Project goal: 

We upgraded the Vasse Diversion Drain to increase flood protection in Busselton.

Status:

Complete 

Delivery Date:

Winter 2021

We will manage 15ha of land surrounding the drain for up to 10 years and plant more than 130,000 seedlings to offset any vegetation clearing necessary for construction, as per the environmental approvals for the project.

We upgraded the Vasse Diversion Drain to increase flood protection in Busselton.

Floods have continued to affect the Busselton community since the drain was built in the 1920’s, and although we have been making smaller modifications to the Busselton drainage system to mitigate flooding, these options had run out.

The Vasse Diversion Drain starts just North of the Busselton Golf Course (refer to map under Document Library) and extends for around 6.3 km north to the ocean at Geographe Bay. It diverts water from the Vasse and Sabina rivers to prevent them overflowing and flooding Busselton.

In November 2000, State Cabinet accepted a proposal from the Busselton Flood Management Steering Committee to ensure the Busselton community be protected from 1 in 100 year rainfall events. This plan included the construction of large compensating basins and reconstructing the banks of the Vasse Diversion Drain.

Since then, we have been working towards this goal, having completed the construction of three compensating basins and reviews of local drainage needs. We have now determined the essential next step is to increase the capacity of the Vasse Diversion Drain while reconstructing the levee banks and building an overflow structure where the drain meets the Vasse River.

We listened

Consultation has concluded.

In December 2019, we set up pop-up project information booths. We spoke to over 100 residents to better understand how people use the drain and any concerns they had about construction or eventual changes to the drain, before finalising our design and construction plan.

We listened to this community feedback and have developed a plan with solutions and strategies. We also shared this plan at our our pop-up project information booths in February 2020 and continued our discussions with the community to refine it and create more opportunities to work with local groups and experts.

In September 2020, we again invited the community along to our project information booths, and provided an update on our environmental management plans and the outcomes of our environmental approvals.

Over the course of this consultation, we had face to face conversations with over 15 local groups and more than 200 community members to help inform how the project will be delivered.

The scope of the upgrade involves widening the levee banks to increase the drain’s capacity and improve the structural integrity of the banks, which were originally built with old technology in the 1920's. It also involves building a spillway structure at the Southern end of the drain in Bovell which will receive any overflow from the drain and divert it to the Lower Vasse River. 

The Vasse Diversion Drain is essential to protect Busselton from flooding. This project will ensure the drain is able to handle up to 1 in 100 year rainfall events and protect property and the surrounding environment from flooding. At the completion of the project, the drain will be able to hold more water, move more water and the banks will be stronger to ensure the water is contained.

Despite recent improvements, Busselton’s current drainage system does not protect the area against a 1 in 100 year rainfall event. Since the original construction of the drain, large residential areas have been developed alongside the drain, causing less open soil that can hold water (after rain) and increased run-off. These conditions increase the risk of flooding.

The phrase “1 in 100 year event” refers to the estimated probability of an event happening in any given year. A 100 year event has a 1 percent chance (1 in 100 chance) of occurring in any given year. Therefore, this does not mean this kind of rainfall will occur every 100 years, or that it can only occur once in 100 years. However, it helps us place a particular weather event in the context of similar events.

Busselton, being very flat, is particularly prone to flooding and has experienced such events in 1963, 1964, 1965, 1986, 1997 and 1999.

This project requires a small amount of tree clearing along the drain to allow us to make the drain wider. We have been working with Department of Water and Environmental Regulation and other flora and fauna experts to assess and mitigate any impacts to threatened species in the area, such as: 

  • Pseudocheirus occidentalis (Western Ringtail Possum) – Vulnerable (Federal and State)
  • Calyptorhynchus baudinii (Baudin’s Cockatoo) – Vulnerable (Federal and State)
  • Calyptorhynchus latirostri (Carnaby’s Black Cockatoo) – Endangered (Federal and State)
  • Calyptorhynchus banksia naso (Forest Red-tailed Black Cockatoo) – Vulnerable (Federal and State)
  • Caladenia procera (Carbunup King Spider Orchid) – Critically Endangered (Federal and State)
  • Westralunio carteri (Carter’s Freshwater Mussel) – Vulnerable (State)

Various management plans to protect local populations are being developed for the project. 
This project is currently seeking environmental approvals through our regulators.

There are dedicated plans that have been approved by the City for dust suppression and noise management during construction.

Owners of properties affected by machinery vibrations were invited to take part in a property survey before construction began. 

There will be increased vehicle movements as machinery and materials are moved in and out of the drain. Traffic management plans are put in place to ensure this is done safely.

The levee banks are temporarily closed during construction to ensure everyone's safety. Once upgrades are complete, pedestrian access to the levee banks will still be possible.

The pedestrian bridges over the drain between Glenmeer Ramble and College Ave and between Queen Elizabeth Ave and Moore St will need to be closed from 23 November - mid-April 2021.

A temporary footpath detour from Moore St to Bussell Hwy is in place for the pedestrian bridge connecting Queen Elizabeth Ave to Moore St and Carter St.

Aside from being wider, earthworks will mean grass covering the drain will no longer be visible. We are working with specialists and the community to revegetate the area and the surrounds, ensuring plants selected are suitable to maintain bank stabilisation, keep fire risk low and restore ecological function. 

To ensure tree roots do not compromise the structure of the drain, native shallow rooted plants and grasses will be used near to the drain.

The revegetation plan for the area is available in the Document Library.

Now dissolved, the Busselton Flood Management Steering Committee was formed in 1997 following a major flood event in Busselton. It comprised representatives from (the then) Office of Water Regulation (now Department of Water and Environmental Regulation)(DWER), Department of Agriculture (now Department of Primary Industries and Regional Development), Department of Conservation and Land Management (now Department of Biodiversity, Conservation and Attractions)(DBCA), Water and Rivers Commission (now merged with DWER), GeoCatch, Shire (now City) of Busselton and Water Corporation.

The following supplementary documents are available on request. 

Please contact us via the contact details provided for further assistance.  

Environmental approvals - Permits and Licences

  • EPBC 2017-7932 - Final decision - Notice with conditions from DAWE (739 KB) (pdf)
  • EPBC 2017-7932 - Final decision - Letter from DAWE (91.2 KB) (pdf)
  • 8191/1 Clearing Permit Granted - Letter from DWER (512 KB) (pdf)
  • 8191/1 Clearing Permit Decision Report - DWER (2.3 MB) (pdf)
  • Purpose Permit (667 KB) (pdf)
  • Clearing Permit PLAN A (5.91 MB) (pdf)
  • Clearing Permit PLAN B (2.35 MB) (pdf)
  • Clearing Permit PLAN C (4.61 MB) (pdf)
  • Clearing Permit PLAN D (3.67 MB) (pdf)
  • Clearing Permit PLAN E (4.89 MB) (pdf)
  • DWER Water Licence - GWL204992 (82.5 KB) (PDF)
  • DWER Water Licence - CAW204993 (82.2 KB) (PDF)

Environmental surveys and supporting information

  • Hydrological Review 2013 (16.5 MB) (pdf)
  • Revegetation Plan Draft - Vasse Diversion Drain Upgrade (23.4 MB) (pdf)
  • Vasse Diversion Drain Upgrade Revegetation Plan – Baseline Vegetation Monitoring Report - February 2021.pdf (19.8 MB) (pdf)
  • Mussel Relocation and Monitoring Report- December 2020.pdf (917 KB) (pdf)
  • Clearing permit submission - Variation 2 with Supporting Documents (96.8 MB) (pdf)
  • Acid Sulfate Soils Investigation 2009 (362 KB) (pdf)
  • Historic clearing extents - Aerial 1954 (1.23 MB) (pdf)
  • Historic clearing extents – Aerial 1970 (1.23 MB) (pdf)
  • Historic clearing extents - Aerial 1996 (1.23 MB) (pdf)
  • Targeted Monosulfidic Black Ooze (MBO) survey 2019 (6.21 MB) (PDF)
  • Surveys and Data - Possums (2.49 MB) (pdf)
  • Targeted Fauna Survey (WR Possums) 2019 (2.07 MB) (pdf)
  • Surveys and Data - Mussels (2.5 MB) (pdf)
  • Fauna Shelters (508 KB) (pdf)
  • Possum Bridges (508 KB) (pdf)
  • Phytophthora Dieback Risk Assessment (Great Southern BioLogic, 2020) (1.03 MB) (pdf)
  • Monosulfidic Black Ooze Reconnaissance Survey (RPS 2020) (11.1 MB) (pdf)
  • Targeted Orchid Survey – Dixon 2020, Survey Date 14 September 2020 (8.06 MB) (pdf)
  • Targeted Fauna Survey (Mussels) 2019 - Beatty et al (792 KB) (pdf)
  • Targeted Fauna Survey (Mussels) 2019 - GHD (5.62 MB) (PDF)
  • Targeted Fauna Survey (Mussels) 2008 (1.28 MB) (PDF)
  • Targeted Fauna Survey (Mussels) 2006 (348 KB) (PDF)
  • Surveys and Data - Cockatoos (3.07 MB) (pdf)
  • Targeted Fauna Survey (Black Cockatoos) 2019 (521 KB) (pdf)
  • Surveys and Data - Conospermum (2.86 MB) (pdf)
  • Targeted Flora Survey (Conospermum) 2019 (4.96 MB) (pdf)
  • Conospermum Genetic Testing 2019 (1.9 MB) (pdf)
  • Fauna, Flora and Vegetation Survey 2017a (15.6 MB) (pdf)
  • Fauna, Flora and Vegetation Survey 2017b (15 MB) (pdf)
  • Fauna, Flora and Vegetation Survey 2009 (12.7 MB) (PDF)
  • Targeted Flora Survey (Orchids) 2017c (1.13 MB) (PDF)

Management plans and reports

  • Annual Compliance Report June 2022 (172 MB) (pdf)
  • Annual Compliance Report June 2021 (68.5 MB) (pdf)
  • Fauna relocation and monitoring report - October 2020 to January 2021 (22.6 MB) (pdf)
  • Construction Environmental Management Framework Oct 2020 (66.4 MB) (pdf)
  • ESA Fence Installation Construction Environmental Management Plan 201012 (Tranen 2020b) (1.37 MB) (pdf)
  • Fauna Management Plan (Bamford Consulting Ecologists, 2020) (4.39 MB) (pdf)
  • Phytophthora Dieback Risk Assessment (Great Southern BioLogic, 2020) (1.03 MB) (pdf)
  • Revegetation Management Plan (Tranen Revegetation Southwest, 2020) (23 MB) (pdf)
  • Waste Characterisation Levee Soils and Sediments (RPS 2020b) (22 MB) (pdf)
  • Water Quality Monitoring and Management Plan (IndoPacific 2020b) (1.87 MB) (pdf)
  • Westralunio carteri (Carter's Freshwater Mussel) Relocation Management Plan (IndoPacific 2020a) (1.84 MB) (pdf)
  • Acid Sulfate Soils and Dewatering Management Plan - Report (43.3 MB) (pdf)

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Contact us

Alyce Nehme (Community Engagement Advisor)

Phone icon (08) 6330 6523

Email icon alyce.nehme@watercorporation.com.au