Artesian bore pressure

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Artesian bore pressure Artesian bore, Thargomindah Photo:Tourism Queensland Authors Andrew Stevenson and Steven Flook, Department of Natural Resources and Water Reviewer Greg Murphy, Department of

Historically, water from the GAB has been distributed on pastoral properties via thousands of kilometres of open bore drains, resulting in water losses of up to 95% through evaporation and seepage.

1 Artesian bore pressure Artesian bore, Thargomindah Photo:Tourism Queensland Authors Andrew Stevenson and Steven Flook, Department of Natural Resources and Water Reviewer Greg Murphy, Department of Natural Resources and Water Key findings The (GAB) is one of the world s largest underground reservoirs of potable fresh water and underlies approximately 70% of Queensland. Historically, water from the GAB has been distributed on pastoral properties via thousands of kilometres of open bore drains, resulting in water losses of up to 95% through evaporation and seepage. The uncontrolled discharge through free-flowing bores since the late 1800s has resulted in a reduction in water pressure across many parts of the GAB. Over the past 18 years, rehabilitation work has been undertaken in the GAB in a partnership between landholders and government. This work has resulted in more than 500 free-flowing bores being rehabilitated, the replacement of 8000 km of open bore drains with piping, and water savings of ML/yr. The Sustainability Initiative (GABSI) began in 1999 and involves rehabilitation of uncontrolled artesian bores and replacement of open bore drain distribution systems with piping. The costs of the project are shared among the Commonwealth and State governments and landholders. This investment has led to significant pressure recovery. Besides this investment in infrastructure, the establishment of a management framework for the GAB has ensured significant pressure recovery in many areas. To ensure the long-term sustainable management of this resource, including the protection of existing users, the environment and investments made under GABSI, a water resource planning process was finalised in February 2007 for the Queensland section of the GAB. The final plan provides a framework for the sustainable allocation and management of this resource for the next ten years. Indicators and summary of status Indicator Number of rehabilitated artesian bores Total length of bore drains piped Trends in pressure Flow rates from artesian bores Status of indicator Number is increasing in target areas across the GAB. Approximately 500 uncontrolled bores have been rehabilitated since Increasing in target areas across the GAB. Around 8000 km of bore drains have been rehabilitated since Pressure recovery is occurring in many areas across the GAB. Around half of artesian bores monitored showed an increase in pressure. Stabilised or increasing across the GAB. 175

2 Importance Extent of the resource The (GAB) underlies approximately 22% of the continent and extends beneath arid and semi-arid regions of Queensland, New South Wales, South Australia and the Northern Territory. Figure 5.11 provides a simplified overview of the operation of the GAB, outlining recharge mechanisms and the artesian and subartesian characteristics of the resource. In excess of 70% of the GAB underlies Queensland. The reliable supply of potable fresh water has made this resource vital for the social and economic development of many arid regional areas in the state s west. Figure 5.12 outlines the extent of the resource, recharge areas and springs connected to the GAB. The GAB is inherently artesian. This is beneficial because it provides the necessary pressure for water reticulation without the need for pumping. This characteristic also supports the flow of water to nationally significant environmental and cultural sites. Socioeconomic values Since the construction of the first artesian water bore in Queensland in 1879, the GAB has played a very significant role in the development of many western areas. The discovery and exploitation of the resource were instrumental in development of the pastoral industry and settlement of many arid areas overlying the GAB: here were the necessary water supplies for stock, domestic and industrial purposes (Blake and Cook 2006). While many water users have access to both surface water and groundwater supplies, water from the GAB is unaffected in the short term by seasonal changes in rainfall and the consequences of drought conditions. In addition to being a highly reliable water supply, the GAB s artesian nature provides a relatively low-cost means of distributing the water. A broad range of users are dependent on this resource (figure 5.13). Stock and domestic uses are by far the largest, accounting for approximately 78% of the total water taken from the GAB (Cox and McKay 2006). The industrial, mining and irrigation sectors are also significant users. However, opportunities for irrigation are limited in many areas due to unsuitable water quality and the consequences of its application on some soil types. Currently irrigation is predominantly limited to small-scale production of fodder crops. Although urban water supplies represent only 5% of the total water use from the GAB, a large proportion of towns overlying the resource rely solely on this supply (Cox and McKay 2006). A total of 84 towns rely partially or entirely on urban water supplies from the GAB. The reliability of supply from this resource is vital for the development and the continued existence of many western centres. Bedrock Aquifer Potentiometric surface Springs Flowing bores (artesian) Direction of water movement Impervious material Recharge areas Non-flowing bore (subartesian) Figure 5.11 Operation of the Source: DNRM 2005a Mount Isa Weipa Karumba Croydon Boulia Birdsville Georgetown Longreach Cairns Charters Towers Mackay Barcaldine Quilpie Charleville Roma Rockhampton Toowoomba Figure 5.12 The extent of the in Queensland Source: DNRM 2005b Stock and domestic 78% Mean sea level Intake areas Sandstone outcrop Springs Stock intensive 3% Direction of flow Bundaberg Goondiwindi BRISBANE Figure 5.13 Summary of water use from the Great Artesian Basin by sector Source: Cox and McKay 2006 Urban 5% Irrigation 7% Industrial and mining 7% 176

Cultural and environmental values A range of cultural and environmental heritage values are associated with the GAB, largely focused on areas where water emanates at the surface in the form of

3 Cultural and environmental values A range of cultural and environmental heritage values are associated with the GAB, largely focused on areas where water emanates at the surface in the form of artesian springs, and on baseflow to rivers and streams and other groundwater dependent ecosystems. Across the Queensland section of the GAB there are in excess of 310 spring complexes (Fensham and Fairfax 2005). Most of the recharge springs exist along the eastern margins, on the Great Dividing Range, while major clusters of discharge springs are found on the western margins of the GAB. Many of the springs in discharge areas have unique ecological conservation value because, in otherwise arid land, they provide oasis habitat for a variety of species, including plants, fish and snails that do not occur anywhere else (Cox and McKay 2006). Many of these spring ecosystems are also listed as threatened under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). Indigenous communities across the GAB have significant historical and ongoing spiritual, mythological, ceremonial and subsistence associations with both recharge and discharge springs of the GAB (CQCHM 2005). Pressure and condition Pressure trends Since first development of the GAB in the late 1800s, the prevailing use of uncontrolled bores and open bore drains has resulted in significant pressure declines in many areas. However, the establishment of a legislative framework to manage extraction of water and the significant investment in capping and piping programs by landholders and government have resulted in measurable pressure recovery in key areas across the GAB. The combined result of these activities on pressure levels in Queensland is presented in Figure Mount Isa Weipa Karumba Croydon Georgetown Cairns Pressure increase since cap and pipe programs began 0 4 m 4 8 m >8 m Charters Towers Mackay Boulia Longreach Barcaldine Rockhampton Birdsville Quilpie Charleville Roma Bundaberg Toowoomba Goondiwindi BRISBANE Elizabeth Springs, discharge spring of the GAB, south-east of Boulia Photo: Steven Flook, DNRW Figure 5.14 Pressure recovery across the Great Artesian Basin in Queensland Source: DNRM 2005b Increasing demand Prevailing drought conditions and the limited availability of surface water in many areas have resulted in increased demand for groundwater from the GAB and other groundwater systems across the state. Demand for water is increasing, particularly along the eastern margins of the GAB. Interest is predominantly from the irrigation, mining, stock intensive (feedlots) and industrial sectors. Demand for water for stock intensive purposes is relatively high in the south-east of the GAB where climatic conditions are favourable and specialist services such as beef processing plants are close by (Cox and McKay 2006). Demand for water from a broad range of sectors is expected to continue to grow. As a result, better measures for controlling and managing water extraction were needed to protect the long-term viability of the GAB. In response to 177

these concerns, no additional extraction of water has been authorised since February 2005 to allow for development of a state management framework for the GAB.

4 these concerns, no additional extraction of water has been authorised since February 2005 to allow for development of a state management framework for the GAB. To provide for long-term holistic management of the GAB, a water resource plan under the Water Act 2000 was completed in March Under this plan, access to limited amounts of new groundwater will be available in accordance with the established allocation and management framework, which includes protection of springs, the take of water for existing use, and maintenance and improvement of trends in water pressure. Uncontrolled bores Historically, water from the GAB was distributed along thousands of kilometres of open bore drains. This water supply has been invaluable for development of pastoral enterprises throughout western Queensland. However, free-flowing bores and open bore drains result in losses of up to 95% of water through evaporation and seepage. Significant land-management issues can also result from use of uncontrolled bores and open bore drains. Increases in feral animal abundance, pest plants and erosion are commonly associated with the use of bore drains in arid and semi-arid environments. Pastoral water users realised as early as 1891 that bore flow rates were falling, indicating a decline in artesian pressure. Some bores initially flowed at rates of up to 3000 ML/yr. In marginal areas some bores have ceased to flow above the ground s surface, and most flows are now between 3 and 2000 ML/yr (GABCC 1998). Since rehabilitation work began in 1989, water savings, pressure recovery and improved land management outcomes have occurred in key areas across the GAB. Significant improvements in groundwater use efficiency have been achieved and will continue to be realised through replacement of bore drains with piping and by controlling bore discharge. Response Strategic Management Plan The Strategic Management Plan (GAB SMP) represents the first whole-of-resource management plan agreed to by all governments responsible for management of the GAB. The GAB SMP was released by the Consultative Council in September 2000, and represents an agreed commitment from governments, users and other stakeholders on policies, programs and actions necessary to attain optimum economic, environmental and social benefits from the existence and use of the GAB s groundwater resources. water resource plan The Water Resource () Plan 2006 (the Plan) provides a regulatory framework for water allocation and long-term management of the GAB in Queensland. The Plan provides for sustainable management of the GAB s water resources, including limits on the take of additional water. The Plan will ensure that the resource is managed sustainably for consumptive and environmental use into the future. Key outcomes from the Plan include: protection of the flow of water to springs and baseflow to watercourses that support significant cultural and environmental values; protection of existing users from new extraction and users; and provision of water within sustainable limits for new users. Recharge of GAB aquifers Groundwater flow is generally from the recharge or intake areas to springs and other natural discharge areas in the west and south-west of the GAB. The rate at which water flows through the sandstones varies between less than 1 m a year and 5 m a year. The aquifers of the GAB are recharged from infiltration of rainfall and leakage from streams into outcropping sandstone, and through sandy soils into the sandstones. This occurs mainly on the eastern margins of the GAB, along the western slopes of the Great Dividing Range. Research has revealed that three types of recharge processes occur within the intake beds: diffuse rainfall, preferred pathway flow during high-intensity rainfall events, and preferred pathway flow from stream or aquifer leakage. The recharge rates associated with these processes vary from 0.03 mm a year for diffuse recharge to 30 mm a year for river/aquifer leakage (DNRM 2005c). The Blackall Woolscour Photo: Tourism Queensland 178

5 The Resource Operations Plan, released in February 2007, details the arrangements for achieving these outcomes. This document includes details on how monitoring and metering will be undertaken, and how protection from excessive future use will be provided for springs and existing water users. These plans result from extensive consultation with the community, peak stakeholder organisations, Indigenous communities, industry and other jurisdictions responsible for management of the GAB. This process ensured that all concerns and issues identified by stakeholders were considered during development of the planning framework. Sustainability Initiative (GABSI) A number of programs have been undertaken since 1989 to repair uncontrolled bores and to replace open drain systems with closed distribution systems. The primary aim was to recover pressure in the GAB. Since 1989, the Commonwealth and State governments and landholders have spent approximately $91 million on rehabilitation. In Queensland this investment has resulted in savings of in excess of ML/yr. Approximately 500 uncontrolled bores and 8000 km of bore drains have been rehabilitated. The latest iteration of the cap and pipe programs in Queensland is the The Sustainability Initiative (GABSI). This program is jointly funded by the Commonwealth and State governments and landholders. The program commenced in 1999 to provide continued support to landholders who were rehabilitating uncontrolled artesian bores and replacing open bore drains with closed distribution systems. Under GABSI, State and Commonwealth governments finance 80% of the cost of rehabilitating uncontrolled bores and 60% of the cost for replacing bore drains with piped systems. Individual landholders contribute the remaining costs. Photo: Laurence Knight Investment in capping and piping programs over the past 18 years has resulted in measurable improvements across the GAB. Bore monitoring data collected since capping and piping activities began show an increase in pressure in half of all artesian bores monitored. A total of 341 bores have increased in pressure by up to 8 m and 31 have increased by more than 8 m (DRNM 2005a). In addition to improvements in pressure, significant improvements in land management are associated with replacement of open bore drains with closed distribution systems. When bores are capped and piped, there is potential to reduce pest plants, feral animals and land degradation, including erosion and salinisation. References Blake, T. and Cook, M. 2006, : Historical Overview, Department of Natural Resources and Water, Brisbane. Cox, R. and McKay, A. 2006, The Water Resource Plan, Water in Mining Conference 2006, Department of Natural Resources and Water, Brisbane. CQCHM 2005, Statement concerning the cultural heritage values and places associated with springs, unpublished, Central Queensland Cultural Heritage Management, Brisbane. DNRM 2005a, Draft Water Resource Plan: Overview, Report and Draft Plan, Department of Natural Resources and Mines, Brisbane. DNRM 2005b, Draft Water Resource Plan: Information Report, Department of Natural Resources and Mines, Brisbane. DNRM 2005c, Hydrological framework report for the Great Artesian Basin water resource plan area, unpublished, Department of Natural Resources and Mines, Brisbane. Fensham, R.J. and Fairfax, R.J. 2005, Ecological assessment of springs in Queensland, unpublished. GABCC 1998, : Resource Study, Great Artesian Basin Consultative Council, Fortitude Valley, Brisbane. 179

National Farmers Federation. Submission to the Draft Great Artesian Basin Strategic Management Plan 2018

National Farmers Federation. Submission to the Draft Great Artesian Basin Strategic Management Plan 2018 National Farmers Federation Submission to the Draft Great Artesian Basin Strategic Management Plan 2018 9 November 2018 NFF Member Organisations Contents NFF Member Organisations Contents 2 Introduction