Assessment of environmental water requirements for the ...

clipperstastefulManagement

Nov 9, 2013 (3 years and 7 months ago)

118 views





Published by Murray
-
Darling Basin Authority

Postal Address GPO Box 1801, Canberra ACT 2601

Office location Level 4, 51
Allara Street, Canberra City

Australian Capital Territory

For further information contact the Murray
-
Darling Basin Authority office

Telephone (02) 6279 0100 international + 61 2 6279 0100

Facsimile (02) 6248 8053 international + 61 2 6248 8053

E
-
Mail info
@mdba.gov.au

Internet
http://www.mdba.gov.au


MDBA Publication No
:

2
4
/12

ISBN
:

978
-
1
-
922068
-
3
2
-
3

(online)


© Murray

Darling Basin Authority for and on

behalf of the Commonwealth of
Australia,
2012.

With the exception
of the Commonwealth Coat of Arms, the MDBA logo, all photographs,
graphics and trademarks, this publication is provided under a Creative Commons Attribution
3.0 Australia Licence.


http://creativecommons.org/licenses/by/3.0/au

The MDBA’s preference is th
at you attribute this publication (and any material sourced from
it) using the following wording:

Title:

Assessment of environmental water requiremen
ts for the proposed Basin Plan:
Lower Balonne Floodplain

Source:

Licensed from the Murray

Darling Basin Au
thority, under a Creative Commons
Attribution 3.0 Australia Licence.

The MDBA provides this information in good faith but to the extent permitted by law, the
MDBA and the Commonwealth exclude all liability for adverse consequences arising directly
or indir
ectly from using any information or material contained within this publication.

Australian Government Departments and Agencies are required by the
Disability
Discrimination Act

1992 (Cth) to ensure that information and services can
be accessed by
people with disabilities. If you encounter accessibility difficulties or the information you
require is in a format that you cannot access, please contact u
s.

1


Condamine
-
Balonne Region


Assessment of the
Lower Balonne
River
Floodplain

System
e
nvironmental
w
ater
r
equirements

1.

Introduction

The Water Act 2007 (Cwlth) established the Murray‐Darling Basin Authority (MDBA) and tasked it
with the preparation of a Basin Plan to provide for the integrated management of the Basin’s water
resources. One of the key requirements of the Basin Plan is to

establish environmentally sustainable
limits on the quantities of surface water that may be taken
for

consumptive use
, termed Sustainable
Diversion Limits (SDLs)
.

SDLs

are the maximum long‐term annual average
volume
s of water that can
be taken from
the Ba
sin and they must represent an

Environmentally Sustainable

Level of Take
(ESLT).


The method used to determine the ESLT is described in detail within


The propose
d

environmentally

sustainable level of take” for surface water of the Murray
-
Darling Basin: Method
and Outcomes,’
(MDBA

2011).
A summary of the main steps undertaken to determine the ESLT is
presented in
Figure 1. The
assessment
of environmental water requirements
includin
g specification
of site
-
specific flow indicators

at a subset of hydrologic indicator sites
(
Step 3 of the overall ESLT
method
) is the focus of this document.

The work described herein is the MDBA’s current understanding of the environmental water
requireme
nts of
the
Lower Balonne Floodplain
. It is not expected that the assessed environmental
water requirements assessments will remain static, rather it is intended that they will evolve over
time in response to new knowledge gained through additional scientif
ic research or implementation
of environmental watering actions. Within this context, feedback is sought on the material
presented within this document whether that be as part of the formal draft Basin Plan consultation
phase or during the environmental wa
tering implementation phase within the framework of the
Environmental Watering Plan.

1.1.

Method to determine site
-
specific flow indicators

Assessment of environmental water requirements
for different elements of the flow regime
using
the hydrologic indicator
site approach is one of the key lines of evidence that has informed the
proposed SDLs.

Effort

focussed on regions and parts of the flow regime with greatest sensitivity to
the scale of reduction in diversions necessary to achieve environmental objectives,
an ESLT and a
healthy working Basin.

Within the overall framework of the ESLT method

(Figure 1) the MDBA used an iterative process to
assess environmental water requirements and develop
site
-
specific flow indicators.

The hydrologic indicator site approach

uses

d
etailed
eco
-
hydrological
assessment
of
environmental
water requirements

for a subset of the key environmental assets and key ecosystem functions
across the Basin.
The
Lower Balonne Floodplain

is one of the key environmental assets where a
detailed assessment of environmental water requirements was undertaken.


2



Figure 1:
Outline of method used to determine
an

Environmentally Sustainable Level of Take
.

(
Source:
MDBA 2011)
.

D
etailed
environment
al water requirement
assessments lead to the specification of s
ite
-
specific
flow indicators

to achieve site
-
specific ecological targets. Flow indicators were expressed at a
hydrologic indicator site

or sites.
Environmental water requirements specified at
h
ydrologic
indicator sites
are intended to
represent the broader environmental flow needs of river valleys or
reaches

and thus the needs of a broader suite of assets and functions.

This report provides a description of the
detailed eco
-
hydrological assessme
nt of environmental
water requirements for the
Lower Balonne Floodplain

including information supporting the
development of site
-
specific flow indicators for the site (with reference to flows gauged on the

Culgoa

River).
More information on how the site
-
sp
ecific flow indicators for
Lower Balonne
Floodplain

were used within the Basin
-
wide modelling process to inform the ESLT (i.e. Step 5 and 6

3


in Figure 1) can be found in the report

Hydrologic modelling to inform the proposed Basin Plan:
Methods and results

(MDBA 2012)
.

A d
escription of the
detailed eco
-
hydrological assessments of environmental water requirements
for other indicator sites are described in other documents in the series ‘
Assessment of
environmental water requirements for the proposed Basin Pl
an
’.

1.2.

Scope and purpose for

setting
site
-
specific flow indicators

The
MDBA’s
assessment of environmental water requirements and
associated

site
-
specific flow
indicators at hydrologic indicator sites has been used to inform the development of SDLs. This
enab
les the MDBA to estimate the amount of water that will be required by the environment over
the long
-
term to achieve a healthy working Basin

through the use of hydrological models
.
Accordingly
, site
-
specific flow indicators are not intended to stipulate
fut
ure use of

environmental
water
.
MDBA expects that the body of work undertaken to establish
these site
-
specific flow
indicators
will

provide valuable input to environmental watering but this watering will be a flexible
and adaptive

process guided by the fra
mework of the Environmental Watering Plan
. It will be up to
the managers of environmental water, such as the Commonwealth Environmental Water Holder,
State Government agencies, and local communities to decide how best to use the available
environmental wat
er during any one year to achieve environmental outcomes.

2.

Site
location and extent

The
Lower Balonne Floodplain

hydrologic indicator site
covers approximately 1
,
988
,
0
00

ha

(
Sims
and

Thoms 2002
). The Lower Balonne system
is a distributary
r
iver network that
extends from St
George in Queensland to the Barwon River in northern New South Wales

(
Figure
2
)
.

The Balonne
River divides into five separate channels. The Culgoa and Narran
R
ivers are the main channels,
conveying 35% and 28% of the long
-
term mean annual flow at St George respectively; while the
Ballandool and Bokhara Rivers and Birrie Creek flow only during higher discharge periods (Thoms et
al. 200
2
)

(Figure 2)
.

Approximately 30%

of the system

is in Queensland and 70%

in New South Wales
(
McCosker 1996
).

The
MDBA

has used
the wetlands
geographic information systems
of the Murray
-
Darling Basin
series 2.0 (
Kingsford
, Thomas
and

Knowles

1999
) to defi
ne the lateral and downstream
extents of
the asset.
D
ata from
A

d
irectory of
i
mportant
w
etlands in Australia

(
Department of the
Environment, Water, Heritage and the Arts 2001
)
was used to determine the upstream extent of the
asset
at
Jack Taylor
Weir
.


The Narran Lakes is
the terminal wetland system at the end of the Narran River, which is located on
the eastern extent of the
Lower Balonne Floodplain
.

The

floodplain immediately surrounding
the
Narran Lake
s

system
was not included in the extent of this
asset

and is considere
d a hydrologic
indicator site in its own right (
see
s
eparate
environmental water requirements report for

Narran
Lakes
)
.


4



Figure 2

Location and extent of
Lower Balonne
River
Floodplain

System
hydrologic indicator site


5


3.

Ecological

Values

Land

use on the
Lower Balonne Floodplain

is predominantly grazing and
dryland and
irrigated
cropping.
There are two national parks on the Lower Balonne floodplain: the 22,430

ha Culgoa
National Park, managed by NSW National Parks and Wil
dlife Service, and the adjoining 42,800

ha
Culgoa Floodplain National Park, managed by Queensland National Parks and Wildlife Service
(CSIRO 2008).

The vegetation community composition of the
Lower Balonne Floodplain

varies across the
floodplain according
to flood frequency (Sims and Thoms 2002). High flood frequency areas are
dominated by river red gum (
Eucalyptus camaldulensis
), coolibah (
E. coolabah
) and lignum
(
Muehlenbeckia florulenta
)
,
and
open grasslands dominat
e

less frequently flooded areas (Sims and
Thoms 2002; Sims 2004). The extents of major
vegetation communities found i
n the section of the
Lower Balonne Floodplain

between

Hebel on the state border
and

St.

George approximately 110 km
to the north
-
east

are sh
own
in Table 1
.


Table 1

Key Vegetation Communities of the Queensland Section of the
Lower Balonne
Floodplain

(adapted from Sims 2004)

Vegetation
Community
Functional
Group

Extent
(
ha
)

Key Species

Trees/Overstorey


(cover %)

Shrub Layer

(cover %)

Ground Layer

(cover %)

Riparian
Forest

11,588

E. camaldulensis, E.coolabah,

E. populnea,

C
asuarina

cristata, Melaleuca
s
p
p.

(70%)

Acacia spp,

M. florulenta

(15%)

Sporobolus

mitchelli,
Cyperus

bifax,
Eragrostis

setifolia,

Ptilotus exaltatus

(
15%
)

Lignum

shrubland

45,234

E. cool
a
bah,

A
cacia

cambagei

(15%)

M. florulenta

(70%)

S
.

mitchelli, C. bifax

(15%)

Coolibah
Woodland

52,087

E
.

cool
a
bah,

E. populnea, A
.
cambagei

(40%)

M. florulenta

(20%)

C. bifax, Eliocharis spp., Eragrostis spp.

(
20%)

Nutgrass

33,526

E. populnea

(
10%
)

M. florulenta

(20%)

C. bifax, Eliocharis spp., Aristida spp.

(65%)

Open
Grassland

101,882

-

M
.
florulenta

(10%)

Astrebla lappacea, Bassia spp,

Cenchrus ciliaris,

Marsilea drummondii,

E
.
setifolia, Paspalidium

jubiflorum
,
C
.

bifax, Plantago

spp, Medicago spp, P. jubiflorum

(70%
-

seasonal)


6


In order to inform Park management activities
,

floristic surveys and associated vegetation mapping
was undertaken across the Culgoa National Park.
Surveys undertaken in February 1999 identified six
distinct communities with
c
oolibah (
Eucalyptus cool
a
bah
)/
r
iver
c
ooba

(
Acacia stenophylla
) and

c
oolibah/
w
eeping
m
yall
(Acacia pendula)

w
oodlands covering over 70
% of the park (Hunter 2005
).
Hunter also note
s

that the Park includes expanses of
l
ignum (
Muehlenbecki
a

florulenta
).


These ecosystems support important species that are listed in international agreements such as
the
Ramsar

Convention
, and include vulnerable and endangered species. Appendix B
provides a
summary of the conservationally significant species recorded at the site.

The
ecological
value
s

of the floodplain
are

reflected in
MDBA’s assessment

against the criteria used
to identify key environmental assets within the Basin. The MDBA estab
lished five criteria

to identify
important environmental
assets

in the Basin
.

The criteria
broad
ly

align with the National Framework
and Guidance for Describing the Ecological Character of Australian Ramsar Wetlands (Department
of the Environment, Water, H
eritage and the Arts 2008) and the draft criteria for identifying High
Conservation Value Aquatic Ecosystems (SKM 2007).

Based on the

ecological
values

identified
on the
Lower Balonne Floodplain
, the site

meets
at least
three of the

five criteria

(
see
Tabl
e
2
).





7


Table
2

Assessment of the Lower Balonne
River
Floodplain
System
against MDBA key
environmental asset criteria.

Criterion

Ecological values that support the criterion

2
.

The water
-
dependent
ecosystem is natural or
near
-
natural, rare or unique

The
Lower Balonne Floodplain

is a unique water
-
dependent ecosystem, as the floodplains of
the Culgoa, Birrie, Bokhara and Narran
R
ivers support the largest area of native grasslands in
New South Wales (Dick 1993). It is also unique as the coolibah (
Eucalyp
tus coolabah
)
woodlands in the Lower Balonne are some of the most extensive and contiguous communities
remaining (Whittington et al. 2002).

Various types of Coolibah Woodlands are commonly found throughout the Culgoa National
Park (Hunter 2005) with areas
of C
oo
libah


Black Box (
Eucalyptus largiflorens)
woodland
being particularly significant (NSW Scientific Committee 2011).

The floodplains
can

be considered near
-
natural as they have only 8.5% exotic vegetation, one
of the lowest records of introduced sp
ecies in the Murray

Darling Basin (Dick 1993).

The Lower Balonne
F
loodplain wetland complex is a unique water
-
dependent ecosystem as
the region supports the

second

largest number of wetlands greater than 5

ha in size within the
Murray

Darling Basin. More t
han 3,400 wetlands have been identified within this complex, the
majority of which are freshwater wetlands

(25.8%)

and
floodplain areas (
24.2
%)

(
Thoms et al.
2002)
. This floodplain ecosystem is sustained by water, sediments and nutrients from the
upstream Condamine

Balonne catchment, which comprises 14% of the Murray

Darling Basin
(Rayburg
and

Thoms 2008).

3
.

The water
-
dependent
ecosystem provides vital
habitat

The natural drainage system of the
L
ower Balonne provides diverse habitat for fauna. Fauna
present in the Lower Balonne

F
loodplain
are

included within the Lowland Darling River
aquatic ecological community, which is considered threatened under the
Fisheri
es
Management Act 1994

(NSW), as listed in Appendix B. The habitat preferences of the
endangered aquatic species found within the
Lower Balonne Floodplain

have been
summarised by Smith et al. (2006).

4
.

Water
-
dependent
ecosystems that support
Commonwealth, State or
Territory listed threatened
species or communities

The
Lower Balonne Floodplain

meets this criterion because it supports species listed as
threatened under state or federal legislation
. Of

particular note is the
Coolibah
-
Black Box of
the northern riverine plains in the Darling Riverine Plains and Brigalow Belt South bioregions
.

As part of its assessment of the significance of
Coolibah
-
Black Box of the northern riverine
plains in the Darling Riverine Plains and Brigalow Belt South bioregions
, the NSW Scientific

Committee

found that the dist
ribution of the community had been reduced by 61% (NSW
Scientific Committee 2011). As noted by the Committee, the structure of this community may
vary from tall riparian woodlands to very open grassy woodlands and consist of a wide variety
of species. Base
d on 19 separate findings
,

the NSW Scientific Committee (2011) recognised
the value of the community and maintained its listing as an endangered ecological community
under the
Threatened Species Conservation Act 1995
.

Species and communities listed as th
reatened under both Commonwealth and state legislation
that have been recorded at the site are in
Appendix B
.


8


4.

Hydrology

The Lower Balonne is a complex floodplain channel system

that is
heavily dissected by well
-
defined
channels of various sizes. During
flood events these channels carry a significant proportion of the
‘overland’ flow (
Thoms et al. 2002
). The

Balonne River enters the floodplain downstream of
Beardmore Dam, flowing through St George and over Jack Taylor Weir. It then travels
more

than
70

km before splitting into the Culgoa and Balonne Minor
R
ivers
at the so
-
called ‘first bifurcation’.
Downstream, the
Balonne Minor River

subdivides further to form
four

identifiable streams


the
Narran, Bokhara
,
Ballandool
and Birrie
Rivers
.

The hydraulics

of the Lower Balonne resembles that of a delta, with flows of up to 30,000

ML/d
at
St. George
dispersing into many small flood channels

(
Thoms et al. 2002)
. At higher flows, water
spreads out over the floodplain
,
and a significant portion does not return
to the river as a result of
evaporation and infiltration into the soil. Consequently,
under without
-
development conditions,
the
flow crossing the Queensland



New South Wales border is lower than the flow recorded at
St

George. The median annual flow

at St

George is 1,300

G
L
,

but flows are highly variable. The
maximum annual recorded flow of 8,000

G
L occurred in 1954

55, but extended periods of no
-
flow
occur during droughts.
Based on recorded flows, t
he record period of no
-
flow exceeds 600
consecutive days
(
NSW Western Catchment Authority 2006
).

Floodwaters
received
in the
Balonne River
result from r
ainfall in the northern part of the
Condamine

Balonne catchment
and occur mainly in summer and autumn

(
NSW National Parks
and

Wildlife Service 2003
).

Flood frequ
ency is highly variable, occurring
anywhere
between
several
times a year to
once every five years

(
Sheldon et al. 2000
)
.

The depth of the
floodwater
var
ies

from
a few c
entimetres

to
10
m
etres

and inundation of the floodplain can last for up to

four
months
(
Smith et al. 2006
). During

floods, large amounts of sediment are trapped or deposited onto the
floodplain (Smith
et al.

200
6
). The main river channels in the Lower Balonne system are very
unstable
and
small changes to the flow can result in significant ch
anges in channel morphology
(Smith
et al.

200
6
). Sediment movement has increased with the increase in management
infrastructure in the upper
catchment (
Cullen, Marchant

and

Mein

2003).

The historical flow record suggests that multiple flood events have bee
n common over a yearly
timeframe (
see for example
Figure
3
). The occurrence of multiple events of a similar threshold in
close proximity are important in this system for extending the duration of floodplain inundation,
something
to which
the flora and faun
a of these systems has become
adapted (
Roberts
and

Mars
ton

2000).



9


Figure
3

Highly variable flows
past

St George gauge, Balonne River

The
Lower Balonne Floodplain

has been grazed since the 1840s
(
Sims et al. 1999
),

predominantly by
cattle and sheep.
The
change
to

irrigated agriculture
since the 1990s
represents a significant shift in
land
-
use practice and use of water resources (
T
homs et al. 2002
)
. The major irrigated crop is cotton
,

with
cropped area increas
ing

significantly since 1988
. Associated with t
his expansion in the cotton
industry

has been
the
expansion
of private

water storage
s

on the floodplain over the same period
.

The construction of public storages in the mid and upper sections of the system has resulted in a
degree of regulation, particular
ly of the Balonne River downstream of the Beardmore Dam.
However the systems major public storages and weirs have a combined capacity of 234 GL (CSIRO
2008) and when compared to average surface water availability (1305 GL/year) (CSIRO 2008), their
capacity

to regulate flows is relatively low compared to other parts of the Basin. It is important to
note that within the Condamine
-
Balonne system irrigation water is primarily retained in on
-
farm
private storages; with these storages holding
approximately
seven
times the total volume of public
storages.

5.

Determining the site
-
specific flow indicators for the
Lower
Balonne

River

F
loodplain

System

5.1.

Setting
site
-
specific ecological
targets

The objective setting framework used to determine the ESLT is

outlined in the report

The proposed
“environmentally sustainable level of take” for surface water of the Murray
-
Darling Basin: Method
and Outcomes


(MDBA 2011).

In summary
,
the MDBA developed

a set of Basin
-
wide environmental
objectives and ecological ta
rgets, which were then applied at a finer scale to develop site
-
specific
objectives for individual key environmental assets. Using these site
-
specific objectives
, ecological
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
50,000
1/11/1938
1/12/1938
1/01/1939
1/02/1939
1/03/1939
1/04/1939
1/05/1939
1/06/1939
1/07/1939
1/08/1939
1/09/1939
1/10/1939
1/11/1939
1/12/1939
1/01/1940
1/02/1940
1/03/1940
1/04/1940
1/05/1940
River flow (ML/d)

Date


10


targets that relate specifically to the
Lower Balonne Floodplain

were developed (T
able 3).
Information underpinning site
-
specific ecological targets is shown in Table 3
.

Site
-
specific ecological targets formed the basis of an assessment of environmental water
requirements and the subsequent determination of site
-
specific flow indicators

for the
Lower
Balonne Floodplain
, as described below.


5.2.

Information used to determine s
ite
-
specific flow indicators

The
site
-
specific flow indicators have been determined through
a synthesis of current literature

(including studies cited in Table 3)

and MD
BA
’s

analysis of modelled flow data, in addition to
consultation with state government staff and research providers
. The following sections provide a
summary of the knowledge used to develop the flow indicators.

5.2.1.

Vegetation

Flow thresholds

Whittington et al. (2002), Sims and Thoms (2002), and Sims (2004) provide information on the flow
thresholds used to inform the ecological target associated with ensuring the current extent of
native vegetation of the riparian
,

floodplain

and wetland

commu
nities is sustained in a healthy,
dynamic and resilient condition within the
Lower Balonne Floodplain
. This information is also used
to

address the ecological target concerning the provision of a flow regime which supports key
ecosystem function related to

connectivity between the Balonne, Culgoa, Bokhara, Ballandool,
Birrie and Narran Rivers and the connected floodplain.

Using satellite images captured between September 1989 and April 1999, Sims (2004) analysed
floodplain inundation patterns under a range
of flow conditions for the Queensland portion of the
Lower Balonne floodplain.
Flood magnitudes required to inundate different areas of the floodplain
were determined based on

gauged flows at St. George 14 days before image capture.
Based on this
analysis
, floodplain inundation commences when flows exceed approximately 26,000 ML/d (Sims
and Thoms 2002; Sims 2004) with f
lows at this level inundating around 12,000 ha or around 3% of
the floodplain.

Flows of between 45,000 ML/d and 65,000 ML/d at St. George
inundate approximately 75,000 ha

(Sims 2004).

Flows between 60,000


65,000 ML/d ensure a significant improvement in connectivity
between the systems rivers and channels and its floodplain
(Sims and Thoms 2002; Sims 2004)
. This
connectivity is important fo
r a range of ecosystem functions such as nutrient and carbon exchange.

Sims (2004) found that in general, vegetation communities grade laterally from riparian forests
adjacent to river channels, to lignum and coolibah open woodland associated with infrequ
ent
inundation, with open grassland dominant in rarely inundated areas on the floodplain fringes.

To connect most of the main channels within the Lower Balonne Floodplain, including Birrie River
and a number of secondary channels, a flow of 26,000

ML/d at

St.George is required (Sims 2004).
The author showed that a flow of around 26,000 ML/d would inundate around 12,000 hectares.
Based on Sims (2004) analysis of vegetation communities, the MDBA has determined that the
12,000 ha would consist mainly of ripar
ian forest dominated by river red gum and coolibah (Tables 1
and 6).



11


Table
3

Site
-
specific

targets

for the
Lower Balonne
River
Floodplain

System

Site
-
specific ecological
targets

Justification of targets



Provide a flow regime
which ensures the current
extent of native vegetation
of the riparian, floodplain
and wetland communities is
sustained in a healthy,
dynamic and resilient
condition



Provide a flow regime
which supports the habitat
requirements of waterbirds



Provide a flow regime
which supports a ra
nge of
native aquatic species (e.g.
fish, frogs, turtles,
invertebrates)



Provide a flow regime
which supports key
ecosystem functions,
particularly those related to
connectivity between the
river and the floodplain


Protecting the water
-
dependent ecosystems and their vital habitat requires
retaining the current state of the wetlands and the surrounding vegetation.

Coolibah


Black Box Woodland of the northern riverine plains in the Darling
Riverine Plains and Brigalo
w Belt South bioregions is listed as Endangered
Ecological Community under the
Threatened Species Conservation Act

1995.
Coolibah is typically the dominant tree species in these woodlands and may occur
in association with a wide range of other species inc
luding
r
iver
c
ooba (
Acacia
stenophylla
),
b
lack
b
ox and
r
iver red gum (NSW Scientific Committee 2011). It is
common for a dense understorey of
l
ignum to also form in these Woodland
communities (Hunter 2005).


Coolibah
-
Black Box Woodland provides habitat features important to a range of
fauna (NSW Scientific Committee 2011). These features include grassy
understorey, patches of thick regenerating
Eucalyptus

saplings and large hollow
bearing trees (NSW Scientific Committ
ee 2011).

The Lower Balonne has high ecological and hydrological connectivity to the
Ramsar
-
listed

Narran Lakes Nature Reserve
which

is as an important site for
colonial waterbird breeding.
The link between waterbird breeding and inundation
of habitat wh
ich provides foraging and nesting opportunities is relatively well
understood. The broader
L
ower Balonne floodplain
is

likely to provide foraging
habitats and in doing so support
s

major bird breeding events in the Narran Lakes
system
.

Key ecosystem functio
ns support fish, birds and invertebrates through habitat
maintenance, energy transfer and facilitating connections between rivers and
floodplains. Overbank flows supply the floodplains with nutrients and sediments
from the river, accelerate the breakdown o
f organic matter and supply water to
disconnected wetlands, billabongs and oxbow lakes. As the floodwaters recede,
the floodplains provide the main river channel with organic matter.

The hydrological connection between watercourses and their associated flo
odplain
provides for the exchange of carbon and nutrients (Thoms 2003). The connections
are considered essential for the functioning and integrity of floodplain
-
river
ecosystems.

The maintenance of natural patterns of longitudinal and lateral connectivity
is
essential to the viability of populations of many
aquatic

species (Bunn and
Arthington 2002).

Vital habitat within the Lower Balonne includes in
-
channel
waterholes and billabongs that act as refugia during drought. The use of drought
refugia by aquatic
organisms is often the key to the survival

of
population stocks
and strongly influences the capacity of populations to recover when the drought
breaks and connectivity is restored
, such as
endangered fish and invertebrate
species

(Lake 2003).




12


The flow
thresholds of 45,000 ML/d and 70,000 ML/d at the St George gauge were selected to
provide a flow regime able to inundate lignum and coolibah communities. Hunter (2005) found that
major changes in native vegetation composition across the Culgoa National Par
k were correlated to
flood frequency and the period of inundation. In particular
,

Hunter (2005) found that the ability for
certain sections of the floodplain to retain water for
an
extended period was an important feature
in determining vegetation patterns
.
Based on this observation, t
he MDBA has assumed that areas
which

are flooded regularly and retain water for extended periods contain high proportions of
lignum and river cooba

which are more flood dependent
, while areas which do not retain water are
like
ly to contain less flood dependent species

like
coolibah
. The MDBA has
concluded

flows of both
45,000 ML/d and 70,000 ML/d at the St George gauge are required to inundate areas that retain
water for extended periods

for the different vegetation communities
.

At the lower end of 45,000 to 70,000 ML/d range the three main flood
-
dependent vegetation
communities (coolibah open woodland, lignum and riparian forests) have at least 50% of their total
area wetted (Whittington et al. 2002). A threshold of 70,000

ML
/d encompasses an important
transition in floodplain inundation where floodwaters emerge from the Culgoa River and travel
across the floodplain to re
-
enter the Culgoa downstream, enabling a substantial exchange of
material between the floodplain and its ad
joining aquatic ecosystems (Sims 2004). Around this
threshold is the point where inundation patterns go from being relatively disconnected into a more
highly integrated network of patches (Sims 2004) where approximately 40% of the total floodplain is
inund
ated (Whittington et al. 2002).

The largest flow threshold adopted for the
Lower Balonne Floodplain

i
s a flow of 120,000ML/d at
the St George gauge for one day. At this threshold, around 70% of the floodplain between St

George
and the New South Wales


Queensland border is inundated, with flows greater than this resulting
in proportionally larger increase
s in flow depth rather than increases in floodplain area inundated
(Whittington et al. 2002). Therefore, this flow provides a
balance

between the flood event
magnitude and floodplain area inundated.

The key thresholds presented by Whittington et al. (2002)
, Sims and Thoms (2002)
,

and Sims (2004)
are described at the St George gauge, which is the closest upstream gauge from the
Lower Balonne
Floodplain

(above the first bifurcation). Flows suggested at this gauge therefore take account of the
total amount of
flow entering the
Lower Balonne Floodplain
. However, a large proportion of
diversions

under
Condamine and Balonn
e Resource Operations Plan

occur downstream of St.
George (almost 40% of all diversions within the Queensland section of the Condamine
-
Balonne
s
ystem occur downstream of Jack Taylor Weir).
The gauge
located downstream of St. George at
Brenda on the Culgoa River
more accurately reflects the full impact of diversion
s

and for this reason
this gauge has been selected as a better location to
assess and

specify

proposed environmental
water requirements.

To relate the
key
floodplain vegetation community flow thresholds associated with flows at St
George to flows on the Culgoa River at Brenda, MDBA undertook a correlation analysis o
f

modelled
without
-
devel
opment flow data for the period 1895

2009 (Figure
4
). The analysis compared
modelled peak flows at Brenda and St. George
based on a
n

8 day
flow lag between the two sites.
The analysis focused on flows in the target range of 26,000


120,000 ML/d at St. Geo
rge and so the
range encompasses the inundation threshold as indicated by Whittington et al. (2002).
A

2
nd

order
polynomial trend analysis
was used
as
the
most appropriate fit
(
regression co
-
efficient
of
R
2
=0.86).

13


However, as the scatter in Figure
4

indica
tes, there is a substantial degree of variability in the
modelled peak flows between St George and Brenda.



Figure
4

Correlation between modelled flow at St. George and Brenda under without
development conditions

The variability in the modelled peak fl
ows between St George and Brenda (as shown in Figure
4
) is
reflected in gauged flows at the two sites.

A comparison of peak discharges gauged at St. George
(gauge number
422201E
) and the Culgoa River at Brenda (gauge number
422015
) for the period
October 1
971 to
August 2011 is shown in Table 5
.
An example of the variability
is shown by the
1974, 1976,
1981

and 1984

flow events. Each event shows a similar peak
in
gauged flow
s

at St.
George (71
,
651,
77
,
538,
74
,
286

and

65
,
838
ML/d
respectively) however corresponding flows as
gauged at Brenda show significant variability
(
28
,
205, 14
,
889,
8
,
639

and

20
,
977 ML/d respectively
)
.

The significant variability in the relationship between flows at St. George and Brenda (as shown by
both modell
ed and gauged data) is consistent with the complexity of the hydrology of the Lower
Balonne floodplain and the highly variable climatic patterns of the system.


The regression analysis equation was applied to determine for each vegetation community a flow

threshold at Brenda equivalent to key thresholds at St. George (Table 6). These flow thresholds
estimated for peak flows at Brenda were used to determine the site
-
specific flow indicators for the
Lower Balonne Floodplain to achieve the ecological target o
f providing a flow regime which ensures
the current extent of native vegetation of the riparian, floodplain and wetland communities is
sustained in a healthy, dynamic and resilient condition.


y =
-
1E
-
06x
2

+ 0.4284x + 1377.7

R² = 0.86

0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
Culgoa River Flow at Brenda (ML/d)

Balonne River Flow at St.George (ML/d)


14


Table 5

Gauged Flows at
St. George and Brenda (1971


2011)

B
alonne River at St. George (422201E)

Culgoa River at Brenda (422015)

Gauged Flow (ML/d)

Date

Gauged Flow (ML/d)

Date

97,956

2/01/1972

20,759

21/01/1972

45,342

15/11/1972

8,845

3/12/1972

71,651

3/02/1974

28,205

28/02/1974

77,538

11/01/1976

14,889

24/01/1976

84,836

2/03/1976

33,082

16/03/1976

123,490

17/03/1977

20,400

4/04/1977

74,286

23/02/1981

8,639

6/03/1981

54,320

7/06/1981

10,688

20/06/1981

82,175

8/03/1982

12,456

28/03/1982

177,021

16/05/1983

53,658

26/05/1983

112,784

7/07/1983

39,570

17/07/1983

121,321

4/12/1983

20,403

19/12/1983

65,838

6/02/1984

20,977

25/02/1984

84,876

13/08/1984

40,288

27/08/1984

71,133

5/03/1988

8,260

17/03/1988

120,931

25/04/1988

40,248

4/05/1988

43,777

3/05/1989

10,761

20/05/1989

218,897

25/04/1990

47,852

4/05/1990

44,490

15/12/1993

4,192

15/12/1993

63,327

16/03/1994

13,685

31/03/1994

28,083

7/12/1995

5,506

1/01/1996

160,669

21/01/1996

29,327

3/02/1996

119,928

20/05/1996

28,181

2/06/1996

32,699

9/02/1997

3,137

15/02/1997

58,596

21/02/97

10,269

10/03/1997

39,146

16/02/1998

2,649

1/03/1998

101,467

9/09/1998

16,378

21/09/1998

44,201

26/09/1998

10,633

8/10/1998

49,272

26/01/2008

3,246

6/02/2008

261,128

8/03/2010

28,795

19/03/2010

255,706

10/01/2011

78,026

18/01/2011

38,644

27/03/2011

8,370

11/04/2011

44,867

26/04/2011

8,246

7/05/2011





15


Table
6

The relationship between ecologically relevant thresholds as defined for the Balonne
R
iver at St. George as expressed at Brenda on the Culgoa River using
the
regression
equation in Figure
4

Target

Ecologically relevant threshold
at St. George (ML/d)

Correlated flows at Brenda
(ML/d) (
s
ee Figure
4
)

Inundation of riparian river red gum and
coolibah forests

26,000

11,840

Inundation of lignum communities and
coolibah open forest / woodland

Floodplain
connections

45,000

18,630

70,000

26,465

Significant
f
loodplain
i
nundation

120,000

38,385

Frequency and duration of flow thresholds

To inform the frequency and duration of flow indicators, the MDBA has collated available
information on the inundation patterns needed by flood dependent vegetation communities which
occur within the Lower Balonne floodplain
(
Table

7
). Generally, there is
a lack of site
-
specific
information for the vegetation communities of the Lower Balonne and
information on the
general
water requirements
of

key vegetation species from throughout the Murray
-
Darling Basin has been
drawn upon.

Generally, the flow indicator
metric with the greatest level of uncertainty across the Basin is the
definition of the desirable inundation frequency. This uncertainty is due to a number of reasons.
Firstly, it is likely that there are thresholds for many plants and animals beyond which

their survival
or ability to reproduce is lost, but the precise details of those thresholds are mostly unknown

or
where there is information (for instance river red gum communities) our knowledge is evolving.
Secondly, vegetation communities are located a
cross the floodplain and would have experienced
some variability in their inundation frequency under pre
-
development conditions which
subsequently makes specification of a single frequency metric deceptively certain. For many species
and ecological communi
ties the relationship between water provisions and environmental
outcomes may not be threshold based, rather there could be a linear relationship between flow and
the extent of environmental outcomes or the condition of a particular ecological
species/comm
unity.

Recognising the degree of confidence in specifying a desirable frequency, ‘low‐uncertainty’ and
‘high‐uncertainty’ frequency of flow events have been specified (Table 8). For the low‐uncertainty
frequency, there is a high likelihood that the environmental
objectives and targets will be achieved.
The lower boundary of the desired range is referred to here as the high uncertainty frequency which
is effectively the best estimate of the threshold, based on current scientific understanding, which, if
not met, ma
y lead to the loss of health or resilience of ecological communities, or the inability of
species to reproduce frequently enough to sustain populations. The high‐uncertainty frequencies
attempt to define critical ecological thresholds. The high uncertainty

frequency is considered to
represent a boundary beyond which there is a high likelihood that the objectives and targets will
not be achieved.



16


Table
7

Flood frequency and duration for selected flood
-
dependent
species

River Red Gum (
Eucalyptus camaldulens
is)

River red gums are opportunistic water users and are able to meet their needs using water from a variety of sources. They
are also tolerant of elevated salinity levels (Roberts
and

Marston 2011).
R
iver red gums have mechanisms to avoid serious
water de
ficit including a deep root system that allows them to access soil water and groundwater (Roberts
and

Marston
2011).

Frequency of inundation


About every one to three years for forests and about every two to four years for woodlands

(Roberts and Marston 2
011)
.

Critical Interval between inundations


Do not form a seed bank, hence it is important to maintain trees in good condition
so that a good supply of seed is available. Inundation required after about
three

years for forests and five to seven years
for woodlands

(Roberts and Marston 2011)
. Longer intervals may be tolerated periodically, but if these become routine
then tree condition is likely to deteriorate in the long term

(Roberts and Marston 2011)
.

Dura
tion of inundation
-

About five to seven months for forests, and about two to four for woodlands


(Roberts and
Marston 2011)
.

Lignum (
Muehlenbeckia flor
ulenta
)

Water regime is a very strong influence on lignum growth and reproduction. Frequency and duration of inundation are the
most important components for maintaining adult lignum in good condition (Roberts
and

Marston 2011).


Frequency of inundation


About
every one to three years for large shrubs with vigorous canopy; every three to five years
for healthy shrubs

(Roberts and Marston 2011)
. For maintenance of small shrubs less frequent inundation of every seven
to 10 years is tolerable however these will no
t be suitable as nesting platforms

(Roberts and Marston 2011)
.

Duration of inundation
-

About three to seven months for vigorous canopy

(Roberts and Marston 2011).

Critical Interval between inundations


inundation required after five to seven years to mai
ntain vigour

(Roberts and
Marston 2011)
.

Coolibah (
Eucalyptus coolabah)


In their review of literature for selected wetland and floodplain species, Roberts
and

Marston (2011) found that the
importance of flooding for adult
c
oolibah had not been establishe
d. Roberts
and

Marston (2011) found that inundation is
probably important for seedling establishment, and a sequence of floods, or flood and wet years, may be necessary to
ensure seedlings are well established.

As a summary Roberts
and

Marston (2011) foun
d that although tolerant of hot dry conditions and infrequent flooding,
c
oolibah is unlikely to persist if flow regime or regional hydrology becomes substantially drier.

Frequency of inundation


About every
10

to
20

years.

Duration of inundation


Not
known.

Critical Interval between inundations


Uncertain. Can maintain fair to good condition for possibly as long as 10


20
years.

River Cooba (
Acacia stenophylla
)

In their review of literature for selected wetland and floodplain species, Roberts
and

M
arston (2011) found that flooding was
important in determining the vigour of river cooba and implicated in germination and establishment of the species.

The following information is taken from (Roberts
and

Marston 2011).

Frequency of inundation


About
every three to seven years for large shrubs with vigorous canopy

(Roberts and Marston
2011)
.

Duration of inundation
-

About two to three months

(Roberts and Marston 2011)
.

Critical Interval between inundations


Not known, possible maintains vigour up to f
ive years without flooding, with trees
near creeks and waterholes able to maintain vigour for much longer periods

(Roberts and Marston 2011)
.




17


Proposed flow indicators

Based on information outlined in the previous two sections, the following summarises t
he
judgements made on how the

flow

indicator
s

will achieve the ecological target of providing a flow
regime which ensures the current extent of native vegetation of the riparian, floodplain and
wetland communities is sustained in a healthy, dynamic and resilient condition in the
Lower
Balonne Floodpl
ain
.

This information also informs the flow indicators needed for a flow regime
which supports key ecosystem functions related to connectivity between the river and the
floodplain.

Riparian Forest

As detailed in previous sections a flow
at Brenda
of
12,0
00 ML/day
is a key threshold at which
inundation occurs for this vegetation community
.

Key flood dependent species found within this community include river red gum and coolibah as
well as river cooba and lignum

(Table 1)
. Generally the vegetation species

that make up this
community need to be inundated for periods up to several months. In defining water requirements
for this community, the MDBA has assumed that river red gums are able to access other sources of
water and that floodplain wetlands will ret
ain water for extended periods (at least 90 days)
following inundation. Given this, the MDBA
concluded

that the required duration for the 12,000
ML/d event is significantly shorter than 90 days. This
is supported

by a
nalysis of modelled flows
under witho
ut development conditions
,

which indicates that
flows with a minimum threshold of
12,000 ML/d at Brenda have a
maximum duration of 47 days and a
median duration of 11 days.
The
MDBA has
chosen the
median duration (under
a
without development
scenario)

of 1
1 days as the
flow indicator and believe that this should be
representative of events which would typically
inundate the Riparian forest of the L
ower Balonne.

The MDBA has also

assumed that an event lasting 11 days is sufficient to fill secondary channels

and
adjacent floodplain waterholes close to the main rivers as well as provide a sufficient period of
inundation for riparian forests.
Table 7 presents information on the inundation requirements of
individual species.

Given that the riparian forest of
the Lower Balonne contain

a

mix of species, the MDBA has
reviewed existing literature related to inundation patterns for vegetation communities containing a
mix of river red gum and coolibah as well as river cooba and lignum.
Inundation mapping
undertaken
as part of developing the

Gwydir Wetlands Adaptive Environmental Management Plan
Floodplain
showed
that lignum, river red gum and some coolibah woodland occurring on the Gwydir
River floodplain
were

inundated by moderate floods with a

1
-
4

year average recu
rrence interval
(
NSW Department of Environment, Climate Change and Water 2011)
.
This regime is broadly
consistent with the species requirements described by Roberts and Marston (2011) (see Table 7).

The MDBA has assumed that the hydrology and climatic patterns of the Gwydir Wetlands and Lower
Balonne are sufficiently similar to allow the
inundation mapping undertaken on Gwydir River
floodplain to be used to inform

the frequency of flows required to in
undate
r
iparian

forest
s

on the
Lower

Balonne.

Given previous assumptions and analysis, the MDBA has specified that an event with a minimum
threshold of 12,000 ML/d at Brenda and a duration of at least 11 days needs to occur on average
once every 3 to 4 y
ears.



18


Lignum Shrublands and Coolibah Woodlands

As detailed in previous sections flows
at Brenda of
between 18,500 and 26,500 ML/d represent a
key range for inundation of

these vegetation communities
.

Key flood dependent species found within th
ese

communi
t
ies

include
coolibah
, lignum and river
cooba

(Table 1).

Hunter (2005) found on the section of the Culgoa River floodplain within the Culgoa
National Park that there was a correlation between major changes in native vegetation composition
and the retention

of water for extended periods. The MDBA has assumed that areas that are
flooded regularly and retain water for extended periods contain high proportions of lignum and
river cooba, while areas which do not retain water are likely to contain less flood dep
endent species

such as coolibah
.

As shown in Table 7,
Roberts and Marston (2011
) report

that the minimum period of inundation
required to maintain
lignum and river cooba in a healthy condition

(as defined by the maintenance
of vigorous canopy) is between t
wo and three months.

In defining flow indicators for these
communities, the MDBA has assumed that once
inundated
,

floodplain wetlands will retain water for
at least
two
to
three
months

and

has determined that the required duration for the 18,500 ML/d
and 2
6,500 ML/d
event
s

is significantly shorter than
two


three months
. This is supported by
a
nalysis of modelled flows under without development conditions which indicates that
flows with a
minimum threshold of 18,500 ML/d at Brenda have a

maximum duration
of 40 days and a

median
duration of 9 days.

Similarly
a
nalysis of modelled flows under without development conditions
indicates that
flows with a minimum threshold of 26,500 ML/d at Brenda have a maximum duration
of 36 days and a median duration of 7 days
.

The MDBA has assumed that an event with a median
duration (under a without development scenario) is representative of events which would typically
inundate
l
ignum shrublands and
c
oolibah woodlands of the Lower Balonne.

Based on a review of existing knowledge and information related to lignum communities, Roberts
and

Marston (2011) found that the average flooding frequency expected to maintain healthy lignum
shrubs was every
three to 5 years.

Given previous assumptions
and analysis, the MDBA has specified that an event with a minimum
threshold of 18,500 ML/d at Brenda and a duration of at least 9 days needs to occur on average
once every 4 to 5 years.

Based on Sims (2004) analysis and recommendations within Whittington
et al. (2002), the MDBA
has determine
d

that a threshold of 26,500 ML/d (at Brenda) represents an important transition in
floodplain inundation where floodwaters emerge from the Culgoa River and travel across the
floodplain and re
-
enter the Culgoa downstrea
m. A flow of this magnitude will enable a substantial
exchange of material between the floodplain and its adjoining aquatic ecosystems (Sims 2004) and
is likely to be important in connecting a range of floodplain wetlands to the systems main channels.

T
he MDBA has
assumed

that a flow of 7 days is sufficient to provide full connection between the
system’s main channels and its floodplain and in doing so inundate channels, depressions and low
lying areas across large sections of the floodplain. The MDBA h
as also assumed that these areas will
retain water for extended periods.

Roberts
and

Marston (2011) found that to maintain small lignum shrubs in good health
,

inundation
every seven to 10 years is required. Given previous assumptions and analysis, the MD
BA has

19


specified that an event with a minimum threshold of 26,500 ML/d at Brenda and a duration of at
least 7 days needs to occur on average once every 7
-

10 years.

The water regime specified for lignum has been assumed by the MDBA to also be sufficient

for the
establishment of coolibah seedlings. Broadly, this assumption is supported by work undertaken in
the Gwydir system. I
nundation mapping undertaken in the Gwydir system as part of the Gwydir
Wetlands Adaptive Environmental Management suggests that

coolibah woodlands are inundated by
large flows that occur infrequently (annual recurrence interval (ARI) of 5
-

20 years) (NSW
Department of Environment, Climate Change and Water 2011). While Wilson et al (2009) describes
the approximate flood frequency

of coolibah communities in the Lower Gwydir prior to river
regulation as being once every 10
-
20 years.

Significant Floodplain Inundation

The 38,500 ML/day
(as measured at Brenda)
flow threshold provides water for the floodplain as a
whole system and the
ecosystem functions that sustained the Lower Balonne floodplain in a
healthy, dynamic and resilient condition.

Extensive areas of native grassland are found across Lower Balonne Floodplain
(
Smith et al. 2006
)
and
are commonly dominated by species such as
Mitchell Grass (
Astrebla
spp.) and Wire Grass
(
Aristida
spp.)

(Smith et. al 2006).

As identified by Sims (2004),
other common grassland species
found on
the floodplain between St. George and the NSW border (Table 1)
include
warrego summer
grass (
Paspalidum

jubiflorum
)

and
curly mitchell grass (
Astrebla lappacea
)
. Sims and Thoms (2002)
and Sims (2004) suggest these areas are generally inundated by large flood events with average
recurrence intervals of 10 years or greater.

Like the Lower Balonne system, n
ative grasslands are common on the
Gingham and Lower Gwydir
floodplains and

occur on slightly elevated areas. Common species include warrego summer grass
(
Paspalidum jubiflorum
), native millet (
Panicum decompositum
), Queensland blue grass
(
Dicantheum seric
eum
), curly mitchell grass, (
Astrebla lappacea
), windmill grass (
Chloris truncata
),
curly windmill grass (
Enteropogon acicularis
) and Australian cup grass (
Eriochloa australiensis
)
(McCosker 2007).

Inundation mapping undertaken in the Gwydir system suggest
s that native
grasslands within the Gwydir Wetlands are inundated by large flows that occur very infrequently
(ARI of 10
-

20 years) (NSW Department of Environment, Climate Change and Water 2011).


The MDBA has used the analysis undertaken by

Sims and Tho
ms (2002) and Sims (2004)

and
NSW
Department of Environment, Climate Change and Water
(
2011
) to inform the
desired
frequency of
the flow indicator.

As part of an assessment of plant community responses to wetting and drying in arid floodplain
systems,
Capon (2003) suggests that flooding induces increases in productivity, particularly total
cover, in floodplain grass communities. However
,

Capon (2003) did not indicate that a particular
duration or frequency of event was required by these communities.

R
ecognising that floodplain inundation is important for a range of ecosystem functions such as the
long term
-
persistence of fish assemblages in lowland rivers (Balcombe et al
.

2005)
,

supply of
dissolved organic carbon (Thoms 2003) and the productivity of te
rrestrial vegetation communities
(Capon 2003), the MDBA has specified a site
-
specific indicator flow to achieve broad scale floodplain
inundation. This will provide
a flow regime which supports key ecosystem functions related to
connectivity between the r
iver and the floodplain.


20


Analysis of modelled flows under without development conditions indicates that
flows with a
minimum threshold of 38,500 ML/d at Brenda have a

maximum duration of 30 days and a

median
duration of 6 days
.

As with other flow indicator
s, the MDBA has relied on a hydrological analysis of without
development events to determine the duration of the 38,500 ML/d
flow indicator
at Brenda
.
The
MDBA has assumed that an event with a median duration (under a without development scenario)
is repre
sentative of events which would typically
achieve broad scale floodplain inundation
.

Given previous assumptions and analysis, the MDBA has specified that an event with a minimum
threshold of 38,500 ML/d at Brenda and
duration

of at least 6 days needs to oc
cur on average once
every 20 years to achieve this ecological target for key ecosystem functions.

5.2.2.

Waterbirds

The MDBA is confident that the site
-
specific flow indicators determined to achieve the ecological
targets for ensuring the current extent of native

vegetation of the riparian, floodplain and wetland
communities will also have valuable beneficial effects on the life
-
cycle and habitat requirements of
waterbirds.

Recognising

that major colonial

waterbird breeding events in the region occur
in

the
Narran

Lakes
System
,

the vegetation communities found on the broader Lower Balonne floodplain
are
likely
to support
these events by providing foraging opportunities for key waterbird species.

5.2.3.

Other Biota

The high variability of flows in the Lower Balonne system

means that the system experiences long
periods of low
-
flows or cease
-
to
-
flow periods. For aquatic fauna populations, this places greater
emphasis on sections of the channel capable of holding water for extended periods. These pools act
as vital habitat du
ring times of low
-
flow, with many species of fish and invertebrates persisting in
these areas until larger flows occur (Balcombe et al. 2006; Balcombe et al. 2007; Bunn et al. 2006).
There are three major attributes of waterhole refugia which contribute to

their ability to sustain
biota: the length of time they retain water during no
-
flow events, the quality of the refuge
(including water quality and habitat availability) and connectivity between waterholes (Balcombe et
al. 2006; Bunn et al. 2006). The main
tenance of these waterholes is associated with the ecological
targets of providing flow regimes supporting key ecosystem functions and maintaining viable
populations of key aquatic species.

A reconnaissance survey conducted in November 2007 following an ex
tended 44
-
month period of
low to no
-
flows identified 22 substantial refugia waterholes in the Lower Balonne system (Webb
2009). The majority of these waterholes (
12
) were located on the Culgoa River, three on the
Bokhara (behind low
-
level weirs) and five o
n the Narran River (Figure
5
; Webb 2009).

DERM (2010) developed a relationship between pool depth and persistence

as part of an
assessment of waterhole refugia in the nearby Moonie River catchment. DERM (2010) determined
that persistence time (measured in days) for waterholes in the Moonie system could be quickly
determined as approximately 170 days per metre of maxim
um depth.



21



Figure
5

Substantial refugia waterholes within the
Lower Balonne Floodplain

(Source: Webb
2009).

DERM (2011a) suggests that refugia waterholes in the Queensland section of the Lower Balonne
have maximum depths up to 5
-
6 metres. The MDBA has a
ssumed that the

relationship between
pool depth and persistence

determined by DERM (2010) as part of an assessment of waterhole
refugia in the nearby Moonie River catchment are applicable to the waterholes of the Lower
Balonne. Using the above relationship
, waterholes in the
Lower Balonne Floodplain

will retain water
for a maximum of around 28 months assuming an initial depth of 5 metres and no inflows. The
MDBA has assumed that the limited analysis of waterhole depth undertaken by DERM (2011a) is
represent
ative of waterhole depth across the entire system.

Habitat conditions within waterholes may also decline as water levels recede, meaning that a
waterhole could become unsuitable as habitat for some species long before it dries completely
(DERM 2010). With
this in mind it is assumed that pools must contain at least one metre of water in
order to provide suitable habitat.
Based on the work of DERM (2010, 2011a), t
o ensure 1 metre of
water is retained in pools, a replenishment flow along the system is required

at a maximum interval
of 680 days or 22 months.

To determine the flows required to maintain these critical refugia waterholes, observed flows were
compared between the St George gauge on the Balonne River
,

the gauge upstream of Collerina at
the lower en
d of the Culgoa River, and the Wilby Wilby gauge on the Narran River
,

for a five year
period (1/07/1973


30/06/1978) prior to major development in the system.

Analysis of flows from these gauges shows that during the five year period there were 6 events
which reached a peak flow at St. George between 4,000 and 6,500 ML/d. Generally these flows

22


correlated to peak flows of between 500


4,000 ML/d upstream of Collerina and between 600


1,600 ML/d at Wilby Wilby (Figures
6

to 1
1
). Each of the six events mai
ntained a flow at St. George
of 2,500 ML/d for between 4 and 11 days, and 1200 ML/d for between 3 and 7 days at Brenda
.
When measured at St. George,
t
he flow volume of these events

generally range

between 20,000
and 60,000 ML
which
is co
mparable to the tot
al volume
currently released from Beardmore Dam to
maintain waterholes for stock and domestic purposes
(Brizga 2011
)
.

However given the outlet
capacity of Beardmore dam (1000 ML/d at full supply level


DERM 2011b)
,

the patterns of releases
currently made from Beardmore
Dam
are significantly different from the events shown in the
following figures.

These flows would connect all the vital waterholes along the length of these rivers. It is assumed
that a flow of this m
agnitude at St

George would also connect waterholes along the Bokhara River.



0
1000
2000
3000
4000
5000
6000
7000
13/07/1973
23/07/1973
2/08/1973
12/08/1973
22/08/1973
Flow (ML/D)

BALONNE RIVER AT ST. GEORGE
CULGOA RIVER AT U/S COLLERINA (MUNDIWA)
NARRAN RIVER AT WILBY WILBY (BELVEDERE)
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
14/09/1973
24/09/1973
4/10/1973
14/10/1973
24/10/1973
3/11/1973
Flow (ML/D)

BALONNE RIVER AT ST. GEORGE
CULGOA RIVER AT U/S COLLERINA (MUNDIWA)
NARRAN RIVER AT WILBY WILBY (BELVEDERE)

23




0
500
1000
1500
2000
2500
3000
3500
4000
4500
11/11/1973
21/11/1973
1/12/1973
11/12/1973
21/12/1973
31/12/1973
Flow (ML/D)

BALONNE RIVER AT ST. GEORGE
CULGOA RIVER AT U/S COLLERINA (MUNDIWA)
NARRAN RIVER AT WILBY WILBY (BELVEDERE)
0
1000
2000
3000
4000
5000
6000
7000
21/04/1974
1/05/1974
11/05/1974
21/05/1974
Flow (ML/D)

BALONNE RIVER AT ST. GEORGE
CULGOA RIVER AT U/S COLLERINA (MUNDIWA)
NARRAN RIVER AT WILBY WILBY (BELVEDERE)

24




Figures
6

to 1
1

Observed flows from six events at St. George, upstream of Collerina at the lower
end of the Culgoa River, and the Wilby Wilby gauge on the Narran Riv
er



0
1000
2000
3000
4000
5000
6000
18/11/1974
28/11/1974
8/12/1974
18/12/1974
28/12/1974
7/01/1975
Flow (ML/D)

BALONNE RIVER AT ST. GEORGE
CULGOA RIVER AT U/S COLLERINA (MUNDIWA)
NARRAN RIVER AT WILBY WILBY (BELVEDERE)
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
28/10/1975
7/11/1975
17/11/1975
27/11/1975
7/12/1975
17/12/1975
Flow (ML/D)

BALONNE RIVER AT ST. GEORGE
CULGOA RIVER AT U/S COLLERINA (MUNDIWA)
NARRAN RIVER AT WILBY WILBY (BELVEDERE)

25


Proposed flow indicator

A flow indicator to maintain critical in
-
channel habitat has been proposed for the Culgoa River at
Brenda given that the majority of identified refugia waterholes are located on the Culgoa River and
also due to its location do
wnstream of major diversions for consumptive use. To ensure waterholes
within the Lower Balonne system retain at least one metre of water, flows of 1,200

ML/d for 7 days
at Brenda should occur at a maximum interval of 22 months (1.8 years). A maximum inter
val
between flows of 28 months (2.3 years) is likely to ensure that a number of deeper waterholes will
be maintained as drought refuges. However, it is expected that increasing the maximum interval
between flows of 1,200

ML/d for 7 days at Brenda from 1.8
to 2.3 years is likely to reduce the
number of waterholes able to adequately support critical in
-
channel habitat.

The proposed flow indicators are consistent with the hydrology of the Lower Balonne system prior
to development. In order to achieve the
objective of maintaining key waterholes as drought refugia
the volume of an event is likely to be the key driver. As such, water could be delivered in a different
pattern to the proposed flow indicator and still achieve the objective.

5.2.4.

Summary

By analysing

modelled flow data for the period 1895
-
2009, the
frequency

of

specified

flow

indicators
under without development and current development scenarios has been determined.

In summary, t
he MDBA has prescribed the site
-
specific flow indicators
(Table 8)
for the
Lower
Balonne Floodplain

based on available information and analysis of flow data. As

the floodplain
system is less studied than other locations in the Basin, its environmental water requirements have
a higher degree of uncertainty compared to othe
r hydrologic indicator sites.


26


Table 8

Site
-
specific ecological targets and associated flow indicators

for the
Lower Balonne
River
Floodplain

System

Note:

Multiplication of the flow rate by the duration and frequency does not translate into the additional volume of water the site

needs to be
environmentally sustainable. This is because part of the required flow is already provided under baseline conditions
. A
dditional environmental water
required is the amount over and above the baseline flows.


Site
-
Specific Ecological Targets

Site
-
Specific Flow Indicators

Without developme
nt and baseline
event frequencies

Event

Average
period between events (years)

except where labelled

A
verage period
between events

(
except where
labelled)

under
modelled without
development
conditions (years)

Average
period
between events
(
except where
labelled)

under

modelled
baseline
conditions (
years)

Flow rate
required
(measured at
Brenda
-

ML/d)

Duration


minimum
continuous
(days)

Timing

Low uncertainty
(years)

High uncertainty
(years)

Provide a flow regime which ensures the current
extent of
native vegetation of the riparian, floodplain
and wetland communities is sustained in a healthy,
dynamic and resilient condition

Provide a flow regime which supports the habitat
requirements of waterbirds

Provide a flow regime which supports a range of
nat
ive aquatic species (e.g. fish, frogs, turtles,
invertebrates)

Provide a flow regime which supports key ecosystem
functions, particularly those related to connectivity
between the river and the floodplain

1,200

7

Preferably
summer /autumn
but timing not
co
nstrained to
reflect that high
flows depend on
occurrence of
heavy rainfall and
will be largely
unregulated
events

1.8 (
maximum
period between
events)

2.3 (maximum
period between
events
)

1.7

(maximum
period between
events
)

3.5

(maximum
period between
events
)

12,000

11

3

4

1.7

6.7

18,500

9

4

5

2.4

8.7

26,500

7

7

10

4.5

8.7

38,500

6

20

20

10.3

28.5


27


6.

Summary and conclusion

The
Lower Balonne
F
loodplain

is
a key environmental

asset with
in

the Basin

and is an important site
for the determination of the environmental water requirements of the Basin. MDBA has
undertaken
a d
etailed
eco
-
hydrological
assessment
of
the
F
loodplain

s

envir
onmental water requirements
.
Specified flow indicators are indicative of a long
-
term
flow

regime required to enable the
achievement of site
-
specific ecological targets at the

Lower Balonne
F
loodplain

and for the broader
river valley and reach.
A
long with other
site
-
specific flow indicators
developed across the Basin at
other hydrologic indicator sites, these environmental flow requirements were
integrated
within
hydrological models to
inform

the ESLT.

This process

is described in further detail w
ithin the
companion report on the modelling process

Hydrologic modelling to inform the
proposed
Basin
Plan
: Methods and results


(MDBA 2012)
.

The flow indicators in this report are used to assess potential Basin Plan scenarios. MDBA (2012)
summarises how
the proposed draft Basin Plan released in November 2011 performs against flow
indicators for
the
Lower Balonne Floodplain
.




28


References

Balcombe, SR, Arthington, AH, Foster, ND, Thoms, MC, Wilson, GA & Bunn, SE 2006, ‘Fish
assemblages of an Australian dryl
and river: abundance, assemblage structure and recruitment
patterns in the Warrego River, Murray

Darling Basin’,
Marine and Freshwater Research,
vol. 57, pp.
619

633.

Balcombe, SR,
Bunn, SE,
Arthington, AH
, Fawcett JH, McKenzie
-

Smith, FJ, & Wright
, A
2007
,

Fish
larvae, growth and biomass relationships in an Australian arid zone river: links between floodplains
and waterholes
Freshwater Biology

vol.
52, pp
.
2385

2398

Balcombe, SR, S.E. Bunn, SE, McKenzie
-
Smith, FJ, Davies, PM 2005
,

Variability of fish diets

between
dry and flood periods in an arid zone floodplain river
. A

Cooperative Research Centre for Freshwater
Ecology, Centre for Riverine Landscapes, Faculty of Environmental Sciences, Griffith University,
Nathan, Queensland, Australia

Brizga S, 2011,
Env
ironmental Water Needs Assessment for the Lower Balonne Floodplain and
Narran Lakes Ecological Assets

Queensland Government, Brisbane.

Bunn, SE & Arthington, AH 2002, ‘Basic principles and ecological consequences of altered flow
regimes for aquatic biodive
rsity’,
Environmental Management
, vol. 30, pp. 492
-
507.

Bunn, SE, Thoms, MC
, Hamilton
, SK & Capon, SJ 2006,
Flow variability in dryland rivers: boom,

bust
and the bits in between,
River Research and Applications
,

vol.
22,
pp.
179
-
186.

Capon SJ 2003,

Plant community responses to wetting and drying in a large arid floodplain
’,

River
Research and Applications
,
vol.
19,
pp.
509
-
520.

CSIRO 2008,
Water availability in the Condamine

Balonne
, a report to the Australian Government
from the CSIRO Murray

Darling

Basin Sustainable Yields Project, CSIRO, Australia. 169pp.

Cullen P, Marchant, R & Mein, R 2003,
Review of science underpinning the assessment of the
ecological condition of the Lower Balonne system
, report to the Queensland Government
Independent Scienti
fic Review Panel, Brisbane
.


Department of the Environment, Water, Heritage and the Arts 2001,
Directory of Important
Wetlands in Australia
, Australian Wetlands Database

spatial data, viewed November
2008,
http://asdd.ga.gov.au

Department of the
Environment, Water, Heritage and the Arts 2008, National framework and
guidance for describing the ecological character of Australian Ramsar wetlands, module 2 of the
national guidelines for Ramsar wetlands


implementing the Ramsar Convention in Australia
,
viewed 5 January 2010
www.environment.gov.au/water/publications/environmental/wetlands/module‐2‐framework.html

DERM (
Queensland Department of Environment and Resource Management) 2010
,

Refugial
waterholes project: research highlights, Queensland Governme
nt, Brisbane.

DERM (
Queensland Department of Environment and Resource Management
)

2011
a
,

Murray
-
Darling
Basin Plan


Assessment of flow scenario implications for ecological assets of the upper Murray
-
Darling Basin, Queensland Government, Brisbane.


29


DERM (
Qu
eensland Department of Environment and Resource Management
)

2011
b,

Condamine
and Balonn
e Resource Operations Plan
, Queensland Government, Brisbane.

Dick, R 1993,
The vegetation of the Wombeira land system and the floodplains of the Culgoa, Birrie
and Narra
n Rivers in NSW,
November
1990
,
N
ew
S
outh
W
ales

National Parks & Wildlife Service,
Hurstville
,

NSW.

Hunter, JT 2005
,

Vegetation of Culgoa National Park, central northern New South Wales
.
Cunninghamia

vol.
9
,
pp.
275
-
284.

Kingsford, RT, Thomas, RF & Knowles,

E 1999, Wetland GIS of the Murray

Darling Basin, NSW
National Parks and Wildlife Service & Murray

Darling Basin Commission, Canberra.

Lake, PS 2003, ‘Ecological effects of perturbation by drought in flowing waters’,
Freshwater Biology
,
vol.

48, pp.

1161

1
172.

McCosker, RO 1996,
An environmental scan of the Condamine

Balonne River system and associated
floodplain
, LANDMAX Natural Resource Management Services, Armidale
,

New South Wales
.

McCosker
,

RO 2007
,

Gwydir Floodplain Vegetation Map 2005 and Explanatory

notes on Vegetation
Communities
. Report to the NSW Department of Environment and Conservation

MDBA (Murray

Darling Basin Authority) 2009,
Options for environmental water: An evaluation of
the 2008 Narran Lakes Environmental water purchase
, viewed February

2012,
http://www.mdba.gov.au/files/publica
tions/Options
-
for
-
environmental.

MDBA
(Murray
-
Darling Basin Authority)
2011
,
The propose
d

environmentally

sustainable level of
take” for surface water of the Murray
-
Darling Basin: Method and Outcomes.
Murray
-
Darl
ing Basin
Authority
, Canberra.

MDBA
(Murray
-
Darling Basin Authority) 2012
, Hydrological modelling to inform the Basin Plan.
Murray
-
Darling Basin Authority, Canberra.

NSW Department of Environment, Climate Change and Water 2009,
Atlas of NSW wildlife
,
viewed
October 2009, <www.wildlifeatlas.nationalparks.nsw.gov.au/wildlifeatlas/watlas.jsp>.

NSW Department of Environment, Climate Change and Water 2011, ‘Gwydir Wetlands: Adaptive
Environmental Management Plan


synthesis of information projects and actio
ns’. NSW Department
of Environment, Climate Change and Water, Sydney.

NSW

National Parks & Wildlife Service 2003,
Culgoa National Park Plan of Management
, NSW
National Parks & Wildlife Service, Bourke, New South Wales.

NSW

Scientific Committee 2011,
Coolib
ah
-

Black Box Woodland of the northern riverine plains in
the Darling Riverine Plains and Brigalow Belt South bioregions
-

reject delisting of ecological
community
, viewed 19 August 2011,
http://www.environment.nsw.gov.au/determinations/coolibahblackboxre
jectdelistfd.htm

NSW Western Catchment Management Authority 2006, Lower Balonne Scoping Study: Hydrology
Review, A Final report produced by Snowy Mountains Engineering Corporation (SMEC) for the New
South Wales Western CMA, Sydney, pp. 42

Rayburg S & Thom
s M 2008
, A real time hydrological model for the Narran Lakes Floodplain Wetland
Ecosystem
, Murray

Darling Basin Commission, Canberra.



30


Roberts, J & Marston, F 2000,
Water regime of wetland and floodplain plants in the Murray

Darling
Basin


a source book
of ecological knowledge
, technical report 30/00, CSIRO Land and Water,
Canberra.

Roberts, J & Marston, F 2011,
Water regime for wetland and floodplain plants. A source book for the
Murray

Darling Basin.
National Water Commission
, Canberra.

Sheldon, F, Th
oms, M, Berry & Puckridge, J 2000, ‘Using disaster to prevent catastrophe: referencing
the impacts of flow changes in large dryland rivers’
,

Regulated Rivers: Research & Management,
vol.

16, pp. 403

420.

Sims, N 2004, The landscape
-
scale structure and func
tioning of floodplains, PhD thesis, University of
Canberra, Canberra

Sims, N &

Thoms, M 2002, ‘What happens when floodplains wet themselves: vegetation response
to inundation on the Lower Balonne floodplain’,
Proceedings of

the structure, function and
mana
gement implications of fluvial sedimentary systems,

International Association of Hydrological
Sciences Publication
,

276.

Sims, N, Thoms, MC, Levings, PF, McGinness, HM 1999,
Large scale vegetation response to wetting
on the Lower Balonne floodplain,
report to the Lower Balonne Floodplain Advisory Committee,
Cooperative Research Centre for Freshwater Ecology, Canberra.

SKM 2007,
High Conservation Value Aquatic Ecosystems project ‐ identifying, categorising and
managing HCVAE, Final report, Department
of the Environment and Water Resources,
16 March
2007.
www.environment.gov.au/water/publications/environmental/ecosystems/hcvae.html

Smith, L, Niel
son, D, Adams, J & James, C 2006
,
Lower Balonne scoping study environment theme
,
Murray

Darling Freshwater
Research Centre, Wodonga
,

V
ictoria
.

Thoms, M. C 2003
,

"Floodplain
-
river ecosystems: lateral connections and the implications of human
interference."
Geomorphology

vol.
56
, pp. 335
-
349.

Thoms, M, Quinn, G, Butcher, R, Phillips, B, Wilson, G, Brock, M, & Gaw
ne, B 2002,
Scoping study for
the Narran Lakes and Lower Balonne floodplain management study

(R2011), Cooperative Research
Centre for Freshwater Ecology, Canberra.

Webb, M 2009, ‘
Biocomplexity in Dryland River Systems

t
he influence on flow regime on ecolog
ical
character and foodweb structure’, Masters Thesis, University of Canberra, Canberra.


Whittington, J, Bunn, S, Cullen, P, Jones, G, Thoms, M, Quinn, G & Walker, K 2002,
Ecological
assessment of flow management scenarios for the Lower Balonne
, report to

the Queensland
Department of Natural Resources & Mines, Cooperative Research Centre for Freshwater Ecology,
Canberra.

Wilson, GG, Bickel, TO, Berney, PJ & Sisson, JL 2009,
Managing environmental flows in an
agricultural landscape: the Lower Gwydir floodpl
ain,

final report to the Department of the
Environment, Water, Heritage and the Arts, University of New England and Cotton Catchment
Communities Cooperative Research Centre, Armidale, New South Wales.




31


Appendix A

Data used in producing hydrologic
indicator site maps

Data

Dataset name

Source
a

Basin Plan regions

Draft Basin Plan Areas 25 May 2010

Murray

Darling Basin Authority (2010)

Dam walls/barrages

GEODATA TOPO 250K Series 3 Topographic Data

Geoscience Australia 2006

Gauges

100120 Master AWRC
Gauges


Icon sites

Living Murray Indicative Icon Site Boundaries

Murray

Darling Basin Commission
(2007)

Irrigation areas

Combined Irrigation Areas of Australia Dataset

Bureau of Rural Sciences (2008)

Lakes

GEODATA TOPO 250K Series 3 Topographic Data

Geoscience Australia (2006)

Maximum wetland
extents

Wetlands GIS of the Murray

Darling Basin Series 2.0
(Kingsford)

Murray

Darling Basin Commission
(1993)

National parks/nature
reserves

Digital Cadastral Database

New South Wales Department of
Lands (200
7)

National parks/nature
reserves

Collaborative Australian Protected Areas Database


CAPAD 2004

Department of the Environment,
Water, Heritage and the Arts (2004)

Nationally important
wetlands

Directory of Important Wetlands in Australia Spatial
Databas
e

Department of the Environment,
Water, Heritage and the Arts (2001)

Ocean and landmass

GEODATA TOPO 250K Series 3 Topographic Data

Geoscience Australia (2006)

Ramsar sites

Ramsar wetlands in Australia

Department of the Environment,
Water, Heritage and
the Arts (2009)

Rivers

Surface Hydrology (AUSHYDRO version 1
-
6)

Geoscience Australia (2010)

Roads

GEODATA TOPO 250K Series 3 Topographic Data

Geoscience Australia (2006)

State border

GEODATA TOPO 250K Series 3 Topographic Data

Geoscience Australia (2006
)

State forests

Digital Cadastral Database

New South Wales Department of
Lands (2007)

Towns

GEODATA TOPO 250K Series 3 Topographic Data

Geoscience Australia (2006)

Weirs

Murray

Darling Basin Weir Information System

Murray

Darling Basin Commission
(2001)

Weirs 2

River Murray Water Main Structures

Murray

Darling Basin Authority (2008)

a

Agency listed is custodian of relevant dataset; year reflects currency of the data layer.




32


Appendix B


Species relevant to criteria 1 and 4
:
Lower Balonne

River

Floodpla
in

System

Species

Environment Protection
and Biodiversity
Conservation Act 1999

(Cwlth)

Fisheries
Management Act
2004

(NSW)

Threatened Species
Conservation Act
1995

(NSW)

Amphibians and reptiles




Western blue
-
tongued lizard (
Tiliqua occipitalis
)
3



V

Birds




Australasian bittern (
Botaurus poiciloptilus
)
3




V

Australian bustard (
Ardeotis australis
)
2



E

Barking owl (
Ninox connivens
)
3



V

Black
-
chinned honeyeater (eastern subspecies) (
Melithreptus
gularis gularis
)
3



V

Blue
-
billed duck (
Oxyura
australis
)
1



V

Brolga (
Grus rubicundus
)
1, 2



V

Brown treecreeper (
Climacteris picumnus
)
3



V

Freckled duck (
Stictonetta naevosa
)
1, 2



V

Grey falcon (
Falco hypoleucos
)
2



V

Grey
-
crowned babbler (eastern subspecies) (
Pomatostomus
temporalis
temporalis
)
3



V

Hall’s babbler (
Pomatostomus halli
)
2



V

Hooded robin (
Melanodryas cucullata
)
3



V

Major Mitchell's or pink cockatoo (
Cacatua leadbeateri
)
3



V

Painted honeyeater (
Grantiella picta
)
2



V

Painted snipe (
Rostratula australis

or
R.

benghalensis
)
1

V


E

Red
-
tailed black cockatoo (
Calyptorhynchus banksii
)
2



V

Fish





33


Species

Environment Protection
and Biodiversity
Conservation Act 1999

(Cwlth)

Fisheries
Management Act
2004

(NSW)

Threatened Species
Conservation Act
1995

(NSW)

Silver perch (
Bidyanus bidyanus
)
1


V


Olive perchlet (
Ambassis agassizii
)
1


E


Murray cod (
Maccullochella peelii peelii
)
1

V



Purple spotted gudgeon (
Mogurnda
adspersa
)
1



E

Mammals




Inland forest bat (
Vespadelus baverstocki
)
3



V

Koala (
Phascolarctos cinereus
)
3



V

Little pied bat (
Chalinolobus picatus
)
2



V

Sandy inland mouse (
Pseudomys hermannsburgensis
)
2



V

Stripe
-
faced dunnart (
Sminthopsis macroura
)
3



V

Yellow
-
bellied sheathtail bat (
Saccolaimus flaviventris
)
3



V

Plants




Narrow
-
leafed bumble (
Capparis loranthifolia

var.
loranthifolia
)
1, 2



E

Climbing caustic (
Euphorbia sarcostemmoides
)
2



E

Desert cow
-
vine (
Ipomoea diamantinensis
)
1



E

Winged peppercress (
Lepidium monoplocoides
)
3

E


E

Communities




Lowland Darling River aquatic ecological community
1


E


Coolibah

black box woodland of the northern Riverine Plains in the
Darling Riverine Plains and Brigalow Belt South bioregions
1



E

Brigalow

gidgee woodland/shrubland in the Mulga lands and
Darling Riverine Plains bioregion
1



E

V = vulnerable E = endangered

1

Smith et al. (2006)

2

NSW National Parks and Wildlife Service (2003)

3

NSW Department of Environment, Climate Change and
Water (2009)