Lachlan flood map & planning overlays
A planning-constraint profile of Lachlan
(Derwent Valley, TAS) - 55.25 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
55.25 km² - this suburb is highly constrained by planning overlays.
Elevation hillshade with street names, clipped to Lachlan'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 Lachlan
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.
Lachlan at a glance
How Lachlan is zoned
Buying in Lachlan? The zone and code overlays on this page are the Tasmanian Planning Scheme controls a section 337 certificate reports for a title.
Across its 55.25 km², Lachlan is highly constrained by planning overlays. About 5% of the suburb sits within a mapped flood overlay, and 100% is flagged bushfire-prone. There are 18 heritage-listed sites on record, and the dominant land-use zone is Rural. The median lot measures about 35,278 m² across 548 parcels.
Who lives in Lachlan
Census 2021 figures published by the ABS for the Lachlan 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 939, and decile 5 within Tasmania. The national average is 1000.
Age profile
Share of Lachlan's 953 residents in each ABS age band.
Population trend, 2001 to 2025
Estimated resident population of Derwent Valley, the wider ABS statistical area containing Lachlan. There is no annual population series published at suburb level, so this describes the surrounding area rather than Lachlan itself.
2,973 in 2001 to 3,464 in 2025, up 17%.
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.
Lachlan 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 Lachlan 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.
Published flood models are held here: a Flood Model Report is available for about 420 Lachlan addresses (+$9 with the planning report).
See what's in the $9 report →Lachlan planning - frequently asked
Is Lachlan flood-prone?
About 5% of Lachlan falls within a mapped flood overlay, against the council-wide suburb average of 8%. Modelled flood depth, velocity and flood level are held for about 420 Lachlan addresses, from published flood studies; the free check on the Flood Model Report page says whether a model reaches a given address.
Is Lachlan bushfire-prone?
Around 100% of Lachlan is mapped as bushfire-prone, compared with a Derwent Valley average of 97%.
Is Lachlan under a flight path?
Aircraft were observed over about 3% of Lachlan in the period sampled, but only above 3,000 ft - the lowest measured was 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 Lachlan?
The dominant planning zone in Lachlan is Rural, though the suburb also includes Rural Living and Landscape Conservation.
Does Lachlan have heritage-listed places?
Lachlan has 18 heritage-listed places on record.
What is the typical lot size in Lachlan?
Across 548 surveyed parcels in Lachlan, the median lot size is about 35,278 m².
What is the population of Lachlan?
At the 2021 Census Lachlan had 953 usual residents, with a median age of 44 and an average household size of 2.7 people. The wider Derwent Valley statistical area, which contains Lachlan, went from 2,973 people in 2001 to 3,464 in 2025, up 17%.
Is Lachlan an advantaged suburb?
On the ABS SEIFA 2021 index of relative socio-economic advantage and disadvantage (IRSAD), Lachlan scores 939 and sits in decile 3 of 10 nationally and decile 5 within Tasmania (decile 1 is the most disadvantaged tenth, decile 10 the least).
What is the median household income in Lachlan?
Median household income in Lachlan was $1,759 a week at the 2021 Census, against $1,375 for the typical suburb in Derwent Valley. Median rent was $365 a week and the median mortgage repayment $1,300 a month.
Compare nearby suburbs
| Nearby suburb | Distance | Flood mapped | Bushfire-prone |
|---|---|---|---|
| Glenfern | 3.9 km | 4% | 100% |
| New Norfolk | 7.4 km | 15% | 73% |
| Lawitta | 9.3 km | 10% | 96% |
| Malbina | 9.6 km | 12% | 100% |
| Molesworth | 10.3 km | 5% | 100% |
| Crabtree Huon Valley |
10.6 km | 6% | 100% |
| Sorell Creek | 10.8 km | 16% | 92% |
| Mount Lloyd | 11.0 km | 3% | 100% |
| Boyer | 11.1 km | 9% | 91% |
| Collinsvale Glenorchy |
11.3 km | 4% | 100% |