When the well runs dry: a spatiotemporal assessment of the Wheatbelt's water vulnerability Boruff, B.J.¹, and Biggs, E.², Pauli, N.¹, Clifton, J. ¹ and Callow, N.¹ ¹School of Earth and Environment, The University of Western Australia ²Geography and Environment, University of Southampton

Water Vulnerability Water is irreplaceable and non-substitutable Land dev. + pop. growth + climate change = Water Scarcity Climate change = modifying supply, demand, and quality Vorosmarty et al. (2010)

Measuring Water Vulnerability Defining Vulnerability: ‘the interface between exposure to the physical threats to human well-being and the capacity of people and communities to cope with those threats. Threats may arise from a combination of social and physical processes. Human vulnerability thus integrates many environmental concerns’ (UNEP 2002) Integrated index = greater potential to effectively improve livelihoods Address water scarcity Promote equal development More informative for decision-making e.g. Sullivan and Meigh (2005); Sullivan et al. (2008); Cohen and Sullivan (2010); Sullivan (2011);

Western Australia’s Wheatbelt “Water supply is fundamental for supporting and sustaining community and industry development in the Wheatbelt.” (WDC, 2013) Significant reliance of scheme water Groundwater salinity increasing Industrial sectors highly dependent on water Population growth, agricultural demand and economic expansion Climatic pressures - Precipitation decreasing; Temperature increasing

Project Overview Aim: To develop a comprehensive spatial multidimensional framework to quantitatively assess water vulnerability in Western Australia’s Wheatbelt. Approach: Use a GIS to incorporate multiple spatial socioeconomic and environmental datasets to spatially assess water vulnerability for 2001, 2006 and 2011.

Measuring Water Vulnerability International: Water Vulnerability Index (Sullivan et al. 2006, 2008, 2010; Sullivan 2011; Knoesen 2009)

Measuring Water Vulnerability

Measuring Water Resource Issues Australia/Western Australia: Water Futures for Western Australia 2008 ‐ 2030 (2008) - climate scenarios – water use and demand by demand region CSIRO/BoM/BRS Australian Water Availability Project (2008) - monitor the state and trend of the terrestrial water balance of Australia CSIRO South-West Western Australia Sustainable Yields Project (2009) - climate scenarios – gaps between yield and demand NCCARF Resilience and Water Scarcity in Two Outback Cities (2010) - qualitative assessment – challenge of water security and sustainability

Wheatbelt Water Supply Scheme – Aquifer – Precipitation – Surface – Desalination

Wheatbelt Water Supply Pressures Literature: - Climate change - Reduced rain/increased temp - Salinisation Workshop: - Failure to innovate - Aging Infrastructure

Wheatbelt Water Demand Households – Agriculture - Industry

Wheatbelt Water Demand Pressures Literature: - Population - Agricultural/Livestock - Industry - Temp/Evap Workshop: - Failure to innovate - Loss of most productive land

Water Futures of Western Australia Department of Water 2008 Ground Water Use 2008 (GL) Surface Water Use 2008 (GL)

Water vulnerability framework

Framework validation Climate - temperature - evaporation Resource - precipitation - desalination - groundwater - quality Storage - natural - human-made Delivery - scheme - private Climate - temperature - evaporation Human - infrastructure - residential - recreation Env. demand - competes with human needs Industry - mining - construction Agriculture - irrigation - spraying - stock

Measuring Water Vulnerability Water System Vulnerability (WSV) is determined by: WSV = WSSV + WSDV Water System Supply Vulnerability (WSSV): precipitation characteristics; sustainability of aquifer(s); density and capacity of scheme; climate forcing factor Water System Demand Vulnerability (WSDV): evapotranspiration; temperature; livestock density; land under cropping; population factors; emp. in water-dep. sectors; distance to scheme; growth factors; climate forcing factor

Measuring Water Vulnerability Water System Vulnerability (WSV): WSV = WSSV + WSDV Water System Supply Vulnerability (WSSV): WSSV = (SC * S D ) + (Y r * a) + (CV * V) Water System Demand Vulnerability (WSDV): WSDV = h ((g P (P) + (g L (A L ) + g C (A C ))) + g I (I) where: P = P S * P A * P D * P E Variable DescriptionNotes SUPPLY SDSD Density of pipelinesInverted SCScheme capacity Y r *aSustainable yield of aquifer * %area of SLA covered by the aquiferInverted CVCoefficient of variation of mean annual precipitation VDifference between annual precipitation and long-term meanInverted WSSVWater System Supply Vulnerability DEMAND hTotal evaporative demand * Variation in temperature from long-term mean PSPS Average Euclidean distance to pipeline PAPA Average Euclidean distance to aquifer PDPD Population density PEPE SIEFA score of disadvantage ALAL Density of livestock ACAC Percentage of cleared land under cropping IPercentage of SLA population employed in water-dependent industries gPgP Population growth gLgL Livestock growth gCgC Cropping area growth gIgI Industrial growth WSDVWater System Demand Vulnerability WATER VULNERABILITY WSVWater System Vulnerability

Changes in Supply Vulnerability

Changes in Demand Vulnerability

Changes in Water Vulnerability

Influences on Water Vulnerability

Western Australia’s Wheatbelt Informative planning for Wheatbelt > Wheatbelt water strategy (action required) > Targeting development of technology to reduce demand vulnerability e.g. scheme expansion and supply vulnerability e.g. desalination capacity Application to other regions in WA Thank You

Measuring Water Vulnerability Water System Vulnerability (WSV): WSV = WSSV + WSDV Water System Supply Vulnerability (WSSV): WSSV = (SC * S D ) + (Y r * a) + (CV * V) Water System Demand Vulnerability (WSDV): WSDV = h ((g P (P) + (g L (A L ) + g C (A C ))) + g I (I) where: P = P S * P A * P D * P E SC = C + D + Y where C is the surplus capacity of total water supply and D is the total dam carryover, calculated as D = (Total Storage – Carryover storage – Inflow) / Total Storage c P is an optional climate forcing factor to project future WSSV based upon a projected precipitation change factor.