Rainwater Harvesting Complete

 

Author:  Don

This is the completed version of the Rainwater Harvesting project, from catchment to drip emitters.  The first part of the post is not new to some of you, but the second part includes the pump installation, pvc lines, and emitters.  To view a larger version of a picture, just click on the picture.

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Two 2500 gallon tanks fit perfectly on a 16 foot trailer with low sides. I used four 25 foot, 2” racket straps. Highway driving requires additional support (tail gate, board, smaller strap) to keep tanks from sliding back. The tanks weigh approximately 300 pounds each, but can be slid along the dry grass by putting your shoulder into it and bumping them or using a couple of 2×4 boards like train tracks to slide them on.

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Locate your water source, slide the tank into place to make sure the height of gutter to tank has enough of a drop, then the surface needs to be leveled. 1-gallon of water weights a little more than 8 pounds, so make sure the full tank remains level and doesn’t go anywhere. A cement slab is best, but if you have sandy loam soil like I do, just put sand on top to level the surface.

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I have seen several formulas but this one seems to calculate closer to the middle of the various formula totals I have tried: “square footage of roof area   X .6   =  gallons per 1 inch of rain.”   This roof is 23’x60’or 1380 square feet area of collection. One inch of rain should = 828 gallons.

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I extended the roof on the shop for the second tank. This roof is 20’x35’ or 700 square feet.

The rain gutter to water tank plumbing is constructed with 3 inch, 40 schedule PVC pipe.  The pipe going down the side of the tank is a “First Flush” pipe with clean out.  The first flush needs to be cleaned after each rain event.

To finish this project I need to lay pipes underground to connect both tanks, install a pump and continue the underground pipes to locations around the house for gardens, landscape and trough for the cows. Also, I need to plumb the over flow outlet to the ground and away from the tank.

 

 

 

 

 

 

 

 

Additional connections
Additional connections

 

 

 

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Pump Assembly with a homemade housing, framed with treated lumber
On Off Switch with Auto Cutoff @ 20PSI
Exterior Wall painted ¼” Plywood and Insulation
Pipe Support

 

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The pump size is determined by the length of pipe to emitters and PSI required.  The tee connection for the “Clean out line” is optional.

 

 

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The Pump housing is sitting on 12”x12”x1” cement blocks.
I connected the two Tanks with 1 ½ “PVC into the pump.  I’m currently using one tank. The PVC output is ¾” to the Hose Bib.

 

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Connect a pressure regulator to your line depending on drip or spray emitters. PVC runs the length of the Garden centered, with Tee connections spaced accordingly, left and right.  All vendors make threaded adaptors for PVC to the ½” black pipe. I usually flush the line to clear debris before connecting the ¼” line.

 

 

 

 

 

 

Various Sprayers from 360 to 90 degrees

 

 

 

¼” Soaker Hose
Drip with 1 GPM emitter
Adjustable Drip

 

2 Comments

  1. Charles says:

    Thanks for the great guide with photos! You mentioned that with sandy loam soil it’s okay to just level it out with sand and not worry about a cement slab. Does this apply to clay soil as well? What situation would require cement? I’m also curious about the first flush setup you’re using. Does it work on the idea that the flush catch tube fills up and then water can flow on into the tank? Is there anything to prevent floating stuff from going into the tank? Thanks!

    1. Don Smith says:

      Charles,
      I’m glad the picture guide helped.
      I can only speak for myself, but if I had clay soil and a 1000 Gallon tank, I would pour a 3-4″ slab. Cement is expensive and it’s hard to get -via- a cement truck in a small amount unless you rent a small mixer and do it yourself. Most red or black Clay is hard to move around and level, then too much water and it expands, too little water and it may crack. If I installed a 2500 gallon tank or larger on clay soil, the best choice is a slab or I would purchase sand and create a 2-3 inch layer over the clay to cover the size of the tank plus an additional 1 foot barrier to help keep the clay soil moist.
      The first flush is my own personal design, which helps catch the initial debris from the gutter… and yes, when this side tube fills the remaining rain water will go into the tank after going through a screen covering the hole where the water enters the tank. You just need to remember to empty the tube before it rains again.
      Regards-
      Don

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