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How much landscape can be irrigated by a pump running  X  hours per week?
   

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Initial numbers in the blanks are provided as examples.  Replace with values you measure.
1. How many hours are you permitted to irrigate per week?
(Current water use restrictions:  http://www.sfwmd.gov/curre/watshort/index2.html )
"We are permitted to irrigate hours per week."
2. How many inches of irrigation per week are needed by the turf?
(Sample water use values:  http://floridaturf.com/staugust/water.htm )
"The turfgrass needs inches per week."
3. What is the total dynamic head (pressure at the pump and lift)?
(Check the head pressure on a gauge immediately downstream from the pump.  The "lift" is the vertical distance between the water table in the well and the sprinkler head.)
"The pump pressure is pounds per square feet and the lift is feet ."
4. What is the pump horsepower and efficiency?
(The pump horsepower will usually be found on a metal plate attached to the motor.)
"The pump is rated at horsepower and the efficiency is %."
5.   "The irrigated area may not exceed acres or square feet based on gallons per minute and total head feet ."

Explanation:  Items 1 and 2 are basically provided to you, so if you know 3 and 4 you can easily find the maximum possible irrigated area.  The total lift and the efficiency are of minor concern.  The lift is relatively unimportant in Florida, because most irrigation is relatively close to the surface, therefore close to the elevation of discharge of the sprinklers.  The efficiency of pumps can vary between 55% and 80%, but this variation is small compared with the other factors, pump size, pressure, hours, and water needs.

Caution:  Things this procedure does not account for are:  rain, roots mining the ground water, and distribution efficiency.  If your sprinklers deliver too much water in some areas, and not enough in others, your total effective irrigated area will be smaller.  Likewise, if some small irrigation zones demand pumping time, even though the pump is not operating to maximum capacity, a smaller irrigated area will result.
   
 
 
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