I suspect it’s a case of:

– area was subdivided decades ago, before town planing was a thing
– since the, council has decided that the area is not suitable for closer development
– and so the subdivisions have had a restructure overlay applied so that the blocks of land are not built upon unless consolidated with neighbouring properties

One of the other concerns with these small blocks in unsewered is that they’re too small for a septic tank to be installed.

That was a quick response, thank you. Why are they still in place after such a long time, if there’s no plans to implement them? How do you find out when they were introduced?

They’re another example of “old and inappropriate subdivisions” – I’ve written about examples elsewhere here:

https://wongm.com/2020/05/old-and-inappropriate-subdivisions-of-victoria/

For the ones in Moorabool, where is a map for the one in Elaine North – in the middle of nowhere:

https://planning-schemes.app.planning.vic.gov.au/static/maps/C107moor/moor/moorabool50ro.pdf

Wallace, beside the freeway.

https://planning-schemes.app.planning.vic.gov.au/static/maps/C107moor/moor/moorabool11ro.pdf

The township of Rowsley:

https://planning-schemes.app.planning.vic.gov.au/static/maps/C107moor/moor/moorabool45ro.pdf

And in the forest at Blakeville.

https://planning-schemes.app.planning.vic.gov.au/static/maps/C107moor/moor/moorabool14ro.pdf

Another from my part of the world was Hansworth Street next to Waverley Gardens Shopping Centre which opened its first stage in 1977 and second in 1981. A short section of Hansworth Street was missing for the reason that it was originally part of VFL Park but was cut off soon after when Stage 2 of the Mulgrave Freeway was built through

The original site (Map 80 H4) …
http://melwayed1.melway.com.au/080.jpg

Cut off by the freeway construction around 1971
https://digitised-collections.unimelb.edu.au/bitstream/handle/11343/23961/302583_UDS2012032-5-0089-wm.jpg?sequence=89

Freeway with the Hansworth Street dotted in never to be built. As I hear the residents were quite happy not to have shopping centre traffic pass through so it was never completed.
https://digitised-collections.unimelb.edu.au/bitstream/handle/11343/23964/305380_UDS2013221-8-0109-wm.jpg?sequence=109

After decades of remaining vacant the site eventually became an Aged Care facility.

Quite a curious arrangement – and not apparent unless you grew up there, or spend hours playing “spot the difference” in the Melways.

By the sounds of it Sandstone Island is now owned by a syndicate:

http://www.domain.com.au/news/two-western-port-bay-islands-for-sale-20151221-glr4j6/

Benjamin Street in Sunshine is another example of a slow to develop subdivision:

https://www.google.com.au/maps/@-37.7936128,144.8320127,3a,60y,181.58h,82.14t/data=!3m6!1e1!3m4!1sqBBoIVJ9Oe5TbBtmmIBqwA!2e0!7i13312!8i6656

The terrace houses pictured were built in the 1890s, but it took until the 1920s for the rest of the estate to develop, with the last blocks not being filled until the 1950s.

http://www.brimbank.vic.gov.au/files/20062dc9-a5a9-499d-aad1-9f040090b4bf/HO25_-_Railway_Station_Estate.pdf

Nice find there!