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Alkimos Seawater Desalination Plant

Project
Proponent: 
Water Corporation
Proposal description: 

The Western Australian Water Corporation is proposing to construct the Alkimos Seawater Desalination Plant (ASDP) as part of Perth’s Integrated Water Supply Scheme which aims to provide additional sources of drinking water to supplement the existing metropolitan water supply.

The ASDP Proposal will be located within the Alkimos Water Precinct (Lot 1050 Marmion Avenue), approximately 40 km north of the Perth, within the northwest corridor, north of Quinns Rock beach and south of Yanchep beach.

ASDP will be developed in four stages (each with a capacity to supply 25 GL) with the timing of each stage based on actual growth in water demand, potential groundwater allocation reduction, actual streamflow conditions and timing of other source option development (e.g. construction of the proposed PSDP2 at Kwinana).

The Proposal requires the installation of two seawater intakes and two seawater return outlets (approximately 4 km offshore) to enable the discharge of return seawater (brine) to the marine environment.

Proposal Content Document: 
PDF icon Proposal Content Document March 2025.pdf
Assessment Number: 
2210
Region: 
Perth
Referred under EP Act: 
s38
Industry sector: 
Infrastructure
Last updated: 
March 13, 2025
Current Status: 
Ministerial Statement published
Ministerial Statement published
1. Referral
Comment on this referral: 
Alkimos Seawater Desalination Plant
Comment period: 
Wednesday, 15 May, 2019 to Tuesday, 21 May, 2019
Referral documentation: 
PDF icon Referral Form
PDF icon Environmental Review Document Part A
PDF icon Environmental Review Document Part B
PDF icon Environmental Review Document Part C
PDF icon Environmental Review Document Part D
PDF icon Environmental Review Document Part E
PDF icon Environmental Review Document Part F
PDF icon Environmental Review Document Part G
PDF icon Environmental Review Document Part H
PDF icon Environmental Review Document Part I
PDF icon Environmental Review Document Part J
PDF icon Environmental Review Document Part K
PDF icon Environmental Review Document Part L
PDF icon Environmental Review Document Part M
PDF icon Environmental Review Document Part N
PDF icon 3. App_B_Alkimos_Hydrodynamic_Modelling_Scenario_Report.pdf
PDF icon 4. App_C_Alkimos Hydrodynamic_Modelling_Calibration_Report_Part1.pdf
PDF icon 4. App_C_Alkimos Hydrodynamic_Modelling_Calibration_Report_Part2.pdf
PDF icon 5. App_D_Alkimos_Peer_Review_Panel_Final Report.pdf
PDF icon 6. App_E_EPBC Protected Matters Report.pdf
PDF icon 7. App_F_AECOM_Flora_Vegetation_Fauna_Assessment_Spring_2017.PDF
PDF icon 8. App_G_AECOM_Ecological_Assessment_Alkimos_SDP_Pipeline_Integration.pdf
PDF icon 9. App_H_Strategen_Alkimos_Flora_Vegetation_Survey_Spring_2016_Part1.pdf
PDF icon 9. App_H_Strategen_Alkimos_Flora_Vegetation_Survey_Spring_2016_Part2.pdf
PDF icon 9. App_H_Strategen_Alkimos_Flora_Vegetation_Survey_Spring_2016_Part 3.pdf
PDF icon 10. App_I_Ecoscape_Eglinton_Groundwater_Investigations_Flora_Vegetation_Fauna_Dieback_Survey_Site2.PDF
PDF icon 11. App_J_Bamford_Alkimos_Wastewater_Treatment_Plant_Fauna_Assessment.PDF
2. Decision on whether to assess this proposal
Chair's Determination: 
Assess - Public Environmental Review
Extract of determination: 
PDF icon Alkimos Seawater Desalination Plant and associated pipeline to Wanneroo Reservoir
Preliminary Environmental Factors: 
Social Surroundings
Benthic Communities and Habitats
Marine Environmental Quality
Marine Fauna
Flora and Vegetation
Landforms
Terrestrial Fauna
Date published: 
Monday, 17 June, 2019
3. Assessment
Scoping
Environmental scoping document: 
PDF icon CMS17602-Approved ESD-080520.PDF
Approved: 
Friday, 8 May, 2020
Environmental Review
Public submissions: 
Wednesday, 28 September, 2022 to Tuesday, 25 October, 2022
Make a submission: 
Alkimos Seawater Desalination Plant - Public Environmental Review
Environmental Review documentation: 
PDF icon Alkimos SDP - Public Environmental Review Document_Rev 6_19 September.pdf
PDF icon Alkimos SDP - Proposal Content Document_20-9-22.pdf
PDF icon Appendix A - Stakeholder Consultation Summary.pdf
PDF icon Appendix B - Environment Policy.pdf
PDF icon Appendix C - Alkimos Seawater Desalination Plant Marine Noise Study.pdf
PDF icon Appendix D - Alkimos Hydrodynamic Modelling_Scenario Report (20632738) .pdf
PDF icon Appendix E - DHI_Alkimos_Hydrodynamic_Modelling_Calibration_Report (1).pdf
PDF icon Appendix F - Alkimos_Peer_Review_Panel_Final_Report.pdf
PDF icon Appendix G - Construction Marine Environmental Management Plan .pdf
PDF icon Appendix H - Commissioning & Operations Marine Environmental Management Plan .pdf
PDF icon Appendix I - EPBC_Protected_Matters_Search_-_Alkimos_WWTP_5km_-_14th_September_2017.pdf
PDF icon Appendix J - Alkimos SDP Flora and Vegetation Consolidation Report REDUCED.pdf
PDF icon Appendix K - Alkimos SDP Terrestrial Fauna Consolidation Report.pdf
PDF icon Appendix L - Alkimos_SDP_Social_Impact_Assessement_Sept_2018_(19561732) .pdf
PDF icon Appendix M - Alkimos SDP Proposed Greenhouse Gas Management Plan_Sept 2022.pdf
PDF icon Appendix N - Alkimos Seawater Desalination Plant, Environmental Approvals Inputs (Jacobs, 2020).pdf
PDF icon Appendix O - Environmental Noise Assessment, Proposed Alkimos Desalination Plant, Revised Topography.pdf
PDF icon Appendix P - Alkimos SDP - Terrestrial Construction Environmental Framework .pdf
PDF icon Appendix Q - Alkimos_Water Precinct Environmental Management Plan.pdf
PDF icon Appendix R - Alkimos SDP Aboriginal Heritage Survey - Summary.pdf
PDF icon Appendix S - Alkimos Offsets Strategy - Sept 22.pdf
PDF icon Appendix T - Alkimos Options Assessment.pdf
PDF icon Appendix U - Summary of Potential Discharge Plume Interactions.pdf
Date Published (Environmental Review documentation): 
September 28, 2022
Proponent response to submissions: 
PDF icon AA_RTS Submission CoverLet - February 2023 Assessment 2210_Water Corporation (Feb).pdf
PDF icon Attachment 1 - ASDP RTS to EPAS comments (Feb).pdf
PDF icon Attachment 2 - ASDP RTS to Public and Agency_Other Responses (April).pdf
PDF icon Attachment 3 - ASDP - RTS Supporting Document (April).pdf
PDF icon Attachment A - ADSP_Construction_MEMP_Rev3_20230120.pdf
PDF icon Attachment B - ADSP_Commissioning & Ops_MEMP_Rev3_20230120.pdf
PDF icon Attachment C - Letter from DPLH re MS722 .pdf
PDF icon Attachment D - Alkimos Offsets Strategy - Rev4 (April).pdf
PDF icon Attachment E1 - Alkimos SDP - Terrestrial Construction Environmental Management Plan Rev 4 (April).pdf
PDF icon Attachment E2 - Alkimos Water Precinct - Environmental Management Plan (April).pdf
PDF icon Attachment F - BC Foraging Habitat Assessment.pdf
PDF icon Attachment G - ASDP Greenhouse Gas Management Plan Rev 3 Feb 2023.pdf
PDF icon Attachment H - Alkimos Hydrodynamic Modelling – Phase 2b Scenario Report.pdf
PDF icon Attachment I - Plant Layout MV08-017-003-01-EPA.pdf
PDF icon Attachment J - Aboriginal Heritage Report - Exec Summary.pdf
PDF icon Attachment K1_Anders_F&V_report East Wanneroo V2.0_2023.pdf
PDF icon Attachment K2_Biologic - Mariginiup Road and Old Yanchep Road_Report V1_2023.pdf
PDF icon Attachment K3_GHD - Pipeline route - FCT determination_2023.pdf
PDF icon Attachment K4_SLR - Alkimos Pipeline Targeted Flora Report_2023.pdf
PDF icon Attachment K5_SLR - Alkimos SDP Black Cockatoo Tree Survey Hollow Inspection_2023.pdf
PDF icon Attachment K6_SLR 360 Environmental - ASDP pipeline Alternative Route Survey_2022.pdf
PDF icon Fig_5A-Flora and Vegetation survey effort.pdf
PDF icon Fig_6A-Terrestrial Fauna survey effort.pdf
PDF icon Fig_9-1_VegetationUnits_20221221_1a.pdf
PDF icon Fig_9-1_VegetationUnits_20221221_2b.pdf
PDF icon Fig_9-1_VegetationUnits_20221221_3c.pdf
PDF icon Fig_9-1_VegetationUnits_20221221_6f.pdf
PDF icon Fig_9-1_VegetationUnits_Portrait_20221221_4d.pdf
PDF icon Fig_9-1_VegetationUnits_Portrait_20221221_5e.pdf
PDF icon Fig_9-1_VegetationUnits_Portrait_20221221_7g.pdf
PDF icon Fig_9-1_VegetationUnits_Portrait_20221221_8h.pdf
PDF icon Fig_9-2_VegetationCond_20221222_1.pdf
PDF icon Fig_9-2_VegetationCond_20221222_2.pdf
PDF icon Fig_9-2_VegetationCond_20221222_3.pdf
PDF icon Fig_9-2_VegetationCond_20221222_6.pdf
PDF icon Fig_9-2_VegetationCond_Portrait_20221221_4.pdf
PDF icon Fig_9-2_VegetationCond_Portrait_20221221_5.pdf
PDF icon Fig_9-2_VegetationCond_Portrait_20221221_7.pdf
PDF icon Fig_9-2_VegetationCond_Portrait_20221221_8.pdf
PDF icon Fig_9-3a to 9-3h .pdf
PDF icon Fig_9-4a to 9-4h .pdf
PDF icon Fig_9-5a to 9-5h.pdf
PDF icon SLR 360 Env_Alkimos Transmission Line Vegetation Assessment_Rev3 (May 2023).pdf
Date published (Proponent response to submissions): 
May 8, 2023
Minor or preliminary work under s. 41A(3)
s. 41A(3) notice: 
PDF icon CMS17602 - S41A(3) Notice - 200921.pdf
Date of approval s. 41A(3): 
Monday, 20 September, 2021
Change to proposal during assessment under s. 43A
s. 43A notice: 
PDF icon CMS17602 - S43A - 060421.pdf
PDF icon CMS17602 - S43A Notice - 200921.pdf
PDF icon CMS17602 - S43A Notice - 070323.pdf
Date of approval s. 43A: 
Tue, 07/03/2023
4. EPA Report on assessment
EPA Report Number: 
1739
EPA Report: 
PDF icon EPA Report 1739 - Alkimos Seawater Desalination Plant - Assessment report.pdf
Key Environmental Factors: 
Social Surroundings
Benthic Communities and Habitats
Marine Environmental Quality
Marine Fauna
Flora and Vegetation
Landforms
Terrestrial Fauna
Date published: 
Wednesday, 24 May, 2023
Appeals close: 
Wednesday, 14 June, 2023
5. Decision on proposal and implementation of proposal
Ministerial Statement
Date of approval: 
Thursday, 10 August, 2023
Ministerial Statement: 
PDF icon Statement 1207.pdf
Post-assessment changes
s. 45C amendments: 

Attachment 1 to Statement 1207 - Increase the proposal development envelope from 141.6 hectares (ha) to 142.73 ha. Decrease the marine development envelope from 11.45 ha to 11.42 ha. Increase the terrestrial development envelope from 130.15 ha to 131.31 ha. Proponent updates to the ‘Proposal Content Document’, as amended by the change to proposal approved under s.43A on 7 March 2023 to reflect the amendment approved under s.45C on 17 April 2024.Changes to conditions to reflect the change in the authorised extent of impacts. Change to conditions approved under s45C on 17 April 2024

Attachment 2 to Statement 1207 -  Increase the proposal development envelope from 142.73 hectares (ha) to 195.74 ha. Increase the terrestrial development envelope from 131.31 ha to 184.32 ha. Decrease the clearing of native vegetation from 51.20 ha to no more than 50.95 ha. Changes to conditions to reflect the change in the authorised extent of impacts to flora and vegetation, terrestrial fauna, and landform environmental values. Remove condition B1-2 and Figure 3 relating to the requirement for additional survey for Banksia attenuata woodlands over species rich dense shrublands (floristic community type 20a) threatened ecological community. Change to conditions approved under s45C on 21 January 2025.

Attachment 3 to Statement 1207 -  Increase the marine development envelope from 11.42 hectares (ha) to 77.79 ha.
• Change the outlet design from two 7 metre (m) diameter rosette diffusers to a single linear diffuser
• Change the definition of the Low Ecological Protection Area (LEPA) to accommodate the proposed change to the diffuser
• Change condition A1 to reduce the maximum salinity limit from 75,200 milligram per litre (mg/L) to 68,000 mg/L
• Decrease the maximum irreversible loss of benthic communities and habitats from 0.13 ha to 0.10 ha
• Increase the maximum disturbance to benthic communities and habitats from 8.39 ha to 8.68 ha
• Change the proposal description.. Change to conditions approved under s45C on 13 March 2025.

Attachments: 
PDF icon Summary of reasons.pdf
PDF icon Attachment 2 - Notice and Summary of Reasons.pdf
PDF icon Attachment 3 - Notice and Summary of Reasons.pdf
Date of approval s. 45C: 
Wednesday, 17 April, 2024
Tuesday, 21 January, 2025
Thursday, 13 March, 2025

Source URL:https://www.epa.wa.gov.au/proposals/alkimos-seawater-desalination-plant