Assessment of environmental water requirements for the proposed Basin Plan: Riverland–Chowilla Floodplain 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 [email protected] Internet http://www.mdba.gov.au
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Murray region
Assessment of the Riverland‐Chowilla Floodplain environmental water requirements
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 volumes of water that can be taken from the Basin and they must represent an Environmentally Sustainable Level of Take (ESLT). The method used to determine the ESLT is described in detail within ‘The proposed “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 including 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 requirements of Riverland‐Chowilla Floodplain. It is not expected that the environmental water requirements assessments will remain static, rather it is intended that they will evolve over time in response to new knowledge 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 watering 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 detailed eco‐hydrological assessment of environmental water requirements for a subset of the key environmental assets and key ecosystem functions across the Basin. Effort focused on high flow (freshes, bankfull flows and overbank flows) requirements reflecting the prioritisation of effort on parts of the flow regime that are most sensitive to the determination of the ESLT and SDLs. Riverland‐Chowilla Floodplain is one of the key environmental assets where a detailed assessment of environmental water requirements was undertaken.
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Figure 1: Outline of method used to determine an Environmentally Sustainable Level of Take (Source: MDBA 2011).
Detailed environmental water requirement assessments lead to the specification of site‐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 hydrologic 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 ecological assets and functions. This report provides a description of the detailed eco‐hydrological assessment of environmental water requirements for the Riverland‐Chowilla Floodplain including information supporting the development of site‐specific flow indicators for the site (with reference to flows measured on the River Murray at the
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South Australian border). More information on how the site‐specific flow indicators for Riverland‐ Chowilla Floodplain were used within the Basin‐wide modelling process to inform the ESLT (i.e. Step 5 and 6 in Figure 1) can be found in the report ‘Hydrologic modelling to inform the proposed Basin Plan: Methods and results’ (MDBA 2012). A description 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 Plan’.
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 enables 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 future 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 framework of the Environmental Watering Plan and natural eco‐hydrological cues. 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 water during any one year to achieve environmental outcomes.
2. Site location and extent
The Riverland‐Chowilla Floodplain hydrologic indicator site comprises the Riverland Ramsar site and The Living Murray Chowilla Floodplain and Lindsay–Wallpolla Islands icon site. The Riverland Ramsar site was listed in 1987 covering an area of 30,615 ha that includes the South Australian portion of the Chowilla Floodplain, as well as adjacent wetland and floodplain areas downstream to Renmark (Figure 2). It includes many wetlands and wetland complexes, such as the Ral Ral Creek anabranch (including Lake Merriti) and the Woolenook Bend wetland complex. The Living Murray Chowilla Floodplain and Lindsay–Wallpolla Islands icon site covers 43,856 ha and comprises four main areas of floodplain. The Chowilla Floodplain covers 17,700 ha, of which 74% is in South Australia (noting that the entire Riverland Ramsar site is not included within the boundary of The Living Murray icon site) and 26% is in New South Wales. The other main floodplain components of the icon site are in Victoria. Moving upstream, they are: Lindsay Island (15,000 ha), Mulcra Island (2,156 ha) and Wallpolla Island (9,000 ha). The extent of the indicator site has been defined using a number of data sources. The Wetlands GIS of the Murray–Darling Basin Series 2.0 (Kingsford, Thomas & Knowles 1999) and Directory of Important Wetlands in Australia dataset were used to determine the internal extent of the site (Department of the Environment, Water, Heritage and the Arts 2001). The downstream extent was determined using the Ramsar Wetlands in Australia dataset; and The Living Murray indicative icon site boundaries were used to include the Wallpolla extent. Spatial data used in Figure 2 are listed in Appendix A. Issues with mapping of the boundary of the Riverland Ramsar site have been identified but are yet to be resolved and may result in minor future modifications to the indicator site boundary.
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Figure 2 Location and extent of the Riverland‐Chowilla Floodplain hydrologic indicator site comprising the Riverland Ramsar site and The Living Murray Chowilla Floodplain and Lindsay–Wallpolla Islands icon site. Flow indicators are specified at River Murray South Australian border.
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3. Ecological Values
The Riverland‐Chowilla Floodplain hydrologic indicator site consists of a mosaic of anabranch creeks, wetlands, lagoons, lakes and floodplains. The floodplains are dominated by red gum woodland, lignum shrublands, black box woodlands, grasslands and some localised areas of denser river red gum forest. The indicator site’s vegetation communities have varying locations and extents within the floodplain, with corresponding variations in inundation thresholds (MDBC 2006; Newall et al. 2009; Cale 2009). The Riverland‐Chowilla Floodplain is important as critical habitat for both nomadic and migratory waterbirds during times of drought in central and eastern Australia, including as stop‐over habitat for a number of migratory bird species listed under the Japan–Australia, China–Australia and Republic of Korea–Australia migratory bird agreements (Newall et al. 2009). The anabranch environments present within the Riverland‐Chowilla Floodplain site support significant populations of native fish. In particular, the site provides valuable habitat for Murray cod (Macullochella peelii peelii) populations, allowing different sized Murray cod to exploit different habitats (Zampatti et al. 2008; Newall et al. 2009; Zampatti et al. 2011). This attribute is relatively rare in the post‐regulation River Murray, is largely restricted to this and other Ramsar sites, and represents, to some degree, remnants of main channel environments before regulation. Other animals such as the southern bell frog is supported by the habitats and flow regime in the Riverland Ramsar site. These ecosystems support important species and habitats that are listed in international agreements and include vulnerable and endangered species. Appendix B provides a summary of the conservationally significant species recorded at the floodplain. The ecological values of the Riverland‐Chowilla Floodplain are reflected in MDBA’s assessment against the criteria used by the to identify key environmental assets within the Basin. The MDBA established five criteria to identify assets based on international agreements and broad alignment with the National Framework and Guidance for Describing the Ecological Character of Australian Ramsar Wetlands (Department of the Environment, Water, Heritage and the Arts 2008) and the draft criteria for identifying High Conservation Value Aquatic Ecosystems (SKM 2007). Based on the ecological values identified at Riverland‐Chowilla Floodplain, the site meets all five key environmental asset criteria (Table 1).
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Table 1 Assessment of the Riverland‐Chowilla Floodplain against MDBA key environmental asset criteria.
Criterion Ecological values that support the criterion
1. The water-dependent The Riverland-Chowilla Floodplain indicator site is formally recognised in, or is capable ecosystem is formally of supporting species listed in the Japan–Australia, China–Australia or the Republic of recognised in international Korea – Australia migratory bird agreements. It also contains the Riverland Ramsar agreements or, with site. Species listed in international agreements that have been recorded at the site are environmental watering, is capable of supporting in Appendix B. species listed in those agreements
2. The water-dependent At the time of listing, the Riverland Ramsar site contained excellent regional ecosystem is natural or near- representations of major floodplain systems within the Murray Scroll Belt subregion natural, rare or unique (Newall et al. 2009). The Chowilla Floodplain substantially overlaps the Riverland Ramsar site, and is rare as only one of a few areas of the lower River Murray Floodplain not affected by irrigation, preserving much of its natural character (Newall et al. 2009). Significantly, the Chowilla Floodplain contains the largest remaining area of naturally-occurring river red gum (Eucalyptus camaldulensis) forest in the lower River Murray (Newall et al. 2009).
3. The water-dependent The Riverland-Chowilla Floodplain indicator site is important as critical habitat for both ecosystem provides vital nomadic and migratory waterbirds during times of drought in central and eastern habitat Australia, including as stop-over habitat for a number of migratory bird species listed under the Japan–Australia, China–Australia and Republic of Korea–Australia migratory bird agreements (Newall et al. 2009). The Chowilla floodplain habitat and wetlands has outstanding importance for birds of South Australia and is known to support waterfowl at critical stages of their biological life cycle (Carpenter 1990).
4. Water-dependent ecosystem Species and communities listed as threatened under both Commonwealth and state that supports legislation that have been recorded at the site are in Appendix B. Commonwealth, State or Territory listed threatened A significant population of the nationally listed southern bell frog is supported by the species or communities Riverland Ramsar site which provides the combined habitat of permanent waters with still to slow flowing areas and nearby forests (Newall et al. 2009).
5. The water-dependent The Riverland-Chowilla Floodplain indicator site has a relatively high diversity of ecosystem supports, or with terrestrial and aquatic habitats (MDBC 2006). Over 40 vegetation associations environmental watering is representing 340 plant species have been identified (MDBC 2006). The diverse range capable of supporting, of habitats supports a total of 179 bird species (including 63 wetland-dependent significant biodiversity species), 17 mammal species, 9 species of frog and 16 species of fish (Newall et al. 2009). More than 20,000 waterbird individuals have been recorded, including freckled duck (Stictonetta naevosa), red-necked avocet (Recurvirostra novaehollandiae) and red-kneed dotterel (Erythrogonys cinctus), which represents more than 1% of their estimated global population (Carpenter 1990; Newall et al. 2009). The Riverland- Chowilla Floodplain anabranch environments support significant populations of native fish, including Murray cod (Zampatti et. al 2008; Newall et al. 2009).
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4. Hydrology
The Riverland‐Chowilla Floodplain hydrologic indicator site is located downstream of the Murray– Darling junction and therefore receives flows from both the Murray and Darling Rivers. The largest flows occur when both rivers are in flood. At low flows, the hydrology of the site is governed by the operation of locks 5, 6, 7, 8 and 9. These maintain elevated pools in the River Murray, and permanent water in some anabranch creeks and wetlands. There are localised variations in inundation thresholds across the South Australian, New South Wales and Victorian portions of the Riverland‐Chowilla Floodplain hydrologic indicator site (MDBC 2006), although for the purposes of assessing environmental water requirements there is considerable overlap and consistency. The extent and depth of floodplain inundation is determined by flood magnitude and changes in elevation across the floodplain (Cale 2009). Flows of 40,000 ML/d to 60,000 ML/d are required to overtop the river banks and inundate wetlands and floodplains, with significant floodplain inundation at the upper end of this range (MDBC 2006). About half the Chowilla Floodplain is inundated at flows of 80,000 ML/d and flows in excess of 100,000 ML/d inundate extensive areas of the entire site (MDBC 2006). Newall et al. (2009) mapped inundation thresholds for the Riverland Ramsar component of the hydrological indicator site and these are consistent with the inundation thresholds identified above. River regulation has significantly reduced the magnitude of flows, particularly medium‐sized floods (Cale 2009). Average annual flow to South Australia has also been significantly reduced with a 52% reduction under current water resource development conditions compared to without development conditions (CSIRO 2008). Flows of 80,000 ML/d, which inundate about 50% of Chowilla Floodplain, previously occurred once every two years on average, but now occur once every eight years (Cale 2009). CSIRO (2008) found that as a result of water resource development, the average period between beneficial spring‐summer floods has more than tripled (from 2.4 to 9.3 years). Similarly, the maximum period between events under current conditions is more than five times the maximum period experienced under without development conditions (from 5.7 to 28.7 years). Flood volumes have also been greatly reduced, such that the average annual flood volume is now less than half of the volume compared to without development conditions (from 2431 to 947 GL).
5. Determining the site‐specific flow indicators for the Riverland‐ Chowilla Floodplain
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 targets, which were then applied at a finer scale to develop site‐specific objectives for individual key environmental assets. Using these site‐specific objectives, ecological targets that relate specifically to the Riverland‐Chowilla Floodplain were developed (Table 2). Information underpinning site‐specific ecological targets is shown in Table 2.
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Table 2 Site‐specific ecological targets for the Riverland‐Chowilla Floodplain.
Site-specific ecological targets Justification of targets
Provide a flow regime which The site contains the Riverland Ramsar site. By providing a flow regime that ensures the current extent of supports the maintenance of the current area of wetlands, the ecological native vegetation of the riparian, character of Ramsar site and the broader hydrologic indicator site will be floodplain and wetland conserved. communities is sustained in a The Riverland-Chowilla Floodplain hydrologic indicator site supports a variety of healthy, dynamic and resilient flood dependent vegetation communities. Riverland Ramsar site ecological condition character description specifies a long-term limit of acceptable change as no loss Provide a flow regime which of more than 20% of any wetland or vegetation type over the site as a whole supports the habitat requirements within any 10-year period, and no loss of more than 20% of any habitat type over of waterbirds and is conducive to the site as a whole. This highlights some inconsistencies with ecological successful breeding of colonial character descriptions developed for other Ramsar-listed indicator sites along nesting waterbirds the River Murray (e.g. Barmah and Gunbower forests, Hattah Lakes) which Provide a flow regime which specifies that any change in the distribution or area of vegetation communities supports recruitment opportunities would signal a change in ecological character of the site. for a range of native aquatic Ecological targets for the Riverland-Chowilla floodplain propose to ensure the species (e.g. fish, frogs, turtles, current extent of native vegetation communities is sustained in recognition that it invertebrates) is rare as only one of a few areas of the lower River Murray Floodplain not Provide a flow regime which affected by irrigation, preserving much of its natural character (Newall et al. supports key ecosystem functions, 2009) and to ensure it is representative of the broader environmental water particularly those related to requirements of the lower Murray. connectivity between the river and the floodplain. The Riverland-Chowilla Floodplain is an important area for waterbird breeding and migratory birds (MDBC 2006; Newall et al. 2009). The Riverland Ramsar
site ecological character description specifies no net reduction in waterbird breeding numbers or reduction in waterbird populations (particularly migratory) over any rolling 10-year period. The site supports important habitat and species that are listed in international agreements including vulnerable and endangered species such as Murray cod (Maccullochella peelii peelii) and Murray hardyhead (Craterocephalus fluviatilis). Achieving the targets for floodplain wetlands and waterbirds will ensure inundation of breeding and feeding habitats considered key for a range of fish, amphibian and water-dependent reptile and invertebrate species. Key ecosystem functions 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 of 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 floodplain provides for the exchange of carbon and nutrients (Thoms 2003). The connections are considered essential for the functioning and integrity of floodplain-river ecosystems.
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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 Riverland‐ Chowilla Floodplain, as described below.
5.2 Information used to determine site‐specific flow indicators
5.2.1. Vegetation
The ecological character description for the Riverland Ramsar site identifies the role of vegetation in providing the habitat template (Newall et al. 2009). In turn, vegetation structure and dynamics are influenced by the hydrologic regime, and therefore, vegetation and hydrology are critical components of the site. The development of site‐specific flow indicators to achieve the site specific ecological targets for Riverland‐Chowilla Floodplain focused on assessment of the bankfull and overbank elements of the flow regime necessary to maintain flood dependent vegetation communities. A number of documents have been assessed to determine the flows required to achieve the site‐specific ecological targets, as described below. However, it was found that no single existing plan or document sets out these requirements completely or consistently with other documents. The Riverland Ramsar site ecological character description was used predominately to determine the duration, frequency and timing of site‐specific flow indicators (Newall et al. 2009). A number of other site‐specific resources were drawn upon including a Preliminary review of the MDBA EWRs set for South Australian sites (DWLBC 2010), The Chowilla Floodplain and Lindsay–Wallpolla Islands Icon Site Environmental Management Plan (MDBC 2006), the Chowilla Creek Environmental Regulator Investment Proposal (SA Murray–Darling Basin Natural Resources Management Board 2008), a review of the Chowilla Floodplain’s flooding regime (Cale 2009) and a report of floodplain options for Lindsay, Mulcra and Wallpolla islands (Ecological Associates 2007). To assist in defining ecologically relevant flow thresholds, MDBA undertook analysis of flows required to achieve inundation of different vegetation communities. This was supported largely by River Murray Floodplain Inundation Model data presented in Overton et al. (2006) and Newall et al. (2009). Floodplain inundation modelling confirms that flows of less than 40,000 ML/d are important for inundation of wetland vegetation communities (Figure 3). Flows in excess of 40,000 ML/d are required to inundate key vegetation communities present at Riverland‐Chowilla Floodplain (Figures 3 and 4). River red gum forest and woodland and lignum exhibit a similar pattern of inundation with at least 50% of these vegetation communities being inundated at flows of 60,000 ML/d and at least 80% inundated at flows of 80,000 ML/d (Figure 3). In contrast, black box communities are generally located at higher elevations on the floodplain with less than 20% inundated at flows of 60,000 ML/d and flows in excess of 100,000 ML/d at least half of this community. Despite some differences in inundation thresholds, at the macro scale the hydrology of both the South Australian and Victorian portion of the Riverland‐Chowilla Floodplain are broadly similar. It is therefore sensible to define the flow regime required for both sites together and the flow regime represented by the proposed flow indicators is considered sufficient to cater for the vegetation communities across the Riverland–Chowilla Floodplain.
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70,000
60,000 Wetlands 50,000 Red gum forest Red gum woodland 40,000 Lignum Grasslands/Chenopods 30,000 Black Box Area inundated (ha)
20,000
10,000
0 0 5,000 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 90,000 100,000
Flow (ML/d) max. extent
Figure 3 Flows needed to inundate selected vegetation communities between locks 6 and 9 for the Riverland‐Chowilla Floodplain (Source: adapted from Overton et al. 2006).
100 35,000
90 30,000 80
70 25,000
60 20,000 50 15,000 40
30 communities (%) 10,000 20
5,000 Total area of inundation (ha) 10 Inundation of selected vegetation
0 0 30,000 35,000 40,000 45,000 50,000 60,000 70,000 80,000 100,000 200,000 311,000 Flow ML/day Total Black box Lignum Red gum forest Red gum woodland
Figure 4 Flows needed to inundate selected vegetation communities, Riverland Ramsar site: Riverland–Chowilla Floodplain (Source: adapted from Newall et al. 2009). Note that the proportion of vegetation communities inundated (coloured lines) relates to the Y axis on left‐hand side. The total area inundated (grey shaded area) relates to the Y axis on the right‐hand side.
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Analysis undertaken by DWLBC (2010) also using floodplain inundation modelling suggest that previous assessments of floodplain inundation may underestimate the flows required to inundate flood dependent vegetation communities at Riverland. Similarly, DWLBC (2010) analysis indicates that flows recommended for the Riverland‐Chowilla Floodplain hydrological indicator site may not be sufficient to inundate key vegetation communities at Katarapko and Pike Floodplains located further downstream on the River Murray. MDBA has not been able to determine the reason for these differences and further analysis is required to understand differences between the various assessments and to assess the assumption that environmental water requirements specified are representative for the broader reach of the River Murray downstream of the Darling River junction. However, it is important to note that the approach adopted by the MDBA involves specification of multiple flow indicators to represent an overbank flooding regime and any uncertainties in one indicator are likely to be mitigated by one or more of the other flow indicators. This mitigates to some extent the significance of any discrepancies between the various floodplain inundation modelling data sets.
5.2.2. Waterbirds
A variety of information sources have been used to inform development of site‐specific flow indicators to achieve the ecological target of providing a flow regime which supports the habitat requirements of waterbirds and is conducive to successful breeding of colonial nesting waterbirds (Scott 1997; MDBC 2006; Cale 2009; Overton et al. 2009). Based on a review of water requirements for waterbird breeding at Chowilla floodplain (Cale 2009), flow indicators specified primarily based on the water requirements of flood dependent vegetation communities are expected to be sufficient to support successful waterbird breeding. This is further supported by analysis undertaken of the relationship between flow thresholds and breeding attempts by colonial nesting birds at Lake Merriti which indicates that specified flow indicators are adequate to initiate waterbird breeding at this site. Breeding attempts by Australian White and Straw‐necked Ibis in Lake Merriti was found to be closely related to maximum flows of 25,000‐ 35,000 ML/d in the river upstream of the lake (Overton et al. 2009). Overton et al. (2009) suggests that for successful breeding, colonial nesting waterbirds require 4–5 months of flooding in total, taking into account provision of breeding cues and time needed to lay and incubate eggs and fledge young. In contrast to other sites within the Basin, at Lake Merreti the number of days exceeding a particular flow appears less important than flow threshold, which may be explained by the lake being a natural deflation basin and although regulated now, can (and used to naturally) hold water for an extended period after inundation (Overton et al. 2009). Given that wetlands at Riverland‐Chowilla are known to retain water for long periods after flows recede it is not considered necessary to provide long duration flow events to support successful waterbird breeding.
Two key factors dictate that waterbirds do not need to breed every year on the same river system (Scott 1997). Firstly, Australian waterbirds are highly mobile and their mobility over large spatial scales is a defining characteristic (Scott 1997; Overton et al. 2009). Most of the 80 odd species of (non‐vagrant) Murray‐Darling Basin waterbirds that use inland wetlands have broad Australia‐wide distributions and it is believed that individuals of most species are capable of dispersing at the scale of the continent (Overton et al. 2009). As such, prior to river regulation at least some individuals of
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the more mobile waterbird species have would have been able to seek suitable conditions for successfully breeding somewhere within the Basin in most years (Scott 1997).
Secondly, it is not essential for waterbirds to breed every year to maintain sustainable populations as they are generally long‐lived (Scott 1997). Waterbirds become sexually mature at the age of one to two years and have a life expectancy ranging generally from 3‐4 years for ducks, up to 8 years for larger birds such as ibis (Scott 1997).
These two key factors have informed the frequency of events for site‐specific flow indicators intended to support the habitat requirements of waterbirds, including provision of conditions conducive to successful breeding of colonial nesting waterbirds. Specifically, it is desirable to provide multiple opportunities for successful waterbird breeding within the range of their life expectancy. The proposed successful breeding of colonial nesting waterbirds at the Living Murray icon site in a minimum of three temporary wetlands and at a frequency of at least once every three years (MDBC 2006) is consistent with this rationale.
5.2.3. Native fish
The anabranch environments present within the Riverland‐Chowilla Floodplain have been identified as supporting significant populations of native fish, including provision of valuable habitat for conservationally significant Murray cod (Zampatti et al. 2008; Newall et al. 2009; Zampatti et al. 2011). Flow indicators have been developed for the Lower River Murray (expressed as flow to South Australia) for the in‐channel fresh element of the flow regime (separate report in preparation). The aim of the in‐channel fresh indicators is to inundate key habitat features and maintain healthy populations of native fish species. There is still debate in the scientific literature as to the relative role of flooding to fish community dynamics, and an understanding of the nature of ‘fish ecology’‐‘river flow’ interactions is by no means clear (Humphries et al. 1999, Mallen‐Cooper and Stuart 2003, Graham and Harris 2004; King et al. 2009). For example, it has been suggested that some fish species, such as Golden perch (Macquaria ambigua ambigua) and the conservationally significant Silver perch (Bidyanus bidyanus), which have been recorded at Riverland‐Chowilla Floodplain, require flow pulses or floods for spawning i.e. flood recruitment hypothesis (Humphries et al. 1999). This is partly supported by King et al. (2009) which suggest that flow is one environmental variable, although not always the key environmental variable, identified explaining the occurrence and abundance of spawning of Golden Perch, Silver Perch and Murray Cod at Barmah‐Millewa Forest. Other factors such water temperature and day length, or the interaction of a range of environmental variables including flow, are suggested to also be important for native fish recruitment (King et al. 2009). Despite the ongoing debate regarding the link between hydrology and fish ecology, available evidence supports that provision of flows that connect the river channel to the floodplain as well as in‐channel flow variability are important to sustaining key ecological features such as native fish populations. Flow indicators described herein for the bankfull and overbank elements of the flow regime primarily based on the water requirements of flood dependent vegetation communities and waterbirds are expected to be sufficient to support life‐cycle and habitat requirements of native fish including provision of cues for spawning and migration and access to food sources.
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5.2.4. Other biota
There are numerous studies concerning the water requirements of flood‐dependent vegetation communities and colonial nesting waterbirds of the Riverland‐Chowilla Floodplain and to a less degree the water requirements of native fish communities are also known. The understanding of flow‐ecology relationships of other faunal groups generally has more uncertainty owing to the reduced number of studies undertaken for these species. The MDBA is confident that the site‐ specific flow indicators determined to achieve the ecological targets relating to the current extent of native vegetation communities and the habitat requirements for waterbirds will also have valuable beneficial effects on the life‐cycle and habitat requirements of native fish, amphibians, and water‐ dependent reptiles and invertebrates (see Section 5.2.3. for description of expected benefits in terms of native fish populations). Key ecosystem functions associated with river and floodplain connectivity will also be enhanced.
5.2.5. Environmental works
Environmental works at the Riverland‐Chowilla Floodplain and Lindsay–Mulcra‐Wallpolla Islands (built, under construction and/or proposed as part of the Living Murray Program) could assist with meeting environmental outcomes through the delivery of water through works instead of through the delivery of high flows. For example, works will be able to be used to extend the duration of flooding in parts of the Riverland‐Chowilla Floodplain (i.e. those parts within the command of the works). The effect of using the works both at this site and for the broader River Murray environmental assets needs further assessment and consideration of the trade‐offs: Riverland Chowilla Floodplain and Lindsay–Mulcra‐Wallpolla Islands may be able to be managed with less water to meet many of the same outcomes but if flows associated with outcomes that can be delivered by works are removed this could be detrimental to achieving environmental outcomes at sites outside of the command of the works. As such, the MDBA has not currently reworked the flow indicators to take account of the works being built at Riverland‐Chowilla Floodplain. The implications of doing this, including tradeoffs with other parts of the river, needs further assessment and will input into a future Basin Plan review.
5.2.6. Proposed flow indicators
The site‐specific flow indicators for Riverland‐Chowilla Floodplain set out in Table 3 represent an amalgam of information from existing literature and River Murray floodplain inundation modelling data, checked against an analysis of modelled flows under without development and baseline conditions. Site‐specific flow indicators are expressed at River Murray South Australian border which generally represent flows for the entire Riverland‐Chowilla Floodplain hydrologic indicator site. Flow indicators as specified for the bankfull and overbank elements of the flow regime attempt to strike a balance between desirable flow threshold, duration and timing with desirable frequency and represent a variable flow regime that is consistent with the “without development” hydrology of the site. Where a discrepancy exists between the literature and inundation/hydrology modelling, an analysis of modelled without development flows has been used to guide the determination of site‐ specific flow indicators, particularly to ensure that the recommended flows are achievable and not greater than without development flows. This is particularly relevant to the Riverland‐Chowilla
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Floodplain where a number of inconsistencies between desired environmental water requirements and modelled without development flows were identified. The site‐specific flow indicators needed to achieve ecological targets for Riverland‐Chowilla Floodplain should be read in their entirety to understand the environmental water requirements as multiple flow indicators will contribute to achieving each ecological target. This approach has been used because it is not possible to define a single flow threshold for each vegetation community. The flood dependent vegetation communities cover a wide range of flows (Figure 3 and Figure 4) and a single indicator would be misleading. As an example, Cale (2009) reports that depending on their location on the floodplain, river red gum forest and woodland communities require flows between 5,000 to 70,000 ML/d. Floodplain inundation modelling further supports this by indicating that flows of approximately 5,000 ML/d will inundate these river red gum forest and woodland communities but flows in excess of 100,000 ML/d are required to inundate the full extent (Overton et al. 2006; Newall et al. 2009; DWLBC 2010). During the development of environmental water requirements for the Riverland‐Chowilla Floodplain hydrological indicator site it became apparent that the recommended flow indicators and inundation requirements specified within existing literature are often inconsistent with the modelled without development flow data (this is not uncommon). For example, Newall et al. (2009) recommended a flow of 50,000 ML/d for four months for river red gum forest and woodlands; and the recommended frequency for the short‐term limit of acceptable change is 1 in 3 years (33%), while the long‐term limit of acceptable change is 7–9 years in 10 (70–90%). Depending on assumptions, MDBA analysis shows this flow regime occurred 39 times in the 113 years (35% of years) under without development conditions. Similarly, Newall et al. 2009 suggested that to inundate 80% of black box communities requires flows in the order of 250,000 ML/d. However, as shown in Figure 5, modelled without development and baseline flow data shows only one of these events occurred in 114 years. Flows above about 140,000 ML/d are very infrequent, occurring 9 times in 114 years, or on average 1 in 12 years. This is at the very edge of the flooding requirements of black box, as reported in texts such as Roberts and Marston (2011) and those compiled by Cale (2009). These observations may reflect: inaccuracies in the analysis of flood thresholds to inundate vegetation communities on the floodplain; inaccuracies in MDBA modelling predictions of large floods; that vegetation at these higher elevations is supported by flooding (perhaps for recruitment) but flooding is less important for ongoing tree survival; and that vegetation at these higher elevations is sustained by water from groundwater interactions associated with flood events (rather than direct inundation), or from rainfall. In a review of black box watering requirements, Cale (2009) identifies that they use groundwater and rain‐derived water. This is consistent with black box being ecologically flexible and an opportunistic user of water (Roberts and Marston 2011).
The environmental water requirements for Riverland‐Chowilla Floodplain within the DWLBC (2010) report and CSIRO (2011) report have also been identified to contain a number of recommendations that exceed modelled without development conditions, both in terms of frequency and maximum period between events.
14
300,000 (ML/d)
250,000 Australia
200,000 South
to 150,000 flow
100,000 monthly
50,000 Maximim
0 1895 1899 1903 1907 1910 1914 1918 1922 1926 1930 1933 1937 1941 1945 1949 1953 1956 1960 1964 1968 1972 1976 1979 1983 1987 1991 1995 1999 2002 2006 without development baseline
Figure 5 Modelled without development and baseline flows to South Australia, 1895–2009 (based on MDBA analysis).
It is not possible to determine the exact reason for this inconsistency, but the flow indicators adopted by MDBA have taken this issue into account by limiting some flow recommendations outlined in the literature to ensure they do not exceed modelled without development flows. This approach is consistent with the overall objective to achieve a healthy working Murray‐Darling Basin. For example, the highest flow magnitude indicator proposed for the Riverland‐Chowilla floodplain is to provide a flow of 125,000 ML/d for a maximum of 7 days. Although this flow regime is less than that recommended by Newall et al. 2009 it is still consistent with Cale’s (2009) black box requirements. These inconsistencies between literature and modelled flow data explain why the flow regime specified in Table 3 is not linked explicitly to any one document and is an amalgam of information and data analysis. Given the uncertainty regarding the importance of floods in maintaining black box woodlands at Riverland‐Chowilla Floodplain in a healthy, dynamic and resilient condition and limitations imposed by current operational constraints (see Section 6) the MDBA has not proposed flow indicators to inundate the entire current extent of black box woodlands. Generally, the flow indicator component with the greatest level of uncertainty across the Basin is the definition of the desirable frequency of inundation, expressed as the proportion of years an event is required. 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 across the floodplain and would have experienced significant variability in their inundation
15
frequency under pre‐development conditions which subsequently makes specification of a single frequency metric deceptively certain. For many species and ecological communities 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/community. Recognising the degree of confidence in specifying a desirable frequency, ‘low‐uncertainty’ and ‘high‐uncertainty’ frequency of flow events have been specified (Table 3). 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, may 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 indicate a level beyond which the ecological targets may not be achieved. For the Riverland‐Chowilla Floodplain a number of key sources of information were used to inform the high and low uncertainty frequencies. Site specific information, particularly the Riverland Ramsar Site Ecological Character Description (Newall et al. 2009) and a review of the Chowilla Floodplain’s flooding regime (Cale 2009), was complemented by more generic literature on water requirements of flood dependent vegetation communities, particularly Roberts and Marston (2011). These documents express the desired frequency as a range and the high and low uncertainty frequency flow indicator metrics attempt to encapsulate the broad water requirements represented by this range. Modelled flow data was used to verify if recommended frequencies were achievable and not greater than without development flows. Comparison of the proposed flow indicators with more recent documents, particularly DWLBC (2010) and CSIRO (2011), indicate that the desired frequency of events as specified in these documents are broadly consistent with MDBA’s proposed low uncertainty flow indicator frequencies. MDBA specifies frequency as a proportion of years over the entire modelling period of 114 years e.g. event occurs on average once every 5 years over the 114 year modelling period. Frequencies expressed in this way are consistent with the modelled without development hydrology. In contrast, frequencies in other documents are sometimes expressed on a year by year basis e.g. event occurs at least once every 5 years over the 114 year modelling period. MDBA analysis and CSIRO (2011) analysis both suggest that frequency expressed in this way would not have occurred under without development conditions as events are clustered according to climate variability and as such during drought periods the desired frequency would exceed without development flows. It is unclear whether the desired frequencies as reported in DWLBC (2010) and CSIRO (2011) are intended to be interpreted in the latter or former format. It is recognised that periods between inundation events are an important consideration when trying to determine ecosystem resilience or thresholds of irreversible change. When investigating the environmental water requirements for the various sites, consideration was given to specifying a maximum period between events or metrics related to maximum dry. However, the literature regarding the tolerance of various floodplain ecosystems to dry periods is limited. In addition where this information exists, recommended maximum dry intervals often conflicts with the maximum dry experienced under modelled without development conditions. This is highlighted by maximum time between events recommended for Riverland‐Chowilla (see DWLBC 2010; CSIRO 2011) which are
16
generally less than the without development maximum period between events based on analysis presented in CSIRO (2011) and MDBA’s own analysis. Considering these issues, MDBA has not proposed a maximum dry period with the exception of a small number of sites across the Basin, which does not include the Riverland‐Chowilla Floodplain. Even so, the importance of maximum dry periods and their role in maintaining ecosystem resilience is recognised. Maximum dry periods between successful events is reported for hydrological modelling associated with the Riverland‐Chowilla Floodplain hydrologic indicator site (see MDBA 2012) despite reducing the maximum period between events not being the primary objective of the modelling process.
17
Table 3 Site‐specific ecological targets and associated flow indicators for the Riverland‐Chowilla Floodplain.
Without development and Site-Specific Flow Indicators baseline event frequencies
Event Frequency – proportion of Proportion of Proportion of years event required years event years event Site-Specific Ecological Targets Flow required occurs under occurs under Low High (measured as modelled modelled uncertainty uncertainty flow to South Durationa Timing without baseline (%) (%) Australia) development conditions (ML/d) conditions (%) (%)
Provide a flow regime which ensures the current 40,000 30 days total (with 70 50–60 80 37 extent of native vegetation of the riparian, 7 day minimum) floodplain and wetland communities is sustained 90 days total (with in a healthy, dynamic and resilient condition 40,000 June to December 50 33 58 22 7 day minimum) Provide a flow regime which supports the habitat requirements of waterbirds and is conducive to 60,000 60 days total (with 33 25 41 12 successful breeding of colonial nesting 7 day minimum) waterbirds 30 days total (with Preferably winter/spring 80,000 25 17 34 10 Provide a flow regime which supports 7 day minimum) but timing not recruitment opportunities for a range of native constrained to reflect aquatic species (e.g. fish, frogs, turtles, 100,000 21 days total (with that high flows are 17 13 19 6 invertebrates) 1 day minimum) dependent on occurrence of heavy Provide a flow regime which supports key 7 days total (with rainfall and will be ecosystem functions, particularly those related to 125,000 13 10 17 4 1 day minimum) largely unregulated connectivity between the river and the floodplain events a Duration is expressed both as a total and minimum, allowing multiple smaller flow events that met the minimum duration criteria to comprise a successful event. Minimum durations are therefore a subset of total duration and should not be read independently. MDBA analysis showed that if a minimum duration is not specified individual events must meet the total duration criteria; this resulted in a significantly reduced proportion of years. Note: Multiplication of the flow rate by the duration and frequency (proportion of years event required) 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. Additional environmental water required is the amount over and above the baseline flows.
18
6. Flow delivery constraints
Basin wide environmental objectives have been developed within the context of being deliverable in a working river system that contains public and private storages and developed floodplains. To understand and assess the implications of key constraints on the ability to achieve flow indicators specified for the Riverland‐Chowilla Floodplain, MDBA has drawn upon a combination of existing information (e.g. Water Sharing Plans, operating rules of water agencies, flood warning levels) and practical knowledge of river operators supported by testing using hydrological modelling. Flows downstream of Hume Dam are typically limited to 25,000 ML/d under regulated flow conditions to minimise overbank flows and the associated inundation of agricultural land. This constraint prevents the release of flows, or adding water to top up or enhance natural flows, above 25,000 ML/d. Constraints within tributaries of the Murray, particularly the Lower Darling River, Goulburn River and Murrumbidgee River, also influence the ability to achieve flow indicators specified for Riverland‐ Chowilla Floodplain. Flooding and channel capacity constraints on regulated releases from Menindee Lakes in the Lower Darling, Lake Eildon in the Goulburn River and Burrinjuck and Blowering Dams in the Murrumbidgee River (see MDBA 2011 for further detail) will act in combination with constraints in the Murray system to limit achievement of some flow indicators. The MDBA has a vision of a healthy working Basin that has vibrant communities, productive and resilient industries, and healthy and diverse ecosystems. The delivery of environmental flows as a managed watering event within a healthy working Basin is highly dependent on existing system constraints, accordingly the site‐specific flow indicators have been classified into three broad types (Table 4). Consistent with this rationale, within the hydrological modelling process used by the MDBA to assess the achievement of site‐specific flow indicators orders for environmental flows have been limited to be within the constraints represented by the baseline model. This limits the delivery of regulated flows to the Riverland‐Chowilla Floodplain. Based on the information above, It is likely that the 90 day duration 40,000 ML/d site‐specific flow indicator and the 60,000 ML/d flow indicator at the South Australian Border will require the co‐ ordinated delivery of regulated releases from multiple systems (Murray, Lower Darling, Murrumbidgee and/or Goulburn systems). In some years, constraints are likely to impede the ability to co‐ordinate regulated releases to achieve the desired flow for the desired duration, and hence frequency, and will be reliant on supplementing tributary inflows with a regulated release from storage. Similarly, while the 80,000 ML/d flow indicator may be deliverable by supplementing tributary inflows with co‐ordinated regulated release it is considered likely that constraints will more significantly limit the ability to achieve the desired duration and frequency of this flow indicator. Without addressing a range of constraints, it is likely that the 100,000 ML/d and 125,000 ML/d Riverland‐Chowilla Floodplain indicators are not deliverable under current river operations and are beyond the scope of a managed watering event. The achievement of site‐specific ecological targets and flow indicators limited by constraints will be heavily reliant on large inflow events from a number of tributaries and potential storage spills.
Table 4: Site‐specific flow indicators for Riverland‐Chowilla Floodplain and the effect of system constraints
Site-specific ecological targets Site-specific flow indicators
Provide a flow regime which ensures the 40,000 ML/d for a total duration of 30 days (with a minimum duration of 7 current extent of native vegetation of the consecutive days) between June & December for 50% of years riparian, floodplain and wetland communities is sustained in a healthy, dynamic and resilient 40,000 ML/d for a total duration of 90 days (with a minimum duration of 7 condition consecutive days) between June & December for 33% of years Provide a flow regime which supports the habitat requirements of waterbirds and is 60,000 ML/d for a total duration of 60 days (with a minimum duration of 7 conducive to successful breeding of colonial consecutive days) between June & December for 25% of years nesting waterbirds 80,000 ML/d for a total duration of 30 days (with a minimum duration of 7 Provide a flow regime which supports consecutive days) anytime in the water year for 17% of years recruitment opportunities for a range of native aquatic species (e.g. fish, frogs, turtles and 100,000 ML/d for a total duration of 21 days anytime in the water year for 13% invertebrates) of years Provide a flow regime which supports key ecosystem functions, particularly those related 125,000 ML/d for a total duration of 7 days anytime in the water year for 10% to connectivity between the river and the of years floodplain
Key
Achievable under current operating conditions Flow indicators highlighted in blue are considered deliverable as mostly regulated flows under current operating conditions.
Achievable under some conditions (constraints limit delivery at some times) Flow indicators highlighted in yellow are considered achievable when delivered in combination with tributary inflows and/or unregulated flow events. They may not be achievable in every year or in some circumstances, and the duration of flows may be limited to the duration of tributary inflows.
Difficult to influence achievement under most conditions (constraints limit delivery at most times) Flow indicators highlighted in brown require large flows that cannot be regulated by dams and it is not expected that these flows can currently be influenced by river operators due to the river operating constraints outlined above.
7. Summary and conclusion
The Riverland‐Chowilla Floodplain is a key environmental asset within the Basin and is an important site for the determination of the environmental water requirements of the Basin. MDBA has undertaken a detailed eco‐hydrological assessment of Riverland‐Chowilla Floodplain environmental 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 Riverland‐Chowilla Floodplain and for the broader river valley and reach. Along 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 including consideration of a range of constraints such as those outlined in Section 6 is described in further detail within 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 Riverland‐Chowilla Floodplain.
References Cale, B 2009, Literature review of the current and historic flooding regime and required hydrological regime of ecological assets on the Chowilla Floodplain, report for South Australian Murray–Darling Basin Natural Resources Management Board, Murray Bridge, South Australia. Carpenter, G 1990, ‘Avifauna’, in C O’Malley & F Sheldon (eds), Chowilla Floodplain biological study, Nature Conservation Society of South Australia, Adelaide. CSIRO 2008, Water availability in the Murray, a report to the Australian Government from the CSIRO Murray–Darling Basin Sustainable Yields Project, CSIRO, Australia. CSIRO 2011, A science review of the implications for South Australia of the Guide to the proposed Basin Plan: synthesis, Godyer Institute for Water Research, Adelaide, Australia. Department of the Environment, Water, Heritage and the Arts 2001, A directory of important wetlands in Australia, Australian wetlands database — spatial data, viewed November 2008,
Humphries, P, King, AJ and Koehn, JD 1999, ‘Fish, flows and flood plains: links between freshwater fishes and their environment in the Murray‐Darling River system, Australia’. Environmental Biology of Fishes 56, 129‐151. King, AJ, Ramsey, D, Baumgartner, L, Humphries, P, Jones, M, Koehn, J, Lyon, J, Mallen‐Cooper, M, Meredith, S, Vilizzi, L, Ye, Q & Zampatti, B 2009, Environmental requirements for managing successful fish recruitment in the Murray River Valley – Review of existing knowledge, Arthur Rylah Institute for Environmental Research Technical Report Series No. 197, Department of Sustainability and Environment, Heidelberg.
Mallen‐Cooper, M & Stuart, IG 2003, ‘Age, growth and non‐flood recruitment of two potamodromous fishes in a large semi‐arid/temperate river system’. River research and applications 19: 697‐719.
MDBA (Murray‐Darling Basin Authority) 2011, The proposed “environmentally sustainable level of take” for surface water of the Murray‐Darling Basin: Method and Outcomes. Murray‐Darling Basin Authority, Canberra. MDBA (Murray‐Darling Basin Authority) 2012, Hydrologic modelling to inform the proposed Basin Plan: Methods and results, MDBA, Canberra.
MDBC (Murray–Darling Basin Commission) 2006, The Chowilla Floodplain and Lindsay–Wallpolla Islands icon site environmental management plan, MDBC, Canberra. Newall, P, Lloyd, L, Gell, P & Walker, K 2009, Riverland Ramsar site ecological character description, SA Department of Environment and Heritage, Adelaide. NSW Department of Environment, Climate Change and Water 2009, Atlas of NSW wildlife, viewed October 2009,
SKM (Sinclair Knight Merz) 2007, High Conservation Value Aquatic Ecosystems project ‐ identifying, categorising and managing HCVAE, Final report, Department of the Environment and Water Resources, 16 March 2007,
Appendix A
Data used in producing hydrologic indicator site maps
Data Dataset name Sourcea Basin Plan regions Draft Basin Plan Areas 25 May 2010 Murray–Darling Basin Authority (2010) Dam GEODATA TOPO 250K Series 3 Geoscience Australia 2006 walls/barrages Topographic Data Gauges 100120 Master AWRC Gauges Icon sites Living Murray Indicative Icon Site Murray–Darling Basin Commission (2007) Boundaries Irrigation areas Combined Irrigation Areas of Bureau of Rural Sciences (2008) Australia Dataset Lakes GEODATA TOPO 250K Series 3 Geoscience Australia (2006) Topographic Data Maximum wetland Wetlands GIS of the Murray–Darling Murray–Darling Basin Commission (1993) extents Basin Series 2.0 (Kingsford) National Digital Cadastral Database New South Wales Department of Lands (2007) parks/nature reserves National Collaborative Australian Protected Department of the Environment, Water, Heritage and the Arts parks/nature Areas Database — CAPAD 2004 (2004) reserves Nationally Directory of Important Wetlands in Department of the Environment, Water, Heritage and the Arts important wetlands Australia Spatial Database (2001) Ocean and GEODATA TOPO 250K Series 3 Geoscience Australia (2006) landmass Topographic Data Ramsar sites Ramsar wetlands in Australia Department of the Environment, Water, Heritage and the Arts (2009) Rivers Surface Hydrology (AUSHYDRO Geoscience Australia (2010) version 1-6) Roads GEODATA TOPO 250K Series 3 Geoscience Australia (2006) Topographic Data State border GEODATA TOPO 250K Series 3 Geoscience Australia (2006) Topographic Data State forests Digital Cadastral Database New South Wales Department of Lands (2007) Towns GEODATA TOPO 250K Series 3 Geoscience Australia (2006) Topographic Data Weirs Murray–Darling Basin Weir Murray–Darling Basin Commission (2001) Information System 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.
Appendix B
Species relevant to criteria 1 and 4: Riverland‐Chowilla Floodplain
Species Recognised Environment Fisheries Threatened Flora and National Fisheries in Protection Management species Fauna Parks Management international and Act 2004 conservation Guarantee and Act 2007 agreement(s) Biodiversity (NSW) Act 1995 Act 1998 Wildlife (SA)2 1 Conservatio (NSW) (VIC) Act 1972 n Act 1999 (SA)2 (Cwlth)
Amphibians and reptiles
Beaked gecko (Rhynchoedura ornata)6 CE
Broad-shelled tortoise (Chelodina E V expansa)5,6 Carpet python (Morelia spilota E R metcalfei)4,67 Lace monitor (Varanus varius)6 R
Mueller's skink (Lerista muelleri)6 E
Murray tortoise (Emydura macquarii)5 L
Port Lincoln snake (Suta spectabilis)6 V
Red-naped snake (Furina diadema)6 V
Southern bell or growling grass frog V L E V (Litoria raniformis)3, 5, 6 Striped legless lizard (Delma impar)6 V E
Birds Australasian bittern (Botaurus V E V poiciloptilus)5 Australasian darter (Anhinga R novaehollandiae)6 Australasian shoveler (Anas rhynchotis)6 R
Australian pied oystercatcher R (Haematopus longirostris)6 Banded stilt (Cladorhynchus V leucocephalus)5, 6 Barking owl (Ninox connivens)6 V E R
Blue-billed duck (Oxyura australis)5, 6 V E R
Blue bonnet (Northiella haematogaster)6 E R
Blue-faced honeyeater (Entomyzon R cyanotis)5, 6 Blue-winged parrot (Neophema V chrysostoma)6 Brolga (Grus rubicunda)6 V V
Bush stone-curlew (Burhinus grallarius)5, E R 6
Species Recognised Environment Fisheries Threatened Flora and National Fisheries in Protection Management species Fauna Parks Management international and Act 2004 conservation Guarantee and Act 2007 agreement(s) Biodiversity (NSW) Act 1995 Act 1998 Wildlife (SA)2 1 Conservatio (NSW) (VIC) Act 1972 n Act 1999 (SA)2 (Cwlth)
Caspian tern (Sterna caspia)4 NT
Chestnut-rumped heathwren (Hylacola V ssp pyrrhopygia)6 Curlew sandpiper (Calidris ferruginea)4 ssp
Eastern great egret (Ardea modesta)4, 6 V V
Freckled duck (Stictonetta naevosa)5, 6 V E V
Gilbert's whistler (Pachycephala V R inornata)6 Glossy ibis (Plegadis falcinellus)5, 6 R
Great crested grebe (Podiceps R cristatus)5, 6 Greenshank (Tringa nebularia)4
Grey currawong (Strepera versicolor)6 ssp
Grey-crowned babbler (Pomatostomus V E temporalis temporalis)6 Gull-billed tern (Gelochelidon nilotica)6 E
Hooded robin (Melanodryas cucullata)6 V NT ssp
Intermediate egret (Ardea intermedia)5,6 CE R
Jacky winter (Microeca fascinans)6 ssp
Little egret (Egretta garzetta)6 E R
Little friar bird (Philemon citreogularis)5, 6 R
Major Mitchell’s cockatoo (pink cockatoo) V V R (Lophochroa leadbeateri)5, 6 Malleefowl (Leipoa ocellata)6 V E E V
Musk duck (Biziura lobata)5, 6 CE R
Olive-backed oriole (Oriolus sagittatus)6 R
Orange-bellied parrot (Neophema CE E chrysogaster)6 Pacific golden plover (Pluvialis fulva)6 R
Pectoral sandpiper (Calidris melanotos)6 R
Peregrine falcon (Falco peregrinus)6 R
Red-chested button-quail (Turnix V pyrrhothorax)6 Red-necked stint (Calidris ruficollis)4
Species Recognised Environment Fisheries Threatened Flora and National Fisheries in Protection Management species Fauna Parks Management international and Act 2004 conservation Guarantee and Act 2007 agreement(s) Biodiversity (NSW) Act 1995 Act 1998 Wildlife (SA)2 1 Conservatio (NSW) (VIC) Act 1972 n Act 1999 (SA)2 (Cwlth)
Regent parrot (eastern) (Polytelis V E V ssp anthopeplus monarchoides)3, 6 Restless flycatcher (Myiagra inquieta)6 R
Ruddy turnstone (Arenaria interpres)6 R
Scarlet robin (Petroica boodang)6 ssp
Scarlet-chested parrot (Neophema R splendida)6 Sharp-tailed sandpiper (Calidris acuminate)4 Square tailed kite (Lophoictinia isura)5 V V
Striped honeyeater (Plectorhyncha R lanceolata)5, 6 White-bellied sea-eagle (Haliaeetus V E leucogaster)5, 6 White-winged chough (Corcorax R melanorhamphos)6 Wood sandpiper (Tringa glareola)6 R
Fish
Freshwater catfish (Tandanus tandanus)5 E E E P
Murray cod (Maccullochella peelii peelii)3, V E E 4 Murray hardyhead (Craterocephalus V CE CE CE fluviatilis)3, 4 Silver perch (Bidyanus bidyanus)4 V CE E P
Southern pigmy perch (Nannoperca E E P australis)4 Trout cod (Maccullochella E E CE EX P macquariensis)4 Unspecked hardyhead (Craterocephalus L R sterusmuscarum flvus)4 Mammals Feathertailed glider (Acrobates E pygmaeus)4, 6 Common brushtail possum (Trichosurus R vulpecula)6 Little pied bat (Chalinolobus picatus)6 E
Plant Australian broomrape (Orobanche R cernua var. Australiana)6 Barren cane-grass (Eragrostis R infecunda)6 Behr's swainson-pea (Swainsona V behriana)6
Species Recognised Environment Fisheries Threatened Flora and National Fisheries in Protection Management species Fauna Parks Management international and Act 2004 conservation Guarantee and Act 2007 agreement(s) Biodiversity (NSW) Act 1995 Act 1998 Wildlife (SA)2 1 Conservatio (NSW) (VIC) Act 1972 n Act 1999 (SA)2 (Cwlth)
Bignonia emu-bush (Eremophila V bignoniiflora)6 Black cotton-bush (Maireana decalvans)6 E
Black-fruit daisy (Brachyscome V melanocarpa)6 Creeping boobialla (Myoporum R parvifolium)6 Cyperus (Cyperus nervulosus)6 R
Dainty maiden-hair (Adiantum capillus- V veneris)6 Darling lily (Crinum flaccidum)6 V
Desert spurge (Euphorbia tannensis E eremophila)6 Frankenia (Frankenia cupularis)6 R
Hairy darling-pea (Swainsona greyana)6 E
Hoary scurf-pea (Cullen cinereum)6 E
Jagged bitter-cress (Rorippa laciniata)6 R
Matted water starwort (Callitriche R sonderi)6 Nutty club-rush (Isolepis producta)5 V
Pale beauty-heads (Calocephalus R sonderi)5, 6 Pale flax-lily (Dianella porracea)6 V
Pale-fruit cherry (Exocarpus strictus)5, 6 R
Plains spurge (Euphorbia planiticola)6 E
Poison pratia (Pratia concolor)6 R
Purple crassula (Crassula peduncularis)5, R 6 Purple love-grass (Eragrostis lacunaria)6 R
Robust milfoil (Myriophyllum papillosum)5, R 6 Shade peppercress (Lepidium V pseudotasmanicum)6 Silver saltbush (Atriplex rhagodioides)6 V
Slender fissure-plant (Maireana R pentagona)5, 6 Small monkey-flower (Mimulus R prostratus)6 Small-flower beetle-grass (Diplachne R parviflora)6
Species Recognised Environment Fisheries Threatened Flora and National Fisheries in Protection Management species Fauna Parks Management international and Act 2004 conservation Guarantee and Act 2007 agreement(s) Biodiversity (NSW) Act 1995 Act 1998 Wildlife (SA)2 1 Conservatio (NSW) (VIC) Act 1972 n Act 1999 (SA)2 (Cwlth)
Spiny lignum (Muehlenbeckia horrida R horrida)6 Spreading goodenia (Goodenia R heteromera)6 Squat picris (Picris squarrosa)5, 6 R
Stalked brooklime (Gratiola R pedunculata)6 Swamp daisy (Brachycome basaltica var. R gracilis)5, 6 Tufted burr-daisy (Calotis scapigera)5, 6 R
Upright milfoil (Myriophyllum crispatum)5, V 6 Water starwort (Callitriche umbonata)5, 6 V V
Waterwort (Elatine gratioloides)5, 6 R
Wavy marshwort (Nymphoides crenata)5, R 6 Zannichellia (Zannichellia palustris)6 R
CE = critically endangered DD = data deficient E = endangered EP = endangered population EX = extinct L = listed NT = near threatened P = protected R = Rare SSP = threatened at the sub‐specific level2 V = vulnerable
1 Japan–Australia Migratory Bird Agreement, China–Australia Migratory Bird Agreement, or Republic of Korea – Australia Migratory Bird Agreement
2 ssp = The threatened status applies at the subspecific level; however, the database record is at the species level. For completeness these records are retained but expert interpretation is required for this record to resolve subspecific taxonomy.
3 Murray–Darling Basin Commission (2006)
4 SA Department of Water, Land and Biodiversity Conservation (2009)
5 Newall et al. (2009)
6 NSW Department of Environment, Climate Change and Water (2009), SA Department for Environment and Heritage (2009), Victorian Department of Sustainability and Environment (2009)