The short answer. If you live up the Macleay from Kempsey, past
Willawarrin and Bellbrook, the study says your flood problem is mostly not water in the
house. It is being cut off. In all floods events the closure of low lying bridges in the
area and associated isolation for a number of days is the main concern.
The study, by
consultants WMAwater for the council and covering about 2,000 square kilometres of the
valley inside Kempsey Shire, is the first of its kind: in its own words, This study presents the first comprehensive flood study for the
catchment.
It is a draft for comment, not a decision. The council says it
has not yet been adopted by Council
and that publishing it does not, by itself,
change planning controls, development requirements or other Council policies.
Cut off before the river is in minor flood
The sharpest line in the report is about Bellbrook Bridge: At least 18 properties are
isolated in Elsinore and McKenzie Creek/Scrubby Creek areas when the Bellbrook Bridge closes
(this is at approximately 2.70m on the local gauge, not even a minor flood event).
The
next sentence covers Toorooka: the bridge also provides access for at least 45
properties, and these properties are potentially isolated if other local roads are
closed.
The report then lists ten bridges with their deck levels and the modelled flood level at
each, for floods from a 20% chance in any year up to the largest flood possible. It says the
comparison gives an indication of during what size event these roads are likely to be
first cut.
Laid side by side, the 20% flood, the most frequent one modelled, is above the
deck at eight of the ten.
Ten bridges against a flood with a 20% chance in any year
Deck level, then the modelled 20% flood level, metres above sea level (AHD)
The bigger floods reach the towns’ edges. In a 1% flood, the executive summary says,
Aldavilla becomes isolated as Sherwood Road is cut off in both directions, and the Kempsey
Airport is surrounded by floodwaters. In Bellbrook, a small community near Nulla Nulla Creek
is isolated.
It also says Breakout flows occur in the 1% AEP, inundating rural
properties, particularly in Aldavilla, and Dondingalong.
In the probable maximum flood,
the largest that could occur, the flood extent expands, significantly
inundating properties in Bellbrook, Willawarrin, Aldavilla, and many rural areas with depths
exceeding 5m.
How long the roads stay under
For anyone who has sat out a flood on the wrong side of a creek, the duration table is the useful one. It models a 1% flood (a 1% chance in any year) on the main river and counts how many hours in each low point goes under, and for how long. Three roads go first, about a day in, and stay under longest: Hickeys Creek Road for 147.5 hours, which is more than six days, Mungay Creek Road for 137.1 and Mines Road for 134.6. Armidale Road between Kempsey and Willawarrin, the road from Willawarrin to town, is cut late, 93.1 hours in, and stays under for 63.7 hours.
Road low points in a 1% flood
Hours from the start of the flood until the low point is under water, then hours under
| Road | Cut after (hours) | Under for (hours) |
|---|---|---|
| Hickeys Creek Road | 22.6 | 147.5 |
| Mungay Creek Road | 24.7 | 137.1 |
| Mines Road | 25.9 | 134.6 |
| Mooneba Road | 79.9 | 76.9 |
| Willi Willi Road, Temagog to Willi Willi | 86.6 | 70.7 |
| Armidale Road, Kempsey to Willawarrin | 93.1 | 63.7 |
| Sherwood Road | 81.8 | 57.6 |
| Armidale Road, Willawarrin to Bellbrook | 79.1 | 44.6 |
| Warbro Brook Road, halfway to Willi Willi | 73.5 | 35.6 |
| Toorooka Road | 89.7 | 33.2 |
| Dungay Creek Road to Wittitrin | 72.4 | 25.7 |
| Armidale Road, Bellbrook to Comara | 90.9 | 21.5 |
| Aboriginal Station Road, Bellbrook | 90.1 | 21.4 |
The bridges go under sooner but clear faster in the same flood: Toorooka Road Bridge is
under 5.5 hours in, for 28.5 hours, and Bellbrook Bridge 10.5 hours in, for 23.5 hours
(Table 32). The report’s summary of the valley is blunt: Residents are typically
used to being cut off for multiple days.
What the model is built on
A flood model is only as good as the floods it was checked against. This one was tuned to
two: March 2001 and June 2011. The report says Most modelled flood levels were within 0.6m
of the observed values
for 2001 and that for 2011 The modelled and observed levels are
generally within 0.4m.
Its own table of significant floods at Bellbrook and Turners Flat
ends in 2013.
What the study was checked against, and what it does not cover
Checked against
The March 2001 flood (calibration) and the June 2011 flood (validation), using the
water level gauges along the river from Bellbrook down to Aldavilla. The report says the
model matched 2011 better, for which more information throughout the Upper Macleay
was available.
Not in the report
The May 2025 flood. The report’s revision history dates its draft to July 2024
and its final report to March 2025; the exhibition version is June 2026. Its community
consultation section, page 8, gives one sentence of purpose and then: TBC
That is not a flaw the council hides. Its project page lists 2025 - Data
Collection
as a completed stage, though it does not say what was collected, and the
survey it is running asks for exactly what a newer flood would add: residents’
observations of earlier floods, flood levels at particular places, and photographs. The report’s last recommendation is the same point
from the other side: It is recommended that data collection in future events target
Upper Macleay River.
The same 15 September meeting reached the gauges themselves. On a notice of motion from
Cr Bain, amended by Cr Paix, councillors resolved 8 votes to 0 to write to the Federal
Member for Cowper, Pat Conaghan MP, asking for advocacy to prioritise the upgrading of
flood gauges on the Macleay River
under the federal Flood Warning Information Network
program, and to seek federal ministers’ support for flood gauge infrastructure
throughout the Macleay River catchment
(resolution 2026.175).
Where it sits, and how to have a say
Councillors voted 8 to 0 on 15 September to put the study on exhibition and hold the
Willawarrin session, and noted that the final study will come back to them after feedback
(resolution 2026.170). The council paper says the study does not itself amend (and
certainly does not worsen)
the council’s existing floor level requirements. A
flood study is the first of four stages in the state’s process; the risk management
study and plan that follow are where options and controls are weighed.
From model to plan
- Oct 2023Site visit with the council: bridges, culverts, photographs.
- Jul 2024Draft report.
- Mar 2025Final report.
- Jun 2026Public exhibition report.
- 15 Sep 2026Councillors endorse exhibition, 8 votes to 0 (resolution 2026.170).
- Fri 16 OctPresentation and questions with WMAwater and council staff, Willawarrin Community Hall, 22 Armidale Rd, 1pm to 3pm.
- Thu 29 OctSurvey closes 11.59pm. Email ksc@kempsey.nsw.gov.au or post to the Chief Executive Officer, PO Box 3078, West Kempsey NSW 2440.
- No dateFinal study reported back to council. Then the floodplain risk management study and plan.
Our view
This is the document the upper valley has been missing, and its most useful pages are not the flood maps but the plain tables: which bridge, at what level, for how many hours. Those numbers are what a family deciding whether to stock up, or a school bus route, or the SES, actually needs, and the report says the emergency classifications will go to the SES when the project is complete.
Its weakness is time. The final report is dated March 2025, two months before the May 2025 flood, and it rests on two floods from 2001 and 2011. That does not make the numbers wrong; it makes the exhibition matter more than usual. Anyone who marked a level, photographed a crossing or timed how long a road was cut in May 2025 holds something this model has never been checked against, and the survey is the place to put it. The final study should say plainly whether the 2025 flood was used and how the model compared.
How we did this. We read the exhibited Upper Macleay Flood Study report (100 pages, June 2026) end to end, item 10.5 and the notice of motion at item 11.2 of the 15 September 2026 business paper, the draft minutes of that meeting, and the Your Say Macleay project page. The bridge count compares two columns of the report’s Table 30 (deck level and the 20% flood level); the road table re-sorts Table 31 without changing a number. The report’s executive summary gives slightly different levels at Bellbrook Bridge (Table 1) from Table 30; we use Table 30 throughout. The exhibited report was published without its figures and maps, so we describe none of them. The minutes are a draft until the council confirms them.
We will read the report that brings the final study back to council and set out what changed after exhibition, including whether the May 2025 flood was used.