This is a re-write of the water harvesting here at Nowty Towers which was done in 2013, having been lost at st elsewhere. It will just cover the water harvesting aspects rather than the culvert repair shenanigans which enabled it.
Half meter diameter concrete culvert under my house with one of the original house pilings (30 years prior) had been driven through it. It created a sink hole and obviously it had to be fixed, very long story.

6 months of hard labour later it was mainly fixed by creating a large concrete box culvert bypass around the offending pilling.

I bought a 500 litre tank which fitted the hole I had dug for the general working area for the culvert repair. The area would have otherwise needed to have been filled in, so it made sense to use the space for the tank. I just had to find one of a suitable size and shape.

I'll add bits more to this over several days...............