Nepean Bay flood map & planning overlays
A planning-constraint profile of Nepean Bay
(Kangaroo Island Council, SA) - 44.75 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
44.75 km² - this suburb is highly constrained by planning overlays.
Elevation hillshade with street names, clipped to Nepean Bay'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 Nepean Bay
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 3 Oct 2026
Night movements: not established - night is sampled as often as day, but too few night flights have been seen here to conclude either way.
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.
Nepean Bay at a glance
How Nepean Bay is zoned
Selling in Nepean Bay? The zone and overlays on this page are the Planning and Design Code controls a Form 1 vendor's statement has to disclose.
Across its 44.75 km², Nepean Bay is highly constrained by planning overlays. About 16% of the suburb sits within a mapped flood overlay, and 90% is flagged bushfire-prone. The dominant land-use zone is Rural. The median lot measures about 1,025 m² across 331 parcels.
Who lives in Nepean Bay
Census 2021 figures published by the ABS for the Nepean Bay 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 992, and decile 6 within South Australia. The national average is 1000.
Age profile
Share of Nepean Bay's 140 residents in each ABS age band.
Population trend, 2001 to 2025
Estimated resident population of Kangaroo Island, the wider ABS statistical area containing Nepean Bay. There is no annual population series published at suburb level, so this describes the surrounding area rather than Nepean Bay itself.
4,227 in 2001 to 5,212 in 2025, up 23%.
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.
Nepean Bay 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 | the South Australian Planning and Design Code and Location SA spatial data |
| Bushfire-prone mapping | Mapped | the South Australian Planning and Design Code and Location SA spatial data |
| Zoning | Mapped | the South Australian Planning and Design Code and Location SA spatial data |
| Heritage and environment | Mapped where published | the South Australian Planning and Design Code and Location SA spatial data |
| Aircraft noise contours (ANEF) | Not held | the South Australian Planning and Design Code and Location SA spatial data, 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 Nepean Bay 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 10% of Nepean Bay. 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 Nepean Bay lot.
See what's in the $9 report →Nepean Bay planning - frequently asked
Is Nepean Bay flood-prone?
About 16% of Nepean Bay falls within a mapped flood overlay, against the council-wide suburb average of 7%.
Is Nepean Bay bushfire-prone?
Around 90% of Nepean Bay is mapped as bushfire-prone, compared with a Kangaroo Island Council average of 96%.
Is Nepean Bay under a flight path?
Aircraft were observed below 3,000 ft over about 10% of Nepean Bay, and over about 20% at any altitude up to 10,000 ft, in the period sampled (4 Sep 2026 to 3 Oct 2026). The lowest measured aircraft was at 500 ft, with an average of 3,500 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 Nepean Bay?
The dominant planning zone in Nepean Bay is Rural, though the suburb also includes Conservation and Coastal Waters and Offshore Islands.
Does Nepean Bay have heritage-listed places?
No heritage-listed places are on record within Nepean Bay.
What is the typical lot size in Nepean Bay?
Across 331 surveyed parcels in Nepean Bay, the median lot size is about 1,025 m².
Does Nepean Bay have a train station?
There is no train station inside Nepean Bay itself. The suburb is served by 5 bus stops.
What is the population of Nepean Bay?
At the 2021 Census Nepean Bay had 140 usual residents, with a median age of 51 and an average household size of 2.0 people. The wider Kangaroo Island statistical area, which contains Nepean Bay, went from 4,227 people in 2001 to 5,212 in 2025, up 23%.
Is Nepean Bay an advantaged suburb?
On the ABS SEIFA 2021 index of relative socio-economic advantage and disadvantage (IRSAD), Nepean Bay scores 992 and sits in decile 6 of 10 nationally and decile 6 within South Australia (decile 1 is the most disadvantaged tenth, decile 10 the least).
What is the median household income in Nepean Bay?
Median household income in Nepean Bay was $875 a week at the 2021 Census, against $1,249 for the typical suburb in Kangaroo Island Council. Median rent was $235 a week and the median mortgage repayment $940 a month.
Compare nearby suburbs
| Nearby suburb | Distance | Flood mapped | Bushfire-prone |
|---|---|---|---|
| Ballast Head | 8.9 km | 2% | 99% |
| Haines | 9.3 km | <1% | 100% |
| Muston | 9.5 km | 4% | 96% |
| American River | 9.7 km | 30% | 71% |
| Brownlow Ki | 10.0 km | 48% | 88% |
| Kingscote | 11.2 km | 6% | 92% |
| Sapphiretown | 11.2 km | 60% | 47% |
| Cygnet River | 12.4 km | 28% | 90% |
| Island Beach | 12.7 km | 20% | 85% |
| Pelican Lagoon | 15.9 km | 10% | 94% |