[Homestead] Water, water, water, was Ram pump rules of thumb
don.bowen at earthlink.net
Thu Sep 14 13:42:00 EDT 2006
At 9/2/2006, you wrote:
>How much would the tanks cost?
>Where is there a guideline for roof size, annual rainfall in inches and
It has been a while but I am now with a decent connection again so I can
deal with old emails.
One gallon of water is 231 cu. in. One inch of rain on one square foot is
144 cu. in. So every square foot of roof will collect 0.623 gallons of
water for every one inch of rainfall.
Roof area * 0.6233 * annual rain fall = Total gallons available.
The real numbers will be less that the calculated due to evaporation and
other factors but the totals are so high that you have some to spare. A 30
by 30 shop roof will collect 60,000 gallons a year with 45 inches of rainfall.
Tanks are cheaper than I thought. A circular 1300 gallon black or green
poly tank can be had for around $600. A tank that size is about 8 ft in
diameter and weighs around 300# so can easily be transported on a small
trailer and handled by one person.
The more I research it the better I like the idea of a water catchment
system. It would be significantly cheaper than a 200 foot well to install
and the pump would also be significantly cheaper. A used recirculating
pump would be sufficient. Maintenance might be a little more because of
needing to keep leaves out of the gutters. A two tank system would make
it easy to clean.
> >I did some calculations using the Ozarks rainfall of 45 inches a
> >year. These were rough with no allowance for dry years, etc. Using an
> >arbitrary roof size of a 30 by 20 building, I came up with over 60,000
> >gallons a year. I found the monthly averages and used a spread sheet for
> >the monthly water usage. Two 750 gallon tanks would store enough to cover
> >the dry spells.
Don Bowen Awl Knotted Up KI6DIU
My travel journal
I am omnivagant.
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