Main Arm flood map & planning overlays
A planning-constraint profile of Main Arm
(Byron, NSW) - 25.72 km², mapped from live council and
state overlay data. This suburb is highly constrained.
Profile updated 3 October 2026.
Suburb-wide figures; the free map shows which overlays touch your lot.
Constraint readout
25.72 km² - this suburb is highly constrained by planning overlays.
Elevation hillshade with street names, clipped to Main Arm's boundary, with the flood, bushfire and environmental overlays drawn on top. Magenta is where aircraft were observed in the sampled period, brightest below 3,000 ft.
Nearby suburbs, nearest first
Aircraft noise and flight paths over Main Arm
Two different things, kept apart on purpose. The ANEF contour is the planning instrument - a forecast published per airport that planning schemes use to control noise-sensitive development. Observed overflight is what a sampled aircraft-tracking feed actually recorded over the suburb - where aircraft flew, how low and how often.
Observed overflight - sampled 4 Sep to 2 Oct 2026
Night movements: observed, lowest 6,000 ft - night is sampled as often as day, but night traffic is light, so this is a floor and no rate can be put on it.
Traffic is sampled rather than watched continuously, so every figure is a floor: aircraft not captured between samples are not represented. Rates are per 500 m square - the busiest square in the suburb, not a count of flights over the suburb - and a square is only rated where enough traffic was seen to measure it. Altitudes are above mean sea level. Flight paths change with runway use, weather, season and airspace design. This is a record of observed traffic; it is not a noise contour and not a planning control.
Main Arm at a glance
How Main Arm is zoned
Buying in Main Arm? The zoning, flood and bushfire lines on the section 10.7 certificate attached to the contract are mapped controls - see our s10.7 certificate guide.
Across its 25.72 km², Main Arm is highly constrained by planning overlays. About 10% of the suburb sits within a mapped flood overlay, and 100% is flagged bushfire-prone. There are 5 heritage-listed sites on record, and the dominant land-use zone is Rural Landscape. The median lot measures about 20,888 m² across 232 parcels.
Who lives in Main Arm
Census 2021 figures published by the ABS for the Main Arm suburb boundary itself, not a wider region.
Socio-economic standing
ABS SEIFA 2021 ranks every Australian suburb. Decile 1 is the most disadvantaged tenth of the country, decile 10 the least.
Score 993, and decile 5 within New South Wales. The national average is 1000.
Age profile
Share of Main Arm's 640 residents in each ABS age band.
Population trend, 2001 to 2025
Estimated resident population of Mullumbimby, the wider ABS statistical area containing Main Arm. There is no annual population series published at suburb level, so this describes the surrounding area rather than Main Arm itself.
7,623 in 2001 to 9,662 in 2025, up 27%.
Source: ABS Census 2021 and SEIFA 2021 (Suburbs and Localities), Regional Population (SA2), CC BY 4.0. Small counts are randomly adjusted by the ABS.
Main Arm data sources and coverage
“Not mapped” means we hold no source layer for this suburb - never an all-clear.
| Dataset | Coverage | Publisher |
|---|---|---|
| Flood mapping | Mapped | NSW Government spatial services, NSW ePlanning and published council flood studies |
| Bushfire-prone mapping | Mapped | NSW Government spatial services, NSW ePlanning and published council flood studies |
| Zoning | Mapped | NSW Government spatial services, NSW ePlanning and published council flood studies |
| Heritage and environment | Mapped where published | NSW Government spatial services, NSW ePlanning and published council flood studies |
| Aircraft noise contours (ANEF) | Not held | NSW Government spatial services, NSW ePlanning and published council flood studies, Defence |
| Observed flight paths | Observed | adsb.lol, under the Open Database License |
| Demographics | Available | Australian Bureau of Statistics (2021 Census and SEIFA) |
Profile last materially updated 3 October 2026. See the methodology and full source list. Source data changes over time and critical decisions should be checked with the responsible authority.
Check a specific Main Arm address
See exactly which overlays touch a single property - the interactive map is free. Need it on paper? A full planning PDF is just $9.
Aircraft have been seen below 3,000 ft over about 12% of Main Arm. The report's Aircraft Overflight page narrows that to the address itself: how many aircraft a day, how low, and at what heights.
Building or pricing a slab? The $119 geotechnical desktop report covers geology, soils, bores and an indicative AS 2870 site class for a Main Arm lot.
See what's in the $9 report →Main Arm planning - frequently asked
Is Main Arm flood-prone?
About 10% of Main Arm falls within a mapped flood overlay, against the council-wide suburb average of 22%.
Is Main Arm bushfire-prone?
Around 100% of Main Arm is mapped as bushfire-prone, compared with a Byron average of 94%.
Is Main Arm under a flight path?
Aircraft were observed below 3,000 ft over about 12% of Main Arm, and over about 44% at any altitude up to 10,000 ft, in the period sampled (4 Sep 2026 to 2 Oct 2026). The lowest measured aircraft was at 2,000 ft, with an average of 4,500 ft. Traffic is sampled rather than watched continuously and flight paths change with runway use, weather and season; the ANEF contour is the planning instrument.
What is the zoning in Main Arm?
The dominant planning zone in Main Arm is Rural Landscape, though the suburb also includes Environmental Conservation and Primary Production.
Does Main Arm have heritage-listed places?
Main Arm has 5 heritage-listed places on record.
What is the typical lot size in Main Arm?
Across 232 surveyed parcels in Main Arm, the median lot size is about 20,888 m². There are also 13 registered easements mapped in the suburb.
What is the population of Main Arm?
At the 2021 Census Main Arm had 640 usual residents, with a median age of 45 and an average household size of 2.8 people. The wider Mullumbimby statistical area, which contains Main Arm, went from 7,623 people in 2001 to 9,662 in 2025, up 27%.
Is Main Arm an advantaged suburb?
On the ABS SEIFA 2021 index of relative socio-economic advantage and disadvantage (IRSAD), Main Arm scores 993 and sits in decile 6 of 10 nationally and decile 5 within New South Wales (decile 1 is the most disadvantaged tenth, decile 10 the least).
What is the median household income in Main Arm?
Median household income in Main Arm was $1,403 a week at the 2021 Census, against $1,634 for the typical suburb in Byron. Median rent was $450 a week and the median mortgage repayment $1,733 a month.
Compare nearby suburbs
| Nearby suburb | Distance | Flood mapped | Bushfire-prone |
|---|---|---|---|
| Palmwoods | 2.4 km | Not mapped | 100% |
| Upper Main Arm | 3.5 km | Not mapped | 100% |
| Koonyum Range | 4.1 km | Not mapped | 100% |
| The Pocket | 4.1 km | 13% | 100% |
| Upper Wilsons Creek | 4.3 km | Not mapped | 100% |
| Middle Pocket | 4.8 km | 8% | 100% |
| Mullumbimby Creek | 5.2 km | 2% | 100% |
| Wilsons Creek | 6.4 km | 1% | 100% |
| Upper Burringbar Tweed |
6.5 km | 1% | 99% |
| Yelgun | 7.3 km | 9% | 100% |