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Commonwealth environmental water use options 2014–15:

Lachlan River Valley

Cover image credit: Moon Moon State Forest after delivery of environmental water in July 2013. Photo: Daniel Rothenfluh © CEWO.

This regionally significant wetland comprises river red gum, river cooba, which have iconic Aboriginal cultural values, as well as black box and western grey box and other species, which support waterbird breeding, fish and frogs.

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: Lachlan 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: Lachlan 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: Lachlan 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 –Lachlan River Valley.............................................................................................5

2. Context for water use in 2014–15 in the Lachlan River Valley. .82.1. Delivering environmental water to the Lachlan River Valley................................82.2. Operational and management considerations for 2014–15 in the Lachlan

River Valley........................................................................................................102.3. Valley condition..................................................................................................11

3. Water availability................................................................133.1. Commonwealth environmental water holdings in the Lachlan River Valley for

2014–15.............................................................................................................133.2. Other sources of environmental water allocations.............................................133.3. Natural or unregulated flows and planned environmental water........................14

4. Planning for water use in the Lachlan River Valley in 2014–15154.1. Planning for a range of inflows in 2014–15.........................................................154.2. Implementing watering actions throughout the year.........................................15

5. Water use options for 2014–15............................................165.1. Summary of watering options............................................................................165.2. Assessment of environmental watering options.................................................185.3. Options contributing to the Basin Annual Environmental Watering Priorities.....26

6. Accounting for the use of Commonwealth environmental water..........................................................................................27

6.1. Water use accounting........................................................................................276.2. Monitoring..........................................................................................................27

6.2.1. Operational monitoring.....................................................................................................27

6.2.2. Long term intervention monitoring..............................................................................27

7. Next steps – from planning to water delivery........................298. Partnerships.......................................................................319. Bibliography.......................................................................32

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List of FiguresFigure 1: Map of the Lachlan River Valley.............................................................................9Figure 2: Water resource availability and potential inflow scenarios for the Lachlan River

Valley over the course of 2014–15 from a starting point of low to moderate resource availability..............................................................................................15

Figure 3: The annual management process for Commonwealth environmental water........30

List of TablesTable 1: Expected outcomes from the use of Commonwealth environmental water in the Lachlan River Valley.......................................................................................................6Table 2: Operational considerations for the Lachlan River Valley in 2014–15.....................11Table 3: Commonwealth environmental water holdings in the Lachlan River Valley as at 31 May 2014.......................................................................................................................13Table 4: Other potential sources of environmental water in the Lachlan River Valley for 2014-15..............................................................................................................................13Table 5: Summary of potential water use options for the Lachlan River Valley in 2014–15....................................................................................................................................... 17Table 6: 2014–15 Basin annual environmental watering priorities for the Lachlan River Valley..................................................................................................................................26

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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 Lachlan 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 –Lachlan River Valley

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

base flows (low flows)

freshes

overbank flows - terminal wetland

discrete wetland and/or floodplain inundation.

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

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

effluent creek systems

terminal and fringing wetlands.

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.

Table 1 shows the linkage between planned flow types and the expected outcomes for the Lachlan River Valley. The table also links the short-term expected outcomes to a long-term

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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

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 Lachlan River Valley.

Flow Type Expected outcomes for 2014-15

Contributions to longer term outcomes

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 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

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 survival and condition (individual refuges)

Population condition (individual refuges)

Resilience



Resilience



Overbank flows - terminal wetland and discrete wetland and/or floodplain inundation

Vegetation condition and reproduction

Vegetation diversity Biodiversity

Vegetation germination and dispersal

Vegetation growth and survival

Biodiversity

Waterbird survival and condition

Waterbird diversity and population condition

Biodiversity

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Flow Type Expected outcomes for 2014-15

Contributions to longer term outcomes

Contribution to the following Basin Plan objective

Waterbird reproduction, recruitment and fledging

Waterbird diversity and population condition

Biodiversity

Hydrological connectivity, including end of system flows




Resilience



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

2.1. Delivering environmental water to the Lachlan River Valley

Flows in the Lachlan River Valley are driven by rainfall in the upper catchment. Water supplies are regulated by the headwater storage, Wyangala Dam (1 220 GL) and two mid river storages, Lake Cargelligo (36 GL) and Lake Brewster (154 GL) (Murray-Darling Basin Authority [MDBA] 2012a). There are three main tributary river systems that enter the Lachlan River below Wyangala Dam; the Boorowa, Belubula and Mandagery rivers. The upper reaches of the Belubula River is regulated by Carcoar Dam (35.8 GL). The Belubula River operates under its own Water Sharing Plan with end of system flows entering the Lachlan. Inflows from these three tributaries can be captured in Lake Cargelligo or Lake Brewster for consumptive and environmental use in the lower Lachlan River.

Strategic use of Lake Cargelligo and Lake Brewster, as mid-river storages, can reduce the travel times for water delivery to the lower reaches of the Lachlan River Valley making delivery more efficient. Bulk water transfers from Wyangala Dam to Lake Cargelligo and Lake Brewster also have the potential to provide additional environmental benefit to the mid Lachlan River.

Delivering water in the Lachlan River Valley is complex as it is a very long system with many meandering anabranches and effluent creeks that terminate in wetlands. Flow attenuation in the system is high and travel times for water are long due to the low gradient of the system. It can take up to 90 days for a flow from Wyangala Dam to reach the end of the system at Great Cumbung Swamp (Barma Water Resource Consulting [BWR] 2011).

As most of the assets targeted for environmental water delivery in the Lachlan catchment occur in the lower Lachlan floodplain it can be challenging for water managers when trying to deliver environmental water. Despite this, a large scale watering action implemented between June and July 2013 has proven very successful and resulted in a greater level of inundation in the lower Lachlan than originally anticipated. Wetlands in this area are both regionally significant and nationally important, providing valuable drought refuge, including for fish and frogs, and waterbird breeding habitats.

Environmental water delivery within the valley occurs in two main ways. During in-channel river flows, Commonwealth environmental water is gravity-fed or regulated using existing infrastructure into anabranches, creeks and wetlands. During high river flows water passes over bank into floodplain and wetland sites. Where possible, environmental water will be managed to benefit multiple sites en route to maximise the efficiency and effectiveness of water delivery.

The Water Sharing Plan for the Lachlan Regulated River Water Source (2004) provides for planned environmental water and replenishment flow releases (including flows for stock and domestic use). Commonwealth environmental water can be piggy-backed onto these river flows and increase the potential for environmental objectives to be achieved and assist with delivery efficiency. More information regarding the water sharing plan can be found on the New South Wales (NSW) Office of Water’s website.

More information on the Lachlan catchment’s wetland assets and the Lachlan Riverine Environmental Water Management Plan, which informs the use of NSW planned and held environmental water, can be found at the Lachlan Riverine Working Group’s website.

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Figure 1: Map of the Lachlan River Valley.9

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

The delivery of environmental water in the Lachlan River Valley is currently constrained by the release capacities from storages, channel capacities, low lying floodplain areas and effluent creek systems. Watering options will be developed in consideration of the following constraints:

Lake Brewster release capacity – a maximum of 3 000 ML/day

Willandra Weir – flows above 2 400 ML/day in the Lachlan River upstream of Willandra Weir commence flows into Willandra Creek

risks to private infrastructure – delivering flows exceeding approximately 2 800 ML/day at Hillston could require some private irrigation pumping infrastructure to be temporarily relocated to avoid inundation.

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.

Under very low and low inflow scenarios, river operations may be adjusted to minimise system losses. This may provide an opportunity to use environmental water along with deliveries of consumptive water to achieve multiple outcomes. However, it is possible that river management under these conditions may compromise the feasibility or viability of some watering actions. Under these circumstances it will be important to work closely with delivery partners to maximise the environmental benefit from the watering actions undertaken.

The high rainfall and increased stream flows combined with warmer winter and spring temperatures has resulted in strong in-channel vegetation growth in some effluent creeks. While these creeks are assets in themselves, they are also integral to the delivery of water to key wetland assets. In-channel vegetation growth can impede water flows into these assets.

Environmental water may be made available for some watering options from NSW Office of Environment and Heritage (NSW OEH) either as adaptive environmental water or discretionary planned environmental water. In these circumstances all sources of environmental water will be coordinated between NSW OEH and the Office to maximise the environmental benefit.

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Table 2: Operational considerations for the Lachlan River Valley in 2014–15.

Inflow scenario Very low

Low Moderate

High Very high

Opportunities

Manage the recession of naturally occurring high flows to provide for a more natural flow pattern.

Use environmental water in conjunction with, or to maximise the environmental benefit of, naturally occurring tributary and/or river flows. Use environmental water to maintain base flows and provide freshes to support ecological improvements and refuge sites in effluent creek systems.Use environmental water to support bird breeding events and aquatic species propagation/breeding requirementsUse environmental water to complement river operations (e.g. bulk transfers between storages or replenishment flows) to achieve improved environmental outcomes in the mid-Lachlan and effluent creek systems.Constraints River operations under very dry and dry conditions may limit options for use of available 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.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. Potential impacts on private infrastructure requiring relocation of pumps etc

* See Section 7 for more information on risk management.

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2.3. Valley condition

Between 2000 and 2010 the Lachlan River Valley 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. Some moderate inflows occurred during this period in 2001–02 and 2005–06, but drought breaking inflows were experienced in 2010–11 with further high inflows experienced across the valley in 2011–12, particularly during February to March (Burrell et al. 2012). These flows inundated large areas of floodplain wetland with some areas for the first time in a decade (Lachlan Riverine Working Group [LRWG] 2013). Areas such as Lake Bullogal, Ryan’s Lake and Lake Ita in the lower part of the system received inflows for the first time since 1990 (BWR 2011). The 2012–13 water year saw a return to drier than average conditions in the Lachlan River Valley with rainfall across the catchment and subsequent dam inflows significantly below average (Burrell et al. 2012). This trend has continued throughout the 2013–14 water year.

The MDBA’s second Sustainable Rivers Audit report (based on data collected from 2008 to 2010) concluded that the Lachlan River Valley was in very poor river ecosystem health. While the Lachlan River Valley was recognised as having good physical form and moderate macroinvertebrate communities and hydrology, the valley was rated as poor for riparian vegetation and extremely poor for native fish communities (MBDA 2012b).

Most areas within the Lachlan River Valley are in various stages of recovery. This recovery is evidenced by a large bird breeding event in 2010–11 at key locations such as Booligal Wetlands, Merrowie Creek and Lake Brewster (NSW Office of Environment and Heritage [OEH] 2012a). Further evidence is the regeneration of river red gums and vigorous growth of lignum and reed beds across the Lachlan system, especially at Murrumbugil Swamp and Lake Ita (NSW OEH 2012b).

Between June and July 2013 nearly 89 GL of environmental water was delivered, to wetlands downstream of Lake Brewster. The Office provided almost 74 GL and NSW contributed 15 GL. The purpose of the watering action was to support ongoing recovery following the 2012 floods and contribute to improved vegetation condition, recruitment and extent, as well as hydrological connectivity and biotic dispersal. Flows continued running into the Great Cumbung Swamp until late August 2013. Reports from landholders and NSW OEH indicate that the vegetation response from the flow is persisting despite the recent dry conditions.

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

River Valley for 2014–15

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

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

Entitlement type

Entitlement held (GL)

Long-term average

annual yield (GL)

Expected carryover

from 2013–14 (GL)1

Forecast water

availability for 2014–15 (GL)2

Lachlan (high security)

0.9 0.9 0 44–131(Up to 87.8 available within use limits.)

Lachlan (general security)

86.9 36.5 44

Total 87.9 37.4 44

Notes:1. Future decisions about use, transfers and the ability to deliver already approved actions will

affect expected carryover from 2013–14. 2. Forecasts are based on the best available information including State forecasts and historical

inflow scenarios. Forecasts include carryover from 2014–15 and are given to the nearest whole gigalitre.

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

Other sources of environmental water that may be used to complement Commonwealth environmental water delivery in the Lachlan River include water held by NSW OEH. Table 4 below outlines the different environmental water entitlements held by other water holders.

Table 4: Other potential sources of environmental water in the Lachlan River Valley for 2014–15.

Source Management Authority

Entitlement

NSW Environmental Water Holdings1 NSW OEH

High Security 1 000 MLGeneral Security 24 569 MLUnregulated 184 ML

Lake Brewster Adaptive NSW OEH 12 000 ML

1 NSW environmental Water holdings - http://www.environment.nsw.gov.au/environmentalwater/waterpurchase.htm13

Environmental Water Licence2

3.3. Natural or unregulated flows and planned environmental water

In addition to water entitlements held by environmental water holders, 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 Water Sharing Plan includes two Environmental Contingency Allowances of 10 000 ML each and a Water Quality Allowance of 20 000 ML. The Water Quality Allowance is set aside each year in full for use to manage water quality issues, particularly salinity. The full volume for the two Environmental Contingency Allowances is allocated if general security water accounts hold 50 per cent of entitlement at 1 July. Otherwise allocations are not made until General Security accounts reach 75 per cent of entitlement.

Translucent releases from Wyangala Dam are provided for under the Lachlan water sharing plan and are managed by NSW State Water Corporation (NSW SWC). Triggers for translucency flows are based on inflows into Wyangala Dam.

For more information on the operation of water sharing plan planned environmental water please refer to the NSW Office of Water’s website.

Three major tributaries enter the Lachlan downstream of Wyangala Dam, the Boorowa, Belubula and Mandagery rivers. These tributaries sometimes provide unregulated flows to the Lachlan River. However, under current practices NSW SWC is required to use the flows to fill water orders in the system or reregulate the water to the extent possible in Lake Cargelligo and Lake Brewster. Options may be available to use held environmental water to compensate for lost reregulation capacity to maintain flow integrity past mid-river storages.

The Water Sharing Plan makes allowance for replenishment flows to effluent creek systems within the Lachlan River Valley. While these replenishment flows are not considered planned environmental water, they do present opportunities to piggy- back environmental water to enhance environmental outcomes in these systems. These allowances include:

up to 12 000 ML per year to Willandra Creek, including Morrison’s Lake

up to 9 000 ML per year to the Marrowie Creek

up to 9 000 ML per year to the Torrigany, Muggabah and Merrimajeel creeks

up to 12 000 ML per year to provide a continuous supply to Booberoi Creek, at its off-take, at a rate sufficient to provide for town, domestic and stock needs and to provide for a visible flow at the Ginniguldrie Road Bridge.

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.

2 This entitlement is held by the Commonwealth and managed by NSW OEH14

4. Planning for water use in the Lachlan 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) and other environmental water holders (Section 3.2) 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 3, carryover from 2013–14 for the Lachlan is likely to be approximately 44 GL. Forecast early season allocations (up to 31 July 2014), including carryover, are likely to be low.

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 moderate. 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 developed for the full range of resource availability.

Figure 2: Water resource availability and potential inflow scenarios for the Lachlan River Valley over the course of 2014–15 from a starting point of low to moderate resource availability.

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

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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

The following section details potential watering options for 2014–15 for the Lachlan River Valley, 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 scaling of actions across several potential inflow scenarios. This provides flexibility for water use to best complement natural inflows. Options have not been developed for a very high resource availability in recognition that at these times, large areas of the Lachlan River Valley would likely be experiencing flooding. Such flooding would achieve many environmental outcomes and provision of additional environmental water would likely cause adverse third party impacts.

Broadly, the aim of Commonwealth environmental watering in the Lachlan River Valley during 2014–15 will be to consolidate and protect the ongoing environmental recovery over the last three years through a potentially low rainfall and inflow period. Watering options aim to support threatened species and vegetation ensuring their survival. For some parts of the system, this will mean providing river flows to support wetland and in-stream refugia for aquatic fauna.

Watering options have been designed to specifically enable the scaling of actions across several potential unregulated inflow scenarios. This provides flexibility for water use to best complement unregulated inflows and support the natural inundation of floodplains and wetlands. The provision of Commonwealth environmental water in combination with small to moderate unregulated freshes would promote connectivity between wetlands and support vegetation recovery and growth. If conditions improve, environmental water may contribute to recruitment opportunities for a range of waterbird and native aquatic species (e.g. fish, frogs, turtles, invertebrates), which only reproduce in response to specific environmental triggers, for example, rising or falling water levels in particular seasons. Where possible, environmental water will be managed to benefit multiple sites en route to maximise the efficiency and effectiveness of water delivery.

Where required, regulated environmental water deliveries will typically seek to enhance low to medium in-channel river flows and support the hydrological requirements of key wetland plant species that occur in the low lying areas of the wetlands. Wetland vegetation provides valuable breeding habitat for waterbirds and other fauna. River flows will also seek to provide for in-stream refuge sites during periods of extended low or no flow. 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.

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

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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 5: Summary of potential water use options for the Lachlan River Valley in 2014–15

Applicable level(s) of resource availability(see Section 4)

Very Low Low Moderate High

Option 1 – Effluent creek system refresh

Merrimajeel Creek (Murrumbidgil Swamp), Muggabah Creek (Lower Gum Swamp), Merrowie

Creek and Willandra Creek

Contribute to low flows to support drought refuge and water quality.

Contribute to flows to support in-stream habitat, wetland vegetation recruitment and extent.

Option 2 – Water Bird Reproduction and Fledging

Contingencies

Option unlikely to be pursued under this

resource availability.Contribute to fresh flows to support waterbird reproduction and fledging, if

required.

Option 3 – Lachlan Swamps,Moon, Moon Swamp and Great Cumbung Swamp

Option unlikely to be pursued under this resource availability.

Subject to translucency/water trigger and allocation, augment/extend fresh flows or overbank flows from winter to spring to improve vegetation condition and

maintain resilience.Option 4 – Fish contingency (within Lachlan catchment)

Option unlikely to be pursued under this

resource availability.Contribute to variable river flows (including freshes) to maintain water levels in

reaches with identified fish reproduction and drought refuge values.Note: Under certain resource availabilities, options may not be 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: Lachlan

Complex: Effluent Creek System

Sites: Effluent creeks and associated wetlands in the Lower Lachlan system - Merrimajeel Creek (Murrumbidgil Swamp), Merrowie Creek, Muggabah Creek (Lower Gum Swamp) and Willandra Creek.

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

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

Expected inundation extent: Floodplain inundation Wetland inundation

Summary of watering option: The overarching purpose of the option is to provide flows into priority effluent creek

systems to consolidate the benefits of inundation provided from 2011–12 to winter 2013. This will be undertaken using a prioritised approach according to environment watering need and resource availability scenario.

The first priority is the Merrimajeel Creek system, targeting Murrumbigil Swamp, particularly under very low and low resource availability scenarios. This will be followed by Merrowie Creek and then other effluent creek systems, based on the ecological need and resource availability. The extent to which other systems apart from Merrimajeel Creek are considered will be based on improvements in resource availability and available environmental water. Volumes will depend on the needs of individual sites.

The action will support the survival and growth of river red gums, and will improve lignum and other wetland vegetation values for waterbirds, and maintain frog habitat. Recently, the southern bell frog was recorded at several sites in the lower Lachlan system.

Timing June – November (November most favourable)

Volume of Commonwealth environmental water

Up to 30 GL, subject to need and resource availability.

Action undertaken in this catchment previously:

Yes No

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

Yes No

Operational considerations and feasibility: This option will be coordinated with NSW OEH to ensure complementary delivery. NSW

OEH manages held and planned environmental water for NSW (including the ecological contingency allowances).

Environmental water is expected to be delivered from Lake Brewster to the target area in the lower Lachlan system. Flows will then be gravity fed to the target site.

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Where practicable Commonwealth environmental water will be delivered in conjunction with a replenishment flow or natural event.

Should other flows (e.g. water sharing plan replenishment flows) be deemed to support the environmental needs of a priority effluent creek system then another creek system within the lower Lachlan will be considered for environmental water delivery. Re-prioritisation will be based on environmental need and resource availability.

Stakeholder feedback: Stakeholders noted that late summer rainfall in parts of the system has resulted in

strong vegetation growth in some channels. This may impede efficient delivery of flows into Muggabah and Merrimajeel creeks.

There are varying conditions and ecological requirements across the system. Concerns were raised by members of the Lachlan Riverine Working Group around the potential for replenishment and other flows to trigger breeding of colonially nesting waterbirds that may not be able to be supported under the current conditions.o Option 2 provides for a wetland waterbird breeding and fledging contingency.o The success of any waterbird breeding event may be dependent on available food

sources for nesting waterbirds.

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Option 2 - Water Bird Reproduction and Fledging Contingencies

Catchment: Lachlan

Complex: Booligal Wetlands and other Lachlan sites

Site: Most likely Booligal Wetlands and / or Merrowie Creek

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



Summary of watering option: The wetlands in the lower Lachlan system are known to support large waterbird

reproduction events, in particular of colonial nesting species (egrets, herons, ibis and spoonbills). These species provide a good indicator of catchment hydrological condition and wetland health, and are particularly sensitive to fluctuations in water level as a result of extraction.

The purpose of this option is to support waterbird reproduction, including colonial nesting waterbirds. In the event of a colonial nesting waterbird reproduction event commencing, where system inflows are lower than expected, and/or water levels are at risk of dropping, additional environmental water may be required to ensure that conditions persist to support nesting and fledging of chicks.

Areas likely to require water to support colonial waterbird reproduction events are the Booligal Wetlands and Merrowie Creek (to Cuba Dam), where nearly 75 000 pairs of ibis successfully bred in 2010–11. The location for this option will become more apparent should breeding commence.

The final decision on the implementation of this waterbird contingency option will be based on the apparent size of the breeding event, feasibility of delivering environmental water to the site within the required timeframe, the time of year, the overall condition of the site (nesting material and food sources) and any other factors that may affect the success of the breeding or survival of chicks. There may be times and/or conditions when it is not possible or appropriate to use environmental water in this manner.

Timing As required, most likely between September and January.


Up to 20 GL


Yes No


Yes No



The volume and delivery pattern will be highly dependent on the location of the waterbird reproduction event and the degree to which it requires support from

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environmental water. Environmental water is expected to be delivered from Lake Brewster to the target area

in the lower Lachlan system. Flows will then be gravity fed to the target site. This option may not be required if other flows (e.g. unregulated flows or water sharing

plan replenishment flows) are deemed sufficient to support the breeding to completion. This option may also depend on the likelihood of high winter to spring rainfall in the catchment.

Stakeholder feedback: Members of the Lachlan Riverine Working Group noted that given the drier conditions a

good food supply may be available for ibis in the lower Lachlan. Should adequate flows commence in spring an ibis response may be triggered.o The Office notes that an adequate food source in the area may be a key to the

success, or otherwise, of a breeding event for colonial nesting birds, including Ibis. Such information is taken into account on whether to proceed or not proceed with a watering action.

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Option 3 - Lachlan Swamps, Moon, Moon Swamp and Great Cumbung Swamp

Catchment: Lachlan

Complex: Lachlan River and Fringing Wetlands

Site: Moon Moon and Peppermint Swamp, Lake Waljeers, Lake Itta and Great Cumbung Swamp

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



Summary of watering option: Moon Moon Swamp filled as a result of natural inflows in late 2010. Environmental water

was delivered in 2013 as part of a larger watering action in the lower Lachlan. 2013–14 saw a return to drier conditions in the Lachlan catchment.

Due to the dry conditions experienced in 2013–14, environmental flows may be required to maintain parts of the Lachlan River and its associated wetland areas that received environmental water during 2012–14, such as Moon Moon Swamp.

The purpose of this option is to refresh hydrological connectivity and drought refuges in the lower reaches of the Lachlan River that benefitted from previous environmental water deliveries.

This action would be triggered by additional water in the system (e.g. through translucency releases or unregulated tributary flows).

Timing From July 2014 to June 2015Volume of Commonwealth environmental water

Up to 20 GL


Yes No


Yes No



Commonwealth environmental water would be delivered from Lake Brewster and contribute to flows of up to 2 000 ML/day at Whealbah for up to 30 days, most likely in late winter to spring.

Effective delivery of this option is contingent on the following arrangements being in place:o Water management by NSW SWC is such that the water order can be delivered to

the lower reaches of the river, that is, adequate volumes in Lake Brewster or in the river system to meet the order. Additional water may need to be transferred from Wyangala Dam to meet the volume of this order.

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o The minimisation of flows to non target areas (e.g. Willandra, Muggabah, Merrimajeel and Torriganny Creek) through the use of water management infrastructure.

o Accounting points and arrangements for losses to non target areas (e.g. Willandra Creek) agreed with NSW SWC.

Stakeholder feedback: No specific feedback received.

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Option 4 – Fish contingency (within Lachlan catchment).

Catchment: Lachlan

Complex: Lachlan River

Site: Lachlan River

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



Summary of watering option: The Lachlan River is part of an endangered ecological community under NSW Fisheries

Management Act 1994 and has been impacted by regulated river conditions and invasive species. The system is known to support several fish species, some of which are listed under the Environmental Protection Biodiversity and Conservation Act 1999 and relevant state legislation. These include Murray cod and freshwater catfish.

This option aims to target reaches in the Lachlan River that have good riparian vegetation, moderate to high snag load and high quality refuge habitat. This option is expected to contribute to habitat access, fish condition, spawning and larval survival.

Commonwealth environmental water has been used to contribute to outcomes for native fish at a number of sites in the Murray-Darling Basin, including the Edward-Wakool system, Goulburn, Murrumbidgee, Namoi, and Gwydir rivers, and Border Rivers. These actions have generated knowledge that can also be used in other catchments, and can be used to reduce advantages for invasive species that some regulated water delivery for consumptive purposes create.

This option will augment tributary inflows in the mid Lachlan River (Boorowa River, Belubula River and Mandagery Creek) with environmental water from Wyangala Dam (and Lake Brewster if required) to provide flow integrity from the mid Lachlan River to the lower Lachlan River below Lake Brewster. Temperature thresholds will also be important as an event trigger.

Consideration will also be given to underwriting system losses as a result of modifying regulated flows, including for consumptive purposes or water transfers between storages, where these modifications provide a clear benefit to native fish; or delivery to fringing wetlands and/or anabranch systems for the benefit of small bodied native fish

Other options may include delivering a flow pulse at a time, location and duration known to benefit native fish, modifying transfers (required for consumptive purposes) to create variability aimed at providing benefit for native fish.

This option will be further refined in consultation with NSW DPI (Fisheries), NSW SWC, NSW OEH and NSW Office of Water.

Timing Spring to autumn as required


Up to 20 GL

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Yes No


Yes No

Operational considerations and feasibility: The Office will work with relevant NSW Government agencies, including NSW DPI

(Fisheries), to refine the triggers, flow rates and logistics of this action. The operational management of this option will be coordinated with NSW SWC as river

managers and NSW OEH to ensure complementary delivery of NSW and Commonwealth environmental water.

Triggers for this action may consist of a combination of tributary inflows and suitable water temperature thresholds.

Consideration will also be given to underwriting system losses as a result of modifying regulated flows, including water transfers between storages, where these modifications provide a clear benefit to native fish and are allowable under the Water Sharing Plan.

Stakeholder feedback: The Lachlan Riverine Working Group noted that the aim should focus on protecting a

proportion of small to medium natural flows to retain the natural ‘chemical’ signal and provide flow integrity through the system. Where necessary flows can be mixed with stored water to improve outcomes.

It was suggested that water from Lake Brewster could be used to provide additional water in the lower Lachlan due to it potentially having a different chemical signal to water from Wyangala Dam. The chemical makeup of Brewster water unknown.

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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 6 identifies the relevant Priorities for the Lachlan River Valley and the watering options that could contribute to achieving the identified outcomes.

Table 6: 2014–15 Basin annual environmental watering priorities for the Lachlan River Valley

2014–15 Basin annual environmental watering priorities relevant to the Lachlan 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 3 – Lachlan Swamps

Option 4 – Fish contingency

Waterbird Refuge: Maintain waterbird habitat, including refuge sites, and food sources, to support waterbird populations across the Murray-Darling Basin. Support waterbird breeding, where feasible


Option 2 – Water Bird Reproduction and Fledging Contingencies

Option 3 – Lachlan Swamps

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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

Across NSW Commonwealth environment water is generally transferred to NSW OEH’s accounts. NSW OEH is then responsible for making arrangements to deliver the environment water with river operators such as NSW SWC. In some instances, water may be delivered without trade to NSW OEH environmental accounts.

River flows will be accounted for at storages or at downstream flow gauges and will be reported to the Office by NSW OEH. Where applicable, water delivered to individual wetland sites will be accounted at flow gauges or metered pumps at those sites.

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 Lachlan River Valley, this includes the NSW OEH, NSW State Water Corporation, and NSW Office of Water.

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.

A Monitoring and Evaluation Plan that captures the long term arrangements between scientific organisations and delivery partners has been developed for the Lachlan River system Selected Area.

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.

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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).

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 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 CEWH

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 Lachlan River Valley for 2014–15, including our delivery partners as follows:

Murray-Darling Basin Authority

NSW Office of Environment and Heritage

NSW Office of Water

NSW Department of Primary Industries

Central Tablelands and the Central West Local Land Services.

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. BibliographyBarma Water Resource Consulting (2011). Environmental Water Delivery – Lachlan River. Department of Sustainability, Environment, Water Populations and Communities, Canberra.

Burrell M., Moss P., Nguyen K., Petrovic J., Ali A., (2012). General Purpose Water Accounting Report 2011-2012: Lachlan/Belubula Catchments. NSW Department of Primary Industries, Sydney.

Hamilton, S. K., Bunn, S. E., Thoms, M. C. and Marshall, J. C. (2005). Persistence of aquatic refugia between flow pulses in a dryland river system (Cooper Creek, Australia). Limnology and Oceanography, 50, pp. 743-754.

Lachlan Riverine Working Group (2013). Lachlan Environmental Water Management Plan. [online] available: www.lrwg.com.au/, accessed 8 March 2013.

Murray-Darling Basin Authority (2012a). Assessment of environmental water requirements for the proposed Basin Plan: Booligal Wetlands. Licensed from the Murray-Darling Basin Authority, under a Creative Commons Attribution 3.0 Australia Licence. MDBA Publication No: 37/12.

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.

NSW Department of Primary Industries (2006). Reducing Impacts of Weirs on Aquatic Habitat – New South Wales detailed weir review. Lachlan CMA region. Report to the New South Wales Environmental Trust. NSW Department of Primary Industries, Flemington, NSW.

NSW Office of Environment and Heritage (2013). Environmental Water Use in NSW – Annual Report. Office of Environment and Heritage, Sydney.

NSW Office of Environment and Heritage (2012a). Environmental Water Use in NSW – Annual Report. Office of Environment and Heritage, Sydney.

NSW Office of Environment and Heritage (2012b). Annual Environmental Watering Plan 2012–13 - Lachlan Valley. NSW Office of Environment and Heritage, Sydney.

Price, A. (2009). Distrubtuion and Recruitment Patterns of Fish in the Lower Lachlan River. Final report prepared for the Lachlan Catchment Management Authority by the Murray-Darling Freshwater Research Centre, MDFRC Publication 17/2010.

Wallace, T. and Bindokas, J. (2011). The impact of drought on water quality and fish communities within refuge pools in the Lachlan River. Final Report prepared for the Lachlan Catchment Management Authority by the Murray Darling Freshwater Research Centre MDFRC Publication 20/2011.

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http://www.lrwg.com.au/

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