Post on 21-Aug-2020
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QUARTERLY OUTCOMES NEWSLETTER | JANUARY– MARCH 2020
LACHLAN RIVER MONITORING, EVALUATION AND RESEARCH
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LACHLAN RIVER MONITORING, EVALUATION AND RESEARCH
Welcome to the March 2020 quarterly newsletter of the Lachlan Monitoring, Evaluation and
Research (MER) Program. This newsletter forms part of the reporting activities undertaken in
the Lachlan river system under the MER Program and provides a regular update on our moni-
toring activities and observations.
In this issue we put a spotlight on our fish community monitoring which occurs each year in
early Autumn. We then take a look at the weather conditions we’ve experienced in the
catchment during the quarter we well as the volumes that have been flowing down the river.
We provide an update on our fish community monitoring field trip and the progress of our
research project on monitoring reedbeds in the Cumbung Swamp. Finally, in our latest instal-
ment of the Lachlan Diaries, Adam Kerezsy introduces us to one very pretty, small and endan-
gered fish which is found in Brewster Weir Pool.
We hope you enjoy the read!
The Lachlan MER Team
Lake Brewster Weir Pool (Photo: Mal Carnegie)
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INDICATOR SPOTLIGHT
Fish Community Monitoring
Autumn is fish community monitoring time for the
Lachlan MER team. Why autumn? Well most of the
native fish spawn in the second half of the year, so by
the following autumn the offspring are large enough to
be captured using standard fish capture techniques,
but small enough so that they can be identified as
young-of-year.
Juvenile Murray cod
captured in the Lach-
lan River during the
fish community sur-
veys in 2020 (Photo:
DPI Fisheries)
Adult golden
perch being
returned to the
river after measuring during fish community surveys in the
Lachlan River in 2020 (Photos: DPI Fisheries)
Flow plays an important role in the life-cycle of
native fishes from larval through to adult life
stages.
Water may inundate habitat needed to breed, trigger a
spawning response; create a boost in food resources
that improves recruitment success; improve habitat
condition by moving sediment and improving water
quality; or stimulate and facilitate in-stream migration.
Some fish species need certain types of flow to initiate
spawning. For example, research has shown us that
golden perch (Macquaria ambigua) need variable win-
ter-spring flows followed by an increase in river height
combined with water temperatures of more than 19
degrees to spawn. This means that seasonality of the
flow is critically important.
Spawning is just the start of the life-cycle of fish and to
successfully grow to be adult fish, young fish need
food resources which can be provided by nutrients
which are transferred into the river when flows inun-
date banks and floodplains moving leaf litter and other
organic material into the river.
Fish also need good quality habitat and this means
that sediment transport and scouring during high flow
events is essential for maintaining deep pools and con-
tributing woody debris and large wood to the river to
provide habitat. Flushes of fresh water (freshes) also
helps to maintain water quality and provide move-
ment triggers and facilitate longitudinal connectivity
within the system.
For all fish species, access to high quality refugia dur-
ing drought is critically important for survival as, unlike
many other taxa, fish have limited ability to move to
new areas and cannot survive with the loss of habita-
ble water for even very brief periods of time.
Supporting native fish in the Lachlan river system has
been a major focus of environmental water delivery
over the past five years. Environmental water has
been delivered to support fish outcomes, either direct-
ly (through the provision of spawning flows) or indi-
rectly (through improvements to water quality or habi-
tat access) in every year of the program.
What is a fish community?
In ecology, a community is a group or association of
individuals of two or more different species occupy-
ing the same geographical area at the same time. A
healthy fish community is made up of a number of
native fish species, each with juveniles and adults
present. We single out ‘Young-of-year’ as a special
group of juvenile fish that were born within the past
year as they give us information about recent
spawning.
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Monitoring
To monitor fish communities, the team uses elec-
trofishing and netting. Electrofishing uses electrici-
ty to stun fish allowing fish to be captured and
brought aboard for assessment. Electrofishing pos-
es little harm to fish, with most individuals recov-
ering within seconds of being stunned. The team
also uses a variety of nets to capture fish, including
collapsible bait traps and fyke nets. Once captured,
fish are identified, measured for length and weight
and returned to the river.
Data collected from the fish community monitor-
ing program provides an assessment of the health
of the fish community and provides a robust da-
taset to detect change in response to environmen-
tal flow releases over time. Critical components
assessed as part of MER relate to recruitment
(how many young-of-year individuals there are)
and native species composition compared to alien
species.
DPI Fisheries electrofishing boat (Photo: DPI Fisheries)
Monitoring results under LTIM and MER since
2015 indicated that there are fluctuations in fish
community composition in the Lachlan River with
flow, particularly in relation to the large floods in
2016/2017. The number of adult Murray cod cap-
tured during sampling in the Lachlan River de-
creased following this flooding, likely because of
the subsequent blackwater related mortality.
Numbers of Murray cod caught per site in the fish com-
munity monitoring undertaken during the LTIM program
The team has also detected the threatened fresh-
water catfish while monitoring, which is a good
sign that this species is holding on in this reach.
This is supported by other sampling higher in the
catchment, where catfish have been sampled at
four off-river creeks and wetlands. The team has
yet to detect natural recruitment of golden perch
in the lower Lachlan River, despite some efforts to
create favourable spawning conditions using envi-
ronmental water. Facilitating natural golden perch
recruitment in the catchment is under considera-
tion for future years.
What about carp?
The delivery of environmental water in warmer months to support native fish species runs the risk of pro-
moting a common carp spawning event, particularly if wetlands are inundated. In the Lachlan river system,
the use of Commonwealth environmental water has generally been confined to in-channel flows. This was a
successful approach in 2014-15, 2017-18 and 2018-19 with low levels of common carp spawning detected in
these years and minimising connections with wetlands during warmer months remains a strategy to be used
within the catchment.
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Catchment conditions January to
March 2020
Rainfall across the catchment had been well below
average since June 2019, but in the first quarter of
2020 the conditions became wetter. February and
March were the wetter of the three months, with
41.4 mm falling at Hillston in February and 68.6
mm falling in March. The majority of the March
rainfall fell in one big event with 54.2 mm on the
5th of March. The total rainfall amount for this
quarter was 133.6 mm surpassing the long term
median rainfall which is only 49.6 mm.
Average daily maximum and minimum tempera-
tures at Hillston for the first quarter of 2020 were
slightly below average. January was an exception,
was the warmest, with a highest daily maximum at
46 degrees and an average temperature of 35.6
degrees which is 2 degrees warmer than the long-
term average.
These daytime temperatures were accompanied by
minimums for this quarter that were equal to the
long-term averages.
Graphs showing rainfall and maximum and minimum
temperatures for the first quarter of 2020. Data are for
the weather station number 075032 and are sourced
from the Bureau of Meteorology.
OBSERVATIONS AND OUTCOMES
What is median rainfall?
Median rainfall is the mid-point of all observed rainfall records when they are sorted in
order of magnitude (from the lowest to the highest). The median is the preferred measure
of 'typical' rainfall from a meteorological point of view. This is because of the high varia-
bility of rainfall; one extreme rainfall event will have less effect on the median than it will
have on the average.
For more information see: http://www.bom.gov.au/climate/cdo/about/about-stats.shtml
Conditions became wetter
in the first quarter of 2020
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Hydrology
The four watering actions using Commonwealth environmental water for 2019-20 were delivered be-
tween October and December 2019. The peak of the spring pulse occurred in mid October at Willandra
Weir at just under 1100 ML/day. The peak of the spring pulse took almost 4 weeks to reach the edge of
the Great Cumbung at Four Mile. By the time it reached Four Mile, the spring pulse had become attenu-
ated—this means that the peak flows were lower (only 330 ML/day) and the pulse was almost twice as
long (occurring over 6 weeks instead of 3 weeks).
OBSERVATIONS AND OUTCOMES
Hydrographs showing flow in the Lachlan River downstream of Willandra Weir and at the edge of the Great Cumbung. Com-
monwealth environmental water spring pulse is shaded green. Data from Water NSW (http://waterinfo.nsw.gov.au/).
Water from the spring pulse which delivered water to the Great Cumbung in November, peaked in late
November and had fully receded by the 1st January.
Sentinel imaging showing water (false colour
blue) in the Great Cumbung on the 5th De-
cember 2019 (above) and the 1st January
2020 (right)
Further information about the watering actions can be found at:
http://www.environment.gov.au/water/cewo/catchment/lachlan/water-use
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Fish community monitoring
University of Canberra and NSW DPI Fisheries staff
recently completed annual fish community surveys
between Wallanthery and Hillston. A range of spe-
cies were captured (and returned to the water after
being measured), including a number of large Mur-
ray cod and reasonable numbers of young Murray
cod (new recruits). The team also caught numer-
ous 40-50 cm golden perch and a range of other
native fish species including bony herring, carp
gudgeon, Australian smelt, flatheaded gudgeon and
unspecked hardyhead.
OBSERVATIONS AND OUTCOMES
Bony herring caught during fish community surveys in
the Lachlan River in 2020. (Photo: NSW DPI Fisheries)
Sentinel imaging showing water (false colour
blue) in the Great Cumbung on the 5th De-
cember 2019 (above and the 1st January 2020
(right)
Flatheaded gudgeon caught during fish
community surveys in the Lachlan River in
2020. (Photo: NSW DPI Fisheries)
The Lachlan River at Hunthawang, one of the regular fish monitoring sites (Photo: Ben Broadhurst)
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Research
The University of Canberra, Centre for Applied Wa-
ter Science team has been conducting research to
develop techniques to monitor the response of
reedbeds to environmental water. As part of this
research we have undertaken four field trips over
Spring and Summer (2019-20) monitoring the
reedbed of the Great Cumbung Swamp. During
these trips we have collected a range of data
through on-ground monitoring and the use of
drone imagery.
The reedbed of the Great Cumbung Swamp, domi-
nated by the reed species Phragmites australis or
common reed, is the largest stand of common
reed in NSW, and provides important habitat for a
range of bird species, particularly in periods of
drought. Within the Great Cumbung Swamp, thick
patches of common reed occur along the main
channel of the Lachlan River and surrounding low-
er lying open marsh lakes. These open marsh lakes
intermittently connect with the Lachlan River
channel during high-flow events, where water
floods across the swamp before inundating the
surrounding reedbeds depending on the magni-
tude of inundation.
Common reed is a species of grass (Poaceae)
which primarily grows over the warmer months
(September-April) of the year. New reed shoots
start to grow in late winter/early spring and con-
tinue to grow over summer. During Autumn
shoots start to senesce, kind of like the leaves of a
deciduous tree. These (senescent) brown reeds
will remain on the plant into the next growing sea-
son, while the young green shoots start to grow.
RESEARCH
Location of the Great Cumbung in the Lachlan Catchment
Nest built in the
reeds (Photo: Will
Higgisson) and
healthy looking
reeds (Photo: Matt
Young)
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The once natural flow of the Lachlan River has been
extensively modified by river regulation and extrac-
tion. These changes to river flow patterns have re-
duced the frequency, duration and extent of inun-
dation which now occurs in the Great Cumbung
Swamp. Common reed along with other flood de-
pendent species which occur in the Great Cumbung
Swamp depend on these inundation events to per-
sist in the landscape. For this reason, the reedbeds
of the Great Cumbung Swamp have been targeted
with Commonwealth environmental water to main-
tain the current extent and increase periods of
growth.
The reedbed of the Great Cumbung Swamp re-
ceived Commonwealth environmental water twice
in 2019. The first occurred in July, with the greatest
extent of the Cumbung Swamp inundated on the
2nd July, and the second event occurred in Novem-
ber, with the greatest extent of the Cumbung
Swamp inundated on the 10th November. 2019 was
a particularly dry period in the lower Lachlan Catch-
ment resulting in low river levels apart from the
Commonwealth’s environmental watering actions.
These events inundated the open marsh lakes of
the Great Cumbung Swamp and parts of the sur-
rounding reedbed.
While our team have set out to develop techniques
to monitor reedbeds and their response to environ-
mental water, in the process we have collected val-
uable and interesting data on how reedbeds grow
and their response to flooding. Preliminary analysis
has shown that the environmental watering events
have resulted in increased height of reeds and the
presence of flower heads for sites which received
flooding compared to sites which had not received
flooding which were much smaller and produced no
flower heads. This result demonstrates the im-
portance of flooding to the growth and reproduc-
tion of common reed and the important role of en-
vironmental water during dry periods.
Changes to river flow patterns
have reduced the frequency,
duration and extent of inunda-
tion which now occurs in the
Great Cumbung Swamp.
Environmental water reaches the Great Cumbung—November 2019 (Fiona Dyer)
A developing seed head (Photo: Will Higgisson)
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Stories from monitoring and community
events in the Lachlan catchment
Adam Kereszy, fish biologist at large
Olive Perchlet in the Lachlan catchment
Olive perchlet are one of the rarest fish in the
Lachlan, and are currently found in only one
location – upstream of a weir, halfway be-
tween Lake Cargelligo and Hillston.
The rare olive perchlet, currently known from a single
population in the Lachlan catchment (Photo: Adam Ke-
rezsy)
Olive perchlet belong to a family called Ambas-
sidae that are collectively referred to as
‘glassfish’ because of their translucent bodies.
There are several species that occur in north-
ern and central Australia, and also in New
Guinea, but the species in question here – Am-
bassis agassizii – although common in coastal
rivers on the eastern seaboard, appears to
have declined in the Murray-Darling Basin in
the time since Anglo-European colonisation
and associated river regulation. Their common
name gives an indication of their stature: they
are a perch, like much bigger distant relatives
like cod and yellowbelly, but they are consid-
ered massive at 50 mm and old at two years,
so ‘perchlet’ is very appropriate.
It’s difficult to pinpoint reasons why olive per-
chlet are rare. Along the coast, the species ap-
pears to compete successfully alongside alien
fish like live-bearing guppies and their relatives
(such as platys, swordtails and gambusia). In
the rivers of far western Queensland like the
Cooper and Diamantina, a closely-related spe-
cies is mostly present and booms after floods.
In other words, fickle rivers and a fair amount
of competition don’t seem to be limiting fac-
tors to the success of the species in other plac-
es, and it’s reasonable to assume – as many
fish ecologists do – that olive perchlet used to
be more widespread and abundant in the me-
andering rivers of the MDB.
As with many MDB species, it seems likely that
the combination of negative factors has con-
tributed to the apparent decline. River regula-
tion disrupted flows and breeding cues and
cycles. Barriers like dams and weirs prevented
up and downstream migration. Following the
carp explosion, in-stream vegetation – a fa-
voured habitat – diminished, and introduced
predators like redfin perch would almost cer-
tainly enjoy a mouthful of olive perchlet when
the opportunity presented itself.
THE LACHLAN DIARIES
Olive perchlet are one of the
rarest fish in the Lachlan,
found only in one location.
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But all that said, we really don’t know. This is
because – unfortunately – by the time we col-
lectively started working out what did and did-
n’t live in the MDB, the rivers were already
compromised. You could say the horse had al-
ready bolted.
What we do know is that we still have at least
one population of olive perchlet in the Lachlan,
so it’s likely they are more widespread, it’s just
that we haven’t found them yet. Even so, this
population is not always easy to find. They are
mostly present, but there have been a couple
of sampling trips in the last few years that
failed to detect them.
In mid-March 2020, two members from ANGFA
– the Australia and New Guinea Fishes Associa-
tion – travelled to the weir pool with their small
box traps and dip nets to assist DPI Fisheries
and State and Commonwealth environmental
water managers (DPIE–EES and CEWO) gauge
the status of the Lachlan River olive perchlet
population. The timing was important given the
recent water shortages within the catchment.
As Commonwealth and NSW environmental
water has been (and will continue to be) used
to assist the olive perchlets through drought, I
went along with a set of funnel-shaped fyke
nets at the request of the Lachlan environmen-
tal water manager to conduct a formal popula-
tion and habitat assessment.
ANGFA members are a diverse group, but they
all have one thing in common: they absolutely
love fish. As soon as I arrived, I remembered
NSW President David Matheson from talks I
had given at ANGFA meetings in the past. His
accomplice this time was Lachlan Nevinson, a
fish-obsessed shearer from Holbrook. Dave and
Lachy had already done a bit of fishing and had
already found a few olive perchlet and other
local native species, but they were extremely
keen to pull on their waders and head out to
set the bigger fyke nets and see what turned up
overnight.
We still have at least one popu-
lation of olive perchlet in the
Lachlan.
(L-R) Nathan McGrath (DPIE), Dave Matheson and Lachy Nevinson (both ANGFA) set a fyke net during fish sampling in
the mid Lachlan in 2020 (Photo: Adam Kerezsy)
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Setting and retrieving nets and taking samples is
ok by yourself, but the time always passes much
faster when there are like-minded people to
share the work with and chat to: on this trip
there was Dave and Lachy, and also Nathan
McGrath from the DPIE–EES environmental wa-
ter team and carp-fisher Keith Bell, so no prizes
for guessing the general content of the conversa-
tions. In fact, Dave, Lachy and Nathan were so
keen they even went out fishing again long after
the sun had set in order to improve the accuracy
of our species list.
The population of olive perchlet in the MDB is
listed as endangered. Given their rarity this is
probably a good thing, but it presents challenges
for hobbyists/naturalists/conservationists like
Lachy and Dave.
As much as they would love to be directly in-
volved in taking immediate action and breeding
up our endangered species in captivity, there are
complex processes and legislation to be navi-
gated which can dampen some of the enthusi-
asm. This is a bit of a shame, because those of us
who work professionally on fish mostly don’t
have the time, the facilities or – in some cases –
the expertise to care for and breed fish under
captive conditions. We all love fish too – but in a
slightly different way.
As we dragged the nets in the following morning
we were all gratified to find a juvenile olive per-
chlet that was only 17mm long. This meant that
the community in the weir pool had spawned
with at least some success in spring and summer
2019/2020, but we all agreed their future was
still hard to predict. With a bit of luck, people like
Lachy and Dave will stay interested in conserving
our threatened native species, and with a bit
more, hopefully at some stage they may be able
to take a more active role in breeding popula-
tions for re-release in other suitable locations.
The population of olive perchlet in
the MDB is listed as endangered.
The olive perchlet community in
the Brewster weir pool has
spawned with at least some suc-
cess in spring and summer 2019-
2020.
Nets set in Brewster Weir pool (Photo: Joanne Lenehan)
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ACTIVITY SUMMARY
The following summary provides information about the contracted activities undertaken between October and
December 2019 as part of the Lachlan Monitoring, Evaluation and Research (Lachlan MER) Project. Activities that
will be undertaken between January and March 2020 are listed as upcoming activities.
ACTIVITIES PROGRESS TO DATE UPCOMING ACTIVITIES
Monitoring activities
Ecosystem type Data collection complete and suggested Australi-an National Aquatic Ecosystems (ANAE) types for all sites included in the Monitoring and Data Management System (MDMS).
No more data collection required
Fish (river) Adult fish community sampling completed in March
Data processing, QA/QC and data entry
Fish (larvae) Larval fish samples processed, data entry and analysis commenced
Data entry continuing
Water quality and stream metabolism
Data processing commenced Downloading and servicing loggers if possible
Vegetation diversity Data processing commenced Data processing, QA/QC and data entry
Evaluation activities
Monitoring data entry Data entry continuing Data entry continuing
Research activities
Research Two rounds of data collection Commenced data and image processing
Data and image processing Further data collection (if possible) Assessment of sites and data col-
lection to date
Communication and engagement
Selected Area Working Group (EWAG and TAG meetings)
Hay EWAG meeting Online EWAG meeting May
Project team teleconference None Project team teleconference
Other Stakeholder Engage-ment
Robinson Crusoe Island Down the Track Weekend Robinson Crusoe Island Down the Track Weekend
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ABOUT THIS DOCUMENT
The Commonwealth Environmental Water Holder (CEWH) is responsible under the Water Act 2007
(Cth) for managing Commonwealth environmental water holdings. These holdings amount to more
than 2,700 gigalitres (as at July 2019) of water entitlements across the Murray-Darling Basin. The hold-
ings must be managed to protect or restore the environmental assets of the Murray-Darling Basin, and
other areas where the Commonwealth holds water, to give effect to relevant international agree-
ments.
Monitoring and evaluation are critical for supporting effective and efficient use of Commonwealth en-
vironmental water. Monitoring and evaluation also provides important information to ensure the
CEWH meet their reporting obligations. Between 2014 and 2019, the Commonwealth Environmental
Water Office (CEWO) has undertaken monitoring and evaluation of the ecological outcomes of envi-
ronmental watering through the Long Term Intervention Monitoring Project (LTIM Project). At the
same time, the CEWO has undertaken research which seeks to improve the science available to sup-
port environmental water management in the Murray-Darling Basin through the Murray-Darling Basin
Environmental Water Knowledge and Research Project (EWKR Project).
The Monitoring, Evaluation and Research Program (MER Program) builds on the work of the LTIM and
EWKR Projects to undertake monitoring, evaluation and research activities within seven Selected Are-
as and at the Basin-scale between 2019 and 2022. One of the seven Selected Areas is in the Lachlan
river system and a team of researchers, agency staff and contractors led by the Centre for Applied Wa-
ter Science at the University of Canberra are monitoring, evaluating and conducting research in the
catchment.
This newsletter forms part of the reporting activities undertaken in the Lachlan river system under the
MER Program. It will be produced quarterly and highlights the activities, observations and outcomes
that have occurred in the river system in relation to environmental water.
In conducting the monitoring evaluation and research project in the Lachlan river system, the project
team as well as the Commonwealth Environmental Water Office respectfully acknowledge the tradi-
tional custodians of the land on which this work is conducted, their Elders past and present, their Na-
tions of the Murray-Darling Basin, and their cultural, social, environmental, spiritual and economic
connection to their lands and waters. The Lachlan River flows through the lands of the Nari Nari,
Ngiyampaa, Waradjuri and Yita Yita Nations, and we acknowledge these people as the traditional own-
ers of the land on which this publication is focused.
More information can be found at:
https://www.environment.gov.au/water/cewo/monitoring/ltim-project
https://www.environment.gov.au/water/cewo/monitoring/ewkr
https://www.environment.gov.au/water/cewo/monitoring/mer-program
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INQUIRIES REGARDING THIS DOCUMENT SHOULD BE ADDRESSED TO:
This document was prepared by Fiona Dyer, Will Higgisson, Ben Broadhurst (CAWS-UC), Jason Thiem and
Daniel Wright (DPI Fisheries) and Adam Kerezsy (Dr Fish).
Cover Photo: Returning an adult Murray cod to the river following capture using electrofishing. (DPI Fisheries)
Document history and status
Distribution of copies
Copyright © Copyright Commonwealth of Australia, 2020
‘Lachlan River, Monitoring, Evaluation and Research, Quarterly Outcomes Newsletter’ is licensed by the Commonwealth of Australia for use under a Creative Commons By Attribution 3.0 Australia licence with the exception of the Coat of Arms of the Commonwealth of Australia, the logo of the agen-cy responsible for publishing the report, content supplied by third parties, and any images depicting people. For licence conditions see: http://creativecommons.org/licenses/by/3.0/au/
Disclaimer
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 and Energy. While reasonable efforts have been made to ensure that the contents of this publication are factually cor-rect, 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.
Version Date Issued Reviewed by Approved by Type
Draft 1 3 April 2020 Project Team Fiona Dyer DRAFT
FINAL 24 April 2020 CEWO Fiona Dyer FINAL
Version Type Issued to
FINAL Electronic Commonwealth Environmental Water Office
Damian McRae
Commonwealth Environmental Water Office
Phone: 02 6274 2524
e-mail: damian.mcrae@environment.gov.au
Dr Fiona Dyer
University of Canberra
Phone: 02 6201 2452
e-mail: Fiona.Dyer@canberra.edu.au