Bletchley flood map & planning overlays
A planning-constraint profile of Bletchley
(Alexandrina Council, SA) - 23.58 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
23.58 km² - this suburb is highly constrained by planning overlays.
Elevation hillshade with street names, clipped to Bletchley'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 Bletchley
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.
Bletchley at a glance
How Bletchley is zoned
Selling in Bletchley? 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 23.58 km², Bletchley is highly constrained by planning overlays. About 4% of the suburb sits within a mapped flood overlay, and 100% is flagged bushfire-prone. The dominant land-use zone is Rural. The median lot measures about 263,079 m² across 53 parcels.
Who lives in Bletchley
Census 2021 figures published by the ABS for the Bletchley 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 1016, and decile 8 within South Australia. The national average is 1000.
Age profile
Share of Bletchley's 76 residents in each ABS age band.
Population trend, 2001 to 2025
Estimated resident population of Strathalbyn Surrounds, the wider ABS statistical area containing Bletchley. There is no annual population series published at suburb level, so this describes the surrounding area rather than Bletchley itself.
5,223 in 2001 to 8,615 in 2025, up 65%.
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.
Bletchley 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 Bletchley 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.
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 Bletchley lot.
See what's in the $9 report →Bletchley planning - frequently asked
Is Bletchley flood-prone?
About 4% of Bletchley falls within a mapped flood overlay, against the council-wide suburb average of 16%.
Is Bletchley bushfire-prone?
Around 100% of Bletchley is mapped as bushfire-prone, compared with a Alexandrina Council average of 100%.
Is Bletchley under a flight path?
Aircraft were observed over about 22% of Bletchley in the period sampled, but only above 3,000 ft - the lowest measured was 4,000 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 Bletchley?
The dominant planning zone in Bletchley is Rural, though the suburb also includes Rural Horticulture.
Does Bletchley have heritage-listed places?
No heritage-listed places are on record within Bletchley.
What is the typical lot size in Bletchley?
Across 53 surveyed parcels in Bletchley, the median lot size is about 263,079 m².
What is the population of Bletchley?
At the 2021 Census Bletchley had 76 usual residents, with a median age of 41 and an average household size of 3.2 people. The wider Strathalbyn Surrounds statistical area, which contains Bletchley, went from 5,223 people in 2001 to 8,615 in 2025, up 65%.
Is Bletchley an advantaged suburb?
On the ABS SEIFA 2021 index of relative socio-economic advantage and disadvantage (IRSAD), Bletchley scores 1016 and sits in decile 7 of 10 nationally and decile 8 within South Australia (decile 1 is the most disadvantaged tenth, decile 10 the least).
What is the median household income in Bletchley?
Median household income in Bletchley was $1,875 a week at the 2021 Census, against $1,655 for the typical suburb in Alexandrina Council. Median rent was $100 a week and the median mortgage repayment $1,850 a month.
Compare nearby suburbs
| Nearby suburb | Distance | Flood mapped | Bushfire-prone |
|---|---|---|---|
| Belvidere | 4.8 km | 0% | 100% |
| Woodchester | 4.8 km | 0% | 100% |
| Willyaroo | 6.5 km | 0% | 100% |
| Hartley | 7.5 km | 0% | 100% |
| Langhorne Creek | 9.1 km | 29% | 100% |
| Highland Valley | 9.2 km | 0% | 100% |
| Angas Plains | 9.4 km | 29% | 100% |
| Strathalbyn | 10.2 km | 0% | 99% |
| Gemmells | 11.2 km | 0% | 100% |
| Red Creek | 11.2 km | 0% | 100% |