The Council chamber erupted in applause from the public gallery as councillors unanimously voted to defer adoption of the Middle Harbour Flood Study on Tuesday night, 18 August.
Councillors voted to defer adopting the updated map of flood areas, agreeing to an extended consultation period and up to 100 resident site visits, after a wave of residents’ complaints about the study’s consultation and notification process.
Many residents fear the flood prone classification on official mapping will drive up home insurance costs, and needlessly so.
The Forest Flood Alliance (FFA), representing residents across Belrose, Frenchs Forest, Killarney Heights, Forestville and Davidson, urged councillors not to adopt the study along with a 537-signature petition.
“We thank Councillors for deferring adoption of the Middle Harbour Flood Study, and thank the residents who came forward to share their experiences,” a spokesperson for FFA told Manly Observer.
“We look forward to working constructively with Council staff on the outstanding issues, including notification and consultation, and ground-truthing the model against Council’s actual drainage infrastructure.
“Our goal is fair and accurate flood mapping for the benefit of our community.”
The Middle Harbour Flood Study maps flood risk across roughly 2,600 hectares spanning Davidson, Forestville, Killarney Heights, and parts of Belrose and Frenchs Forest. It’s the first time most of this area has been formally assessed for flooding.
A flood study models how floodwater behaves in a particular catchment using different-sized storm events.
The study identified 718 properties within the Flood Planning Area (the area expected to flood in a “1 in 100 year” flood) and 1,439 within the Probable Maximum Flood (the worst-case flood that could conceivably happen at that location) zone.
What residents say went wrong
“The process surrounding the Middle Harbour Flood Study has failed to adequately inform, consult and listen to the residents who are directly affected by it,” Elizabeth Saunders, a member of the FFA told Council at the public forum.
The FFA said Council had promised any property identified in the study as “at risk” would get a letter, but hundreds claimed they didn’t. Instead, many say they found out about the study too late, or through discussions with neighbours or by reading posts on social media..
During Tuesday night’s meeting, Council staff said around 2,000 letters were sent to properties within the proposed flood-risk areas and the Have Your Say page received several thousand visits. They extended the exhibition period by two weeks when they found out about Australia Post delivery delays and received 85 formal submissions during the exhibition. They added a further wave of complaints arrived in the weeks before Council’s meeting.
Residents also questioned the modelling itself.
“[Many neighbours] were in shock that their homes could be classified as flood affected,” Ms Saunders added.
“Many having lived in these properties for decades, a lot since the suburb was first developed, and all having never experienced flooding.”
A case study cited by the FFA involves a stormwater pipe on Starkey Street, Killarney Heights, which the model represents as a sharp right-angle bend restricting water flow. Long-term residents say the pipe was replaced decades ago with a curved main specifically to fix an old flooding problem, and that the properties in question haven’t flooded since, including during a 2022 storm Council itself has described as a near 1-in-100-year event.
The FFA says it has documented similar mismatches, missing or misrepresented drains, and terrain-mapping errors, elsewhere in the catchment.
The group adds that the study’s final maps exclude many genuinely flood-prone homes.
Residents expressed concerns about their property incorrectly identified as flood prone due to the ramifications on property value, future development, and insurance premiums.
Consultation period extended
“The Middle Harbor Flood Study [is] a document of significant consequence for residents whose homes, livelihoods, and financial security may be directly affected by its findings,” Frenchs Forest Ward Greens councillor, Ethan Hrnjak, said as he moved an amendment to the original motion to adopt it.
“The amendment … seeks to ensure that the engagement process we rely on and that our community needs to trust is fair, complete, and procedurally sound.”
The amendment sought to extend the consultation by six weeks, re-notify all affected property owners, complete outstanding site inspection requests (estimated at 50 to 75) funding up to 100 in total, at a cost of about $40,000 (and other project timelines pushed back), and run additional one-on-one sessions with flood engineers at Glen Street Library.
“I’ve received numerous representations from residents who tell me that they were not notified that their properties had been identified as flood affected,” Narrabeen Ward Independent councillor, Vincent De Luca said as he seconded the amendment.
“[This study] can affect future development, renovations, property transactions, insurance exponentially, and potentially property values.
“If a property owner is going to have their property affected, reclassified through council’s planning information, I believe they deserve to be properly notified and given a meaningful opportunity to understand and respond to that classification.
“Meaningful consultation requires that people materially affected by decisions have a reasonable opportunity to know about it, understand it, and have their concerns considered.”
Councillors unanimously agreed to the amendment.
