Landslides “don't stop at our boundaries”: Knox Council zooms in on erosion risk to homeowners

Areas in Ferntree Gully, Upper Ferntree Gully and The Basin were flagged as potential landslip or mudslide risk zones.

Author

Matthew Sims
December 01, 2025

Knox Council will look into its own erosion risks on private properties and communities, following the Yarra Ranges Council’s proposed broadening of its erosion controls.

🏃 Just quickly…: An Erosion Management Overlay (otherwise known as an EMO) is a restriction placed on the planning requirements for properties looking to develop in areas seen to be at risk of a landslide or mudslide.

🪨 Like a rolling stone: Yarra Ranges Council recently proposed changes to its EMO mapping –  placing an additional 2,365 homes within the risk zones.

Those changes are currently waiting on the Planning Minister to be made final.

“Another hurdle”: How will Yarra Ranges’ proposed erosion overlays impact the housing market?

“It cuts down the appetite to live in these high-risk areas."

🗺️ New frontier: For homeowners in the Yarra Ranges, inclusion in a new EMO could mean they must get a geotechnical report before doing any building or earthworks – usually costing between $700 and $3,000 or more.

  • Other potential impacts could include rising insurance premiums, changes ot the ability to rebuild after damage, as well as a property’s sale value.

⁉️ Knox wheels in motion: On Monday December 24, Knox Council voted to make a submission to Yarra Ranges Council to highlight the potential risk posed to Knox communities by the new mapping.

  • Knox councillor Meagan Baker moved an alternative motion to also request council officers undertake a preliminary erosion risk assessment for areas in Knox. This would then be presented in a future report focused on the potential dangers of landslips and mudslides. 

  • The preliminary work would take place within existing budget resources. Further work would be subject to further decisions and budget allocations in the 2026/27 financial year.

Yarra Ranges Council’s new mapping highlighted potential locations which could be impacted by debris flows.

⛰️ Knox at risk? Councillor Baker said the new mapping outlined by Yarra Ranges showed there may be “clear implications” for areas in Ferntree Gully, Upper Ferntree Gully, Sassafras and The Basin, projecting these areas may be impacted if a landslide or mudslide occurs.

  • 🗣️ “These changes don’t just stop at our boundaries,” said Baker.

Image Credit: Bob Tan