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Commonwealth environmental water use options 2014–15:

Namoi River Valley

Cover image credit: Namoi River, Gunnedah. Photo: Andrew Warden © CEWO.

Acknowledgement of the traditional owners of the Murray-Darling BasinThe 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.

© Copyright Commonwealth of Australia, 2014.

Commonwealth environmental water use options 2014–15: Namoi River Valley is licensed by the Commonwealth of Australia for use under a Creative Commons By Attribution 3.0 Australia licence with the exception of the Coat of Arms of the Commonwealth of Australia, the logo of the agency responsible for publishing the report, content supplied by third parties, and any images depicting people. For licence conditions see: http://creativecommons.org/licenses/by/3.0/au/

This report should be attributed as ‘Commonwealth environmental water use options 2014–15: Namoi River Valley, Commonwealth of Australia 2014’.

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 the Environment. 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.

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Commonwealth environmental water use options 2014–15: Namoi River Valley

Table of contents1. Background..........................................................................5

1.1. Demonstrating how Commonwealth environmental water in 2014–15 will contribute to the Basin Plan’s environmental watering plan objectives – Namoi River Valley..........................................................................................................5

2. Context for water use in 2014–15 in the Namoi River Valley....72.1. Delivering environmental water to the Namoi River Valley..................................72.2. Operational and management considerations for 2014–15 in the Namoi River

Valley...................................................................................................................82.3. Valley condition....................................................................................................9

3. Water availability................................................................113.1. Commonwealth environmental water holdings in the Namoi River Valley for

2014–15.............................................................................................................113.2. Other sources of environmental water allocations.............................................113.3. Natural or unregulated flows and planned environmental water........................11

4. Planning for water use in the Namoi River Valley in 2014–15.134.1. Planning for a range of inflows in 2014–15.........................................................134.2. Implementing watering actions throughout the year.........................................14

5. Water use options for 2014–15............................................155.1. Summary of watering options............................................................................155.2. Assessment of environmental watering options.................................................175.3. Options contributing to the Basin Annual Environmental Watering Priorities.....23

6. Accounting for the use of Commonwealth environmental water..........................................................................................24

6.1. Water use accounting........................................................................................246.2. Monitoring..........................................................................................................24

6.2.1. Operational monitoring...............................................................................246.2.2. Long term intervention monitoring..............................................................24

7. Next steps – from planning to water delivery........................268. Partnerships.......................................................................289. Bibliography.......................................................................29

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List of FiguresFigure 1: The Namoi River Valley (Green et al. 2011)...........................................................8Figure 2: How inflows may vary and impact on water resource availability over the course of 2014–15 in the Namoi River Valley, from a starting point of low to high resource availability............................................................................................................13Figure 3: The annual management process for Commonwealth environmental water........27

List of TablesTable 1: Expected outcomes from the use of Commonwealth environmental water in the Namoi River Valley................................................................................................................6Table 2: Operational considerations for the Namoi River Valley in 2014–15.........................9Table 3: Commonwealth environmental water holdings in the Namoi River as at 30 April 2014...................................................................................................................................11Table 4: Summary of potential water use options for the Namoi River Valley in 2014-15...16Table 5: 2014–15 Basin annual environmental watering priorities for the Namoi River Valley..................................................................................................................................23

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1. BackgroundThis document is designed to be read in conjunction with the Commonwealth environmental water use options 2014–15: 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 Namoi River Valley this water 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 planning area and across the Murray-Darling Basin and having regard to the Murray-Darling Basin Authority’s Basin annual environmental watering priorities.

1.1. Demonstrating how Commonwealth environmental water in 2014–15 will contribute to the Basin Plan’s environmental watering plan objectives – Namoi River Valley

Commonwealth environmental water use options for the Namoi River Valley in 2014–15 include the following three flow types:

base flows (low flows)

freshes

bankfull.

These flow types are illustrated in Figure 4 of the document Commonwealth environmental water use options 2014–15: Planning approach.

Commonwealth environmental water delivery within the Namoi River Valley may be delivered to various parts of the river system including:

anabranches

small flood runners

and in-stream pool habitats.

The ecological response from delivering Commonwealth environmental water is reflected in the expected outcomes.

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. For further information please refer to The Environmental Water Outcomes Framework at www.environment.gov.au/water/cewo/publications/environmental-water-outcomes-framework.

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http://www.environment.gov.au/water/cewo/publications/environmental-water-outcomes-framework

http://www.environment.gov.au/water/cewo/publications/environmental-water-outcomes-framework

Table 1 shows the linkage between planned flow types and the expected outcomes for the Namoi River Valley. The table also links the short-term expected outcomes to a long-term contribution to the four Basin Plan objectives at the Basin scale (i.e. biodiversity, ecosystem function, resilience and water quality).

Table 1: Expected outcomes from the use of Commonwealth environmental water in the Namoi River Valley. Flow Type Expected outcomes

for 2014–15Contributions to longer term objectives

Contribution to the following Basin Plan objective

Base flows (low flows) Hydrological connectivity, including end of system flows

Connectivity Ecosystem Function

Individual survival and condition (individual refuges)

Population condition (individual refuges)

Resilience

Individual condition (ecosystem resistance)

Population condition (ecosystem recovery)

Resilience

Management of water quality issues (salinity, dissolved oxygen, pH and dissolved organic carbon)

Chemical Water Quality

Freshes and bankfull Vegetation condition and reproduction

Vegetation diversity Biodiversity

Vegetation germination and dispersal

Vegetation growth and survival

Biodiversity

Within ecosystem macroinvertebrate diversity

Macroinvertebrate diversity

Biodiversity

Fish condition Fish diversity Biodiversity

Fish reproduction, larval growth and survival

Larval and juvenile abundance

Biodiversity

Waterbird survival and condition

Waterbird diversity and population condition

Biodiversity

Other vertebrate reproduction, growth and survival

Adult abundance Biodiversity

Hydrological connectivity, including end of system flows


Mobilisation and dispersal of biotic and abiotic materials


Primary production, decomposition, nutrient and carbon cycling

Process Ecosystem Function

Individual condition (ecosystem resistance)

Population condition (ecosystem recovery)

Resilience

Management of water quality issues (salinity, dissolved oxygen, pH and dissolved organic carbon)

Chemical Water Quality

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2. Context for water use in 2014–15 in the Namoi River Valley

2.1. Delivering environmental water to the Namoi River Valley

The Namoi River Valley is located in north eastern New South Wales (NSW), extending westwards of Nundle to Walgett. Rainfall in the upper catchment drives valley flows, with water for regulated delivery throughout the valley being stored in Split Rock and Keepit dams. There are also a number of smaller regulating weirs downstream of Keepit Dam. At 845 km in length, the Namoi River is the primary riverine asset and constitutes a major tributary of the Barwon River. Major tributaries into the Namoi include Cox’s Creek and the Mooki, Manilla and the Peel rivers, which join the Namoi River upstream of Boggabri. Flows are confined in-channel until the floodplain begins to broaden at Gunnedah. The Pian (an anabranch of the Namoi River), Narrabri, Baradine and Bohena creeks contribute flows downstream of Boggabri.

The Peel River contributes an average annual volume of approximately 280 000 megalitres (ML) into the Namoi system (Green et al. 2011) and as such constitutes the other key asset within the Namoi River Valley. Flows are regulated out of Chaffey Dam and flow into the Namoi River slightly downstream of Keepit Dam. Major tributaries into the Peel River are Goonoo Goonoo Creek, Cockburn River and Dungowan Creek.

To date, opportunities to deliver environmental water into the Namoi River have been limited to baseflow and lower Namoi in-channel fresh requirements. Commonwealth environmental water is now held in the Peel. Should an action be triggered, anticipated outcomes include improved habitat condition for instream vegetation, fish, frogs and turtles.

Baseflows are in-channel flows, which can be satisfied through relatively low release rates from the relevant storage. Baseflows target nutrient cycling, fish passage and riparian health outcomes. 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. Environmental water is most likely to be undertaken in conjunction with a naturally occurring fresh flow trigger, or prolonged low flow conditions. In the Namoi River the 2013–14 water year experienced below average rainfall and above average temperatures. Whilst some rain was recorded, flows were generally unsuitable to trigger delivery of Commonwealth environmental water.

In order to achieve lower Namoi in-channel fresh requirements regulated releases from Keepit Dam can be timed to coincide with unregulated inflows from the Mooki River and Cox’s Creek. Benefits may also extend downstream to the Barwon-Darling. Consideration may also be given to augmenting modified river management practices that may be implemented by river operators in response to low inflows, such as block releases of consumptive water orders. Where possible, environmental water will be managed for the benefit multiple sites to maximise the efficiency and effectiveness of water delivery.

Held environmental water into the Peel River can be made available from Chaffey Dam in combination with downstream unregulated tributary inflows, or as a form of translucency release in response to storage inflows. Use of Commonwealth environmental water is not contingent on unregulated flows in the Peel River and can be delivered in conjunction with a stimulus flow managed by the NSW Office of Water under the existing environmental water plan.

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Figure 1: The Namoi River Valley (Green et al. 2011).

2.2. Operational and management considerations for 2014–15 in the Namoi River Valley

In the Namoi, the achievement of desired environmental outcomes for fresh flows will be closely related to the careful coordination of the timing of Commonwealth environmental water releases to coincide with existing unregulated flows in the Namoi River. When a low inflow scenario predominates, Commonwealth environmental water could be used in conjunction with minimum releases to provide low flow variability and protect water quality and drought refuge values.

In order to achieve desired environmental outcomes in the Peel River under a fresh flow scenario, Commonwealth environmental water delivery could be coordinated with the NSW stimulus flow. Alternatively, unregulated flows that originate from tributary inflows could be used to piggy-back releases from Chaffey Dam. To achieve environmental outcomes in the Peel under low inflow scenarios, Commonwealth environmental water could provide low flow variability for low base flows provided out of Chaffey Dam under the water sharing plan.

The lower Namoi entitlement has a maximum use in a single year of 125 per cent of entitlement (subject to the account balance) and 300 per cent of entitlement over three consecutive years. The Peel allocation cannot be carried over and unused water is forfeited.

Operational considerations such as delivery methods, opportunities, constraints and risks will differ depending on the inflow scenario and are summarised in Table 2. These considerations will be assessed throughout the year as decisions to make water available for use are made and implemented. This includes refining the ecological objectives, assessing operational feasibility and potential risks and the ongoing monitoring of the seasonal outlook and river conditions.

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Table 2: Operational considerations for the Namoi River Valley in 2014–15.Inflow scenario Very

lowLow Modera

teHigh Very

high

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, naturally occurring river flows and/or stimulus flow releases

Augment regulated flows to improve environmental outcomes.

End of system flows contribute to additional environmental outcomes in the Barwon-Darling system.

Constraints

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 entitlements is up to 125 per cent of entitlement.

Flow thresholds for existing river infrastructure may constrain the delivery of environmental water.

Risks*

The provision of Commonwealth environmental water must consider potential inundation impacts to property and infrastructure.

*See Section 7 for more information on risk management.

2.3. Valley condition

The MDBA’s 2012 Sustainable Rivers Audit report rated the river ecosystem health of the Namoi River Valley as poor. This was after eight consecutive years of below average flow from 2001 to 2009, combined with the existing effects of river regulation. While hydrology was considered good, macroinvertebrate communities and physical form rated as moderate, riparian vegetation and native fish communities were rated as very poor (Murray-Darling Basin Authority [MDBA] 2012b). Additional pressures from introduced species, as well as other factors such as increased fishing pressure and habitat

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degradation, have resulted in the population densities of native fish being significantly lower than historical levels (NSW Office of Water 2010).

The lack of high velocity flows in the Peel system has resulted in in-stream gravel becoming immobile and encrusted with filamentous algal mats and biofilms during summer (Foster 2004, Foster and Lewis 2009). As a consequence the river channel has narrowed and been invaded by riparian vegetation. In 2010–11, drought-breaking inflows commenced and flows across the valley continued into 2011–12. Consecutive years of widespread flooding and overbank flows contributed to significant longitudinal and lateral connection of river channel and fringing wetlands, which would have provided breeding and recruitment opportunities for aquatic species and contributed to condition improvements.

In the 2012–13 water year rainfall fell to below the historical average, providing the driest year since 2006. Regional differences meant that rainfall in the western part of the catchment was significantly lower than average, while above average rainfall was recorded in the catchment’s east, with December 2012 to March 2013 being consistently above average.

Of the three moderately high flow events, the first occurred in late July 2012, with approximately 30 000 ML/day passing Gunnedah and Mollee. Two smaller events occurred in late January and early March 2013, with maximum daily flows of approximately 22 000 and 17 000 ML respectively (Burrell et al. 2014). Late winter to early summer was particularly dry, and the warmest period on record for NSW occurred during July–October.

Some areas, such Lake Goran, an isolated ephemeral watersource near Gunnedah, retained water from the previously wet period and continued to provide drought refuge values into spring 2013. At least 27 ducks, colonial nesting waterbirds and shorebirds were recorded there in October 2013.

In March 2014, good rainfall occurred across much of NSW, with nearly 70 per cent of the state receiving above average rainfall. The good rainfall has been sporadic with the north west and far west receiving lighter, patchier falls. Combined with mild to warm temperatures, the rainfall boosted vegetation growth in some areas. As conditions are expected to continue to dry, water dependent species will continue to require support to ensure their survival over coming years and to continue to improve their condition and resilience to drought.

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3.Water availability3.1. Commonwealth environmental water holdings in the Namoi

River Valley for 2014–15

Commonwealth environmental water holdings available for use in 2014–15 in the Namoi River Valley are shown in Table 3 below.

Table 3: Commonwealth environmental water holdings in the Namoi River as at 31 May 2014.

Entitlement type

Entitlement held (GL)

Long-term average annual yield (GL)

Estimated carryover from 2013–14 (GL)

Forecast water availability for 2014–15 (GL)1

Upper Namoi (general security)

0.1 0.1 0 6–14(Up to 8.6 available for use within limits.)

Lower Namoi (general security)

6.9 5.3 6

Peel (general security)

1.1 0.2 N/A 0.1–0.6

Total 8.1 5.6 6Notes:1. Forecasts are based on the best available information including state forecasts and

historical inflow scenarios. Forecasts include carryover from 2013–14. Forecasts for regulated catchments are given to the nearest whole gigalitre except where the entitlement held by the Commonwealth is below 1 GL.

The full list of Commonwealth environmental water holdings can be found at www.environment.gov.au/topics/water/commonwealth-environmental-water-office/about-commonwealth-environmental-water/how-much and is updated monthly.

Portfolio management updates for the Commonwealth’s environmental water holdings are available at www.environment.gov.au/topics/water/commonwealth-environmental-water-office/portfolio-management/portfolio-management.

3.2. Other sources of environmental water allocations

There are currently no other sources of held environmental water in the Namoi River Valley.

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’).

The Bureau of Meteorology provides a seasonal streamflow forecasting service, which estimates the potential for low, median or high flows for the coming three months ahead.

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The Water Sharing Plan for the Upper Namoi and Lower Namoi Regulated Water Sources (2004) provides for planned environmental water and stock and domestic (replenishment flows) releases. Water deliveries to meet irrigation orders may provide baseflows in some sections of the Namoi River. Supplementing releases with Commonwealth environmental water may increase the potential for environmental objectives to be achieved and assist with delivery efficiency. The Peel Water Sharing plan has provision for a stimulus flow of 1 600 ML to be released under certain conditions. Once the capacity of Chaffey Dam has been increased the stimulus flow will be replaced by a 5 000 ML Environmental Contingency Allowance.

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4. Planning for water use in the Namoi River Valley in 2014–15

4.1. Planning for a range of inflows in 2014–15

In addition to influencing opportunities, constraints and risks in relation to environmental watering (see Table 2), 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) 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. The Bureau of Meteorology provides a quarterly seasonal streamflow forecasting service, which estimates the potential for low, median or high flows. As shown in Table 3, carryover from 2013–14 for the Namoi is likely to be approximately 6.1 GL, with forecast early season allocations (up to 31 July 2014), a total allocation range of approximately 6–7 GL is expected to be available for use in early 2014–15.

Consideration of this allocation range relative to the total entitlement volume (Table 3) and the full range of inflows that may be possible suggests that resource availability early in 2014–15 may be low to high, but not very low or very high. From this starting point, the full range of possible inflows suggests that resource availability over the course of the year could be between very low and very high (Figure 2). As such, the water use options described in Section 5 have been considered for the full range of resource availability. NSW State Water Corporation (NSW SWC) has advised that a Bulk Release delivery strategy will be applied in the Namoi River Valley for 2014–15. While the current resource availability has been assessed as moderate, some options developed for this scenario may not be pursued due to delivery constraints.

Figure 2: How inflows may vary and impact on water resource availability over the course of 2014–15 in the Namoi River Valley, from a starting point of low to high resource availability.

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4.2. Implementing watering actions throughout the year

Resource availability will change over the course of 2014–15 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 5 to be refined for implementation as required.

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5. Water use options for 2014–155.1. Summary of watering options

Watering options for 2014–15 for the Namoi and Peel rivers, 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 scaling of actions across potential very low to high inflow scenarios. This provides flexibility for water use to best complement natural inflows. Options have not been developed for very high inflow scenarios (and the relevant resource availability). During very high inflows, unregulated flows are likely to meet ecological objectives and (given the small quantity of holdings in the short-term) there is likely to be limited need for and effectiveness from deliveries of Commonwealth environmental water under this scenario.

Broadly, the aim of Commonwealth environmental watering in the Namoi and Peel rivers during 2014–15 will be to support in-stream outcomes, with a focus on the ongoing environmental recovery that commenced following the breaking of the drought (see Section 2.3).

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.

Feedback has been sought during the development of water use options for 2014–15 using existing state frameworks, for example, Environmental Water Advisory Groups and State Water Customer Service Committees. This feedback has been incorporated into the water use options where appropriate, particularly in relation to implementation risks and opportunities to improve outcomes through environmental water delivery.

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: [email protected].

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mailto:[email protected]

Table 4: Summary of potential water use options for the Namoi River Valley in 2014–15.

Applicable level(s) of resource availability

(see Section 4)Very Low Low Moderate High

Option 1 – Namoi River Fresh Flow

Option unlikely to be pursued under this

resource availability.

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 2 – Namoi River Base Flow

Contribute to base flow 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.


resource availability.

Option 3 – Peel River In-Stream Fresh Flow

Option unlikely to be pursued under this resource availability.

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 4 – Peel River Base Flow

Contribute to base flow 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.


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 and that constraints and/or risks may limit the ability to deliver environmental water.

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5.2. Assessment of environmental watering options


Catchment: Namoi

Complex: Namoi Catchment River Flows

Site: Lower Namoi River channel

Applicable level(s) of resource availability: Low to High

Relevant flow component: Base flows Fresh flows Bank-full flows Over-bank flows

Expected inundation extent: Floodplain inundation Wetland inundation

Summary of watering option: The purpose of the option is to enhance in-stream flows by contributing to rain

generated fresh flows or the delivery of other sources of water along the Namoi River to the end of the system. This will contribute to the health of in-stream habitat and water quality, as well as support ecological processes within the Namoi River. 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 body condition, growth and reproduction by providing increased food availability, improved opportunities for fish to access breeding habitat and to feed and shelter. Consideration will be given to augmenting other flows in the Namoi system (e.g. irrigation water deliveries).

The option has the potential to improve food web structure and habitat, benefitting 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.

To achieve this outcome, Commonwealth environmental water may contribute to unregulated fresh event(s) that exceed 4 500 ML/day at Narrabri or 1 800 ML/day downstream of Duncan’s Junction by maintaining flows for as long as possible with a managed rate of fall to baseflow rates. Should environmental water be used to augment other flows in the system flow rates would need to be determined based on the best information at the time of the release.

Timing Anytime (most likely late winter to summer)

Volume of Commonwealth environmental water

Up to 8.7 GL1 (depending on available allocation)

Action undertaken in this catchment previously:

Yes No

Similar action has been undertaken elsewhere in the Murray Darling Basin:

Yes No

1 Note: The Annual water use limit in the Namoi Water Sharing Plan is 125 per cent of entitlement. Actual water use will be based on the available water in accounts at the time up to the water use limit.

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Operational considerations and feasibility: Under natural conditions, rain generated fresh flows contribute to improvements in

ecological function within the Namoi River associated with carbon inputs from runoff and high flows inundating benches and connecting anabranches. Preference will be for Commonwealth environmental water to supplement natural flows rather than regulated releases.

Increasing the duration of unregulated freshes that exceed 1 800 ML/day downstream of Duncan’s Junction is likely to improve nutrient and carbon cycling and provide greater availability to habitat by wetting banks, benches and bars present in the lower Namoi River channel.

Consideration may be given to augmenting regulated releases to increase peak flows in the river and to provide a more natural recession rate.

Depending on the timing of the event, certain aquatic species will be advantaged according to their biological requirements and as conditions develop the flow regime and objectives targeted will be refined. Deliveries in August–September may contribute to pre-spawning migration opportunities. Deliveries during spring to summer may support reproduction cues or larval/juvenile dispersal.

Water orders will be developed in conjunction with NSW State Water Corporation (NSW SWC) to ensure operational feasibility and the achievement of environmental objectives.

Should special delivery arrangements be introduced in response to very dry conditions, such as the block release of irrigation orders, environmental water may be used to augment these releases to provide hydrological connectivity to the end of the system.

Consideration will also be given to coordinating delivery such that return flows are used to contribute to downstream outcomes, namely longitudinal connectivity (especially under very low to low resource availability where end of catchment discharge would otherwise be negligible).

Stakeholder feedback: No specific feedback received.

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Catchment: Namoi

Complex: Namoi Catchment River Flows

Site: Lower Namoi river channel

Applicable level(s) of resource availability: Very Low to Moderate



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.

The proposed option would occur after a protracted period of low flows to maintain essential refuge habitat for aquatic species.

To achieve this outcome, Commonwealth environmental water will contribute to low flow base flows at Bugilbone. The precise rate will be determined based on antecedent conditions and flows through the season. Commonwealth environmental water will be delivered as in-channel flows from Keepit Dam and managed within the normal water delivery arrangements.

Consideration may also be given to providing low flow base flows in the Manilla River below Split Rock Dam, if required, to maintain critical refuge. The Commonwealth holds 104 ML of General Security entitlement in the Upper Namoi River.

Timing Anytime in 2014–15


Up to 8.72 GL (depending on available allocation). (Up to 0.1 GL could be used in the upper Namoi River)


Yes No


Yes No

Operational considerations and feasibility: 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, improve water quality, and provide drought refuge for a range of aquatic species. The presence or absence of critical habitat or drought refuge habitat is the key factor influencing aquatic species.

This option could be delivered by supplementing other water sources, such as planned 2 Note: The Annual water use limit in the Namoi Water Sharing Plan is 125 per cent of entitlement. Actual water use will be based on the available water in accounts at the time up to the water use limit.

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environmental water or irrigation deliveries, to provide longitudinal hydrological connectivity and extend the duration of access to a range of habitats.

Should special delivery arrangements be introduced in response to very dry conditions, such as the block release of irrigation orders, environmental water may be used to augment these releases to provide hydrological connectivity to the end of the system.

Consideration will also be given to coordinating delivery such that return flows are used to contribute to downstream outcomes, namely longitudinal connectivity (especially under very low to low resource availability where end of catchment discharge would otherwise be negligible).

The Commonwealth holds 104 ML of General Security entitlement in the upper Namoi. Under an extreme dry scenario this small entitlement could be used in the Manilla River downstream of Split Rock Dam to flush and maintain critical refuge. o The effectiveness of such action may be limited by the volume of Commonwealth

environmental water held in the upper Namoi and the ability to release water from Split Rock Dam at low storage levels.

o The Commonwealth entitlement in the upper Namoi is not currently linked to any approved works. The entitlement will need to be linked to an existing works approval in the upper Namoi prior to it being used in this section of the system.

Stakeholder feedback: The Split Rock Water Users Association raised concerns that should Split Rock Dam be

drawn down to very low levels there may be a need to maintain connectivity and critical refuge in the Manilla River between Split Rock and Keepit Dams. The Office has incorporated this suggestion into the 2014–15 water use options.

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Catchment: Namoi

Complex: Other Namoi Catchment Sites

Site: Peel River

Applicable level(s) of resource availability: Moderate to High



Summary of watering option: The purpose of the option is to contribute to in-stream fresh flows to improve

ecological function, habitat condition and mobilise fine sediment. This will contribute to the structure of in-stream habitat, water quality and support ecological processes within the Peel River.

Connecting and extending the wetted period of habitat with the main channel will contribute to improvements in riparian vegetation condition and food production for the aquatic ecological community. The mobilisation of fine sediment below Chaffey Dam will improve stream substrate habitat condition for macro invertebrate communities.

Commonwealth environmental water would be released in conjunction with an in-stream fresh or other water sources, such as tributary flows or a Water Sharing Plan stimulus flow. Use of Commonwealth environmental water could contribute to the scouring of the river bed to remove periphyton and aquatic macrophytes and re-working the channel to improve in-stream habitat condition.

Timing Anytime (most likely late winter to summer)


Up to 1.1 GL (dependent on allocation announcements)


Yes No


Yes No

Operational considerations and feasibility: Water will be delivered into the Peel River via Chaffey Dam. The delivery arrangement

in this catchment involves water orders being submitted to NSW SWC by the Office. Water delivery will be undertaken by State Water Corporation.

The stimulus flow out of Chaffey Dam is only available when storage conditions are met. A stimulus flow may not be triggered in 2014–15. Should a stimulus flow not be triggered, releases will be timed to take advantage of other flows in the system, such as downstream tributary inflows or delivery/transfer of other sources of water.

Stakeholder feedback: Peel Valley Water Users Association raised concerns over flooding in the Peel Valley.

Prior to any watering action being approved the Office conducts a detailed assessment 21

of risk and measures that can be taken to minimise any risks.Option 4 – Peel River Base Flow

Catchment: Namoi

Complex: Other Namoi Catchment Sites

Site: Peel River

Applicable level(s) of resource availability: Very Low to Moderate



The purpose of the option is to provide low flow base flow variability to contribute to maintaining the ecological health and resilience of the Peel River system and 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.

The freshwater environment of the Peel Valley is comprised of a range of aquatic habitats, including extensive in-stream pool habitats, small flood runners, anabranches, benches, point gravel bars and terraces. The aquatic habitat in the Peel supports a diverse assembly of species, including threatened fish, frogs, and bird species.

The proposed option would occur after a protracted period of low flows to maintain essential refuge habitat for aquatic species.

To achieve this outcome, Commonwealth environmental water will contribute to low flow base flows below Chaffey Dam. The precise rate will be determined based on antecedent conditions and flows through the season.

Timing Anytime in 2014–15


Up to 1.1 GL (dependent on allocation announcements)


Yes No


Yes No

Operational considerations and feasibility: Water will be delivered into the Peel River via Chaffey Dam. The delivery arrangement in this catchment involves water orders being submitted to

NSW SWC by the Office. Water delivery will be undertaken by NSW SWC in accordance with its statutory requirements as a river operator.

Stakeholder feedback: No specific feedback received.

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5.3. Options contributing to the Basin Annual Environmental Watering Priorities

Each year the Murray-Darling Basin Authority develops Basin annual environmental watering priorities (‘Priorities’). All environmental watering in the Murray-Darling Basin, including the use of both held and planned environmental water, is to be undertaken having regard to the Priorities.

The Priorities are not an exhaustive list of all important assets and functions throughout the Basin and hence do not exclude other watering actions undertaken by environmental water holders and managers.

The 2014–15 Basin annual environmental watering priorities were published on 30 June 2014 and are available here: www.mdba.gov.au/what-we-do/environmental-water/environmental-watering-priorities/priorities-14-15. Table 5 identifies the relevant Priorities for the Namoi River Valley and the watering options that could contribute to achieving the identified outcomes.

Table 5: 2014–15 Basin annual environmental watering priorities for the Namoi River Valley

2014–15 Basin annual environmental watering priorities relevant to the Namoi River Valley

Watering options that may contribute to the achievement of priority outcomes

Theme: Enhance and protect refuge habitat

Native fish in the northern Basin: Improve survival of native fish populations by enhancing and protecting dry period refuge habitat in the northern Basin




Option 4 – Peel River Base Flow

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http://www.mdba.gov.au/what-we-do/environmental-water/environmental-watering-priorities/priorities-14-15

http://www.mdba.gov.au/what-we-do/environmental-water/environmental-watering-priorities/priorities-14-15

6. Accounting for the use of Commonwealth environmental water

6.1. Water use accounting

In the Namoi the Office is responsible for making arrangements to deliver environmental water with the river operator NSW SWC.

River flows will be accounted for at storages or at downstream flow gauges and will be reported to the Office by NSW SWC.

6.2. Monitoring

6.2.1. Operational monitoringOperational monitoring is monitoring that 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 Namoi River Valley, this includes NSW SWC, NSW Office of Water and NSW Department of Primary Industries.

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.

6.2.2. Long term intervention monitoringThe Long Term Intervention Monitoring Project (LTIM Project) is the primary means by which the Office will undertake monitoring and evaluation of the ecological outcomes of Commonwealth environmental watering. The LTIM Project will be implemented at seven Selected Areas over a five year period from 2014–15 to 2018–19 to deliver five high level outcomes (in order of priority):

1. evaluate the contribution of Commonwealth environmental watering to the objectives of the MDBA’s Environmental Watering Plan

2. evaluate the ecological outcomes of Commonwealth environmental watering at each of the seven Selected Areas

3. infer ecological outcomes of Commonwealth environmental watering in areas of the Murray-Darling Basin that are not monitored

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4. support the adaptive management of Commonwealth environmental water

5. monitor the ecological response to Commonwealth environmental watering at each of the seven Selected Areas.

This approach has a sound scientific basis that allows the Office to understand environmental outcomes in catchments where around 90 per cent of Commonwealth environmental water is held. A Monitoring and Evaluation Adviser will undertake evaluation at the Murray-Darling Basin scale.

The seven Selected Areas where monitoring will occur are:

1. Junction of the Warrego and Darling rivers

2. Gwydir River system

3. Lachlan River system

4. Murrumbidgee River system

5. Edward-Wakool River system

6. Goulburn River

7. Lower Murray River.

These areas were chosen to be representative of Commonwealth environmental watering across the Murray-Darling Basin.

The results from the LTIM Project can be used to infer ecological outcomes of Commonwealth environmental watering in the Namoi River Valley catchment.

Results from the LTIM Project will be published on the Office’s website and the data will be publicly available.

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7. Next steps – from planning to water delivery

Local knowledge and experience is critical to effectively manage and deliver Commonwealth environmental water. Stakeholders have an important role and provide critical information that informs each stage of the process for managing Commonwealth environmental water (see Figure 3).

The planning phase is the first stage in the cycle of environmental water management. The planning process occurs on an annual basis between January and the end of June, and each planning document represents the culmination of months of work and consultation. Throughout the planning process the Office consults closely with state environmental water managers, river operators and local environmental water advisory groups. The information gathered as part of the planning process feeds into the development of the options for the following water year.

Towards the beginning of the new water year the focus shifts from planning to implementation. Greater consideration is given to current and forecast catchment conditions and water availability to determine which of the options identified during the planning process can feasibly be implemented. Local on-ground knowledge is important for detailing a specific watering action including the flow magnitude, timing, triggers for commencement, rates of rise and fall and the area to be inundated. Once an action has been scoped in more detail an assessment against the following criteria is undertaken:

ecological value of the river, floodplain or wetland

expected outcomes from watering

potential risks of watering

long-term sustainability and management of the site

cost effectiveness and feasibility of watering.

Site managers and local community groups provide important information to inform these assessments. In particular, information related to potential risks provides critical input to the detailed risk assessment that is undertaken before a decision is made on a watering action. For further information see the Framework for Determining Commonwealth environmental water use (available at: www.environment.gov.au/topics/water/commonwealth-environmental-water-office/assessment-framework).

Following the scoping and assessment of potential watering actions, the Commonwealth Environmental Water Holder is required to make a decision on whether or not to commit the water and funds required to support the watering action. In doing so the Commonwealth Environmental Water Holder also has regard to the Basin Annual Priorities as required by the Basin Plan.

When a decision is made by the Commonwealth Environmental Water Holder to proceed with a watering action arrangements for implementation are made with delivery partners. This includes river operators, who manage the delivery of the water and operational monitoring. Local community involvement is crucial at this stage of implementation and during water delivery as conditions can change rapidly and may result in the need to adjust, suspend or even cancel the watering action.

Upon completion of the watering action, a review process, which generally takes place from March through to October, informs future watering actions and long-term

26

http://www.environment.gov.au/topics/water/commonwealth-environmental-water-office/assessment-framework).

http://www.environment.gov.au/topics/water/commonwealth-environmental-water-office/assessment-framework).

management. This review is informed by the weekly operational monitoring, results of ecological monitoring, and feedback provided by site managers and the local community.

Stakeholder input to CEWO required

Completion of all watering actions within a catchment –Watering Action Review

Ecological monitoring:• Short term ecological monitoring by other agencies• Long Term Intervention Monitoring

REVIEW

Mar

-O

ct 20

15

Detailed planning and scoping of feasible watering actions

Preparation of paperwork for decision includes assessment against criteria

Decision by C EWH

Implementation of watering action

Ongoing weekly operational monitoring

Watering action finished – acquittal report

Detailed risk assessment

IMPLEMENTATION

Change, suspend or cancel watering actions to reflect changing conditions

Jun 2

014-

Jun

2015

Approval of Water Use Options documents by CEWH

Assessment of catchment conditions

Annual planning for Commonwealth environmental water use options

PLANNING

Eliminate unrealistic/ unfeasible options

Jan–

Jun

2014

Figure 3: The annual management process for Commonwealth environmental water.

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8.PartnershipsThe Office has consulted with a range of stakeholders to develop the Commonwealth environmental water use options for the Namoi River Valley for 2014–15, including our delivery partners as follows:

Murray-Darling Basin Authority

New South Wales Office of Environment and Heritage

New South Wales Office of Water

New South Wales Department of Primary Industries

North West Local Land Services

State Water Corporation

Namoi Water.

The Office will continue to work with stakeholders and other interested community members in the planning, delivery, management and monitoring of Commonwealth environmental water.

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9. Bibliography

Alluvium (2010). Key ecosystem functions and their environmental water requirements. Report to the Murray-Darling Basin Authority, Canberra.

Banks, R.G. (1995). Soil Landscapes of the Curlewis 1:100 000 Sheet Report. Department of Conservation and Land Management, Sydney.

Barma Water Resources, Thurtell, L. and Wettin, P. (2012). Environmental Water Delivery: Namoi River. Prepared for Commonwealth Environmental Water, Department of Sustainability, Environment, Water, Population and Communities, Canberra.

Boys, C. Miles, N. and Rayner, T. (2009). Scoping options for the ecological assessment of cold water pollution mitigation downstream of Keepit Dam, Namoi River. MDBA Publication No. 20/09.Murray-Darling Basin Authority, Canberra.

Burrell M., Moss P., Petrovic J., Ali A., (2014) General Purpose Water Accounting Report 2012-2013: Namoi Catchment, NSW Department of Primary Industries, Sydney

CSIRO (2007). Water availability in the Namoi. Summary of a report to the Australian Government from the CSIRO Murray-Darling Basin Sustainable Yields Project, December 2007. CSIRO, Australia.

Davies, P.E., Harris, J.H., Hillman, T.J. and Walker, K.F. (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 Sustainability, Environment, Water, Population and Communities. Australian Wetlands Database: Directory of Important Wetlands. [online] available: www.environment.gov.au/topics/water/water-our-environment/wetlands/australian-wetlands-database/directory-important, accessed 19 August 2010.

Department of Sustainability, Environment, Water, Population and Communities (2011). Namoi Catchment description. Department of Sustainability, Environment, Water, Population and Community, Canberra.

Eco Logical Australia (2008). Namoi Wetland Assessment and Prioritisation Project. (Project No. 125-005) Draft report prepared for Namoi Catchment Management Authority, September 2008.

Eremaea Birdlines (2013). Interesting and unusual bird observations: Lake Goran. [online] available: www.eremaea.com/Lists.aspx?Context=Birdline&List=199891&Birdline=2 , accessed 15 May 2014.

Foster, N. (2004). Namoi River, evaluation of billabongs and anabranches - an assessment of relative lengths of billabongs potentially wetted during flow events of 4000-5000 ML/day. Unpublished report. Department of Infrastructure and Planning, Tamworth.

Foster, N and Lewis, A. (2009). Ecological Features of the Regulated Peel River. NSW Department of Water and Energy, Sydney.

Green, D. and Dunkerley, G. (1992). Wetlands of the Namoi Valley: Progress Report. Department of Water Resources, Technical Services Division, TS92.011, March 1992.

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http://www.environment.gov.au/topics/water/water-our-environment/wetlands/australian-wetlands-database/directory-important

http://www.environment.gov.au/topics/water/water-our-environment/wetlands/australian-wetlands-database/directory-important

Green, D., Petrovic, J., Moss, P. and Burrell, M. (2011). Water resources and management overview: Namoi catchment. NSW Office of Water, Sydney

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 (2012a). Assessment of environmental water requirements for the proposed Basin Plan: Lower Namoi River (in-channel flows). Licensed from the Murray–Darling Basin Authority, under a Creative Commons Attribution 3.0 Australia Licence.

Murray-Darling Basin Authority (2012b). Sustainable Rivers Audit 2: The ecological health of rivers in the Murray–Darling Basin at the end of the Millennium Drought (2008–2010). Summary. MDBA Publication 75/12. Murray-Darling Basin Authority, Canberra.

Namoi Catchment Management Authority (2006). Namoi Catchment Action Plan. Part B Natural Resource Management Plan. Namoi Catchment Management Authority, Gunnedah.

NSW Department of Primary Industries (2011). Key Fish Assets Namoi: Gunnedah-Wee Waa. NSW Department of Primary Industries (Fisheries).

NSW Department of Primary Industries (2012). Fish assemblages and spawning in the northern Murray Darling Basin: Effects of discharge and temperature in two regulated rivers. NSW Department of Primary Industries, Sydney.

NSW Department of Water and Energy (2008). Integrated Monitoring of Environmental Flows Wetting terrestrial organic matter: IMEF Phase 1, 1998-2005. Department of Water and Energy, Sydney.

NSW Scientific Committee (2004). Coolibah-Black Box Woodland of the northern riverine plains in the Darling Riverine Plains and Brigalow Belt South bioregions - Endangered ecological community determination. NSW Department of Environment and Conservation, Sydney.

NSW Office of Environment and Heritage (2006). Namoi River catchment map. [online] available: www.environment.nsw.gov.au/ieo/Namoi/map.htm, accessed 1 Jul 2012.

NSW Office of Water (2010). Water Sharing Plan for the Peel Valley regulated, unregulated, alluvial and fractured rock water sources: background document. June 2010.

Preece, R.M. and Jones, H.A. (2002). The effect of Keepit Dam on the temperature regime of the Namoi River, Australia. River Research and Applications, 18, pp. 397–414.

Sinclair Knight Merz (2009). Environmental Values and Watering Priorities for the Northern Murray Darling Basin. Report prepared for the Department of Environment, Water, Heritage and the Arts, Canberra.

Southwell, M.R. (2008). Floodplains as Dynamic Mosaics: Sediment and Nutrient patches in a Large Lowland Riverine Landscape. PhD Thesis, University of Canberra, Australia.

Thoms, M., Norris, R., Harris, J., Williams, D. and Cottingham, P. (1999). Environmental scan of the Namoi River Valley. Cooperative Research Centre for Freshwater Ecology. Prepared for the Department of Land and Water Conservation Namoi River Management Committee.

Webb, McKeown and Associates (2007). State of the Darling - Interim hydrology report. Murray-Darling Basin Commission Publication 07/07. Murray-Darling Basin Commission, Canberra.

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