a significant constraint in meeting both
consumptive and environmental demand. Where channel capacity is likely to be exceeded
river operators may rationalise available capacity between water users. This can be
compounded by cropping and harvest cycles pushing environmental water deliveries later in
the season reducing the available time window for delivery to core wetland areas. Under
these circumstances the ecological objectives of environmental water may be at risk due to
compromised delivery of environmental water.
In-stream watering actions, particularly in the Mehi River and Carole Creek, may be timed to
occur prior to the main period for the delivery of irrigation water. Delivery of irrigation water
following an in stream action may contribute to environmental outcomes. While environmental
objectives for such actions target the length of the system the environmental water delivery
must be accounted for at a single point in the system. Extractions downstream of the
accounting point may reduce the environmental outcomes in the lower reaches of the system.
In-stream deliveries to the Mehi River have the potential to contribute to environmental
outcomes in the Barwon-Darling system, downstream of Collarenebri.
Operational considerations such as delivery methods, opportunities, constraints and risks will
differ depending on the inflow scenario and are summarised in Table 2. These considerations
will be assessed throughout the year as decisions to make water available for use are made
and implemented. This includes refining the ecological objectives, assessing operational
feasibility and potential risks and the ongoing monitoring of the seasonal outlook and river
conditions.
Environmental water may be made available for some watering options from the NSW Office
of Environment and Heritage (NSW OEH) either as adaptive environmental water or
discretionary planned environmental water to deliver common and complementary
environmental outcomes.
Table 2: Operational considerations for the Gwydir River Valley in 2014–15.
Inflow scenario
Very low
Opportunities
Manage the recession of naturally
occurring high flows to provide for a
more natural flow pattern.
Use environmental water in
conjunction with, or to maximise the
environmental benefit of, naturally
occurring river flows.
Augment a peak flow and/or
managed recession.
10
Low
Moderate
High
Very high
Inflow scenario
Very low
Low
Moderate
High
Very high
Use environmental water to support
bird reproduction events and aquatic
species propagation/reproduction
requirements
Augment regulated flows to improve
environmental outcomes.
End of system flows contribute to
additional environmental outcomes
in the Barwon-Darling system.
Constraints
Delivery options are limited due to
high unregulated flows resulting in
reduced channel capacity, limiting
the operation of river infrastructure
and inhibiting additional releases
from storages.
Cropping and harvest practices may
reduce available time window for
delivery of environmental water
limiting inundation duration for core
wetlands.
Consumptive orders may dominate
available channel capacity, limiting
the opportunity to contribute
regulated Commonwealth
environmental water.
Risks*
The provision of Commonwealth
environmental water must consider
potential inundation impacts to
property and infrastructure.
*See Section 7 for more information on risk management.
2.3.
Valley condition
Between 2002 and 2010 the Gwydir River Valley experienced an extended period of drought,
which, coupled with river regulation, had a significant impact on the environmental condition
of the valley. Drought breaking inflows were experienced in 2010–11 with very high inflows
experienced across the valley in 2011–12. During 2012–14 there was a return to drier than
average conditions, particularly throughout summer when rainfall was below average while
above average temperatures were experienced.
At the end of the drought in 2010 wetland vegetation was in significant decline. The MDBA’s
second Sustainable Rivers Audit report concluded that the aquatic ecosystems of the Gwydir
River Valley were in poor overall health (Davies et al. 2012). The native fish community and
hydrological condition were rated in poor condition, while the macroinvertebrate community,
riverine vegetation and physical form were rated in moderate condition. In the lowland zone,
where most assets receiving environmental water are located, fish and macroinvertebates
were rated as poor and hydrology as very poor (Davies et al. 2012).
11
Following the drought the priority was to restore native vegetation communities to improve
and increase habitat for a range of fauna species, such as waterbirds. The goal for the use of
Commonwealth environmental water in 2010–13 was to support six to eight months of
continuous inundation in low lying wetland areas for at least three consecutive years to restore
and maintain wetland vegetation in good condition. This frequency and duration of watering
was determined by the known characteristics of the key plant species that occur in the Gwydir
wetlands, namely water couch-spike rush and lignum shrubland. This inundation target was
considered the minimum threshold for maintaining resilience and ensuring the long-term
persistence of these ecosystems (MDBA 2012).
In 2012–13 approximately 42 GL of regulated deliveries of environmental water contributed to
maintaining conditions for growth in the eastern sections of the lower Gwydir River and
Gingham Watercourse. Regulated deliveries did not reach the western sections of these
wetlands due to constrained delivery timeframes as a result of harvest activities and channel
capacity constraints. The wetlands dried down during December however they were
replenished in late February–March as a result of two unregulated flow events.
Monitoring undertaken by NSW OEH confirmed that in response to three successive years of
extended inundation the wetland vegetation extent and condition of communities such as the
marsh club-rush sedgeland (listed as critically endangered under the NSW Threatened Species
Conservation Act 1995) recovered well. Improved inflows also supported recruitment of native
fish and frog species in the Gwydir system. In response to the widespread flooding across the
lower Gwydir floodplain in 2011–12, large numbers of colonial nesting waterbirds
(predominantly ibis and egrets) bred in the wetlands.
After three years of wetting and good recovery of wetland vegetation the Environmental
Contingency Allowance Operational Advisory Committee (ECAOAC) agreed that the strategy
for managing the Gwydir Wetlands in 2013–14 was to follow natural cues. The strategy was to
supplement an unregulated event if there was sufficient flow. In March 2014 an intense fire
burnt through 1 600 hectares of the lower Gwydir wetlands, causing significant damage to the
wetland vegetation. Local rainfall and a small unregulated flow days after the fire was
beneficial in stimulating the initial recovery of the wetland vegetation. Environmental water
could be used in 2014–15 to consolidate the recovery of wetland vegetation.
The Mallowa Wetlands received water for the first time in 2011–12 from small unregulated flows
after a long dry period and the vegetation responded well. This was followed up with
environmental watering from Commonwealth and NSW held water in 2012–13. In 2013–14,
Commonwealth environmental water was delivered to maintain the current extent of wetland
vegetation in a healthy, dynamic and resilient condition providing important refuge habitat for
a range of native species and resulted in a frog breeding event. The Mallowa Wetlands was
the only large wetland site north of the Macquarie Marshes to be watered during the summer
of 2013–14, and provided important drought refuge for a diversity of waterbirds.
2013–14 was also the first year Commonwealth environmental water was used to deliver
environmental water in- stream to achieve outcomes for native fish in the Mehi River and
Carole Creek which are both known habitat for a range of small and large bodied native fish.
This action was developed with, and supported by the ECAOAC and relevant NSW agencies.
The objectives were to increase hydrological connectivity, biotic dispersal, primary production
and access to in-stream native fish habitat such as benches, bars and snags. Short-term
monitoring indicated that the flow was successful in stimulating ecosystem processes of primary
production and carbon cycling which support native fish condition. An increase in native fish
abundance was observed towards the end of summer across all channels.
Environmental water deliveries in the last four years have supported key species to complete
life cycles and contributed to a net improvement in the number and abundance of wetland
species, and overall system health. Threatened aquatic species and vegetation regeneration
12
will require support in the coming water years to ensure their survival and to continue to
improve their condition.
13
3. Water availability
3.1.
Commonwealth environmental water holdings in the Gwydir River
Valley for 2014–15
Commonwealth environmental water holdings available for use in 2014–15 in the Gwydir River
Valley are shown in Table 3below.
Table 3: Commonwealth environmental water holdings in the Gwydir Valley as at 31 May 2014.
Entitlement type
Entitlement held
(GL)
Long-term
average annual
yield (GL)
Estimated
Carryover from
2013–14 (GL)1
Forecast
water
availability
for
2013–14 (GL)2
Gwydir
security)
0.4
0.4
0
80–135
(high
Gwydir (general
security)
89.5
32.2
80
(maximum 112
available within
use limits.)
Gwydir
(supplementary)
19.1
3.6
N/A
Up to 19.1
Total
109.0
36.2
80
Notes:
1. Future decisions about use, transfers and the ability to deliver already approved actions will affect
expected carryover from 2014–15.
2. The forecast for supplementary water is to receive up to the maximum allowed use, subject to the
announcement of trigger flows. Forecasts are based on the best available information including State
forecasts and historical inflow scenarios. Forecasts include carryover from 2013–14. Forecasts are
given to the nearest whole gigalitre for regulated entitlements.
The full list of Commonwealth environmental water holdings can be found at
www.environment.gov.au/topics/water/commonwealth-environmental-water-office/aboutcommonwealth-environmental-water/how-much and is updated monthly.
Portfolio management updates for the Commonwealth’s environmental water holdings are
available at www.environment.gov.au/topics/water/commonwealth-environmental-wateroffice/portfolio-management/portfolio-management.
3.2.
Other sources of environmental water allocations
Other sources of environmental water that may be used to complement Commonwealth
environmental water delivery in the Gwydir River Valley includes water held by NSW OEH. Table
4 below outlines the different environmental water entitlements held by other water holders.
14
Table 4: Other potential sources of environmental water in the Gwydir Valley for 2014–15 as at
30 April 2014.
Source
Management Authority
Assigned water right (GL)
Environmental
Contingency Allowance
(ECA)
NSW OEH (with advice
from the ECAOAC)
Allocations against 45 GL/year
entitlements (15 GL reserved for bird
breeding). Maximum balance – 90 GL
Account balance - 89.31 GL
NSW RiverBank
Environmental Water
Licences
NSW OEH
Allocations against 17.092 GL General
Security entitlements and 0.441 GL of
Supplementary entitlement.
Account balance – less than 1 GL
3.3.
Natural or unregulated flows and planned environmental water
In addition to water entitlements held by environmental water holders, environmental
demands may also be met via natural or unregulated flows and water provided for the
environment under rules in state water resource plans (referred to as ‘planned environmental
water’).
The Water Sharing Plan for the Gwydir Regulated River Water Source provides for planned
environmental water and stock and domestic releases (replenishment flows).
The Gwydir Wetlands often benefit from unregulated tributary flows (downstream of Copeton
Dam) protected under the water sharing plan. The water sharing plan protects up to
500 ML/day of inflows from tributaries downstream of Copeton Dam for the Gwydir Wetlands
(referred to as 3T Water). In addition 50 per cent of high unregulated flows are protected for
the environment with the remaining flow shared across supplementary licences.
Regulated stock and domestic replenishment flows are provided for in the Water Sharing Plan
for use in the following systems if required:

up to 6 GL per year to the Gingham Watercourse (no longer required - replaced with a
stock and domestic pipeline)

up to 4 GL per water year to the lower Gwydir River

up to 6 GL per water year to Mallowa Creek

up to 4 GL per water year to Thalaba Creek

up to 1GL per water year to Ballinboora Creek.
These regulated and unregulated flows offer opportunities to piggy back Commonwealth
environmental water and increase the potential for environmental objectives to be achieved.
15
4. Planning for water use in the Gwydir River
Valley in 2014–15
4.1.
Planning for a range of inflows in 2014–15
In addition to influencing opportunities, constraints and risks in relation to environmental
watering (see Table 2), inflows are a primary driver of resource availability. Resource availability
reflects a combination of the allocations available to the Commonwealth Environmental
Water Holder (Section 3.1) and other environmental water holders (Section 3.2) as well as
natural or unregulated flows and planned environmental water (Section 3.3). Carryover from
2013–14 for the Gwydir is likely to be approximately 80 GL (Table 3). Early season allocations (up
to 31 July 2014) are forecast to be low.
Consideration of this allocation range relative to the total entitlement volume (Table 3) and the
full range of inflows that may be possible suggests that resource availability early in 2014–15
may be moderate. From this starting point, the full range of possible inflows suggests that
resource availability over the course of the year could be between very low and very high
(Figure 2). The full range of possible inflows increases due to decreasing confidence in
anticipating climatic conditions over a longer period of time. As such, the water use options
described in Section 5 have been developed for the full range of resource availability. NSW
State Water Corporation (NSW SWC) has advised that a Bulk Release delivery strategy will be
applied in the Gwydir for 2014–15. While the current resource availability has been assessed as
moderate, some options developed for this scenario may not be pursued due to delivery
constraints.
Figure 2: How inflows may vary and impact on water resource availability over the course of
2014–15 in the Gwydir River Valley, from a starting point of moderate resource availability.
16
4.2.
Implementing watering actions throughout the year
Resource availability will change over the course of 2014–15 as new allocation
announcements are made and water is used or traded. Climatic conditions will also affect the
potential for inflows. The Office will regularly review allocations against environmental
entitlements and seasonal streamflow forecasts over the course of the year to assess resource
availability.
This assessment, along with up to date information on environmental needs and the
operational and management conditions (Section 2) will allow the watering options in
Section 5 to be refined for implementation as required.
17
5. Water use options for 2014–15
5.1.
Summary of watering options
Watering options for 2014–15 for the Gwydir River Valley reflect the approach to supply
Commonwealth environmental water to contribute to the overall environmental objectives
under the Basin Plan’s environmental watering plan. Watering options aim to protect and
restore water-dependent ecosystems and their functions and build resilience to risks and
threats. The overall aim of Commonwealth environmental watering in the Gwydir River Valley
will be to consolidate and protect the ongoing environmental recovery achieved over the last
three years in anticipation of a potentially low rainfall and inflow period.
Watering options have been designed to specifically enable the scaling of actions across
potential inflow scenarios. This provides flexibility for water use to best complement
unregulated inflows and support natural inundation. The provision of Commonwealth
environmental water in combination with small to moderate unregulated freshes would
promote connectivity between wetlands and support permanent and semi-permanent
wetland vegetation recovery and growth, and potentially, recruitment opportunities for a
range of waterbird and native aquatic species (e.g. fish, frogs, turtles, invertebrates), which are
sensitive to environmental triggers such as rising or falling water levels in particular seasons.
Where required, regulated environmental water deliveries will typically seek to enhance low to
moderate flows and support the hydrological requirements of key wetland plant species in the
low lying areas of the wetlands, namely water couch and marsh club-rush. Wetland
vegetation provides critical breeding habitat for waterbirds and other fauna. Consideration will
be given to providing flows to the lower Gwydir area burned in the March 2014 fire to support
its ongoing recovery. River flows will also seek to provide for in-stream refuge sites during
periods of extended low or no flow. Consideration may also be given to augmenting modified
river management practices that may be implemented by river operators in response to low
inflows, such as block releases of consumptive water orders. Where possible, Commonwealth
environmental water will be delivered to benefit multiple sites to maximise the outcomes.
Watering options have not been developed for very high resource availability in recognition
that at these times, large areas of the Gwydir would likely experience large unregulated inflow
events. During large floods, unregulated flows pass overbank and river operators have little or
no influence on how water is distributed on the floodplain and into wetlands. Such flooding
would achieve most environmental outcomes and provision of additional environmental water
would likely cause adverse third party impacts. However, for smaller events under high
resource availability, Commonwealth environmental water may be delivered as floodwaters
recede to extend the overall period of inundation of core wetland areas and increase the
chance of long term ecological outcomes such as successful waterbird reproduction.
Feedback has been sought during the development of water use options for 2014–15 using
existing state frameworks, for example, Environmental Water Advisory Groups and State Water
Customer Service Committees. This feedback has been incorporated into the water use
options where appropriate, particularly in relation to implementation risks and opportunities to
improve outcomes through environmental water delivery.
Any volumes described in the options tables below are approximations only. The final volume
of Commonwealth environmental water made available will depend on river conditions at the
time of use and in consideration of Basin wide needs. The water use options identified do not
represent a commitment for use, nor do they reflect all the possible water use options
available. Additional water use options may be identified throughout the water year. The
Office welcomes information from the community on how environmental water can best be
used and managed. If you have any comments or suggestions, please call 1800 218 478 or
send an email to: ewater@environment.gov.au.
18
Table 5: Potential watering options for 2014–15 for the Gwydir River Valley.
Applicable level(s) of resource
availability
(see Section 4)
Very Low
Low
Moderate
High
Option 1 – Gwydir Wetlands
Provide base flows to
protect vegetation and
maintain drought refuge
habitat for waterbirds.
Option 2 – Mallowa Wetlands
Contribute to base flows and freshes to provide connectivity between wetlands, maintain vegetation extent and
condition, and support opportunities for reproduction for a range of waterbird and other native aquatic species.
Contribute to base flows and freshes to provide connectivity between wetlands,
maintain vegetation extent and condition, and support opportunities for reproduction
for a range of waterbird and other native aquatic species.
Option 3 – Effluent streams of the
Gwydir system (e.g. Lower Gwydir
River, Mehi River and Carole
Creek)
Contribute to base flows to refresh drought refuges and
reduce the risk of degrading water quality.
Contribute to natural and/or regulated flows to support
hydrological connectivity increasing fish habitat
availability, supporting ecosystem processes, improving
native fish condition and supporting opportunities for
breeding.
Option 4 – In-stream low flow base
flow (downstream of Copeton Dam
to lower Mehi River)
Contribute to base flows to refresh drought refuges and
reduce the risk of degrading water quality.
Options unlikely to be pursued under this resource
availability.
Option 5 – Wetland small-bodied
native fish contingency
Contribute to wetland
refugial habitat for smallbodied native fish.
Option 6 – Waterbird reproduction
and fledging contingency
Contribute to natural and/or regulated flows to support
hydrological connectivity increasing fish habitat
availability and supporting fish condition, breeding and
dispersal.
Options unlikely to be pursued under this resource
availability.
Options unlikely to be
pursued under this
resource availability.
If required, augment natural flows to support key
species to complete life cycles in low lying wetlands for
example water bird reproduction and fledging.
Note: Under certain resource availabilities, options may not be pursued for a variety of reasons including that environmental demand may be met by
unregulated flows, and that constraints and/or risks may limit the ability to deliver environmental water.
19
5.2.
Assessment of environmental watering options
Option 1 – Gwydir Wetlands
Catchment: Gwydir
Complex: Gwydir Wetlands
Site: Lower Gwydir and Gingham
Applicable level(s) of resource availability: Very Low to High
Relevant flow component:
Expected inundation extent:
Base flows
Floodplain inundation
Fresh flows
Wetland inundation
Bank-full flows
Over-bank flows
Background:

From 2010–11 to 2012–13 a series of unregulated flows, in combination with
Commonwealth and NSW environmental water, inundated large areas of the Gwydir
Wetlands supporting the recovery of wetland vegetation communities following a long
period of dry conditions and vegetation decline. This period also supported a major bird
breeding event in the northern basin (summer 2011–12).

No significant rainfall occurred in 2013–14 and the Gwydir Wetlands were allowed to enter
a drying phase. While periods of drying are consistent with a natural hydrological regime,
the 2013–14 season was drier than anticipated. Evidence of this was seen where an intense
fire occurred in part of the lower Gwydir wetlands in March 2014. As such, a demand for
critical wetland needs has developed, putting at risk the recovery achieved in 2010–13.

For 2013–14 the ECAOAC agreed that the watering strategy for the Gwydir Wetlands was
to follow natural cues. This was consistent with the agreed strategy of three years of
wetland watering to support recovery and increased resilience of wetland vegetation.
Summary of watering option:

The purpose of the option is to provide flows into the low lying wetland areas along the
Gingham watercourse and lower Gwydir to maintain the benefits of inundation that
occurred during 2010–13 including vegetation condition and extent. Contributing to
maintaining habitat quality and ecosystem diversity will support the survival of flora and
fauna, and ongoing resilience of the Gwydir Wetlands.

Under very low resource availability, the purpose of this option is to provide base flows to
protect core wetland areas from excessive drying. If dry conditions continue in 2014–15, it
will be critical to maintain drought refuges within the Gwydir for waterbirds and other
fauna. Maintaining refugial habitat will be important not only within the Gwydir River Valley
but also at the scale of the northern Murray-Darling Basin.

The preference is for the provision of Commonwealth environmental water in combination
with unregulated flows. Commonwealth supplementary water (if access is triggered) could
be used to protect a proportion of naturally occurring small to moderate fresh flows.
Deliveries from the dam will typically seek to enhance low to medium in-channel river flows
and inundation of low lying wetland areas.
Timing
All year (most likely spring to autumn)
Volume of Commonwealth
environmental water
Up to 50 GL (including up to 10.1 GL of supplementary water, if
access triggered).
Total volumes including NSW held and planned environmental
water are to be confirmed.
20
Action undertaken in this catchment
previously:
Yes
Similar action has been undertaken elsewhere
in the Murray Darling Basin:
Yes
No
No
Operational considerations and feasibility:

This option will be coordinated with NSW OEH to ensure complementary delivery. NSW OEH
manage held and planned environmental water for NSW (the Environmental Contingency
Allowance).

Where possible this option will be avoided during winter cropping periods to minimise third
party impacts (e.g. planting and harvest).

In delivering environmental flows to the Gwydir Wetlands, early season ‘pre-wetting’
watering may maximise benefits and mitigate against channel capacity constraints later in
the season. Pre-wetting would be restricted to in-channel flows to minimise third party
impacts and timed to maximise the growth of native wetland vegetation. Pre-wetting will
only be considered where there are complementary control measures to minimise the risk
of spreading weeds, such as Lippia (Phyla canescens).

Target events will be selected taking into account factors including likely alteration of the
natural hydrograph, period since last similar event, seasonality, species likely to benefit,
potential risks (including undesirable inundation of winter crops), secondary benefits and
volume of water required.

This option may not be required if other flows (e.g. high unregulated flows) occur that are
sufficient to contribute to vegetation recruitment and extent, and survival and growth of
native species.
Stakeholder feedback:

NSW OEH has advised that Lippia will respond more quickly than native species with late
autumn/winter flows and therefore have a growing advantage over natives. For this
reason, should a pre-watering strategy be employed, in-channel flow commencing in
spring is the preferred option.

The ECAOAC supports environmental watering in the Gwydir Wetlands in 2014–15 in
consideration of the dry conditions experienced in 2013–14 and to support the post-fire
recovery of the marsh club-rush sedgeland on ‘Old Dromana’. Consistent with previous
years of environmental watering, delivery of environmental water will remain in-channel
until harvest is complete.
21
Option 2 – Mallowa Wetlands
Catchment: Gwydir
Complex: Other Gwydir Catchment Sites
Site: Mallowa Wetlands
Applicable level(s) of resource availability: Very Low to High
Relevant flow component:
Expected inundation extent:
Base flows
Floodplain inundation
Fresh
Wetland inundation
Bank-full flows
Over-bank flows
Background:

Following an extensive dry period, the Mallowa Wetlands received environmental water in
2012–13 and 2013–14. The vegetation has shown good signs of recovery and its habitat
value has been demonstrated by a high number of waterbird species visiting over this
period. The Mallowa Wetlands was the only site north of the Macquarie Marshes to receive
water in spring–summer 2013–14, providing critical drought refuge in the northern Basin

The Mallowa Wetlands received small unregulated flows in 2011–12, and delivery of
environmental flows further increased inundation extent in 2012–14. With the dry conditions
in 2013–14 a further year of wetting would be beneficial to build on the outcomes
achieved to date by supporting the recovery of the wetlands and building the resilience of
the system.
Summary of watering option:

Inundation in 2014–15 would support hydrological connectivity between wetlands, further
recovery of vegetation extent and condition, as well as provide habitat for a range of
waterbirds and native aquatic species (e.g. fish, frogs, turtles, invertebrates). Contributing
to improved habitat quality and increased within-ecosystem diversity would support
survival and successful reproduction of native birds, fish and other fauna.

Under very low resource availability, the purpose of this option is to provide base flows to
protect core wetland areas from excessive drying. If dry conditions continue in 2014–15, it
will be critical to maintain drought refuges within the Gwydir for waterbirds and other
fauna. Maintaining refugial habitat will be important not only within the Gwydir River Valley
but also at the scale of the northern Murray-Darling Basin.

The preference is for the provision of Commonwealth environmental water in combination
with unregulated flows. Commonwealth supplementary water (if access is triggered) could
be used to protect a proportion of naturally occurring small to moderate fresh flow.
Deliveries from the dam will typically seek to enhance low to medium in-channel river flows
and inundation of low lying wetland areas.
Timing
All year (most likely spring to autumn)
Volume of Commonwealth
environmental water
Up to 20 GL
Total volumes including NSW held and planned environmental
water are to be confirmed.
Action undertaken in this catchment
previously:
Yes
Similar action has been undertaken elsewhere
in the Murray Darling Basin:
No
Yes
22
No
Operational considerations and feasibility:

This option will be coordinated with NSW OEH to ensure complementary delivery. NSW OEH
manage held and planned environmental water for NSW (the Environmental Contingency
Allowance).

Where possible this option will be avoided during winter cropping periods to minimise
inconvenience to landholders.

Delivery is constrained to channel capacity at Mallowa Creek offtake. Commonwealth
environmental water will be accounted for at Mallowa Creek offtake. If a pre-wetting
strategy were to be employed prior to the harvest of winter crops Commonwealth
environmental water will be delivered at a lower flow rate to avoid breakouts from the
main channel.

This option may not be required if other flows (e.g. stock and domestic replenishment flows)
are adequate to support vegetation recruitment and extent, and survival and growth of
native species.
Stakeholder feedback:

NSW OEH has advised that after several consecutive years of watering the response of the
wetland vegetation in the Mallowa has been very positive, attracting a variety of
waterbird species. However, considering its highly degraded condition prior to 2011, the
recovery of the Mallowa could benefit from further watering in 2014–15.

The ECAOAC supports the existing strategy of 3 years of watering in the Mallowa Wetlands.
Ongoing communication with landholders on the timing and duration is critical. Consistent
with previous years of environmental watering, delivery of environmental water will remain
in-channel until harvest is complete.
23
Option 3 – Effluent streams of the Gwydir system
Catchment: Gwydir
Complex: Gwydir Catchment River Flows
Site: In-stream e.g. lower Gwydir River, Mehi River, Moomin Creek and Carole Creek.
Applicable level(s) of resource availability: Very Low to High
Relevant flow component:
Expected inundation extent:
Base flows
Floodplain inundation
Fresh flow
Wetland inundation
Bank-full flows
Over-bank flows
Background:

The Gwydir River Valley is known habitat for a range of native fishes including large-bodied
species such as Murray cod, golden perch and freshwater catfish. A number of smallbodied species also occur in the Gwydir such as Murray Darling rainbowfish, spangled
perch and bony bream. The second Sustainable Rivers Audit rated the condition of fish
communities in the Gwydir River Valley as poor. The health of higher trophic levels such as
fish community composition and abundance is a good indicator of overall ecosystem
health.
Summary of watering option:

The purpose of the option is to enhance in-stream flows by contributing to regulated and
unregulated flows along the effluent streams of the Gwydir system to the end of the system.
This will support in-stream ecological function and nutrient cycling, contributing to the
health of in-stream habitat and maintaining water quality. Connecting and extending the
wetted period of benches and anabranches with the main channel will contribute to
nutrient cycling, driving food production for native fish species and other aquatic fauna
such as shrimp.

The provision of Commonwealth environmental water in combination with regulated
(including irrigation deliveries) or unregulated flows will support native fish condition and
reproduction by providing improved opportunities for fish to access habitat to feed, find
shelter and reproduce. The option aims to stimulate fundamental in-stream ecological
processes to provide improved conditions for spawning. Increasing the opportunities for
recruitment of small bodied species is likely to benefit large bodied species such as Murray
cod and golden perch. Recruitment of golden perch is known to happen in the lowland
areas of the catchment.

Under very low to low resource availability, the purpose of this option is to provide base
flows to protect refugial in-stream habitat such as pools, and mitigate against declining
water quality.

Under moderate to high resource availability the purpose of this action is to augment
regulated and unregulated flows at key times known to be important for native fish
outcomes, to extend the duration of flow events, mitigate against sudden drops in flow,
and provide a tapered flow recession. Commonwealth supplementary water (if access is
triggered) could be used to protect a proportion of unregulated fresh flows.
Timing
All year, most likely spring to summer
Volume of Commonwealth
environmental water
Up to 20 GL (including up to 9 GL of supplementary water, if
access triggered)
24
Action undertaken in this catchment
previously:
Yes
Similar action has been undertaken elsewhere
in the Murray Darling Basin:
No
Yes
No
Operational considerations and feasibility:

This option will be coordinated with NSW OEH to ensure complementary delivery. NSW OEH
manage held and planned environmental water for NSW (the Environmental Contingency
Allowance).

Water may not be delivered to all three streams. Outcomes may also be achieved in
delivering water for other actions (e.g. in the Gwydir River in delivering water to the Lower
Gwydir and Gingham Watercourse). Delivery of water will be prioritised based on the water
available, presence and condition of suitable in-stream habitat and predicted stream flow
during the event (regulated and unregulated water sources).

The ecological requirements of native fish species vary in terms of spawning time, water
temperature, in-stream habitat requirements and preferred flow regime. Native fish species
in the Gwydir typically reproduce during spring and summer associated with an increase in
flow and water temperatures.

Deliveries in winter may provide adult fish opportunities to feed and grow before they
reproduce. Providing flows that access in-channel habitat in September to October would
coincide with the smaller spawning ‘window’ (water temperature related) of Murray cod
and catfish. Larvae and juveniles of these species have been recorded in fish surveys in late
September–early October in northern Murray-Darling Basin valleys. Deliveries during spring
to summer may contribute to larval dispersal, larval/juvenile fish growth and survival.

Target events will be selected taking into account factors including likely alteration of the
natural hydrograph, period since last similar event, seasonality, species likely to benefit,
potential risks (including cold water pollution from dam releases), secondary benefits
(including where water provided in the Mehi River could contribute to flow requirements in
downstream systems) and volume of water required.

Should no suitable supplementary or unregulated event occur, held environmental water
may be used to deliver the full flow event.

Should special delivery arrangements be introduced in response to very dry conditions,
such as the block release of irrigation orders, environmental water may be used to
augment these releases to provide hydrological connectivity to the end of the system.

Consideration will also be given to coordinating delivery such that return flows are used to
contribute to downstream outcomes, namely longitudinal connectivity (especially under
very low to low resource availability scenarios where end of catchment discharge would
otherwise be negligible).
Stakeholder feedback:

The ECAOAC supports the use of environmental water to improve outcomes for native fish
in the Gwydir.

Gwydir Valley Irrigators Association provided the Office with a number of recommendations
in response to the 2013–14 in-stream watering action relating to decision making processes
and exploring opportunities for joint delivery options with irrigation communities to achieve
outcomes as efficiently as possible.

The Office welcomes advice on opportunities, where practical, to integrate irrigation
delivery and environmental water to achieve environmental outcomes while not
compromising irrigation delivery.

The Office works closely with delivery partners in the design and implementation of
watering actions in the Gwydir, including NSW OEH, NSW Office of Water, NSW Fisheries and
NSW SWC.
25
Option 4 – In-stream low flow base flow
Catchment: Gwydir
Complex: Gwydir Catchment River Flows
Site: downstream of Copeton Dam to lower Mehi River
Applicable level(s) of resource availability: Very Low to Low
Relevant flow component:
Expected inundation extent:
Base flows
Floodplain inundation
Fresh
Wetland inundation
Bank-full flows
Over-bank flows
Background:

Under a sustained low inflow scenario, Commonwealth environmental water deliveries
could contribute to maintaining natural water levels in pools and flowing water in channel
to keep in-stream habitat wet, water quality safe, and provide drought refuge for a range
of aquatic species. Maintaining drought refuge habitat is a key factor for influencing the
survival of aquatic species during dry years.
Summary of watering option:

The purpose of the option is to provide hydrological connectivity to in-stream habitat, to
ensure the persistence of pools as refuge, and to reduce the risk of degrading water quality
conditions (particularly low dissolved oxygen levels).

The proposed option would occur after a protracted period of low flow to maintain
essential refuge habitat for aquatic species and fundamental ecosystem functions.

To achieve this outcome, Commonwealth environmental water will contribute to flows as
required. Commonwealth environmental water will be delivered as in-channel flows from
regulated entitlements and managed within the normal water delivery arrangements.
Timing
All year (subject to low flow triggers)
Volume of Commonwealth
environmental water
Up to 15 GL
Action undertaken in this catchment
previously:
Yes
Similar action has been undertaken elsewhere
in the Murray Darling Basin:
No
Yes
No
Operational considerations and feasibility:

This delivery option would be delivered by supplementing other water sources (such as
irrigation deliveries) to provide longitudinal connectivity and extend the duration of access
to a range of habitats.

Should special delivery arrangements be introduced in response to very dry conditions,
such as the block release of irrigation orders, environmental water may be used to
augment these releases to provide hydrological connectivity to the end of the system.

This option will be coordinated with NSW OEH to ensure complementary delivery. NSW OEH
manage held and planned environmental water for NSW (the Environmental Contingency
Allowance).
Stakeholder feedback:

The ECAOAC supports the use of environmental water to protect refuge sites from drying
down completely, which is a risk during river operations under block releases.
26
Option 5 – Wetland small-bodied native fish contingency
Catchment: Gwydir
Complex: Gwydir Wetlands
Site: semi-permanent waterholes e.g. lower Gwydir and Gingham
Applicable level(s) of resource availability: Low to High
Relevant flow component:
Expected inundation extent:
Base flows
Floodplain inundation
Fresh
Wetland inundation
Bank-full flows
Over-bank flows
Background:

The life history stages of some small bodied fish species involve dispersal onto the floodplain
during large flooding events to reproduce. There are a number of waterholes in the lower
Gwydir and Gingham that fill during large flooding events and become important habitat
for a number of small bodied fishes (e.g. olive perchlet). As the floodwaters recede, fish
may become stranded in these waterholes until the next flood event.

In 2013–14 the olive perchlet (Ambassis agasisizii) (endangered population Fisheries
Management Act 1994 (NSW)) was observed for the first time in the Gwydir catchment in
the Boyanga Waterhole and Gingham Waterhole, on the Gingham watercourse.

Many native fish species that used to be widespread in the Murray-Darling Basin now have
patchy distributions. Protecting known populations, where possible, in between wet years is
important to enhance these species’ capacity to recolonise suitable habitat during higher
flow periods.
Summary of watering option:

The purpose of this option is to provide water to semi-permanent waterholes such as in the
lower Gingham and Gwydir to protect refugial habitat for small-bodied native fish.

While these waterholes are semi-permanent and are prone to natural drying, it may be
feasible to provide additional water to maintain water levels and mitigate degrading water
quality, sustaining refugial habitat for native fish until a flood event reconnects the
waterholes with the channel.
Timing
All year, most likely spring to summer
Volume of Commonwealth
environmental water
Up to 10 GL
Action undertaken in this catchment
previously:
Yes
Similar action has been undertaken elsewhere
in the Murray Darling Basin:
No
Yes
No
Operational considerations and feasibility:

The feasibility of this action will be determined by the ecological requirements of the native
fish species detected in any waterholes, and the practicality of delivering water to sites. The
decision to undertake this option will also depend on the seasonal outlook, time since last
flood and likelihood of persistence of any stranded populations.

Information, recommendations and cooperation between delivery partners such as NSW
OEH, NSW DPI Fisheries, NSW SWC and NSW Office of Water is important.

This option could be incorporated with other delivery options.
Stakeholder feedback:
27

No specific feedback received.
Option 6 – Waterbird reproduction and fledging contingency
Catchment: Gwydir
Complex: Gwydir Wetlands
Site: Gwydir Wetlands, Mallowa Wetlands
Applicable level(s) of resource availability: Moderate to High
Relevant flow component:
Expected inundation extent:
Base flows
Floodplain inundation
Fresh flows
Wetland inundation
Bank-full flows
Over-bank flows
Background:

The wetlands in the Lower Gwydir system are recognised as being of international
importance under the Ramsar Convention and other migratory bird agreements. It is an
important breeding area for waterbirds as well as resting and staging points for migratory
bird species. When flooded, the wetland sustains up to hundreds of thousands of breeding
colonial water birds, which feed in the wider wetland area.

Species that breed in the Gwydir Wetlands include: little egret, intermediate egret, great
egret, nankeen night heron, straw-necked ibis, Australian white ibis, glossy ibis and magpie
geese.
Summary of watering option:

The purpose of the option is to support waterbird reproduction events. If a waterbird
reproduction event commences but system inflows are not sufficient to sustain water levels
in the area, additional environmental water may be required to support fledging of chicks.
In these circumstances, additional environmental water may be provided to reduce the risk
that adult birds would abandon nests and the waterbird reproduction event would be
unsuccessful.
Timing
Spring/Summer/Autumn
Volume of Commonwealth
environmental water
Up to 10 GL
Action undertaken in this catchment
previously:
Yes
Similar action has been undertaken elsewhere
in the Murray Darling Basin:
No
Yes
No
Operational considerations and feasibility:

This option will be coordinated with NSW OEH to ensure complementary delivery. NSW OEH
manage held and planned environmental water for NSW (including the Environmental
Contingency Allowance).

Colonial waterbird reproduction sites along the Gingham watercourse are most likely to
require support by deliveries. The precise location of the potential watering event will
become apparent should reproduction commence. The volume and delivery pattern will
be highly dependent on the location of the waterbird reproduction event, the degree to
which it requires support and whether support from environmental water deliveries is
feasible.

This option may not be required if other flows (e.g. natural flood flows) are sufficient to
support the waterbird reproduction to completion. This option could be incorporated with
28
other delivery options.
Stakeholder feedback:

The ECAOAC and other delivery partners agree that it would be highly undesirable for a
breeding event to be triggered and to fail. General consensus from relevant stakeholders is
to provide support as needed to ensure breeding events are successful.
29
5.3.
Options contributing to the Basin Annual Environmental Watering
Priorities
Each year the Murray-Darling Basin Authority develops Basin annual environmental watering
priorities (‘Priorities’). All environmental watering in the Murray-Darling Basin, including the use
of both held and planned environmental water, is to be undertaken having regard to the
Priorities.
The Priorities are not an exhaustive list of all important assets and functions throughout the Basin
and hence do not exclude other watering actions undertaken by environmental water holders
and managers.
The 2014–15 Basin annual environmental watering priorities were published on 30 June 2014
and are available here: www.mdba.gov.au/what-we-do/environmental-water/environmentalwatering-priorities/priorities-14-15. Table 6 identifies the relevant Priorities for the Gwydir River
Valley and the watering options that could contribute to achieving the identified outcomes.
Table 6: 2014–15 Basin annual environmental watering priorities for the Gwydir River Valley
2014–15 Basin annual environmental watering
priorities relevant to the Gwydir River Valley
Watering options that may contribute to the
achievement of priority outcomes
Theme: Connect rivers and floodplains
Gwydir wetlands: Improve the condition and
maintain the extent of wetland vegetation
communities in the Gwydir Wetlands
(including Ramsar sites) by restoring
hydrological connectivity and a flow regime
that meets ecological requirements.
Option 1 – Gwydir Wetlands
Option 2 – Mallowa Wetlands
Theme: Enhance and protect refuge habitat
Native fish in the northern Basin: Improve
survival of native fish populations by
enhancing and protecting dry period refuge
habitat in the northern Basin
Option 1 – Gwydir Wetlands
Option 3 – Effluent streams of the Gwydir
system
Option 4 – In-stream low flow base flow
Option 5 – Wetland small-bodied native fish
contingency
Waterbird Refuge: Maintain waterbird habitat,
including refuge sites, and food sources, to
support waterbird populations across the
Murray-Darling Basin. Support waterbird
breeding, where feasible
Option 1 – Gwydir Wetlands
Option 2 – Mallowa Wetlands
Option 6 – Waterbird reproduction and
fledging contingency
30
6. Accounting for the use of Commonwealth
environmental water
6.1.
Water use accounting
Across NSW, Commonwealth environmental water is generally transferred to NSW OEH’s
environmental accounts. NSW OEH is then responsible for making arrangements to deliver the
environmental water with river operators such as NSW SWC. In some instances, water may be
delivered without transferring it to NSW OEH environmental accounts.
River flows will be accounted for at storages or at downstream flow gauges and will be
reported to the Office by NSW OEH. Where applicable, water delivered to individual wetland
sites will be accounted at flow gauges or metered pumps at those sites.
6.2.
Monitoring
6.2.1. Operational monitoring
Operational monitoring is monitoring that helps assess whether water has been delivered as
planned [e.g. the volumes, timing (frequency and duration), and location and flow rates of
water delivered] and can include observations of immediate environmental responses.
This monitoring is mostly undertaken by delivery partners in conjunction with the Office. In the
Gwydir River Valley, this includes the NSW OEH, NSW SWC, and NSW Office of Water.
Delivery partners provide regular operational monitoring updates to the Office. The operational
monitoring requirements are set out in the Office’s Operational Monitoring template.
Key parameters required through operational monitoring are:

date of Commonwealth environmental water delivery (commencement and finish)

point of debit/delivery (both if they are different)

volume of Commonwealth environmental water delivered (provided on a weekly basis)

flow rate that water is delivered at (hydrograph of delivery if possible)

monitoring associated with identified risks.
6.2.2. Long term intervention monitoring
The Long Term Intervention Monitoring Project (LTIM Project) is the primary means by which the
Office will undertake monitoring and evaluation of the ecological outcomes of
Commonwealth environmental watering. The LTIM Project will be implemented at seven
Selected Areas over a five year period from 2014–15 to 2018–19 to deliver five high level
outcomes (in order of priority):
1. evaluate the contribution of Commonwealth environmental watering to the objectives of
the MDBA’s Environmental Watering Plan
2. evaluate the ecological outcomes of Commonwealth environmental watering at each of
the seven Selected Areas
31
3. infer ecological outcomes of Commonwealth environmental watering in areas of the
Murray-Darling Basin that are not monitored
4. support the adaptive management of Commonwealth environmental water
5. monitor the ecological response to Commonwealth environmental watering at each of the
seven Selected Areas.
This approach has a sound scientific basis that allows the Office to understand environmental
outcomes in catchments where around 90 per cent of Commonwealth environmental water is
held. A Monitoring and Evaluation Adviser will undertake evaluation at the Basin scale.
The seven Selected Areas where monitoring will occur are:
1. Junction of the Warrego and Darling rivers
2. Gwydir River system
3. Lachlan River system
4. Murrumbidgee River system
5. Edward-Wakool River system
6. Goulburn River
7. Lower Murray River.
These areas were chosen to be representative of Commonwealth environmental watering
across the Murray-Darling Basin.
A Monitoring and Evaluation Plan that captures the long-term arrangements between
scientific organisations and delivery partners has been developed for the Gwydir River system
Selected Area.
Results from the LTIM Project will be published on the Office’s website and the data will be
publicly available.
32
7. Next steps – from planning to water
delivery
Local knowledge and experience is critical to effectively manage and deliver Commonwealth
environmental water. Stakeholders have an important role and provide critical information that
informs each stage of the process for managing Commonwealth environmental water (see
Figure 3).
The planning phase is the first stage in the cycle of environmental water management. The
planning process occurs on an annual basis between January and the end of June, and each
planning document represents the culmination of months of work and consultation.
Throughout the planning process the Office consults closely with state environmental water
managers, river operators and local environmental water advisory groups. The information
gathered as part of the planning process feeds into the development of the options for the
following water year.
Towards the beginning of the new water year the focus shifts from planning to implementation.
Greater consideration is given to current and forecast catchment conditions and water
availability to determine which of the options identified during the planning process can
feasibly be implemented. Local on-ground knowledge is important for detailing a specific
watering action including the flow magnitude, timing, triggers for commencement, rates of rise
and fall and the area to be inundated. Once an action has been scoped in more detail an
assessment against the following criteria is undertaken:

ecological value of the river, floodplain or wetland

expected outcomes from watering

potential risks of watering

long-term sustainability and management of the site

cost effectiveness and feasibility of watering.
Site managers and local community groups provide important information to inform these
assessments. In particular, information related to potential risks provides critical input to the
detailed risk assessment that is undertaken before a decision is made on a watering action. For
further information see the Framework for Determining Commonwealth environmental water
use (available at: www.environment.gov.au/resource/framework-determiningcommonwealth-environmental-water-use.
Following the scoping and assessment of potential watering actions, the Commonwealth
Environmental Water Holder is required to make a decision on whether or not to commit the
water and funds required to support the watering action. In doing so the Commonwealth
Environmental Water Holder also has regard to the Basin Annual Priorities as required by the
Basin Plan.
When a decision is made by the Commonwealth Environmental Water Holder to proceed with
a watering action arrangements for implementation are made with delivery partners. This
includes river operators, who manage the delivery of the water and operational monitoring.
Local community involvement is crucial at this stage of implementation and during water
delivery as conditions can change rapidly and may result in the need to adjust, suspend or
even cancel the watering action.
33
Upon completion of the watering action, a review process, which generally takes place from
March through to October, informs future watering actions and long-term management. This
review is informed by the weekly operational monitoring, results of ecological monitoring, and
feedback provided by site managers and the local community.
IMPLEMENTATION
Detailed planning and
scoping of feasible
watering actions
Approval of Water
Use Options
documents by CEWH
Preparation of
paperwork for decision
includes assessment
against criteria
Assessment of
catchment conditions
Eliminate
unrealistic/
unfeasible
options
Detailed risk assessment
Decision by CEWH
Change, suspend or
cancel watering
actions to reflect
changing conditions
REVIEW
Implementation of
watering action
Ongoing weekly
operational monitoring
Watering action
finished – acquittal
report
Stakeholder input to CEWO required
Mar - Oct 2015
Annual planning for
Commonwealth
environmental water
use options
Jun 2014- Jun 2015
Jan– Jun 2014
PLANNING
Completion of all
watering actions within
a catchment –
Watering Action
Review
Ecological monitoring:
• Short term ecological
monitoring by other
agencies
• Long Term
Intervention Monitoring
Figure 3: The annual management process for Commonwealth environmental water.
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8.Partnerships
The Office has consulted with a range of stakeholders to develop the Commonwealth
environmental water use options for the Gwydir River Valley for 2013–14, including our delivery
partners as follows:

Murray-Darling Basin Authority

New South Wales Office of Environment and Heritage

New South Wales Office of Water

New South Wales Department of Primary Industries

New South Wales State Water Corporation

North West Local Land Services.
The Office will continue to work with stakeholders and other interested community members in
the planning, delivery, management and monitoring of Commonwealth environmental water.
35
9. Bibliography
Baumgartner, L. J., Conallian, J., Wooden, I., Campbell, B., Gee, R., Robinson, W. A. and
Mallen‐Cooper, M. (2013). Using flow guilds of freshwater fish in an adaptive management
framework to simplify environmental flow delivery for semi‐arid riverine systems. Fish and
Fisheries, Early View (Online Version of Record).
Bowen, S. and Simpson, S. L. (2010). Changes in Extent and Condition of the Vegetation
Communities of the Gwydir Wetlands and Floodplain 1996-2008: Final Report to the NSW
Wetland Recovery Program. NSW Department of Environment Climate Change and Water,
Sydney.
Copeland, C., Neller, S., Schooneveldt-Reid, E., Wales, N. S. and Fisheries, N. (2003). Fish
Everywhere: An oral history of fish and their habitats in the Gwydir River. NSW DPI Fisheries.
CSIRO (2007). Water availability in the Gwydir. A report to the Australian Government from the
CSIRO Murray-Darling Basin Sustainable Yields Project. , CSIRO, Australia.
Davies, P., Stewardson, M., Hillman, T., Robert, J. and Thoms, M. (2012). Sustainable Rivers Audit
2: The ecological health of rivers in the Murray–Darling Basin at the end of the Millennium
Drought (2008–2010). Volume 2. Murray-Darling Basin Authority, Canberra.
Murray-Darling Basin Authority (2012). Assessment of environmental water requirements for the
proposed Basin Plan: Gwydir Wetlands. Murray-Darling Basin Authority, Canberra.
Murray-Darling Basin Authority (2013a). Preliminary Overview of Constraints to Environmental
Water Delivery in the Murray–Darling Basin. [online] available: www.mdba.gov.au/mediapubs/publications/constraints-overview, accessed 12 June 2014.
Murray-Darling Basin Authority (2013b). Constraints Management Strategy 2013 to 2024. [online]
available: www.mdba.gov.au/what-we-do/water-planning/managing-constraints, accessed
12 June 2014.
NSW Department of Environment, Climate Change and Water (2008). Final report on the
Gwydir waterbird and fish habitat study. NSW Wetland Recovery Program. Rivers and Wetlands
Unit, NSW Department of Environment and Climate Change, Sydney.
NSW Department of Environment, Climate Change and Water (2011). Gwydir Wetlands
Adaptive Environmental Management Plan., NSW Department of Environment Climate
Change and Water, Sydney.
NSW Office of Environment and Heritage (2012). Gwydir Wetlands: Gingham and Lower Gwydir
(Big Leather) Watercourses Ramsar site. [online] available:
www.environment.nsw.gov.au/wetlands/GwydirWetlandsGinghamAndLowerGwydirBigLeather
Watercourses.htm, accessed 12 June 2014.
Pietsch, T. J. (2006). Fluvial geomorphology and late quaternary geochronology of the Gwydir
fan-plain. PhD, University of Wollongong.
Rolls, R. J., Growns, I. O., Khan, T. A., Wilson, G. G., Ellison, T. L., Prior, A. and Waring, C. C. (2013).
Fish recruitment in rivers with modified discharge depends on the interacting effects of flow
and thermal regimes. Freshwater Biology, 58, pp. 1804-1819.
Torrible, L., Sainty, G. and Horcroft, D. (2009). Assessment of the Water Dependent Vegetation
and Fauna of the Mallowa Creek, results from a field visit Feb 2009. IRPEC Pty Ltd.
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Wilson, G. G., Bickel, T. O., Berney, P. J. and Sisson, J. L. (2009). Managing environmental flows in
an agricultural landscape: the Lower Gwydir floodplain. Final Report to the Commonwealth
Department of Environment, Water, Heritage and the Arts.
37