we should get enough rain every month during the growing season… roughly one inch a week. however, the rain comes in storms, as opposed to a nice steady flow, and we cannot always count on it. for example this month we have been short an inch and these hot dry spells are great for picnics, but bad for some plants. our house is fed by a well pump and a pressure tank that provides acceptable pressure for showers and washing dishes. however it was not enough pressure to drive an irrigation system. we are also not super excited about pulling lots of water out of the water table when there is enough rain that falls upon us.
my dream is to harvest rain water and use a solar pump to raise it up onto a water tank on a tower and use gravity pressure to drive a drip irrigation system. great dream to get to work on, but our crops are thirsty now and i need both time and money to get this dream into reality. plan b was to use a pump to pump from our pond and irrigate the fields by sprinkler, but this posed both eco problems of pulling water from a system we do not understand as well as practical problems of filtration, pump size, power, etc.
the plan we have settled on is to capture as much rain as we can from the barn roof. our neighbor, jay, gave us an old gutter and i pieced together some other pieces along with a 1500 gallon tank from tractor supply that JUST fit in the back of the pickup. i picked up a 1 hp pump and got everything hooked up in an afternoon.
we are still terribly under prepared… to put the needed inch down on a 1/2 acre would require 12,000 gallons of water, but our pump provides nice pressure, and we have been doing pretty well gathering water off the roof. the tank also allows us to pump from the well at off demand times and fill up enough water to soak a few sections. we should be able to continue to expand the water capture system and improve our delivery as the season and the years progress.