Med Gardener
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Joined: Tue May 17, 2016 10:40 am

Help expanding Rain barrel sys w/ no outlets & limited space

Irrigation layout for posting.png
Hi Everyone,

I apologize if this is not clear and pretty long, but it's my first time on the site, and I do medicine, not engineering)

I am part of a community garden club at my medical school aimed at providing healthy (& usually store-expensive) vegetable options to underserved persons in our community. We recently expanded in the last year from 3 4x8 raised garden beds to 6 4x8 and this year added 4 5x10 raised beds. Last year, we built a gravity-fed, "zero-pressure" drip system for the 6 4x8 beds, which was mostly successful, other than not having enough of a reservoir (1, 77-gal barrel on a 3' platform with an automatic timer fed by a gutter of 150 sqft roof), but with the expansion, we are not sure how to sustain the autonomy of the system. We recently obtained a 330gal rectangular tank for the main reservoir, but have yet to elevate it (space is limited, and we only have the one gutter to tap). In addition to the space and water-source problem, we anticipate having pressure issues (needed to supplement irrigation with manual watering many times in dryer months) again, and are not sure how to fix them, as the roof from which we get the water is only 7', and we cannot reasonably raise the tanks much higher and still have them fill. Yet another issue with the idea of using a pump to supplement the pressure is that we have no access to any power outlets.

My original idea was to attach a 55gal barrel side-by-side with the 77gal (increased capacity at the raised height), then run an overflow pipe from the top of the 77gal into the 330gal tank to capture as much as possible during this rainier time of the year (we are in northeast PA, and last July we did not have enough water to maintain the system), but the issue then arises with how to send the water back up to the raised barrels to supply the beds. I toyed-around with the idea of purchasing a 2m lift solar fountain pump that would continuously pump the water from the large 330gal reservoir into the barrels, and just let the overflow drain back into the reservoir via overflow pipe, since solar power won't be wasting any energy and it would ensure the barrels stayed filled to maintain more pressure. This makes logical sense to me, and is practically simple, but I do not know enough about low pressure irrigation systems to know if this would work out in actuality.

A little basic/general background on the plot:

The 6 4x8 raised beds are closest to the barrel (furthest 2 are about 25-30' away)
The 4 new 5x10 beds are about 10' to the right of the barrel and another 10' in front (see attached picture of the excel layout we made)
I know we need 392sqft x 0.623gal/sqft/wk (including natural rain) to supply them adequately
This is long-winded and probably not too clear, but I have attached a picture of our layout that will hopefully help it make a little sense. My actual question is: how can I rig up a system that will supply all of the beds that is fully or almost completely automated, particularly with the pump, as pressure became an increasingly annoying issue last growing season. Please ask any questions you may have, and try to keep in mind that children will be playing and gardening here, so no open wires or dangerous things. Also, we are future doctors, not engineers, so while we are pretty good at improvising and making things work, we will never be engineers or electricians, so we are trying to devise the simplest system possible that maintains its functionality.

Thank you, and any advice/plans are greatly appreciated!
Irrigation layout for posting.png

Posts: 13906
Joined: Tue Jan 01, 2013 8:32 am
Location: Hawaii, zone 12a 587 ft elev.

If you can lift your barrel as close to the gutter as you can. Run a series of barrels on a raised platform side by side so they are around the same height. Attach the barrels to each other about a couple of inches from the bottom. When you get to the last barrel drill a hole at the top to drain into the reservoir tank that is sitting lower. If that fills you will need an overflow drain from that.

When it rains the water will fill the barrels evenly and empty them evenly. If they fill fast this is not a problem, but
I usually connect the bottom of the first barrel to an overflow port on the top of the next barrel when I have more than two barrels in the system. As the water levels drop in the barrel pressure will drop. Connecting barrels makes each barrel level drop slower. I use short hoses and quick connectors to connect the barrels. That way I can join more barrels together easily if I want to connect three or more filled barrels together. All I have to do is join all of the barrels at the base instead of from the base to the top. I will need to add a two way faucet connector to join hoses from two different barrels, but the last barrel still needs to have the overflow hose. If the pressure gets too low, use a sump pump to pump the water from the reservoir to the barrel to the higher barrels to refill them. shut off the connectors to the partially filled barrels so you can maintain a higher water level in the barrels you are pumping from. The spigot, I use on my rain barrel is acually a shut off valve attached to a 3/4 inch threaded adapter that connects to a Y or a hose. You can get a gas sump pump to transfer the water from barrel to barrel or from a lower reservoir to a higher barrel. Water is heavy so a large reservoir is probably better and safer on the ground since it will need a lot of support for the weight. ... lbZ1z0v5jp ... /100178887 ... r-set.html

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