Rockingham—Stakehill groundwater management plan Looking after all our water needs Department of Water Water resource allocation planning series Report no. 23 November 2008 Department of Water 168 St Georges Terrace Perth Western Australia 6000 Telephone +61 8 6364 7600 Facsimile +61 8 6364 7601 www.water.wa.gov.au © Government of Western Australia 2008 November 2008 This work is copyright. You may download, display, print and reproduce this material in unaltered form only (retaining this notice) for your personal, non-commercial use or use within your organisation. Apart from any use as permitted under the Copyright Act 1968, all other rights are reserved. Requests and inquiries concerning reproduction and rights should be addressed to the Department of Water. ISSN 1327-8428 (print) ISSN 1834-2620 (online) ISBN 978-1-921549-01-4 (print) ISBN 978-1-921549-02-1 (online) For more information about this report, contact: Kwinana Peel Region Department of Water PO Box 454 Kwinana WA 6966 Telephone +61 8 9411 1788 Facsimile +61 8 9419 5897 Rockingham–Stakehill groundwater management plan Contents Summary ....................................................................................................................vi 1 Introduction..............................................................................................................1 1.1 Purpose............................................................................................................................1 1.2 Objectives ........................................................................................................................1 1.3 The plan area...................................................................................................................1 1.3.1 Location ..................................................................................................................................1 1.3.2 Proclamation of the plan area.................................................................................................3 1.3.3 The plan boundary..................................................................................................................3 1.4 Groundwater resource overview ......................................................................................6 1.5 The plan’s socio-economic environment ..........................................................................6 1.6 Water allocation in Western Australia ..............................................................................8 1.6.1 Principles ................................................................................................................................8 1.7 Legislative and policy framework ...................................................................................10 1.7.1 The role of the Department of Water ....................................................................................10 1.7.2 Rights in Water and Irrigation Act 1914 ................................................................................10 1.7.3 Water reform.........................................................................................................................10 2 Environmental considerations ...............................................................................11 2.1 Sustainable use of water................................................................................................11 2.2 Environmental water provisions .....................................................................................11 2.3 Ecological considerations...............................................................................................12 2.3.1 Groundwater-dependent ecosystems ...................................................................................12 2.3.2 Future work to set ecological water requirements.................................................................18 2.4 Social values..................................................................................................................18 2.5 Aboriginal cultural values ...............................................................................................20 2.5.1 Native Title............................................................................................................................20 2.6 Water quality ..................................................................................................................21 2.6.1 Acid sulfate soils ...................................................................................................................21 2.6.2 Seawater interface................................................................................................................22 3 Groundwater use...................................................................................................23 3.1 Existing groundwater use...............................................................................................23 3.2 Subarea water use.........................................................................................................26 3.3 Public drinking-water source areas ................................................................................28 3.4 Future use......................................................................................................................28 3.4.1 Potential water supplies........................................................................................................28 3.4.2 Future demand .....................................................................................................................28 4 Status of the groundwater resources.....................................................................30 4.1 Monitoring the resource .................................................................................................30 4.2 Monitoring groundwater levels .......................................................................................32 4.2.1 Monitoring program...............................................................................................................32 4.2.2 Superficial Aquifer.................................................................................................................32 4.2.3 Rockingham Sand Aquifer ....................................................................................................35 4.2.4 Leederville Aquifer ................................................................................................................36 4.2.5 Yarragadee Aquifer...............................................................................................................37 4.3 Monitoring groundwater quality ......................................................................................38 4.3.1 Monitoring program...............................................................................................................38 4.3.2 Superficial Aquifer.................................................................................................................38 4.3.3 Rockingham Sand Aquifer ....................................................................................................39 Department of Water iii WRAP 23 4.3.4 Leederville Aquifer ................................................................................................................39 4.3.5 Yarragadee Aquifer...............................................................................................................39 4.4 Monitoring groundwater use...........................................................................................40 4.4.1 Licensed allocation ...............................................................................................................40 4.4.2 Authorised unlicensed use....................................................................................................41 4.5 Future monitoring...........................................................................................................42 4.6 Groundwater modelling ..................................................................................................42 5 Groundwater allocation .........................................................................................43 5.1 Water allocation .............................................................................................................43 5.2 Groundwater allocation in the Rockingham—Stakehill area ..........................................43 5.2.1 Department position..............................................................................................................43 5.2.2 Approach to setting allocation limits......................................................................................43 5.2.3 Groundwater allocation in the unconfined aquifers ...............................................................44 5.2.4 Groundwater allocation in the confined aquifers...................................................................45 5.3 Impacts of climate variability on water allocation............................................................46 6 Allocation principles and licensing considerations.................................................47 6.1 Allocation approach........................................................................................................47 6.2 Allocation policies...........................................................................................................48