Rainwater Harvesting Part 1

Rosemary threatening to consume rainbarrel

This weekend we’re beginning the process of setting up our rainwater harvesting system.  We’re upgrading from our two little 50 gallon decorative barrels to four 320 gallon IBC totes.

Corgi approved

The city gives a rebate for water saving measures like installing rain barrels and low water landscapes.  When I bought the house, I immediately ran out and bought a couple of little rain barrels, stuck them under the downspouts and waited for the next rain.  It’s Albuquerque so we had to wait a little while. But when it finally did rain both barrels overflowed.  Which was cool but didn’t really help catch all that precious, free water.

How much water can you really catch in the desert?

Brad Lancaster, the Water Guru at Tuscon’s Desert Harvesters , shared this formula for rain harvesting yields in his book Rainwater Harvesting for Drylands and Beyond :

Ft2 of roof x inches of rain x 0.62

Average precipitation in Albuquerque is about 9 inches per year.  Our roof is about 1000 square feet, so we can collect 5580 gallons a year.  It’s definitely not enough to meet our household needs but is enough to manage the garden.  Tucson gets about 15 inches of rain per year, so Brad Lancaster gets about 9300.

We live in a smallish house in the high desert.  A bigger house in a place with more precipitation will collect even more FREE water!  When we were living in MA, it was a dry year and there was not a rain barrel or cistern to be seen.  Can you imagine how much rainwater could be collected in damper climates?

IBC totes are BPA-free plastic cubes wrapped in a metal cage.  We found ours on Craigslist and had them delivered.  Always check to be sure the totes that you buy were used for food. Ours held enzymes.  Companies that used these for storage used to give them away but now they are starting to recognize a potential market and it’s harder find freebies.

Installing these babies is going to be a little more complex to set them up than just sticking barrels under the downspout.  Fortunately we’re still a few weeks out from the start of our monsoon season which is when we get the majority of our precipitation for the year.  We’ve got plenty of time to get it all set up.19620539_10211898743416714_8212150166863831068_o

This weekend we’ll start with the gutters. Our current gutters are vinyl and have not held up to the strong UV radiation that we get at this altitude.  They were installed about 3 years ago and are already sagging.  They’re also angled in the wrong direction.IMG_0877

Frank, who is an engineer by training, has been watching youtube videos for months on the best ways to set up our collection system.  While it’s frustratingly slow for me (the name of this blog was almost going to be “The Impatient Gardener”), everything he does is well-conceived and meticulous.

For more details on harvesting rainwater for your home, check out Brad Lancaster’s book.  This is a link to my Amazon Affiliates account and I will receive a commission if you decide to purchase it.

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