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If you want to know what I'm on about in the shortest time then please read the introductory first post and my current action plan. Comments are very welcome. And if you like this blog, please tell a friend. Thanks!

Saturday, 3 November 2007

Maths Problem


A man has two identical water tanks of diameter 2.2m. Mere moments after connecting the downpipes to catch rainwater, the heavens open up and the tanks fill to a height of 0.8m. If the tanks have a combined capacity of 10,000 litres, how much higher can the water rise before it starts to overflow out the side of the tanks where no drain pipe currently exists, quite likely causing serious damage to the compacted rock dust foundation on which the tanks are sitting?


Not bloody far enough! The bottom of the overflow outlet is less than 1.2m higher than the base of the tank, meaning the tanks are about two thirds full after just one night's worth of moderate rain and a couple of showers.

A bit of quick pipe work by my helpful neighbour (the one who installed the downpipes without the drainage in place, saying it wasn't going to rain soon enough to be a concern...) has now mitigated the threat. Any overflow will now be channelled a few metres away over the lawn where it can't cause any major trouble. Proper drainage to the street is a project for another day.

The next question is what to do with around 6,500 litres of water, given that I don't yet have a pump or any plumbing to take water into the laundry and toilet where it's needed. Thankfully the answer doesn't require a calculator: time to go pump shopping.

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