Planning for New Water Supplies to Meet Growth in the Pilbara

Planning for new water supplies to meet growth in the Pilbara Department of Water, May 2014

Abstract Secure water supplies are essential to support growth in the Pilbara and achieve the Pilbara Cities vision. The Department of Water has undertaken groundwater investigations, allocation planning and water supply planning to provide certainty on current water availability and identify options to meet additional water demand in the future. The Pilbara region presents unique challenges due to its episodic climate, the distance between water sources and the coastal demand centres and uncertainties around future water demand due to the resource-driven economy. It typically takes three to 10 years to develop a new water supply from conception to implementation. Early planning, ongoing exchange of information across government and industry, and an ability to adapt to changes in the water demand-supply balance are important to achieve transformation of the Pilbara. The Department of Water’s Pilbara regional water supply strategy (2013) brings together three years of work across government and industry. It provides a long-term outlook of water demand and supply options and will guide more detailed planning, investigations and decisions on the water supply options that will be needed during the next thirty years and beyond. It identifies:  the timeframes for when demand is expected to exceed existing supply  the water supply options to meet new demand  actions and triggers for more detailed water supply planning. A high growth scenario, based on the Pilbara Cities projections, is used to inform the timing of investigations and other work needed. This ensures that we are prepared to meet the range of growth scenarios, whilst allowing infrastructure investment to be brought forward or moved back according to actual demand. Importantly, the water demand-supply balance will be reviewed with key stakeholders at least every two years to determine if there have been any significant changes to projected demand or the feasibility of water supply options. Introduction The Pilbara region has experienced considerable growth due to its large mineral and gas deposits. This has seen more water being abstracted at mine sites in the inland Pilbara and an increased volume of dewater surplus to the mine requirements. At the same time, mining growth has increased water demand at the coastal towns and ports due to a growing population, service industries and dust suppression requirements.

of 7 The region’s strategic location close to existing and emerging markets in Asia means that there are further opportunities for growth. The state government’s Pilbara Cities initiative is building on mining sector growth to diversify the economy, grow the population and provide liveable towns and cities in the Pilbara. The Department of Water is working to support this vision by investigating and planning for the water supply options that will be needed during the next thirty years and beyond. Major initiatives include:  securing water supply for the coastal towns and ports through water allocation planning, water supply planning and a program of groundwater investigations  working with other agencies and industries to identify water resources and investment opportunities for agriculture precincts using surplus mine dewater. Regional water demand and supply In 2012, approximately 400 GL/yr of water was abstracted in the Pilbara. Most of this was for the mining sector (Figure 1). Consumptive use was approximately 240 GL/yr, with around 160 GL/yr of mine dewater discharged back to the environment1.

Figure 1 Breakdown of regional water abstraction in 2012 Consumptive water use is projected to increase to between 600 and 900 GL/yr by 2042 (Figure 2).

Figure 2 Projected consumptive water use in 2042 for the Pilbara region

The greatest water demand pressures are expected to be at the coastal towns and ports. The West Pilbara, Port Hedland and Onslow water supply schemes provide most of the water used at these centres. The Harding Dam and shallow, alluvial aquifers are the most important water sources for the coastal schemes. Mine sites and inland towns primarily source their water from local alluvial or fractured rock aquifers. The aquifers and dams in the Pilbara rely on rainfall from irregular tropical lows or cyclones. This means that there can be extensive periods of low or no rainfall, reducing the available water supply. Many of these systems also support river pools and fringing vegetation of high cultural and ecological value. Securing water supply for the coastal towns and ports Detailed scientific, technical and on ground investigations, completed between 2007 and 2010, allowed the department to review allocation limits for nine target aquifers important for supply to the coastal towns and ports. This work informed the development of the Pilbara groundwater allocation plan (DoW 2013a). The plan

1 Some of this water is released to mitigate adverse effects on, and to support environmental values but a large portion is surplus mine dewater.

of 7 provides clarity on the water available to support growth, led to increased allocations for coastal schemes and improves the management and monitoring of groundwater resources and their dependent values. New water supplies are now being developed to meet the needs of the coastal centres in the short to medium-term. In April 2014, the Premier and the Minister for Water officially opened Rio Tinto Iron Ore’s (RTIO’s) new 10 GL/yr borefield in the Lower Bungaroo Valley. This now supplies RTIO’s port and urban needs in the West Pilbara, enabling supply from the Millstream borefield to be wholly available for Karratha and surrounding towns. Additionally, up to 5 GL/yr has been made available by the Department of Water to allow expansion of the Yule and De Grey River borefields to increase supply to Port Hedland. There is potential for a further 2 GL/yr expansion of the De Grey borefield. The Water Corporation’s expansion of the Cane River borefield and a new water source being developed by Chevron (proposed to be desalination of brackish groundwater) will increase supply to Onslow by 0.8 GL/yr. The Pilbara regional water supply strategy (DoW 2013b) also looks beyond these current water supply developments to provide early assessment and support further planning for new water supplies in the medium and long-term. It identifies:  the timeframes for when demand is expected to exceed existing supply  the water supply options to meet new demand  actions and triggers for more detailed water supply planning. Future water demand In consultation with stakeholders, the department has developed high, medium and low growth scenarios to predict future demand for the West Pilbara, Port Hedland and Onslow water supply schemes. Projections show that new water supplies could be needed in the next five to 15 years. The low and medium growth scenarios for the West Pilbara and Port Hedland are based on the historical situation of iron ore growth driving growth in other sectors. The high growth scenario represents a shift away from growth driven solely by iron ore, with higher population growth resulting from a more diversified economy. It reflects the Pilbara Cities vision of a population of 50 000 each in Karratha-Dampier and Port Hedland by 2035. A summary of projected demand is presented in Table 1. Further detail can be found in the Pilbara regional water supply strategy (2013). Table 1 Projected water demand (GL/yr) to 2042 for the West Pilbara and Port Hedland West Port Hedland Pilbara 2012 2022 2032 2042 2012 2022 2032 2042 Urban demand Low 8.5 10 10.5 11 5.5 6.5 8 9 Medium 8.5 11.5 12.5 13.5 5.5 8 10 11 High 8.5 14.5 20 26 5.5 10 14.5 18.5 Industri

of 7 al demand Low 4.5 9 11 13 5.5 14 17.5 21 Medium 4.5 10.5 13 15 5.5 15 19 23.5 High 4.5 11.5 14 16.5 5.5 20 26 31 Total demand Low 13 19 21.5 24 11 20.5 27.5 30 Medium 13 22 25.5 28.5 11 23 29 34.5 High 13 26 34 42.5 11 30 40 49.5 Water demand projections for Onslow are based on the implications of development at the Ashburton North Strategic Industrial Area (ANSIA) on population and service industries within Onslow. A population of 2200 is predicted by 2016 from current gas projects. The high growth scenario assumes growth to 4000 people by 2022 from further conceptual projects at ANSIA. In the medium growth scenario, these new projects are assumed to occur by 2032. Table 2 Projected water demand (GL/yr) to 2042 for Onslow 2012 2022 2032 2042 Low 0.3 0.75 0.85 0.9 Medium 0.3 1.0 1.45 1.6 High 0.3 1.35 1.65 1.8 Water demand forecasts provided in the strategy are estimated at one point in time. All mineral resource development is influenced by fluctuating global demand. Changes in market demand and subsequent deferral or fast-tracking of projects directly affects mining and port water demand, and indirectly affects urban water demand due to flow on effects on the population and service industries. The water demand-supply balance will be reviewed with stakeholders at least every two years to determine if there have been any significant changes. The department is also developing a new market-focused demand and supply model (funded by Royalties for Regions), which will improve the accuracy of water demand and supply forecasts across the state.

Water supply options Future water demand at the coastal towns and ports can be met through a combination of improved water efficiency and recycling, expansion of existing sources and new water sources, such as the West Canning Basin. Short-listed options are summarised in Table 3. Ongoing improvements in water efficiency and recycling are important as they can help delay large investment in new water sources. Significant gains have been made over the past decade, for example RTIO has reduced water used at the Dampier port by almost 30 per cent. The Water Corporation has recently implemented a program expected to save 3.4 GL/yr across the Pilbara (MJA 2012) and will continue to identify and implement further improvements.

of 7 Table 3 Short-listed water supply options Schem Short-listed options Investigations to progress options e West Improved water efficiency and recycling Department of Water2 Hamersley Pilbara Expand Bungaroo Range desktop assessment Desalination (underway) Other aquifers in the Hamersley Range Bungaroo yield confirmation (within Lower Robe aquifer the next five years) Port Improved water efficiency and recycling Water Corporation3 Pardoo borefield Hedlan West Canning Basin – western area investigation (underway) d (Pardoo) or eastern area (Sandfire) Water Corporation De Grey borefield Further expand the De Grey borefield investigation (underway) Desalination Department of Water2 Sandfire resource investigation (underway) Onslow Improved water efficiency and recycling Chevron Birdrong borefield Expand proposed brackish groundwater investigation (underway) desalination plant Proponent investigation of the Lower Recharge of the Lower Ashburton Ashburton aquifer (underway) aquifer Birdrong yield confirmation Further expand the Cane River borefield (following industry investigations) Lower Robe aquifer Implementing the strategy Many of the short-listed options require further planning, investigations and negotiations before a decision can be made to implement them. The water supply strategy identifies actions and triggers to progress the options and allow informed decision-making when they are required. Changes in the level of water demand will trigger a response to move to the different stages of planning and supply development. Ongoing review and exchange of information between government agencies and regional stakeholders will be important to implement the strategy. Recent history has shown that water supply solutions not thought of even a short time ago can arise from new technologies or investigations. The high growth scenario is used to inform the timing of investigations and planning work. This ensures that we are prepared to meet the range of growth scenarios, whilst allowing infrastructure investment to be brought forward or moved back according to actual demand. To support future development of the supply options, the Department of Water is implementing a program of investigations. Based on the experience with Bungaroo, the department commenced a Royalties for Regions funded assessment of similar groundwater resources in the north-west Hamersley Ranges. The preliminary assessment shows that there is potential for around 10 GL/yr which could be piped to Onslow and 20 GL/yr which could be piped directly into the West Pilbara scheme.

2 With funding from the Royalties for Regions program

3 With funding from industry

of 7 In the long term, the West Canning Basin will become increasingly important as a water source in the eastern Pilbara. Investigations and modelling to date has delivered 20 GL/yr for irrigated agriculture, reserved 10 GL/yr for scheme water in Port Hedland and identified 20 GL/yr for mining development. In 2012, the department started a Royalties for Regions investigation to confirm the potential yield in Sandfire area of the West Canning Basin. It appears likely that a total of up to 100 GL/yr could be extracted sustainably from the West Canning Basin.

Future climate assessments are also underway through a project being led by CSIRO in partnership with industry and state agencies. An interim report on the past, present and future climate of the region was released in 2013 (Charles et. al 2013) and spatial-temporal modelling of the implications of climate scenarios on recharge, stream flow and groundwater dependent ecosystems is now being undertaken.

Opportunities in the Pilbara hinterland Dewatering is required to safely mine mineral resources located below the watertable. The department encourages the use of mine dewater on-site to minimise additional abstraction and the effects of releases on the environment. However, the volume of dewater often exceeds on-site requirements. Approximately 160 GL/yr of mine dewater was discharged back into the environment in 2012. The volume of dewatering surplus is expected to increase as more operations move to below watertable mining. There are opportunities to diversify the Pilbara’s economy by using surplus dewater to support irrigated agriculture. Surplus dewater can also help secure local town water supplies in the inland Pilbara. Surplus dewater is being used to supplement Tom Price’s water supply and RTIO implemented the first large-scale irrigated agriculture project using surplus dewater from their Marandoo mine in late-2012. Similar schemes are proposed for other mines and pilot projects are being implemented through the Pilbara hinterland agricultural development initiative. The Department of Water is working with industry and other agencies to build on these existing projects, and identify water resources and investment opportunities for precinct development. A project is underway to collate information on mine dewatering schedules, review available information at dewatering locations to estimate the sustainable yield post-mining, and identify and assess locations and potential water supply scenarios where water could be available to support irrigated agriculture precincts. Conclusion Water is essential for the continued growth of the Pilbara. Early planning, ongoing exchange of information across government and industry, and an ability to adapt to changes in the water demand-supply balance are important to achieve transformation of the Pilbara. The Department of Water has been working with agencies and industry to deliver a suite of investigation and planning work that will allow informed water supply decisions to be made when they are needed.

of 7 Water is also presenting new opportunities, with a range of projects underway in the inland Pilbara to realise the high value of surplus mine dewater. New irrigated agriculture established using this water is an example of an opportunity to diversify the Pilbara’s economy. References Charles SP, Fu G, Silberstein RP, Mpelasoka F, McFarlane D, Hodgson G, Teng J, Gabrovsek C, Ali R, Barron O, Aryal SK, Dawes W, van Niel T and Chiew FHS 2013, Interim report on the hydro climate of the Pilbara: past, present and future, A technical report to the Government of Western Australia and industry partners from the CSIRO Pilbara water resource assessment. Department of Water 2013a, Pilbara groundwater allocation plan, Department of Water, Perth. Department of Water 2013b, Pilbara regional water supply strategy, Department of Water, Perth. Marsden Jacobs Associates 2012, Water Corporation regional integrated water efficiency program – final progress report, a report for the Water Corporation, Marsden Jacobs Associates, Perth.