On the Level

We've had an unusually wet winter, which has been good because we turned off the irrigation system in October and we haven't needed it since then, allowing us to procrastinate even more on the next step in the massive irrigation project. But summer is coming soon and it is getting to be time to tie in our wonderful new water tank.

One reason for the procrastination on my part was that I mislaid my calculations for the size of pump we needed. If you buy too large a pump it will run very inefficiently, and you will waste energy. But while I was procrastinating on the Accordion Room, I went through a pile of papers and found the calculations, so there you have it.

We needed a pump that would do about 1/4 HP and 9.1 gpm (gallons per minute), which is a bit small as pumps go. So what I bought last week was a little pump that is 1/2 HP and 12 gpm. Slightly oversized but not ridiculously so.

Our little pump

This pump is not weatherproof, so I have to make it a little pumphouse to live in. But before I do that, I have a couple of tasks, and number one is to install the tank on a level piece of ground.

Here's the tank as we dropped it in December. It's very heavy (maybe 80 lbs.), and with the lid closed the wind can't get in and lift it, so it doesn't want to go anywhere. But the orientation was wrong, and the location was also a bit off. The tank has two holes in it right below the manway (the lid on top that will let somebody climb in to clean the tank or do whatever it is a person might need to do in a water tank), and those need to face the manifold to the left. Also, I wanted it roughly centered on the location of the future deck, so it had to move towards me.

Water tank in situ

I wrestled the tank to the location I wanted, marked the ground with a shovel, then wrestled the tank out of the way. As you can see here, the new location is about 18 inches from the old location, so not a huge change. The thing is, the ground is pretty sloped right about there, and the tank is tall enough that it would end up sticking into the location of the future deck, so I was going to have to dig it down slightly into the ground -- I figure dropping the tank down about six inches would work about right. I dug all the way around the location, but this was going to call for a mass removal of soil.

Perimeter trench

So: pretty straightforward: remove the sod (most of which had been killed by three months under a water tank, anyway), then get the whole thing to a roughly uniform depth from which I can find level.

Rough soil removal complete

Then I just cleaned up the edges and removed soil to make a first go at a level surface. I think I've got the hole down to a decent rough level now, and all it needs is for me to come through and rake it flat, then even the overall level, check with a long carpenter's level so make sure it's not slightly sloped, and tamp it down and recheck the level.

Clean edges, not level

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posted by ayse on 02/25/08