Rainwater recovery for the garden and emergency use

Self | 4/6/2011 | Beancounter

[Bean Counter]

Over the past few months I have made several references to my water tank in the gardening threads and in several of the emergency prepper threads. I've decided to put up a thread here at FR with pictures to explain what I did and how, and be able to reference this thread when I need to.

This is not the end-all be-all by any means. This is one man's ideas and my only challenge is to find a way to do what I did, only better.

Pass this on and use any of the pictures or comments in any way that you find beneficial.

Cheers!

[Bean Counter]

The Task: Provide a renewable water source on the South end of the house that will irrigate a new raised vegetable garden, and, provide a ready to use emergency water supply, ready to filter and sterilize.

I have built small rainwater recovery systems before, using food grade plastic 55 gallon barrels. My henhouse has such a system and it provides them with unlimited water that I do not have to haul or pipe out there, or buy from the City. Here's a look at that system:



The coop roof slopes back, and all of the water is caught in a gutter and diverted into the barrel until it is full, then into the downspout. A standard poultry watering dish finished the project. Please not the substantial 4x4 supports required to hold that 400 pound barrel up.

For the new system I needed a lot more than 55 gallons.

I shopped around online and came across "Plastic Mart"...

http://www.plastic-mart.com/class.php?item=3698

That's the page I used to order my tank. In short, they are a Nationwide broker for plastic tanks, and they arrange to ship these tanks anywhere in the Country from the nearest manufacturer. As it turned out I have a manufacturer 10 minutes from my home, so I got a 300 gallon tank wholesale online and picked it up myself.

The only problem with a tank that size is the ultimate weight when filled. Water weighs 8 pounds per gallon, so a 300 gallon tank will hold 2400 pounds of water. In addition, you need to have the tank high enough to create a "head" in order to move the water around without a pump.



The site is between the end of my house and the fence, and is about 7 1/2 feet wide. The plan is to put in a retaining wall down the middle with a paved path to the left and a raised bed to the right. In the foreground is where the tank will eventually go.

I started by shoveling all of the topsoil out of the left half and onto the right half where the bed will be, and laid down a strip of landscape barrier cloth. Then I moved about three yards of gravel in and buried the cloth.

The tank is 43 inches in diameter, so I excavated a 6' square foundation about 8" deep, and backfilled it with gravel up to the level of the filled pathway. I rented a plate compacter and packed all of the gravel down thoroughly. I checked it for level, adjusted it and packed the foundation again.





I used dense pre-formed concrete landscaping stones, and placed 11 of them in a circle over a thin bed of sand, and 10 more on top of those. I used cargo straps to cinch the blocks together and keep them from moving until I could get weight on them.

It's important to note that the center of the blocks has to be filled and solidly. I used rocks and rubble to take up some space, then filled the whole volume with gravel. I packed it with a steel rod and a hand tamper, then added several bags of coarse sand, and tamped it in too, until the whole pad was completely filled. If it does not support the tank, the bottom will fail.



Then it was a matter of installing pavers around the foundation and filling the gaps with sand to ensure the bottom will never move. At this point I was ready to set the tank.

Another important feature to consider is mosquito-proofing the tank. I made a collar to fit the manhole and installed a cut-down plastic bucket in it. Inside the bucket I stretch a couple of inexpensive nylon paint filters and hold them in place with the bucket lid. Then its a simple matter of cutting an appropriate hole in the lid to fit the downspout, and you're there.




That's what it looks like this Spring. I set the tank on a Friday afternoon and got it roughly plumbed enough to hold water, and overnight in a moderate rain the tank caught 175 galloons! By Sunday morning it was full.

I am using 1" black plastic pipe and drip irrigation fittings to irrigate the raised bed. When the tank is filled it overflows into the drip irrigation emitters.

Again, this is not the only way to do something like this but it is certainly cost effective. Home Depot and Lowes both sell a similar 50 gallon plastic "rain barrel" for $100, and you would need 6 of them to match the capacity of this tank. This is simpler and a lot cheaper, not to mention a 100% renewable and sustainable way to provide no only constant irrigation for growing some of our own food, but an important source of emergency drinking water that is ready for filtering and purifying should TSHTF...

[IrishCatholic]

Thanks for the pictures. What is your garden plan? What are you growing this year? How much light does that area get near the tank? How much rain do you get each year?
It seems you do a lot in a small space.

[mountainlion]

You better check your local laws because catching rainwater is illegal in Colorado.

[Bean Counter]

I’m still working on the garden plan, but I do have a lot planned for this space. I’m digging the beds out about 2 feet deep and refilling them with compost and coconut coir to hold the water in the soil. Check in our weekly gardening thread for more details on what’s going in there...

That end of the house gets a lot of sun, and here in the Pacific Northwest we get enough rain year round that I do not think the tank will ever go dry.

[trisham]

Wow! If your screen name wasn’t “Bean Counter” I’d guess you were some kind of engineer. I’m impressed! I could never duplicate what you’ve done, but if you decide to begin a ping list, please add me to it.

[bunster]

Do you need to treat the water in any way to keep it drinkable for humans? Or does the closed system keep it in good condition?

[IrishCatholic]

The water is not potable. The water was collected from run off from the roof and gutter. How much bird poop, squirrel toe jam, air pollution particulate or dust, etc is in the water?
It is fine for garden use, in fact, the lack of chlorine makes it preferable for plants. However, for direct human consumption you need a filter/purification system.
Frankly I like tap water. My local water department here is well run and I have no concerns there.

[MsLady]

I saw something like this done with an old hot water heater.

We have a shallow well and a deep well. The old shallow well hasn't been used in a few years. We are going to have a friend put a hand well pump in the basement sink from the old well. I'll just have to run bleach in the old well, let it sit for 24 hours then hand pump like crazy for a few days. Probably use the first water to go scrub stuff ;)

[MsLady]

Your kidding right?

[mountainlion]

The State owns the water in Colorado.

[Bean Counter]

Thankfully it is still perfectly legal to catch rainwater in Washington. And if they change the law the bastards will have to Grandfather me....

An important point to note is that this tank does NOT contain potable water. Potable water is defined as water that is safe for drinking by human beings.

The tank does contain FRESH water, in that the water does not contain any salt. Desalinization is much different from purification, and there is a great difference between the two and it is important to make that distinction.

However, in an emergency this water is perfectly good for filtering and purification by whatever means you plan on using. There are many different filtering systems out there, and this thread is not about which of those is best. I am just trying to demonstrate one fairly simple way that anyone can simply and economically harvest what God lets fall from the sky for any use you have for it.

[Retired Greyhound]

I think it’s brilliant!

Potable or not, the key is to have water available. Finding water in an emergency is the hard part. Purifying it is the easy part.

[MileHi]

You better check your local laws because catching rainwater is illegal in Colorado

Good! I'll be building one in my yard this summer then.

[thackney]

Nicely done. Thanks for sharing.

[count-your-change]

Great idea! A little space and some stuff from the farm supply store will make a quite useful system.

[Nepeta]

Thanks for posting this with all the pics and details!!!