Kerang Lakes Bypass
Investigation Project Technical Report
THIRD REEDY LAKE
PREPARED FOR THE GOULBURN-MURRAY WATER CONNECTIONS PROJECT
OCTOBER 2014 Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
DOCUMENT HISTORY AND STATUS Version Date Issued Prepared By Reviewed By Date Approved Version 1 31 May 2013 Bree Bisset Rohan Hogan, Michelle Maher, Louissa 4 June 2013 Rogers, Emer Campbell and Trent Gibson Version 2 5 June 2013 Bree Bisset, Michelle Maher Rohan Hogan and Louissa Rogers 7 June 2013 Version 3 17 June 2013 Bree Bisset, Michelle Maher KLBIP Project Reference Group 1 July 2013 Version 4 2 August 2013 Bree Bisset, Michelle Maher Louissa Rogers 2 August 2013 Version 5 2 August 2013 Bree Bisset, Michelle Maher KLBIP Project Reference Group TBC Version 6 21 August 2013 Bree Bisset, Michelle Maher G-MW CP ERP 26 August 2013 Version 7 4 September 2013 Bree Bisset, Michelle Maher G-MW CP SRP 25 September 2013 Version 8 4 October 2013 Bree Bisset, Michelle Maher G-MW CP ERP TBC Version 9 5 November 2013 Bree Bisset, Michelle Maher Final draft TBC Version 10 12 December 2013 Bree Bisset Rohan Hogan 14 January 2014 Version 11 14 January 2014 Bree Bisset , Rohan Hogan G-MW CP – Pat Feehan Version 12 7 October 2014 Bree Bisset , Rohan Hogan DISTRIBUTION Version Date Quantity Issued To Version 1 31 May 2013 Email Rohan Hogan, Michelle Maher, Louissa Rogers, Emer Campbell and Trent Gibson Version 2 5 June 2013 Internal review Rohan Hogan and Louissa Rogers Version 3 17 June 2013 Email Pat Feehan (G -MW) Version 4 2 August 2013 Email Louissa Rogers Version 5 2 August 2013 Email Pat Feehan (G -MW) Version 6 21 August 2013 Email G-MW CP ERP Version 7 4 September 2013 Email/ Hard copies G-MW CP SRP Version 8 4 October 2013 Email / Hard copy G-MW CP ERP Version 9 5 November 2013 Email G-MW CP – Pat Feehan Version 10 12 December 2013 Email Rohan Hogan Version 11 14 January 2014 Email G-MW CP – Pat Feehan Version 12 7 October 2014 Email G-MW CP – Pat Feehan DOCUMENT MANAGEMENT
Printed: 8 October 2014
Last saved: 8 October 2014 11:07 AM
File name: KLBIP Third Reedy Lake Technical Report
Authors: Bree Bisset, Michelle Maher, Rohan Hogan
Name of organisation: North Central CMA Name of document: KLBIP Technical Report – Third Reedy Lake Document version: Version 12
Document manager: NCCMA-63-30448
For further information on any of the information contained within this document contact: North Central Catchment Management Authority PO Box 18 Huntly Vic 3551 T: 03 5440 1800 F: 03 5448 7148 E: [email protected] www.nccma.vic.gov.au © North Central Catchment Management Authority, 2014 Front cover photo: Third Reedy Lake, August 2011, Michelle Maher, North Central CMA The Kerang Lakes Bypass Investigation Project Technical Report - Third Reedy is a working document, compiled from the best available information. It will be subject to revision in the future as new information becomes available. This publication may be of assistance to you, but the North Central Catchment Management Authority and its employees do not guarantee that the publication is without flaw of any kind, or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on information in this publication. Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
Please cite this document as: North Central CMA (2014). Kerang Lakes Bypass Investigation Project Technical Report – Third Reedy Lake, North Central Catchment Management Authority, Huntly. Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
EXECUTIVE SUMMARY
The Kerang Lakes Bypass Investigation Project (KLBIP) investigates the feasibility of constructing bypass channels around the Reedy Lakes Complex (comprising First, Middle and Third Reedy Lakes), Little Lake Charm and Racecourse Lake. The project, which is part of Goulburn-Murray Water’s (G-MW) Business Case to support Stage 2 of the G-MW Connections Project, aims to remove irrigation demand and develop a variable water regime that will enhance wetland environmental values. Third Reedy Lake is a 230 ha permanent open freshwater lake located approximately ten kilometres north- west of Kerang. The wetland is part of the Kerang Lakes Ramsar Site and is the most northerly wetland in the Reedy Lakes Complex. The permanent operation of Third Reedy Lake since the 1920s has altered the values of the wetland significantly. The small band of littoral vegetation, low species diversity and high weediness is a result of the prolonged stable water levels. However the wetland still provides habitat for a range of flora and fauna species listed under various international, national and Victorian state legislations including species listed under the Environment Protection and Biodiversity Conservation Act 1999. Third Reedy Lake has also supports a small rookery of Australian White Ibis and Straw-necked Ibis on its northern shore. Background information, hydrogeological assessments, flora and fauna surveys as well as technical input was used to determine the preferred environmental water management goal and appropriate water regime for Third Reedy Lake as summarised below:
Management goal Provide a watering regime that restores Third Reedy Lake to a deep freshwater marsh (dominated by Intermittent Swampy Woodland (EVC 813)) able to support recruitment of River Red Gums ( Eucalyptus camaldulensis ) and promoting a diverse and extensive range of habitat suitable for a variety of
waterbirds.
Preferred regime Establishment phase: A filling regime that provides opportunities for River Red Guns to establish across the wetland by allowing for seed release, seed strike and establishment of seedlings. The regime will include filling wetland to between 74.2m-74.56m AHD and allowing wetland to dry by natural drawdown. When appropriate this will be followed by a series of low level fills (approximately 0.3m to 0.5m deep) to encourage establishment of River Red Gums. The establishment phase will require adaptive management depending on the response from River Red Gum recruitment. This regime should be followed for two to three cycles or until desirable number of saplings have established. Long term management: Providing a watering regime that returns Third Reedy Lake to a deep freshwater marsh dominated by River Red Gums ( Eucalyptus camaldulensis ) with a sedge and lignum understory and fringing Black Box (Eucalyptus largiflorens ) community. Fill once every four years to 74.00m AHD with every third fill to 74.56m AHD. Maintain at 74.56m AHD for one month duration to maintain Black Box and recruited River Red Gums. For other events fill to 74.00m AHD to maintain recruited River Red gums and support
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lignum and sedge community and allow natural drawdown with wetland rema ining dry for the following three years before filling again. Adaptive management is required to ensure the salinity tolerances of ecological objectives i.e. River Red Gum, are not exceeded. This Technical Report also assesses the associated benefits and risks and proposes mitigation strategies required to manage the wetland under the preferred regime. This report also provides a number of recommendations to address key knowledge gaps associated with the project.
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CONTENTS PAGE
EXECUTIVE SUMMARY ...... I CONTENTS PAGE ...... III LIST OF FIGURES ...... V LIST OF TABLES ...... V ACKNOWLEDGEMENTS ...... VI 1. GOULBURN-MURRAY WATER CONNECTIONS PROJECT ...... 1 2. PURPOSE AND SCOPE OF DOCUMENT ...... 1 3. BACKGROUND ...... 2
3.1. RAMSAR CONVENTION ...... 4 4. THIRD REEDY LAKE ...... 7
4.1. BACKGROUND ...... 7 5. WATER DEPENDENT VALUES ...... 8
5.1. LISTING AND SIGNIFICANCE ...... 8 5.2. FLORA ...... 8 5.3. FAUNA ...... 12 5.4. REPRESENTATIVENESS AND DISTINCTIVENESS ...... 14 5.5. THIRD REEDY LAKE IN THE RAMSAR CONTEXT ...... 14 6. HYDROLOGY ...... 15
6.1. NATURAL REGIME ...... 15 6.2. HISTORIC /CURRENT WATER MANAGEMENT ...... 16 6.3. TRAJECTORY FOR THE ENVIRONMENTAL VALUES OF THIRD REEDY LAKE UNDER CURRENT WATER REGIME ...... 16 6.4. ALTERNATIVE WATER REGIME SCENARIOS FOR THIRD REEDY LAKE ...... 17 6.5. ADDITIONAL ANALYSIS OF ALTERNATIVE WATER SCENARIOS FOR THIRD REEDY LAKE ...... 20 6.6. GROUNDWATER ASSESSMENT ...... 20 6.7. ADDITIONAL GROUNDWATER ASSESSMENT ...... 22 7. RATIONALE FOR RECOMMENDED WATER REGIME ...... 23 8. MANAGEMENT OBJECTIVES...... 26
8.1. MANAGEMENT GOAL ...... 27 8.2. ECOLOGICAL AND HYDROLOGICAL OBJECTIVES ...... 27 8.3. PROPOSED WATER REGIME ...... 28 9. POTENTIAL RISK, ADVERSE IMPACTS AND BENEFITS ...... 33
9.1. IMPACT TO CURRENT RAMSAR CRITERIA ...... 33 9.2. RISK AND BENEFIT ASSESSMENT ...... 33 9.3. MITIGATION ASSESSMENT ...... 46 9.4. RISK AND MITIGATION SUMMARY ...... 54 10. KNOWLEDGE GAPS ...... 54 11. REFERENCES ...... 55 APPENDIX A: BATHYMETRY ...... 59 APPENDIX B: 2013 EVC MAPPING ...... 62 APPENDIX C: FLORA AND FAUNA SPECIES LIST ...... 63 APPENDIX D: WATER REQUIREMENTS OF ECOLOGICAL VALUES ...... 68
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APPENDIX E: WATER REGIME SUMMARIES ...... 71
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LIST OF FIGURES
Figure 1 : KLBIP development process ...... 2 Figure 2: KLBIP Location Map ...... 3 Figure 3: Map of the Kerang Wetland Ramsar Site ...... 5 Figure 4: Map of Third Reedy Lake including key features...... 7 Figure 5: A conceptual cross section of Third Reedy Lake showing current conditions. Insert map shows cross section position (image not to scale)...... 9 Figure 6: A conceptual model of the littoral zone of Third Reedy Lake as marked in Figure 5 (red) under current regime...... 10 Figure 7: Predicted water levels under each proposed regime (Gippel, 2013) ...... 19 Figure 8: Predicted water levels and percentage of bed dry under updated and preferred regime (Gippel, 2014) ... 20 Figure 9: Bore Hydrograph: Nested Site 58533/58554 ...... 22 Figure 9: A conceptual cross section of Third Reed Lake under proposed regime. Insert map shows cross section position (image not to scale)...... 31 Figure 10: A conceptual model of the littoral zone of Third Reedy Lake as marked in Figure 9 (red) under proposed regime...... 32
LIST OF TABLES
Table 1: Kerang Wetlands Ramsar site satisfied criteria (KBR, 2011) ...... 6 Table 2: Relevant legislation, agreements, convention and listings recorded in Third Reedy Lake ...... 8 Table 3: Current EVCs within Third Reed Lake and their bioregional conservation status (Rakali, 2013) ...... 8 Table 4: Significant flora species recorded at Third Reedy Lake ...... 11 Table 5: Bird breeding events at Third Reedy Lake since 1988 ...... 12 Table 6: Significant fauna species recorded at Third Reedy Lake ...... 13 Table 7: Current area of Permanent Open water across the landscape ...... 14 Table 8: Third Reedy Lake against Ramsar Criteria ...... 15 Table 9: Third Reedy Lake water level percentiles (June 1986 to July 2013) ...... 16 Table 10: Third Reedy Lake wetting/drying calendar ...... 16 Table 11: Third Reedy Lake proposed watering regime scenarios (North Central CMA, 2012) ...... 17 Table 12: Third Reedy Lake modelling results (Gippel, 2012) ...... 17 Table 13: Third Reedy Groundwater Risk Assessment (URS, 2013) ...... 21 Table 13: Updated Third Reedy Groundwater Risk Assessment (URS, 2014) ...... 23 Table 14: Risk assessment associated with each watering regime scenario at Third Reedy Lake ...... 26 Table 15: Previous management considerations ...... 26 Table 16: Proposed ecological objectives for Third Reedy Lake ...... 27 Table 17: Current vs. proposed water regime Ramsar criteria compliance for Third Reedy Lake ...... 33 Table 19: Benefit matrix ...... 34 Table 19: Risk matrix ...... 34 Table 20: Benefit assessment for the objective of restoring Third Reedy Lake to an Intermittent Swampy Woodland ...... 35 Table 21: Risk assessment for the objective of restoring Third Reedy Lake to Intermittent Swampy Woodland ...... 37 Table 22: Modified risk assessment ...... 47
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ACKNOWLEDGEMENTS
Acknowledgement of Country The North Central Catchment Management Authority (North Central CMA) acknowledges Aboriginal Traditional Owners within the region, their rich culture and spiritual connection to Country. The North Central CMA also recognises and acknowledges the contribution and interest of Aboriginal people and organisations in land and natural resource management.
Contributions to the Third Reedy Lake Technical Report The information contained in the Third Reedy Lake Technical Report has been sourced from a variety of reports and field inspections and from individual knowledge and expertise. The North Central CMA acknowledges the assistance of the following people in preparing this document: • Pat Feehan, Ross Plunkett and Anne Graesser, Goulburn-Murray Water (G-MW) • Andrea Keleher and Janet Holmes, Department of Environment and Primary Industries (DEPI) • Scientific Panel Members: o Rhonda Butcher, Water's Edge Consulting o Daniel Stoessel, Arthur Rylah Institute (ARI) o Brett Lane, Brett Lane and Associates o Doug Frood, Pathways Bushland and Environment o Damien Finlayson, URS • Damien Cook, Rakali Ecological Consulting • Anthony Byrne and Gavin Thomas, Biosis • Kerang Lakes Bypass Investigation Project Reference Group • Kerang Lakes Bypass Investigation Community Advisory Group • Expert Review Panel: Terry Hillman and Jane Roberts Louissa Rogers, Emer Campbell, Tim Shanahan and Peter McRostie, North Central CMA
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ABBREVIATIONS AAV Aboriginal Affairs Victoria BE Bulk Entitlement Bonn Convention on the Conservation of Migratory Species of Wild Animals CAMBA China–Australia Migratory Bird Agreement CMA Catchment Management Authority DEPI Department of Environment and Primary Industries EES Environment Effects Statement EPBC Environment Protection and Biodiversity Conservation Act 1999 EVC Ecological Vegetation Class EWP Environmental Watering Plan FFG Flora and Fauna Guarantee Act 1988 FSL Full Supply Level GIS Geographic Information Systems GL Gigalitre (one billion litres) GMID Goulburn Murray Irrigation District G-MW Goulburn–Murray Water JAMBA Japan–Australia Migratory Bird Agreement MNES Matters of National Environmental Significance North Central CMA North Central Catchment Management Authority NVIRP Northern Victoria Irrigation Renewal Project ROKAMBA Republic of Korea–Australia Migratory Bird Agreement TIS Torrumbarry Irrigation System VEAC Victorian Environmental Assessment Council
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GLOSSARY OF TERMS
Episodic Wetland alternates between holding water and being completely dry, with the dry phase being the usual state; flooding occurs rarely and irregularly; surface water
persists for months EVC Ecological Vegetation Class is a vegetation classification system that group s vegetation communities based on floristic, structural and ecological features Full supply The normal maximum operating water level in water storage when not affected by level floods Intermittent Wetland alternates between holding water and being completely dry, but not annually as in seasonal wetlands; surface water persists for months to years Littoral zone Also known as edge zone is characterised by coarser sediments, more habitat structure, and is usually regarded to extend from the surface to the end of the euphotic zone. The euphotic zone is the depth to which light penetrates through the water column and enables photosynthesis – in lakes and deep wetlands this is often restricted to the margins of the wetland. In shallow wetlands it can expand across the whole wetland Semi - Wetland usually holds some water, with annual inflows being equal to or exceeding permanent minimum losses in 90 per cent of years; surface water persists for decades, only drying out in extreme droughts
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1. Goulburn-Murray Water Connections Project The Goulburn-Murray Water (G-MW) Connections Project is a $2 billion works program to upgrade ageing irrigation infrastructure across the Goulburn Murray Irrigation District (GMID) and to save water lost through leakage, seepage, evaporation and system inefficiencies. Works will include lining and automating channels, building pipelines and installing new, modern metering technology.
The GMID uses a number of natural carriers, rivers, lakes and wetlands for both storage and conveyance of water. While the water savings generated are from ‘losses’ within the irrigation system, in some cases the losses from the operating regime provides incidental benefits to environmental assets (SKM, 2008).
Stage 1 of the G-MW Connections Project will implement water distribution and delivery efficiency improvements to deliver an estimated 225 GL/ yr (Long Term Cap Equivalent-LTCE) water savings. This recovered water is returned as additional bulk water entitlement for use by irrigators, the environment and other funders.
Stage 2 of the project is intended to recover an additional estimated 204 GL/ yr (LTCE) of water by 2017- 18. The water recovered from this project is funded by the Commonwealth Government and retained for environmental use (G-MW, 2013a). The Business Case to support Stage 2 provided for a number of ‘Special Projects’ to achieve benefits such as water savings, environmental enhancement and/or improved customer level of service. The Kerang Lakes Bypass Investigation Project (KLBIP) has been identified as a ‘Special Project’ under the NVIRP Stage 2 Business Case (now known as G-MW Connections Project). This project proposes to remove irrigation demand and develop a variable water regime that will enhance the environmental values of the wetlands.
2. Purpose and scope of document The purpose of this Technical Report (Third Reedy) is to document the environmental values, hydrology, modelled wetland watering regimes, potential impact pathways for the alternative water regimes, refinement of the environmental objectives and water regimes and completion of a risk assessment for discussion by the Kerang Lakes Bypass Investigation Project Reference Group (PRG). The recommended environmental water regime documented in this report will be used to assess potential water savings and is an important input to the development of a business case for the Kerang Lakes Bypass. It is intended that this Technical Report is a working document and information presented should be considered in this context. The tasks undertaken to develop the technical report are illustrated in Figure 1. This report has been reviewed by the Project Reference Group, a scientific review panel and the Connections Project Expert Review Panel. The information in this report may be used at a later date to develop an environmental water plan for the wetland.
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Figure 1 : KLBIP development process 3. Background The Kerang Lakes Bypass Investigation Project (KLBIP) will investigate the feasibility of the concept to construct bypass channels around the Reedy Lakes Complex (comprising First, Middle and Third Reedy Lakes), Little Lake Charm and Racecourse Lake (Figure 2). These systems will be referred to as wetlands in this report when not referred to by name. The wetlands are operated as part of the irrigation conveyance system in the Torrumbarry Irrigation Area (TIA). The bypass project investigation has been funded as part of Stage 2 of the Goulburn-Murray Water (G-MW) Connections Project. If the investigation deems that the bypass is feasible G-MW Connections will prepare a Business Case for the Australian Government to secure implementation funding.
The five wetlands are of international and national significance being part of the Kerang Wetlands Ramsar site and are listed in the Directory of Important Wetlands in Australia.
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3.1. Ramsar Convention The Convention on Wetlands of International Importance, otherwise known as the Ramsar Convention, provides the framework for actions on a local, regional and national scale as well as international cooperation, for conservation and wise use of wetlands. Currently there are 168 contracting parties managing over 2,000 Ramsar wetland sites worldwide.
In 1982 the Kerang Wetlands Ramsar site was designated under the Convention of Wetlands of International Importance (Ramsar Convention) as a Wetland of International Importance (Ramsar wetland) (DEWHA, 2008). The site occupies 9,419 ha and is made up of 23 named permanent and temporary wetlands, including permanent freshwater lakes, permanent saline/ brackish/ alkaline lakes, permanent freshwater marshes and seasonal/ intermittent freshwater marshes (Clunie, 2010). Figure 3 illustrates the wetlands that are part of the Kerang Wetlands Ramsar Site.
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Figure 3: Map of the Kerang Wetland Ramsar Site
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To be listed under the Ramsar Convention, wetlands must meet one or more of the internationally accepted criteria. When the Kerang Wetlands Ramsar site was originally designated as Ramsar listed, it satisfied three of the criteria. In 2005 the Ramsar Criteria was updated and the Kerang Wetlands Ramsar site was recognised as satisfying criteria 1, 2, 3, 4, 5 and 6 (Table 1) (Hale, 2009; KBR, 2011). The collective ecological components and processes of the site provide the foundation to its recognised ecosystem values and importance. As well as ecological value, the site is also of significant economic, cultural, spiritual and recreational value. Refer to Landscape Scale Consideration Report (North Central CMA, 2014) for Ramsar listing justification.
Table 1: Kerang Wetlands Ramsar site satisfied criteria (KBR, 2011) Group A: Sites containing representative, rare or unique wetland types
A wetland should be considered internationally important if it contains a representative, rare, or Criterion 1 unique example of a natural or near-natural wetland type found within the appropriate biogeographic region.
Group B: Sites of international importance for conserving biological diversity
Criteria specific to species and ecological communities:
A wetland should be considered internationally important if it supports vulnerable, endangered, Criterion 2 or critically endangered species or threatened ecological communities.
A wetland should be considered internationally important if it supports populations of plant Criterion 3 and/or animal species important for maintaining the biological diversity of a particular biogeographic region.
A wetland should be considered internationally important if it supports plants and/or animal Criterion 4 species at a critical stage in their life cycles, or provides refuge during adverse conditions.
Criteria specific to waterbirds:
A wetland should be considered internationally important if it regularly supports 20,000 or more Criterion 5 waterbirds.
A wetland should be considered internationally important if it regularly supports 1% of the Criterion 6 individuals in a population of one species or subspecies of waterbird.
As a contracting Party to the Ramsar Convention, Australia has the responsibility of managing sites designated as Wetlands of International Importance. This responsibility includes maintaining the ecological character of the site and informing the Ramsar Secretariat of any changes (DEWHA, 2008).This concerns change to ecological character rather than the change to the criteria for which it was listed (DSE, 2006). The Ramsar Convention has defined “ecological character” and “change in ecological character” as (Ramsar, 2005): • “Ecological character is the combination of the ecosystem components, processes and benefits/services that characterise the wetlands at a given point in time” and
• “…change in ecological character is the human induced adverse alteration of any ecosystem component, process and or ecosystem benefit/service.”
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4. Third Reedy Lake 4.1. Background Third Reedy is a 230 hectare wetland located approximately ten kilometres north-west of Kerang. The wetland is the most northerly site in the Reedy Lakes Complex and has been held artificially full (between full supply level 1 (FSL) of 74.6m AHD and 74.2m AHD) since its inclusion into the Torrumbarry Irrigation System in the 1920s (SKM, 2010).
The bathymetry of Third Reedy Lake shows a maximum depth of 1.36 metres (bed elevation 73.2mAHD) with a slight gradient of 0.4 metres to the littoral zone 2 (at 73.6mAHD) (Figure 4). The wetland bed is relatively flat, with only minor variations in depth (refer to Appendix A for the wetland bathymetry map and the rating table prepared by G-MW, 2011). The wetland currently receives inflow from Middle Reedy to the south and provides water to Little Lake Charm via the Torrumbarry No. 7 channel. The wetland supplies irrigation areas to the north via the Torrumbarry 1/7 channel. Scotts Creek to the west can also engage during flood events. Figure 4 shows the location of Third Reedy, including key features.
Figure 4: Map of Third Reedy Lake including key features
1 Full supply level- The normal maximum operating water level of a water storage when not affected by floods. 2 Littoral zone- the shore of a wetland which usually includes the zone of shallow waters at the edge. Commercial-in-Confidence 7 of 71
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5. Water dependent values 5.1. Listing and significance Legislation relevant to the management of species of Third Reedy Lake falls within one international convention, two international agreements, a national legislation and Victorian legislation and advisory listings are shown in Table 2. A full flora and fauna species list recorded at Third Reedy Lake is shown in Appendix C. Table 2: Relevant legislation, agreements, convention and listings recorded in Third Reedy Lake Legislation, Agreement or Convention Jurisdiction Listed Ramsar Convention International Japan Australia Migratory Birds Agreement (JAMBA) International China Australia Migratory Birds Agreement (CAMBA) International Korea Australia Migratory Birds Agreement (ROKAMBA) International × Convention on the Conservation of Migratory Species of Wild Animals (Bonn Convention) International × Environmental Protection and Biodiversity Conservation Act (EPBC Act) National Flora and Fauna Guarantee Act 1988 (FFG Act) State DSE advisory lists (Victorian Conservation Status) State 5.2. Flora Third Reedy Lake is characterised as a permanent open freshwater lake. The wetland has a high density and abundance of dead River Red Gums ( Eucalyptus camaldulensis ) across the entire shallow open water zone which is devoid of aquatic vegetation. In the 1990s, the open water zone was noted to support an abundance of Robust Water-milfoil ( Myriphyllum papillosum ) and Clove-strip ( Ludwigia peplodies subsp. montevidensis ) (McDonnell et al. 1990). The Ecological Vegetation Class (EVC 3) Tall Marsh (EVC 821) (various combinations i.e. Tall Marsh/Cumbungi (Typha spp.), Tall Marsh/ Giant Rush (Juncus spp.) etc) extends for approximately 50 metres from the edge of the wetland to depths of around 0.3-0.7 metres. The boundary of the wetland is characterised by Intermittent Swampy Woodland (EVC 813), comprising of a Red Gum and Black Box ( Eucalyptus largiflorens ) overstory, with a shrubby understory (predominately Tangled Lignum (Duma florulenta )). Small 10m 2 patches of Aquatic Herbland (EVC 653) (which is characterised by rushes and aquatic herbs) is also present particularly in a small depression on the south- east boundary of the wetland (Rakali, 2013). Permanent inundation of Third Reedy Lake has resulted in an outward shift in the zone once occupied by River Red Gums (i.e. historically the wetland body but now the boundary zone). This has allowed Intermittent Swampy Woodland to occupy a zone that was once supporting Black Box dominated communities (fringing zone) (Rakali, 2013). Table 3 show all the EVCs present at Third Reedy and their conservation status within the Victorian Riverina bioregion. Figure 4 and Figure 6 shows a conceptual cross section of Third Reedy Lake. Table 3: Current EVCs within Third Reed Lake and their bioregional conservation status (Rakali, 2013)
Bioregion EVC No. EVC Bioregional Conservation Status in the Victorian Riverina 1 98 Semi-arid Chenopod Woodland Endangered 103 Riverine Chenopod Woodland Vulnerable 104 Lignum Swamp Vulnerable Victorian Not listed for Victorian Riverina (Vulnerable in Murray Fans 653 Aquatic Herbland Riverina bioregion) 813 Intermittent Swampy Woodland Depleted 821 Tall Marsh Depleted 823 Lignum Swampy Woodland Vulnerable 1EVC Bioregional Conservation Status updated using revised wetland BCS spreadsheet supplied by DEPI (compiled by D. Frood)
3 EVC- Ecological Vegetation Class is a vegetation classification system that groups vegetation communities based on floristic, structural, and ecological features. Commercial-in-Confidence 8 of 71
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Figure 5: A conceptual cross section of Third Reedy Lake showing current conditions. Insert map shows cross section position (image not to scale).
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Figure 6: A conceptual model of the littoral zone of Third Reedy Lake as marked in Figure 5 (red) under current regime.
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DSE pre-1750s mapping predicts that the wetland would have historically been a deep freshwater marsh made up of Lignum Swampy Woodland (EVC 823) with fringing zones of Riverine Chenopod Woodland (EVC 103) and Semi-arid Chenopod Woodland (EVC 98). Lignum, the dominant understory species in Lignum Swampy Woodland, can tolerate a flooding duration of three to seven months at a depth less than one metre. With the maximum depth of the wetland being 1.36 metres at full supply level (FSL); it is likely that in reality the wetland may have flooded too frequently and for too long to support Lignum Swampy Woodland. A recent survey identified the EVC Intermittent Swampy Woodland (EVC 813) to be the most likely historical EVC. This is supported by the presence of a large number of dead River Red Gum trees throughout the base of the wetland, at a density uncharacteristic of Lignum Swampy Woodland (Rakali, 2013). Of the 67 native flora species recorded (see Appendix B) at Third Reedy Lake, seven are listed as significant (DEPI, 2013 Ho et al. 2006; SKM, 2010; Rakali, 2013). Four of these are considered water dependent- Branching Groundsel ( Senecio cunninghamii var. cunninghamii ), Short Water-starwort ( Callitriche brachycarpa ), Spiny Lignum ( Muehlenbeckia horrida subsp. Horrid ) and Twin-leaf Bedstraw ( Asperula gemella ). The Short Water-starwort ( Callitriche brachycarpa ) which is located within Intermittent Swampy Woodland EVC is the only species listed under the Flora and Fauna Guarantee Act 1988 (FFG). There are no listed Environmental Protection and Biodiversity Conservation Act 1999 (EPBC) flora species recorded at Third Reedy Lake. All water dependent significant species except for Twin-leaf Bedstraw ( Asperula gemella ) were recorded in the recent survey by Rakali Consulting (2013). A total of 45 exotic species have been recorded at Third Reedy Lake with 82% of these located within Intermittent Swamp Woodland EVC. Table 4 summarises the significant species, their water dependency and listings at Third Reedy Lake. Table 4: Significant flora species recorded at Third Reedy Lake Common Name Scientific Name Water Last IUCN EPBC FFG Victorian dependency 1 record Red status status Conservation List status Senecio cunninghamii var. Branching Groundsel W 2013 r cunninghamii Leptochloa fusca subsp. Brown Beetle-grass T U r fusca Sclerolaena muricata var. Dark Roly-poly T 2013 k semiglabra Atriplex lindleyi subsp. Flat-top Saltbush T 2013 k lindleyi Short Water- Callitriche brachycarpa A 2013 L v starwort Muehlenbeckia horrida Spiny Lignum W 2013 r subsp. horrida Twin-leaf Bedstraw Asperula gemella T / W 1996 r Conservation Status: • Water dependency: T- River terrestrial, A- River aquatic, W- wetland dependent • IUCN: EX- Extinct, EW- extinct in the wild, CR- critically endangered, EN- endangered, VU- vulnerable, NT- near threatened, LC- least concern, DD- data deficient • EPBC: VU – Vulnerable, EN- Endangered • FFG status: L – Listed as threatened • DSE status: e - Endangered, v- Vulnerable, r - Rare, n- Near Threatened, k- Poorly Known, d- Data Deficient • U- unknown year of record 1Water Dependency advised by Significant wetland-dependent flora species spreadsheet supplied by DEPI (compiled by D. Frood) and VEAC, 2008.
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5.3. Fauna Third Reedy Lake represents reasonable habitat for a range of fauna species due to its extensive fringing aquatic vegetation, abundant snags which provide good perching, basking and roosting locations and permanent open water for fish. Seventy-three bird species, two native turtles, three native frogs and eleven native fish species have been recorded at the wetland (Ho et al. 2006; SKM, 2010; Rakali, 2013; Biosis, 2013; DEPI, 2013; BirdLife Australia, 2013). A number of these species are listed as significant, including nine waterbirds and five fish species as well as two turtles. A total of 32 waterbird species are identified as water dependent at Third Reedy Lake, approximately 44% of which can be categorised as fish- eating, 15% as shoreline foragers and 12% as deep-water foragers and 12% as waders. Of particular importance at Third Reedy Lake is the presence of White-bellied Sea Eagle ( Haliaeetus leucogaster ), Caspian Tern ( Anas caspia) and Eastern Great Egret ( Climacteris picumnus victoriae ) which are listed under international migratory bird agreements. Please note that all species listed in Appendix C of the family Anatidae (ducks) are also considered migratory under EPBC Act as per the Convention of International Trade in Endangered Species (CITES) of wild flora and fauna.
In recent surveys by Biosis (2013) and Rakali Consulting (2013) White-bellied Sea Eagle, Eastern Great Egret, Brown Treecreeper (Climacteris picumnus) , Nankeen Night Heron (Nycticorax caledonicus) , Pied Cormorant (Phalacrocorax varius ) and Royal Spoonbill (Platalea regia ) were recorded. Records indicate that the northern section of the wetland has supported small rookeries of Australian White Ibis (Threskiornis molucca ) and Straw-necked Ibis ( Threskiornis spinicollis ) in the past with two colonial nesting events recorded by Ho et al. (2006). SKM (2010) and DSE (2010) identified a total of eight waterbird breeding events at Third Reedy Lake; including Black Swan ( Cygnus atratus ) and White-bellied Sea Eagle (Haliaeetus leucogaster ); however these breeding events were not referenced in those reports and a subsequent search of the literature failed to confirm two of the eight events recorded (DEPI, 2013; BirdLife Australia, 2013). Table 5 summarises the recorded bird breeding events at Third Reedy Lake.
Table 5: Bird breeding events at Third Reedy Lake since 1988 Common Name Scientific Name Year Australian White Ibis Threskiornis molucca 2005, 2006 Straw-necked Ibis Threskiornis spinicollis 2005, 2006 Black Swan Cygnus atratus 1988 White-bellied Sea Eagle Haliaeetus leucogaster 1998 Source: Ho et al. 2006; Clunie, 2010; BirdLife Australia, 2013; DEPI, 2013.
Five significant fish species have been recorded at Third Reedy Lake, five of which are FFG listed. The populations of two species, the EPBC listed Murray Cod (Maccullochella peelii) and Golden Perch (Macquaria ambigua ) are potentially the result of recreational fish stocking at First Reedy Lake. For Golden Perch, the E nvironmental Effects Act 1978 will only be triggered if the population is natural occurring. A study at First Reedy Lake by Hunt et al. (2010) revealed that stocked Golden Perch contributes to 47% of the population. It is therefore inconclusive as to the nativeness of the population in Third Reedy Lake. A second EPBC listed fish species, Murray Hardyhead ( Craterocephalus fluviatilis ), has not been recorded in the wetland, but has recently been identified to inhabit neighbouring Middle Reedy Lake (Biosis, 2013). Two additional significant species have been identified at Third Reedy Lake, the endangered Freshwater Catfish ( Tandanus tandanus ) and the vulnerable Silver Perch ( Bidyanus bidyanus ). Both of these species have not been recorded since 1981; however anecdotal evidence suggests that the dead timber in Third Reedy Lake makes it an exceptional Silver Perch recreational fishing spot. The most abundant fish species
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Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake recorded in the recent survey by Biosis (2013) was the exotic Common Carp ( Cyprinus carpio ) (37% of catch abundance and 99% of the biomass), followed by the native Carp Gudgeon ( Hypseleotris compressa ) (30% of catch abundance and 0.02% of biomass). Other native fish species recorded at Third Reedy Lake include Australian Smelt ( Retropinna semoni ) and Flathead Gudgeon ( Philypnodon grandiceps ) (refer to Appendix C). Two significant turtle species, the Murray River Turtle ( Emydura macquarii ) and Common Long-necked Turtle ( Chelodina longicollis ); have also been recorded at Third Reedy. Although Murray River Turtle was recorded in high numbers in 2006 (total of 19 individuals), no individuals were caught during the Biosis (2013). Further to this only one Common Long-necked Turtle was surveyed compared to three by Ho et al. (2006).
A total of 14 families of macroinvertebrates were also recorded at Third Reedy Lake in the recent Biosis (2013) survey compared to 15 in 2006. Compared to the 2006 survey, the macroinvertebrate taxa recorded are substantially different, with a lack of aquatic molluscs ( Planorbidae and Physidae ) and some dipteral larvae ( Ceratoponidae and Sciomyzidae ) in the 2013 surrey. The substantial change in assemblage may be attributed to non-ideal weather conditions for macroinvertebrates during the survey conducted in February-March 2013. A full list of macroinvertebrates families recorded at Third Reedy Lake can be found in Appendix C. Table 6 lists the significant species recorded at Third Reedy Lake. Table 6: Significant fauna species recorded at Third Reedy Lake Common Name Scientific Name Water Last Inter- IUCN EPBC FFG Victorian depend- record national Red status status Conservation ency 1 treaty List Status Birds Brown Treecreeper Climacteris picumnus Y 2013 LC NT Caspian Tern Sterna caspia Y 1998 J/C LC M L NT Eastern Great Egret Ardea modesta Y 2013 J/C M L VU Hardhead Aythya australis Y 2006 LC VU Musk Duck Biziura lobata Y 2006 V Nycticorax Nankeen Night Heron Y 2013 NT caledonicus Pied Cormorant Phalacrocorax varius Y 2013 LC NT Royal Spoonbill Platalea regia Y 2013 LC NT White-bellied Sea- Haliaeetus Y 2013 C LC M L VU Eagle leucogaster Fish Freshwater Catfish Tandanus tandanus Y 1981 L EN Silver Perch Bidyanus bidyanus Y 1981 VU L VU Craterocephalus Unspecked stercusmuscarum Y 2013 L Hardyhead 2 fulvus Golden Perch Macquaria ambigua Y 2013 NT Murray Cod Maccullochella peelii Y 2006 CE VU L VU Reptiles Murray River Turtle Emydura macquarii Y 2006 VU Common Long- Chelodina longicollis Y 2013 DD necked Turtle Significant fauna key: • Water dependency: Y- water dependent, N- not water dependent • International Treaty: J-JAMBA, C- CAMBA, R-ROKAMBA, B-BONN • IUCN: EX- Extinct, EW- extinct in the wild, CR- critically endangered, EN- endangered, VU- vulnerable, NT- near threatened, LC- least concern, DD- data deficient • EPBC status: VU – Vulnerable, M- Migratory • FFG status: L – Listed as threatened Commercial-in-Confidence 13 of 71
Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
Common Name Scientific Name Water Last Inter- IUCN EPBC FFG Victorian depend- record national Red status status Conservation ency 1 treaty List Status • DSE status: EN- Endangered, CR- Critically Endangered, VU- Vulnerable, NT– Near Threatened, K- Poorly known, DD- data deficient • U- unknown record 1Water Dependency advised by Significant Wetland Dependent Fauna Species spreadsheet supplied by DEPI (compiled by R. Loyn (birds), N. Clements (Reptiles), M. Scrogie (Frogs), P. Papas (Invertebrates), L. Lumsden (Mammals) and J. Kohen and T. Raadik (Fish)). 2Unspecked Hardyhead was not included in the April 2013 release of the Advisory List of Threatened Vertebrate Fauna in Victoria (DSE, 2013). The species has been reassessed as abundant across many locations within Victoria, however it is currently gazetted under FFG (October 2012) and management options that impact this species may trigger the Environmental Effects Act 1978 . 5.4. Representativeness and distinctiveness Third Reedy Lake is currently classified as permanent open water (Lugg et al ., 1989) using the Victorian wetland classification system (Corrick and Norman, 1980). In the North Central CMA region the area of this wetland type has almost doubled in size since European occupation and this wetland type is now considered over represented in the landscape (North Central CMA, 2005). In the Kerang Wetlands Ramsar site, eight wetlands are currently classified as permanent open water. Due to their close proximity and connectivity, as a complex these wetlands are considered significant in the context of the Murray-Darling Drainage Division and nationally (R. Butcher (Water’s Edge Consulting) pers comm., 18 September 2013).
The original pre-European extent of deep freshwater marsh is considered the most depleted wetland category in Victoria and it is estimated that there has been approximately 70% decrease in area since European settlement (DSE, 2010). Table 7 illustrates the area and proportion of permanent open water across various defined landscapes and highlight the relative minor contribution of Third Reedy Lake to the whole Kerang Wetland Ramsar site and the North Central CMA region. Table 7: Current area of Permanent Open water across the landscape North Central region Kerang Wetlands Ramsar site Goulburn-Murray (9,938 ha) Irrigation District (GMID) Permanent Open Water (ha) 28,360 3,840 48,330 Third Reedy Lake (230 ha) 0.78% 5.76% 0.46% 5.5. Third Reedy Lake in the Ramsar context As discussed in Section 3.1 the Kerang Wetlands Ramsar site satisfies Ramsar Criteria 1, 2, 3, 4, 5 and 6. This pertains to the complex being representative of rare and/or unique wetland types, supporting vulnerable, endangered, critically endangered species or threatened ecological communities, supporting plant and animal species important for maintaining biological diversity in the biogeographic region as well as plant and or animal species at critical life stages, drought refuge and high waterbird numbers (DEWHA, 2008). Table 8 compares Third Reedy Lake against the Kerang Ramsar Site in terms of the Ramsar Criteria it meets. As discussed in Section 5.4 the wetland type permanent open water has increased significantly since European occupation and on its own is not considered a rare or unique wetland type (DSE, 2010). However in the Kerang Wetlands Ramsar site this wetland type exists as a collective complex and is considered significant both at the Murray-Darling Drainage Division and national scale. As per Criterion 2, Third Reedy Lake supports a number of vulnerable, endangered and/or critically endangered species with two EPBC listed and three significant IUCN listed water dependent species (Refer to Section 5.3). Further to this Third Reedy Lake also fulfils the requirements of Criterion 3, contributing to
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Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake the freshwater components of the overall biodiversity values of the Kerang Wetlands Ramsar site, particularly fish, reptiles, frogs, flora and waterbirds. Criterion 4 relates to the wetland supporting critical life stages of wetland dependent species. At the Kerang Wetland Ramsar site and Third Reedy Lake this refers predominantly to supporting migratory waterbirds. Third Reedy Lake supports three migratory species listed under international treaties (Section 5.3). Further to this Third Reedy Lake is considered an important drought refuge for waterbirds and fish, being both a permanent freshwater wetland and being in close proximity to the Loddon River. Criterion 5 relates to supporting high numbers of waterbirds. Although it is unlikely that Third Reedy Lake on its own can support enough waterbirds to meet Criterion 5, its habitat contributes significant to this criterion met by the Kerang Wetlands Ramsar Site as a whole. Criterion 6 is unlikely to be fulfilled at just Third Reedy Lake as the site as a whole supports with the wetland being part of the Reedy Lakes that supports 10% of the regional breeding population of Straw-necked Ibis and Australia White Ibis and more than 5% of the Victorian breeding population of Royal Spoonbill (Clunie, 2010). Table 8: Third Reedy Lake against Ramsar Criteria Kerang Third Reedy Summarised criteria Ramsar site Lake 1. Containing representative, rare or unique wetland types o 2. Support vulnerable, endangered, or critically endangered species or threatened ecological communities 3. Support populations of plant and/or animal species important for maintaining the biological diversity of a particular biogeographic region. 4. Support populations of plant and/or animal species important for maintaining the biological diversity of a particular biogeographic region. 5. Regularly supports 20,000 or more waterbirds. o 6. Regularly support 1% of the individuals in a population of one species or subspecies of × waterbird. KEY: • - criterion fulfilled by site/ wetland • × - criterion not fulfilled site/ wetland • o - site makes a contribution to fulfilling the criterion as a whole 6. Hydrology Wetland hydrology is the most important determinant in the establishment and maintenance of wetland types and processes. It affects the chemical and physical aspects of a wetland, which in turn affects the type of values the wetland supports (DSE, 2005a). A wetland’s hydrology is determined by surface and groundwater inflows and outflows, in addition to precipitation and evapotranspiration (Mitsch & Gosselink, 2000 in DSE, 2005a). Duration, frequency and seasonality (timing) are the main components of the hydrologic regime for wetlands and rivers. 6.1. Natural regime Under natural conditions Third Reedy Lake would have been an intermittent wetland receiving water irregularly during flood events in the cooler winter months of wet years. Originating from the Loddon River, the water would have entered Washpen Creek before discharging into First Reedy Lake. Once First Reedy Lake was full water would travel to Middle Reedy Lake then onto Third Reedy Lake. The nature of water movement within the Reedy Lakes Complex would have meant that Third Reedy Lake flooded less frequently and experience more prolonged drying phasing compared to its neighbouring counterparts Commercial-in-Confidence 15 of 71
Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
(SKM 2008). During high flow events, Third Reedy Lake could also receive water via Sheepwash Creek to the east and would convey water to Little Lake Charm via Scotts Creek at the western boundary (SKM 2010). 6.2. Historic/current water management The management of the Third Reedy Lake for irrigation has altered its natural watering regime. Third Reedy Lake is currently maintained as a permanent wetland through its inclusion in the Torrumbarry Irrigation system. The wetland has remained inundated since the 1920s through good quality fresh water inflows from First and Middle Reedy lakes that maintain depth at a maximum of 74.56m AHD and a minimum of 74.2m AHD (North Central CMA, 2012; SKM, 2010). Table 10 shows a range of water level percentiles based on data from June 1986 and July 2013 for Third Reedy Lake. The data shows that the wetland actually operates above 74.47 m AHD for 95% of the time, with a level of 74.56m AHD for 50% of the time.
Table 9: Third Reedy Lake water level percentiles (June 1986 to July 2013) Percentile 5% 10% 25% 50% 75% 90% 95% Water level (m AHD) 74.47 74.49 74.52 74.55 74.56 74.58 74.6 Source: R. Stanton (G-MW), 2013
The wetland is constantly kept at full supply level between 1 August and 31 January. After 31 January, Third Reedy Lake is drawn down for irrigation purposes by up to 30 cm. At the end of the irrigation season the wetland can be further drawn down by evaporation. The outflow released from Third Reedy Lake to Channel No. 7 is determined by downstream demands and the volume required to meet the targets of the downstream storages. Channel No. 7 flows through Little Lake Charm and then onto Racecourse Lake and Lake Kangaroo (SKM, 2010). The watering cycle over the last nine years is shown in Table 10. Table 10: Third Reedy Lake wetting/drying calendar Year 2004-05 2005-06 2006-07 2007-08 2008-09 2009-10 2010-11 2011-12 2012-13 Status W W W W W W W W W
KEY: W- wet ; D- dry
6.3. Trajectory for the environmental values of Third Reedy Lake under current water regime Third Reedy Lake was assessed by Lugg et al. (1989) as having an overarching moderate conservation value mainly for conservation of native flora and reptiles. Important habitat features include sections of Tall Marsh, Giant Rush, Lignum and dead River Red Gums that provide both standing and woody debris. However it is noted that aquatic vegetation is severely depleted and negligible in the open water zones of Third Reedy Lake and this may account for the reduction in Murray River Turtle records between 2013 (Biosis, 2013) and the abundant surveys in 2006 (Ho et al. 2006) and 1989 (Lugg et al. 1989). In addition, the habitat value of the dead River Red Gums (particularly roosting and nesting) will eventually be lost under a permanent regime, as timber will decay (process occurs when inundated for over ninety years) and new trees will be unable to establish. Lugg et al. (1989) proposed that Third Reedy Lake be removed from the irrigation system and managed as a semi-permanent wetland to maximise the conservation values (Table 16). This included facilitating seasonal variation and allowing an occasional drying phase. The ecological response to changing the wetland hydrology is unknown. Rakali (2013) concluded that the biodiversity and ecological condition in all of the KLBIP wetlands has declined significantly since European settlement. However, despite these changes biodiversity is still considered relatively high with much of
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Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake the vegetation having developed in response to environmental change. It is therefore likely that the current ecological state of the KLBIP wetlands will remain the same if permanent water are maintained. These conditions have effectively locked the wetlands into being stable environments and subsequently a promotion in diversity over time will not occur (Jane Roberts, pers comm. , November 2013). However future changes to the hydrological regime at Third Reedy Lake will have the potential to introduce both positive and negative ecological consequences as discussed in Section 7.
6.4. Alternative Water Regime Scenarios for Third Reedy Lake Drawing on previous work by SKM (2010) and KBR (2011), the North Central CMA (2012) developed alternative wetland watering regime scenarios for all of the five KLBIP wetlands. The process for developing alternative wetland water regime scenarios has been informed by consideration of watering requirements for environmental values, wetland water regime definitions. During the process weighting of values and consideration of where water requirements were conflicted did not occur. The proposed water regimes that were identified and modelled for Third Reedy Lake are presented in Table 11. Table 11: Third Reedy Lake proposed watering regime scenarios (North Central CMA, 2012) Wetland type 1 Regime Frequency of wetting : 1 in 4 years Timing: Winter/Spring Dry- episodic Depth: FSL 74.56 mAHD Duration: up to 10 months (allow to dry naturally) Frequency of wetting : 2 in 3 years Timing: Winter/Spring filling Depth: Deep Freshwater Marsh- Year 1 - 74.56 mAHD intermittent Year 2 - 74.2 mAHD Year 3 - no fill Duration: 7-10 months Frequency of wetting: annually Open Freshwater Lake- Timing: Fill Winter/Spring semi-permanent Depth: FSL – 74.56 mAHD Duration: 12 months – allow to evaporate by 1m (to 73.74mAHD) at least two years in a row
Open Freshwater Lake- No change permanent
1Wetland types are based on Brock et al. 2003: • Episodic- Wetland alternates between holding water and being completely dry, with the dry phase being the usual state; flooding occurs rarely and irregularly; surface water persists for months • Intermittent- Wetland alternates between holding water and being completely dry, but not annually as in seasonal wetlands; surface water persists for months to years • Semi- permanent- Wetland usually holds some water, with annual inflows being equal to or exceeding minimum losses in 90 per cent of years; surface water persists for decades, only drying out in extreme droughts
Hydrological modelling for each watering regime scenario was undertaken to estimate long term losses so that the water savings potential of the bypass intervention could be estimated. The modelling also predicted the long-term daily water level regimes under a range of possible operational regimes so that wetland potential for ecological rehabilitation can be evaluated, and the regimes refined accordingly (Gippel, 2012). A summary of the results is provided in Table 12 and shown in Figure 7 . Table 12: Third Reedy Lake modelling results (Gippel, 2012) Watering regime scenario Hydrological model setting Period wetland is dry Dry- episodic 1 in 4 years to 74.56 m AHD Two years Commercial-in-Confidence 17 of 71
Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
2 in 3 years, Year 1 to 74.85 m AHD; Year 2 to Deep Freshwater Marsh- intermittent Six months 74.2 m AHD Open Freshwater Lake- semi- Littoral zone dry, small 10 in 10 years to 74.56 m AHD permanent fluctuation Open Freshwater Lake- permanent Not applicable Never
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Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
Dry- episodic
Deep Freshwater Marsh- intermittent
Open Freshwater Lake- semi-permanent
Open Freshwater Lake- permanent
Figure 7: Predicted water levels under each proposed regime (Gippel, 2013)
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Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
6.5. Additional Analysis of Alternative Water Scenarios for Third Reedy Lake Consultation with GMW and the Connection Program Expert Review Panel (ERP) led to additional alternative scenarios being tested in 2014. Hydrological modelling for each watering scenario was undertaken to estimate the long term losses and potential water savings. A preferred scenario was selected in conjunction with GMW and the ERP from this analysis and used in the remaining report. The preferred scenario provides a 1 in 4 water regime with filling to 74.00m AHD and 74.56m AHD as presented in Figure 8.
Figure 8: Predicted water levels and percentage of bed dry under updated and preferred regime (Gippel, 2014)
6.6. Groundwater assessment URS (2013) undertook a hydrogeological salinity risk analysis for the KLBIP using groundwater modelling based on a Monte Carlo simulation technique. This analysis considered the salinity risk of four alternative water regimes as described in Section 6.4 and Table 11. Six bores located around and within one kilometre of Third Reedy Lake were selected to assess the groundwater levels and potential for surrounding groundwater to be discharged into the wetland if its levels were reduced. Average salinity levels for Third Reedy Lake typically range from 200 to 1,300 EC (G-MW, 2010). The data periods for the assessment are limited, with some bores having short and sporadic monitoring periods. For example bore 58554 has a data period of 1988 to 2012 with a total of 105 data points. The findings of the hydrogeological data review are summarised in Table 13 below.
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Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
Table 13: Third Reedy Groundwater Risk Assessment (URS, 2013) Watering regime Hydrogeological Risk Assessment Salt risk rating 4 scenario
Has the greatest salinity risk with 80th percentile 5. The salinity of Third Reedy Lake is estimated to increase by 3,103 EC upon refilling. The 90 th percentile Moderate to Dry- episodic salinities are estimated to be above 10,000 EC upon refilling indicating a High higher salinity risks. The episodic watering scenario has a higher probability of significantly more salt in the wetland.
Relatively low salinity risk with 80th percentile. The salinity of Third Reedy Deep Freshwater Marsh- Lake is estimated to increase by less than 309 EC upon refilling. The 90 th Low intermittent percentile salinities are estimated to increase by approximately 1,900 EC upon refilling indicating low salinity risks.
Open Freshwater Lake- Relatively low salinity risk with 80th percentile. Third Reedy Lake salinities of Low semi-permanent less than 547 EC increase upon refilling.
Current operating levels are generally above the surrounding groundwater Permanent Open levels for much of the time, therefore acting as barriers to brackish Low Freshwater Lake groundwater flow.
The episodic watering scenario presents the greatest risk for saline groundwater discharge into Third Reedy Lake. URS (2013) concluded that it is possible that surrounding groundwater could be discharged into Third Lake if its wetland levels were reduced. There are potential salinity risks when surrounding saline groundwater is higher than the wetland level creating a hydraulic gradient towards the wetland. A review of the groundwater hydrograph (Figure 9) near Third Reedy Lake indicates relatively high groundwater levels from 1988 through to 2000 and relatively low groundwater levels from 2000 through to 2012 reflecting the broader climatic conditions and changed irrigation practices.
4 Risk rating based on salt tolerances for wetlands: Very Fresh = up to 1500 EC, Fresh = 1,500 to 4,500, slightly saline = 4,500 to 15,000, Saline = 15,000 to 52,000 (Roberts and Marston, 2011).
5Percentile: indicates the value below which a given percentage of observations in a group of observations fall. For example, 80th percentile is the value below which 80 percent of the observations may be found. Commercial-in-Confidence 21 of 71
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Figure 9: Bore Hydrograph: Nested Site 58533/58554 URS (2013) have suggested that salinity risk can be reduced in all cases by: • reducing the duration when wetland levels are low (or absent) especially times when surrounding groundwater levels are elevated (following sustained years of average or above, rainfall)
• reducing the depth to which wetland levels are reduced between filling phases. 6.7. Additional Groundwater Assessment Additional hydrogeological salinity risk analysis for the KLBIP using groundwater modelling based on a Monte Carlo simulation technique was undertaken by URS in 2014 (URS 2014). The hydrogeological salinity risk analysis was run for the period 1891 to 2010. The updated hydrogeological risk analysis has assumed the wetland level and groundwater input frequency curves are directly correlated and that groundwater levels are inversely correlated with the interval between wetland filling to full supply level when flushing can occur (Refer to URS 2014 pg3). The results from the hydrogeological salinity analysis indicated that the updated preferred water regime has a moderate to high salinity risk (Refer to Table 14).
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Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
Table 14: Updated Third Reedy Groundwater Risk Assessment (URS, 2014) Watering regime Hydrogeological Risk Assessment Salt risk rating 6 scenario The 80th percentile salinity of Third Reedy Lake is estimated to be 3,360 EC upon refilling. The 90 th percentile salinities are estimated to be above 8,000 Moderate to Updated Preferred EC upon refilling indicating a higher salinity risks. The 50 th percentile salinities High (without Scenario are estimated to be 500EC upon refilling. The updated watering scenario has mitigation) a higher probability of significantly more salt in the wetland. The salinity risks associated with the updated preferred regime pose risks in meeting ecological objectives and will require further investigation to better quantify the risk and to determine appropriate mitigation options such as watering the wetland and possibly changing the operation of the Kerang lakes system. 7. Rationale for recommended water regime The risks and benefits associated with each of the wetland watering regime scenarios developed for Third Reedy Lake have been assessed with regards to the wetland’s Ramsar criteria, threatened species, EVCs, Salinity and Acid Sulfate Soils (ASS). The below section outlines the findings of the assessment with Table 15 summarising whether each watering regime provides a benefit, impact, no change or if additional investigations are required. Section 7 assists in refining the recommended water regime and is used to support the more detailed objective setting and water regime recommendations outlined in Section 8. Ramsar Criteria As identified in Section 3.1 the Kerang Wetlands Ramsar site satisfies the criteria associated with being a representative, rare or unique example of a wetland type (Criterion 1). Third Reedy Lake is currently described as a Permanent Open Freshwater wetland however its original (pre-1750s) classification was determined to be Deep Freshwater Marsh. As identified in Section 6.1, the position of Third Reedy Lake in the landscape suggests that the wetland flooded less frequently and experienced more prolonged drying phases compared to the other Reedy Lakes, which is also evidenced by the number of dead trees scattered throughout the wetland. Due to the long history of permanent inundation at Third Reedy Lake, the majority of negative changes are likely to have already occurred and the wetland is now in a state of equilibrium. It is therefore anticipated that ongoing permanent management would not result in any additional loss to these values, with the exception of stands of dead trees which will eventually be lost through rotting. This rotting would however have significant impact on habitat available for aquatic fauna and roosting and nesting for waterbirds (Criteria 5 and 6) (Rakali, 2013 and Biosis, 2013). Therefore maintaining a permanent or near permanent regime will eventually reduce habitat, potentially leading to less habitat diversity in the longer term.
Birds Species
6 Risk rating based on salt tolerances for wetlands: Very Fresh = up to 1500 EC, Fresh = 1,500 to 4,500, slightly saline = 4,500 to 15,000, Saline = 15,000 to 52,000 (Roberts and Marston, 2011). Commercial-in-Confidence 23 of 71
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The Kerang Wetlands Ramsar site supports a high diversity and abundance of waterbird species with 37 species listed under international bilateral agreements and 28 waterbird species recorded as breeding at the wetlands since 1980 (KBR, 2011). Thirty two waterbird species (Section 5.3), including the White- bellied Sea Eagle, Caspian Tern and Eastern Great Egret have been recorded at Third Reedy Lake as well as small rookeries of Australian White Ibis and Straw-necked Ibis. As mentioned above, the dead trees within the wetland provide habitat for waterbirds (hollows and roosting perches), however under the current watering regime this will eventually be lost. Improved habitat for bird roosting, feeding and breeding is best achieved through provision of a natural wetting / drying water regime to encourage regeneration of River Red Gums and Intermittent Swampy Woodland understory. Kingsford and Porter (2006) found that waterbird density was ten times higher and diversity was twice as high in unregulated wetlands than wetlands that were artificially kept permanent. Fish Species The recent fish survey of Third Reedy Lake indicated a significant increase in Common Carp numbers when comparing the 2013 and 2006 surveys (Biosis, 2013; Ho et al. 2006). The survey concluded that Common Carp made up 99% of the biomass placing increased pressure on both native fish and vegetation communities (Biosis, 2013). Maintaining a permanent system is providing Common Carp with appropriate conditions to thrive and out-compete natives for resources. It is commonly accepted that one of the most effective control mechanisms for Common Carp is full drying of the wetland. This will also allow a more diverse and productivity habitat for native fish when the wetland is re-filled (providing connectivity with other wetlands is maintained). Frogs / Turtles Species Barking Marsh Frog ( Limnodynases fletcheri), Peron’s Tree Frog ( Litoria peroni ) and Spotted Marsh Frog (Limnodynastes tasmaniensis) were recorded at Third Reedy Lake in 2013 (Biosis, 2013). However records indicate that there has potentially been a decline in Common Long-necked Turtle and Murray River Turtle populations in the last 30 years (Biosis, 2013). Murray River Turtle, which is listed as vulnerable in Victoria tends to favour permanent watering regimes however there is the potential for the species to move. However, Common Long-necked Turtles, which are also listed with a Victorian conservation status, prefer ephemeral backwaters (Howard et al. 2013). Additional investigations would be required to assess the status of turtle and frogs at Third Reedy Lake and how a changed regime may impact on these populations in the future. EVCs/Flora The narrow distribution and extent of the littoral and aquatic EVCs (i.e. Tall Marsh, Intermittent Swampy Woodland and Lignum Swamp) as well as the abundance of dead River Red Gums at Third Reedy Lake is the direct result of the wetlands permanent regime. Maintaining this regime is unlikely to cause further degradation to the already established vegetation communities; however it will result in the eventual loss of dead timber through rotting. If the wetland was allowed to periodically dry and suitable variation in the water level was achieved, regeneration of River Red Gums from seed would be facilitated. The removal of stable, high water levels would also assist in the control of environmental weeds (e.g. Willows) (and exotic fish species (e.g. Common Carp) as discussed above) and benefit the only FFG listed flora species which inhabits the Intermittent Swampy Woodland zone of the wetland. Salinity / Acid Sulfate Soils Commercial-in-Confidence 24 of 71
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The hydrogeology study has indicated that there are some salinity and Acid Sulfate Soils (ASS) risks associated with instigating a drying regime, with the greatest risks ranging from the episodic through to the lowest risk of no change. If ASS are present, partial drying to complete drying of the wetland bed will expose sediments which may either contain sulfuric acid (sulfuric material), or have the potential to form sulfuric acid (sulfidic material), or cause de-oxygenation (monosulfidic material), or release contaminants when the sulfide materials are exposed to air (MDBA, 2010). This can potentially impact on the aquatic environment (flora and fauna values), water supply, infrastructure and public health. Additional investigations are required to assess the impact of drying out Third Reedy Lake, including pH soil analysis as the wetland is dried. The study also indicates that regional groundwater levels need to be taken into account when managing the water regime management of Third Reedy Lake to minimise the risk of saline groundwater intrusion (URS, 2013) as discussed in Section 6.5. Overall summary Third Reedy Lake is considered a high value wetland with reasonably diverse flora and fauna community. Although likely to have historically maintained water on an intermittent basis, hydrological management of the wetland to meet irrigation requirements has resulted in stable, permanently high water levels. Over 90 years of these conditions has allowed a suite of species to adapt and it is now likely that the majority of these values will be maintained, with the exceptional of standing timber, if management of the wetland remains the same in the future. There is however potential to significantly improve Third Reedy Lake through implementing periodic drying. Currently the wetlands water regime favours introduced species, particularly Common Carp (Biosis, 2013). A wetting and drying regime would align more closely with the wetlands natural behaviour and promote a more biological diverse assemblage of flora in the open water, littoral and drawdown zones. However additional investigations are required for reptiles, salinity and ASS to ensure that the re- introduction of a drying regime does not impact negatively on the wetlands current environmental values. Table 15 summarises the information supplied in Section 7 by indicating the likely impact of each regime on the key values. Please note that the symbols used do not aim to quantify the degree of changed expected (i.e. low benefit compare to a high benefit), instead are simply used to indicate the predicted nature of the change (i.e. positive or negative). The table indicates that the preferred regime for Third Reedy based on this information, is an episodic to intermittent watering regime (as per Table 15). Section 8 further expands on this information by exploring the management objectives and more clearly defines the preferred water regime for Third Reedy Lake.
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Table 15: Risk assessment associated with each watering regime scenario at Third Reedy Lake Biota Ramsar EVCs / Water regime scenario Frogs / Salinity ASS Criteria Birds Fish flora turtles Dry- episodic / Deep Freshwater Marsh- - intermittent Open Freshwater Lake- semi- - permanent No Change - Permanent Open - - -* - - - - Freshwater Lake KEY: Benefit - No change expected o Additional investigations, management required Negative impact likely TBC Waiting for results from the Socio-economic study (RMCG 2013) *Native fish community placed under increased pressure from significant Carp populations
8. Management objectives As Third Reedy Lake is used for water supply it is currently maintained permanently full. Table 16 outlines the previous management objectives that have been recommended for Third Reedy Lake. Table 16: Previous management considerations Source Objectives Recommendation Manage as a semi- • Water level be allowed to fluctuate as much as possible (i.e. high in permanent wetland winter/spring and low in summer/autumn so that the littoral zone is flooded) Lugg e t primary for the • Wetland filled in winter/spring and allowed to decline by evaporation al. 1989 conservation of native flora • Wetland allowed to dry occasionally (e.g. three to four months every year or and fauna one in three/four years) Improve the condition of the vegetation • Near annual drying SKM, communities, providing • Winter/spring timing with one in two to three years (variable duration up to 10 2010 enhanced habitat for months) waterbirds
KBR, Maintain current ecological 2011 • Maintain at or near fully supply level with annual fluctuations condition of littoral zone (draft)
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8.1. Management goal The overall management goal for Third Reedy Lake is based on the information presented above including consideration for the ecological values (current and future) and the wetland’s historic natural regime.
Third Reedy Lake goal Provide a watering regime that restores Third Reedy Lake to a deep freshwater marsh (dominated by Intermittent Swampy Woodland (EVC 813)) able to support recruitment of River Red Gums ( Eucalyptus camaldulensis ) and promoting a diverse and extensive range of habitat suitable for a variety of waterbirds.
The outer margins of the wetland would be similar to what is currently present (predominately Black Box and some River Red Gums and shrubby understory) however the quality of vegetation will be improved and regeneration encouraged through fluctuations in water level. The Intermittent Swampy Woodland zone would extend throughout the wetland, with the dominant species being River Red Gums. The deeper zones would be more characteristic of a shrubby Intermittent Swampy Woodland with lignum, sedges and cane grass present. During wet phases, Aquatic Herbland (EVC 653) may be present on outer margins. When the wetland dries this EVC may shift to a corresponding dry EVC such as Floodway Pond Herbland (EVC 810).
8.2. Ecological and hydrological objectives Ecological objectives for Third Reedy Lake represent the desired ecological outcome for the wetland and were developed to determine the optimum watering regime for the wetland to protect and promote high ecological values. Table 17 considers the ecological values of Third Reedy Lake (Appendix C) and sets a range of ecological objectives and trajectories based on managing for the goal proposed in Section 8.3. Please note that Table 17 considers the full suite of ecological objectives for First Reedy Lake and accordingly, these objectives will be refined should an Environmental Water Plan be developed.
Table 17: Proposed ecological objectives for Third Reedy Lake
Ecological objective Justification Hydrological requirement
Habitat objectives 1.1 Maintain health of Supports waterbird breeding existing Black Box fringing (nests, hollows, fallen timber etc). Fill to full supply level (74.56 mAHD) in late winter or wetland vegetation Also provides shade to instream early spring. This level will not flood the trees, but will (within Intermittent habitat and a source of seed for provide water to the bank soil profile. Swampy Woodland) recruitment.
1.2 Restore opportunities Promote recruitment opportunities for River Red Gum by Red Gums provide important for recruitment of River inundating once in every 2-4 years for a period of 2-4 waterbird habitat and woody Red Gum trees through months (Robert & Marston, 2011). Ensure period of debris. body of wetland summer-autumn drying (Lloyd et al. 1993 in DSE, 2004).
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Ecological objective Justification Hydrological requirement
Understory Intermittent Swampy 1.3 Restore diverse Woodland assemblage (i.e. Tangled understory Intermittent lignum, salt bush etc) provides Swampy Woodland important duck and waterfowl Lignum generally requires inundation once in every 3-5 vegetation (i.e. lignum habitat, fish species (when years for a period of 3-7 months (Robert & Marston, and sedge communities) inundated), invertebrates, turtles 2011). in the body of the and frogs and a food source for wetland able to withstand aquatic and terrestrial herbivores. fluctuating water levels Also filters water. Species/community objectives Linked to habitat objectives 1.1 and 2.1 Restore waterbird 1.2. Provide a range of habitat breeding opportunities types suitable for waterbird Provide suitable habitat as per habitat objectives nesting, resting and breeding. ensuring slow recession of water level. Generally, the significant species currently at Third Reedy Lake are Linked to habitat objective 1.1, 1.2 stimulated by flooding between September and May and 2.2 Restore waterbird and 1.3 which includes providing require permanent water under nests for 5 to 12 months feeding opportunities terrestrial and aquatic insects/macros and plant matter. 2.3 Provide opportunistic Linked to habitat objective 1.3 and Expose shallower areas to promote diversity of aquatic turtle and frog feeding species objective 2.2. plants for feeding opportunities. and breeding 1. Process objectives Facilitates dispersal of seeds, micro Ensure connectivity remains under modernisation 3.1 Maintain connectivity and macro organisms, fish, frogs Ensure water regimes are managed across all three between Reedy Lakes and turtles. Also maintains water Reedy Lakes to ensure dispersal can take place. quality through exchange of water. A diversity of biological and chemical process takes place during 3.2 Restore ecological drying phase i.e. germination, Some fluctuations in water level at littoral zone (specific process associated with aeration of sediments, increased requirements dependent on species). intermittent drying organic matter input, promotes diverse habitat types (i.e. drawdown zones during drying) etc Source : Barker et al. 1995; Rogers & Ralph, 2011; Roberts & Marston, 2011; DSE, 2012a; DSE, 2012b; Biosis, 2013; Rakali, 2013. 8.3. Proposed water regime Based on the supporting ecological values and subsequent defined ecological and hydrological objectives for Third Reedy Lake, a wetland water regime has been derived and is outlined below. Adaptive management 7 will be integrated into the management of Third Reedy Lake to counter any potential adverse risks. Figure 10 shows a schematic cross section to illustrate the various components of the wetland under the proposed water regime while Appendix A shows expected exposed area.
7 Adaptive management: A systematic process for continually improving management policies and practices by learning from the outcomes of previously employed policies and practices. Commercial-in-Confidence 28 of 71
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Timing: Fresh inflows in late winter early spring Frequency of Minimum: 1 in every 4-5 years 1 wetting: • longer between filling events will be detrimental to River Red Gums Optimum: 1 in every 3-4 years (long term regime) Maximum: 1 in every 2 years • important during River Red Gum establishment phase • understory (i.e. lignum and sedge communities) with fluctuating water levels Duration: Variable depending on habitat however: • Fringing zone- predominately Black Box o 2 to 3 months of inundation (for moderate to good canopy and flowering) • Wetland zone- (River Red Gum overstory and lignum/sedge understory) o 2 to 6 months preferable for Red Gum (for woodland) o saplings require one to two months of follow up inundation • Deeper sections can remain inundated for up to 7 months (sedges/lignum) Extent and depth: • Inundate to 74.56mAHD (1.5 metres) and maintain depth for approximately 1 to 3 months before natural drawdown. • Establishment - provide a low level follow-up fill (approximately 30-50cm depth) for 4-6 weeks • Rate of rise and fall 5cm per day (Tucker et al. 2002). Salinity • Groundwater salinity for River Red Gum should be less than 4,000 EC subject to tree providence (Overton and Jolly 2004, cited in Rogers and Ralph, 2011) Variability: High
An initial establishment watering regime is recommended to promote conditions suitable for Red Gum seedlings. This regime prescribes:
Establishment phase: A filling regime that provides opportunities for River Red Guns to establish across the wetland by allowing for seed release, seed strike and establishment of seedlings. The regime will include filling wetland to between 74.2m-74.56m AHD and allowing wetland to dry by natural drawdown. When appropriate this will be followed by a series of low level fills (approximately 0.3m to 0.5m deep) to encourage establishment of River Red Gums. The establishment phase will require adaptive management depending on the response from River Red Gum recruitment. This regime should be followed for two to three cycles or until desirable number of saplings have established. Once River Red Gum saplings has established the regime should shift to:
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Long term management: Providing a watering regime that returns Third Reedy Lake to a deep freshwater marsh dominated by River Red Gums ( Eucalyptus camaldulensis ) with a sedge and lignum understory and fringing Black Box community. Fill once every four years to 74.00m AHD with every third fill to 74.56m AHD. Maintain at 74.56m AHD for one month duration to maintain Black Box and recruited River Red Gums. For other events fill to 74.00m AHD to maintain recruited River Red gums and support lignum and sedge community and allow natural drawdown with wetland remaining dry for the following three years before filling again. Adaptive management is required to ensure the salinity tolerances of ecological objectives i.e. River Red Gum, are not exceeded.
Achievement of this management goal assumes the risks associated with salinity are mitigated (Refer to Section 10). It should be noted that implementation of the preferred watering regime should occur gradually to ensure sufficient time for the targeted ecological values to respond. An adaptive management program will need to be implemented as part of the Environmental Watering Plan that needs to be developed. Appendix A shows the indicative drawdown zone under the preferred regime.
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Figure 10: A conceptual cross section of Third Reed Lake under proposed regime. Insert map shows cross section position (image not to scale).
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Figure 11: A conceptual model of the littoral zone of Third Reedy Lake as marked in Figure 9 (red) under proposed regime.
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9. Potential Risk, Adverse Impacts and Benefits 9.1. Impact to current Ramsar Criteria The national guidelines for Ramsar wetlands advise that under the convention, Australia is obliged to provide a notification of change for “human-induced adverse alteration” (DEWHA, 2009). This concerns change to ecological character rather than the change to the criteria for which it was listed. The current ecological character description was prepared in 2006 (DSE, 2006). The proposed water regime at Third Reedy Lake will result in a ‘human induced’ change to the ecological character; however this change is likely to be ‘positive’ resulting in an improvement in ecological character through promoting habitat diversity. The changes proposed will shift the wetland from permanent open water wetland to a deep freshwater marsh, which is under represented in both the bioregion and Victoria. It is likely to also facilitate an increase in waterbird use, particularly feeding opportunities during the highly productive drawdown and filing stages. This may make the wetland an important habitat for critical life stages. Furthermore the expansion of Intermittent Swamp Woodland EVC will facilitate an increase in habitat available for waterbird roosting and nesting. Table 18 compares the current regime to the likely outcomes of the optimum regime in terms of compliance with Ramsar criteria. Table 18: Current vs. proposed water regime Ramsar criteria compliance for Third Reedy Lake Current Proposed Summarised criteria regime Regime 1. Containing representative, rare or unique wetland types o 2. Supports vulnerable, endangered, or critically endangered species or threatened ecological communities 3. Support populations of plant and/or animal species important for maintaining the biological diversity of a particular biogeographic region. 4. Support plant and/or animal species at a critical stage in their life cycles, or provides refuge during adverse conditions.
5. Regularly supports 20,000 or more waterbirds. o o 6. Regularly support 1% of the individuals in a population of one species or subspecies of × × waterbird. KEY: • - criterion fulfilled by site/ wetland • ×- criterion not fulfilled by site/ wetland • o- site makes a contribution to fulfilling the criterion as a whole 9.2. Risk and benefit assessment The risk and benefit assessment methodology adopted for this project is based on the US EPA Guidelines for Ecological Risk Assessment (US EPA 1998 in Ecological Associates, 2010) as utilised in Ecological Associates (2010). This methodology uses the same principles and steps as the Australian/New Zealand Standard for Risk Assessment (AS/ NZS ISO 31000). A qualitative benefit and risk assessment has been undertaken to assign the ecological effect of implementing the recommended environmental watering regime. The benefit and risk matrices used to assign the levels of benefit and risk is provided below.
The benefit component has the overall objective of assessing the benefit of the water regime on the ecological objectives developed in Table 17. The relationship between exposure (probability of occurrence) and the ecological effect (ability to meet the ecological objective) provide the basis for evaluating the level of benefit (Table 19). The results for the benefit assessment are presented in Table 21.
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Table 19: Benefit matrix Benefit Matrix Ecological Effect Fails to meet Partially meets Meets Exceeds objectives objectives objectives objectives Low Very low Very low Low Moderate Remote/ weak/ insignificant extent Minor Very low Low Moderate High Rare/ mild/ localised Moderate Low Moderate High Very high Exposure Exposure Common/ strong/ broad Strong Moderate High Very high Very high Frequent/ intense/ extensive
Benefit Description Very low There is little to no benefit to the ecological objective. Low Low benefit to the ecological objective. Moderate There is a reasonable benefit to the ecological objective. High There is a considerable benefit to the ecological objective. Very High The benefit on the ecological objective is considered very high.
The risk component aims to assess the ecological risk associated with the proposed water regime and considers a range of endpoints that describe and represent all the significant ways that the ecological objective might be enhanced or degraded by the water regime. The relationship between exposure (probability of occurrence) and the ecological effect (severity of the impact) provide the basis for evaluating the level of risk (Table 20). The results for the risk assessment are presented in Table 22.
Table 20: Risk matrix Risk Matrix Ecological Effects Very minor Minor Moderate Severe Very low Remotely likely/ weak/ insignificant Very low Very low Low Moderate spatial extent Low Rare/ mild/ occurs in a Very low Low Low Moderate localised/patchy spatial extent Moderate Exposure Exposure Low Low Moderate High Common/ intense/ occurs broadly High Frequent/ constant/ intense/ Moderate Moderate High Very high widespread Risk Description Very low No reasonable prospect that the objective will be affected by the event. Low Low priority for management by the benefits of the project could be increased by mitigation. The risk has the potential to significantly reduce the benefits of the project but it is not likely to cause Moderate significant environmental harm. There is a reasonable likelihood it will occur and will have harmful consequences or objectives will be High significantly compromised. Risk management is essential. Very high The risk is likely to occur and will have very harmful consequences. Risk management is essential.
Section 9.3 details the mitigation measures relevant for the moderate to very high level risks identified for Third Reedy Lake. The risk rating has then revised based on implementing the identified mitigation measures and using the same risk matrix in Table 20 above.
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Table 21: Benefit assessment for the objective of restoring Third Reedy Lake to an Intermittent Swampy Woodland Ecological objective Stressor Benefit description Exposure Ecological effect Benefit rating Description of objective Component of the regime that Potential improvement in current state Likelihood that the regime will provide the The degree to which t he ecological The significance potentially impact on the of the ecosystem environmental conditions to support the benefit objectives are met of the benefit ecological objective Habitat (Flora) Maintain fringing Black Flooding and drying Black Box health will be improved Minor- Black Box zone is above FSL level Meets objectives- The regime will not Moderate Box in healthy condition duration and frequency. by providing both a wetting and and therefore changes to water level will alter the current frequency of drying regime that is in line with not alter the current frequency of inundation and therefore will fulfil the the requirements of Black Box inundation (unless overbank flooding ecological objective of maintaining (Roberts and Marston, 2011). occurs). However potential for current condition. groundwater interactions through changed water level which may impact on zone. Increase recruitment Flooding and drying Drying allows establishment of Red Strong- The regime will promote both the Meets objectives- The regime will Very high (and establishment of duration and frequency. Gum seedlings (under assumption establishment (establishment regime) and promote conditions suitable for River River Red Gums in bed that there is appropriate seed long term maintenance (long term regime) Red Gum establishment and long term of wetland source available). Health of trees is of River Red Gums. maintenance. However there may be (Establishment phase) maintained through an appropriate the need for active planting of Red cycle of wetting and drying Gums due to low seed bank). (Roberts and Marston, 2011). Increased diversity of Flooding and drying Drying will allow understory Moderate - The regime is on the maximum Meets objectives- An increase in High understory vegetation duration and frequency. vegetation to establish in wetland wetting frequency for species such as understory diversity will be facilitate by in bed of wetland body (expansion of Intermittent lignum (requires flooding once in every 3 water regime. This will provide Swampy Woodland). Variability in to 5 years for a duration of 3 to 7 months) increase habitat for native fauna. water level promotes diversity of however fluctuating water levels will vegetation (Rogers and Ralph, promote a diversity of understory species. 2011; Roberts and Marston, 2011). The regime will see an expansion in Intermittent Swampy Woodland zone which currently supports the majority of significant flora species. Fauna communities Successful breeding of Timing, duration and depth Flooding acts as a stimulus for Moderate (long term) - Waterbird Meets objectives (long term) - Aims to high waterbirds of flooding and drawdown breeding in most waterbirds. Depth breeding will be facilitated by increased promote Red Gum establishment and (long term) as well as habitat and duration of flood water as well nesting sites (however lag time until full diverse understory which will provide (identified in ecological as drawdown impact on the benefit is realised) and feeding additional nesting sites. objectives 1, 2 and 3). success (Rogers and Ralph, 2011). opportunities (productive drawdown and wetting phases).
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Ecological objective Stressor Benefit description Exposure Ecological effect Benefit rating Increased opportunistic Wetting and drying regime Wetlands are highly productive Strong- The regime promotes increased Meets objectives- Variability in water Very high waterbird feeding will expose bed of wetland during the re-wetting and feeding opportunities through a diversity level will increase food sources opportunities increasing waterbird drawdown phase (i.e. organic of vegetation types. This may facilitate an feeding opportunities upon matter, insects, shoots, seeds etc) increase in the diversity of waterbirds re-wetting. (Rogers and Ralph, 2011). utilising the site. Drawdown phase may result in increased density of fish promoting high fish eating waterbird use. Increased opportunistic Wetting and drying Exposing the bed will promote Minor- The regime will promote the Partially meets objectives- The regime Low turtle and frog feeding duration and frequency- nutrient cycling and accumulation benefit upon re-wetting but the likelihood will only meet the objectives if and breeding opportunistic frog and of organic matter and insects which that benefit will be supported is dependent connectivity (between neighbouring turtle feeding and breeding will increase feeding opportunities on connectivity between wetlands. wetlands) is maintained (i.e. via aquatic opportunities. upon re-wetting (Mitch & or well vegetated drainage line). Gosselink, 2000). For example: Common long-necked turtles prefer ephemeral backwaters. Process Restore ecological Wetting and drying will Increased nutrient cycling, organic Strong- Variable water level with drying Meets objectives- Ecological processes Very high process associated with promote a range of matter, germination and will facilitate the benefit. associated with drying/wetting will be intermittent drying ecological processes. vegetation growth are promoted restored under regime. with wetting and drying (Mitch and Gosselink, 2000; Gawne and Scholz, 2006). Maintain connectivity Flooding and drying (at Connectivity allows dispersal of Dependent on Bypass infrastructure. Refer to KBLIP Landscape Scale Consideration Unknown between neighbouring target zone) duration and seeds, micro and macroorganisms, Report (North Central CMA, 2014). wetlands frequency. fish, frogs and turtles. Also maintains water quality through exchange of water.
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Table 22: Risk assessment for the objective of restoring Third Reedy Lake to Intermittent Swampy Woodland End Point Stressor Risk description Exposure Ecological effect Rating Indicator Aspects of the water Biological or physical effect of the stressor on Exposure of the endpoint to the stressor Potential effect on the stressor on the endpoint Significance regime that potential the endpoint of the risk affect the endpoint Habitat Black Box Reduced flooding/ • Poor Black Box health due less Low - Water level does not currently extend higher Moderate – no improvement in the health of Low fringe increased drying flooding/lower water level in wetland enough to provide Black Box with appropriate the Black Box zone to inability to flood • Tree death watering regime, therefore changes to water level (except during unregulated flooding events). • Low/ no recruitment within wetland will not impact on this zone. River Red Reduced flooding/ • flooding not provided during optimal Low- prescribed regime aims to promote conditions Very minor- The regime aims to promote Very low Gum increased drying period for growth response suitable for River Red Gum establishment and long conditions suitable for River Red Gums. • grazing of saplings (less recruitment) term health. Grazing (i.e. rabbits, kangaroos) will increase during dry phase however River Red Gums are known to colonise in large numbers so grazing may prove beneficial to reducing density. Excess germination • Red Gums can over colonise aquatic Moderate - It is likely that a high density of River Red Minor- Over colonisation of River Red Gums Low and establishment zones suppressing other wetland Gums saplings will establish under the establishment will result in decline in species richness and of River Red Gums vegetation water regime. will impact on feeding, breeding and shelter opportunities (Bren, 1992). The proposed regime includes a long term phase where conditions may be too dry for further Red Gum establishment. Long history of • Lack of recruitment due to no/low Moderate- It is likely that there will not be a viable Moderate - There is a stock of mature Moderate inundation existing seed bank seed bank present in the wetland body due to fringing River Red Gums at Third Reedy. • Establishment of exotic/ fast recruiting prolonged inundation. When conditions are favourable River Red species Gum reproduces and germinates readily (Roberts & Marston, 2011). Native Drying of flood • Reduction of some native flora due to Low - regime will impact on current assemblage of Minor- the regime should positively impact Low understory dependent species their dependence on permanent native flora (i.e. Tall Marsh) however low diversity is on the diversity and abundance of vegetation regime (i.e. Tall Marsh vegetation) already present in wetland body due to permanent understory species in the wetland body. It is • Increase in salt tolerant species inundation and therefore regime will improve likely that Tall Marsh will be lost from the diversity of understory. system however this EVC is the result of a modified water regime (would not have occurred under the natural water regime for Third Reedy) and its habitat function will be replace by other species.
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End Point Stressor Risk description Exposure Ecological effect Rating Impact of changed • Tall Marsh species (Branching Low- Tall Marsh zone should not be negatively Very low- the regime will not reduce the Very low regime on Groundsel) impacted by the changed regime. extent of this EVC nor should it impact on significant species Branching Groundsel • Intermittent Swampy Woodland Very low- the Intermittent Swampy Woodland zone Very low- the regime is likely to improve the Very low species (Brown Beetle-grass, Dark should not be negatively impacted by the changed condition and distribution of this EVC, which Roly-poly, Flat-top Saltbush, Short regime. In fact the zone should expand further out should facilitate increased opportunities for Water-starwort, Spiny Lignum, Twin- into the wetland bed. significant species. leaf Bedstraw) Weeds Promotion of • Establishment of competitive native Moderate- some species are promoted through Severe- The current growth/spread of High competitive native emergent species (i.e. Typha, intermittent flooding. For example Typha have been species such as Typha is suppressed under species or exotics Phragmites) that suppress native identified as a significant problem in other wetlands the current permanent regime. It is likely to (i.e. summer understory vegetation and degrade within the Kerang Wetlands Ramsar Site (i.e. increase under an intermittent regime and flooding and damp habitat (less diversity) Johnson Swamp and Hird Swamp) that have may reduce growth of native flood- soils) • Establishment of introduced species to intermittent watering regimes (Dalby-Ball et al. dependent understory species (i.e. sedges, colonise areas previously inundated 2000). Drying of wetland will also allow weeds such rushes, grasses, herbs) including rare and (i.e. Box Thorn and Patterson’s Curse) as Box Thorn, Patterson’s Curse to colonise. threatened species. Terrestrial weeds pose creating dense monoculture stands. less of a problem as drowning will occur • Loss of grazing habitat for waterbirds upon re-wetting. Connectivity • movement of weed propagules Low- system is already connected so increased Minor- spread of weeds throughout complex Low facilitates spread of throughout system spread is unlikely. is a minor issue as current connectivity weeds already facilitates this. Fauna communities Waterbirds Food availability • reduction in area for deep water Moderate - The regime will impact on the current Moderate- although a change will occur Moderate impacted by foragers assemblage of waterbirds through altering the type there will be increased feeding opportunities changed regime • reduction in fish (if no connectivity) habitat, food and food its availability (i.e. timing, (opportunistic) during productive re-wetting • change in composition of duration, and frequency). and drawdown phases. Also deep water nesting/resting habitat (i.e. loss of tall habitat is abundant within the Kerang Lakes. marsh habitat)
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End Point Stressor Risk description Exposure Ecological effect Rating Successful breeding • increased exposure to predators High- Most waterbirds require approximately 7-10 Moderate - there is uncertainty regarding High and fledging • insufficient flooding duration to months of inundation to support breeding. Some how particular species will respond to impacted by timing, support Colonial nesting waterbirds breed mid to late spring while others start later. changed regime. There is a risk that some duration and • nest abandonment or unsuccessful Appropriate water level needs to be maintained species will breed late in the season and frequency of fledging through insufficient flooding throughout breeding and fledging stage to ensure duration of watering will not be adequate wetting and drying duration success (Rogers and Ralph, 2011). Under current (without impacting on vegetation by • insufficient food resources regime waterbird breeding is not limited by this extending wetting phase). There is also the stressor. potential for nest abandonment through rapidly falling water levels. Recession needs to be adaptively managed carefully to optimise breeding. Flooding events • Waterbirds breed in small numbers Moderate - The regime will potentially result in Moderate- small and intermittent breeding Moderate provided in the when triggered by flooding/rainfall inundation in low rainfall years. events may help sustain local populations absence of The proposed regime will support fast and early but may not contribute to regional regional/ climatic breeders (i.e. waterfowl and birds with broad populations. Water regime should be triggers requirements) however specific requirements (i.e. managed in line with regional climatic egrets) may be more sensitive to regional conditions. conditions. Impact of changed • Brown Treecreeper Low- regime should not impact significantly on Very minor- the regime should not Very low regime on Brown Treecreeper as the species is reliant on negatively impact on Brown Treecreeper. It is significant wetland woodland vegetation for nesting, feeding (insects) likely that the regime will promote improved dependent species and breeding (Blakers et al . 1984). conditions for the species in the long term through an increase in River Red Gum habitat (Blakers et al. 1984). • Caspian Tern Moderate- Caspian Terns feeds primarily on fish Moderate- There is little evidence of Caspian Moderate which will be impacted by the proposed regime Terns breeding at inland wetlands and it is (Rogers & Ralph, 2010). Caspian Tern has not been therefore assumed that their presence at recorded at Third Reedy Lake since 1998 (see Section Third Reedy Lake is primarily for feeding. 5.3). Feeding will be impacted however this will be opportunistic as conditions will be improved during the drawdown phase when the concentration of fish is highest (Rogers & Ralph, 2011). Caspian Tern will not be present during dry phase.
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Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
End Point Stressor Risk description Exposure Ecological effect Rating • Eastern Great Egret Moderate - Eastern Great Egrets prefer permanent Minor to moderate - although the regime will Low - waterbodies, but also frequent shallows of deep shift the wetland from permanent to moderate permanent wetlands and semi-permanent swamps. intermittent an increase in the diversity of The proposed regime will move the site to an littoral zone vegetation as well as nesting intermittent wetland, which will also impact on fish and breeding habitat (i.e. flooded trees) will which is their primarily food source (Rogers & Ralph, make Third Reedy Lake a more desirable 2011). breeding location during wet phases. • Hardhead Moderate- Hardheads prefer wetlands with Minor to moderate- although the regime will Low- abundant aquatic vegetation and deep water for reduce the depth of the wetland (reducing moderate foraging. The regime will increase the variability of open water foraging opportunities) it will the wetland reducing open water opportunities increase the diversity of vegetation which is (Rogers & Ralph, 2011). Hardhead has not been important for nesting. recorded in Third Reedy Lake since 2006 (See Section 5.3). • Musk Duck High- Musk Ducks are almost entirely aquatic and Minor to moderate- although the regime Moderate- prefer stable conditions with abundant aquatic does not align with the requirements of high vegetation. They nest over deep water and dive up Musk Duck, periodic drying may increase the to 6m in search of aquatic invertebrates (Rogers & productivity of the preferred food sources of Ralph, 2011). The proposed regime will result in a Musk Duck (i.e. invertebrates). This may complete drying of the wetland which does not align encourage Musk Ducks to breed at Third with the requirements of the species. Musk Duck has Reedy Lake and may increase breeding not been recorded in Third Reedy Lake since 2006 success if water levels are retained during (See Section 5.3). fledging (Rogers & Ralph, 2011). • Nankeen Night Heron Low to moderate- Nankeen Night Herons are Minor - Crome (1988) (cited in Rogers & Low - nocturnal feeders that utilise well vegetated littoral Ralph, 2011) documented that Nankeen moderate zones with tall emergent vegetation. Although they Night Heron is triggered by flooding and that prefer permanent wetlands they have been there is an increase in success following a observed on temporary waterbodies. The nest in few months of drying. The regime will trees, shrubs and reed beds and feed on aquatic promote these conditions, particularly animals, particularly fish, frogs and insects (Rogers & stimulating flooding upon re-wetting. Ralph, 2011). The proposed regime may impact on feeding opportunities.
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Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
End Point Stressor Risk description Exposure Ecological effect Rating • Pied Cormorant High- Pied Cormorants prefer stable water levels Moderate- the regime will reduce the High typical of permanent freshwater wetland systems occurrence of Pied Cormorant breeding and and feed primarily on fish and crustaceans. The use of Third Reedy Lake. However they are regime will result in a drying phase which will impact stimulated by flooding, and therefore it is on fish (Rogers & Ralph, 2011). likely that increased use of the site will occur during re-fill events. They prefer to breed in trees, particularly those within swamps. The expansion of River Red Gum into the body of the wetland is an ecological targeted of the proposed regime (Rogers & Ralph, 2011). • Royal Spoonbill Low- Royal Spoonbills are known to utilise both Minor- The regime will promote appropriate Low permanent and ephemeral wetlands and like semi- conditions for Royal Spoonbill breeding and aquatic herbs or emergent vegetation. They forage feeding during wet phase. Crome (1988) in shallow water feeding on fish and insects and (cited in Rogers & Ralph, 2011) found that roost and nest in trees, shrubs, reeds, rushes and there was an increase in breeding success of lignum (Rogers & Ralph, 2011). The requirements of Royal Spoonbills after an intermittent Royal Spoonbill align well with the proposed regime. wetland was completely dried. This process promotes increased productivity of chironomids and other insects that enhance breeding success during wet phases. • White-belled Sea Eagle Moderate- The regime will impact on breeding Minor to moderate - Habitat for White- Low- opportunities during the dry phase however when bellied Sea-Eagles will not be impacted by Moderate dry feeding opportunities will be limited. the changed regime. In fact in the long term there may be an increase in nesting opportunities (i.e. more River Red Gums). Although White-bellied Sea-eagles are opportunistic carnivores (eating a mix of birds, mammals, reptiles and fish) they may not breed during dry phases due to reduced feeding opportunities (particularly fish) (DSE, 2003). Turtles Reduced flooding/ • Inability to move to more favourable Moderate to high - species able to move to nearby Moderate- if species are unable to move Moderate- increased drying conditions Middle Reedy Lake will be impacted less than species there is a high risk of population loss, high • Lack of habitat (i.e. Common Long-necked Turtle) that are however if movement is facilitated by • Turtle death dependent on the permanent nature of the wetland connectivity between Middle and Third • Impact on significant species (i.e. Murray River Turtle). Reedy conditions may be improved during re-wetting phase.
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Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
End Point Stressor Risk description Exposure Ecological effect Rating Frogs Reduced flooding/ • Inability to move to more favourable High- Drying phase will impact on a number of frog Moderate- the frog species present at Third High increased drying conditions species who are reliant on the permanent nature of Reedy has a range of different requirements. • Lack of habitat the wetland. None are listed as threatened. Favourable conditions will be promoted upon re-wetting (increase feeding opportunities). Native fish Lack of connectivity • Inability to move to more favourable Moderate - likelihood of impact is dependent on Severe - connectivity between wetlands is High allowing movement conditions upon drying ability for there to be movement between wetlands. paramount in ensuring fish can move to prior to drying • Fish death refuge sites upon drying. Upon re-wetting phase • reduction In species dependent on Third Reedy will be a highly productive current regime environment for fish. Inadequate cues to • Fish fail to move out of wetland upon Moderate- some fish require cues to prompt them Moderate- slow recession is likely to prompt Moderate stimulate drying phase to move to more favourable conditions (i.e. flow fish movement, however some species (i.e. movement • Fish death cues, water temperature etc) (Rogers and Ralph, small bodies may not move). Some fish may 2011). be trapped in the wetland. Impact of changed • Freshwater Catfish Moderate- The proposed regime will not Moderate- there is little evidence to suggest Moderate regime on permanently support this species due to a complete that Freshwater Catfish migrate. Adults make significant species drying phase. Freshwater Catfish has not been limited and somewhat random movements recorded in Third Reedy Lake since 1981 (See Section in their local environment and therefore 5.3). local habitat disruptions (i.e. drying as per the prescribed regime) are the most significant risk to the species if still present in Third Reedy Lake. Risk rating reduced due to the likelihood of their presence in the wetland being low. • Murray Hardyhead Moderate- Although Murray Hardyhead has not Sevree- Murray Hardyhead is a critically High been recorded in Third Reedy Lake it should be endangered fish species that is facing considered due to its presence in neighbouring extinction due to loss of appropriate habitat. Middle Reedy Lake (See Section 5.3). The proposed A drying regime will result in the loss of the regime will not permanently support this species due species if they are unable to move to to a complete drying phase. neighbouring wetlands. This risk rating would be reduced if further investigations reveal that the species is not present at Third Reedy Lake.
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Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
End Point Stressor Risk description Exposure Ecological effect Rating • Silver Perch Moderate- The proposed regime will not support Moderate - Silver Perch are known to move Moderate this species due to a complete drying phase. Silver however a drying regime will result in the Perch has not been recorded in Third Reedy Lake loss of the species if they are unable to move since 1981 (See Section 5.3). to neighbouring wetlands (Rogers & Ralph, 2011). Risk rating reduced due to the likelihood of their presence in the wetland being low. • Unspecked Hardyhead Moderate- The proposed regime will not Moderate to severe- The small size of the Moderate- permanently support this species due to a complete species may limits its ability to move to more high drying phase. favourable conditions. • Golden Perch Moderate- The proposed regime will not Minor to moderate-Golden Perch is stocked Low- permanently support this species due to a complete in neighbouring First Reedy Lake and Moderate drying phase. therefore a local loss at Third Reedy Lake would not put significant pressure on the community. The species is known to move within an home range of approximately 100m, and therefore assuming connectivity to neighbouring wetlands is maintained, the species should be able to move to more favourable conditions (Rogers & Ralph, 2011). • Murray Cod Moderate- The regime will subject Murray Cod to a Moderate-Murray Cod is stocked in Moderate complete drying phase. Murray Cod has not been neighbouring First Reedy Lake and therefore recorded in Third Reedy Lake since 2006 (See Section a local loss of the species may not put 5.3). significant pressure on their entire community. Further recent investigations of Murray Cod suggest that the species may undertake spawning and non-spawning movement of 10s-100s km (PIRSA, 2013). This may mean that Murray Cod will move when conditions become favourable (and assuming no barriers to movement). However the species is also known to be territorial and may return or persist at certain locations for long periods (Rogers & Ralph, 2011).
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Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
End Point Stressor Risk description Exposure Ecological effect Rating Non-native Conditions favour • increased competition for resources Low- many exotics are able to tolerate variability Moderate- exotic species such as carp will Low fish non-native species • water quality issues (Rogers and Ralph, 2011). However as per above, the reduce abundance of aquatic vegetation. • Habitat damage (i.e. increased likelihood of impact is reduced due to drying of They will also compete with natives for turbidity, shoreline erosion) wetland. resources and can cause water quality issues (i.e. turbidity) (Rogers & Ralph, 2011). Processes Connectivity Inappropriate • Inability for species to move to Unknown Dependent on Bypass infrastructure. Refer to KBLIP Landscape Scale Consideration Report (North infrastructure or more favourable conditions Central CMA, 2014). management • Lack of seed dispersal • Lack of flushing • Water quality issues Water Increased • possible impact on flora diversity Moderate - warm, shallow water (i.e. during Moderate - the process of warm, shallow Moderate quality temperature favouring temperature tolerant summer) facilitates proliferation of weed species and water during drawdown phase is a natural variability species (i.e. facilitate rapid growth) may cause increased primary productivity (i.e. blue- occurrence and management should focus • increased primary productivity green algae blooms). on preventing spread of species such as Typha. High litter levels • depleted dissolved oxygen and Low - conditions are likely to occur in poorly Minor- A variety of biological and chemical Low creating high reduced pH can cause death of aquatic circulated area (Third Reedy will have maintained processes will be restored by drying the organic load and biota connectivity) however likelihood increases in wetland. depressing summer with warmer water. dissolved oxygen levels. Nutrient cycling • altered nutrient and carbon Low- nutrient cycling will be increased by drying Moderate - reduced nutrient cycling would Low transport and subsequent reduction phase through accumulation of organic matter, soil impact on the ability of the wetland to act as in productivity aeration, microbial activity etc (Mitsch and a carbon sink. Further to this there would be • reduced abundance of flood Gosselink, 1993) a decrease in productivity and food dependent food sources availability. Soils Increase drying of • reduced water quality Moderate - the slow recession and duration of the Severe - exposure of bare soil has the High previously • erosion and loss of top-soil if no drying phase may facilitate establishment of potential to cause loss of topsoil and inundated soils vegetation establishment terrestrial vegetation in the wetland. Third Reedy turbidity upon re-wetting. • aesthetically displeasing was identified to have the second highest risk of acid • acid sulfate soils sulfate soils (out of all KLBIP wetlands) (URS, 2013).
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Kerang Lakes Bypass Investigation Project Technical Report –Third Reedy Lake
End Point Stressor Risk description Exposure Ecological effect Rating Ground- Drying phase • increased salinity during High - it is possible that groundwater intrusion may Severe- Groundwater intrusion would Very High water resulted in saline summer/autumn due to saline occur at Third Reedy Lake during drying phase significantly impact on the flora and fauna groundwater groundwater intrusion (driven by regional climate) when the regional supported by the wetland. intrusion / Changes • increase stratification of water groundwater levels are high (URS, 2013). This could to water salinity • increase salinity impacting on be exacerbated by accumulation of salt in the bed of Note: This may benefit some native species level aquatic flora and fauna the wetland during each cycle resulting in a long (i.e. Murray Hardyhead) who can tolerate • potential infiltration of saline term increase in wetland salinity. high salinity levels. groundwater into the wetland during drying cycles • death of salt intolerant species Establishment of • Exposure of soils to oxygen creating Moderate - There is a potential for ASS to form in Severe- ASS have the potential to severely Very High Acid Sulfate Soils ASS soils Third Reedy Lake (URS, 2013) although additional impact on the flora and fauna of Third Reedy (ASS) • Released and mobilised during sampling is required to better understand the risk Lake. inundation events from ASS.
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KLBIP Technical Report – Third Reedy Lake
9.3. Mitigation Assessment A number of risks have been identified as part of the risk assessment for the objective of restoring Third Reedy Lake to an Intermittent Swampy Woodland (refer to Section 8.3). Mitigation actions and further assessment for each moderate, high or very high risk are considered as part of the risk mitigation in Table 23.
• Mitigation actions: risk mitigation measures have been recommended for Third Reedy Lake to reduce the risk in providing a modified watering regime.
• Further assessment: whether significant species are exposed or if the surrounding environment / wetland habitats would provide refuge for the environmental values exposed to the risk.
A new risk rating is provided in Table 23; however some risks require further assessment.
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Table 23: Modified risk assessment End Point Stressor Risk description Initial Risk Mitigation Actions / Further Modified Exposure Modified Ecological effect Modified Rating Assessment Rating Indicator Aspects of the Biological or physical effect of the Significance • Actions recommended to reduce Exposure of the endpoint to the Potential effect on the stressor on Significance water regime that stressor on the endpoint of the risk level of risk stressor the endpoint of the risk potential affect • Consideration of surrounding the endpoint environment and species significance Habitat River Red Long history of • Lack of recruitment due to Moderate • Mature surrounding Red Gums Low- Active management Low - There is a stock of mature Low Gum inundation no/low existing seed bank to offer seed source. including planting and fringing River Red Gums at • Establishment of exotic/ fast • Active planting of Red Gums and dispersal of seeds and control Third Reedy. When conditions recruiting species manual dispersal of seed if of weeds will allow are favourable River Red Gum required establishment of Red Gums. reproduces and germinates • Monitor the establishment of readily (Roberts & Marston, species as part of adaptive 2011). management process • Undertake appropriate weed Re-establishment of Red Gums control where relevant is well understood and applied Weeds Promotion of • Establishment of competitive High • Provide a water regime that Low- Active management will Low- Active management will Low competitive native emergent species (i.e. encourages a diversity of plant ensure a diversity of species. ensure a diversity of species. native species Typha, Phragmites) that species to establish or exotics (i.e. suppress native understory • Monitor the establishment of summer vegetation and degrade species as part of adaptive flooding and habitat (less diversity) management process damp soils) • Establishment of introduced • Undertake appropriate species to colonise areas vegetation control where previously inundated (i.e. relevant Box Thorn and Patterson’s Curse) creating dense monoculture stands. • Loss of grazing habitat for waterbirds
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End Point Stressor Risk description Initial Risk Mitigation Actions / Further Modified Exposure Modified Ecological effect Modified Rating Assessment Rating Species Waterbirds Food availability • reduction in area for deep Moderate • Wetlands within and Low - Food available at other Minor- Waterbirds will move to Low impacted by water foragers surrounding the Kerang Lakes wetlands in surrounding surrounding environments - the changed regime • reduction in fish (if no provides a diversity of habitat Kerang Lakes. Kerang Lakes have many connectivity) appropriate wetlands for • change in composition of feeding habitat. nesting/resting habitat (i.e. loss of tall marsh habitat) Successful • increased exposure to High • Ensure during wetting period Low- Maintaining water Moderate - Maintaining water Low breeding and predators that appropriate inundation regime and habitat regime and habitat fledging • insufficient flooding duration duration is maintain to allow bird improvement will provide improvement will provide impacted by to support Colonial nesting breeding to be completed. opportunities for waterbird opportunities for waterbird timing, duration waterbirds • Proposed Water regime will breeding breeding and frequency • nest abandonment or encourage greater diversity of of wetting and unsuccessful fledging habitat to support future Providing the appropriate drying through insufficient flooding breeding events. water regime and habitat will duration • Most waterbirds require not guarantee bird breeding • insufficient food resources approximately 7-10 months of events as other factors inundation to support breeding. including flooding in other part Some breed mid to late spring of Australia and available food while others start later. will also influence bird breeding Appropriate water level needs to be maintained throughout breeding and fledging stage to ensure success (Rogers and Ralph, 2011). Flooding events • Waterbirds breed in small Moderate • Ensure watering events align Low - Regional Climatic Moderate- Water regime Low provided in the numbers when triggered by regional climatic conditions conditions considered in should be managed in line with absence of flooding/rainfall including flooding events. wetting and drying regime. regional climatic conditions. regional/ climatic triggers
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End Point Stressor Risk description Initial Risk Mitigation Actions / Further Modified Exposure Modified Ecological effect Modified Rating Assessment Rating Impact of • Caspian Tern Moderate • If breeding, ensure adequate Moderate- Feeding Minor- Species can move to Low changed regime duration opportunities will be reduced more appropriate surrounding on significant • Providing water between during dry phase environments - the Kerang species September- February Lakes have a diversity of • Wetlands within and wetlands types for feeding. surrounding the Kerang Lakes provides a diversity of habitat types and food sources. • Eastern Great Egret Low- • If breeding, ensure adequate Moderate-Breeding and Minor- Species can move to Low moderate duration feeding opportunities will be more appropriate surrounding • Providing water between reduced during dry phase environments - the Kerang September- May Lakes have a diversity of • Wetlands within and wetlands types for feeding and surrounding the Kerang Lakes breeding habitat. provides a diversity of habitat types and food sources.
• Hardhead Low- • If breeding, ensure adequate Moderate-Breeding and Minor- Species can move to Low moderate duration of 5-8 months feeding opportunities will be more appropriate surrounding • Providing water between August reduced during dry phase environments - the Kerang and December Lakes have a diversity of • Wetlands within and wetlands types for feeding and surrounding the Kerang Lakes breeding habitat. provides a diversity of habitat types and food sources. • Musk Duck Moderate- • If breeding, ensure adequate High- Musk Ducks are entirely Minor- Species can move to Moderate high duration of 6-8 months aquatic and prefer stable more appropriate surrounding • Providing water between ideally conditions. Therefore environments - the Kerang between September and breeding and feeding Lakes have a diversity of December opportunities will be reduced wetlands types for feeding and • Wetlands within and during dry phase. breeding habitat. Periodic surrounding the Kerang Lakes drying may also improve provides a diversity of habitat conditions during wet phases. types and food sources.
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End Point Stressor Risk description Initial Risk Mitigation Actions / Further Modified Exposure Modified Ecological effect Modified Rating Assessment Rating • Nankeen Night Heron Low- • If breeding, ensure adequate Moderate-Breeding and Minor- Species can move to Low moderate duration of 12 months feeding opportunities will be more appropriate surrounding • Providing water between reduced during dry phase environments - the Kerang September and February Lakes have a diversity of • Wetlands within and wetlands types for feeding and surrounding the Kerang Lakes breeding habitat. provides a diversity of habitat types and food sources. • Pied Cormorant High • If breeding, ensure adequate High-Breeding and feeding Minor- Species can move to Moderate duration opportunities will be reduced more appropriate surrounding • Providing water between during dry phase as Pied environments - the Kerang September- May Cormorants prefer stable Lakes have a diversity of • Wetlands within and water levels and feed wetlands types for feeding and surrounding the Kerang Lakes primarily on fish. breeding habitat. Periodic provides a diversity of habitat drying may also improve types and food sources. conditions during wet phases. • White-bellied Sea Eagle Low- • Wetlands within and Moderate-Breeding and Minor- Species can move to Low moderate surrounding the Kerang Lakes feeding opportunities will be more appropriate surrounding provides a diversity of habitat reduced during dry phase. environments - the Kerang types and food sources. Lakes have a diversity of wetlands types for feeding and breeding habitat. Turtles Reduced • Inability to move to more Moderate • Turtle species particularly Low - Monitoring and if Low- An integrated Low flooding/ favourable conditions to high Common Long-necked Turtle are required translocation will management approach for increased • Lack of habitat likely to move to nearby reduce risk to turtle species. turtle species will minimise any drying • Turtle death wetland/Lake if drying phase is impacts from changes to water • Impact on significant species introduced (Howard et al. 2013). regime. Ensure appropriate pathway to assist movement. • Murray River Turtle movement is less understood and may require translocation. • Monitor and implement translocation if required. • Consider managing external threats including fox predation of eggs.
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End Point Stressor Risk description Initial Risk Mitigation Actions / Further Modified Exposure Modified Ecological effect Modified Rating Assessment Rating Frogs Reduced • Inability to move to more High • Barking Marsh Frog, Peron’s Tree High- Drying phase will Minor- Frog species present at Moderate flooding/ favourable conditions Frog and Spotted Marsh Frog are impact on a number of frog Third Reedy Lake have a range increased • Lack of habitat not significant species. They also species who are reliant on of different requirements. drying • No significant species have have the ability to move to other the permanent nature of the None are listed as threatened. been identified in Third permanent water habitats in wetland. Favourable conditions will be Reedy Lake surrounding environment. promoted upon re-wetting (increase feeding opportunities).
Native fish Lack of • Inability to move to more Moderate- • Implement filling regime that Moderate - Mitigation actions Moderate- An integrated Moderate connectivity favourable conditions upon High provides connectivity. (e.g. translocation and fish management approach for allowing drying • Monitor and implement passage) will reduce risk to native fish species will minimise movement prior • Fish death translocation if required for key native fish species; however most impacts from changes to to drying phase • reduction In species species (i.e. Murray Hardyhead) it is unlikely that all the water regime. However the dependent on current • Ensure fish passage through the individuals could physically potential two EPBC listed regime Reedy Lakes/Loddon be translocated. species (Murray Cod and • Impact on significant species River/Pyramid Creek Murray Hardyhead) may be (Freshwater Catfish, Murray impacted significantly by the Hardyhead, Silver Perch, changed regime. Unspecked Hardyhead, Golden Perch, Murray Cod)
Inadequate • Fish fail to move out of Moderate • Implement filling regime that Low - Mitigation actions (e.g. Low- An integrated Low cues to wetland upon drying phase provides connectivity and a providing watering cues, fish management approach for stimulate • Fish death trigger for fish movement out of passage and translocation) native fish species will minimise movement Third Reedy Lake prior to drying. will reduce risk to native fish any impacts from changes to • Monitor and implement species. water regime. translocation if required for key species. • Ensure fish passage through the Reedy Lakes/Loddon River/Pyramid Creek
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End Point Stressor Risk description Initial Risk Mitigation Actions / Further Modified Exposure Modified Ecological effect Modified Rating Assessment Rating Process Water Increased • possible impact on flora Moderate • Natural process – mitigation Moderate - Warm, shallow Low- Weed management will Low quality temperature diversity favouring actions, including weed water facilitates proliferation ensure a diversity of aquatic variability temperature tolerant species management post wetland of weed species and may plants. (i.e. facilitate rapid growth) drying will manage impacts. cause increased primary • increased primary productivity (i.e. blue-green productivity algae blooms). However in the long term there is the potential for a lowering of water temperature through increased tree and shrub cover. Soils Increase drying • reduced water quality High • Establishment watering regime Low- Active management Low to moderate – there is Low of previously • erosion and loss of top-soil recommended to promote including planting and some risk in the short term inundated soils if no vegetation River Red Gum establishment dispersal of seeds will (loss of soils), however once establishment and other wetland plants (refer manage top soil loss. wetland plants establish this • aesthetically displeasing to Section 4.9). risk will be reduced. • acid sulfate soils • Active planting of wetland vegetation (e.g. Club Rush) during drying phase and manual dispersal of seed if required • Monitor the establishment of species as part of adaptive management process
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End Point Stressor Risk description Initial Risk Mitigation Actions / Further Modified Exposure Modified Ecological effect Modified Rating Assessment Rating Ground- Drying phase • increased salinity during Very High • Adaptively manage the water Low - Surrounding Low- Groundwater intrusion Further water resulted in summer/autumn due to regime to ensure that wetland groundwater level will be will be minimised as there will assessment saline saline groundwater level is above groundwater considered in setting wetland be no or little gradient for is required groundwater intrusion levels. This could include level. groundwater to enter wetland. intrusion • potential infiltration of changes in the operation of the saline groundwater into Kerang Lakes by GMW (to be This water regime is likely to the wetland during drying documented in an Operations have impacts on other cycles Plan). ecological objectives and values • death of salt intolerant • Wetland flushing may be species required to maintain wetland salinity at levels appropriate to support ecological objectives. The volumes required to support flushing have not yet been determined and are highly dependent on wetland salinity levels • Additional modelling may be required to better understand how the water regime will change the groundwater. Establishment • Exposure of soils to oxygen Very High • Additional sampling is required N/A – additional sampling is N/A – additional sampling is Further of Acid Sulfate creating ASS soils to better understand the risk required before an required before an assessment assessment Soils of ASS. assessment can be made can be made is required
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9.4. Risk and mitigation summary As detailed in Table 23 there are a number of risks associated with the proposed watering regime that cannot be fully mitigated through management intervention. This includes loss of species such as Musk Duck, Pied Cormorant and native fish species which require permanent conditions. However in the broader region, the habitat provided by Third Reedy Lake is a relatively small contribution to the overall area that these species inhabit. Therefore neighbouring wetlands will still provide sufficient habitat for these species to flourish under the proposed regime. 10. Knowledge gaps A proposed wetland water regime has been derived for Third Reedy Lake based on the sites ecological values; however risks have also been identified in transitioning this wetland from a permanent freshwater lake to an Intermittent Swampy Wetland (one in three year watering regime). The following recommendations are required to understand some of the risks identified: • Development of an Environmental Watering Plan (EWP): The development of an Environmental Watering Plan (EWP) is recommended for Third Reedy Lake prior to the implementation of any water savings initiatives that will alter the current water regime. This will enable scientists and managers to work through an approved process to establish an environmental watering regime to protect and maintain the wetland’s environmental integrity. • Groundwater: there are risks associated with altering the current permanent regime at Third Reedy Lake which are largely related to the relationship between wetland levels and the level of the surrounding groundwater. Further investigations are required to estimate the salinity impacts of the proposed one in four filling regime and consideration of the salinity effects of implementing the above operating rules. A more detailed groundwater model may be required to better estimate the implications of an adaptive management approach. • Native fish: further fish investigations including the status of Murray Hardyhead at Third Reedy Lake may be required. Biosis (2013) identified this wetland as having suitable habitat for this species, although Sharpe (2014) failed to detect Murray hardyhead and noted that the key habitat conditions are not conducive to their proliferation • Acid Sulfate Soils: a more detailed Acid Sulfate Soils analysis is required to better understand the risk from drying the wetland, field investigations have not been undertaken to date. • Reptiles: the impact of drying Third Reedy Lake on Turtles (e.g. Murray River Turtle) and Frogs (e.g. Spotted Marsh Frog) is recommended. • Landscape scale: Third Reedy Lake has been assessed in isolation of the KLBIP, consideration of the wetland system and connectivity with the landscape is required.
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11. References Barker, J., Grigg, G., Tyler, M. (1995). A field Guide to Australian Frogs . Surrey Beatty and Sons, Chipping Norton. Biosis (2013). Kerang Lakes Fauna Assessment- Draft report. Prepared for the North Central Catchment Management Authority. Biosis Pty Ltd, Melbourne. Birdlife Australia (2013). BirdLife Australia database. Accessed 9 June 2013 from http://birdlife.org.au/ . Blakers, M., Davies, S. J. J. F., Reilly, P. N. (1984). The atlas of Australian Birds. Royal Australasian Ornithologist Union and Melbourne University Press, Melbourne. Bren, L. (1992). Tree invasion of an intermittent wetland in relation to changes in the flood frequency of the River Murray, Australia . Australian Journal of Ecology, Vol. 17, pp. 395-408. Brock M.A., Nielsen D.l., Shiel R.J., Green J.D. and Langley J.D. (2003). Drought and aquatic community resilience: the role of eggs and seeds in sediments of temporary wetlands . Freshwater Biology 48: 1207– 1218 cited in Roberts and Marston (2011). Clunie, P. (2010). Description of the ecological character of the Kerang Lakes Ramsar site . Department of Sustainability and Environment. Corrick, A.H., and Norman, F.I., (1980). Wetlands of Victoria I. Wetlands and waterbirds of the Snowy River and Gippsland Lakes catchment . Proceedings of the Royal Society of Victoria 91:1–15 Dalby-Ball, M., Roberts, J., Sainty, G. (2000). Plant Management in the Kerang Wetlands: a case study ofr Hird Swamp . Reported developed by Parks Victoria. DEPI (2013). Fish stock report . Retrieved 5 July 2013, from the Department of Environment and Primary Industries: http://www.dpi.vic.gov.au/fisheries/about-fisheries/fish-stocking-reporting . DEWHA (2008 ). National Framework and Guidance for Describing the Ecological Character of Australia’s Ramsar Wetlands. Module 2 of the National Guidelines for Ramsar Wetlands- Implementing the Ramsar Convention in Australia . Australian Government Department of Environment, Water, Heritage and the Arts, Canberra. DEWHA (2009). National guidance on notifying change in ecological character of Australian Ramsar Wetlands (Article 3.2). Module 3 of the National Guidelines for Ramsar Wetlands- Implementing the Ramsar Convention in Australia. Australian Government Department of Environment, Water, Heritage and the Arts, Canberra. DSE (2003). Flora and Fauna Guarantee Action Statement: White-bellied Sea-eagle . Department of Sustainability and Environment. Melbourne. DSE (2004). Kerang Wetlands Ramsar Site: Strategic Management Plan . Department of Sustainability and Environment, Melbourne. DSE (2005a). Index of Wetland Condition: Conceptual framework and selection of measures . Victorian Government, Melbourne. DSE (2005b). Advisory List of Rare or Threatened Plants in Victoria. Department of Sustainability and Environment, Victoria.
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DSE (2006). Kerang Lakes Ecological Character Description . Compiled by Pam Clunie, Department of Sustainability and Environment, Bendigo. DSE (2010). Kerang Wetland Ramsar Site Ecological Character Description . Department of Sustainability and Environment, Melbourne. DSE (2012a). Water and salinity regime and depth preference for Victorian wetland Ecological Vegetation Classes. Prepared for the Department of Sustainability and Environment. Pathways Bushland and Environment Consultants, Greensborough, Victoria. DSE (2012b). A field guide to Victorian Wetland Ecological Vegetation Classes for the Index of Wetland Condition 2 nd Edition . Department of Sustainability and Environment, Melbourne. DSE (2013). Advisory List of Threatened Vertebrate Fauna in Victoria. Department of Sustainability and Environment, Victoria. Ecological Associates (2010). Gunbower Forest Hipwell Road channel ecological benefit and risk analysis- final report. Prepared for the North Central Catchment Management Authority. Ecological Associates Pty Ltd, Malvern, SA. Gawne, B., Scholz, O. (2006). Synthesis of a new conceptual model to facilitate management of ephemeral deflation basin lakes. Lakes and Reservoirs: Research and Management , Vol. 11, pp. 177-188. Gippel, C. (2012). Preliminary hydrological modelling for Kerang Lakes bypass investigation project . Prepared for Goulburn-Murray Water. Fluvial Systems, Stockton, NSW. G-MW (2011). Third Reedy Lake- Bathymetric survey . Goulburn-Murray Water, Tatura, Victoria. G-MW (2010). Central Murray Operations – Operating Procedures . Goulburn-Murray Water, Tatura, Victoria. Hale, J., (2009). Northern Victoria Irrigation Renewal Project: Operation Impact Assessment on Wetlands of International Importance (Ramsar Wetlands). Report to Hydro Environmental, Jennifer Hale, Kinglake. Ho, S., Roberts, J., Cheers, G., Suitor, L. (2006). Development and application of an ecological monitoring and mapping program for targeted Kerang Lakes . Report prepared for the North Central Catchment Management Authority. Murray-Darling Freshwater Research Centre, Mildura. Howard, K., Stricker, H., Spencer, R.-J., & Beesley, L. (2013). Population demographics,abundance and movement of turtles within the Gunbower Lagoon System. Arthur Rylah Institute for Environment Research. Unpublished Client Report for the North Central Catchment Management Authority, Department of Sustainability and Environment, Heidelberg, Victoria. Hunt, T. L., Allen, M. S., Douglas, J. & Gason, A. (2010). Evaluation of a sport fish stocking program in lakes of the Southern Murray-Darling Basin, Australia. North American Journal of Fisheries Management, Vol. 30, pp. 805-811. KBR (2007). Assessment Framework of changed water management regimes on the health of the Kerang Lakes . Prepared for the Department of Sustainability and Environment. Kellogg Brown and Root, St Kilda. KBR (2011). Kerang Wetlands Ramsar Site: Ecological Character Description . Draft reported prepared for the Department of Sustainability, Environment, Water, Population and Communities, Kellogg Brown and Root, St Kilda.
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Kingsford, R.T. & Porter, J.L. (2006). Waterbirds and wetlands across Eastern Australia. Technical report prepared for the Department of the Environment and Heritage, Canberra. Lugg, A., Heron, S., Fleming, G., O’Donnell, T. (1989). Report to Kerang Lakes Area Working Group- Report 1: Conservation values of the wetlands in the Kerang Lakes Area. Department of Conservation Forest and Lands and Kerang Lakes Assessment Group. MDFRC (2010). Detailed Assessment of Acid Sulfate Soils in the Murray-Darling Basin: Protocols for sampling, field characterisation, laboratory analysis and data presentation . Murray-Darling Basin Publication No. 57/10, pp 58. Mitch, W. and Gosselink, J. (2000). Wetlands, Third Edition . John Wiley and Sons, New York. North Central CMA (2011). Kerang Lakes Water Savings Project Investigation – Literature Review. North Central Catchment Management Authority, Huntly. North Central CMA (2012). Alternative Water Regimes for Kerang Lakes Bypass Investigation Project – Phase 1. North Central Catchment Management Authority, Huntly. North Central CMA (2014). Kerang Lakes Bypass Investigation Project – Landscape Scale Considerations . Prepared for the Goulburn-Murray Water Connections Project, North Central Catchment Management Authority, Huntly, Victoria. O’Donnell, T (1990). Vegetation of the wetlands in the Kerang Lakes area. A report to Kerang Lakes Area Working Group (KLAG). Department of Conservation, Forest and Lands, Bendigo region. PIRSA (2013). PIRSA fisheries: Murray Cod . Retrieved 14 August 2013, from the Government of South Australia, Adelaide: http://www.pir.sa.gov.au/fisheries/recreational_fishing/target_species/murray_cod . Rakali (2013). Ecological Vegetation Class Assessment for the Reedy Lake system, Little Lake Charm and Racecourse Lake surrounding areas in the Kerang Wetlands Ramsar Site . Report prepared for the North Central Catchment Management Authority, Huntly. Ramsar (2005). The Criteria for Identifying Wetlands of International Importance. The Ramsar Convention on Wetlands . Ramsar, Iran, 1971. Roberts, J. and Marston, F. (2011). Water Regime for Wetland and Floodplain Plants: A Source Book for the Murray-Darling Basin . National Water Commission, Canberra, ACT. Rogers, K. & Ralph, TL. (Eds) (2011). F loodplain Wetland Biota in the Murray-Darling Basin: Water and Habitat Requirements . CSIRO Publishing, Collingwood, Victoria. Sharpe, C. (2014). Kerang Lakes Murray hardyhead Survey, March 2014. Final Report, CPS Environmental Research for the G-MW Connections Project. SKM (2006). Kerang to Little Murray Floodplain Management Plan- Assessment of Options . Report prepared for the North Central CMA, Huntly, Victoria. SKM (2010). Environmental water regime requirements of the Kerang Lakes. Reported prepared for Goulburn-Murray Water. Sinclair Knight Merz, Tatura. Tucker, P. Harper, M. Dominelli, S. van der Wielen, M.and Siebentritt, M. (2002). Your Wetland: Hydrology Guidelines. Department of Environmental Biology, University of Adelaide, Adelaide.
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URS (2013). Kerang Lakes Bypass Investigation Project: Hydrogeological Risk Assessment: Conceptual Model & Project Summary Report . Prepared for the Goulburn-Murray Water Connections Project. URS Australia, Tatura, Victoria. VEAC (2008). Identifying flood-dependent natural values on the Victorian floodplains of the River Murray and its tributaries. Prepared by the Victorian Environmental Assessment Council.
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Appendix A: Bathymetry
Height Area Volume (mAHD) (ha) (ML) 72.9 0.02 0.01 73.0 0.05 0.04 73.1 0.12 0.12 73.2 11.11 2.67 73.3 76.53 38.61 73.4 124.59 135.01 73.5 152.59 272.63 73.6 174.32 435.64 73.7 187.41 616.31 73.8 199.02 809.59 73.9 206.59 1012.64 74.0 211.51 1221.77 74.1 215.21 1435.18 74.2 218.42 1652.0 74.3 221.63 1872.03 74.4 224.86 2095.28 74.5 228.10 2321.76 74.56 (FSL) 230.13 2459.23 74.6 231.50 2551.56 74.7 233.67 2784.18 74.8 235.63 3018.84 74.9 237.51 3255.41 75.0 239.21 3493.79 75.1 240.67 3733.75 75.2 241.97 3975.08 75.3 243.17 4217.65 75.4 244.29 4461.39 75.5 245.35 4706.21 ----- Denotes cross section referred to in Figure 5 and Figure 9.
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Height Area Volume (mAHD) (ha) (ML) 72.9 0.02 0.01 73.0 0.05 0.04 73.1 0.12 0.12 73.2 11.11 2.67 73.3 76.53 38.61 73.4 124.59 135.01 73.5 152.59 272.63 73.6 174.32 435.64 73.7 187.41 616.31 73.8 199.02 809.59 73.9 206.59 1012.64 74.0 211.51 1221.77 74.1 215.21 1435.18 74.2 218.42 1652.0 74.3 221.63 1872.03 74.4 224.86 2095.28 74.5 228.10 2321.76 74.56 (FSL) 230.13 2459.23 74.6 231.50 2551.56 74.7 233.67 2784.18 74.8 235.63 3018.84 74.9 237.51 3255.41 75.0 239.21 3493.79 75.1 240.67 3733.75 75.2 241.97 3975.08 75.3 243.17 4217.65 75.4 244.29 4461.39 75.5 245.35 4706.21 ----- Denotes cross section referred to in Figure 5 and Figure 9.
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Description of map
Yellow contour represent maximum fill of 74.56m AHD
Green contour represents alternative filling regime of 74.00m AHD.
Blue Line represents nominal contour for low level establishment fill of 73.5m AHD.
.
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Appendix B: 2013 EVC mapping
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Appendix C: Flora and fauna species list Sources: Ho et al. 2006; SKM, 2001; DSE, 2005b; DSE, 2013; SKM, 2010, Rakali, 2013; Biosis, 2013; DEPI, 2013 Common Name Scientific Name Last record Source Fauna - Birds DEPI, 2013, 2013 ; BirdLife Australia, 2013 ; Australasian Darter Anhinga novaehollandiae 2013 Ho et al. 2006; Biosis, 2013 Australian Magpie Cracticus tibicen 2013 BirdLife Australia, 2013 ; Biosis, 2013 DEPI, 2013, 2013 ; BirdLife Australia, 2013 ; Australian Pelican Pelecanus conspicillatus 2013 Ho et al. 2006; Biosis, 2013 Australian Reed -Warbler Acrocephalus stentoreus 2013 BirdLife Australia, 2013 ; Biosis, 2013 DEPI, 2013 ; BirdLife Australia, 2013 ; Ho et Australian Shelduck Tadorna tadornoides 2013 al. 2006; Biosis, 2013 DEPI, 2013 ; BirdLife Australia, 2013 ; Ho et Australian White Ibis Threskiornis molucca 2013 al. 2006; Biosis, 2013 Australian Wood Duck Chenonetta jubata 2006 DEPI, 2013 ; Ho et al. 2006 Black Kite Milvus migrans 2013 BirdLife Australia, 2013 ; Biosis, 2013 DEPI, 2013 ; BirdLife Australia, 2013 ; Ho et Black Swan Cygnus atratus 2013 al. 2006; Biosis, 2013 Black -faced Cuckoo -Shrike Coracina novaehollandiae 2013 Biosis, 2013 Black -shouldered Kite Elanus axillaris 2013 Biosis, 2013 BirdLife Australia, 2013 ; Ho et al. 2006; Black-tailed Native-hen Gallinula ventralis 2013 Biosis, 2013 Brown Treecreeper Climacteris picumnus 2013 BirdLife Australia, 2013 ; Biosis, 2013 Caspian Tern Hydroprogne caspia 1998 BirdLife Australia, 2013 Common Starling Sturnus vulgaris 2013 BirdLife Australia, 2013 ; Biosis, 2013 Crested Pigeon Ocyphaps lophotes 2013 BirdLife Australia, 2013 ; Biosis, 2014 Dusky Moorhen Gallinula tenebrosa 1988 DEPI, 2013 ; Clunie, 2010 Dusky Woodswallow Artamus cyanopterus 2013 Biosis, 2013 BirdLife Australia, 2013 ; SKM, 2010; Biosis, Eastern Great Egret Ardea modesta 2013 2013 Eastern Rosella Platycercus eximius 2013 BirdLife Australia, 2013 ; Biosis, 2013 BirdLife Australia, 2013 ; Ho et al. 2006; Eurasian Coot Fulica atra 2013 Biosis, 2013 Galah Eolophus roseicapillus 2013 BirdLife Australia, 2013 ; Biosis, 2013 DEPI, 2013 ; BirdLife Australia, 2013 ; Ho et Great Cormarant Phalacrocorax carbo 2013 al. 2006; Biosis, 2013 Grey Shrike -thrush Colluricincla harmonica 2013 Biosis, 2013 DEPI, 2013 ; BirdLife Australia, 2013 ; Biosis, Grey Teal Anas gracilis 2013 2013 Hardhead Aythya australis 2006 Ho et al. 2006 House Sparrow Passer domesticus 2013 Biosis, 2013 Laughing Kookaburra Dacelo novaeguineae 2013 Biosis, 2013 DEPI, 2013 ; BirdLife Australia, 2013 ; Ho et Little Black Cormorant Phalacrocorax sulcirostris 2013 al. 2006; Biosis, 2013 Long -billed Corella Cacatua tenuirostris 2013 Biosis, 2013 Magpie -lark Grallina cyanoleuca 2013 BirdLife Australia, 2013 ; Biosis, 2013 Musk Duck Biziura lobata 2006 Ho et al. 2006 Nankeen Night Heron Nycticorax caledonicus 2013 Biosis, 2013 Noisy Miner Manorina melanocephala 2013 BirdLife Australia, 2013 ; Biosis, 2013 DEPI, 2013 ; BirdLife Australia, 2013 ; Ho et Pacific Black Duck Anas superciliosa 2013 al. 2006; Biosis, 2013 Pied Cormorant Phalacrocorax varius 2013 DEPI, 2013 ; Rakali 2013; Biosis, 2013 DEPI, 2013 ; BirdLife Australia, 2013 ; Ho et Purple Swamphen Porphyrio porphyrio 2013 al. 2006; Biosis, 2013 Red -rumped Parrot Psephotus haematonotus 2013 BirdLife Australia, 2013 ; Biosis, 2013 Restless Flycatcher Myiagra inquieta 2013 Biosis, 2013 Rock Dove Columba livia 2013 Biosis, 2013 Royal Spoonbill Platalea regia 2013 Ho et al. 2006; Rakali 2013; Biosis, 2013 Sacred Kingfisher Todiramphus sanctus 2013 BirdLife Australia, 2013 ; Biosis, 2013 Splendid Fairy -wren Malurus splendens 2013 BirdLife Australia, 2013 ; Biosis, 2014 Spotless Crake Porzana tabuensis 2013 Rakali 2013 DEPI, 2013 ; BirdLife Australia, 2013 ; Ho et Straw-necked Ibis Threskiornis spinicollis 2013 al. 2006; Biosis, 2013 Striated Pardalote Pardalotus striatus 2013 BirdLife Australia, 2013 ; Biosis, 2013 Superb Fairy -wren Malurus cyaneus 2013 BirdLife Australia, 2013 ; Biosis, 2014
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Common Name Scientific Name Last record Source Swamp Harrier Circus approximans 2006 DEPI, 2013 ; Ho et al. 2006 Tree Martin Petrochelidon nigricans 2013 BirdLife Australia, 2013 ; Biosis, 2013 Wedge -tailed Eagle Aquila audax 2013 BirdLife Australia, 2013 ; Biosis, 2014 Welcome Swallow Hirundo neoxena 2013 BirdLife Australia, 2013 ; Biosis, 2015 Whistling Kite Haliastur sphenurus 2013 BirdLife Australia, 2013 ; Biosis, 2015 BirdLife Australia, 2013 ; Rakali 2013; Biosis, White-bellied Sea-Eagle Haliaeetus leucogaster 2013 2013 White -browed Woodswallow Artamus superciliosus 2013 Biosis, 2013 White -necked Heron Ardea pacifica 2013 BirdLife Australia, 2013 ; Biosis, 2015 White -plumed Honeyeater Lichenostomus penicillatus 2013 BirdLife Australia, 2013 ; Biosis, 2015 Willie Wagtail Rhipidura leucophrys 2013 BirdLife Australia, 2013 ; Biosis, 2016 Yellow Spoonbill Platalea flavipes 1991 Clunie, 2010 Australasian Grebe Tachybaptus novaehollandiae 2011 BirdLife Australia, 2013 Australian Raven Corvus coronoides 2005 BirdLife Australia, 2013 Black -winged Stilt Himantopus himantopus 2011 BirdLife Australia, 2013 Brown Falcon Falco berigora 2005 BirdLife Australia, 2013 Fairy Martin Petrochelidon ariel 1998 DEPI, 2013 Little Grassbird Megalurus gramineus 2001 DEPI, 2013 Little Pied Cormorant Microcarbo melanoleucos 2005 DEPI, 2013 ; BirdLife Australia, 2013 Little Raven Corvus mellori 2011 BirdLife Australia, 2013 Masked Lapwing Vanellus miles 2011 BirdLife Australia, 2013 Plumed Whistling -Duck Dendrocygna eytoni 1998 DEPI, 2013 Red -capped Robin Petroica goodenovii 2011 BirdLife Australia, 2013 White -faced Heron Egretta novaehollandiae 2011 BirdLife Australia, 2013 Zebra Finch Taeniopygia guttata 2005 BirdLife Australia, 2013 Silver Gull Chroicocephalus novaehollandiae 1998 DEPI, 2013 Fauna - Fish Australian Smelt Retropinna semoni 2013 Ho et al. 2006; Biosis, 2013 Bony Bream Nematalosa erebi 2013 DEPI, 2013 ; Ho et al. 2006; Biosis, 2013 Carp Gudgeon Hypseleotris compressa 2013 Ho et al. 2006; Biosis, 2013 Common (European) Carp+ Cyprinus carpio 2013 DEPI, 2013 ; Ho et al. 2006; Biosis, 2013 Flathead Gudgeon Philypnodon grandiceps 2013 Ho et al. 2006; Biosis, 2013 Flat -headed Galaxias Galaxias rostratus 1963 DEPI, 2013 Craterocephalus stercusmuscarum Unspecked Harydhead 2013 SKM 2010; Ho et al. 2006; Biosis, 2013 fulvus Freshwater Catfish Tandanus tandanus 1981 DEPI, 2013 ; SKM, 2010 Gambusia+ Gambusia holbrooki 2013 Ho et al. 2006; Biosis, 2013 DEPI, 2013 ; KM, 2010; Ho et al. 2006; Golden Perch Macquaria ambigua 2013 Biosis, 2013 Goldfish+ Carassius auratus 2013 DEPI, 2013 ; Biosis, 2013 Murray Cod Maccullochella peelii 2006 DEPI, 2013 ; SKM, 2010; Ho et al. 2006 Biosis, 2013 (Identified in neighbouring Murray Hardyhead^ Craterocephalus fluviatilis N/A Middle Reedy) Oriental Weatherloach+ Misgurnus anguillicaudatus 2013 Biosis, 2013 Redfin Perch+ Perca fluviatilis 2006 DEPI, 2013 ; Ho et al. 2006 Silver Perch Bidyanus bidyanus 1981 DEPI, 2013 ; SKM, 2010 Tench+ Tinca t inca 1981 DEPI, 2013 Fauna - Other Barking Marsh Frog Limnodynastes fletcheri 2013 Ho et al. 2006; Biosis, 2013 Boulenger's Skink Morethia boulengeri 2013 Biosis, 2013 Common Long -necked Turtle Chelodina longicollis 2013 Ho et al. 2006; Biosis, 2013 European Rabbit+ Oryctolagus cinuculus 2013 Rakali, 2013 Legless Lizard - species unknown N/A 2013 Biosis, 2013 Murray River Turtle Emydura macquarii 20 06 SKM, 2010; Ho et al. 2006 Peron's Tree Frog Litoria peroni 2013 Ho et al. 2006; Biosis, 2013 Red Fox+ Vulpes vulpes 2013 Rakali, 2013 Spotted Marsh Frog Limnodynastes tasmaniensis 2013 Ho et al. 2006; Biosis, 2013 Swamp Wallaby Wallabia bicolor 2013 Rakali, 2013 Tiger Snake Notechis scutatus 2013 Rakail, 2013 Water Rat Hydromys chrysogaster 1988 DEPI, 2013 ; Rakali, 2013 White -striped Freetail Bat Tadarida australis 2013 Biosis, 2013
Macroinverbrates Ancylidae - 2013 Ho et al. 2006; Biosis, 2013
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Common Name Scientific Name Last record Source Atyidae - 2013 Ho et al. 2006; Biosis, 2013 Baetidae - 2013 Ho et al. 2006; Biosis, 2013 Caenidae - 2013 Biosis, 2013 Ceratopogonidae - 2006 Ho et al. 2006 Chironominae - 2013 Ho et al. 2006; Biosis, 2013 Coenagrionidae - 2013 Biosis, 2013 Corixidae - 2013 Ho et al. 2006; Biosis, 2013 Ecnomidae - 2013 Biosis, 2013 Glossiphoniidae - 2013 Biosis, 2013 Hydrophilidae - 2013 Ho et al. 2006; Biosis, 2013 Hydroptilidae - 2006 Ho et al. 2006 Mesoveliidae - 2006 Ho et al. 2006 Notonectidae - 2013 Biosis, 2013 Oligochaeta - 2013 Biosis, 2013 Orthocladiinae - 2013 Biosis, 2013 Palaemonidae - 2013 Ho et al. 2006; Biosis, 2013 Paramelitidae - 2006 Ho et al. 2006 Parastacidae - 2013 Ho et al. 2006; Biosis, 2013 Physidae - 2006 Ho et al. 2006 Planorbidae - 2006 Ho et al. 2006 Sciomyzidae - 2006 Ho et al. 2006 Flora - native Austral Mudwort Limosella australis 2013 Rakali 2013 Australian Salt -grass Distichlis distichophylla 2013 Rakali 2013 Billabong Rush Juncus usitatus 2013 Rakali 2013 Tecticornia pergranulata subsp. Blackseed Glasswort 2013 Rakali 2013 pergranulata Senecio cunninghamii var. Branching Groundsel 2013 Rakali 2013 cunninghamii Bristly Wallaby -grass Rytidosperma setaceum 2013 Rakali 2013 Broad -leaf Cumbungi Typha orientalis 2013 Rakali 2013 Brown Beetle -grass Leptochloa fusca subsp. fusca unknown DEPI, 2013 , SKM 2010 Ludwigia peploides subsp. Clove-strip 2013 Rakali 2013 montevidensis Coarse Water -milfoil Myriophyllum caput -medusae 2013 Rakali 2013 Common Blown -grass Lachnagrostis filiformis s.s. 2013 Rakali 2013 Common Nardoo Marsilea drummondii 2013 Rakali 2013 Common Reed Phragmites australis 2013 Rakali 2013 Common Spike -sedge Eleocharis acuta 2013 Rakali 2013 Common Swamp Wallaby -grass Amphibromus nervosus 2013 Rakali 2013 Cotton Fireweed Senecio quadridentatus 2013 Rakali 2013 Cumbungi Typha spp. 2006 Ho et al. 2006 Dark Roly -poly Sclerolaena muricata var. semiglabra 2013 Rakali 2013 Flat -top Saltbush Atriplex lindleyi subsp. lindleyi 2013 Rakali 2013 Giant Rush Juncus ingens 2013 Ho et al. 2006 and Rakali 2013 Glaucous Goosefoot Chenopodium glaucum 2013 Rakali 2013 Gold Rush Juncus flavidus 2013 Rakali 2013 Grass Bindweed Convolvulus remotus 2013 Rakali 2013 Jersey Cudweed Pseudognaphalium luteoalbum 2013 Rakali 2013 Lesser Joyweed Alternanthera denticulata s.l. 2013 Rakali 2013 Mallee Love -grass Eragrostis dielsii 2013 Rakali 2013 Native Sow -thistle Sonchus hydrophilus 2013 Rakali 2013 Nitre Goosefoot Chenopodium nitrariaceum 2013 Rakali 2013 Nitre -bush Nitraria billardierei 2013 Rakali 2013 Nodding Saltbush Einadia nutans subsp. nutans 2013 Rakali 2013 Pacific Azolla Azolla filiculoides 2013 Rakali 2013 Poong'ort Carex tereticaulis 2013 Rakali 2013 Prickly Saltwort Salsola tragus subsp. tragus 2013 Rakali 2013 Rat -tail Couch Sporobolus mitchellii 2013 Rakali 2013 River Club Rush Schoenoplectus validus 2006 Ho et al. 2006 River Club -sedge Schoenoplectus tabernaemontani 2013 Rakali 2013 River Red -gum Eucalyptus camaldulensis 2013 Rakali 2013
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Common Name Scientific Name Last record Source Robust Water -milfoil Myriophyllum papillosum 2013 Rakali 2013 Rosinweed Cressa australis 2013 Rakali 2013 Rough Spear -grass Austrostipa scabra 2013 Rakali 2013 Ruby Saltbush Enchylaena tomentosa var. tomentosa 2013 Rakali 2013 Shining Pennywort Hydrocotyle sibthorpioides 2013 Rakali 2013 Short Water -starwort Callitriche brachycarpa 2013 Rakali 2013 Short -leaf Bluebush Maireana brevifolia 2013 Rakali 2013 Slender Carpet -weed Glinus oppositifolius 2013 Rakali 2013 Slender Knotweed Persicaria decipiens 2013 Rakali 2013 Small Loosestrife Lythrum hyssopifolia 2013 Rakali 2013 Southern Cane -grass Eragrostis infecunda 2013 Rakali 2013 Spiny Flat -sedge Cyperus gymnocaulos 2013 Rakali 2013 Spiny Lignum Duma horrida subsp. horrida 2013 Rakali 2013 Swamp Crassula Crassula helmsii 2013 Rakali 2013 Tall Fireweed Senecio runcinifolius 2013 Rakali 2013 Tangled Lignum Duma florulenta 2013 SKM 2001 and Rakali 2013 Tassel Sedge Carex fascicularis 2013 Rakali 2013 Twin -leaf Bedstraw Asperula gemella 1996 DEPI, 2013 ; SKM, 2010 Water Milfoil Myriophyllum spp. 2013 Ho et al. 2006 and Rakali 2013 Water Pepper Persicaria hydropiper 2013 Rakali 2013 Waterwort Elatine gratioloides 2013 Rakali 2013 Windmill Grass Chloris truncata 2013 Rakali 2013 Woolly New Holland Daisy Vittadinia gracilis 2013 Rakali 2013 Sprawling Saltbush* Atriplex suberecta 2013 Rakali 2013 Tah -vine* Boerhavia dominii 2013 Rakali 2013 Flat Spurge* Chamaesyce drummondii 2013 Rakali 2013 Clammy Goosefoot* Chenopodium pumilio 2013 Rakali 2013 Variable Flat -sedge* Cyperus difformis 2013 Rakali 2013 Common Boobialla* Myoporum insulare 2013 Rakali 2013 Hedge Saltbush* Rhagodia spinescens 2013 Rakali 2013 *Taxon which is both indigenous and naturalised but has extended beyond its known or suspected geographical distribution Flora - exotic African Box -thorn Lycium ferocissimum 2013 Rakali 2013 Annual Beard -grass Polypogon monspeliensis 2013 Rakali 2013 Aster -weed Aster subulatus 2013 Rakali 2013 Bathurst Burr Xanthium spinosum 2013 Rakali 2013 Black Nightshade Solanum nigrum s.l. 2013 Rakali 2013 Buck's -horn Plantain Plantago coronopus 2013 Rakali 2013 Celery Buttercup Ranunculus sceleratus subsp. sceleratus 2013 Rakali 2013 Coast Barb -grass Parapholis incurva 2013 Rakali 2013 Common Ice -plant Mesembryanthemum crystallinum 2013 Rakali 2013 Common Peppercress Lepidium africanum 2013 Rakali 2013 Couch Cynodon dactylon var. dactylon 2013 Rakali 2013 Creeping Heliotrope Heliotropium supinum 2013 Rakali 2013 Curled Dock Rumex crispus 2013 Rakali 2013 Desert Ash Fraxinus angustifolia 2013 Rakali 2013 Drain Flat -sedge Cyperus eragrostis 2013 Rakali 2013 Flaxleaf Fleabane Conyza bonariensis 2013 Rakali 2013 Fog -fruit Phyla canescens 2013 Rakali 2013 Great Brome Bromus diandrus 2013 Rakali 2013 Leontodon taraxacoides subsp. Hairy Hawkbit 2013 Rakali 2013 taraxacoides Hastate Orache Atriplex prostrata 2013 Rakali 2013 Horehound Marrubium vulgare 2013 Rakali 2013 Jointed Rush Juncus articulatus subsp. articulatus 2013 Rakali 2013 Marsh Yellow -cress Rorippa palustris 2013 Rakali 2013 Onion Weed Asphodelus fistulosus 2013 Rakali 2013 Ox -tongue Helminthotheca echioides 2013 Rakali 2013 Paspalum Paspalum dilatatum 2013 Rakali 2013 Paterson's Curse Echium plantagineum 2013 Rakali 2013 Prairie Grass Bromus catharticus 2013 Rakali 2013 Prickly Lettuce Lactuca serriola 2013 Rakali 2013 Prostrate Knotweed Polygonum aviculare s.l. 2013 Rakali 2013 Pyramid Tree Lagunaria patersonia subsp. patersonia 2013 Rakali 2013 Ribwort Plantago lanceolata 2013 Rakali 2013
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Common Name Scientific Name Last record Source Rough Sow -thistle Sonchus asper s.s. 2013 Rakali 2013 Sea Barley -grass Hordeum marinum 2013 Rakali 2013 False Daisy Eclipta postrata 2013 Rakali 2013 Small -flower Mallow Malva parviflora 2013 Rakali 2013 Sowbane Chenopodium murale 2013 Rakali 2013 Spear Thistle Cirsium vulgare 2013 Rakali 2013 Spiny Rush Juncus acutus subsp. acutus 2013 Rakali 2013 Strawberry Clover Trifolium fragiferum var. fragiferum 2013 Rakali 2013 Tamarisk Tamarix spp. 2013 Rakali 2013 Variegated Thistle Silybum marianum 2013 Rakali 2013 Water Couch Paspalum distichum 2013 Rakali 2013 Weeping Willow Salix babylonica s.l. 2013 Rakali 2013 Willow -leaf Lettuce Lactuca saligna 2013 Rakali 2013
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Appendix D: Water requirements of ecological values Table D1: Ecological values supported at Third Reedy Lake Example (*denotes threatened) Requirements Values Listed species General species Feeding Habitat Breeding Waterbird feeding guilds Prefer permanent Eastern Great Egret, Australasian water however Intermediate Egret, Darter, Little shoreline can Pied Cormorant: Black Cormorant, recede. Fish , Generally stimulated by Caspian Tern, White-faced crustaceans, flood and season (Sept- Eastern Great Heron, Little Pied reptiles, small Prefer permanent May) for ~ 12 months Egret, Pied Cormorant, mammals, aquatic water body. Caspian Tern: Fish eating Cormorant, Australian insects. Generally trees, stimulated by flood and waterbirds White-bellied Pelican, Great shrubs (i.e. lignum) season (Sept-Feb). Sea Eagle, Cormorant, Nankeen Night and reeds. Nankeen Night Heron: Nankeen Sacred Kingfisher, Heron will feed at breed throughout year Night Heron White-necked night in shallow pending food Heron, water on a wide availability, breeds in Australasian variety of insects, colonies with egrets Grebe crustaceans, fish and cormorants and amphibians. Roost in trees in wetlands. Nest over Straw-necked Ibis, thick emergent Generally stimulated by Australian White Royal Prefer shallow with vegetation i.e. flood and season (Oct- Waders Ibis, Yellow Spoonbill short vegetation rushes, reeds or May) for up to >5 to 12 Spoonbill, Black- lignum. Will months winged Stilt abandon nest upon fast recession. Grey Teal, Australian Shelduck, Australian Wood Ducks Generally Musk Duck : Stimulated Duck, Black-tailed including: opportunistic but by flood and season Native Hen, Dusky dabbling prefer deep and (June-Dec) for 6-8 Moorhen, Pacific Algae, grasses, ducks/ grazing permanent water. months. Musk Duck, Black Duck, seeds, herbs, waterfowl/ Trees, reeds, Hardhead Purple aquatic plants, shoreline shrubs, grasses. Hardhead: stimulated Swamphen, Black insects, shoots foragers/ Nest in densely by flood and season Swan, Eurasian deep water vegetated areas (August- December) for Coot, Hardhead, foragers near open water 5- 8 months. Spotless Crake, Masked Lapwing, Plumed Whistling Duck Nest in trees or Nest is a large flimsy Brown open remanent platform of twigs and Other N/A Insects and larvae Treecreeper woodland sticks, lined with green vegetation leaves. Fish guilds Small aquatic Unspecked invertebrates, Hardyhead, Smelt, Bony Water temperature and zooplankton, Wetland Murray Bream, Carp Slow-flowing or still in some cases rising detritus, opportunists Hardyhead^, Gudgeon, Flat water flows cues spawning microorganisms, Unspecked Head Gudgeon (broadly Sept-April) crustaceans, Hardyhead aquatic vegetation Murray Cod, crustaceans, Main channel Slow flowing Water temperature and Freshwater N/A insects, fish and specialists riverine with woody day length cues Catfish frogs
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Example (*denotes threatened) Requirements Values Listed species General species Feeding Habitat Breeding debris (Catfish with spawning (broadly mud/sand/gravel) Sept-Dec)
Slow flowing turbid Aquatic insects, Rise of water level and water with littoral Flood Silver Perch, crustaceans, temperature cues N/A veg and woody spawners Golden Perch aquatic plant spawning (broadly Oct- debris (also deep material Jan) for Golden Perch) Reptiles Murray River Aquatic vegetation, In spring and summer Turtle, Required Turtles N/A macro inverts and lay eggs in burrow close Eastern Long- permanent water carrion to water necked Turtle Mix, some prefer open water (i.e. Generally somewhere Peron’s Tree frog) Spotted Grass between spring and other prefer Frog, Peron's Tree Insects, aquatic autumn after heavy Frogs N/A abundant emergent Frog, Barking vegetation rains. Lay eggs in slow veg (Barking Marsh Marsh Frog moving/ still water or frog), others are terrestrial habitat generalists (Spotted Marsh frog) Example (*denotes threatened) Requirement General EVC Ecological service Listed species characteristic/ Frequency Duration species Dominate flora EVCs reeds, rushes, sedges Annual or near Filters water, adds (Cumbungi, River- Tall Marsh Branching annual inundation biological activity, Club rush), some 1 to 8 months (EVC 821) Groundsel (8-10 years in every habitat, refuge, nesting giant rush, 10) for waterbirds common weed mainly Tangled lignum Twin-leaf Inundated less than >1 month to >1 and salt bush Bedstraw, 3 in 10 years year mainly Intermittent Short Water- 3 to 6 months for Swampy starwort, Flood every 3 to 7 Red Gum woodlands. Natural Woodland Spiny Lignum, years timing preferable (EVC 813) Dark Roly- Duration of 2 to 4 poly, Flat-top Flood every 2 to 4 Black Box months spring- Saltbush years summer flooding Lignum Generally tangled Inundate 3-7 years 1 month to >1 year Swamp (EVC N/A lignum, Clove Key waterbird habitat in every 10 years before drying 104) Strip etc (i.e. hollows, fallen Lignum branches and shade) Swampy Tangled Lignum, Inundate 3-7 years >1 month to >1 and provides seed for N/A Woodland Black Box etc in every 10 years year before drying recruitment (EVC 823) Black Box, Riverine Tangled Lignum, Inundate less than 3 Chenopod 1 month to >1 year N/A Spiny Lignum, years in every 10 Woodland before drying Common Reed years (EVC 103) etc Semi-arid Chenopod Nitre-bush, Prickly N/A No flooding required Woodland Saltwort etc (EVC 98)
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Example (*denotes threatened) Requirements Values Listed species General species Feeding Habitat Breeding Annual or near Filters water, adds Aquatic rushes, sedges, annual inundation biological activity, Herbland (EVC N/A aquatic herbs 1 to 8 months (8-10 years in every habitat, refuge, nesting 653) mainly 10) for waterbirds Open water Supports long term fish Open water devoid of aquatic populations and deep with dead N/A vegetation with Permanent inundation water foragers. Dead timber dead river Red river red gums provide Gums habitat for waterbirds ^ No records of species in Third Reedy Lake but present at neighbouring Middle Reedy and therefore should be considered. Source: Biosis, 2013; Rakali, 2013; DSE, 2012a; DSE, 2012b; Rogers & Ralph, 2011; Roberts & Marston, 2011; Barker et al. 1995.
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Appendix E: Water regime summaries Table C3: Recommended watering for Third Reedy Lake Third Reedy Lake: recommended watering regime Year Establishment regime (2-3 cycles) Long term regime • Fill to FSL 74.56m AHD and maintain inundation at Black Box zone for minimum of 2 months 1 • Allow to recede with inundation of River Red Gum zone not exceeding four months • Lignum and sedges can tolerate up to 7 months of inundation • Likely to maintain water for maximum of 9 months • Follow up flooding to maximum to around 74.2- 2 73.5mAHD (preferably 20-30 cm depth) to recharge • Remain dry soil moisture for Red Gum seedling lasting from 4-6 weeks 3 • Remain dry
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