Commonwealth environmental water use options 2013-14: Border Rivers 1 Cover image credit: Severn River, Kwiambal National Park, Border Rivers. Photo by Clare d’Arcy © CEWO Acknowledgement of the Traditional Owners of the Murray-Darling Basin The Commonwealth Environmental Water Office respectfully acknowledges the Traditional Owners, their Elders past and present, their Nations of the Murray–Darling Basin, and their cultural, social, environmental, spiritual and economic connection to their lands and waters. This report should be cited as ‘Commonwealth environmental water use options 2013-14: Border Rivers’. Published by the Commonwealth Environmental Water Holder for the Australian Government. © Commonwealth of Australia 2013. This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced by any process without prior written permission from the Commonwealth. Requests and enquiries concerning reproduction and rights should be addressed to Department of Sustainability, Environment, Water, Populations and Communities, Public Affairs, GPO Box 787 Canberra ACT 2601 or email public.affairs@environment.gov.au Information presented in this document may be copied for personal use or published for education purposes, provided that any extracts are fully acknowledged. The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of the Australian Government or the Minister for Sustainability, Environment, Water, Population and Communities. While reasonable efforts have been made to ensure that the contents of this publication are factually correct, the Commonwealth does not accept responsibility for the accuracy or completeness of the contents, and shall not be liable for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the contents of this publication 2 Commonwealth environmental water use options 2013-14: Border Rivers Table of contents 1. Introduction ........................................................................................................ 5 2. Context for water use in 2013–14 in the Border Rivers .................................... 6 2.1. Delivering environmental water to the Border Rivers ......................................................... 6 2.2. Operational and management considerations for 2013–14 in the Border Rivers ......... 8 2.3. Valley condition ....................................................................................................................... 10 3. Water availability ............................................................................................. 11 3.1. Commonwealth environmental water holdings in the Border Rivers for 2013–14 ...... 11 3.2. Other sources of environmental water allocations .......................................................... 11 3.3. Natural or unregulated flows and planned environmental water ................................ 11 4. Planning for water use in the Border Rivers in 2013-14 ................................. 14 4.1. Planning for a range of inflows in 2013-14 .......................................................................... 14 4.2. Implementing watering actions throughout the year ...................................................... 14 5. Water use options and the Basin Plan’s environmental watering plan objectives ......................................................................................................... 15 5.1. Demonstrating how Commonwealth environmental water in 2013–14 will contribute to the Basin Plan’s Environmental Watering Plan objectives – Border Rivers.................... 15 6. Water use options for 2013–14 ........................................................................ 16 6.1. Watering options...................................................................................................................... 16 6.2. Assessment of environmental watering options ................................................................ 21 7. Accounting for the use of Commonwealth environmental water .............. 23 7.1. Water use accounting ............................................................................................................ 23 7.2. Operational monitoring .......................................................................................................... 23 8. Partnerships ...................................................................................................... 24 9. Bibliography ..................................................................................................... 25 3 List of Figures Figure 1: Map of the Border Rivers .............................................................................................................. 7 Figure 2: How inflows may vary and impact on water resource availability over the course of 2013–14 in the Border Rivers, from a starting point of Moderate to High resource availability. ... 14 List of Tables Table 1: Operational considerations for the Border River Valley in 2013–14. ..................................... 9 Table 2: Commonwealth environmental water holdings in the Border Rivers as at 30 April 2013. ......................................................................................................................................................................... 11 Table 3: Other potential sources of environmental water in the Border Rivers catchment for 2013–14. .......................................................................................................................................................... 12 Table 4: Expected outcomes from the use of Commonwealth environmental water in the Border Rivers. ................................................................................................................................................. 15 Table 5: Potential watering options for 2013–14 for the Border River valley. .................................... 17 4 1. Introduction This document is designed to be read in conjunction with the Commonwealth environmental water use options 2013-14: Planning approach, which outlines the approach to planning for the use of Commonwealth environmental water this coming water year. The planning document provides the context for key aspects of the approach including determining resource availability, the expected outcomes from watering actions and the relationship between the function of the Commonwealth Environmental Water Office (the Office) and the Basin Plan. This document outlines watering options for the use of Commonwealth environmental water in the Border Rivers this year. The options, which describe potential watering actions, series of actions, or watering strategies, do not represent a commitment for water use. Consistent with the Office’s framework, decisions to make water available for any of the potential options will be subject to an assessment against five published criteria (available from the Office’s website) and seasonal, operational and management considerations at the time of the action. All relevant watering actions will be assessed to ensure the best possible use of environmental water within the relevant catchment and across the Murray-Darling Basin and having regard to the Murray-Darling Basin Authority’s Basin annual environmental watering priorities, once published. 5 2. Context for water use in 2013–14 in the Border Rivers 2.1. Delivering environmental water to the Border Rivers The Border Rivers is based around the Macintyre River and the Dumaresq River, which merge upstream of Boggabilla and continue as the Macintyre River. The Macintyre River ultimately becomes the Barwon River. The Macintyre River's main tributary is the NSW Severn River. The principal tributaries of the Dumaresq River are the Beardy River and Ottley's Creek. Below Goondiwindi, effluent creeks and anabranches break off the Macintyre River channel and form a meandering complex of billabongs and wetlands across an extensive floodplain. These breakouts include Callandoon and Dingo Creeks in Queensland and Whalan Creek and Boomi River in NSW. The most significant tributary in the floodplain zone is the Weir River (Queensland). Below the confluence of the Weir and Macintyre Rivers, the main stream becomes the Barwon River. Collectively, public storages providing regulated supplies have a capacity of 635 GL, comprising Pindari Dam on the Severn River in NSW (312 GL), Glenlyon Dam on Pike Creek in Queensland (254 GL) and Coolmunda Dam on Macintyre Brook in Queensland (69 GL). The volume of on-farm storage is comparable to public storage, reflecting the importance of unregulated flows (diversion of river and overland flows) to irrigation supplies in the catchment. On average, the majority of water use in the Border Rivers catchment is based on opportunistic access to unregulated flows (supplementary water access in NSW and unsupplemented water allocations in Queensland). Regulated water entitlements (supplemented water allocations in Queensland, high and general security licences in NSW) comprise a smaller component of overall water use. Environmental water demand in the Border Rivers includes baseflow and in-channel fresh requirements. Baseflows target habitat availability, nutrient cycling, fish passage, and riparian health outcomes, and are limited to in-channel flows which can be satisfied through relatively low release rates from dams. In-channel fresh events aim to improve nutrient cycling, facilitate the migration and recruitment of native fish species, and enhance anabranch connection and riverine woodlands. Regulated releases from storages can be timed to coincide with unregulated flows in order to contribute to in-channel fresh requirements. Where possible, environmental water will be managed to benefit multiple sites en route to maximise the efficiency and effectiveness of water use. The Commonwealth’s unregulated flow access entitlements cannot be actively ‘delivered’ and are left in-stream during unregulated flow conditions. This augments unregulated water already protected from extraction in the system and contributes to local and downstream flow benefits. The extent of how far benefits flow through the system depends on the circumstances for individual flow events. Benefits may extend downstream to the Barwon–Darling. Figure 1 below shows a map of the Border Rivers. 6 Figure 1: Map of the Border Rivers (CSIRO 2007). 7 2.2. Operational and management considerations for 2013–14 in the Border Rivers The achievement of desired environmental outcomes will be closely related to the careful coordination of the timing of environmental water releases to coincide with unregulated flows in the Border Rivers. Regulated releases (including irrigation orders, stock and domestic replenishment flows or NSW stimulus flow) also offer opportunities to “piggy back” Commonwealth environmental water and increase the potential for environmental objectives to be achieved and assist with delivery efficiency. In 2012-13, river operators in the NSW and QLD developed a draft framework to manage the delivery of QLD allocation from the NSW Pindari Dam. On a trial basis, 626 ML of Commonwealth QLD allocation was successfully delivered in accordance with this framework without any impacts on other licence holder’s water availability or reliability. Applications to trial the delivery of water under this proposed framework are considered by the state resource operators on a case by case basis. Operational considerations such as delivery methods, opportunities, constraints and risks will differ depending on the inflow scenario and are summarised in Table 1. Operational considerations are assessed against inflow scenarios which are represented by annual exceedance probability (AEP), that is, the number of years that a given inflow volume is equalled or exceeded, expressed as a percentage. Throughout the year operational and management considerations will be addressed as decisions are taken to make water available for use and as these decisions are implemented. This will include refining the ecological objectives, assessing operational feasibility and potential risks and the ongoing monitoring of the seasonal outlook and river conditions. 8 Table 1: Operational considerations for the Border River Valley in 2013–14. Inflow scenario Very low (90% AEP1) Low (75% AEP) Moderate (50% AEP) High (25% AEP) Very high (10% AEP) Opportunities Manage the recession of unregulated flows to provide for a more natural flow pattern. Use environmental water in conjunction with, or to maximise the environmental benefit of, unregulated river flows. Use environmental water in conjunction with, or to maximise the environmental benefit of, other water orders. Accrediting and shepherding of flows once they enter Barwon Darling system (once agreed arrangements are in place). Constraints Natural flows meet environmental flow requirements, reducing the need for and effectiveness of the release of environmental water. Delivery options are limited due to high unregulated flows resulting in reduced channel capacity, limiting the operation of river infrastructure and inhibiting additional releases from storages. Maximum annual usage on current regulated entitlements is 0.3 GL (NSW) and 11.7 GL (Queensland) and 5.9 GL unregulated flow access entitlements2. Flow thresholds for existing river infrastructure may constrain the delivery of environmental water. Risks* Percentages refer to the probability of exceedance based on historical inflows for the valley, i.e. there is a 90 per cent chance that actual flows will be greater than that amount. 1 Based on holdings as at 30 April 2013, please note that Queensland Border Rivers (Medium) entitlements have an 85% account limit at any one time. 2 9 Inflow scenario Very low (90% AEP1) Low (75% AEP) Moderate (50% AEP) High (25% AEP) Very high (10% AEP) The provision of Commonwealth environmental water must consider potential inundation impacts to property and infrastructure. *See Section 6.2 for more information on risk management. 2.3. Valley condition Between 2002 and 2010 the Border Rivers catchment received low inflows due to a long period of drought, which coupled with river regulation, had a significant effect on the environmental condition of the valley. The MDBA released its second Sustainable Rivers Audit report in 2012 (based on data collected from 2008 to 2010) and concluded that the Border Rivers valley was in poor river ecosystem health. While the Border Rivers valley was recognised as having good hydrology with moderate physical form, fish and macroinvertebrate communities, the valley was rated as poor for riparian vegetation communities (MDBA 2012b). Some moderate inflows occurred during this period in 2003–04, but drought-breaking inflows were experienced in 2010–11 with further high inflows experienced across the valley in 2011–12. Consecutive years of widespread flooding and overbank flows have provided significant longitudinal and lateral connection of river channel and fringing wetlands. This would have provided breeding and recruitment opportunities for a range of native aquatic species and an improvement in their condition. The 2012–13 water year returned to drier than average conditions in the Border River valley. To late January 2013, rainfall was very much below average across the entire valley, while above average temperatures were experienced particularly throughout summer. These conditions resulted in high system demand (irrigation orders) in the catchment. Unregulated flow events in February and March 2013, peaking at 30,000 ML/day at Mungindi in early February 2013, transmitted nutrients and carbon inputs to the river, drowned out weirs, inundated benches and riparian vegetation and connected fringing wetlands and lagoons along the length of the Macintyre River. In December 2012, 0.9 GL of Commonwealth environmental water was delivered in combination with a NSW stimulus flow (refer Section 3.3) and irrigation orders. Early monitoring indicates the stimulus achieved its objectives to: disturb and reset algal communities, stimulate production through all levels of the aquatic food chain, inundate riparian areas and provide aquatic species access to a diversity of aquatic habitats to feed and shelter. Improvements to threatened species and vegetation regeneration resulting from consecutive years of unregulated events will require support in the coming water years to ensure their survival and to continue to improve their condition. 10 3. Water availability 3.1. Commonwealth environmental water holdings in the Border Rivers for 2013–14 Commonwealth environmental water holdings available for use in 2013–14 in the Border Rivers are shown in Table 2 below. Table 2: Commonwealth environmental water holdings in the Border Rivers as at 30 April 2013. Entitlement type Entitlement held (GL) Long-term average annual yield (GL) Carryover from 2012–13 (GL)1 Forecast water availability for 2013–14 (GL) NSW Border Rivers (General B) 0.3 0.1 0 0.1-0.2 Qld Border Rivers (Medium) 11.5 3.8 8.3 11.5 Qld Macintyre Brook (General B) 0.2 0.2 0.4 0.4 Border Rivers – Severn (Unsupplemented) 1.3 0.5 N/A Up to 1.0 Border Rivers Macintyre (Unsupplemented) 3.3 1.3 N/A Up to 4.9 Total 16.2 5.9 8.7 ~12 (0.2 available within use limits.) Notes: 1. Future decisions about use, transfers and the ability to deliver already approved actions will affect expected carryover from 2012-13. 2. The forecast for unregulated water is to receive up to the maximum allowed use, subject to the announcement of trigger flows. Forecasts are based on the best available information including State forecasts and historical inflow scenarios. Forecasts include carryover from 2012-13. Forecasts for are given to the nearest whole gigalitre for regulated entitlements. Forecast total is exclusive of unregulated water. The full list of Commonwealth environmental water holdings can be found at http://www.environment.gov.au/ewater/about/holdings.html and is updated monthly. A portfolio management statement for the Border Rivers is available at http://www.environment.gov.au/ewater/publications/index.html. 3.2. Other sources of environmental water allocations There are currently no other sources of held environmental water in the Border Rivers. 3.3. Natural or unregulated flows and planned environmental water In addition to water entitlements held by the Commonwealth, environmental demands may also be met via natural or unregulated flows and water provided for the environment under rules in state water plans (referred to as ‘planned environmental water’). Other sources of environmental water may be available to supplement Commonwealth environmental water delivery in the catchment during 2013–14 (Table 3). The Bureau of Meteorology provides a 11 seasonal streamflow forecasting service, which estimates the potential for low, median or high flows for the coming three months ahead. The NSW Border Rivers Water Sharing Plan includes the high conservation value reach of the Severn (NSW) and Macintyre Rivers downstream of Pindari Dam. The Pindari Dam stimulus flow and translucency rules (i.e. inflows up to 50 ML/day between September and May are passed downstream; up to 200 ML/day between June-August) attempts to mitigate the impacts of the dam on the natural hydrological regime and aquatic ecosystems in the Severn River (NSW). Commonwealth environmental water would be in addition to these flows and provide increased benefits to this asset. NSW and Queensland have water management rules in place for the Macintyre River downstream of Goondiwindi. These rules aim to provide additional flows to this area. There is an end of system low flow rule that protects tributary inflows to maintain flows at Mungindi on the Barwon above 100 ML/day (September–March). When unregulated flow events arise, announcements are made constraining the times, locations and rates for the take of water under unregulated flow access entitlements. There are complex rules for determining these announcements. For example, access to freshes below the junction of the Macintyre River and the Dumaresq River that arise from inflows above Goondiwindi, does not commence until the total flow over two consecutive days exceeds 10,000 ML. Access ceases when the total lows over two consecutive days at Goondiwindi drops below 3,650 ML. In dry to medium years it is likely that some of these events will be protected in order to meet downstream requirements for freshes in the Barwon-Darling River (although in very dry years such events are less likely to occur). Commonwealth environmental water would be in addition to these rules and provide increased benefits to this asset. Table 3: Other potential sources of environmental water in the Border Rivers catchment for 2013–14. Source Stimulus flow Pindari Dam Instrument Management Authority Potential Allocation NSW Water Sharing Plan NSW OEH and NOW NSW State Water (delivery) 4 GL/year reserved for a stimulus flow, provided trigger conditions are achieved. Can be accrued to a maximum of 8 GL (4 GL available in 2013-14). NSW State Water Up to 0.05 GL/day (September–May) Translucency flows Pindari Dam Up to 0.2 GL/day (June– August) Maximum of 30 GL/year Improving low flows at end of system NSW Water Sharing Plan High flow protection NSW-Queensland Intergovernmental Agreement on the Border Rivers 2008 Low flow allowance Coolmunda Dam Queensland Border Rivers Resource Operations Plan QLD DNRM NSW State Water/NOW Tributary inflows protected to maintain flow at Mungindi on the Barwon above 0.1 GL/day (September–March) 25% of unregulated flows in main trunk and Macintyre River in NSW protected from point of inflow to Mungindi Queensland SunWater 12 The first 0.1 GL/day of inflows released to 6 GL/year. 13 4. Planning for water use in the Border Rivers in 2013-14 4.1. Planning for a range of inflows in 2013-14 In addition to influencing opportunities, constraints and risks in relation to environmental watering (see Table 1), inflows are a primary driver of resource availability. Resource availability also reflects a combination of the allocations available to the Commonwealth Environmental Water Holder (Section 3.1 above) as well as natural or unregulated flows and planned environmental water (Section 3.3). Given the variable rainfall experienced across the Basin, inflows are difficult to accurately forecast. As shown in Table 2, carryover from 2012–13 for the Border Rivers is likely to be approximately 8.7 GL. Forecast early season allocations (up to 31 July 2013) are likely to be minimal (as a result of relatively low inflows in autumn 2013 and high carryover account balance). Consideration of this allocation range relative to the total entitlement volume (Table 2) and the full range of inflows that may be possible suggests that resource availability early in 2013–14 may be moderate to high. From this starting point, the full range of possible inflows suggest that resource availability over the course of the year could be between low and very high, and unlikely to become very low (Figure 2). As such, the water use options described in Section 6 have been considered for a range of resource availability between low and very high. Figure 2: How inflows may vary and impact on water resource availability over the course of 2013–14 in the Border Rivers, from a starting point of Moderate to High resource availability. 4.2. Implementing watering actions throughout the year Resource availability will change over the course of 2013–14 as new allocation announcements are made, and water is used or traded. Climatic conditions will also affect the potential for inflows. The Office will regularly review allocations against environmental entitlements and seasonal streamflow forecasts over the course of the year to assess resource availability. This assessment, along with up-to-date information on environmental needs and the operational and management conditions (Section 2) will allow the watering options in Section 6 to be refined for implementation as required. 14 5. Water use options and the Basin Plan’s environmental watering plan objectives 5.1. Demonstrating how Commonwealth environmental water in 2013–14 will contribute to the Basin Plan’s Environmental Watering Plan objectives – Border Rivers Commonwealth environmental water use options for the Border Rivers in 2013–14 include the following two flow types: base flows freshes, and overbank. These flow types are illustrated in Figure 3 of the document Commonwealth environmental water use options 2013-14: Planning approach. Wetlands are also expected to be inundated. The ecological response from delivering Commonwealth environmental water is reflected in the expected outcomes. The Commonwealth Environmental Water Office (the Office) has used the best available science to determine how the expected outcomes of Commonwealth environmental water contribute towards the objectives of the Basin Plan’s environmental watering plan. Table 4 shows the expected outcomes that may be derived from Commonwealth environmental watering using different flow types in the Border Rivers and the relevant Basin Plan objectives. Table 4: Expected outcomes from the use of Commonwealth environmental water in the Border Rivers. Flow Type Expected outcomes for 2013–14 Contributions to longer term outcomes Contribution to the following Basin Plan objective Base flows Dissolved oxygen Chemical Water Quality Base flows and freshes Fish reproduction Landscape fish diversity Biodiversity Connectivity Ecosystem function Fish condition Hydrological connectivity Biotic dispersal Base flows and overbank Primary production Process Refuge Recovery 15 Resilience 6. Water use options for 2013–14 6.1. Watering options Potential watering options for 2013–14 have been developed for the Border Rivers, which reflect the approach to supply Commonwealth environmental water to contribute to the overall environmental objectives under the Basin Plan’s environmental watering plan. These watering options have been designed to specifically enable the adaptation of actions across several potential inflow scenarios. This provides flexibility for water use to best complement natural inflows. Options have not been developed for high flow scenarios (and the relevant resource availability). During high inflows, unregulated flows are likely to meet ecological objectives and (given the small volume of regulated holdings) there may be limited need for and effectiveness from deliveries of up to 10.9 GL of Commonwealth environmental water. Broadly, the aim of Commonwealth environmental watering in the Border Rivers during 2013–14 will be to support in-stream outcomes, with a focus on the on-going environmental recovery that commenced following the breaking of the drought (see Section 2.3). Watering actions will focus on contributing to in-stream objectives, including contributing to low flows and freshes to maintain in-channel habitat and support the growth and survival of native aquatic species. Any volumes described in the options tables below are approximations only. The final volume of Commonwealth environmental water made available will depend on river conditions at the time of use, other environmental water contributions and in consideration of Basin-wide needs. The water use options identified do not represent a commitment for use, nor do they reflect all the possible water use options available. Additional water use options may be identified throughout the water year. The Office welcomes information from the community on how environmental water can best be used and managed. If you have any comments or suggestions, please call 1800 218 478 or send an email to: ewater@environment.gov.au. 16 Table 5: Potential watering options for 2013–14 for the Border River valley. Applicable level(s) of resource availability (see Section 4) Low Moderate High Very High Option 1 – Border Rivers Fresh Flow Contribute to fresh flows to improve the health of in-stream habitat and water quality and to support native aquatic species by providing improved opportunities for fish to access breeding habitat and to feed and shelter. Option unlikely to be pursued under this resource availability. Option 2 – Border Rivers Base Flow Contribute to base flows to flush and maintain healthy habitats in river pools and provide greater access to a range of in-stream habitats and at times of very low flow, critical habitat. Option unlikely to be pursued under this resource availability. Option 3 – Border Rivers Infrastructure assisted delivery Contribute to availability of suitable refuge habitat by ensuring the persistence of pools and contributing to water quality within pools. Option unlikely to be pursued under this resource availability. Note: Under certain resource availabilities, options may be not pursued for a variety of reasons including that environmental demand may be met by unregulated flows, the may be limited need for and effectiveness from deliveries of small holdings, and that constraints and/or risks may limit the ability to deliver environmental water. 17 Option 1 – Border River Fresh Flow Catchment: Border Rivers Complex: Border Rivers Catchment River Flows Site: Severn River/Dumaresq River/Lower Macintyre River (including anabranches) Applicable level(s) of resource availability: Low to High Relevant flow component: Expected inundation extent: Base flows Floodplain inundation Fresh Wetland inundation Bank-full flows Over-bank flows/Terminal Wetland Summary of watering option: The purpose of the option is to enhance in-stream flows by contributing to fresh flows. This will contribute to the health of in-stream habitat and water quality, as well as contribute to high primary productivity within the Border Rivers. Connecting and extending the wetted period of floodplain and wetland habitat with the main channel will contribute to nutrient and food production for the aquatic ecological community. The provision of Commonwealth environmental water in combination with unregulated freshes will support native fish condition and reproduction by providing improved opportunities for fish to access breeding habitat and to feed and shelter. The option has the potential to benefit large bodied native fish including the EPBC listed Murray cod as well as small bodied native fish, including threatened species such as the purple spotted gudgeon, which require access to off-channel habitat to breed and disperse. To achieve this outcome, regulated Commonwealth environmental water could supplement: o o an unregulated fresh(s) by increasing the duration with a managed rate of fall to baseflow rates and/or NSW stimulus flow releases or other source of water with a release regime designed to mimic a natural flow pattern downstream of storage, During unregulated flow conditions, the Commonwealth’s unregulated flow access entitlements cannot be actively ‘delivered’ and are left in-stream, augmenting planned environmental water already in the system. Timing All year (most likely Spring to Autumn) Volume of Commonwealth environmental water Up to 17.8 GL (including up to 5.9 GL unregulated flow access entitlement, if access triggered) Operational considerations and feasibility: This option would supplement unregulated flow or regulated flow (irrigation supply or stimulus flow or stock and domestic replenishment flow). Commonwealth environmental water could complement a decision by NSW Office of Water to provide up to 4 GL of planned environmental water as a stimulus flow downstream of Pindari Dam. Release regime from storages will be designed to mimic a natural flow pattern and use up to the outlet maximum flow capacity for the storage. Under natural conditions, rain generated fresh flows contribute to high primary productivity within the Severn River/Dumaresq River/Macintyre River associated with carbon inputs from runoff and high flows inundating benches and connecting anabranches. o Unregulated freshes that exceed 700 ML/day to 4500 ML/day downstream of Kanowna are likely to improve nutrient and carbon cycling and provide greater availability to habitat by wetting banks, benches and bars present in the Lower Macintyre River 18 channel. o Unregulated freshes that exceed 4,000 ML/day to 9000 ML/day downstream of Mungindi are likely to provide maximum morphological anabranch diversity in the Lower Macintyre River. Depending on the timing of the event certain aquatic species will be advantaged according to their biological requirements. As conditions develop the flow regime and objectives targeted will be refined. Native fish species in the Gwydir river system typically reproduce during spring and summer associated with an increase in flow and temperatures. Deliveries in winter may provide adult fish opportunities to feed and grow before they reproduce. Providing flows that access in-channel habitat in September to October would coincide with the smaller reproduction ‘window’ (water temperature related) of Murray cod and catfish. Larvae and juveniles of these species have been recorded in fish surveys in late September-early October in northern Basin valleys. Deliveries during spring to summer may support larval dispersal and contribute to larval/juvenile fish growth and survival. Water orders will be developed in conjunction with NSW State Water Corporation and Queensland Department of Natural Resources and Mines to ensure operational feasibility and environmental objectives can be achieved. 19 Option 2 – Border River Base Flow Catchment: Border Rivers Complex: Border Rivers Catchment River Flows Site: Severn River/Dumaresq River/Macintyre Brook/Macintyre River channel Applicable level(s) of resource availability: Low to High Relevant flow component: Expected inundation extent: Base flows Floodplain inundation Fresh Wetland inundation Bank-full flows Over-bank flows/Terminal Wetland Summary of watering option: The purpose of the option is to: provide flows to refresh or provide hydrological connectivity to in-stream habitat; ensure the persistence of pools as refuge; and reduce the risk of degrading water quality conditions, particularly low dissolved oxygen levels. The proposed option would maintain habitat diversity and or essential refuge habitat for aquatic species during periods of low to no flow. To achieve this outcome, Commonwealth environmental water may contribute to flows up to 500 ML/day at Mungindi. The precise rate will be determined based on antecedent conditions and flows through the season. Timing All year (most likely late winter to Autumn) Volume of Commonwealth environmental water Up to 10.9 GL Operational considerations and feasibility: This delivery option will be delivered by supplementing other water sources (such as irrigation deliveries or planned environmental water) to provide longitudinal hydrological connectivity and extend the duration of access to a range of habitats. Under a sustained low inflow scenario, Commonwealth environmental water deliveries could contribute to maintaining natural water levels in pools and flowing water in channel to keep in-stream habitat wet, maintain safe water quality, and provide drought refuge for a range of aquatic species. The presence or absence of critical habitat is the key factor influencing aquatic species condition. Water orders will be developed in conjunction with river operators to ensure operational feasibility and environmental objectives can be achieved. Commonwealth environmental water will be delivered and managed within the normal water delivery arrangements. 20 Option 3 – Border River fringing wetlands Catchment: Border Rivers Complex: Other Border Rivers Catchment Sites Site: Macintyre River fringing wetlands (e.g. Morella Watercourse/Pungbougal/Boobera system) Applicable level(s) of resource availability: Low to High Relevant flow component: Expected inundation extent: Base flows Floodplain inundation Fresh Wetland inundation Bank-full flows Over-bank flows Summary of watering option: The purpose of the option is to: provide flows to ensure the persistence of pools as refuge; contribute to water quality within pools; and maintain the health of riparian vegetation. Commonwealth environmental water provided to the floodplain lagoons fringing the Macintyre River (e.g. Morella Watercourse/Pungbougal/Boobera system), would be pumped from the river as per normal irrigator water ordering practice. The precise rate will be determined based on antecedent conditions and flows through the season. Timing All year (most likely late winter to Autumn) Volume of Commonwealth environmental water Up to 3 GL Operational considerations and feasibility: Floodplain lagoons of the mid Macintyre River depend on overbank and flooding flows and local catchment inflows to reconnect and refill. These flows have dimished as a result of river regulation and the development of irrigated agriculture. Some benefit may be achieved via pumping to discrete sites. This option may be in scope under very low to high inflow scenarios as some fringing wetlands in the Border Rivers are only connected to the main channel during large unregulated events. Options have not been developed for a very high inflow scenario in recognition that at these times, large areas of the Border Rivers valley (including the target sites) would likely be experiencing flooding. The provision of additional environmental water is not required in these conditions and would likely cause adverse third party impacts. In some cases access to channels will need to be negotiated with landholders and agreement for inundation of privately owned wetlands will need to be sought. Some modifications to works to allow this to occur, and to allow water to appropriately flow between lagoons, could also be required. Water orders will be developed in conjunction with river operators to ensure operational feasibility and environmental objectives can be achieved. Commonwealth environmental water will be delivered and managed within the normal water delivery arrangements. 6.2. Assessment of environmental watering options The proposed watering options will be assessed closer to the proposed timing for delivery using the criteria for assessing environmental watering actions. This assessment will form part of the Commonwealth Environmental Water Office’s assessment of seasonal, operational and management considerations and will inform a recommendation to the Commonwealth 21 Environmental Water Holder to approve water use. A description of these criteria is provided in the Framework for Determining Commonwealth Environmental Water Use which is available at: www.environment.gov.au/water/publications/action/pubs/cehw-framework.pdf. This assessment will include a comprehensive risk assessment which is subject to the prevailing valley and river flow conditions, and will consider proposed costs, delivery, monitoring and accounting arrangements, and potential third party impacts. Any additional watering options identified during the course of the year will also be subject to an assessment against the criteria. 22 7. Accounting for the use of Commonwealth environmental water 7.1. Water use accounting In the Border Rivers the Office is responsible for making arrangements to deliver Commonwealth environment water with river operators such as State Water Corporation and Queensland Department of Natural Resource and Mines. River flows will be accounted for at storages or at downstream flow gauges and will be reported to the Office by State Water Corporation and Queensland Department of Natural Resource and Mines. Where applicable, water delivered to individual wetland sites will be accounted at flow gauges or metered pumps at those sites. 7.2. Operational monitoring Operational monitoring helps assess whether water has been delivered as planned [e.g. the volumes, timing (frequency and duration), and location and flow rates of water delivered] and can include observations of immediate environmental responses. This monitoring is mostly undertaken by delivery partners in conjunction with the Office. In the Border River valley, this includes NSW State Water Corporation, NSW Office of Water and Queensland Department of Natural Resource and Mines. Delivery partners provide regular operational monitoring updates to the Office. The operational monitoring requirements are set out in the Office’s Operational Monitoring template. Key parameters required through operational monitoring are: Date of Commonwealth environmental water delivery (commencement and finish) Point of debit/delivery (both if they are different) Volume of Commonwealth environmental water delivered (provided on a weekly basis) Flow rate that water is delivered at (hydrograph of delivery if possible) Monitoring associated with identified risks. 23 8. Partnerships The Office has consulted with a range of stakeholders to develop the Commonwealth environmental water use options for the Border Rivers for 2013–14. These include: Environmental Water Scientific Advisory Panel Murray-Darling Basin Authority New South Wales Office of Water Queensland Department of Natural Resource and Mines Queensland Murray Darling Commission New South Wales Office of Environment and Heritage New South Wales Department of Primary Industries Border Rivers Gwydir Catchment Management Authority NSW State Water Corporation. The Office will continue to work with stakeholders and other interested community members (through briefing the State Water Border Rivers Customer Service Committee and the Border Rivers Environmental Watering Network) in the planning, delivery, management and monitoring of Commonwealth environmental water. 24 9. Bibliography Alluvium (2010) Key ecosystem functions and their environmental water requirements, Report by Alluvium for Murray-Darling Basin Authority, Canberra. Australian Wetlands Pty Ltd (2009) Border Rivers Demonstration Reach Whole of Life Plan, Queensland Murray‐Darling Committee Inc., Toowoomba, Queensland. Balcombe S, Arthington A, Thoms M and Wilson G (2011) “Fish assemblage patterns across a gradient of flow regulation in an Australian dryland river system”. River Research and Applications, 27: 168–183. Balcombe SR, Bunn SE, Davies PM and McKenzie-Smith FJ (2005) Variability of fish diets between dry and flood periods in an arid zone floodplain river. Journal of Fish Biology 67: 1552– 1567. Bureau of Meteorology (2012) monthly rainfall deciles for Australia, viewed 1 July 2012, <http://www.bom.gov.au/jsp/awap/rain/index.jsp?colour=colour&time=latest&step=0&map= decile&period=12month&area=ns>. Border Rivers Commission (2011) Dumaresq-Barwon Border Rivers Commission Annual Report 2009–10. Border Rivers-Gwydir Catchment Management Authority ‘Wetlands of the Lower Macintyre Valley’, http://brg.cma.nsw.gov.au/index.php?page=wetlands_of_the_lower_macintyre_valley <accessed 17/06/2011> Bunn SE and Arthington AH (2002) Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity. Environmental Management 30: 492–507. Butcher A (2007) Characteristics of fish fauna of the Macintyre and Dumaresq Rivers and Macintyre Brook. A report to the Queensland Murray‐Darling Committee. QLD Department of Primary Industries and Fisheries. CSIRO (2007) Water availability in the Border Rivers. A report to the Australian Government from the CSIRO Murray-Darling Basin Sustainable Yields Project. CSIRO, Australia. Davies P, Harris J, Hillman T and Walker K (2008) SRA Report 1: A Report on the Ecological Health of Rivers in the Murray–Darling Basin, 2004–2007. Prepared by the Independent Sustainable Rivers Audit Group for the Murray– Darling Basin Ministerial Council. Department of Natural Resources and Water (2009) Queensland’s water resource plans annual report 2007–08. Queensland Department of Natural Resources and Water, Brisbane. Department of Environment and Resource Management (2010) Annual report 2009–10 Queensland’s water resource plans – Border Rivers, Department of Environment and Resource Management, Queensland. Department of Environment and Resource Management (2011) Border Rivers Resource operations Plan, Department of Environment and Resource Management, Queensland. Department of Environment and Resource Management (2011) Conceptual Model Case Study Series, Aquatic connectivity: Macintyre River, Department of Environment and Resource Management publication, Queensland. Department of Primary Industries (2011) Key Fish Assets Namoi: Gunnedah-Wee Waa. NSW Department of Primary Industries (Fisheries). 25 Department of Water and Energy (2009) Water Sharing Plan NSW Border Rivers regulated river water source: Background document, Department of Water and Energy, Sydney. Environment Australia (2001) A Directory of Important Wetlands in Australia, Third Edition. Environment Australia, Canberra. Green D, Ali A, Petrovic J, Burrell M and Moss P (2012) Water resource and management overview: Border Rivers Catchment, NSW Department of Primary Industries, Sydney Humphries P and Lake P (2000) “Fish larvae and the management of regulated rivers.” Regulated Rivers: Research & Management, 16: 421–432. Hutchison M, Butcher A, Kirkwood J, Mayer D, Chikott K and Backhouse S (2008) Mesoscale movements of small and medium-sized fish in the Murray-Darling Basin. Murray Darling Basin Commission, Canberra. MDBC Publication No. 41/08 Kingsford R (1999) “Managing the water of the Border Rivers in Australia: Irrigation, government and the wetland environment.” Wetlands Ecology and Management 7: 25–35. Lugg A (in prep 2011) Outline of low flow requirements to sustain fish habitats and native fish communities in the rivers of the Murray Darling Basin. Draft low flow requirements paper version 4 May 2011. NSW DPI Fisheries. McGinness HM, Thoms MC and Southwell MR (2002) Connectivity and fragmentation of flood plain-river exchanges in a semi-arid, anabranching river system. International Association of Hydrological Sciences 276, 19–26. Medeiros SEF and Arthington AH (2008) The importance of zooplankton in the diets of three native fish species in floodplain waterholes of a dryland river, the Macintyre River, Australia. Hydrobiologia 614:19–31. Medeiros ESF and Arthington AH (2010) Allochthonous and autochthonous carbon sources for fish in floodplain lagoons of an Australian dryland river. Environmental Biology of Fishes 90:1–17. Murray-Darling Basin Authority (2011) The proposed “environmentally sustainable level of take” for surface water of the Murray-Darling Basin: Methods and outcomes, MDBA publication no: 226/11, Murray-Darling Basin Authority, Canberra. Murray-Darling Basin Authority (2012) Assessment of environmental water requirements for the proposed Basin Plan: Lower Border Rivers (in-channel flows). Licensed from the Murray–Darling Basin Authority, under a Creative Commons Attribution 3.0 Australia Licence. National Parks and Wildlife Service (2004) Kwiambal National Park and Ashford Caves Crown Reserve: Draft Plan of Management, NSW National Parks and Wildlife Service, Tenterfield, NSW. NSW Department of Primary Industries (2006) NSW Silver Perch Recovery Plan. NSW Department of Primary Industries, Port Stephens. NSW Department of Primary Industries (2006) Reducing the Impact of Weirs on Aquatic Habitat – New South Wales Detailed Weir Review. Border Rivers / Gwydir CMA region. Report to the New South Wales Environmental Trust. NSW Department of Primary Industries, Flemington, NSW. NSW Office of Water (2011a) Border Rivers Catchment http://www.water.nsw.gov.au/Watermanagement/Basins-and-catchments/Border-Rivers-catchment/Border-Riverscatchment/default.aspx <accessed 17/07/2011> 26 NSW Office of Water (2011b) Environmental flow response and socio-economic monitoring. Border Rivers – progress report 2009, NSW Office of Water, Sydney. NSW waterinfo (2012) viewed 1 July 2012 <http://waterinfo.nsw.gov.au/water.shtml?ppbm=SURFACE_WATER&rs&3&rskm_url>. Reid M (2006) The importance of connectivity between patches in riverine landscapes: an example from the lower Macintyre River, Murray Darling Basin. Oral presentation to 45th Australian Society of Limnology Congress, 25029 September 2006, Albury-Wodonga. Reid MA, Delong MD and Thoms MC (2011) The influence of hydrological connectivity on food web structure in floodplain lakes. River Research and Applications. doi: 10.1002/rra.1491. Southwell MR (2008) Floodplains as Dynamic Mosaics: Sediment and Nutrient patches in a Large Lowland Riverine Landscape. PhD Thesis, University of Canberra, Australia. SKM (2009) Environmental Values and Watering Priorities for the Northern Murray Darling Basin. Report prepared by Sinclair Knight Merz for the Department of Environment, Water, Heritage and the Arts. September 2009. State Water (2012) State Water, Pindari Dam, 1 July 2012, http://www.statewater.com.au/Water+Delivery/Dams/Pindari+Dam. Thoms M, Southwell M, McGinness H (2005) “Floodplain-river ecosystems; fragmentation and water resources development.” Geomorphology, 71, 126–138 Wilson GG and Ellison TL (2010) Pindari Dam fish monitoring project. Final report to the New South Wales Office of Water. University of New England, Armidale, New South Wales. 59pp. Winemiller KO (1996) Factors driving temporal and spatial variation in aquatic floodplain food webs. In Polis, G. A. & K. O. Winemiller (eds), Food Webs: Integration of Patterns and Dynamics, Vol. 472. Chapman and Hall, New York: 298–312. 27