Trenah flood map & planning overlays
A planning-constraint profile of Trenah
(Dorset, TAS) - 62.39 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
62.39 km² - this suburb is highly constrained by planning overlays.
Elevation hillshade with street names, clipped to Trenah's boundary, with the flood, bushfire and environmental overlays drawn on top.
Nearby suburbs, nearest first
Aircraft noise and flight paths over Trenah
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 to
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.
Trenah at a glance
How Trenah is zoned
Buying in Trenah? The zone and code overlays on this page are the Tasmanian Planning Scheme controls a section 337 certificate reports for a title.
Across its 62.39 km², Trenah is highly constrained by planning overlays. About 8% 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 399,071 m² across 42 parcels.
Who lives in Trenah
Census 2021 figures published by the ABS for the Trenah 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 943, and decile 6 within Tasmania. The national average is 1000.
Population trend, 2001 to 2025
Estimated resident population of Scottsdale - Bridport, the wider ABS statistical area containing Trenah. There is no annual population series published at suburb level, so this describes the surrounding area rather than Trenah itself.
7,407 in 2001 to 7,076 in 2025, down 4%.
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.
Trenah 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 Tasmanian Planning Scheme and the LIST (Land Tasmania) |
| Bushfire-prone mapping | Mapped | the Tasmanian Planning Scheme and the LIST (Land Tasmania) |
| Zoning | Mapped | the Tasmanian Planning Scheme and the LIST (Land Tasmania) |
| Heritage and environment | Mapped where published | the Tasmanian Planning Scheme and the LIST (Land Tasmania) |
| Aircraft noise contours (ANEF) | Not held | the Tasmanian Planning Scheme and the LIST (Land Tasmania), 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 Trenah 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.
Published flood models are held over parts of Trenah. The free check tells you whether one reaches an address; where it does, a Flood Model Report is +$9 with the planning report.
See what's in the $9 report →Trenah planning - frequently asked
Is Trenah flood-prone?
About 8% of Trenah falls within a mapped flood overlay, against the council-wide suburb average of 11%. Published flood models are held over parts of Trenah; the free check on the Flood Model Report page says whether one reaches a given address.
Is Trenah bushfire-prone?
Around 100% of Trenah is mapped as bushfire-prone, compared with a Dorset average of 99%.
Is Trenah under a flight path?
No aircraft were observed over Trenah in the period sampled (recent weeks to now). Sampling is intermittent, so that is a floor rather than proof that none fly over. 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 Trenah?
The dominant planning zone in Trenah is Rural, though the suburb also includes Environmental Management and Agriculture.
Does Trenah have heritage-listed places?
No heritage-listed places are on record within Trenah.
What is the typical lot size in Trenah?
Across 42 surveyed parcels in Trenah, the median lot size is about 399,071 m².
Is Trenah an advantaged suburb?
On the ABS SEIFA 2021 index of relative socio-economic advantage and disadvantage (IRSAD), Trenah scores 943 and sits in decile 3 of 10 nationally and decile 6 within Tasmania (decile 1 is the most disadvantaged tenth, decile 10 the least).
Compare nearby suburbs
| Nearby suburb | Distance | Flood mapped | Bushfire-prone |
|---|---|---|---|
| Talawa | 5.0 km | 12% | 100% |
| Ringarooma | 8.3 km | 12% | 100% |
| Alberton | 10.3 km | 10% | 100% |
| Legerwood | 12.7 km | 13% | 99% |
| Tayene Launceston |
12.8 km | 5% | 100% |
| Cuckoo | 13.0 km | 6% | 100% |
| Upper Esk Break O'Day |
13.6 km | 5% | 100% |
| South Springfield | 14.4 km | 8% | 100% |
| Tulendeena | 15.1 km | 6% | 100% |
| Upper Blessington Launceston |
15.6 km | 7% | 100% |