Original Letter to Council Albert and Logan Flood Study 2025
Subject: URGENT for Special Meeting- Terms of Reference
Hi Mr Mayor,
I’m writing in relation to your request for review of the terms of reference.
I applaud an independent review of the data but for this to actually reflect the communities concerns, I suggest the following be reviewed, which are all within the scope of the Study.
1. Hydrologic Model Calibration – Five gauging stations couldn’t be calibrated due to poor data and tailwater effects. Reviewer must map affected areas, quantify uncertainty, recommend lower-confidence classification.
This is covered in Item 2 and 5 of the scope that I will table today.
2. Uncalibrated Lower Catchment – Models couldn’t be jointly calibrated in the lower Logan (Waterford, Beenleigh area) due to tidal and floodplain storage. Reviewer must identify affected suburbs, quantify error, and recommend whether mapping should be revised.
The review can identify error bounds (and this already identified in the scope). Feedback from residents has included river discharge (which is the behaviour of the river mouth) but I’m not sure of the extent that this goes to so I’ll ask the question for you.
3. Spot Calibration Validation – Reviewer must compare model predictions against actual historical flood events (gauge records, high-water marks, photos) at specific properties to verify accuracy.
This is included in the current scope (Item 7)
4. Uncertainty Communication – Reviewer must verify that flood mapping documents clearly state which areas have lower confidence and what error ranges exist. Current mapping likely doesn’t communicate these limits.
Error bounds are included in Item 10 (in relation to PDF), confidence in modelling and confirmation of the process in Item 1 and 2 and 6.
5. Data Remediation Plan – Reviewer must require a specific timeline and protocol for improving data quality, with trigger criteria for mapping updates as new information arrives.
This is outside the scope of a review of a flood study, those are policy positions for Council to consider through a different process.
Without addressing these concerns, the terms of reference developed by Megan and Daryl will never be perceived as actually independent and it could be implied was just an expensive rubber stamping exercise, with a pre-determined outcome.
Terms of reference