|Big gun on left, pumping tractor at center, positioning tractor at right. click on image for bigger version|
It takes about 4 hours of operation to get water 3" deep into the soil, so each 2/3rd acre is getting about 4*60*100 or 24,000 gallons of water applied.
When people talk about irrigation they often talk about acre-feet. that is, enough water to cover an acre of ground in 12 inches of water. An acre foot of water is about 325,000 gallons.
So I'm applying about 11% of an acre foot with a four-hour application, which works out to be a little over an inch of water over the entire area. For the areas that need water, I'll consume about 3.6 acre-feet of water over the course of this watering; a little over a million gallons.
I'm drawing the water from my manure lagoon; so this is reclaimed water with manure and other stuff in it. So watering and fertilizing at the same time. I've got 14 acre feet of water in the lagoon, which means that I can do this sort of watering 3 times this year.
My intention is the draw all of the water out of the manure lagoon this year so I can do some maintenance on the bottom of it. The previous owner of this farm dumped straight cow manure into the lagoon and those solids have reduced the total holding capacity of the sytem, so later this year I'll rent a long-reach trackhoe and scoop out all of the solids in preparation for the fall and winter rains.