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AND STORAGE SYSTEM
DESIGN - EQUIPMENT - COSTS - RESOURCES
Source: "Texas Guide to Rainwater Harvesting - Second Edition":
published by the Texas Water Development Board in Austin, Texas, 1997 -
CLICK HERE to read the new 3rd edition of this manual, one of the best available on rainwater harvesting.
Wells in our area of the desert near Tucson, Arizona average nearly 1000 feet deep. This is also "historical" water which will never be replaced. At today's prices, a well would cost in the neighborhood of $25,000 -- far in excess of our budget. Ever since we visited New Zealand almost 20 years ago, we have thought about catching and storing the rain from our roof. There we found New Zealanders, rich or poor, collected the rain from their roofs and stored it in barrels or water tanks. Wells were the exception rather than the rule, municipal water system almost non-existent. Why not do the same thing in our part of the Sonoran Desert where rainfall averages about 12 inches per year?
Initially we used a 2500 gallon polyethylene storage tank to store the rain water from the greenhouse and trailer roofs. Now the roof of the new straw bale house also has collection gutters and pipes and a 15' above-ground swimming pool to add to our storage capacity. This is usually kept covered to keep the water from getting dirty and to avoid evaporation -- which is significant in the dry Arizona climate.
We have a standard pressure tank and a 1/2 horse power jet pump to bring water from the tank(s) and maintain constant water pressure in the house.
Below Mindy is connecting the
pipe from one roof collection point between
our mobile home and the greenhouse to the poly storage tank. This system worked very well
for three years, but the mobile home then had to be removed
because of zoning restrictions.
Now all roof surfaces of the new straw bale house are guttered and piped in to the existing pipes running to the storage tank from the roof of the greenhouse. Pipes running vertically to the ground are "roof washers" -- see the section further on about these..
Note the rain water gushing into our tank from the catchment pipes during a storm. The green material is a synthetic pad for an evaporative cooler (three layers) which we are using to filter out any of the more course particles of dirt or other debris which may have gotten past the roof washers. There is an additional filter for the finer particles located between the storage tank and the jet pump.
We have over 3000 square feet of roof surface to collect rain water between the greenhouse and new straw bale house. TO FIGURE HOW MUCH WATER IS COLLECTED: approximately 600 gallons of rain water is collected for every 1000 square foot of collection area for one inch of rain. Thus one inch of rain produces about 1800 gallons of water and comes close to filling the storage tank. The new above-ground storage pool will hold about 4500 gallons.
(Fortunately our "puppy" doesn't like to swim, but he was
delighted with his new drinking bowl.)
"Roof Washing System"
Roofs get dirty, and the first water caught off the roof is likely to be dirty as well. A simple system to divert this water and discard it (or run it to the garden) rather than letting it go into the storage tank is used. Once the roof washer tube is full (see diagram), water from the roof is free to continue on down the gutter to the storage tank.
Elements of the System
and What We Paid for Them
THE TOTAL WATER HARVESTING SYSTEM
Click HERE for a full page diagram of our water system
and how all elements connect together
RAIN WATER HARVESTING RESOURCES
Comprehensive information on all aspects of water harvesting
(how-to info, types of water storage tanks, videos, sources for equipment,
books, blog, tax breaks in Arizona for water harvesting)
© 2001-2014 by Jim Phypers