Great Artesian Basin (GAB) Water Resource Assessment

Transcription

1 Attachment A Great Artesian Basin (GAB) Water Resource Assessment Terms of Reference Aim To assess the hydrological status and condition of the Great Artesian Basin. Background The management issues facing the Great Artesian Basin (GAB) require a better understanding of how the whole system operates. A comprehensive description of the Great Artesian Basin aquifers was published in 1980 (Habermehl, 1980). Since then, while there have been numerous studies in the GAB, there has been no comprehensive compilation of this new work. Combined with an increase in mining and energy development within and near the GAB, there is increasing demand for water resources of the GAB making an integrated assessment of the latest hydrochemistry, groundwater modelling and monitoring information timely. The complexities of the system should not be underestimated, for the GAB is one of the world s largest confined groundwater systems. Areas that need to be considered are: the connectivity, both vertically and laterally, of different parts of the system; the re-pressurisation of confined aquifers in response to management and future development; a reviewing of all the existing stratigraphy, hydrogeology and geochemistry (noting that substantial improvements in understanding will also come with additional geochemistry using advanced techniques); the significance of groundwater discharges to lakes and streams, in addition to the mound springs; and the feasibility of a whole-of-system groundwater modelling capability (for example, building on current models of the whole system or developing models of significant components of the system). Considering all of these aspects should lead to a full re-conceptualisation of the hydrological status and condition of the GAB. This re-conceptualisation will be achieved by the Great Artesian Basin Water Resource Assessment (the Assessment). The Assessment will build on the approach taken by the CSIRO in its Murray-Darling, South West Western Australia, Northern Australia, and Tasmanian Sustainable Yields studies. Consistent with these other studies, the Assessment will provide an analytical framework to assist water managers in the GAB to meet National Water Initiative (NWI) commitments.

2 The Assessment will investigate a number of questions identified in the GAB Coordinating Committee s* Research Prospectus for the GAB. This will present a platform to support the GAB Strategic Management Plan and Sustainability Initiative by providing an update of all existing information and major improvements in understanding, and application of that to an analysis of various management and climate scenarios. Scope The CSIRO and Geoscience Australia have been commissioned to conduct the Assessment. For the purposes of the Assessment, the GAB is defined as; a) aquifers of the Jurassic/Cretaceous period within the geographic extent of the GAB (as shown in the attached map), including parts of those aquifers that are in a sub-artesian condition; and b) relevant shallow, overlying aquifers and surface water, to the extent of their connection with these aquifers referred to in a) above. Consideration will be given to relevant adjacent ground and surface water systems, to the extent of their hydraulic connection with the aquifers in the GAB as defined above. The Assessment is intended to access and integrate all relevant resource data sets held by jurisdictions, industry sectors and research organisations. The GAB Coordinating Committee s 1 Research Prospectus identifies a number of questions to be answered about the GAB. The Assessment will: 1. Develop transparent, consistent and robust methodologies for determining the extent of available water resources in the aquifers of the study area, as follows: (a) review and update the conceptualisation of the hydrogeology of the system and evaluate the adequacy of the existing information base to quantify groundwater processes; (b) assess the recharge, inter-aquifer leakage flows and discharge estimates across the GAB, including the extent of interaction between the GAB and the Murray-Darling, Lake Eyre and Gulf of Carpentaria sub-basins; (c) review models/ methodologies used across the GAB given the limited groundwater modelling and information on the connectedness of hydrological systems; (d) improve models/ methodologies at the whole-of-system scale so that they are capable of incorporating a range of development and regional management scenarios; and 1 * The GAB Coordinating Committee s role 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

3 (e) deliver the products to the timelines set out in Appendix A. This work will link in with and utilise the results of several projects currently being funded by the National Water Commission, as set out in Appendix B. 2. By applying the above models/ methodologies, assess the following: (a) the potential impact of climate change on recharge rates and hydrology of recharge areas. (b) how climate change will affect connections between GAB aquifers and streams (c) the potential changes in discharge, through increased evaporation, including evaporation from springs (d) potential impacts on the GAB water resources from projected future water demands; including petroleum, mining, and other extractive industries including the current and proposed development of coal seam gas (CSG); and the pastoral industry (including intensive livestock farming). (e) the potential impact of current and future predicted water resource development on key environmental asset groups, especially springs; Advice will also be provided on the modelling sensitivity and on any key information gaps that constrain the assessment. 3. Be guided by existing legislation, intergovernmental agreements, GAB water management plans in each State, the GAB Sustainability Initiative and other relevant projects, plans or arrangements. 4. Produce a gap analysis, identifying areas for future work. 5. Be guided by a steering committee chaired by the Commonwealth (Department of Sustainability, Environment, Water, Population and Communities and the National Water Commission), with members drawn from relevant government agencies in the Commonwealth, Queensland, South Australia, New South Wales and the Northern Territory. 6. Commence on 1 July 2010 and conclude by end Data information and models All data must conform to agreed data standards. These will be data standards determined by the Bureau of Meteorology (BoM). Prior to the release of the BoM standards, the standards that will be used are outlined in Appendix C. Geoscience Australia will be the custodian of all data which is Contract Material. CSIRO will be the custodians of computer coded groundwater flow models which are Contract Material. The data and models will be in a form that will be publicly and freely available, (preferably by electronic means), subject to licensing requirements of the source data.

4 The data delivery strategy is outlined in the work plan, and must comply with Regulations under the Commonwealth Water Act Geographic Extent of the Great Artesian Basin

5 By January 2011: The GAB Water Resource Assessment will deliver the following products: Appendix A 1. Project methods report: proposed project methodology. By March 2011: 2. Project overview: project overview, no results. By December 2011: 3. Two interim region reports: hydrostratigraphy, hydrogeology, hydrodynamics and numerical modelling of impacts of climate on two regions (the Central Eromanga and Surat regions). 4. Interim technical report on hydrostratigraphy, hydrogeology and system conceptualisation of the Great Artesian Basin (GAB): report reviewing and updating the conceptualisation of the hydrogeology of the system; assessing the connectedness of the four regions; and evaluating the existing database. 5. Final technical report on review of models and methodologies: a report compiling and evaluating the current state of models and methodologies for the GAB and the appropriateness of these for further development or alternative approaches. 6. Interim 3D visualisation: an interim three-dimensional computer-generated visualisation of the GAB at the whole-of-gab scale (housed at Geoscience Australia). 7. Interim 3D visualisation report: short interim report indicating progress towards the threedimensional visualisation. 8. Database: a database to house all relevant data used and produced in the Assessment (this database does not, however, contain the data and metadata yet). 9. Interim database report: short interim report indicating progress towards the database. By December 2012: 10. Two final region reports: hydrostratigraphy, hydrogeology, hydrodynamics and numerical modelling of impacts of climate and development on two regions (the Central Eromanga and Surat regions), in the context of Queensland Water Commission model results. 11. Two final region reports: hydrostratigraphy, hydrogeology, hydrodynamics and numerical modelling of impacts of climate and development on two regions (the Western Eromanga and Carpentaria regions). 12. Four summary reports: summary of hydrogeology, hydrodynamics and numerical modelling of impacts of climate and development on four regions (the Central Eromanga, Surat, Western Eromanga and Carpentaria regions). 13. Whole-of-GAB report: report on the GAB as a whole including the four regions and their connectivity.

6 14. Whole-of-GAB synthesis: synthesis report on the GAB including the four regions and their connectivity (summary of the whole-of-gab report). 15. Final technical report on hydrostratigraphy, hydrogeology and system conceptualisation of the GAB: report reviewing and updating the conceptualisation of the hydrogeology of the system; assessing the connectedness of the four regions; and evaluating the existing database, in the context of Queensland Water Commission model results. 16. Final technical report on modelling of climate and development: advanced modelling of groundwater potentiometric heads at region to whole-of-gab scale (if appropriate). Detailed assessment on modelling sensitivity and key information gaps that constrain the assessment. 17. Final technical report on environment: detailed assessment of spring groups, wetlands, baseflow and potential ecological impacts of current and projected future changes in groundwater availability. 18. Final 3D visualisation: a final three-dimensional computer-generated visualisation of the GAB at the whole-of-gab scale (housed at Geoscience Australia). 19. Final 3D visualisation report: final report summarising the data that was used and the technical methodology for the three-dimensional visualisation. 20. Database: A database in agreed format with all currently available data and metadata (housed at Geoscience Australia). 21. User guide for database: final report that lists the data that are available and how to use the database.

7 Appendix B Relevant National Water Commission Projects Project Name Sustainable Groundwater Allocations in the Intake Beds of the GAB in NSW Allocating Water and Maintaining Springs in the Great Artesian Basin NT Strategic Assessment Project QUEENSLAND Strategic Assessment Project Queensland Inter-aquifer Leakage Potential Local and Cumulative effects of Mining on Groundwater Resources Investigating the impact of climate change on groundwater resources Description The project will enable more informed and enhanced groundwater management in the intake beds of the Great Artesian Basin in New South Wales. It will assist in achieving GAB Sustainability Initiative outcomes of providing the continuation of access to artesian supplies and opportunities for improved management of water dependent ecosystems, particularly protection of springs, and water-remote ecosystems. The project will build the capacity of water managers and users to sustainably manage the impacts resulting from water allocation from Western Great Artesian Basin. Comprises 2 subprojects: Hydrogeology of the Western region of GAB including Spring flow, vertical leakage and spatial data on spring location and elevation; Land use and GAB spring dependent ecosystems. Development of a water allocation plan for the Northern Territory portion of the GAB. Identification of source aquifers to significant springs that are dependent on groundwater from the GAB. This project will build on previous scoping studies to identify the extent of interaquifer leakage in the GAB. The results will be used to develop policies and standards to protect the groundwater resources of the Great Artesian Basin. The project will: develop guidelines for Environmental Impact Assessments (EIA) that outline both general areas and specific items related to water resources, in particular groundwater, that should be considered during the assessment of mining proposals develop risk-management based tools to assist planners and developers to predict and minimise the cumulative impact of future mining activities on other water users develop guidelines and tools to enable the integrated management and accounting of water resources across multiple mine sites to minimise the impact on water resources. These will be based on an adaptive management framework to enable improved outcomes as knowledge increases. This project will build upon the work carried out by CSIRO in the MDB the other areas. It will provide additional information on the impacts of changes in groundwater systems that impact on groundwater dependent ecosystems, agricultural production and stock and domestic water supply. Additionally, the project will investigate those regions not covered by the CSIRO. The project will make recommendations as to how climate change may be included in National Water Initiative consistent groundwater management and planning processes.

8 Spatial Data Formats and Standards There are spatial data formats and standards that should be met when requesting and receiving data from another organisation. These are detailed in the table below. If the custodian is unable to provide in requested formats the data will need to be cleaned and prepared for use by the Department of Sustainability, Environment, Water, Population and Communities. Appendix C Preferred Data Transfer Formats Vector spatial data ArcGIS Personal geodatabase, ESRI ArcSDE export file or ESRI shapefile. Raster spatial data ESRI GRID or georeferenced image files in commonly used formats such as ERS, TIFF, GIF, BIL, JPEG or ECW. Try to avoid a glossy compression format like JPEG. Tabular data Oracle export format, MS Access 2003, flat ASCII files with comma delimited fields or as MS Excel spreadsheets. Data transfer Data can be provided by CD-ROM, DVD or transferred electronically over the Department's public FTP site. Very small sets of data (<5Mb) may be provided as attachments. All data should be scanned for viruses. Data Quality You should try to ensure that the data meets the following minimum standards. Vector spatial data No slivers, gaps or unwanted overlaps, no unclosed polygons, no missing attributes, no unwanted dangling lines, no self-intersecting polygons. Data accurate to a level appropriate to its publication scale. SDE data has an appropriate tolerance. Arcs densified appropriate to the data scale. Raster spatial data No artefacts from vector data overlays such as line work or text. Data accompanied by information on number of bands, rows and columns to allow it to be easily reconstructed. No lossy compression

9 Tabular data Understandable, rationally constituted (eg. a data table should not be so large as to be unusable). Avoid code sets where possible. If these need to be used, provide look-up tables or metadata describing them. No spaces (except between words in standard text fields), slashes nor ampersands, and dates with full 4-digit year field. Accurate in accordance with the supplier s attribute standards and internally consistent. Table field names not identical to Oracle keywords, and should be meaningful without excessive length. Spatial Reference Map Projections All spatial data to be georeferenced. Spatial data preferably provided in geographic coordinate system, i.e. latitude and longitude, in decimal degree units. If a map projection is used, specify the type of map projection and all of its parameters. If this information is not provided you may find it difficult to integrate the data with other data holdings. Preferred Spatial Reference Datums All spatial data to have a datum specified in its spatial reference. Geocentric Datum of Australia (GDA94) or WGS84 datums. For most spatial purposes these datums are identical. If unable to provide data based on either of the above datums, the datum used for the data must be clearly specified. Data transformed in this study should be saved in GDA94 to allow its use with other data. Metadata The data must be accompanied by metadata. ISO compliant metadata is preferred, however if this is not available metadata should meet at least the ANZLIC ANZMETA V2 standard. Where applicable, additional metadata for data attributes should be supplied. This allows users of the data to interpret the meaning of any codes of look up tables that are used.