Environmental Flows Assessment Program (EFAP)

The Environmental Flows Assessment Program (EFAP) provides the science to inform an assessment of how effective rules and strategies within Queensland Water Plans (WPs) support ecological outcomes.

WPs manage the allocation and sharing of water in catchments throughout Queensland to achieve an appropriate balance between human consumptive needs and flows that support environmental values. To guide the sustainable management of water, each WP specifies general and ecological outcomes that the plan seeks to achieve. For example, the Mary River Basin WP requires flows to be managed in a way that minimises impacts on the Mary River cod, the Mary River turtle and the Australian lungfish.

Provision of water for the environment is important to support ecosystem health and ecosystem services which in turn helps support healthy communities and a functional working river. EFAP monitors selected ‘ecological assets’ through targeted monitoring projects. Ecological assets are components of an ecosystem and could include species, places, or natural processes. Ecological assets are selected for WP monitoring on the basis that they have a known, critical link to certain flows.

To measure a WP’s performance in achieving its stated ecological outcomes, EFAP uses an ecohydrological approach to assess the risk to ‘ecological assets’[1]. Ecological assets are: (i) indicators and representative of a broader set of the ecological values of an area, (ii) critically-linked to (i.e., dependent upon) one or more aspects of the flow regime (i.e., magnitude, duration, frequency, timing, rate of change, etc.) in order to maintain their long-term viability, and (iii) potentially sensitive to the types of water management and the range of flow regime alterations from water management in the water plan catchment. Ecological assets are selected for WP monitoring on the basis that they have a known, critical link to certain flows. For example, if a fish species requires a flooding event of a certain magnitude to trigger spawning and recruitment, and this event does not occur, the fish population may decline over time.

As WPs only manage the flow regime through the capture and take of water, the influence of flow on ecosystems must be separated from the influence of other environmental stressors. The monitoring approach of EFAP is based on the following principles[2]:

• Ecosystem condition is influenced by a range of factors, and flow is only one of these factors.
• Ecosystem components respond to the local hydraulic habitat conditions (for example, depth, velocity, water quality) where flow interacts with river morphology and other features.
• The flow requirements of specific ecosystem components can be used as indicators of the broader ecosystem.

The EFAP is project based. For example, information was collected on the location and inundation height of nests of the white throated snapping turtle over several seasons in the Burnett WP area. This information was used in the review of the WP and new operating rules were recommended to reduce nest inundation and provide better overall outcomes for water users.

EFAP research and monitoring contributes to a growing knowledge base of best available science. This information is used to continually improve water resource planning.

The EFAP is a quantitative modelling approach that evaluates the probability that adverse effects may occur as a result of a modified flow regime. It uses a flexible, risk-based ecohydrological approach that draws on existing information and knowledge of the ecological values of the catchments as well as relevant flow-ecology information in the broader scientific domain in six steps:

1. Identifying ecological assets through comprehensive reviews of the scientific literature, information in technical reports, guidelines, action plans, regional ecosystem mapping, government databases, and extensive consultation with relevant local experts and stakeholders. Ecological assets are a sub-set of the water-dependent ecosystem components (e.g., species, populations) and functions (e.g., processes) within an area being assessed.

2. Defining ecohydrological rules and habitat provision and associated water quality attributes through receptor conceptual models that show the flow-related influences on the properties of the assessment endpoints. Ecohydrological rules are a flow-dependency conceptualisation, which represents its critical links to flow (e.g. discrete aspects of the flow regime (i.e., location, timing, frequency, magnitude, duration).

3. Defining assessment endpoints of the entity (valued aspect of the ecosystem—i.e., ecological asset). For most ecological assets, the assessment endpoints relate to the maintenance of their long-term viability in the water plan area. Defining assessment endpoints includes a combination of the attributes (e.g. abundance, production rate of biomass, extirpation, etc.) of the entity.

4. Defining Consequence–Thresholds of Concern (ToC) needs to relate directly to the relationship between the flow regime and the critical links an asset has to flow i.e. Defining minimum environmental watering requirements for assets and their associated values.[2].

5. Defining Likelihood–Ecological Modelling information on the critical flow requirements of ecological assets, represented by their ecohydrological rules, used to develop time series of flow-related opportunities from modelled daily river flow simulations representing a range of water resource development scenarios.

6. Assessment of Risk at all locations where hydrological simulations are available within its known distribution, defined by the time series of flow-related opportunities (i.e., likelihood) and the frequency of exceedance of a ToC (i.e., consequence). This approach uses the spatio-temporal sequence of risk generated by a water resource development scenario across multiple locations and incorporates aspects of the population structure and dispersal characteristics of the ecological assets to define spatio-temporal patterns of risk across a catchment.

Criteria groupings are project-based and are grouped below under each relevant component of the EFAP method.

Problem formulation (Steps 1 – 3)

Problem formulation includes identifying the ecological assets (Step 1), defining the ecohydrological rules (Step 2), and defining the assessment endpoints of the system (Step 3).

Ecological assets are the focus of the EFAP approach and represent the broader ecosystem values and requirements of the water plan catchment, as well as represent all flow components relevant to water management. This can include:

• Species
• Populations
• Ecological functions or processes
• Ecosystems
• Places of value.

Ecohydrological rules can be simple or have multiple components which all need to be met to constitute an ecological opportunity. These include critical facets of the flow regime, as well as other requirements, such as:

• Location of flow
• Timing of flow
• Frequency of flow
• Magnitude of flow
• Duration of flow
• Temperature
• Water depth
• Flow velocity.

Assessment endpoints are sensitive and respond to the impact of water resource development. Examples of assessment endpoints can include:

• Abundance
• Production rate of biomass
• Extirpation
• Entities (e.g. valued aspect of the ecosystem, such as an ecological asset).

Assessment endpoints typically cannot be directly measured; therefore, measurement endpoints are used to represent them. Measurement endpoints are expressions of observed or measured responses to a stressor and are measurable characteristics related to the assessment endpoint. Such examples include:

• Provision of species connectivity
• Spawning and recruitment opportunities
• Access to dry season refuge provided by aspects of the flow regime for species
• Provision of critical habitat
• Conditions that support ecosystem structure and/or function.

Effects analysis (Step 4)

The effects analysis involves defining consequence, including identifying the Thresholds of Concern (ToCs)[3]. ToCs are used to represent the frequency with which flow-based opportunities are required to sustain ecological asset viability. This threshold is a point at which small changes in environmental conditions produce large, and sometimes abrupt, responses in ecosystem state or function[4]. ToCs are based on the biology or process knowledge of the asset, including:

• Known time species-based ecological assets will survive without experiencing a flow-based opportunity
• Reproductive longevity of the ecological asset
• Minimum number of annual recruitment opportunities that are required to sustain an asset population over time.

Exposure analysis (Step 5)

The exposure analysis includes defining the likelihood of a scenario occurring. Time series of opportunities represent likelihood or exposure data that is an estimate of the probability of an ecological asset experiencing the critical conditions required at a given location over the assessment period. They are termed ‘opportunities’ rather than ‘responses’ in recognition of the possibility that other factors, including the influence of threatening processes that are not managed by the water plan, may prevent the response from actually occurring even if ideal flow conditions are provided. Criteria for exposure analysis include:

• Flow simulation
• Habitat distribution
• Threats distribution.

Risk assessment (Step 6)

Risk assessment and risk management involves supporting ecological sustainability outcomes in the WP, including the selection of acceptable level of risk. The risk to ecological assets can be assessed at the catchment scale, recognising that populations (and, therefore, values represented by assets) are at a greater risk when multiple locations suffer simultaneous ToC exceedance over time. Options to mitigate unacceptable risks may involve a combination of management responses, such as:

• Changes in infrastructure operating rules
• Water harvesting rules
• Passing flow thresholds
• Minimum waterhole drawdown thresholds.

The process outlined above requires both a sound conceptual understanding of the flow-dependent ecological assets and detailed biological and/or process knowledge relating to their critical flow dependencies in terms of the facets of the flow regime. Targeted monitoring and ecological research should be undertaken for the life of the plan which informs future water plan evaluations[1].

• Field data
• Ecosystem values data
• Attribute data (e.g. ecological assets, catchment components)
• Life history data
• Ecological processes data
• Environmental conditions data
• Threats data
• Management response data
• Flow data and modelling
• Conceptual models

The EFAP method requires a sound conceptual understanding of wetland flora, fauna, and ecology, detailed biological and/or process knowledge relating to their critical flow dependencies[2], knowledge of potential threats and their management, field sampling and assessment skills, water quantity modelling, and data analysis.

A database platform for data storage, manipulation and values assessment, water modelling software, ecological modelling platform, and a Geographic Information System (GIS) platform for result presentation and interpretation.

Outputs are project-specific and include reports and conceptual models, research on ecosystem understanding as it relates to flow, and the potential management controls of specific threats.

• Monitor ecological assets to inform water resource management, particularly flow
• Decision support
• Determine if current flow management strategies are providing the critical flow requirements of ecological assets
• Determine the risk to ecological assets in a plan area under various flow scenarios
• Evaluate if a plan is achieving its stated ecological outcomes through implementing the current flow management strategies.

Designed for federal and state government agencies and natural resource management groups.

• Informs priorities for management actions to improve ecological assets
• Contributes to a growing knowledge base of best available science
• Adaptive monitoring and management
• Risk-based and based on best available science
• Knowledge gaps to inform monitoring are strategically evaluated and imbedded in a structured planning process (see Water Planning Science Plan 2020-2030).

• Not undertaken in all catchments in Queensland
• Outputs require balancing with resources available (e.g. financial)
• Knowledge limitations can reduce the set of assets to those with sufficient information of their critical flow requirements
• Assumes an understanding of the ecological responses associated with flow, but also the interactions of multiple threats
• Assumes current conceptual understanding is correct.

Barriers to Fish Passage in the Queensland Murray-Darling Basin, A report for the south-west Queensland environmental Flows Assessment Program

Barriers to Fish Passage in the queensland Murray-Darling Basin, Phase II: Validation of the “Keller” method in determining discharge at weir drown-out

Environmental Flows Assessment Program Summary Reports

Establishing ecohydraulic flow requirements of an endemic flow-spawning fish species Fitzroy Golden Perch (Macquaria ambigua oriens)

Establishing flow thresholds to support maintenance of river forming processes

Linking cultural values and uses to outcomes for water management

Migratory Fish in the Burdekin, Part 2: Assessing the Frequency of Fish Movement Opportunities

Migratory Fish of the Burdekin Basin Part 1 – Historical Distribution and Timing of Migrations

Migratory Fish of the Burdekin Part 3 – A Trait Based Approach to the Selection of Candidate Species for Modelling

Modelling Risk to Population Persistence of the Pacific Blue-Eye in the Tully River (Queensland, Australia)

Modelling Stress Periods for Eastern Snake-Necked Turtle in the Warrego River (Queensland, Australia)

Optimising environmental management rules to reduce the risk of turtle nest inundation

Review of Water Plan (Border Rivers) 2003 and Resource Operations Plan: environmental assessment report

Review of Water Plan (Condamine and Balonne) 2004: ecological risk assessment report

Review of Water Plan (Moonie) 2003: ecological risk assessment report

Review of Water Resource (Boyne River Basin) Plan 2000 and Boyne River Basin Resource Operations Plan: Ecological risk assessment for selected ecological assets

Review of Water Resource (Burnett Basin) Plan 2000 and Resource Operations Plan: Appendix B–Risk assessment for selected ecological assets

Review of water resource (Warrego, Paroo, Bulloo and Nebine) plan 2003 and resource operations plan : response to Independent Science Review

Stable Low-flow Spawning Fish, Phase II: Assessment of spawning habitat and establishment of a lower threshold for stable low-flows in the Condamine-Balonne and Border Rivers WP areas

Stable low flow spawning fish, Assessment of generic model parameters used to assess risk to stable low-flow spawning fish species in Condamine-Balonne, Border Rivers and Moonie Water Resource Plans

Studying the potential impacts of climate change using extreme environment

Targeted review of Water Resource (Gulf) Plan 2007, Environmental Assessment

The threat of climate extremes to Queensland’s threatened coldwater fish populations

Understanding riverine channel and floodplain morphology in the Condamine-Balonne and Border rivers

Understanding the impact of groundwater extraction on the hydrological behaviour and values of Abercorn Springs

Use of water by floodplain vegetation in the Queensland Murray-Darling Basin

Using molecular information to measure population viability in response to altered flow regimes and dams

Water resource risk register

Wet Tropics Water Resource Plan: Environmental Assessment – Appendix C Risk assessment for selected ecological assets

This page should be cited as:

Department of Environment, Science and Innovation, Queensland (2021) Environmental Flows Assessment Program (EFAP), WetlandInfo website, accessed 30 August 2024. Available at: https://wetlandinfo.des.qld.gov.au/wetlands/resources/tools/assessment-search-tool/environmental-flows-assessment-program-efap/