Publication (Technical report): Development of relationships between flow regime and river health: outcomes of a joint CRC for Freshwater Ecology and QLD Department of Natural Resources workshop

Publication Type:	Technical report / Consultancy
Publication Name:	Development of relationships between flow regime and river health: outcomes of a joint CRC for Freshwater Ecology and QLD Department of Natural Resources workshop

Reference Information

Whittington, J. (2000) Development of relationships between flow regime and river health: outcomes of a joint CRC for Freshwater Ecology and QLD Department of Natural Resources workshop. Technical Report 6/2000.

Optional Information

Attached document(s):

- Flow Regime.pdf

Other information:

PDF report attached below

Development of Relationships between Flow Regime

and River Health

John Whittington

Outcomes of a Joint Cooperative Research Centre for Freshwater Ecology and Queensland Department of Natural Resources Workshop

Executive Summary

The Cooperative Research Centre for Freshwater Ecology (CRCFE) and Queensland's Department of Natural Resources (DNR) hosted a 2 day workshop at Clear Mountain Lodge, Queensland, on the 31 st July and 1 st August 2000. This report summarises the presentations, discussions, observations and recommendations of the workshop.

The objectives of the workshop were:

to review progress made by Queensland DNR in response to conclusions and recommendations made by the CRCFE as part of its earlier review of technical elements of the WAMP process in February 2000; and
to explore issues relating to the definition, measurement and reporting of Ecological Sustainable Management within the context of Queensland’s current Water Allocation and Management Planning (WAMP) processes.

The workshop heard presentations on the following key issues:

Ecologically Sustainable Development (ESD) including issues of its definition, reporting and determination of appropriate spatial scales;
the determination of flow preference groups of aquatic macro-invertebrates;
approaches and results of various univariate and multivariate correlations and simulations between flow statistics and macro-invertebrate indices;
multi-metric scoring for separating flow impacts from non-flow impacts on macro-invertebrates
results of new approaches for analysing and reporting water quality data sets from across the State, including the use of reference conditions;
recent enhancements of risk assessment (or traffic-light) diagrams that are used to present risk of ecological degradation in the WAMP's; and
the potential use of the concepts of Limits of Acceptable Change (LAC) and of Ecological Risk Assessment (ERA) within natural resource management planning processes.

The main observations and recommendations from the workshop follow:

Ecologically Sustainable Development

The definition and measurement of 'ecological integrity' is critical for determining whether current and proposed activities are ecologically sustainable.
It is likely that ecological sustainability should be assessed at the level of ecoregions.
Protection of high priority rivers from water resource development is likely to deflect development pressure to other regions.
State-wide assessment and classification of rivers would facilitate the development and prioritisation of planning outcomes based on eco-regions.

Development of river health-flow relationships

The Resource Science and Knowledge Group (RSK) of DNR has made significant progress towards quantifying relationships between flow and ecological condition of rivers, particularly in the Burnett Basin. The methods developed demonstrate the value of multivariate analyses in developing ecologic condition–flow relationships and simulation models for testing management scenarios.
The RSK team is commended in its progress and urged to prepare and submit this work for publication in appropriate peer reviewed journals.
The approaches successfully developed in the Burnett Catchment should now be trialed and developed in other river valleys, where suitable data are available.
Further development of ecologically relevant flow indices, including the use of hydraulic modelling, should be a management priority for DNR.
It is likely the most thorough indication of river health will come from a combination of biotic indicators including fish and macro-invertebrate indices.Drivers of river health (water quality, physical habitat and flow) are required to interpret indicators of biological condition. However, some components may be more cost-effective than others and dropping some components may not result in a significant loss of information. This is an active area of research within the CRCFE.
In developing future monitoring programs, consideration should be given to increasing the number of sites at which macro-invertebrate data is collected, the inclusion of other biotic indicators, and the use of indices based on physical
habitat and ecological processes. DNR should closely monitor research and development of these indices being undertaken in various research programs with a view to their adoption once they are sufficiently developed and tested.
The CRCFE recommends that the internal validity and error propagation associated with the multi-variate analyses that are being developed by DNR for developing relationships between flow and river health be investigated through statistical approaches such as bootstrapping.
The proportion of certain types of habitat change with flow regime. Changes in flow change both physical and hydraulic habitat availability and this will influence or mediate correlations between flow and biota. For example, the area of riffle is very sensitive to flow and consideration of how flow related changes in the relative area of riffle habitat influence the correlation between flow and macro-invertebrates sampled from riffle habitat is required.

Development of methods for analysing water quality data.

Commendable progress has also been made by DNR in the development of methods for critically assessing water quality. RSK are urged to publish this work in peer reviewed journals at the earliest opportunity.
The CRCFE recommends that the outputs from the water quality models be compared and linked to the outputs from the biological models. This will give clues as to the importance of water quality in river-health assessment in these river valleys.

Risk Assessment Diagrams – Traffic Light Diagrams

DNR should examine extending the current risk assessment diagrams into basin-wide risk assessment maps that indicate the current ecological condition of therivers. These maps could also be used to indicate the spatial dimensions of the risk of ecological degradation under various management scenarios.
The term 'Environmental Flow Limit' (EFL) is misleading and should be removed. The term limit implies a level of certainty that, given our current knowledge, does not exist. The risk assessment diagram indicates the level of risk of environmental
degradation associated with a change in flow statistic by means of a colour coding (green through red). By its definition EFL represents a point at which the Queensland Government proposes that this risk becomes unacceptable. This is essentially a social choice made after being informed by science along-side other social and economic inputs.
There is a need to explicitly state ecological outcomes in each WAMP. The size and nature of environmental impacts predicted by the risk assessment diagram are not well defined. Currently the diagrams are simply annotated "minimal impact" and "severe impact". It may be useful to attempt fuller descriptions of the colour coding that indicate the likely outcomes associated with different levels of change, eg. "moderate impact resulting in severe loss of ecological processes".

Limits of acceptable change

The concept of Limits of Acceptable Change may be a useful tool suited for water resource planning where there are a number of competing goals, and particularly where ESD is the ultimate goal.

Ecological Risk Assessment

Ecological Risk Assessment (ERA) frameworks may be a useful tool to guide management of the effects of flow alteration on river health. Research projects to develop ERA frameworks are being undertaken by the CRCFE and others. DNR should monitor this research with a view to trialing this approach should it prove successful.

Introduction

Choosing an appropriate level of water resource development is a social choice made by the community in light of various social, economic and environmental trade-offs. The role of science in this process is clearly one of informing the decision making process of the consequences system of the various options for the health of the river. Science should also suggest alternative flow regimes to optimise ecological outcomes.

The health of Queensland's rivers is a result of current and past management. In some cases, management has resulted in the condition of rivers falling below what the community believes to be acceptable. Where the community seeks to rehabilitate
rivers, science provides the best avenue for defining and choosing between rehabilitation options.

It is a community aspiration that water resource development be ecologically sustainable. While there is not a universally agreed definition of Ecologically Sustainable Development (ESD), the principles of ESD are clearly stated in various
Commonwealth and State Acts. A major issue discussed at the workshop concerned the appropriate spatial scales for assessing ESD.

The challenge for science is to identify the consequences of water resource development and the consequences of alternative development options and to indicate actions to rehabilitate degraded rivers. Science has to ensure that this information is communicated in ways that inform the community's decision-making process. These are difficult tasks, and are an area of active research for the CRCFE and other organisations in Australia.

An aim of the workshop was to review progress that the Resource Science and Knowledge group of DNR has made towards understanding and communicating the relationships between river health and flow regime.

Technical Advisory Panels (TAPs) are appointed to the WAMPs to provide the science needed for an informed decision making process. The TAPs, in providing advice to government, have chosen to present scientific information in a number of ways, including the use of risk assessment diagrams. Risk assessment diagrams, commonly referred to as traffic light diagrams, are used to display the likely risk of ecological degradation from water resource development. The workshop commented on the use and interpretation of risk assessment diagrams in the WAMP documentation.

As well as DNR's development of risk assessment diagrams, there are other significant developments taking place in the range of tools for assisting water resource management. These include the development of sophisticated ecological risk
assessment frameworks, the concept of Limits of Acceptable Change and the importance of spatial scales in ecological assessment. The workshop heard presentations on developments in these emerging areas.

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