More photos of the construction Part of our Food Web project is building a self-containing water system. We don't have a well, and we are too far from the river to get water from there. So, we run our homestead off rainwater. We have started construction on the Food Web's water. It is a 7,000+ gallon rain catchment system. We've been experimenting with liner-tanks for large capacity water storage, and this one is coming out great. The basic concept with these tanks is to make a support structure to hold a liner (animal safe or potable, depending on your needs). The structure has to be able to hold the liner in place, and resist the pressure of the water, especially at the base. The trick is to avoid making the tank very tall. A 4ft tall tank has only 1.8 psi at the base, no matter how wide the tank is. 1.8 psi is not a lot of pressure, and can be held with a very basic frame, like wire mesh, plywood, or sheet metal. In this version, we used wire mesh. This is how those cheap wal-mart pools are able to hold all of that water, they are not very tall. To build a tank like this, you need to level a site, compact it well, then put down a layer of sand. If you can, make your tank round, and that saves a lot of effort. A round tank just needs a support structure (wire mesh) and a some posts to keep the mesh upright. The posts don't even have to go in the ground. Wire your mesh to the posts, and then a retaining ring at the top and bottom. This ring would be rebar, metal tubing, or anything to hole the thing together. Once you have your structure in place, drop in your liner, and allow at least 6 inches to be folded over the top of the wire mesh. Tie this extra line down, drop in a bulkhead outlet, a bulkhead overflow, and your done! The tank we made cost $1,000, including parts for the roof. If you are using it for irrigation, you don't really need a roof, just throw some minnows and fish in there to keep the bugs down. You can also make a hoop house or dome roof with a tarp and some PVC pipe. Here's some more details about how we built the tank: http://www.velacreations.com/blog/item/280-barn-tank.html
Strong suggestion: Set up the tank with cells, rather than the whole kit and caboodle as a single tank. That way, if one cell gets crapped up with something, you don't lose the entire storage. (Or more than one tank ---)
that's a good idea, and we'll consider that with the next tank. We do have our water supply divided into tanks. We try and add a tank or two each year to increase out water capacity. This tank has brought our capacity up to about 15,000 gallons, all filled with rain.
