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RESEARCHER’S FORUM

“Implications for Groundwater access, Extraction and Groundwater Dependent Ecosystems”

March 2013

AcknowledgementsThe GABCC would like to acknowledge the Forum Theme Leaders Dr Brian Smerdon, Assoc. Prof. Andy Love, Mr Travis Gotch and Mr Peter Baker for their considerable leadership and assistance during the planning and implementation of the GAB Researchers Forum. The Forum organising committee members (Lynn Brake, Moya Tomlinson, Saji Joseph, George Gates, and Alistair Usher) are to be commended for generously providing their time and expertise to assist the planning of the Forum. Last but by no means least Gayle Partridge and Paul Hardiman are also recognised for their energy and enthusiasm in the lead up to the Forum, and their active participation helping to successfully implement the event.

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This report should be attributed as the Great Artesian Basin Coordinating Committee Researchers Forum March 2013, Great Artesian Basin Coordinating Committee, 2013.

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Executive Summary

The Great Artesian Basin Coordinating Committee’s GAB Researchers Forum (the Forum) held 27 & 28 March 2013 in Adelaide brought together approximately 100 invited guests from a diversity of GAB sectors including research, government and industry for the purpose of sharing GAB related knowledge and experience, and potentially filling previously identified GAB knowledge gaps.

The Forum delivered the opportunity to communicate 22 presentations providing results of a diversity of significant contemporary GAB related research projects. These research results, together with other relevant research were consolidated in a subsequent workshop sessions. The outcome of the workshop session was to identify and prioritise contemporary GAB research and knowledge gaps, and then scope out potential research projects to address priority knowledge gaps.

The centerpiece of the Forum was the public release of two significant GAB Research Projects, the GAB Water Resource Assessment and NWC Springs Project, representing approximately $23M of Commonwealth, South Australian Government and stakeholder investment. The Projects were launched by the Commonwealth Parliamentary Secretary for Water, together with South Australian Minister for Water and River Murray, and directors from the respective research organisations and Chair of the GABCC.

The Forum combined the communication of hydrolgeological and ecological research outputs in a way that had not been attempted in previous GAB fora. Significant synergies and new perspectives were identified between and within both hydrogeological and ecological type research outputs. The Forum also provided an opportunity for collaborative linkages to be forged between specific GAB researchers and broader GAB stakeholders.

Context

The Great Artesian Basin (GAB)

The GAB is truly an iconic Australian water resource and still largely remains an unsung hero. It has sustained Aboriginal people for thousands of years and now supports a wide range of communities, enterprises and industries.

The GAB is one of the largest underground water reservoirs in the world. It underlies approximately one fifth of the Australian continent, encompassing largely arid and semi-arid landscapes to the west of the Great Dividing Range.

The GAB is a ‘confined’ groundwater Basin comprising a complex multi-layered system of water bearing strata (aquifers) separated by largely impervious rock units. The water yielded by the aquifers is predominantly fresh and in most areas under sufficient pressure to provide a flowing water source when tapped by the drilling of bores. Natural outflows occur at artesian springs. These artesian springs support a diverse array of wildlife in the arid regions.

The major issue in the GAB today is the sustainable use of its groundwater resources. In recent years, close to 600,000 megalitres per year of groundwater has been extracted by bores in the GAB, of which the pastoral industry accounts for over 85%. However, with potential extractive industry development within the GAB, the volume of co-produced GAB water is set to increase. A Strategic Management Plan for the GAB (the Plan) was released in September 2000 (http://www.gabcc.org.au/public/content/ViewCategory.aspx?id=29).

The Plan incorporates national policy principles on groundwater management, sustainability and biodiversity, and complements State and Territory water resource legislation. This helps to ensure that Basin-wide considerations and principles are kept in focus during detailed planning and implementation at the State, Territory and regional level.

Ongoing cooperative management of the GAB water resource by government, industries and communities, based on improved information, effective legislation, advanced technologies and strong partnerships will ensure sustainable use of the treasure that is Australia’s Great Artesian Basin.

http://gabcc.gov.au/publications/great-artesian-basin-strategic-management-plan

Great Artesian Basin Coordinating Committee (GABCC)

The work of the GABCC is largely shaped by the Strategic Management Plan for the GAB. The GABCC was established early in 2004 to replace the Great Artesian Basin Consultative Council, which ceased operation in December 2002.

The primary role of GABCC is to provide advice from community organisations and agencies to Ministers on efficient, effective and sustainable whole-of-resource management and to coordinate activity between stakeholders.

The GABCC is comprised of multi-sectoral representation from government, agriculture, environment, indigenous and industry tasked with advising on the sustainable whole-of-basin management of the Great Artesian Basin. One on the functions of the GABCC is to promote and foster ongoing knowledge and research of key GAB knowledge gaps. To this end the GABCC maintains a Research Development (R&D) prospectus (and funds a GABCC PhD Top-up scholarship program to foster engagement with early career academics promoting opportunities to fill these knowledge gaps).

Further information on the operation of the GABCC Research and Development prospectus may be found at http://www.gabcc.org.au/public/content/ViewCategory.aspx?id=73

GAB Researchers Forum Background

One of the key stated objectives of the GABCC is to promote and foster ongoing knowledge and research of key GAB knowledge gaps. To meet these objectives the GABCC has previously implemented a range of events (including GAB research forums), the last of which occurred in 2005. On 27 & 28 March 2013 the GABCC sponsored a GAB Researchers Forum around a centrepiece of launching the findings of two significant GAB research projects, the Great Artesian Basin Water Resource Assessment and the Allocating Water and Maintaining Springs in the Great Artesian Basin project.

GAB Researchers Forum Aim

The aim of the Forum was to communicate a range of contemporary GAB research findings and facilitate discussion between research stakeholders. Attendees to the Forum received presentations on the key GAB research (including knowledge gaps and implications for management) whilst also being provided the opportunity to participate in targeted workshops.

http://www.gabcc.org.au/public/content/ViewCategory.aspx?id=73

New Great Artesian Basin Conceptualisations

The findings of the GAB Forum will guide government and community decision making and inform development of high quality water policy. The Forum findings are intended to inform resource planning, management and investment decisions through the provision of quality data that is reliable and fit-for-purpose.

Contemporary Great Artesian Basin Research

Great Artesian Basin Water Resource Assessment (GAB WRA)

The GAB WRA provides an analytical framework that may be used by governments, industry and communities to inform resource planning and management and investment decisions through the provision of quality, reliable and fit-for-purpose data. Prior to the initiation of the GAB WRA there was an increasing demand to understand the hydrogeology of the GAB water in light of recent extractive industry development within the Basin, including coal seam gas and mining, so it was considered timely to assess and update the latest geological and hydrological information to support its management.

GAB WRA at a glance:

A two and a half-year $6.25 million project to assess water resources in the Great Artesian Basin (GAB) has been completed by Australia’s key research organisation the CSIRO, in collaboration with Geoscience Australia .

This is the first comprehensive study of the GAB aquifers since 1980. The Great Artesian Basin Water Resource Assessment builds on previous Sustainable

Yields studies. CSIRO lead the two and a half year Assessment, with significant contribution from

Geoscience Australia. Important aspects of the work are being undertaken by Sinclair Knight Merz, Flinders University, South Australian Department of Environment, Water and Natural Resources, and MA Habermehl Pty Ltd.

The GAB WRA findings highlights that vertical groundwater movement is more important than previously thought, which will affect its management.

It is important to understand the complex structure of the GAB, because geological features such as faults, ridges, connection to adjoining geological basins determine the groundwater conditions, including pressure and salinity and how they respond to change.

Allocating Water and Maintaining Springs in the Great Artesian Basin (Mound Springs project)

The four-year $17 million Mound Springs project, funded by the National Water Commission and the South Australian and Northern Territory Governments, pulled together a number of project partners including: the South Australian Arid Lands NRM Board, Flinders University, Adelaide University, CSIRO, and the South Australian and Northern Territory Governments.

Recognising that sound water planning and management requires a sound knowledge base, this project has made substantial contributions to our scientific understanding of the GAB in practical ways that will assist water management into the future. In particular:

For the first time, the locations of all springs in the western margin of the GAB have been mapped and recorded, and baseline condition assessments undertaken. This provides an essential baseline against which to assess the effect of current and future management actions.

The biodiversity value of the iconic GAB springs has been reinforced through genetic analyses that identified 25 new species of invertebrates that are endemic to the springs. The springs are already known to support rare and endangered ecological communities that are recognised under the Commonwealth’s EPBC Act 1990.

The water balance for the NT and SA portions of the GAB has been refined using a number of scientific methods to estimate various types of recharge and discharge processes. This new information challenges long-held management assumptions that the GAB is in a steady state.

New and cost-effective techniques to monitor spring flow rates and ecosystem responses have been developed as a result of this project. These techniques will help provide the information that is needed for informed management decisions.

The project has also developed a risk assessment framework to assess the response of GAB springs and their unique ecosystems to reductions in aquifer pressure, either from long-term natural decline or human impacts.

Translating the project’s research findings into improved water planning and more sustainable management will be a significant and important challenge for the NRM board, governments, local communities and industry into the future.

GAB Researchers Forum - Methods

Forum Presentations

The Forum was divided into three themes including GAB from the east, GAB from the west and GAB ecology. A leader was nominated for each theme and Dr Brain Smerdon, Ass Prof. Andy Love and Mr Travis Gotsch as recognised experts in their respective fields, agreed to lead each of the respective themes.

Forum Presentation Themes

The titles of presentations provided under each of the three themes are listed in text boxes below.

Theme 1 Leader – Dr Brian Smerdon (Photo: Gayle Partridge)

Theme 1: Hydrogeology – GAB from the East Interconnectivity within the Surat CMA. Results of trial aquifer injection programs in the

Surat Basin. Modelling the impact of mining on groundwater -

uncertainty and upscaling. Summary of Office of Water Science projects and

bioregional assessments in the GAB. Great Artesian Basin Water Resources Assessment – overview and key findings.

Great Artesian Basin Water Resources Assessment - updates to the geology of the GAB.

An integrated approach to geoscientific basin models using 3D formats and visualisation

Theme 2 Leader- Assoc. Prof. Andy Love (Photo: Gayle Partridge)

Theme 2 : Hydrogeology– GAB from the WestUpwards leakage around the southwestern margin of the GAB.

Mound Formation. GAB recharge – South Australia. Diffuse recharge &

mountain system recharge along the western margin of the GAB.

GAB recharge – Northern Territory. Conceptual model uranium series. Groundwater chemistry and acid sulfate soil issues. Steady state and transient modelling issues. Diffuse discharge. models using 3D formats and visualisation

Theme 3 Leader - Travis GotchPhoto unavailable

Theme 3: GAB Ecology South Australian perspective, including summaries

of NWC project outcomes. Towards a comprehensive database for the GAB springs

with an update on recent progress in Queensland and New South Wales.

Remote sensing advances in spring management. Groundwater dependent ecosystems - mapping in the

Qld GAB. The Evolution and biogeographic history of the endemic

invertebrate community inhabiting South Australian mound springs.

GAB spring fish management and conservation; a case study from Edgebaston, Queensland.

Impacts of CSG on springs in the Surat CMA. Evaluating risks to GAB springs.

Forum Workshops

The remaining knowledge gaps were captured and were considered by attendees during group work exercises which would contribute to the update of the GABCC Research and Development (R&D) prospectus.

To progress key outcomes of the GAB Researchers Forum it was proposed that:

a) the ranked key research priorities and gaps, identified at Table 1, be used to update the GABCC Research and Development Prospectus, for the endorsement of the GABCC; and

b) That draft GAB research projects (see Table 2) be published on the GABCC website, and also be promoted to relevant agencies responsible for funding GAB related research.

Forum Workshop sessions

The workshop sessions were implemented in the final phase of the Forum to consolidate the skills and experience of all workshop attendees, and provide clear advice on research priorities and potential projects to be considered in GAB water policy and future rounds of GAB related research investment.

Workshop – Ranking of priority research gaps and scoping of potential research projects

Plate 3: Chair GABCC Technical Working Group – Mr Peter Baker

Each presenter was asked to nominate 1-2 knowledge gaps, which were recorded on white boards during the Forum.

Attendees were also given the opportunity to nominate knowledge gaps (via post-it notes on Forum wall). At the commencement of the Forum (registration) attendees were asked to self nominate themselves into

categories of Hydrology, Ecology, Industry, Geology, Social or Government. Each category had a coloured dot to be attached to the presenters name tag.

Prior to the start of the session facilitators arranged to print out all the identified knowledge gaps as a reference for each attendee, for those gaps that have been identified by multiple respondents the number of respondents will also be listed.

At the start of the session attendees were asked to split into table groups that contain people with THE SAME “dot” colours.

Each table nominated a Table leader. Table groups were then be asked to rank (by consensus) the listed knowledge gap by descending priority.

Table groups were nthen asked to provide a brief scope for a potential research project to address the top 1- 2 ranked knowledge gap. Attendees were advised that no funds are available to support any proposed research project, but the scoping document could be used to assist potential GABCC Scholarship Applicants tailor their proposed research programs.

Forum Results

Contribution of sessions to GABCC R&D Prospectus

The GABCC has identified important knowledge gaps in a range of research areas and actively encourages students and researchers to provide proposals to address priority research questions grouped under the following five key knowledge streams below:

1. Understanding the resource2. GAB access infrastructure3. Monitor and measure4. Higher value measure5. Valuing investment

In the tables below a brief summation of each Forum presentation (blue boxes) and potential research projects (red boxes) have been mapped to each of the five key knowledge streams identified under the current GABCC Research and Development prospectus.

Detailed abstracts for selected Forum presentations are at Appendix 3.

Gross Forum Outcomes

Knowledge Stream A – Understanding the resource

The structure and function of the GAB has been researched for more than a century. Natural discharge, and the ecology of springs and soaks, have also been investigated. Monitoring of bores have also contributed to knowledge about the GAB and its management. However, the GAB is a very extensive and complex aquifer system, and knowledge gaps still limit the reliability of management and investment decisions, particularly in relation to understanding or quantifying uncertainty around groundwater flow and groundwater surface water interaction.

Stream A - Presentations

GAB Ephemeral River recharge – Northern Territory.

Sixth of NT is covered by GAB and one sixth of the GAB is in NT

Finke is the largest source of recharge.

The recharge is reducing and is less than 0.002% of storage. Therefore fossil resource

Recharge estimates have driven policy change in the NT re water allocation framework

Recharge zones are coincident with high quality potable water. This coincides with water supply for communities. This then creates vulnerability to

GAB recharge – South Australia. Diffuse recharge & mountain system recharge along the western margin of the GAB.

Regional recharge less than 1mm/year – therefore fossil resource use.

Diffuse discharge.

Preferential discharge Setting long term extraction limits for

groundwater allocation Existing groundwater models

overestimate upward leakage

Hydraulic Head issues.

Variable density of water in parts of aquifers being tested using bores can lead to errors in predicting direction of groundwater flow.

Water density mainly varies with temperature Darcy’s law used to determine potentiometric pressure gradients. A conversion is

required to take account of the variable density. The conversion involves assuming the water in the test bore is fresh.

If conversion is not made the direction of flow predicted may be incorrect. There is no standardised approach to applying the correction – this is an area for

research.

Upwards leakage around the southwestern margin of the GAB.

Explaining water balance from evaporation from phreatic zone from upward leakage concept.

Used remote sensing – salt precipitate/surface moisture. Works in lower lying areas. Where higher upslope water table is lower down and

effect is not detected by the remote sensing technique. Mgmt driver is reducing uncertainty in the water balance and to provide insights

into harvesting vertical leakage. Also data to test water balance and improve modelling Mapped spatial distributing of high leakage zone basis for improving regional

water balance.

Stream A – Potential Research Projects

a) Qualification and Quantification of horizontal and vertical structural controls on Groundwater Flow both within and between GAB aquifers and interconnected overlying and underlying aquifers

Management issue identified by research & describe how research will assist in managing the issue.

The purpose of the research is to enable more robust management that the structural complexity of the GAB. The research is relevant to the following management issues;

Closing the water balance

Harvesting upward leakage

Connectivity with underlying basins

Interpolation of monitoring data

Research description including literature review, field sampling or survey, field or laboratory experiments. Experimental methodologies, sample size and analysis tools.

Quantification of fluxes literature

Costelloe et al.

Harrington et al.

Mapping and Identification literatures

Seismic

Land sat and aerial photographs

GAB WRA

Stakeholders to be consulted Unconventional gas industry

Mining industry

Geoscience Australia

Office of Water Science

Identify how the proposed research relates to existing research, particularly any cross-disciplinary connections

Extension and collaboration with current projects looking at

Polygonal faulting (GAB WRA)

Diffuse discharge (AWMSGAB)

Evaporation (Uni of Melb)

Cross-disciplinary

Geophysics

Structural geologists

Hydrogeologists

Remote sensors

Describe your research design, including literature review, field sampling or survey, field or laboratory experiments. What methodology will you use throughout your project? How will you identify your research sample? How will you collect and analyze data?

Research is designed to estimate diffuse and vertical leakage attributed to Polygonal and regional faults.

Field sampling to involve multi-level coring and multi-sections.

Field or laboratory experiments to include traces, physical properties and hydraulic tests.

Include a rough cost estimate; the cost estimate should include people and resources

Significant drilling/analysis budget ($15M)

Staffing 5FTE for 3 years $3M

Total budget $18M

List any deliverables that are related to the research

Mapping of structural/sections/fluxes

Conceptual models

b) – Qualification and Quantification of the Winton/Mackunda Aquifer and underlying aquitard. “A Portrait of the Rolling Downs Group, a neglected aspect of the GAB”


Quantification of a major but poorly understood part of the GAB water balance.

Current water balance excludes processes occurring in the Rolling Downs Group.

Hypothesis, idea or premise to be tested by the research question

Aquifer – structural integrity and hydro dynamics – recharge estimates.

Aquitard – structural integrity and hydro dynamics.

Is there upward leakage? Trialing a variety of applicable methods and techniques.

Stakeholders to be consulted Water planners and mangers in Commonwealth and State Governments.

Consult:

Water planners

Industry

Land holders and water users

Traditional owner


Builds upon conceptual work of GAB WRA and West GAB spring studies.

Improved water balance will contribute to effective and informal management of the resource. Remote sensing.


GAB WRA 2013, AWMSGAB Vol 1,2 & 3

Conceptual model for polygonal and structural disruption

Knowledge gaps – Quantitative estimates of fluid flow in key regions.

Knowledge Stream B – GAB access infrastructure

Governments and landholders have worked cooperatively to invest in the best science and technology available to rehabilitate bores, improve water delivery infrastructure and change practices to ensure that water is used judiciously. Substantial gains have and are being made in eliminating waste and restoring pressure. These investments need to be protected.

Stream B – Presentations

Results of trial aquifer injection programs in the Surat Basin.

Water management policy lists aquifer injection as a preferred outcome.

Possible issues:o change in pressure from

injectiono Water quality issueso “clogging”

Need for very careful monitoring Need for development of injection

management plans Investigation of feasibility:

o Technicalo Economico Socio - environmental

Great Artesian Basin Water Resources Assessment - updates to the geology of the GAB.

Vertical leakage issue Likely to be both recharge into

and discharge from the GAB to overlying alluvial aquifers.

Where discharge is into alluvial aquifers much of the water is removed for irrigation (e.g. Condamine, Gwydir and Namoi).

Polygonal Sault Systems are extensive across the GAB – result in preferential flow and upwards leakage which, when it occurs into alluvial surface aquifers, is lots to evaporation/evapotranspiration

Stream B – Potential Research Projects

a) Qualification and Quantification of the response of spring systems to closures of a high flowing South Australian GAB bore (Big Blythe)


Three linked projects:

1. Monitor pressure recovery. Multi-level piezometer to examine recovery in connected overlying and underlying strata.

2. Monitor recovery of spring flows in Freeling springs – understand relationships between spring flow rates and aquifer pressure.

3. Monitor recovery/expansion of Freeling Springs ecosystems to improve understanding of ability of spring ecosystems to rebound from short or long-term decline in flows.

Knowledge Stream C – Monitoring and measurement

Jurisdictional water plans have identified a requirement for monitoring pressure and environmental flows. Although monitoring is primarily the responsibility of the jurisdictions, information collected supports both Basin-wide and local assessment needs for planning purposes. Consistency in approach and data collected is vital to a whole-of-resource assessment. Further investigation of monitoring approaches is needed, with a view to cost and the ability to accommodate the complexity of the aquifer structure of the GAB within future monitoring programs.

Stream C - Presentations

Modelling the impact of mining on groundwater - uncertainty and upscaling from developments such as CSG.

Impacts can be significant but not measurable at the scale of data

Therefore models are needed for upscaling result, especially for cumulative impacts over regional scales.

A range of different modelling techniques yield varying results, some of which are quite promising.

Great Artesian Basin Water Resources Assessment (GAB WRA) – overview and key findings.

Groundwater flow models – coverage of whole basin as well as some regional models.

Modelled effects effects of future climate

Changes in ground water level Risks to springs Updating conceptualisation of the GAB Reconsideration of GAB boundary

An integrated approach to development of geoscientific basin models using 3D formats and visualisation.

Utility in displaying multiple uses of resources in one diagram and can integrate a range of resources. e.g. – pastoral, mining, petroleum, gas, unconventional industries, tourism etc.

Can deal with overlapping tenure. – conceptual hydrogeological models. Models need to be useful. These visual models can be very useful for communicating ideas to managers,

regulators, community

Conceptual model and steady state and transient modelling issues

Science needed to inform management and policy Need to use transient rather steady state models otherwise available water may be

overestimated Faulting is most important for water transfer – preferential leakage Need to look at total leakage to get water balance Linkage between mantle and GAB Springs – vertical connection throughout the GAB Diffuse leakage is smaller than preferential via faults

Remote sensing advances in spring management.

Detailed inventory of wetland and substrate characteristics Monitoring of trends in entire wetlands and key communities New understanding of variability over time, climatic & management influences New efficient, objective and quantitative methods that capture entire spring groups and

complexes with sufficient detail to detect individual springs and vegetation health Potential for wider application for mapping and monitoring other GDEs

Stream C – Potential Research Projectsa) The implementation of a multidisciplinary research program to survey the genetic

structure of spring based fauna and flora across the Basin to gain a better idea of biodiversity and identifying potential ‘source’ populations


Management issue is to conserve GAB biodiversity and ecosystems. This research project will inform current conservation priorities in the context of ongoing change. The research would also:

Elaborate on evolutionary relationships

Degree of endemism

Estimate of gene flows to provide information on effective ‘connectivity’

Overlaying information on other areas of research – for example chemical processes, biogeography, predicted changes in hydrological connectivity, pressures.

b) Implementation and interpretation of advanced GAB modelling uncertainty to prioritise locations for future field research.


There are so many knowledge gaps and such little money; we need a better method of prioritising fieldwork.

State the hypothesis, or the idea or premise to be tested. Specify the questions your research will seek to answer.

How to prioritise fieldwork?


GAB WRA 2013

AWMSGAB 2013

New conceptualisation is available but it’s only semi-quantitative.

Fitting a modelling back-end to the new conceptualisation - doesn’t have enough data to support it, but would yield some areas where it can and can’t be constrained. This can help direct where to place further attention for data

gathering.

Stakeholders to be consulted GAB WRA and AWMSGAB teams. GABCC


It would allow prioritisation to other research. Outputs of the model (for example uncertainty), could be interpreted for many purposes (for example hydrology, springs, ecology)

Describe your research design, including literature review, field sampling or survey, field or laboratory experiments. What methodology will you use throughout your project? How will you identify your research sample? How will you collect and analyze data?

Desktop – PhD projects.


PhD scholarships


PhD thesis

Publications (for uncertainty analysis)

Framework model – could be populated and built up to a working model later as more and more gaps get filled.

Knowledge Stream D – Higher value uses

Investment to introduce best practice water use into the pastoral industry has been considerable as this industry uses the most GAB water. New water distribution technologies have opened up opportunities for pastoralists and land managers, and led to benefits across the Basin. Investment in best practice water use for other industries within the GAB could yield further significant benefits and requires investigation.

Stream D – Potential Research Projectsa) Expiration / Extinction risk of endemic GAB organisms at a Basin wide scale


If communities cannot respond to a change then risk of species losses are higher. If endemics are sensitive to a change then extinction risks are higher.


Springs endemics have a narrow tolerance range/threshold. This tolerance range varies between species. A change in flow, land use and introduced species will affect spring habitats (for example water chemistry, turbidity and flora)


Connectivity and dispersal studies (Murphy, Worthington)

AWMSGAB reports

Knowledge Stream E – Valuing investment and allocation

Water from the GAB supports natural and cultural values and human activities. Additional research is required to better value GAB resources, to develop comparative models for industries and activities supported by GAB resources, and to assess the returns on investment in water infrastructure. This will support future investment and management decisions and build on the significant existing investment.

Stream E - Presentations

Groundwater chemistry, origin of spring water and acid sulphate soil issues.

Water chemistry can help in understanding flow

Relates to age of groundwater There are changes to chemistry along flow

lines towards the discharge area. Acid sulphate soils in mound spring are an

issue Impact on fragile ecosystems This does not generally occur widely

across the GA because of calcium carbonate.

ASS problem when water levels decrease. This has occurred in springs across the GAB over relatively recent time (before European arrival).

Mound Formation.

Effective conservation and management of cultural and ecologically important environments

Terrestrial structures composed of similar rock used elsewhere as data sources for palaeoclimatic, palaohydrological and neotechtonics studies.

Modelling change in gross discharge rate over time

Palaeo ecology.

Mound springs untapped archive of info about past climate

Understanding climate – past and future - change and variability

Test models to see how well they model past climate data.

South Australian perspective, including summaries of NWC project outcomes.

Real Time Kinematic Differential GPS provides accurate and repeatable measurement of spring vent elevations

Spring Survey Provide a benchmark of spring status as of 2011. Spring inventory survey consisted of:

o Flow, pH, Conductivity, Temperatureo Flora, Faunao Grazing, Pugging, Threatso 1785 Springs had flow estimates collected; and o 1055 vents had full inventory survey

Towards a comprehensive database for the GAB springs with an update on recent progress in Queensland and New South Wales.

Useful to prioritise the capping of bores in close proximity to high value springs

Stream E – Potential Research Projects

b) Aggregation and collation of baseline data for socio-economic, cultural, hydrological and ecological and hydrological disciplines


Provision of baseline knowledge across all disciplines which is able to be accessed via one portal. To better inform planning, policy development and decision making.


Having a consolidated baseline data set will allow sound decisions for the management of the GAB

Stakeholders to be consulted Government, Industry, pastoral, tourism and scientific


The research project will cultivate cross-disciplinary connections.


Audit of data

Choose suitable interference

Identify gaps

Collect missing info

Add to database

Incorporate database update and maintenance schedule


$10 million


Consolidated database for stakeholders and decision makers in the GAB

Aggregated Forum Outcomes

A ranked list of the top 10 research priorities identified by Forum attendees is at Table 1.

Table 1 - Individual Research priorities as identified and ranked by Forum participants

Comment Rank

Vertical movement and Connectivity studies. Validate through measurement of vertical leakage via remote sensing, polygonal faulting and further examination of major structures

1

Palaeo studies - exploiting the potential to provide climate and environmental histories, connectivity, taxa, connectivity and link to the effect of stressors and site specific fluctuations

2

Establishment of a National, sharable, co-operative GAB database for risk assessment and mitigation (ecology, hydrology, cultural) facilitating reliable data access and storage

3

Development of conceptual models for Springs. Further understanding of the nature and function of GAB Springs, including examination of “extinct” springs, back forecasting, flow/stress relationships and geomorphology of springs

4

Quantification of the socio-economic benefits of the GAB, including its non-value uses, cultural information & knowledge, fiscal information & Identification of options for using co-produced water from CSG activities

5

Collection of baseline data regarding socio-economic conditions in areas of GAB that are targeted for future resource development including ; a) demographics b) recent history of community change c) community services d) local health statistics e) education f) employment opportunities / patterns and g) small business, h) recording GAB histories, I) changed farming practices & j) jurisdictional co-operation

6

Survey of Fauna Cultural and Heritage value of Springs and mapping and Assessment of extinct springs (incl. spring tail survey)

7

Developing a hypothesis about ecology - hydrology relationships for broad spring / 8

GDE types on a regional scale. Improve understanding of hydro ecological relationships with the aim of identifying driving hydrological variables associated with indicators of ecological values.

Spring vent conduits: how does conductivity vary with time or in response to spring flow rate changes?

9

Approaches to monitoring regarding springs, in particular a) what b) where c) how d) best management approaches e) natural variability f) methods to deliver an outcome g) spatial distribution

10

A ranked list of the top 7 potential research projects (1 being the highest ranked priority) identified by mapping to individual research priorities attendees is at Table 2.

Table 2 - Proposed Research projects addressing top research priorities as identified by Forum participants

Rank

Investigation of structural controls on groundwater flow (vertical and horizontal) 1

A portrait of the Rolling Downs Group – Understanding the Winton/Mackunda Aquifer and underlying aquitard. A neglected aspect of the GAB; and

2

The response of spring systems to closure of a high flowing bore in South Australia 3

Undertake genetic structure of spring based fauna and flora (all biota impact) across the basin to better understand biodiversity and to identify potential ‘source’ populations

4

Expiration/extinction risks of endemic GAB organisms at a Basin wide scale. 5

Using GAB modelling uncertainty to priorities future research areas. 6

Provision of baseline data for socio-economic, cultural, hydrological and ecological and hydrological disciplines

7

The Fora successfully identified a diversity of GAB knowledge gaps and then focused upon priority research needs. Table 1 describes a narrowed scope of high priority research needs. Of those areas considered to be a high research priorities workshop subgroups delivered a draft scope for research and knowledge projects to address the identified priority needs. This is shown at Table 2.

Forum Conclusions

Forum attendees identified a handful of specific hydrogeological properties within the GAB as being the highest priority for future research, within this selected group the highest priority for future research being the absolute requirement to quantify the amount of vertical leakage from GAB formations into overlying and underlying geological units.

Forum attendees provided an interim scope for a potential research project to assist with the quantification of vertical leakage (See Potential Research Project 1A). As such this potential project was proposed by Forum attendees as the highest priority potential investment.

Forum attendees identified a secondary research priority being the need to further quantify (through remote sensing and/or other methodologies) the influence of polygonal faulting on leakages from GAB aquifers.

Attendees also flagged a number of ecological parameters within the GAB as priorities for future research, with a key theme being the need to better understand and record ecohydrological relationships and thresholds within the GAB

Appendix 1 – Raw Score and relative ranking of all research priorities identified by Forum participants

Category Comment Score Rank

Socio-economic

Quantification of the socio-economic benefits of the GAB, including its non-value uses 15 19

Identification of options for using co-produced water from CSG activities 14 20

Baseline data regarding socio-economic conditions in areas of GAB that are targeted for future resource development including ; a) demographics b) recent history of community change c) community services d) local health statistics e) education f) employment opportunities / patterns and g) small business 24 14

Sectoral social and economic value of the GAB 13 21

Cultural knowledge and translation (and look for agreement in gaps) 22 16

fiscal evaluation of water in the GAB 27 12

Recording a GAB histories (Indigenous knowledge) 13 21

Talking to farmers about how they have changes their practices since bore capping - piping 1 30

Information sharing between jurisdictions 15 19

GABSI

Assessment of how GABSI has changed farming practices 14 20

Assessment of the value and importance of GABSI for the pastoral industry 14 20

Surveys

Intensive monitoring of the impact of the bore capping and piping program, ie flows to springs, leakage to unconfined aquifers etc 15 19

Fauna Surveys of QLD Springs Systems, incl spring tail survey 35 7

Cultural and Heritage value of Springs 12 22

Mapping and Assessment of extinct springs 13 21

Mapped spatial distribution of high leakage zones provides basis for improving regional water balance estimates and testing concept of ‘harvesting vertical leakage’. 15 19

AGM of Namoi and other paleochannels to look at connectivity 10 24

Current water usage/extraction in the GAB for management 15 19

Hydrogeology

Better characterise GAB LEB surface groundwater interactions 13 21

Spring vent conduits: how does conductivity vary with time or in response to spring flow rate changes? 26 13

Methods to map variability of flux, incl AEM 26 13

Connectivity of Alluvial systems 15 19

Improved potentiometry of the WM Aquifer 14 20

Development of standardised approach to applying corrections to flow direction calculations 12 22

Connectivity Studies - between systems (ie aquifers and aquitards, or springs and groundwater) 42 3

Connectivity between GAB and underlying Basins 36 6

Reactive transport hydrochemistry of coal seam gas water into other aquifers 14 20

Surface water / groundwater interaction studies with regard to a) natural connections and b) variability over time 15 19

Measuring upward leakage rates (inlc. Polygonal faults) 1 30

Need an improved knowledge of connectivity between coal measures and aquifers 1 30

Understand leakage mechanisms 13 21

Vertical movement – how much leakage. Validate through measurement of vertical leakage via remote sensing, polygonal faulting and major structures 118 1

Develop a standardised approach for applying corrections to flow direction calculations 1 30

Condamine connectivity 1 30

Hydrology of Walloons 1 30

Influence of structures upon flow within the basin and between the basin 1 30

Detailed understanding of aquifer responses to long term injection 2 30

Application of regional water balance estimates/models using new data. 30 9

Structural controls (for hydrology and ecology) 28 11

Influence of structure on lateral flows 14 20

Validate updated conceptual understanding 13 21

Remote sensing to detect and map the influence of polygonal faulting especially within the Rolling Downs Sequence 43 2

Potentiometry across major faults 24 14

Establish aquifer geometry and characteristics, hydrochemistry and the mineralogy in the Rolling Down Group. 10 24

Vertical leakage in/out of J-aquifer 15 19

Developing an hypothesis about ecology - hydrology relationships for broad spring / GDE types on a regional scale to improve understanding of hydro ecological relationships with the aim of identifying driving hydrological variables associated with indicators of ecological values 14 20

Database

Common data repository 12 22

Establishment of a National GAB database 33 8

Establishment of a co-operative database for risk assessment and mitigation 20 18

Need for a National Data Base (ecology,hydrology,cultural) 16

National database to extend to worlds springs database 1 30

Data access and storage 14 20

Reliable database for risk assessment 10 24

Data sharing capability 9 25

Management

Co-operative government/industry/research community strategies 19 19

Develop policy and management strategies 11 23

Need to re visit other management polices GAB 1 30

Monitoring

Approaches to monitoring regarding springs, in particular a) what b) where c) how d) best management approaches e) natural variability f) methods to deliver an outcome 14 20

Extend time sequence of satellite record of wetlands back to 1980 15

Analyse time series date to identify the relative contributions of flows, climate and season 14 20

Apply knowledge of surface expression of springs to enhance understanding of sub-surface processes 13 21

Wider application of remote sensing processes for spring characterisation & use methodology to develop a concept/approach of 'envelope characterisation' 12 22

link remote sensing capability with other disciplines/knowledge for enhanced understanding of springs – eg. evapotranspiration, diffuse discharge, mound extent 1 30

Lack of adequate spatial distribution of monitoring data cohesive 21 17

Requirement for monitoring bores in the central part of the Basin 13 21

Cmulative Impact

Cumulative impacts of water extraction 9 25

Analysis and Assessment

Multivariate analysis - how does this methodology contribute to assessment of EPBC issues 11 23

Define thresholds of change for impact assessment 10 24

Modelling

Realistic drawdown surveys 12 22

Development of a local scale conceptual model 6 28

Is it sufficient to produce an updated version of GABTran transient model with complexities for future groundwater modelling? 1 30

Extent to which steady state models overestimate compared to transient models with regard changes in water level results 1 30

How useful are composite models of intensive use to model GAB water levels 1 30

More monitoring networks and systems 1 30

Steady state versus transient models 14 20

Predictive capacity ("natural" vs "development") 1 30

Scale issues, heterogeneity and upscaling 22 16

Modelling water pressure - knowledge gap 15 19

Cumulative impact of various demands on water resource, problematic to predict new impacts of current uses in light of proposed development. 13 21

Springs/Ecology

Better understanding of ET losses from springs or wetlands to inform variation in discharge - wetlands relationships 12 22

Springs conceptual models 14 20

With continuation of the bore capping program will new springs develop? 1 30

“extinct” springs may not be extinct 1 30

Further understanding of the nature and function of GAB Springs 1 30

Past is the key to predicting the future – palaeo studies of the system 1 30

Undertake optically stimulated luminescence dating to find out age of Warburton minor 1 30

Replicate Phragmites results at other sites 1 30

Exploit the potential of other sites to provide climate and environmental histories of the springs themselves and their environment 1 30

Continuing research re relationship between springs 1 30

Future survey and monitoring using remote sensing 1 30

Ecohydrological relationships and thresholds 37 5

Spring complex water balance: how much water remains in the perched/confined aquifer surrounding the springs 13 21

Changes in spring flow in response to aquifer stress 26 13

Audit of existing current management of the Springs (ie how are springs management how?), and development of best management strategies for springs 15 19

How to determine if impacts fall outside range of natural variation (ie establish baselines etc) 14 20

Develop effective quantitative methods for Gambiosia 29 10

Coordinate and compile basic geographic information on GAB Springs for public 28 11

Describe spring endemic species by molecular structure and morphology 13 21

Analyse and define associations of springs dependent species with physical spring characteristics 26 13

Back forecast spring extinction to define modelling capacity 11 23

Experimental manipulation of springs species to define habitat (water chemistry) association 10 24

can we make endemic spring habitat from bores 9 25

cap bores with priority for high value springs 8 26

extend biological understanding of salt scalds 7 27

the geomorphology of spring wetland types 6 28

compare traits of springs dependent and non-spring species 5 29

Understanding the source of spring water 11 23

Connectivity of fauna between springs 39 4

Understand basic tolerance of taxa to environmental factors 14 20

Basic community structure of springs, across complexes 28 11

Need for continuity and linking of approaches in Queensland and South Australia 15 19

Research on historical records for future monitoring of springs to assist with understanding the natural cycles of the springs 14 20

Understanding the effect of climate on surface expression of springs 13 21

Incorporation of test/control studies of impacts of different stressors on springs 10 24

Systemic mapping and conceptualisation of GDE's 27 12

Better understand resilience of flora/fauna 26 13

Causes of seasonal fluctuations in extent of some complexes at Edgbaston Springs 14 20

Better taxonomy 12 22

Understand adaptation mechanisms 23 15

Toad impacts on invertebrates from springs 13 21

Water Balance

Revise GAB water balance using updated understanding 15 19

Appendix 2 – Aggregate score and relative ranking of all research priorities identified by Forum participants

Category Comment Score Rank

Socio-economic

Quantification of the socio-economic benefits of the GAB, including its non-value uses, cultural information & knowledge, fiscal information & Identification of options for using co-produced water from CSG activities 78

Baseline data regarding socio-economic conditions in areas of GAB that are targeted for future resource development including ; a) demographics b) recent history of community change c) community services d) local health statistics e) education f) employment opportunities / patterns and g) small business, h) recording GAB histories, I) changed farming practices & j) jurisdictional co-operation 66

GABSI

Assessment of the value and importance of GABSI for the pastoral industry & how GABSI has changed farming practices 28

Surveys / Monitoring

Intensive monitoring of the impact of the bore capping and piping program, ie flows to springs, leakage to unconfined aquifers, and current water usage/extraction in the GAB for management 30

Survey of Fauna Cultural and Heritage value of Springs and mapping and Assessment of extinct springs (incl spring tail survey) 60

Mapped spatial distribution of high leakage zones provides basis for improving regional water balance estimates and testing concept of ‘harvesting vertical leakage’, including AGM of Namoi and other paleochannels to look at connectivity 25

Approaches to monitoring regarding springs, in particular a) what b) where c) how d) best management approaches e) natural variability f) methods to deliver an outcome g) spatial distribution 48

Extend time sequence of satellite record of wetlands back to 1980 & analyse time series date to identify the relative contributions of flows, climate and season 15

Apply knowledge of surface expression of springs to enhance understanding of sub-surface processes 13

Wider application of remote sensing processes for spring characterisation & use methodology to develop a concept/approach of 'envelope characterisation' link remote sensing capability with other disciplines/knowledge for enhanced understanding of springs – e.g. evapotranspiration, diffuse discharge, mound extent 13

Hydrogeology

Better characterise GAB LEB surface groundwater interactions including a) natural connections and b) variability over time c) connectivity with coal aquifers and d) influence on lateral flows 43

Spring vent conduits: how does conductivity vary with time or in response to spring flow rate changes? 56

Methods to map variability of flux (incl. AEM), Measuring upward leakage rates (inlc. Polygonal faults), 42

Vertical movement/connectivity/structures/ potentiometry – how much leakage. Validate through measurement of vertical leakage via remote sensing, polygonal faulting and major structures Connectivity Studies - between & within systems, 332

Development of standardised approach to applying corrections to flow direction calculations 13

Reactive transport hydrochemistry of coal seam gas water into other aquifers, understanding of aquifer responses to long term injection 16

Developing an hypothesis about ecology - hydrology relationships for broad spring / GDE types on a regional scale to improve understanding of hydro ecological relationships with the aim of identifying driving hydrological variables associated with indicators of ecological values, Application of regional water balance estimates/models using new data, validate updated conceptual understanding 57

Database

Establishment of a National, sharable, co-operative GAB database for risk assessment and mitigation (ecology, hydrology, cultural) for reliable Data access and storage 115

Management

Co-operative government/industry/research community strategies 19

Develop policy and management strategies 12

Cumulative Impact

Cumulative impacts of water extraction 9

Analysis and Assessment

Multivariate analysis - how does this methodology contribute to assessment of EPBC issues 11

Define thresholds of change for impact assessment 10

Modelling

Realistic drawdown surveys, knowledge gaps around modelling groundwater pressure & cumulative impact of various demands on water resource 42

Development of a local scale conceptual model 6

Is it sufficient to produce an updated version of GABTran transient model with complexities for future groundwater modelling? Extent to which steady state models overestimate. How useful are composite models of intensive use 16

Scale issues, heterogeneity and upscaling. Predictive capacity ("natural" vs "development") 23

Springs and Ecology

Better understanding of ET losses from springs or wetlands to inform variation in discharge - wetlands relationships, Spring complex water balance: how much water remains in the perched/confined aquifer surrounding the springs 25

Springs conceptual models. Further understanding of the nature and function of GAB Springs s “extinct” springs may not be extinct, back 96

forecasting, ecology vs flow/stress relationships, geomorphology of springs

With continuation of the bore capping program will new springs develop? can we make endemic spring habitat from capping high value bores 47

Palaeo studies of the system- exploiting the potential to provide climate and environmental histories, connectivity, taxa, connectivity, linkages effect of stressors and site specific fluctuations 184

Undertake optically stimulated luminescence dating to find out age of Warburton minor 1

Replicate Phragmites results at other sites 1

Future survey and monitoring using remote sensing and audit of existing current management of the Springs 43

Ecohydrological relationships and thresholds & understanding the source of spring water 48

Better understand resilience of flora/fauna .How to determine if impacts fall outside range of natural variation (ie establish baselines etc) 28

Develop effective quantitative methods for Gambiosia 29

Coordinate and compile basic geographic information on GAB Springs for public 28

Describe spring endemic species by molecular structure and morphology 13

extend biological understanding of salt scalds 7

Toad impacts on invertebrates from springs 13

Water Balance

Revise GAB water balance using updated understanding 15

Appendix 2 GAB Forum Program

Appendix 3 – GAB FORUM PRESENTATION ABSTRACTS

Research Summary - Diffuse Discharge

Glenn Harrington

Diffuse groundwater discharge from the J-K aquifer on the western margin of the GAB occurs by a combination of very slow upward leakage through massive sections of shale aquitard and comparatively fast preferential flow along fractures and faults. Both mechanisms discharge water into shallow phreatic aquifers. Using physical and environmental tracer techniques, we have determined ranges of effective hydraulic conductivities for these two mechanisms as 0.4×10-13 to 1.2×10-13 m/s and at least 1×10-9 to 1×10-8 m/s, respectively. The former range was derived from detailed vertical profiles of pore-water pressure and chemistry, and relate to a discharge flux of about 3 mm per 10,000 years in two areas of gently undulating surface topography. In contrast, the latter range was derived using helium-4 concentrations in shallow groundwater across a large spatial extent of the western margin, often coincident with playa lakes. Thus surface topography appears to be a useful proxy for groundwater discharge flux; while this may seem obvious in the sense that playa lakes are local groundwater discharge zones, the suggestion that they may also reflect preferential discharge of deep groundwater from the J-K aquifer warrants further investigation as means of calculating diffuse discharge flux at a scale relevant for water resources management.

GAB springs fish management and conservation: a case study from Edgbaston, Queensland

Dr Adam Kerezsy

Bush Heritage Australia

The springs at Edgbaston in central western Queensland comprise the most ecologically diverse Great Artesian Basin complex in Australia, and contain the only populations of the iconic red-finned blue-eye – Australia’s smallest and rarest fish. The red-finned blue-eye is listed as endangered under both Australian (EPBC) and Queensland legislation and as critically endangered by the IUCN. In September 2012 the species was included in a book published by the IUCN called Priceless or Worthless?, the aim of which was/is to raise awareness of the plight of the 100 most endangered species worldwide.

In freshwater systems invasion by alien fish has a dramatic impact on native fish decline, and the impacts associated with alien species are magnified in isolated aquatic ecosystems, particularly in water-remote arid areas. As these impacts are most damaging in areas where there is high endemicity of resident biota, the potential for species decline and loss is therefore extremely high in isolated arid-zone aquatic ecosystems such as the Great Artesian Basin spring complexes in inland Australia.

The red-finned blue-eye, Scaturiginichthys vermeilipinnis was discovered in 1990 by Peter Unmack in spring-fed waters at Edgbaston station, north-east of the town of Aramac in central western Queensland. Edgbaston is located in the semi-arid Thomson River catchment which is part of the Lake Eyre Basin, and became a reserve in 2008 following acquisition by the not-for-profit conservation organisation Bush Heritage Australia. The red-finned blue-eye is the only pseudomugilid fish known from inland Australia, with other blue-eyes generally found in coastal draining rivers of northern and eastern Australia and New Guinea. The red-finned blue-eye reaches a maximum length of 3cm and has only been recorded from the spring complex at Edgbaston.

The Great Artesian Basin springs at Edgbaston are isolated aquatic ‘islands’ within a semi-arid landscape. Currently there are up to 100 springs, soaks or damp areas present at Edgbaston, and the amount of water within each spring ranges from moist areas or small puddles to areas up to 30m wide. Despite variation in the extent of wetlands depending on the moisture status of the substrate, water depth within the springs rarely exceeds 5cm due to the flat landscape. Over long timeframes groundwater discharge to the springs may have been diminished by water extraction through artesian bores. The springs contain slightly saline water (generally up to 1mS/cm) that emerges, devoid of dissolved oxygen, at a constant temperature of approximately 24°C from the spring vents. However, when the water is distributed within the springs it becomes oxygenated and the temperature fluctuates in relation to season and time of day (from close to freezing in winter to close to 40°C in summer).

Discharge springs such as the complex at Edgbaston have been identified as priority areas for conservation in the central Australian arid and semi-arid zones using the criterion of endemicity (Fensham et al. 2011), and the aquatic biota at Edgbaston is the most species-rich of any spring complex in Australia as a result of the diversity of endemic fishes, plants

and invertebrates. In addition to red-finned blue-eye, the Edgbaston goby, Chlamydogobius squamigenus, occurs in at least ten local springs and a large number of endemic aquatic snail species from the hydrobiid, planorbid and bithyniid families are present (Ponder and Clark 1990). Both the ecological community and extant individual species at Edgbaston have been listed under endangered species legislation and are the subject of recovery plans (NCA 1992; EPBC 1999; Fensham et al. 2007, 2008).

Temporary floodwaters provide colonisation opportunities between the isolated springs for all aquatic biota at Edgbaston, and this includes the alien fish eastern gambusia, Gambusia holbrooki. Although the origin of eastern gambusia at Edgbaston is unknown, red-finned blue-eye populations declined from seven to four springs between 1990 and 2007, with colonisation of the springs by gambusia the most likely causal factor (Fairfax et al. 2007). Gambusia have been demonstrated to have deleterious effects on native Australian freshwater fish (Ivantsoff and Aarn 1999) and specifically on a related member of the pseudomugilid family Pseudomugil signifer (Howe et al. 1997). Although the exact mechanism(s) by which gambusia impact red-finned blue-eye is unknown, the recorded patterns of local extirpation (in both Fairfax et al. 2007 and also more recently) indicate that these events are always accompanied by gambusia infestation.

The threats to red-finned blue-eye - a naturally-restricted distribution combined with the imposition of an invasive species - were recognised shortly after its discovery. Prior to being listed as an endangered species it was raised in captivity and attempts were made to establish translocated populations at Edgbaston (Fairfax et al. 2007). However, former keepers and collectors of the species confirm that no captive populations have endured or currently exist. Additonally, all translocations undertaken in the early 1990s (Wager 1994) have failed, most probably due to colonisation by gambusia and/or drying of receiver springs (A. Kerezsy, personal observations 2009 – present).

In recognition of the red-finned blue-eye extinction threat, Bush Heritage Australia began a project in 2009 with the aims of investigating methods of controlling gambusia and relocating populations of the endangered species. The piscicide rotenone was used to evaluate its effectiveness for removing gambusia from selected springs, and small numbers of red-finned blue-eye were relocated to ‘safe’ springs that were unlikely to be colonised by gambusia. It was found that repeated applications of rotenone were necessary to remove gambusia, and also that the application of the chemical did not have a deleterious effect on non-target organisms (such as aquatic invertebrates). Similarly, relocation of red-finned blue-eye was generally successful, and in most instances self-sustaining populations eventuated from small founder populations (~20). Combining the two techniques (gambusia removal and red-finned blue-eye relocation) and expanding the project to include other techniques such as barrier construction around springs and the establishment of captive populations should be pursued in order to prevent the species becoming extinct.

In this talk, results from the initial phase of the project are presented, and the future of the project is discussed with reference to factors that are likely to impact upon its implementation and success.

Evaluating Risks to Great Artesian Basin Springs.

Graham Green

Over much of the area underlain by the Great Artesian Basin (GAB), groundwater provides the only reliable source of fresh water for all human activity, including the pastoral, mining and tourism industries, as well as outback towns. Hence, while the GAB springs have great ecological and cultural value, the utility of the region‘s groundwater results in a number of competing interests that threaten the springs and the health of their attendant ecosystems. With thousands of springs of varying ecological value and vulnerability, natural resource managers require an assessment system that facilitates the prioritisation of mitigation and remediation efforts.

As a component of the NWI project Allocating Water and Maintaining Springs in the Great Artesian Basin, a risk assessment process has been developed to analyse and evaluate risk factors associated with reductions in groundwater pressure in the GAB. Methods for the evaluation of risks are presented that enable the assessment of:

Reductions in spring flow rates in response to aquifer drawdown

Vulnerability of springs to various impacts resulting from a reduction in spring flow rate

Values of spring ecosystems according to a range of key ecological value criteria.

To enable risk assessment of such complex environmental assets, a multi-stage process is presented that facilitates:

Classification of springs and spring groups according to their morphological types

Identification of the degree of threats presented by proposed groundwater developments and the likely impacts on spring flow rates

Assessment of the vulnerabilities of springs and spring groups to identified threats according to their typology and degree of exposure to the threat

Assessment of the specific ecological values of springs and spring groups

A system of ratings for the likelihood of impacts arising, the specific vulnerabilities of springs and specific ecological values of their ecosystems

A simple visual summary of the overall assessment outcomes and the ratings applied

Assessment of the controls, either existing or necessary, to mitigate assessed risks

Acknowledgement of uncertainties in the risk evaluation process and recommendations for further information required to reduce uncertainties.

The risk assessment process is informed and underpinned by sound scientific understanding of the ecological and physical characteristics of springs and the response of these to identified threats. It brings together the most up–to–date understanding of the nature and hydrogeology of GAB springs, including their physical, hydrological, chemical and ecological vulnerabilities, and ecological values. For example, the process for the assessment of the likelihood of impacts to the springs makes use of new information provided for the first time by the outcomes of

this project, including the potentiometric surface map of the main GAB aquifer and accurately surveyed elevations of the GAB springs in South Australia.

The risk assessment process culminates in a summary table displaying individual assessments of the various risk components, the overall level of risk presented to the subject spring or spring group, and indicating which risk components are considered to be contributing the majority of overall risk. It is not recommended that an overall risk ranking or single risk value is derived from the combination of risk ratings. Rather, the risk assessment summary table provides a transparent account of each risk component in order to guide informed decisions regarding appropriate risk mitigation strategies.

The risk assessment process will primarily apply to springs that are within the parts of the GAB where groundwater is under artesian pressure – where groundwater hydraulic head elevation is higher than ground surface level, and the process is most applicable where the level of data available meets the standard that currently exists for the South Australian and Northern Territory parts of the GAB. However the process is intended to be adaptable for application to springs throughout the GAB, including non-artesian parts of the basin.

GAB Recharge – SA

Diffuse recharge & mountain system recharge along the western margin of the GAB

Daniel Wohling

The major findings of our recharge studies along the western margin of the GAB are that 1) modern day recharge is significantly less than discharge and therefore the GAB groundwater system is not in hydraulic equilibrium, 2) the majority of recharge occurred during wetter periods during the Pleistocene, 3) there has been virtually zero recharge for the past 10 000 years and 4) groundwater pressure levels are in a state of natural decline. These findings highlight the importance of effectively managing the resource.

Understanding recharge mechanisms and estimating recharge rates in arid regions can prove difficult and complicated due to large spatial and temporal variability of water fluxes. This talk discusses the role of diffuse recharge and mountain system recharge along the western margin of the GAB. Diffuse recharge can be described as recharge that enters the water table as a result of the infiltration of precipitation and subsequent drainage that occurs uniformly across the landscape (Scanlon et al. 2003). Mountain system recharge is the contribution of mountain regions to the recharge of adjacent aquifers (Wilson & Guan 2004). Ephemeral river recharge – a form of localised recharge resulting from the addition of surface water through stream, river or lake beds to the water table - is not discussed in detail here. The potential for ephemeral river recharge to the J aquifer within South Australia is limited. Tertiary sediments and/or Cretaceous Bulldog Shale overlie the J aquifer along the Stevenson Creek and Alberga River restricting direct recharge. Furthermore, radiocarbon dating of groundwater sourced from the J aquifer in proximity to the Alberga River indicates that there is no active recharge occurring.

The study indicated that mountain system recharge mechanisms have been in operation in the past and are likely to still be in operation. Specifically, hydrogeochemical data, environmental tracers, hydraulic data and rainfall records identified that recharge to the J aquifer has occurred to the east of the Peake and Denison Inlier and at Marla, and to the P aquifer along the western flank of the Peake and Denison Inlier.

By the utilisation of multiple techniques to ascertain diffuse recharge rate estimates, the study ultimately improved the understanding of diffuse recharge mechanisms along the western margin of the GAB and consequently improved the conceptual understanding of the system. Within this study, the areas where diffuse recharge mechanisms to the J aquifer operate were redefined to include zones not previously mapped. Techniques used to assess recharge across these areas provided very low estimates, typically less than 1 mm/year with a mean of ~ 0.15 mm/year. In addition, the study revealed that deep unsaturated zone soil

profiles have mean pore water residence times in the order of 45 000 years. Furthermore, the unsaturated core profiles imply the potential for downward and upward fluxes providing a temporal context to diffuse recharge and suggesting steady state assumptions may not accurately describe the processes occurring at these locations.

Scanlon, BR, Keese, K, Reedy, RC, Simunek, J & Andraski, BJ 2003, 'Variations in flow and transport in thick desert vadose zones in response to paleoclimatic forcing (0-90 kyr): Field measurements, modelling and uncertainties', Water Resources Research, vol. 39, no. 7, p. 1179, DOI10.1029/2002WR001604

Wilson, JL & Guan, H 2004, 'Mountain-block hydrology and mountain front recharge', in: Groundwater Recharge in a Desert Environment– The Southwestern United States, Water Science and Application, Hogan, JF, Phillips, FM & Scanlon, BR (eds.), American Geophysical Union, Washington.

Management and Monitoring of springs in the Surat CMA

Steve Fluke

In Queensland, the Coal Seam Gas (CSG) industry is rapidly expanding in the Surat and Bowen basins. Developing a CSG production field involves pumping water from the coal seams to release the gas adsorbed to coal particles. The reduction in water pressure in the coal seams will cause a reduction in water pressure in overlying and underlying aquifers because there is always some interconnectivity between formations.

The Surat Basin of the Great Artesian Basin supports a range of values including environmentally and culturally significant springs. Potential impacts on these unique ecosystems include both pressure related threats, caused by groundwater extraction activities and non-pressure related threats, such as impacts from feral animals, grazing and land management practices.

Under the Queensland regulatory framework the role of the Office of Groundwater Impact Assessment (OGIA) is to predict impacts on groundwater levels in areas of intensive CSG development and to publish the predictions and required management arrangements in an Underground Water Impact Report (UWIR).

In October 2012, an UWIR was finalised for the Surat Cumulative Management Area. In addition to outlining the predicted groundwater impacts from petroleum and CSG development, the UWIR also provides integrated arrangements for monitoring changes in aquifer water levels and at springs.

The UWIR includes a Spring Impact Management Strategy. The strategy shows the location of springs in the area and describes their nature; the studies undertaken to inform the development of management arrangements set out in the UWIR; specifies the spring monitoring requirements for petroleum tenure holders; and specifies a path to the development of mitigation actions by responsible tenure holders.

The UWIR also identifies key research themes to support the review of the UWIR in three years time. One of the themes relates to spring research.

Managing the predicted impacts on springs

The management of groundwater impacts on springs involves understanding the magnitude of impacts on underlying aquifers; the connectivity between the spring and underlying aquifers; and the ecological and cultural values associated with the spring that may be impacted by changes in groundwater conditions.

A range of assessments were undertaken to inform the understanding about springs and the potential for groundwater impacts. These assessments underpin the management

arrangements established in the UWIR. Predictions from the regional groundwater model, knowledge acquired through spring surveys and connectivity assessments provided the basis for the integrated management arrangements.

Based on the assessments, five spring sites (38 spring vents) are expected to experience impacts of greater than 0.2 metres in their source aquifers at some time in the future as a result of planned CSG development. The maximum impact is predicted to be 1.3 metres. Under the UWIR, these sites are identified for ongoing monitoring, further investigation and development of prevention or mitigation actions. The mitigation actions could include reduction in existing groundwater extraction through substitution of supplies or relocation of extraction or direct actions. Responsibility for developing these mitigation plans is a responsibility of petroleum tenure holders specified in the UWIR.

The UWIR also assigns to tenure holders responsibilities to monitor a wider set of springs.

Enhancing existing knowledge

In addition to the actions that will be carried out by tenure holders, OGIA will lead, coordinate and facilitate research that will improve knowledge about the risk to springs. Outcomes of that research will support future updating of the Surat UWIR and more broadly, contribute to scientific outcomes that may be applied to springs in other areas.

Four key projects will be completed by late 2014.

Classify the hydrogeological settings of spring vents;

Confirm and identify watercourse springs;

Improve the efficiency and effectiveness of spring monitoring; and

Improve knowledge about the cultural heritage values of springs.

Summary

The presentation will summarise the spring sites, assessments and knowledge gained during the development of the UWIR. It will describe the obligations that petroleum tenure holders have under the UWIR in relation to springs. It will then describe the research activities that OGIA is currently carrying out in relation to springs.

Interconnectivity Within the Surat CMA

In Queensland Coal Seam Gas (CSG) industry is expanding rapidly in the Surat and Bowen basins. CSG production involves pumping water from the coal seams to release the gas adsorbed to coal particles. The reduction is water pressure in the coal seams will cause some reductions in water pressure in overlying and underlying aquifers because there will always be some interconnectivity between the formations. The Surat Basin is a sub-basin of the Great Artesian Basin which contains aquifers of high economic, environmental and cultural value. The Condamine Alluvium is also an important water resource that overlies parts of the eastern margin of the Surat Basin.

Under the Queensland regulatory framework the Office of Groundwater Impact Assessment (OGIA) predicts impact on groundwater levels in areas of intensive CSG development and publishes the predictions and required management arrangements in Underground Water Impact Reports.

The Surat Underground Water Impact Report (UWIR) was approved in December 2012. It described the following areas of particular significance with regard to interconnectivity between aquifers.

The Walloon Coal Measures form a significant proportion of the base of the Condamine Alluvium. The extent of interconnectivity is controlled by low permeability materials at the base of the alluvial sequence and at the top of the Walloon Coal Measures. The thickness of the low permeability layer is highly variable.

Over a significant area the Walloon Coal Measures are in direct contact with the overlying Springbok and underlying Hutton Sandstone. The extent of interconnectivity is controlled by the relatively low permeability of the upper and lower horizons of the Walloon Coal Measures which bound the gas producing horizons. While the lower bounding horizon is relatively uniform, the upper horizon is less so.

In the area north east of Roma the Precipice Sandstone of the Surat Basin is in direct contact with the Bandanna Formation which is the gas bearing formation of the Bowen Basin.

To prepare the Surat UWIR a regional groundwater flow model was constructed to make predictions about the impact of planned CSG production. The model was based on current understandings of the hydrogeology of the groundwater flow system. The regulatory framework requires that the UWIR be updated every three years to incorporate new knowledge about the behaviour of the groundwater flow system and planned CSG development.

Accordingly, the UWIR identified six research themes that OGIA will pursue in preparation for the updating of the UWIR. Several of these research themes relate to connectivity. The OGIA approach to research activity is to collaborate and coordinate with other research bodies, and then carry out additional research where necessary. Specific focus areas in relation to interconnectivity are as follows.

Walloon / Condamine Interconnectivity

Although the induced leakage form the Condamine Alluvium into the underlying Walloons is predicted to be relatively small, the alluvium is an economically important aquifer that is already heavily stressed through agricultural development. It is important to build on the current understanding of connectivity. The areas of research activity currently being progressed by OGIA in collaboration with industry and research partners are as follows:

Field Studies: New monitoring bores will be installed and used to assess flow across the alluvium / coal measure contact, in response to pump testing. Water level measurements, and sampling for geochemical studies will be carried out at a whole of system scale as well as in association with the pump testing. The drilling and pump testing will be carried out by petroleum gas companies with close OGIA involvement. Other aspects of the field studies will be carried out by OGIA in collaboration with other research partners.

Conceptualisation: Historic hydrological data will be reassessed along with emerging data from field studies to arrive at possible hydrogeological realisations of the Condamine / Walloon Coal Measure interconnection.

Local Modelling: OGIA is constructing a local scale model which will be used to test hypotheses in relation to interconnectivity.

Walloon / Hutton / Springbok Interconnectivity

Although falls in water pressure in the Hutton and Springbok Standstones in the area of likely impact do not pose widespread threats to bore water supplies from these aquifers, the area is extensive and it is important to build on current understanding of connectivity.

Additional physical and geochemical data will be collected in collaboration with research partners to improve understanding of the distribution and the nature of the aquitards that separate the coal measures from the overlying and underlying aquifers.

Synthesis

Learnings from the interconnectivity projects will enable an improved conceptualisation of the whole of the regional groundwater system, which will support the construction of the next generation of the regional groundwater flow model that will be the basis for the revision of the Surat UWIR in late 2015.

The evolution and biogeographic history of the endemic invertebrate community inhabiting South Australian mound springs

Nick Murphy1 Michelle Guzik 2

1. Department of Genetics, School of Molecular Science, La Trobe University, Bundoora

Victoria, Australia.

2. Australian Centre for Evolutionary Biology and Biodiversity, School of Earth and Environmental Science, The University of Adelaide, South Australia, Australia.

The Great Artesian Basin (GAB) springs are an area of rich endemism in Australia, especially given the fragmented size and location of these arid zone habitats. The GAB springs habitat as a whole is federally recognised as a biologically, culturally and hydrogeologically unique region. The endemic flora and fauna that inhabit the springs are considered relicts from a time when arid Australia was ‘warm and wet’ and are also likely indicators of spring health.

These springs have long held a fascination for biologists. They provide a relictual environment for a suite of endemic species, genera and subfamilies of crustaceans, snails, insects and plants. This talk presents the findings of six years of research examining the evolutionary origins, distributions and population structure of the endemic aquatic invertebrates. Significantly this research has increased the number of endemic arthropod species from 3 to potentially 25 some of which occupy single springs. The phylogenetic history of these species reveals that many have evolved prior to the formation of the springs and has identified clear community-level patterns in biogeographic history, which can be used to better manage this ecosystem. Fine scale genetic patterns reveal that population structure and dispersal is species specific, and also likely to be location specific – an important consideration for ongoing spring management.

There are three key points from the results of these studies to consider for the ongoing management of spring biodiversity.

1. Spring complexes are currently the most appropriate level for the management of endemic species.Genetic variation between spring complexes is generally too high for a general model of spring management, with most species restricted to single spring complexes. However more detailed research is required to adequately assess gene flow and relationships between springs groups within a complex and among springs within a group as evidence suggests that a number of species show a very fine scale of genetic divergence – and that dispersal rarely occurs across the desert – meaning that springs that cease to flow are unlikely to repopulate easily.

2. A large number of species are vulnerable due the fact they are restricted to single spring groups, and in one case a single spring. Importantly many of these species are not currently in protected land, and a number exist in springs that are quite

degraded.

3. Finally, there are many spring groups that deserve special consideration due to the high number of endemic species that they harbour.

This study has revealed a number of important questions that are still to be answered. For example;

Dispersal pathways between springs are still unclear – preliminary studies suggest that direct connectivity between springs is important, meaning that spring flow is critical for ongoing population persistence. Surface stream channels may also be important for dispersal, however the role of long distance dispersal in establishing new populations and maintaining present diversity is unknown.

Local adaptation to the specific groundwater conditions of an individual spring group is likely to play a strong role in shaping the distribution of species – making it unlikely that species can survive in springs other than where they presently persist.

It is likely that habitat characteristics, such as the number of interconnected springs, the size of spring wetlands and the type of vegetation have a significant on species inhabiting springs.

Importantly, the health of species with very small distributions (ie single springs) in the face of habitat degradation, invasive species and reduced flow, is currently unclear. These species are irreplaceable, and the role of these taxa in recycling nutrients means extinction of any species may lead to the loss of other taxa.

It should be noted that this study has been undertaken on the Lake Eyre supergroup of desert springs. The variability in population structure, genetic diversity and evolutionary history across the Lake Eyre Springs and the differences amongst the species studied mean that the results of this study can’t be translated across systems or taxa. Instead it appears that species specific and location specific factors will play a role in structuring GAB spring communities. Thus further research is required and is currently being undertaken across the GAB springs to attempt to understand this ecosystem in order to properly understand and manage this unique ecosystem.

Groundwater dependent ecosystems – mapping in the Qld GAB Bruce Wilson, Mike Ronan & Moya Tomlinson

This paper outlines a proposal to map Groundwater Dependent Ecosystems (GDEs) in the Queensland part of the Great Artesian Basin (GAB). The primary aims of this mapping are to identify where these ecosystems occur and the extent and nature of their dependence on groundwater at a scale that is appropriate for use in regional assessment and management processes. The classification and methods to be used were developed during a project that mapped the GDEs in the eastern Murray-Darling Basin and Burnett regions of Queensland (DSITIA, 2012).

GDEs are defined as "ecosystems which require access to groundwater on a permanent or intermittent basis to meet all or some of their water requirements so as to maintain their communities of plants and animals, ecological processes and ecosystem services" (Richardson et al. 2011). At the highest level there are three classes of GDEs in Queensland mapping (modified from Eamus et al. 2006): 1) surface expression of groundwater (Surface Expression GDEs) which includes GAB “springs”; 2) ecosystems dependent on the sub-surface presence of groundwater (Terrestrial GDEs); and 3) aquifer and cave ecosystems (Subterranean GDEs).

The mapping and classification method used in Queensland includes a number of steps and stages. Firstly existing information is compiled and used as a focal point for a “walking the landscape” (EHP, 2012a) workshop. This workshop is a consultative process with the full range of stakeholders with an interest in GDEs including hydrologists, ecologists, geologists, land managers and planners. During the workshop the landscape is systematically assessed by the stakeholders to gain a common understanding of groundwater features and processes. Expert knowledge about GDEs across the landscape is then elicited and collated and used to identify datasets and rules to map the identified known and potential GDEs.

After the workshop the mapping rules are applied to the best available spatial data to delineate areas that are likely to be groundwater dependent. The resulting conceptual models, mapping rules and maps are used to develop hypotheses to guide field investigations and further research. This leads to an iterative refinement of the information and mapping often in collaboration with original workshop participants. The final stages of the method include final feedback from user groups before finalisation of all products and their release.

The Queensland GDE mapping integrates with existing mapping, particularly the regional ecosystem (Neldner et al. 2012) and wetland (EPA, 2009), programmes so it can be maintained and updated into the future. Other datasets that may be integrated using the mapping rules include groundwater level data, geology, drainage lines, point locations of GDE features, DEMs, and remotely sensed products. The proposed GAB mapping will include ecological inventory as well as assessments of physical parameters.

The development of the pictorial conceptual models (EHP, 2012b) has proved to be an important part of the mapping method for a number of reasons. They enable an often diverse range of stakeholders to develop a common understanding and terminology about the GDE features and then provide a means of assessing the data requirements and rules (models) to map them. The models collate valuable supporting information to improve understanding of the landscape processes that produce GDEs, the broader context and function of GDEs, and assist in the estimation of GDE extent delineated in the GDE mapping. It is expected these models will be updated over time as new information is collected and increased understanding is gained.

All the maps, conceptual models, mapping rules and other information developed through the Queensland GDE mapping programme are made available to the public on the WetlandInfo website (wetlandinfo.ehp.qld.gov.au). For the Queensland GAB project this information will be consistent with basin wide (e.g. South Australia) data sets to enable national, state and regional decision makers to access relevant knowledge that will assist in managing water resources with consideration of the ecological requirements of key environmental assets.

Bibliography

DSITIA. (2012) Groundwater Dependent Ecosystem Mapping and Classification Method: a method for providing baseline mapping and classification of groundwater dependent ecosystems in Queensland. DSITIA, Brisbane [Available online March 2012 - wetlandinfo.ehp.qld.gov.au]

EHP (2012a) Walking the landscape—A whole-of-system framework for understanding and mapping environmental processes and values, 6pp, Queensland Wetlands Program, Queensland Government, Brisbane.[URL: http://wetlandinfo.ehp.qld.gov.au/resources/static/pdf/resources/walking-the-landscape-24-01-13.pdf]

EHP (2012b) Pictures worth a thousand words: A guide to pictorial conceptual modelling, Queensland Wetlands Program, Queensland Government, Brisbane. [URL: http://wetlandinfo.ehp.qld.gov.au/wetlands/Whatyoullfind/Whatyoullfind20130202.html]

Eamus, D., Froend, R., Hose, G., Loomes, R. and Murray, B. 2006, A functional methodology for determining the groundwater regime needed to maintain health of groundwater dependent vegetation. Australian Journal of Botany 54: 97-114.

EPA (2005) Wetland Mapping and Classification Methodology – Overall Framework – A Method to Provide Baseline Mapping and Classification for Wetlands in Queensland, Version 1.2, Queensland Government, Brisbane. [URL: http://wetlandinfo.derm.qld.gov.au/wetlands/MappingFandD/WetlandMandDBackground.html]

Neldner, V.J., Wilson, B.A., Thompson, E.J. and Dillewaard, H.A. (2012) Methodology for Survey and Mapping of Regional Ecosystems and Vegetation Communities in Queensland. Version 3.2. Updated August 2012. Queensland Herbarium, DSITIA, Brisbane. 124 pp. [URL: http://www.ehp.qld.gov.au/plants/herbarium/publications/pdf/herbarium_mapping_methodology.pdf]

http://www.ehp.qld.gov.au/plants/herbarium/publications/pdf/herbarium_mapping_methodology.pdf

http://www.ehp.qld.gov.au/plants/herbarium/publications/pdf/herbarium_mapping_methodology.pdf

http://wetlandinfo.derm.qld.gov.au/wetlands/MappingFandD/WetlandMandDBackground.html

http://wetlandinfo.ehp.qld.gov.au/wetlands/Whatyoullfind/Whatyoullfind20130202.html

http://wetlandinfo.ehp.qld.gov.au/resources/static/pdf/resources/walking-the-landscape-24-01-13.pdf

http://wetlandinfo.ehp.qld.gov.au/resources/static/pdf/resources/walking-the-landscape-24-01-13.pdf

Richardson, E., Irvine, E., Froend, R., Book, P., Barber, S. & Bonneville, B. (2011), Australian groundwater dependent ecosystems toolbox part 1: assessment framework, National Water Commission, Canberra.

“Towards a comprehensive database for the GAB springs with an update on recent progress in Queensland and New South Wales”

After 20 years since the initial surveys in Queensland nd New South Wales, another round of survey has been conducted. These surveys will be compiled in a comprehensive database with the objective of compiling data in a consistent format from all of the springs in the GAB. The nature of this database will be described and other lessons from our experiences in Queensland will be presented.

Remote sensing: advanced mapping and monitoring techniques for spring managementAssoc. Prof Megan Lewis and Dr Davina White The University of Adelaide, South Australia

Introduction

Remote sensing scientists at the University of Adelaide have developed new methodologies and protocols for mapping and monitoring the surface characteristics of the western margin Great Artesian Basin (GAB) springs. A complementary suite of the latest state-of-the-art remotely sensed imagery from satellite and airborne sensors was captured to determine the spatial, temporal, and spectral characteristics of the GAB springs in South Australia. Field protocols were developed and implemented to provide on-ground calibration of the image outputs and assist in image interpretation. This approach was particularly useful for establishing quantitative measures of wetland vegetation extent, distribution of dominant vegetation communities and establishing a relationship between groundwater outflow and wetland vegetation extent (Lewis et al., 2013). Moreover, a remote sensing approach using coincident image and on-ground data collection provides meaningful quantitative results for natural resource managers, which are rigorous, repeatable and scientifically valid. This approach enables quantitative comparison of vegetation over time as well as at different locations and settings. The outputs from the image analysis and allied field protocols provide new insights into the response of vegetation to the flow of groundwater from the GAB and to identify potential impacts of water extractions.

Key findings

Moderate Resolution Imaging Spectrometer (MODIS) hyper-temporal satellite imagery was used in the form of Normalised Difference Vegetation Index (NDVI) 16-day composites, from 2000 to 2010/2011. These data successfully determined the inter-annual and seasonal variability of growth responses of the dominant wetland vegetation types (such as Phragmites australis and Melaleuca glomerata) relating them to climatic influences. In addition GAB spring wetland vegetation was discriminated from the surrounding arid, saline, upland and ephemeral riverine ecosystems. Longer term trends in the spatial and temporal dynamics of Dalhousie and Hermit Hill Spring Complexes were also identified using MODIS imagery time traces, which provided insights into the influence of rainfall on the wetlands (Petus et al., in review).

Very high spatial resolution multispectral QuickBird and WorldView-2 satellite images were used to establish a calibrated relationship between spring wetland vegetation extent and surface spring flows associated with changes in aquifer pressure. Image NDVI was computed and a threshold determined from the calibration relationship with on-ground vegetation cover, which enabled precise quantitative delineation of the extent of the GAB spring

wetlands (White and Lewis, 2011). This high spatial resolution imagery, which covers extensive areas of the landscape in detail, was particularly useful at providing a permanent baseline record of the current status of the GAB spring wetlands at a range of scales from individual springs and spring groups up to entire spring complexes. This approach was successfully applied to a diverse range of spring settings, varying in their extent, distribution and surface expression (Dalhousie, Mt Denison and Hermit Hill Spring Complexes). Changes over time in the wetlands as a response to rainfall, ecological processes, and spring flow were also quantified at an unprecedented level of detail.

Airborne hyperspectral imagery and precise on-ground RTK DGPS surveys were used to characterise the surface expression of several major spring groups and complexes (Dalhousie, Francis Swamp, Freeling and Hermit Hill). Hyperspectral imagery provides rich spectral detail (many narrow wavebands) enabling discrimination of different vegetation communities and types, as well as surface water, minerals, and substrate surface expressions, which were found to have unique spectral characteristics that could be differentiated at the spring group and complex scale. Tasked image captures with concurrent on-ground validation data were collected and analysed to determine geomorphic setting and terrain, spring vent distribution and flow status, distribution and extent of wetland vegetation and dominant wetland vegetation species, zones of near-surface moisture (wetted areas) and surface salinisation (associated with diffuse evaporative discharge of groundwater), as well as change in these characteristics over time. A number of advanced hyperspectral and multispectral remote sensing analyses (waveband indices and spectral filtering and matching) were conducted to accurately delineate the spatial distribution and extent of these spring characteristics within the arid landscape (Lewis et al., 2013).

The hyperspectral analyses revealed wide-ranging characteristics of the four distinctly different spring groups and complexes. This provided rich new baseline information such as vegetation extent, distribution and composition, as well as associated saline surface expressions and surrounding geomorphic landscape setting. Of particular note is the floristic diversity and variability in spring vegetation composition, as well as differences in the geomorphic setting and terrain between sites. Although these spring complexes and groups each have a distinctive character, the hyperspectral analyses revealed some constants across the spring environments. Zones of high surface moisture and diffuse discharge are present at all springs, extending beyond the vegetated spring-fed wetlands. Phragmites australis is present across all spring groups, although its abundance varies from site to site. Where present, it is always in proximity to spring vents and on out-flowing tails. The monitoring over time revealed the dynamic response of springs to climatic conditions, in particular responses to unseasonally high rainfall events following several years of drought.

Management implications and recommendations

Ongoing monitoring using MODIS satellite imagery of wetland area as an indicator of spring ecosystem status is required and needs to acknowledge the strong influence of season and preceding rainfall on extent and greenness of the wetlands. Definition of baseline conditions for larger extent GAB springs must incorporate the seasonal variations and longer term trends identified in this study. The new understanding of spring temporal dynamics has clear benefits for monitoring programs: it establishes the range of natural variation over time, providing objective information of past and current status for interpreting future changes to these sensitive environments, and could be used to define warning thresholds of extreme change.

The very high spatial resolution satellite imagery captured the natural range of variation in the wetland area spring flow relationship under different climatic conditions at the Dalhousie Springs Complex. The generality of these findings was extended by establishment of a similar relationship at Mt Denison Complex and Hermit Hill Complex, which both exhibit quite different geomorphic and hydrologic contexts and a much smaller and interconnected range of spring flows.

These relationships are very significant, as they confirm widely-held assumptions and the underlying premise that wetland area is an indicator of spring flow. Measurements of wetland area for individual springs can provide a surrogate for in-situ flow records that are often difficult to obtain and maintain over time, given their disparate nature within this remote, arid landscape. The remote sensing techniques developed and demonstrated in this study provide an objective, repeatable and cost-effective means of estimating and monitoring changes in spring flow.

Hyperspectral image analysis provided the first thorough documentation and quantitative baseline mapping of the geomorphic context and surface expression of the GAB springs, their associated wetlands and environments. This included high-resolution definition of the spatial extent and distribution of wetland vegetation, selected dominant vegetation species, and surrounding zones of high surface moisture and diffuse evaporative discharge. This new understanding of the spring environments provides valuable information for future ecological studies and assessments of conservation status.

ReferencesLewis, M.M., White, D.C. & Gotch, T.G. (Eds.). Allocating Water and Maintaining Springs of the

Western Great Artesian Basin. Volume VI. Spatial Survey and Remote Sensing of Artesian Springs of the Western Great Artesian Basin. National Water Commission, Canberra (In press).

Petus, C., Lewis, M.M. and White, D.C. Monitoring temporal dynamics of wetland vegetation at Dalhousie Springs Complex in Australia using MODIS Normalized Difference Vegetation Index. Ecological Indicators (In review).

White, D. and Lewis, M. (2011). A new approach to monitoring spatial distribution and dynamics of wetlands and associated flows of Australian Great Artesian Basin springs using QuickBird satellite imagery. J. Hydrology 48:140-152.

Upwards leakage around the southwestern margin of the GABJustin Costelloe

This project used field measurements and remote sensing techniques to quantify, with greater confidence, the component of near surface, vertical leakage around the southwestern margin of the Great Artesian Basin (GAB) in South Australia. The following outcomes were produced:

1. A conceptual model was developed that classified discharge zones into broad categories based on their depth to water table and expected surface characteristics. These surface characteristics were mapped using remote sensing data and the zones were assigned ranges of evaporative discharge estimated from field measurements. The project measured rates of discharge ranging from 0.2 mm y-1 to 542 mm y-1.

2. Discharge rates of >100 mm y-1 generally occurred in areas with shallow groundwater (<1 m depth), moist soils and typically with salt precipitation at the surface (the ‘Liquid Transport Zone (LTZ)’ of the conceptual model). The LTZ occurred around and/or along strike of springs and was assigned a range of 100-300 mm y-1 for use in the estimates of evaporative discharge.

3. Discharge areas with moderately dry surface soils but with the presence of some visible salt precipitation or ‘crusty’ soil surface textures, corresponded to the Mixed Transport Zone (MTZ) of the conceptual model. These areas coincided with groundwater table depths of 1.3-3.7 m and in many cases the MTZ surrounded areas of LTZ. The MTZ was assigned a range of 10-100 mm y-1 for use in the estimates of evaporative discharge.

4. The area surrounding the higher discharge zones (i.e. LTZ and MTZ) typically had dry surface soils and no visible salt precipitation at the surface. However, soil profiles indicated that steady-state evaporative discharge was occurring in a number of areas. These areas correspond to the Vapour Transport Zone (VTZ) of the conceptual model and typically had measured evaporative discharge rates of 0.2-12 mm y -1. The VTZ was assigned a conservative range of 0.2-5 mm y-1 for use in the estimates of evaporative discharge.

5. A range of satellite data were used to classify discharge zones. ASTER and Landsat were used for the automated classification/mapping of evaporative discharge zones. Automated supervised classification using a selection of band ratios and indices were selected to map the discharge zones identified by the conceptual model. Indices mapping soil moisture were used to delineate the LTZ. Indices mapping albedo and salt absorption features in the absence of high soil moisture were used to map the MTZ.Due to a lack of surface characteristics, the VTZ was defined using surface elevation data and interpolated water table surfaces. We imposed an arbitrary radius of 10 km around high discharge zones (LTZ, MTZ) and classified areas within this boundary having depths to the water table of <10 m as forming the VTZ.

6. A landform mapping approach was also used to map the field area into the conceptual discharge zones using a combination of data sources, including satellite and airborne remote sensing, field mapping, field measurements of evaporative discharge and digital elevation data. The landform mapping approach is considered to provide a maximum estimate of the high discharge zones due to its more interpretative nature that lumped areas together. In comparison to the landform mapping approach, the automated classification procedure of the satellite data underestimated the area of high discharge zones due to pixel mixing

effects.

7. The minimum and maximum estimated evaporative discharge rates, for each of the evaporative discharge zones, were applied to the mapped area of these zones to estimate the range of steady-state evaporative discharge over the southwestern margin of the GAB. These discharge estimates were then compared to modelled estimates of vertical leakage from the Bureau of Rural Sciences (BRS) steady-state GABFLOW model.

8. The higher evaporative discharge zones (LTZ, MTZ,) mapped by automated classification of satellite data account for 8-28% of the total vertical leakage component modelled by BRS. Areas of evaporative discharge in the western sub-basin account for 7-24% of the modelled vertical leakage, areas from the mixing zone account for 1-3% and areas from the eastern sub-basin account for <1%. These are considered to represent minimum estimates due to underestimation of high discharge areas.

9. The higher evaporative discharge zones (LTZ, MTZ) estimated by landform mapping account for 73-251% of the total vertical leakage component modelled by BRS. Areas of evaporative discharge in the western sub-basin account for 64-216% of the modelled vertical leakage, areas from the mixing zone account for 5-22% and areas from the eastern sub-basin account for 4-13%. These are considered to represent maximum estimates because of overestimation of high discharge areas.

10. The VTZ estimated around areas of landform mapping accounts for 4-100% of the total vertical leakage component modelled by BRS. Areas of VTZ in the western sub-basin account for 2-48% of the modelled vertical leakage, areas from the mixing zone account for 1-33% and areas from the eastern sub-basin account for 1-18%.

11. The mapped distribution of the high discharge areas has important implications for modelling of the GAB. In the western sub-basin, most of the estimated recharge can be accounted for by evaporative discharge in the high discharge zones located around the Basin margins and along fault structures trending south-east of the Peake-Denison Ranges. This implies that vertical leakage rates distal to the margins are very low, and/or the inflow to this part of the GAB (either western margin recharge or inflow from deeper basins) is currently underestimated.

12. The eastern sub-basin in South Australia is characterized by relatively few areas of high discharge. This indicates that more of the vertical leakage component in the eastern sub-basin is occurring distal to the Basin margins. In contrast to the western sub-basin, the eastern sub-basin generally has much greater depths to the J-K aquifers and also the presence of non-artesian confined aquifers overlying the J-K aquifers over much of its area away from the margins. As a result, the pathways for vertical leakage are likely to be more complex than for the western sub-basin.

Convenor of the GABCC Research and Development Subcommittee - James Hill

Photo: Gayle Partridge

Further information on the Great Artesian Basin Coordinating Committee and its activities can be found

on the Committee’s website at:

www.gabcc.gov.au

http://www.gabcc.gov.au/

gabcc.gov.augabcc.gov.au/.../files/researchers-forum-report.docx · web viewgabcc.gov.au

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