Groundwater as a “drought reserve” in a drying climate Presentation to the University of Melbourne Law School Workshop on Water Governance for Resilience Alex Gardner Faculty of Law, UWA 25/09/14

Overview: Reforms for groundwater drought reserve Orienting South West Western Australia National water policy reforms Planning for climate change adaptation Entitlement holders saving water Conclusions - groundwater based system

1. Orienting South West WA Surface water yield 1/4 of 1970 Groundwater makes up around three quarters of water use Total groundwater use around 850GL/yr (2009 estimate) Self-supply for gardens, public open space, horticulture, mining, industry is around 700GL/yr important for public water supply (~150GL/yr and 40% of IWSS) New alternative sources: Desalination 150 GL/yr (from 2006) Recycled water; GWR  28 GL/yr Demand management environmental water allocations frequently breached Source: CSIRO 2009 25/09/14 3

Rainfall trend since 1987 - predicted vs actual 4

Public water supply strategy SUPPLY AND DEMAND FOR THE INTEGRATED SCHEME (IWSS) 350 Groundwater Security Strategy 300 Southern Seawater Desalination Plant Perth Seawater Desalination Plant 250 Groundwater Supply Surface Water (including trade) GIGALITRES 200 150 100 50 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 YEAR 1990 1995 2000 2005 2010 2015 2020 Source: Water Corporation (2013)

Groundwater resources declining Gnangara Superficial Gnangara Confined SW Ramsar wetland: declining water table impacts water quality

Gnangara Groundwater System Rainfall Superficial aquifer well Confined aquifer well Bassendean Sand River Guildford Clay ial Confining Bed au t l F ville aquifer ng arli ed D Coastal Limestone Wetland Indian Ocean Superfic aquifer Caves Leeder Confining B Confining Bed Yarragadee aquifer 25/09/14

2. National Water Policy Reforms Current Law (since 2001) Landholder eligibility to hold licence No statutory plans or consumptive pool – non-statutory allocation limits 10 yr licences with tradable entitlements Entitlements = maximum annual volume Poor water accounting & enforcement Legal environmental water allocations under EIA law or water licence conditions National Water Initiative reforms proposed but constantly delayed since 2006: Statutory allocation limits and plans for consumptive pool(s) Tradable perpetual share entitlements Environmental water holder RiWI Act turns 100, 22 Sept 2014

3. Climate change and groundwater planning Currently no requirement in the RIWI Act to consider climate change risks in groundwater planning (cf Water Act 2007 (Cth)) In practice, limited use of climate change scenarios in non-statutory allocation plans This is changing - DoW has new GIS tool to produce ‘future climate’ scenarios for any part of WA, to be used in future water planning. 25/09/14 9

Law reform proposal: duty to address climate change The new water resource management legislation should require the Minister to consider climate change risks in the preparation of statutory water allocation plans and to address those risks in the plan provisions: for example, declining allocation limits over plan life zoning areas for no consumptive use, including by domestic bores 25/09/14 10

4. Groundwater as a ‘drought reserve’ Can groundwater be sustainably used as a drought reserve in a drying climate? What regulatory arrangements would best support this? Case study: groundwater as a drought reserve for the IWSS public water supply Regulatory options for entitlements saving water 30/07/14 11

The Variable Groundwater Extraction Rule (VGAR) for IWSS 25/09/14 12

Failure of the VGAR in a drying climate Problem: In a declining rainfall trend the VGAR results in sustained high groundwater abstraction, compounding the effects of low recharge on the groundwater system (DoW, 2013) DoW solution: 5 year, 110GL/yr average extraction for the Integrated Water Supply Scheme. 25/09/14 13

Groundwater as a ‘drought reserve’: - regulatory options for entitlements Entitlement holders have: carryover and borrowing rights in suitable aquifers compulsory ‘banking’ (eg 10% of entitlement) accessible only on ministerial declaration Department reserves water and auctions short term licences on ministerial declaration Independent water holder retains water entitlements in suitable aquifers that it auctions in extreme drought Managed Aquifer Recharge of recycled water should include a restoration share 26/09/14 14

Conclusions for a Groundwater based system Information challenges – especially modeling NWI reforms – they are not enough Long term water resources assessment and climate adaptation planning NWI flexibility of share entitlements with obligations to plan for climate change - statutory duties to model, zone and save Urban water supply – alternative sources Social and cultural values