Fish and Flows. Adaptive environmental water use for fish and fish habitats in NSW.

Transcription

1 Fish and Flows Adaptive environmental water use for fish and fish habitats in NSW JUNE

2 Title: Fish and Flows: Adaptive environmental water use for fish and fish habitats in NSW ( ) State of NSW through Department of Primary Industries Fisheries NSW 2014 This report is copyright. You may download, display, print and reproduce this material in an unaltered form only (retaining this notice) for your personal use or for non-commercial use within your organisation. To copy, adapt, publish, distribute or commercialise any of this report you will need to seek permission from the Department of Trade and Investment, Regional Infrastructure and Services. Disclaimer Information contained in this report is based on knowledge and understanding at the time of writing (April 2014). However, because of advances in knowledge, users are reminded of the need to ensure that information on which they rely is up to date and to check the currency of the information with the appropriate officer of the NSW Department of Primary Industries or the user s independent advisor. This report should be cited as: NSW Department of Primary Industries (2014) Fish and Flows: Adaptive environmental water use for fish and fish habitats in NSW ( ), NSW Department of Primary Industries (Fisheries NSW), Armidale.

3 Table of contents Executive Summary... 1 Border Rivers... 3 The Border Rivers Catchment... 3 Fish Condition... 4 Environmental Water Allocations /2013 Watering Summary... 5 Fish-specific watering actions... 7 Outcomes... 8 Future Priorities... 8 Gwydir The Gwydir Catchment Fish Condition Environmental Water Allocations /2013 Watering Summary Fish-specific watering actions Outcomes Future Priorities The Namoi The Namoi Catchment Fish Condition Environmental Water Allocations /2013 Watering Summary Fish-specific Watering Actions Outcomes Future Priorities Macquarie The Macquarie Catchment Fish Condition Environmental Water Allocations /2013 Watering Summary Fish-specific watering actions Outcomes Future Priorities Lachlan The Lachlan Catchment Fish Condition Environmental Water Allocations /2013 Watering Summary Fish-specific watering actions Outcomes Future Priorities i

4 Murrumbidgee The Murrumbidgee Catchment Fish Condition Environmental Water Allocations /2013 Watering Summary Fish-specific watering actions Outcomes Future Priorities Edward-Wakool The Edward-Wakool System Fish Condition Environmental Water Allocations /2013 Watering Summary Fish-specific watering actions Outcomes Future Priorities Murray/Lower Darling The Murray/Lower Darling system Fish Condition Environmental Water Allocations /2013 Watering Summary Fish-specific watering actions Outcomes Future Priorities Tables Table 1 - Summary of environmental water holdings Border Rivers catchment... 5 Table 2 - Summary of environmental water holdings Namoi Valley Table 3- Summary of environmental water holdings Namoi Valley Table 4 - Summary of environmental water holdings (total registered entitlement) Macquarie Valley Table 5 - Summary of environmental water holdings Lachlan Valley Table 6 - Summary of environmental water holdings Murrumbidgee Valley Table 7 Summary of environmental water holdings Murray Valley (NSW component) Table 8 - Summary of environmental watering events in the Edward-Wakool (2012/2013) 42 Table 9 - Summary of environmental water holdings Murray Valley (NSW share) Table 10 : List of Murray Darling Valleys wetlands watered during the season with NSW AEW and/or CEWO allocations (source NSW OEH) ii

5 Figures Figure 1 The Border Rivers Catchment... 3 Figure 2: 2011/2012 Rainfall deciles for NSW... 4 Figure 3 Pindari stimulus flow proposed release: discharge from Pindari Dam and expected discharge at Mungindi... 5 Figure 4 Severn River (Ashford) and Barwon River (Mungindi) 1st December to 15 th December Figure 5 Temperature and flow data from Pindari stimulus release... 7 Figure 6 Seasonal and temperature breeding thresholds Namoi River... 8 Figure 7 Temperature and discharge at Mungindi (Barwon River)... 9 Figure 8 - The Gwydir Catchment Figure /2013 River height and discharge data for the Gwydir River (Pallamallawa) 11 Figure 10 The Namoi Catchment system Figure 11- Modelled monthly mean flows for the Namoi River at Bugilbone Figure 12 Current arrangements versuss modelled pre-development flow duration curve for the Namoi River (at Wee Waa) Figure 13 Comparison of Namoi River flows (at Narrabri) with and without CEWH allocations Figure 14 - The Macquarie Catchment Figure /2013 flow conditions in the Macquarie River (Warren Town weir) Figure 16 Macquarie River environmental water delivery ) Figure 17 Macquarie River discharge and temperature at Dubbo (August December 2012) Figure 18 - The Lachlan Catchment) Figure flow conditions in the Lachlan River (Willandra weir) Figure environmental flow in the Lower Lachlan (Hillston Weir) Figure 21 - The Murrumbidgee catchment) Figure 22 - Murrumbidgee River height and flow data (Darlington Point) Oct-Nov Figure 23 - Murrumbidgee River height and flow data (Darlington Point) Oct-Nov Figure 24 - The Edward-Wakool system Figure 25 - Yallakool Creek height and flow data (Yallakool Regulator) Oct Apr Figure 26 - Colligen Creek height and flow data (Colligen regulator) Oct Apr Figure 27 The Murray/Lower Darling system) Figure 28 The Murray Wentworth watering year) iii

6 Executive Summary Alterations to the natural flow regime within every major valley of the Murray- Darling Basin have had significant impacts on the abundance and diversity of native fish populations. Reductions in overall discharge, changes to the seasonality of flow, the reduced frequency and magnitude of unregulated events and the suppression of water temperatures through cold water discharges have all combined to threaten a range of ecological processes which drive native fish production. Successive New South Wales (NSW) and Commonwealth Governments have sought to address these threats through the equitable allocation of water between the environment and consumptive users. A key component of this response has been the development of environmental water portfolios held by both the NSW and Commonwealth Governments. The volume of adaptive or held environmental water within NSW has increased significantly in recent years. State-based programs such as Riverbank and the NSW Wetland Recovery Program, combined with the Commonwealth s Living Murray Initiative and purchases as part of the Basin Plan have all made a significant contribution to the quantum of water available for environmental use. With this increased availability of resources comes an increased responsibility of agencies, stakeholder groups and communities to deliver the best possible outcomes from the available water across the widest possible range of environmental parameters. This document outlines the current status of adaptive environmental water holdings in NSW for each major valley and the associated consideration in planning and decision making given to fish and fish habitats. Fisheries NSW is represented on all of the environmental water advisory groups within NSW, however the development of flow-related actions to support native fish abundance and diversity varies considerably across the Basin. The acknowledgment of the specific flow-related needs of native fish and associated habitats within environmental water planning is a major step forward for the conservation of our inland fisheries resources. As the frameworks surrounding the planning and delivery of environmental water continue to mature, a number of important issues relevant to native fish warrant further consideration. These include: Utilising environmental water in conjunction with unregulated events The input of carbon and nutrients from unregulated events creates significant increases in riverine metabolism and productivity. Many of these responses may not be replicated through the delivery of regulated environmental water alone. The development of environmental watering plans that seek to maximise the benefit from unregulated events will assist in the conservation of native fish populations. 1

7 Aligning life-history requirements of native fish to the delivery of environmental water Increased flow does not always benefit native fish. The sustained higher discharges in many regulated valleys during Spring/Summer may in fact hinder the recruitment of native fish in many circumstances. Identifying specific features of the hydrograph that support the life history requirements of individual species and guilds of fish (groups of species with similar life history) and delivering water accordingly will lead to improved outcomes for native fish. Increasing our understanding of habitat/flow interactions Habitat availability within rivers is a function of flow. With a finite amount of water available to the environment, understanding the relationship between flow and critical habitat features such as large woody debris, benches and anabranch systems will allow managers to maximise the benefits of environmental water delivery. Developing long-term objectives to support a full range of species No single flow regime will provide benefits to all native fish species. To periodically meet the requirements of all species within a population, interannual variation of priorities and delivery strategies is essential. Consideration must be given to the recruitment strategies, life expectancy and resilience of current populations to develop watering plans that have a timeframe of ten or more years. Like all long-term planning, the annual objectives will have to respond to antecedent conditions, however a strategic understanding of the native fish outcomes being sought over longer time periods is essential. 2

8 Border Rivers The Border Rivers Catchment The Border Rivers catchment falls across both southern Queensland and northern NSW. The Macintyre and Dumaresq Rivers are the major tributaries which join upstream of Boggabilla, continuing in a westerly direction as the Macintyre. The upper reaches of the Macintyre River within NSW drain in a north-westerly direction with the Pindari Dam regulating its major tributary, the Severn River (NSW). The Dumaresq River drains the north-eastern part of the catchment within Queensland, being formed by the junction of the Severn River (QLD) and Tenterfield Creek. The Mole and Beardy Rivers and Ottley Creek all make unregulated tributary contributions. The Glenlyon Dam on the Dumaresq provides the major regulating capacity within the Border Rivers catchment. The geomorphology changes significantly below Goondiwindi, with a low-energy meandering anabranch system becoming the dominant feature. Prior to the Macintyre reaching the township of Mungindi, it is joined by the Weir River from Queensland and becomes the Barwon River. Figure 1 The Border Rivers Catchment (Source CEWO) The Border Rivers catchment experienced drier conditions in the watering year compared to two very wet years prior (see Figure 2). Unregulated events in January and March from the Dumaresq system and January in the Macintyre/Severn (NSW) were the major inflows into the system. 3

9 Figure 2: 2011/2012 Rainfall deciles for NSW (Source BoM) Fish Condition The Sustainable Rivers Audit provides an overall fish condition rating for the Border Rivers catchment as Moderate. It was one of only two regulated valleys in the Basin to achieve this ranking. Individual regions within the catchment ranged from Poor (Lowland and Montane) to Good (Upland), with the Upland zone returning the 3 rd highest ranking of all zones in the Basin. The dominance of native species decreased as elevation reduced, with carp becoming particularly prevalent in the lowland regions. An analysis of catch data from the NSW Freshwater Fish Database by Gilligan (Fisheries NSW; unpublished data) identified the Macintyre sub-catchment as having one of the most diverse native fish populations within the NSW area of the Basin. Additional research funded through the Recreational Fishing Trust has demonstrated little difference in the structure of the fish community between the Macintyre and Dumaresq sub-catchments, however there is significant variability in fish communities between individual sites. Researchers are currently investigating the potential impact of stocking on the growth and recruitment of native species within the Border Rivers catchment. 4

10 Environmental Water Allocations Surface water flows within the Border Rivers catchment are managed through Water Sharing Plan for the NSW Border Rivers Regulated River Water Source (WSP). The WSP identifies rules to manage planned environmental water through the provision of a continuous flow rule from Pindari, varying translucency arrangements depending on the time of year and the allocation of a stimulus flow of up to 4,000ML when inflows into Pindari exceed 1,200 ML on any single day between April and August. Both the translucency and stimulus flows are only protected downstream of Pindari to the next point of significant inflow, being Frazers Creek near Ashford. The Commonwealth hold a small entitlement of adaptive environmental water in NSW (see Table 1 below) and larger entitlements in the Queensland section of the catchment. The CEWO has the potential to transfer entitlement from Queensland storages such as Glenlyon Dam into Pindari. Such an action was undertaken in to support the NSW stimulus flow. Further details of this event can be found in the next section. Table 1 - Summary of environmental water holdings Border Rivers catchment Jurisdiction NSW Commonwealth NSW Qld (medium) Qld (unsupplemented) Volume (ML) 4,000* ,159 4,474 *NSW stimulus flow only available when daily inflows into Pindari exceed 1,200 ML/day between April and August 2012/2013 Watering Summary Inflows in the previous two watering years triggered the availability of the Pindari stimulus flow, with a total of 8,000 ML available for environmental water delivery. The CEWO made available an additional 8,000 ML through the transfer of entitlement from Glenlyon storage. A model hydrograph (see Figure 3) was developed to mimic a natural event in the Severn River (NSW) from data collected from the Strathbogie gauge (Severn River) upstream of Pindari. Figure 3 Pindari stimulus flow proposed release: discharge from Pindari Dam and expected discharge at Mungindi (Source NOW) 5

11 At the commencement of the stimulus flow on the 3 rd December 2012, there was also significant irrigation demand from downstream general security licences. This led to only 895ML of Commonwealth water being required to meet the planned release strategy due to the volume of ordered water being released in conjunction with the stimulus action. In addition, the irrigation demand interrupted the planned recession strategy, with consumptive orders keeping flow in the river at Ashford well above the 2,000 ML/day level for an extended period following the cessation of stimulus releases. Figure 4 Severn River (Ashford) and Barwon River (Mungindi) 1st December to 15 th December 2012 (Source NOW). Note red arrows indicate stimulus flow event 6

12 Although the additional irrigation demand created an extended period of increased flow and assisted a range of ecological values within the Severn River, the combined impact of the stimulus release and high consumptive orders did have a significant effect on water temperatures within the river. As demonstrated in Figure 5, the commencement of irrigation demand in late November led to significant decreases in water temperature at Ashford (30 km downstream of Pindari) and within the Kwiambal National Park (70 km downstream of Pindari). These effects were exacerbated by the commencement of high flows associated with the stimulus release, suppressing temperatures by a further 4 degrees at Ashford and 2 degrees within Kwiambil NP. The cumulative impact of the irrigation demand and stimulus releases suppressed temperatures within the Severn River by more than 8 degrees Celsius. Figure 5 Temperature and flow data from Pindari stimulus release (Source NOW) Fish-specific watering actions The WSP for the Regulated Border Rivers lists pre-season cues to fish breeding as one of the major objectives of the stimulus flow. As such, Fisheries NSW were involved in the planning and delivery of the Pindari stimulus flow and fisheries outcomes were sought through both the direct benefits of a moderate river rise and indirectly through increases in river metabolism and micro/macroinvertebrate densities. Outside of the stimulus flow, there were no fish-specific watering actions undertaken in the Border Rivers catchment 7

13 Outcomes The outcomes of the Pindari stimulus release are summarised in the NOW publication, Pindari Dam Stimulus Flow an assessment of the December 2012 release ( The report identifies the key hydraulic outcomes that were met as part of the release strategy and discusses the potential impact on native fish breeding and recruitment, however there were no resources available for an intervention assessment of the impacts on native fish communities. Future Priorities Pindari Stimulus Flow The major consideration for future releases under the Pindari stimulus flow is the likely thermal effect on downstream habitats. While there are no specific fish data from the release event in 2012, temperature records from a number of sites and the published tolerances of native fish for breeding and survival indicate the release may have had short-term negative impacts on fish populations within the Severn River. Figure 6 highlights the impact of cold water pollution on spawning thresholds for native species in the nearby Namoi catchment. The water temperature of inflowing tributaries above Keepit Dam met or exceeded the thresholds for native species throughout the majority of their seasonal spawning windows, however the temperatures immediately downstream of Keepit failed to reach the thresholds for any of the listed native species. Water temperature downstream of Keepit Dam (Namoi River) Silver perch Catfish Golden perch 20 Murray cod 15 Downstream temp Carp 10 5 Upstream temp 0 Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Figure 6 Seasonal and temperature breeding thresholds Namoi River (Fisheries NSW, unpublished data) 8

14 Longer-term benefits from increased scour, lateral habitat connectivity and carbon and nutrient input may accrue and provide an overall benefit to the fish communities within the river, however the quantum of this is uncertain. The thermal effects did moderate as distance from the dam increased (see Figure 7), potentially providing both short and longer-term benefits to the fish community in downstream reaches. However these benefits will need to be considered within the context of the direct impacts downstream of Pindari storage. In the absence of additional data, utilising the Pindari stimulus flow at the beginning of the allocated period (ie from the 1 st August) would lessen the thermal impacts within the Severn River and downstream tributaries. Figure 7 Temperature and discharge at Mungindi (Barwon River) Future CEWO releases Integrating the downstream requirements of fish communities in the planning of environmental water held in Queensland storages is a priority for future management. Identifying shared and complementary objectives will result in the maximum possible benefit being derived from the resources available. 9

15 Gwydir The Gwydir Catchment The Gwydir River rises in the north-west of NSW, flowing west of the New England Tablelands and into the extensive Gwydir Wetland system. The large catchment receives input from a range of tributaries in the upland and slopes region, including the Booralong, Laura, Rocky and Copes Creek systems which all enter the main stem of the Gwydir upstream of the major regulating storage, Copeton Dam. The major unregulated input to the Gwydir system comes via the Horton Valley. Copeton Dam regulates flow to the lower sections of the Gwydir catchment and the through to the Gwydir wetland system. The Mehi, Carole, Moomin and Gil Gil Creeks along with the Gingham watercourse and Mallowa Creek all form part of a complex distributory network regulated through releases from Copeton Dam. Copeton supplies water for an extensive area of irrigated agriculture as well as delivering town water to urban centres, including Moree. Prior to the construction of Copeton Dam, the Gwydir system only connected the with the Barwon River during significant flood events, however since the regulation of the system and the delivery of water down the Mehi and Gil Gil/Carole systems, connectivity between the two systems is now more frequent. The extensive channelisation of distributory channels throughout the Gwydir Wetlands has resulted in an 85% reduction in its estimated 220,000ha area prior to river regulation. Figure 8 - The Gwydir Catchment (Source NSW OEH) 10

16 The Gwydir catchment experienced drier conditions in the watering year compared to two very wet years prior. Unregulated events in July 2012 and January/February 2013 were the major inflows into the system, with a smaller event in December Figure 9 summarises the Gwydir River flow at Pallamallawa (downstream of Copeton; upstream of the Gwydir wetlands). Figure /2013 River height and discharge data for the Gwydir River (Pallamallawa) Fish Condition The Sustainable Rivers Audit provides an overall fish condition rating of the Gwydir valley as Poor. Individual regions within the catchment ranged from Moderate (Slopes) to Very Poor (Montane and Upland). The slopes region biomass was dominated by alien species despite scoring comparatively well in terms of nativeness. Other notable features from the SRA included a significant proportion of alien species across all zones and a paucity of native species in Upland and Montane regions. An analysis of catch data from the NSW Freshwater Fish Database by Gilligan (Fisheries NSW; unpublished data) identified the Horton Valley as being the area of greatest aquatic biodiversity within the Gwydir catchment. The Horton is the largest unregulated sub-catchment within the valley, and as such is unaffected by cold water pollution and modification to the natural flow regime. These would appear to be critical factors in the persistence of the native fish population. Surveys conducted in 2007/08 recorded 11 native and 3 alien species of fish within the Gwydir Wetlands. Although representatives from the larger bodied species (such as Murray Cod) were recorded within the wetlands, these regions are typically dominated by smaller bodied species such as Australian Smelt and Gudgeons. 11

17 Environmental Water Allocations Surface water flows within the Gwydir catchment are managed through Water Sharing Plans (WSP) for both the Gwydir Regulated River and the unregulated catchments within the Horton Valley (Rocky Creek, Cobbadah, Upper and Lower Horton Water Sources). The Gwydir Regulated WSP protects the combined tributary inflows above Copeton up to 500ML/day and 50% of flows above that point thereafter. The equivalent of these inflows has to pass through to the Gwydir wetlands. On a long-term average basis, this protects a total of 56% of yearly flows for the environment. An additional Environmental Contingency Account (ECA) is credited water according to catchment conditions. See Table 2 for current ECA holdings. Supplementary access licenses also operate within the Gwydir. The Unregulated WSP for the Horton Valley restricts access depending on the flow class conditions within the river on any given day and an annual long-term average extraction limit. The WSP aims to protect low flow refugia for fish and other aquatic species and allow extraction during periods of higher flow. Adaptive environmental water entitlement within the Gwydir valley is held by both NSW Office of Environment and Heritage (OEH) and the Commonwealth Environmental Water Office (CEWO). Environmental watering decisions are largely guided by the Gwydir Environmental Contingency Allowance Operational Advisory Group (ECAOAG) chaired by the Border-Rivers Gwydir CMA. Both Commonwealth and state agencies retain autonomy over their decision-making, however all proposals are discussed by the ECAOAG prior to finalisation. Table 2 - Summary of environmental water holdings Namoi Valley Annual Entitlement NSW Holdings (ML) Commonwealth Holdings (ML) HS GS SA UR HS GS SA CV TLM UR 17, ,525 19,100 HS High Security; GS General Security SA Supplementary Access; UR Unregulated CV Conveyance; TLM The Living Murray 2012/2013 Watering Summary A total of 51,149ML of environmental water deliveries was made up of 41,026 ML of environmental water from orders made on Copeton Dam holdings and 10,123 ML from orders on announced Supplementary Licensed events during The goal was to achieve five to six months of inundation of wetland assets as the third year of a three year restoration program for the Gingham and Lower Gwydir systems. This was achieved through both environmental watering and natural inflows into the lower system. In addition, a 10,000ML trial was implemented in the Mallowa Creek system to assess the ability to deliver water and inundate a substantial area of wetland habitat. The estimated 1,600ha inundation of wetland and creek habitat exceeded the expected 1,000ha goal of the trial. 12

18 Fish-specific watering actions A range of wetland fish species are likely to have benefited from the delivery of environmental water to the Gingham, Lower Gwydir and Mallowa Creek systems, however no specific watering activities were targeted at enhancing native fish breeding and recruitment. To date, environmental water planning within the Gwydir has largely focussed on maximising the extent and duration of wetland inundation in conjunction with supporting the specific requirements of nesting colonial waterbirds. Outcomes The broader watering objectives of the Gwydir ECAOAG were met through a combination of environmental water delivery and natural inflows. There were no specific actions planned to support native fish, and as such there were no corresponding monitoring an assessment programs implemented to assess the outcomes for native fish. Future Priorities Following three significantly wet years and the finalisation of the Gwydir ECAOAG s strategy to build resilience in wetland communities over the corresponding period, the focus for the 13/14 watering year has moved towards reinstating a flow regime in line with the natural rates of rise and fall within tributaries. This has allowed the development of some fish-specific watering actions within the wetlands. The first delivery of water within the Gwydir aimed specifically at enhancing fish recruitment occurred in Oct/Nov of Two important features should form the basis of environmental water planning to support native fish communities within the Gwydir. The consideration of in-channel requirements of native fish between Copeton Dam and the Gwydir wetlands Environmental water planning and delivery within the Gwydir valley has focussed strongly on outcomes within the wetlands. While this has been a prudent measure given the loss of wetland extent and resilience in recent decades, the ecological values of the communities that lie between the regulated source (Copeton Dam) and the wetlands should not be ignored. This section of the river supports significant communities of native fish and the flow regime has been severely disrupted by the delivery of water for consumptive irrigation and/or wetland inundation priorities. An assessment of the fish communities within these reaches, their flow requirements in relation to their life histories and the impact of the current hydrograph should be undertaken. Synergies between wetland requirements and native fish species should be explored to maximise the outcomes from the available environmental water resource and better reflect a broad set of ecological priorities. 13

19 Establishing linkages between native fish requirements and environmental watering decisions within the wetlands The role of flow in the breeding and recruitment of native fish species is complex. Despite water being an essential component of native fish survival, no single watering strategy or event is likely to benefit all native fish species both within the wetlands or within the main river channel. Elevating the consideration of fish in the decision making process is essential to meet the broad suite of priorities held by the CEWO. The timing, duration and temperature of environmental water delivery should be better considered within the context of native fish requirements. The instigation of specific native fish flows in the Mehi and Carole Creeks in recent months is an important step forward for environmental water planning for native fish. The further development of this methodology will ultimately lead to more diverse and resilient native fish stocks within the broader Gwydir catchment. 14

20 The Namoi The Namoi Catchment The Namoi River rises on the western side of the Great Divide in northern NSW and flows westward until its confluence with the Barwon-Darling system near the town of Walgett. A typical large, low gradient inland system for the most part, the upland tributaries, including the Peel, MacDonald and the Manilla Rivers, make significant downstream contributions. The flow within the system is highly regulated through 3 major upland storages: Chaffey Dam on the Peel, Split Rock Dam on the Manilla River and Keepit Dam on the main stem of the Namoi. Flows are managed to meet the demands of large urban centres (including Tamworth, Gunnedah and Narrabri) as well as a substantial irrigated agricultural industry. Molle and Gunidgera Weirs downstream of Wee Waa provide additional re-regulating capacity within the system. Unregulated in-flows downstream of the storages are limited, with Cox s Creek and the Mooki River providing the most significant unregulated inputs into the system. Figure 10 The Namoi Catchment system (Source - MDBA) 15

21 Pre-development flows within the Namoi exhibited two distinct peaks in discharge during late Summer and mid-winter. Although extensive regulation and diversion have reduced the overall magnitude of current discharge, the seasonality of flows across the year remains largely intact (see Figure 2 below). Figure 11- Modelled monthly mean flows for the Namoi River at Bugilbone (source MDBA) The Namoi catchment experienced slightly above-average conditions in the watering year, with two unregulated events in February 2012 providing the basis for a fish-specific environmental water release (see below for further details). The previous two watering years (2010/11 and 2011/12) were characterised by a number of significant flood events, with the February 2012 event rivalling the largest flood on record. The period of above average rainfall followed drought conditions experienced throughout the catchment and the wider Murray-Darling Basin during the preceding decade. Fish Condition The Sustainable Rivers Audit provides an overall fish condition rating of the Namoi valley as Poor. The findings showed a general longitudinal deterioration in the native fish community from east to west within the catchment. The lowland and slopes regions were dominated by alien species and recorded poor nativeness scores. However work on the biodiversity hotpots for native fish species by Gilligan (NSW Freshwater Fish Biodiversity Hotspots, 2011) suggested that the fish community in the Namoi immediately downstream of Lake Keepit contained one of the more diverse assemblages throughout the state. The Namoi River itself forms part of the Lower Darling Endangered Ecological Community, with native fish impacted upon by 16

22 issues including riparian and floodplain clearing, barriers to fish passage, thermal pollution and lack of in-stream habitat diversity. Alien species form a significant proportion of the biomass within the catchment, especially in the lowland, slopes and valley regions. The reach between Gunnedah and Narrabri has been the subject of sustained habitat rehabilitation efforts in recent years as part of the Namoi Demonstration Reach activities and the ongoing Commonwealth-funded Connecting Riverine Communities in the Namoi project focussing on riparian rehabilitation efforts. The Demonstration Reach efforts have sought to focus investment and community attention on a specific reach of river to highlight the various rehabilitation options and demonstrate the tangible benefits that can be achieved through habitat restoration. Additional efforts downstream of Narrabri have seen the restoration of fish passage at Mollee, Weeta and Gunidgera Weirs, providing an extensive length of uninterrupted river downstream of Keepit Dam. Environmental Water Allocations The Water Sharing Plan for the Upper and Lower Namoi Regulated River water Sources dictates the water sharing rules throughout the Namoi catchment. The plan establishes overall extraction limits, sets thresholds for the start and finish of supplementary access and stipulates an end-of-system-flow rule for June, July and August when the combined storage volume of Keepit and Split Rock Dams exceeds 120,000ML. As evident in Table 3, the NSW Office of Environment and Heritage (OEH) holds no entitlement in the Namoi Valley, with the only adaptive environmental water holding being a small parcel managed by the Commonwealth Environmental Water Office (CEWO). Table 3- Summary of environmental water holdings Namoi Valley Annual Entitlement NSW Holdings (ML) Commonwealth Holdings (ML) HS GS SA UR HS GS SA CV TLM UR 6,323 HS High Security; GS General Security SA Supplementary Access; UR Unregulated CV Conveyance; TLM The Living Murray The annual volume of available water is dependent on storage and catchment conditions with up to 150% of holdings being able to be utilised in any given year, however three year totals cannot exceed 300% of annual entitlement. The allocation of Commonwealth holdings is coordinated through a committee chaired by the CEWO, which includes representatives from Fisheries NSW, NSW Office of Water (NOW), OEH and NSW State Water. 17

23 2012/2013 Watering Summary Given the comparatively small entitlement held in the Namoi valley, there is limited scope to develop stand-alone watering actions independent of antecedent conditions. As such, management planning for environmental allocation focuses on improving the quality and longevity of unregulated events within the catchment, or providing additional low-flows to support drought refugia in extended dry periods. The 2012/13 allocation focused on extending the recession of an unregulated event to maximise inundation of critical habitats such as benches, anabranches and large woody debris. Further detail can be found below. Fish-specific Watering Actions Given the prevailing catchment conditions and the likelihood of an unregulated event occurring during the Spring/Summer period (based on BOM predictions), planning focussed on extending the period of in-channel habitat inundation following a period of rainfall. Previous survey work undertaken by NOW identified a significant proportion of habitat types crucial to riverine productivity (ie benches, anabranches and large woody debris) having inundation thresholds within the 1,5000-4,000ML/day range. This range coincides with the greatest impact on flow under current regulated conditions (see Figure below), and was identified as being the component of the hydrograph upon which to focus the allocation of environmental water. Figure 12 Current arrangements versuss modelled pre-development flow duration curve for the Namoi River (at Wee Waa) 18

24 A suitable flow eventuated in February 2013, with unregulated inflows from Cox s Creek and the Mooki River providing the appropriate trigger at the Narrabri gauge. The CEWO made use of the full allocation of environmental water, delivering 7,200ML of water on the recession of the unregulated event. The impact of the allocation can be seen in Figure 13 below: Figure 13 Comparison of Namoi River flows (at Narrabri) with and without CEWH allocations The key outcome achieved was the extended recession, keeping flows in the river above the important 1,500 ML/day threshold for an additional 10 days. In addition to providing improved direct access for native fish to a range of habitat types, the watering action was aimed at increasing primary production through enhancing phytoplankton/zooplankton development, a major influence on larval survival and recruitment in inland rivers Outcomes Given the small volume of water and the limited capacity to identify measurable change in fish communities as a result of the watering action, no specific intervention monitoring was undertaken. The primary goal of the watering action was to provide an extended recession and prevent rapid decreases in flow and water level. Analysis of the hydrograph following the event indicated these objectives had been met. Future Priorities Significant change to the current watering priorities and associated actions are unlikely given the relatively small volumes of water held in environmental entitlement. Given the annual allocation is often swamped by consumptive demand 19

25 from the irrigation industry, it s not possible to develop a watering event in isolation from external factors. Within the context of available resources, the two broad options identified of extending the recession of unregulated events or delivering water in extended periods of low flow to support refuge sites appear the only practical options. Significant increases in the held environmental water portfolio for the Namoi are unlikely given the volumes identified under the draft Basin Plan and associated Sustainable Diversion Limits for each valley. Additional water purchased to meet shared downstream contributions may provide greater flexibility in future years, however these allocations will have to be managed to meet end-of-system requirements. 20

26 Macquarie The Macquarie Catchment The Macquarie River rises to the west of the Blue Mountains region within the Great Dividing Range. It flows primarily in a north-westerly direction through the major centres of Bathurst, Orange, Wellington and Dubbo. The main stem of the Macquarie receives significant tributary inflows from the Cudgegong, Fish, Little, Bell and Talbragar Rivers. Flow within the catchment is regulated by two major storages: Burrendong Dam near the town of Wellington on the main stem of the Macquarie and Windemere Dam on the Cudgegong. The regulated reach of the Cudgegong River joins the Macquarie upstream of Burrendong, providing re-regulating capacity. Downstream of Dubbo, the Macquarie River flows within flat alluvial plains and enters the Ramsar-listed Macquarie Marshes downstream of Warren. In periods of high flow, the Macquarie can make direct contact with the Barwon-Darling upstream of Brewarrina, or join the Bogan River through a complex network of distributory channels, including Duck and Crooked Creeks. The Bogan eventually joins the Barwon-Darling downstream of Brewarrina. Figure 14 - The Macquarie Catchment (Source NSW OEH) 21

27 The Macquarie catchment experienced relatively dry conditions in the watering year compared to the two previous very wet years. Following the millennium drought, 2010 and 2011 represented two of the wettest years on record throughout the Basin and delivered widespread unregulated events. Rainfall totals throughout the watering year were slightly below average, with only two tributary flow events of any significance (July and September 2012). Figure 11 summarises the Macquarie River flow at Warren Town weir, upstream of the Macquarie Marshes. The hydrograph indicates a sustained environmental watering event commencing in September 2012 (see below) within comparatively drier conditions throughout Figure /2013 flow conditions in the Macquarie River (Warren Town weir) Fish Condition The Sustainable Rivers Audit provides an overall fish condition rating of the Macquarie valley as Very Poor, with all sub-regions within the valley ranging between a Poor to Extremely Poor rating. Native fish have suffered significant declines in both abundance and diversity, with natives comprising only 21% of the total numbers and 38% of the total biomass within the catchment. Only a single Golden Perch and a single Murray Rainbowfish were sampled in the lowland areas where they would be expected to be abundant. An analysis of catch data from the NSW Freshwater Fish Database by Gilligan (Fisheries NSW, unpublished data) indicated the Macquarie catchment as a whole had higher biodiversity scores than adjacent catchments (Lachlan and Castlereagh), however in comparison to sites across all of NSW, biodiversity values were slightly below average. Cold water releases from Burrendong, which extend up to 300km downstream from the storage, and a significant number of instream barriers to fish passage have been implicated in declining native fish numbers (Lugg and Copeland, 2014; NSW DPI, 2006). 22

28 Environmental Water Allocations The allocation of water within the main stem of the Macquarie is governed by the Water Sharing Plan for the Macquarie and Cudgegong Regulated River Water Sources (WSP). The WSP outlines the mechanisms and allowances for water allocation and establishes a set of rules designed to provide protection for ecological processes within the catchment and share the resources amongst competing interests. The Macquarie Bogan Unregulated and Alluvial WSP also governs flow within the catchment. Environmental provisions in the regulated WSP are made through both rules-based or planned environmental water which aim to meet downstream flow targets in the Cudgegong below Windemere, and the allocation of adaptive or held environmental water within storages. The Macquarie/Cudgegong WSP provides for up to 160,000ML of entitlement per year, depending on catchment conditions. This environmental water allocation is separated into 2 sub-accounts, with their respective priorities being the maintenance of flow at Marebone Weir and the enhancement of native fish and colonial nesting waterbird breeding and recruitment opportunities. In addition, the NSW Government has secured additional entitlement through programs such as Riverbank and the NSW Wetland Recovery Program which is managed as adaptive environmental water. The Commonwealth Environmental Water Holder also holds significant entitlement within the Macquarie valley (see Table 4 for details). The Macquarie and Cudgegong Environmental Flow Reference group advise both the State and Commonwealth on the planning and delivery of environmental water holdings. Table 4 - Summary of environmental water holdings (total registered entitlement) Macquarie Valley Annual Entitlement NSW Holdings (ML) Commonwealth Holdings (ML) HS GS SA UR HS GS SA CV TLM UR 208,419* 1,452 2, ,891 6,292 *GS Holdings comprise of Environmental Water Allowances (sub groups I and II), and allocations from NSW Riverbank, RERP and the NSW Wetland Recovery Program. HS High Security; GS General Security SA Supplementary Access; UR Unregulated CV Conveyance; TLM The Living Murray 2012/2013 Watering Summary NSW OEH provided the following summary of the managed watering event: Environmental watering in the Macquarie River finished in early November after 115 days of managed flows. A total of 64,639 ML was delivered to the Macquarie Marshes including water allocated to the environment from the Water Sharing Plan (43,554ML), water previously purchased by the NSW government (10,984ML) and water delivered in collaboration with the Commonwealth Environmental Office (CEWO) (10,000ML). 23

29 Unfortunately for both the environment and other water users, catchment rainfall was relatively low over this period. One tributary flow in late September assisted the spread of water mid-event, but this was not followed by any other significant natural flow events. Preliminary results indicate the environmental flow inundated between 10,000 and 14,000 hectares, which was on-target for the maintenance objectives of the delivery. This area included much of the reedbeds of the northern and southern Marshes, and core areas of water couch meadows, mixed marsh and river red gum forests in the northern, eastern and southern Marshes. Areas higher on the floodplain, including some of the river red gum woodlands, have missed out this year. The dry conditions meant that no large-scale waterbird colonies formed this year. Some waterfowl breeding was observed (ducks, swans, magpie geese) and several endangered bird species were observed, including Australasian bittern and Australian painted snipe. (See for full details) Figure 16 Macquarie River environmental water delivery (Source: NSW OEH) Fish-specific watering actions The planning and delivery of environmental water in the Macquarie considered potential scenarios that would benefit the recruitment and dispersal of native fish. The Macquarie-Cudgegong WSP makes a specific allocation of environmental water for the purposes of enhancing native fish breeding and the Annual Environmental Watering Plan developed by the Macquarie EFRG included specific actions to either enhance the value of tributary flows in key native fish breeding periods through providing additional water to drown out fish passage barriers, or initiating a managed event to achieve similar outcomes if both water temperature and storage levels were favourable. 24

30 Outcomes The below-average rainfall conditions within the catchment limited the impact of environmental watering activities within the year. The planned watering actions for native fish didn t eventuate due to the lack of tributary in-flows during the identified window and the reduced storage level of Burrendong made a fully managed event impractical due to valve restrictions and temperature suppression from the storage. However the delivery of held environmental water to the Macquarie Marshes created increased flow and a degree of variability in channel inundation during the Spring/Summer period which may have provided assistance to a range of fish species and increased in overall riverine productivity (see Figures 16 and 17). No specific fish-based monitoring was undertaken during the watering year. The broader Macquarie Marshes watering actions met the maintenance objectives of 10-14,000ha of inundation, however there were no significant waterbird breeding events recorded. NSW OEH provided the following assessment of ecological outcomes: The weather conditions in were relatively dry and this was thought to influence both fauna responses and the condition of understorey vegetation in areas not flooded. This included no significant colonial bird breeding and relatively minor reported frog activity. Vegetation response is yet to be quantified but there was an observed increase in the extent and condition of aquatic and flood tolerant species and a continued suppression of invasive terrestrial plants (including many species of weeds) in the area that had been re-flooded this year. In addition, some areas of previously stressed river red gum (RRG) woodland appear to have undergone a substantial level of recovery. The re-flooding of RRG areas recorded as dead or very stressed in 2008 will allow re-mapping to confirm areas where trees have died and will not recover, which are evident from the air. Vegetation monitoring will also allow quantification of the level of recruitment of RRG seedlings. Observations suggest that conditions have been suitable for the establishment of seedlings in many areas. The area and period of inundation is expected to provide a full groundwater profile which will increase resilience to potentially dry conditions for the next few years (See for full details) Future Priorities The current effort to mitigate the impact of cold water pollution from the Burrendong outlet represents a substantial opportunity to deliver environmental water for positive native fish outcomes. To date, the benefits of augmenting unregulated tributary inflows using held environmental water were tempered through the associated reduction in downstream temperatures. Figure 17 demonstrates the inverse relationship between temperature and discharge within the Macquarie River at Dubbo during the critical October/November period. 25

31 Figure 17 Macquarie River discharge and temperature at Dubbo (August December 2012) Utilising held environmental water to assist in drowning out downstream barriers and inundating critical habitat features such as snags and benches can also result in keeping water temperature within the river below critical thresholds for native fish breeding. Mitigating cold water releases from Burrendong will remove a significant risk factor in the planning and delivery of environmental water and provide opportunities for improved breeding and recruitment of native fish species within an extensive reach of the Macquarie River. Future planning decisions should consider the hydrological requirements of the Macquarie channel between Burrendong and Marebone Weir as a priority area for restoration. The mitigation of cold water impacts is likely to enhance the ecological value of the reach, however maximising this improvement through considered delivery of environmental water is essential. Fish-specific planning considerations could include: Continuing the development of release scenarios around tributary inflows Unregulated events lead to increases in riverine productivity and river metabolism, often playing an integral role in the survival of larval fish and their subsequent recruitment into adult populations. Planning for the delivery of environmental water allocations to build on natural events can deliver significant benefits for native fish communities. The potential improvements to downstream water temperature within the Macquarie are likely to increase the efficacy of such a strategy. 26

32 Incorporating managed in-channel events for native fish outcomes There is growing evidence to support the importance of in-channel flow variability for native fish recruitment (Mallen-Cooper and Stuart, 2003; King et al., 2005; Zampatti and Leigh, 2013), suggesting the flood-pulse models previously proposed (e.g. Lake, 1967; Junk et al., 1989) may not adequately explain recruitment patterns within Murray-Darling Basin rivers. Although the capacity of the Burrendong outlet does not allow for a managed drownout of downstream barriers or the inundation of off-channel habitats, significant gains can still be achieved through moderate increases in discharge and river level if temperature and seasonal conditions are suitable. Expanding the window for enhancing unregulated events The planning decisions for environmental water allocation in conjunction with unregulated flow focused on the period between August and mid- October. While this period incorporates some important seasonal peaks in native fish breeding, potential gains could be achieved through extending this window well into the summer months (subject to operational constraints). Many native species exhibit adaptable spawning behaviour, allowing for a response to increased flow and riverine productivity through to early Autumn if temperature and catchment conditions are suitable. References Junk W. J, Bayley P. B, Sparks R. E. (1989). The flood pulse concept in river-floodplain systems. Canadian Special Publication of Fisheries and Aquatic Sciences 106: King A. J., Crook D. A., Koster W. M., Mahoney J. and Tonkin Z. (2005) Comparison of larval fish drift in the Lower Goulburn and mid-murray Rivers. Ecological Management and Restoration 6, Lake J. S Rearing experiments with five species of Australian freshwater fishes. I. Inducement to spawning. Australian Journal of Marine and Freshwater Research 18: Lugg A. and Copeland C. (2014) Review of cold water pollution in the Murray-Darling Basin and the impacts on fish communities. Ecological Management and Restoration Vol 15. No. 1, Mallen-Cooper M. and Stuart I. G. (2003) Age, growth and non-flood recruitment of two potamodromous fishes in a large semi-arid/temperate river system. River Research and Applications 19, NSW DPI (2006) Reducing the impact of weirs on aquatic habitat Central West Region. Report to the NSW Environmental Trust. 57 pages. Zampatti B. P. and Leigh S. J. (2013) Within-channel flows promote spawning and recruitment of Golden Perch, Macquaria ambigua ambigua implications for environmental flow management in the River Murray, Australia. Marine and Freshwater Research 14,

33 Lachlan The Lachlan Catchment The Lachlan River rises in the central tablelands of NSW, flowing west through the townships of Cowra, Forbes and Condobolin and into a complex network of distributory channels and wetlands. The Lachlan only connects with the Murrumbidgee River during significant flooding. It is a highly modified and regulated system. Wyangala Dam in the catchment headwaters impounds the Upper Lachlan and Abercrombie Rivers, and Lake Cargelligo and Lake Brewster in the mid and lower catchment provides significant re-regulating capacity. The main stem of the Lachlan and associated distributaries such as Willandra Creek are regulated via a series of weirs and regulators that provide stock and domestic water and irrigation capacity. Water flowing downstream of Lake Brewster separates into a series of effluent or distributary channels, including Willandra, Merrowie, Muggabar, Mirool and Merrimajeel Creeks, with two substantial terminal wetland systems, the Great Cumbung Swamp and the Lachlan Swamp, receiving much of the flow outside of flood events. Figure 18 - The Lachlan Catchment (Source NSW OEH) 28

34 The Lachlan catchment experienced drier conditions in the watering year compared to the two previous very wet years. Following the millennium drought, 2010 and 2011 represented two of the wettest years on record throughout the Basin and delivered widespread unregulated events. Rainfall totals throughout the watering year were slightly below average. Figure 15 summarises the Lachlan River flow at Willandra, highlighting the comparatively drier conditions throughout and the commencement of the Lower Lachlan environmental watering action in June 2013 (see below for further details). Figure flow conditions in the Lachlan River (Willandra weir) Fish Condition The Sustainable Rivers Audit provides an overall fish condition rating of the Lachlan valley as Extremely Poor. Almost all the sub-regions within the valley shared the Extremely Poor rating, with significant losses in native species richness and alien species accounting for 71% of fish biomass within the valley. The SRA2 report also noted a significant decline in fish condition since SRA1, however this may be explained through sampling being undertaken in extreme drought conditions. An analysis of catch data from the NSW Freshwater Fish Database by Gilligan (Fisheries NSW, unpublished data) indicated that the majority of the riverine section upstream of Lake Brewster was characterised by extremely low biodiversity values, with limited improvement in the main channel and effluent creeks downstream of Lake Brewster. A report by Price (2009) to the Lachlan CMA suggested the only species currently supporting viable self-sustaining populations were introduced, with all native species either locally extinct or characterised by patchy distribution or low abundance. 29

35 A report by NSW DPI to the Lachlan CMA (NSW DPI, 2006) identified a range of threatening process impacting upon native fish condition within the system. The combined impacts of cold water pollution, barriers to fish passage, degradation of riparian habitats and the significant impact of alien species within the river were all contributing to the suppression of native fish populations. Addressing the impacts of flow regulation can provide benefits to native fish communities, however it is important to acknowledge the range of stressors that are impacting upon native fish within the catchment. No single intervention is likely to significantly improve native fish populations in isolation. Environmental Water Allocations The allocation of water within the Lachlan is governed by the Lachlan Regulated River Water Sharing Plan (WSP). The WSP outlines the mechanisms and allowances for water allocation and establishes a set of rules designed to provide protection for ecological processes within the catchment. Water allocation within the Lachlan is dominated by General Security (GS) licenses. With no supplementary access within the system, GS allocations account for over 90% of the allocated shares within the system. Environmental water provisions in the Lachlan are made largely through flow rules, with the key features being: The protection of all water above the plan limit The implementation of winter/spring translucency arrangements at Wyangala to support increased flows in the lower Lachlan The allocation of 10,000ML of adaptive environmental water in both Wyangala and Lake Brewster when GS license allocations exceed 50%. Following the establishment of the Commonwealth Environmental Water Office, more than 85,000ML of General Security allocation has been purchased for adaptive environmental use. The CEWH have utilised the existing Lachlan Riverine Working Group as the framework to seek input on the allocation of Commonwealth water holdings. A summary of the combined state and Commonwealth environmental water holdings can be found in Table 5. Table 5 - Summary of environmental water holdings Lachlan Valley Annual Entitlement NSW Holdings (ML) Commonwealth Holdings (ML) HS GS SA UR HS GS SA CV TLM UR 1,000 44,569* ,923 *GS Holdings comprise of Environmental Contingency Allowances in Wyangala and Brewster that are only accessible when GS allocation exceeds 50% HS High Security; GS General Security SA Supplementary Access; UR Unregulated CV Conveyance; TLM The Living Murray 30

36 2012/2013 Watering Summary The most significant environmental watering event of the year commenced on the 7 th June 2013 and extended into the watering period. Commonwealth and NSW water holdings delivered a total of 88,854ML of water to the Lower Lachlan channel and effluent creeks over a 6 week period. The stated aims of the watering action were to support the resilience of wetland vegetation communities, in particular river red gum seedlings that had emerged following the 2010 and 2012 flooding, and support colonial bird breeding. Key wetlands and swamps targeted south-west of Hillston included the Lower Lachlan, Great Cumbung, Moon Moon and Baconian swamps, as well as Lake Ita and Lake Waljeers (OEH, 2103). The event inundated over 63,000ha of wetland and river channel habitat. Figure environmental flow in the Lower Lachlan (Hillston Weir) Fish-specific watering actions No specific fish outcomes were identified as part of the watering action. To date, environmental water planning within the Lachlan has largely focussed on maximising the extent and duration of wetland inundation in conjunction with supporting the specific requirements of nesting colonial waterbirds. Outcomes The broader watering objectives of the Lower Lachlan event were met through the environmental water delivery, with up to 75% of the target assets watered. There were no specific actions planned to support native fish, and as such there were no corresponding monitoring or assessment programs implemented to assess the outcomes for native fish. 31

37 Future Priorities The planning decisions for the watering year focussed on building on the gains in wetland vegetation and colonial waterbird populations that had accrued through unregulated events in previous years. The June 2013 watering action extended into the watering year and with the continuation of dry to very dry conditions across the catchment, this is likely to represent the only major watering action for the current watering period. There is scope to increase the consideration of native fish requirements within environmental water planning. The timing of environmental watering actions in the Lachlan has centred on the winter months to improve the extent of inundation within the low-gradient sections of the catchment, reduce the potential for negative water quality outcomes and avoid the channel-capacity restrictions in the lower Lachlan during the peak irrigation periods. Unfortunately this does not coincide with times of peak primary production within the river system or key life history stages of most native fish species. Four important considerations should form the basis of environmental water planning to support native fish communities within the Lachlan in future years: In-channel requirements of native fish Environmental water planning and delivery within the Lachlan valley has focussed strongly on outcomes within the wetlands. However, the ecological values of the riverine communities that previously existed between the regulated sources (Wyangala, Lake Cargelligo and Lake Brewster) and the lower valley wetland habitats should not be ignored. The native fish community within the Lachlan is in very poor condition and its long-term sustainability will depend on a suite of actions to address the threatening processes impacting upon native fish abundance. A key component of this will be considering native fish requirements in environmental water planning decisions. There is growing evidence to support the importance of in-channel flow variability for native fish recruitment (Mallen- Cooper and Stuart, 2003; King et al., 2005; Zampatti and Leigh, 2013), suggesting the flood-pulse models previously proposed (e.g. Lake, 1967; Junk et al., 1989) may not adequately explain recruitment patterns within Murray-Darling Basin rivers. While fluctuating irrigation demand can provide some variability within the flow regime, decoupling flow from catchment conditions and inconsistent longitudinal profiles due to large-scale extraction at specific points are likely to limit the benefits for native fish. The competing demands for channel capacity during times of peak demand needs to be further explored to ensure an adequate proportion of water can be allocated to the environment and higher flows in Spring/Summer can extend further downstream beyond the reaches of the channel that experience high levels of extraction. 32

38 Establishing linkages between native fish requirements and environmental watering decisions within the wetlands The role of flow in the breeding and recruitment of native fish species is complex. Despite water being an essential component of native fish survival, no single watering strategy or event is likely to benefit all native fish species both within the wetlands or within the main river channel. Elevating the consideration of fish in the decision making process is essential to meet the broad suite of priorities held by the CEWO. The timing, duration and temperature of environmental water delivery should be better considered within the context of native fish requirements. Synergies between wetland requirements and native fish species should be explored to maximise the outcomes from the available environmental water resource and better reflect a broad set of ecological priorities. Building on unregulated events Much of the environmental water planning within the Lachlan is based around rules-based water that stipulates translucency conditions of Wyangala Dam during in-flows. These rules will allow held or adaptive environmental water to maximise the outcomes of unregulated events if deliveries coincide with natural flows. Unregulated events lead to increases in riverine productivity and river metabolism, often playing an integral role in the survival of larval fish and their subsequent recruitment into adult populations. Planning for the delivery of environmental water allocations to build on natural events can deliver significant benefits for native fish communities. Maintaining longitudinal integrity of flow The complex nature of the Lachlan system, especially the significant reregulating capacity within Lake Cargelligo and Lake Brewster, presents a range of challenges in delivering flows for native fish. Native species respond to a range of cues of which flow volume and duration are just two factors. Temperature, water quality, water chemistry and concentration of microorganisms such as phytoplankton and zooplankton are all important factors influencing the response of native fish to flow events. The diversion of water into re-regulating storages has the potential to significantly alter one or all of these factors, potentially leading to differing responses from native fish. Opportunities to protect the integrity of flows within the system through the use of environmental water holdings should be explored. Specific actions may include meeting environmental flow orders through tributary inflows that have not been diverted into Lake Brewster or Lake Cargelligo. 33

39 References Junk W. J, Bayley P. B, Sparks R. E. (1989). The flood pulse concept in river-floodplain systems. Canadian Special Publication of Fisheries and Aquatic Sciences 106: King A. J., Crook D. A., Koster W. M., Mahoney J. and Tonkin Z. (2005) Comparison of larval fish drift in the Lower Goulburn and mid-murray Rivers. Ecological Management and Restoration 6, Lake J. S Rearing experiments with five species of Australian freshwater fishes. I. Inducement to spawning. Australian Journal of Marine and Freshwater Research 18: Mallen-Cooper M. and Stuart I. G. (2003) Age, growth and non-flood recruitment of two potamodromous fishes in a large semi-arid/temperate river system. River Research and Applications 19, Zampatti B. P. and Leigh S. J. (2013) Within-channel flows promote spawning and recruitment of Golden Perch, Macquaria ambigua ambigua implications for environmental flow management in the River Murray, Australia. Marine and Freshwater Research 14,

40 Murrumbidgee The Murrumbidgee Catchment The Murrumbidgee River rises to the west of the Great Dividing Range near Canberra and drains almost 11% of NSW. Flows within the valley are regulated by Blowering and Burrinjuck Dams in the upper reaches of the catchment. These two storages have a combined capacity in excess of 2,500GL. The major influences on river flow are the demand from regional centres, including Wagga Wagga, Narrandera and Leeton, as well as substantial areas of irrigated agriculture in the lower end of the valley. Tarcutta Creek and adjacent tributaries, which join the Murrumbidgee upstream of Wagga Wagga, are the major sources of unregulated flow into the system. During the watering year, the catchment experienced average to above average rainfall conditions with both of the major storages holding in excess of 90% capacity for the Spring/Summer period. A significant unregulated event in March 2012 and smaller events in July and August provided an opportunity for environmental water reserves to build on improved river flow conditions experienced since the easing of drought conditions in Figure 21 - The Murrumbidgee catchment (Source NSW OEH) 35

41 Fish Condition The Sustainable Rivers Audit 2 (SRA2) provides an overall Fish Condition Index rating for the Murrumbidgee as Extremely Poor. Within the catchment, the Lowland and Montane zones are classified as Very Poor, while the Slopes and Upland zones are Extremely Poor. Gilligan (2004) also described the fish community within the Murrumbidgee as being severely degraded, highlighting that alien species dominate both the number of individuals (71%) and the overall biomass (90%) within the system. A combination of altered natural flow regime, disruptions to lateral and longitudinal connectivity, thermal pollution and altered riparian, floodplain and catchment vegetation have all combined to place significant pressure on native species. These factors have both suppressed native species numbers and benefited highly resilient alien species such as carp. The catchment supports a stocked population of the threatened Trout Cod near the confluence of Tarcutta Creek and Murrumbidgee River. The NSW Fisheries Scientific Committee has classified the catchment below Burrinjuck and Blowering storages as part of the Lower Murray Endangered Ecological Community. The Lowbidgee experienced a significant hypoxic blackwater event in early 2011 after significant rainfall followed a prolonged period of drought. Widespread fish kills were reported, with large-bodied natives such as Murray Cod and Golden Perch making up a significant proportion of the affected individuals. Similar conditions in March 2012 were actively managed through the allocation of environmental water to reduce the severity of impacts. Environmental Water Allocations Planned Environmental Water (PEW) is legislated through the Murrumbidgee Regulated River Water Sharing Plan and stipulates minimum flow rules at Balranald Weir (the last gauge before the confluence with the Murray) and transparency rules relating to inflows for both Burrinjuck and Blowering storages. Both the Commonwealth and NSW Governments hold significant entitlement of Adaptive Environmental Water (AEW) within the Murrumbidgee valley, with holdings dominated by general security allocations. A summary of entitlement, allocations and releases are contained in the Table 6. Table 6 - Summary of environmental water holdings Murrumbidgee Valley Annual Entitlement Entitlement Releases NSW Holdings (ML) Commonwealth Holdings (ML) HS GS SA UR HS GS SA CV TLM HS High Security; GS General Security SA Supplementary Access; UR Unregulated CV Conveyance; TLM The Living Murray

42 The allocation of NSW holdings is managed by OEH through the Murrumbidgee Environmental Water Advisory Group (EWAG) and Commonwealth holdings are managed through both the CEWH and the MDBA Environmental Watering Group (for TLM allocations). Coordination of respective entitlement and environmental watering objectives saw the Murrumbidgee EWAG utilised as the principle forum for environmental water planning and delivery negotiations for both State and Commonwealth Governments. 2012/2013 Watering Summary For the first time in environmental water planning within the Murrumbidgee, the major environmental releases of the watering year were focussed on supporting a native fish breeding event. The Murrumbidgee Fish Flow utilised over 200,000ML of environmental water to support the recruitment of Murray Cod larvae into the system. Further detail of the watering event is contained below. In addition to the Murrumbidgee Fish Flow, the Murrumbidgee EWAG supported a series of small allocations to off-channel wetlands throughout the mid and lower Murrumbidgee valley. The Paika and Narwie wetland systems in the Lowbidgee and Telephone Bank within the Nimmie-Caira wetlands all received allocations to replenish flows towards the end of In early 2013, Gras Innes Swamp and Oak Creek within the recently disconnected Bundigerry Creek system also received environmental water allocations as did a range of smaller ephemeral wetland systems. Fish-specific watering actions The watering year saw the largest allocation of environmental water in the Basin specifically aimed at native fish recruitment. The Murrumbidgee Fish Flow aimed to support Murray Cod recruitment into the Lower Murrumbidgee fishery by maintaining a stable water level during the Murray Cod nesting season. The stable water levels, achieved through setting a threshold for discharge of 5,000ML/day at Darlington Point aimed to avoid the abandonment or desiccation of nests and increase the recruitment of juveniles into the adult population. The hydrograph and river height data below for October-November 2012 (see Figure 22) demonstrates the impact of environmental water delivery. Water levels throughout the breeding season in 2012 were maintained above the threshold and 5,000ML/day, which corresponds to a river height of 2.3m or above. This action enhanced the opportunity for nest establishment and the development of larval fish. 37

43 Figure 22 - Murrumbidgee River height and flow data (Darlington Point) Oct-Nov 2012 In contrast, the data from the corresponding period in 2011 (see Figure 23) shows significant fluctuations in both river height and discharge as a result of inconsistent demand from water users. This increases the risk of nest abandonment or desiccation of larval fish. Figure 23 - Murrumbidgee River height and flow data (Darlington Point) Oct-Nov

44 Additional efforts to water previously disconnected wetlands in the Lowbidgee were also accompanied by alien fish species control efforts. The installation of carp screens on the inlets to Cherax Swamp and Hobblers Lake has allowed the return of flows into previously disconnected systems while excluding adult carp. These actions are likely to support off-channel wetland specialist species which have been significantly impact within the Lower Murrumbidgee Valley. Outcomes Researchers from Fisheries NSW and Charles Sturt University have been monitoring a range of ecological responses to the watering event. Initial data suggests the Murrumbidgee Fish Flow was associated with an increase in larval density within the target reach. Additional sampling and age-class assessment in 2013 will determine whether the flow event led to a strong age-class of Murray Cod within the lower reaches of the Murrumbidgee. Videos produced by OEH summarising the Murrumbidgee Fish Flow and Cherax Swamp/Hobblers Lake watering projects can be found at: eupdate.htm Future Priorities The 2012/2013 watering year in the Murrumbidgee represented a major step forward in the management of environmental water for fisheries outcomes. The development of model hydrographs by the Aquatic Ecosystems Research team within Fisheries NSW provided clear direction for the Murrumbidgee EWAG to develop an environmental watering event focused on achieving outcomes for native aquatic species. Further refinement of operational protocols, such as the relationship between temperature thresholds and environmental water releases will improve future fisheries-based watering actions. The challenge in coming years will be to incorporate flow characteristics into planning decisions that, over time, support the full range of native aquatic species with flow-dependent life-histories. The Management Plan to use environmental water to enhance the Murrumbidgee River system for native fish (Cameron and Baumgartner, 2012) provides a framework for future decisions. The adoption of long-term watering plans that ensure a full range of aquatic species are supported by watering actions in accordance with their longevity, life history characteristics and conservation status will be a crucial goal for future management. 39

45 Edward-Wakool The Edward-Wakool System The Edward-Wakool system, located in the south west Riverina region of NSW, is an anabranch system of the Murray River characterised by a complex network of rivers, creeks and channels. The system is highly regulated via an array of large weirs and smaller regulating structures controlling the flow of water both into and within the Edward-Wakool. Major waterways within the system include the Edward, Niemur and Wakool Rivers, as well as Colligen, Yallakool and Merran Creeks. Water principally enters the system through a series of offtakes above Stevens Weir on the Edward River, however flow can also enter at other points along the main stem of the Murray or via Barbers and Thule Creeks when water is discharging from the Koondrook-Perricoota Forest. Deniliquin, on the Edward River, is the largest population centre within the system however demand for water is driven by agricultural production more than urban requirements. The magnitude of flow in the Edward-Wakool is largely influenced by upland catchment conditions and storage capacity. The extensive regulation of the system to support agricultural production has created a highly managed network, with relatively small channel capacities allowing individual reaches to reach bankfull conditions through managed inflows. Flooding within the Edward-Wakool from unregulated events occur during high flow events within the Murray valley, where flows exceed the combined channel capacities of the Edward and Murray Rivers Figure 24 - The Edward-Wakool system (Source CEWO) 40

46 During the watering year, the above-average rainfall conditions in the wider Murray catchment provided full entitlement to license holders within the Edward- Wakool. This in turn allowed for allocations of environmental water within Commonwealth and state portfolios to be utilised within the Edward-Wakool. Fish Condition The Edward-Wakool has historically held a diverse population of native fish, supporting productive recreational and commercial fisheries. Following the cessation of commercial fishing activity throughout NSW for finfish in 2001, the Edward-Wakool has remained a popular recreational angling precinct. However prolonged drought resulted in the disconnection of the system in 2007 and significant hypoxic blackwater events in 2009 and 2010 resulted in large-scale native fish mortality, particularly amongst larger-bodied species. An ongoing research partnership between the Commonwealth Environmental Water Office, Charles Sturt University, the Murray CMA and Fisheries NSW suggests that native fish numbers within the Edward-Wakool remain relatively robust, however individual reaches, including Colligen Creek, have displayed a significant reduction in numbers of large-bodied species since the 2010 blackwater event. Environmental Water Allocations The Water Sharing Plan for the NSW Murray and Lower Darling Regulated Rivers dictates the water sharing rules through the Edward-Wakool system. The annual draw-down for Stevens Weir limits the regulated flow into the Edward-Wakool. Unregulated events entering the Edward are shared alternately between the Edward and the Wakool Rivers. Given the significant role the Edward plays in downstream conveyance and the agricultural requirements within the Edward- Wakool system, the flow conditions within the system outside of significant unregulated events are primarily determined by demand from local and downstream users. Unlike other defined valleys within the Basin, the Edward-Wakool does not have a specific allocation of water, however receives allocations from the CEWO s broader Murray River account and NSW OEH holdings. A summary of the overall holdings within the NSW section of the Murray Valley can be found below. Table 7 Summary of environmental water holdings Murray Valley (NSW component) Annual Entitlement NSW Holdings (ML) Commonwealth Holdings (ML) HS GS SA UR TLM HS GS SA CV TLM UR 221,487 8, ,678 # 56 1,230 # - Includes 492ML of GS Lower Darling water HS High Security; GS General Security SA Supplementary Access; UR Unregulated CV Conveyance; TLM The Living Murray purchase measure 41

47 The allocation of NSW holdings is coordinated by the Murray CMA through a subcommittee of the Murray Environmental Watering Advisory Group. Representatives from the CMA and NSW OEH engage with a range of agency and stakeholder representatives to prioritise watering actions and submit orders to meet agreed objectives. The allocation of Commonwealth holdings is ultimately determined by the CEWO itself, however advice on watering options is provided through the same advisory group of agency and stakeholder representatives. 2012/2013 Watering Summary A total of 44,000ML was made available by the Commonwealth and NSW OEH for environmental watering actions in the Edward-Wakool during the watering year. The majority of the actions were aimed at achieving improved spawning and recruitment for native fish within Colligen and Yallakool Creeks (see below for further details). Additional water was supplied to Tuppal, Jimaringle and Cockran Creeks to maintain water quality, inundate vegetation and provide beneficial conditions for the recruitment of frogs. Fish-specific watering actions The 2012/2013 watering year saw five specific watering actions within the Edward- Wakool aimed at enhancing native fish breeding and recruitment. A summary of these events can be found in Table 8. Table 8 - Summary of environmental watering events in the Edward-Wakool (2012/2013) Waterway Objective Start/End Dates Volume (ML) Colligen Creek Yallakool Creek Yallakool Creek Colligen Creek Yallakool Creek In-stream flow pulses in Autumn for small-bodied generalists In-stream flow pulses in Autumn for small-bodied generalists In-stream flow pulses in late Summer for small-bodied generalists In-stream flow pulses in early Summer to induce a spawning response in large and medium bodied flow dependent spawners (Golden and Silver Perch) Inundate suitable nesting habitat for Murray Cod and enhance the chances of juvenile survival through maintaining nest inundation and promoting larval dispersal Commenced 13/03/13 Finished - 05/04/13 Commenced 13/03/13 Finished 05/04/13 Commenced 02/02/13 Finished 22/02/13 Commenced 02/11/12 Finished 17/12/12 Commenced 19/10/12 Finished 07/12/12 5,100 4,200 1,800 10,300 13,600 TOTAL 35,000 42

48 The rationale and associated hydrographs for each event were based on work by the Aquatic Ecosystems Research group within Fisheries NSW. The identification of specific hydrological requirements of a range of fish guilds or functional groups has given increased confidence to environmental water managers and community stakeholders to tailor flows for native fish outcomes. The relatively small channel capacity within the Edward-Wakool and the multiple channels within the system allows for a range of hydrographs targeting different species to be achieved within a single season. Three separate events focussed on small fluctuations to enhance the outcomes of small-bodied generalists, a peak flow followed by a managed recession was instigated in Colligen Creek to induce a spawning response among large and medium bodied flow-dependent spawners (such as Golden Perch and Silver Perch) and an extended elevated river level during early Summer in the Yallakool was aimed at improving recruitment of Murray Cod into the populations by enhancing larval survival. All five of these events are evident in the discharge and river height plots below. Figure 25 - Yallakool Creek height and flow data (Yallakool Regulator) Oct Apr 2013 (Note red arrows indicate commencement of watering events) 43

49 Figure 26 - Colligen Creek height and flow data (Colligen regulator) Oct Apr 2013 (Note red arrows indicate commencement of watering events) Outcomes Researchers from NSW Fisheries, Charles Sturt University, Monash University and the Murray CMA have been monitoring environmental watering in the Edward Wakool system. Recent findings indicate a small number of significant responses to in-channel environmental watering, however the legacy of events such as the hypoxic blackwater occurrences, especially within Colligen Creek, are likely to be suppressing any large-scale and measurable changes in the local fish community. This environmental watering has contributed to the maintenance of ecological health and resilience within the native fish population, but the timing, magnitude and duration of watering events were not sufficient to make a measurable improvement in the health and resilience of the fish population. Long-term fish monitoring, fish movement and ecosystem monitoring is required to determine a greater understanding ecological responses to water delivery. Future Priorities The successful delivery of environmental water within the Edward-Wakool and the community acceptance for watering actions is the result of a sustained effort to engage and involve a diverse range of stakeholders. The priority placed on the issue by the Murray CMA has fostered a culture of acceptance and trust amongst landholders, anglers and state and Commonwealth agencies. The maintenance of this relationship will be central to the ongoing success of watering actions within the system. 44

50 The unique geomorphology of the Edward-Wakool system combined with its highly regulated nature allows fine-scale control over watering actions. In contrast to many other valleys, this allows a range of watering actions targeting a variety of fish species to be implemented within a single watering season. Therefore consideration of long-term management plans and the inter-annual priorities for watering will focus more on how prominent a specific functional group was in water delivery decisions in previous seasons, rather than considering the seasonal intervals between events. The previous work developed to support fish and flows within the Edward-Wakool (see has been a key driver in efforts to increase the focus on native fish within environmental water planning. Enhancing our understanding of water delivery in relation to unregulated events will also be critical for future decisions. In highly regulated environments such as the Edward-Wakool, achieving optimal hydraulic conditions to support the life history of specific fish may not be overly difficult, however gaining confidence that these managed events can elicit the same response to more natural events will be crucial for future planning. The ongoing effort to support native fish recruitment is an example of the role of environmental watering in restoration efforts. Native fish populations within much of the Edward-Wakool system were severely impacted by hypoxic blackwater events in 2009 and The prudent use of environmental water as a restoration measure has significant potential within similar environments. 45

51 Murray/Lower Darling The Murray/Lower Darling system The Murray-Darling Basin is the largest connected river system in Australia, dominated by the Murray and Darling catchments. The Murray rises in the Australian Alps and forms the NSW-Victorian border for much of its journey into South Australia. The Murray River is a highly regulated system, with the major storages of Lake Hume and Dartmouth Dam providing significant regulating capacity. The river itself is interspersed with a series of smaller dams and weirs, controlling flow to the substantial area of irrigated agriculture in the Lower Murray and providing most of the domestic and commercial water needs of South Australia. The major settlements of Albury-Wodonga and Mildura are amongst many population centres situated on or near the river. The Darling River rises in southern Queensland and flows in a south westerly direction until its confluence with the Murray at Wentworth. The Darling River is largely unregulated above the Menindee Lakes system, however the Lower Darling reach is highly influenced by the implementation of the various storage and release scenarios for Menindee Lakes. The Lower Darling management unit is considered to be the main stem of the Darling River downstream of Menindee Lakes. For the purposes of this summary, the Edward-Wakool system and it associated environmental watering activities are addressed in a separate section within this report (see previous section). Figure 27 The Murray/Lower Darling system (Source NSW OEH) 46

52 The watering year commenced with significant volume in most of the Basin storages and an unregulated flow event in August/September, however the period from September 2012 to June 13 was characterised by very hot and dry conditions. An unregulated event originating from ex-tropical cyclone Oswald in January created in-flows into the Darling system, and resulted in the overall in-flows into the system exceeding the long-term average, despite the relatively dry catchment conditions. This event was captured within the Menindee Lakes and is not reflected within the hydrograph at Wentworth for the watering year (Figure 28). Figure 28 The Murray Wentworth watering year (Source NSW Office of Water) Fish Condition The Sustainable Rivers Audit 2 described the fish communities of the Central and Lower Murray and the Darling River as ranging from Poor to Very Poor. The Central sections of the Murray displayed significant reductions in the number of native species compared to reference conditions, however the reach did hold fewer alien species than many other catchments in the Basin. This trend did not continue further down the valley, with the fish assemblage of the Lower section of the Murray being dominated by alien species and low native species abundance. The MDBA s Native Fish Strategy estimated native fish populations across the Basin as a whole are at 10% of pre-european levels, however Gilligan (Fisheries NSW unpublished data) identified the main stem of the Murray downstream of Yarrawonga and the Darling downstream of Menindee to be amongst the most diverse native fish populations in NSW. 47

53 Environmental Water Allocations The Water Sharing Plan for the NSW Murray and Lower Darling Regulated Rivers (WSP) dictates the water sharing rules throughout the system. The WSP aims to equitably share water across a variety of sectors (ie. agriculture, industrial, environment, domestic). The WSP makes provision for environmental water to be allocated for the suppression of blue-green algae, the health of the Barmah-Millewa Forest and the establishment of adaptive environmental water licenses. A substantial environmental water allocation within the Murray/Lower Darling originated from the Living Murray Initiative, a Commonwealth program that combined water purchases with on-ground works to enhance the environmental values of seven Icon Sites throughout the Murray Valley. Additional water is held by the Commonwealth Environmental Water Office, the bulk of which exists with General Security licenses. NSW OEH has a comparatively smaller holding of High Security and conveyance water. Table 9 - Summary of environmental water holdings Murray Valley (NSW share) Annual Entitlement NSW Holdings (ML) Commonwealth Holdings (ML) HS GS SA CV TLM HS GS SA CV TL UR M , ,487 12,600* 327, , HS High Security; GS General Security SA Supplementary Access; UR Unregulated CV Conveyance; TLM The Living Murray purchase measure * Includes 394ML of HS in Lower Darling water ** Includes 795ML of GS in Lower Darling water The allocation of holdings is coordinated by the Murray Environmental Watering Advisory Group (EWAG), however the specific decisions regarding water holdings under The Living Murray (TLM) is authorised by the Environmental Watering Group coordinated by the MDBA in accordance with the TLM Annual Environmental Watering Plan. (See The EWAG, chaired by the Murray CMA and comprising various agency and stakeholder representatives, identifies potential actions and prioritises watering events to meet agreed objectives. The allocation of Commonwealth holdings is ultimately determined by the CEWO itself, however advice on watering options is provided through the same advisory group of agency and stakeholder representatives. 48

54 2012/2013 Watering Summary A total of 66,442ML was made available by the Commonwealth, MDBA and NSW OEH for environmental watering actions in the Murray/Lower Darling valleys during the 2012/13 watering year. The actions covering 13 different project areas were aimed at connecting a range of lateral wetland habitats to build resilience in vegetation communities, promote nesting opportunities for waterbirds and minimise rapid fluctuations in water levels. Table 9 summarises the adaptive environmental watering actions within the Murray/Lower Darling during the 2012/13 watering year. Table 10 : List of Murray Darling Valleys wetlands watered during the season with NSW AEW and/or CEWO allocations (source NSW OEH) Jimaringle, Cockran Wetland Gynong Tueloga and Gwynnes Creeks Location AEW Volume Diverted (ML) CEWO Volume Diverted (ML) Area Inund ated (Ha) Delivery Time Mid- ~ 85 Murray ,000 km 24 August - 20 November 2012 Mid- Murray September - 29 September 2012 Mid- Murray September - 2 September December - 8 December 2012 Comersdale Mid- Murray September - 21 September October October 2012 Tuppal Creek 10 October December Mid (4,103ML) Murray , km 15 April - 2 May 2013 (674.3ML) Yallakool Creek , October - 7 December 2012 Mid ~ 45 2 February - 22 February 2013 Murray km 13 March - 1 April 2013 Mid- Reed Beds Murray ~ October January 2013 Colligen Creek Mid ,261 ~ 40 2 November - 17 December 2012 Murray km 13 March - 1 April 2013 Lower Bingerra Murray March - 30 March 2013 Sandridge Mid- Murray March - 15 March 2013 Murray Irrigation Private wetlands Mid- Murray March - 30 April 2013 Lower Thegoa Lagoon Murray June - 29 June 2013 Lower Bottle Bend Reserve Murray June - 11 July 2013 TRADE Water from NSW AEW regulated river conveyance licence Water from NSW AEW high security licence Water from CEWO 49

55 Fish-specific watering actions Apart from the excellent outcomes pursued within the Edward-Wakool system (see above), environmental watering actions during 2012/2013 within the Murray/Lower Darling did not have a focus on fish and fish habitat. It is expected however that a range of small bodied species that utilise off-channel habitats are likely to have benefitted through the inundation of lateral habitats during the course of the watering year. Outcomes No specific fisheries outcomes were monitored across the Murray/Lower Darling events except in the Edward-Wakool. OEH staff completed a range of monitoring activities at watering sites to investigate the response of vegetation, frog and waterbird communities. The findings of these investigations can be found in the OEH summary report, available at: at1213.pdf. Future Priorities The ongoing efforts within the Edward-Wakool provide an excellent template for the consideration of fish in the development of watering priorities across the Basin. The identification of specific requirements to support native fish life histories as opposed to the more general assumption that more water will benefit fish is an important step in the long-term conservation of native fish species. The delivery of environmental water throughout the Murray/Lower Darling region would be enhanced through expanding the approach undertaken within the Edward-Wakool to broader contexts. The competing priorities impacting upon the main channels of the Murray and Darling present a range of challenges, especially the development of hydrological variability critical to a range of riverine processes. However opportunities such as an increase in late-winter/early-spring flows to address the impacts of seasonal inversion and reducing sharp changes in discharge from fluctuating irrigation demand have potential to assist native fish production. The potential benefits for off-channel specialists from targeted inundation of central and lower Murray wetlands could be better quantified if the current extent and distribution of these species was better understood. Many of the species have become locally extinct through decades of highly regulated flow and a lack (or excess) of lateral connectivity. As a result, targeted environmental flow events will do little to aid their recovery if populations are not present to respond to changed conditions. 50

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