rainwater collection

[mikim]

I want to collect water off the roof of my metal barn ...and in looking for poly tanks I'm finding the above ground tanks are 1/2 the price of below ground. The above ground ones I've looked at are heavy duty ....thick ...so can somebody tell me why does a buried tank have to have ribs and why can't these above ground tanks be buried? I'm obviously no engineer...but for 1/2 the money - I'm wondering about taking a chance....maybe just bury it 1/2 deep....(I need the clearance for the rain water piping)

[Ridgewalker]

I'm no engineer nor do I play one on TV but my guess is that the ribs are there to provide strength to keep the earth from collapsing your container over time. Pressure will come from the sides as well as the top if buried.

[barrybro]

Keep us posted - I have two barns and I am interested in doing the same thing.

Barry

[randy41]

what size tank do you have in mind?

[SPIKER]

as mentioned the earth will squish the un-ribbed tanks flat, over time, (if it stays 100% full it will take longer to squish it but result will be similar.) if you are in a sandy soil it will squish faster and if clay longer depending on how you place & compact the soil and when back filling tank would need to be FULL and slightly pressurized to kep earth in place.
one other option is to dig a CLOSE fitting hole lower tank into hole center up and fill with water, then pour concrete in smaller lifts to provide support for the tanks. I did this for some small catch basins I made out of 55 gallon drums. used a 3pt crete mixer and made smaller batches and didn't vibrate the crete in as that could make it FLOAT out. same as if the tank is 1/2 full and ground water rises it could cause the tank to FLOAT up and or crush in the sides...

Mark M

[Iron Horse]

When i built my pole home i did not want the Poly tank to spoil the look of the house , so i burried it under the lounge room . After 2 years i decided to clean it out while the water level was low . Even being protected by the house , the soil has started to crush the tank walls in . They are the same profile as corrogated iron and still have bulges in the sides . Another reason why tanks that can be burried have large ribs is apart from being stronger is so that they can grab the earth and help stop them from being floated out when the loose soil around them get saturated with rain . I have had to lift out 6 ton septic tanks for local plumbers and re excavate the holes with my excavator because rain water has floated the tanks and smashed all the fittings because they did'nt fill them with water before going home . So what happens is that after a dry spell you have used most of the water in the tank and if you get a heavy downpour it can float out before it has a chance to fill .

[RalphVa]

I've 2 of the 330 gallon plain plastic tanks; been there about 6 years. Mine are fitted into trenches at the corner of the house and off the corner of the carriage house. They're just slid into the trenches. Terrain around here makes it easy to half bury such things and to provide walk out basements. The one off the right corner of the house is hidden by a boxwood and a tree. The one off the left rear corner of the carriage house is between the extended wall of the carriage house to retain the earth and the other side of the trench beside the retaining wall, with a small retainer on the other side of the trench past the tank. I've a wooden deck above it that I can raise on a couple of hinges and also helps to hide it.

I added 2 more barrels at 75 gallons each this spring. In total, I've 810 gallons now. The 1/2 inch of rain last night filled them all. I'd run out and had pumped out of the little stream down below with my 12v pump a couple of times. That worked well, too.

Ralph

[randy41]

do you use this for irrigation Ralph?
I would like to figure out how much water is discharged in t-tape per hour.

[mikim]

sounds like I'll be putting out some big bucks... I want this to last 20 years. What I have in my head is 2 - 5000 gallon tanks piped together for a 10,000 gallon total available storage. With conservation that could be 3 - 4 months worth of house water. It would negate watering any garden or such ... but the idea is for this to be a backup system in case my well fails and a supplemental system in the meantime. A 5,000 gallon above ground tank is 12' dia and 8' tall which only gives me 1' of fall from the gutters. With the catch & filter stuff prior to the tank ... 1' isn't enough. I"m guessing I'll need about 3' at least. If I could set that above ground tank in the dirt by 3-4' ... it would certainly help. Maybe I can take that suggestion of using some crete to shore up the sides. If I set a concrete pad under the tank, left a small crack around the edge for drainage, then built a 3' concrete retaining wall sorta thing and set the tank in that..... Kinda build a concrete bowl with holes in it for drainage and put the tank in the bowl? would that work? Below ground tanks would be preferred for both clearance, looks, space, and it would keep the water cooler in the summer heat, but they cost! Even with the above ground tanks I'm budgeting $10k for this system.

[RalphVa]

Randy,

My tanks are connected to about 1100-1200' of poly pipe laid through the woods. It runs down to distributors for soaker hoses on each row of the veggie garden and to old hoses to water fruit trees/shrubs. The old hoses to the trees/shrubs just have a 1/8" hole drilled in the hose at the location of each tree/shrub. I've turn-off valves to each row of 3 trees/shrubs.

In the veggie garden, there are turn-off valves to each soaker hose, too. About half of the soakers do 2 rows each. These hoses get plugged up. Every year, I poke new holes where I put seed, with an ice pick.

On each tank, there's a mechanical timer. I'll twirl it on for about 90 minutes of watering. In the past, I was forgetting to turn off the water and would run the tank dry. Each 90 minutes uses about 100 gallons through the soakers. Seems to use a little bit more to a couple lines supplying 6 trees/shrubs.

My little 12v pump does a really good job of supplying water, left on for about 3 hours. It was bought at TSC a few years ago. Pumps 1 to 5 gpm, depending on head. It'll even pump uphill the 100' to my rain tanks, but it's down to about 1 gpm to buck that 43 psi head. After 3 hours, I switch that battery to the one on my electric fence to allow it to recharge off the solar panel. It still has enough juice to run the electric fence.

Ralph