Photo credit: Southern California Edison, Pump Testing and Hydraulic Services
Step 3
Have a pump efficiency test performed by a professional tester.
The pump tester basically measures three things: flow rate (gallons per minute), pressure (including the lift from the water source and discharge pressure to the irrigation piping), and energy in from the power source (kilowatts on electric metered pumps; fuel burn rate with diesel, gasoline and propane; or therms with natural gas pumps). The test will give the grower not only water horsepower being produced in flow and total lift of the pump, but it will also give an overall pump efficiency measuring the energy horsepower in versus the water horsepower out of the pumping plant. This will tell the grower how efficiently the water is moving to the irrigation system. This doesn’t replace the need to install flow meters and pressure gauges. It’s only a snapshot of the test done that day, not what is happening a few months or years from the test date.
If any of these indicators show poor pump performance, work with a reputable pump company to correct the problem so that you achieve proper flow and pressure delivered to the irrigation system.
Bill Green is an education manager at the Center for Irrigation Technology at California State University, Fresno, while also farming and managing his family’s raisin grape vineyard near Fresno.
Beyond the pump
Irrigation system maintenance extends to other areas of a pressurized irrigation system.
Check filtration Proper filtration of the water is crucial to ensure clean delivery to the emitters. Make sure your filters are clean and the media is in good shape.
Test water quality
Get the water quality checked by a reputable company to determine what is needed in your field. Water quality varies greatly in different areas. I inject various acids and cleaning materials through the drip a couple of times per year and also continuously apply phosphonic acid to drop the pH to a neutral 7, which keeps the calcium bicarbonate in solution and doesn’t plug emitters.
Flush the mains, submains & drip lines
Every year, flush the ends of the hose out and open the submain valves for a high pressure flush of the lines. One major mistake many growers make is opening too many drip lines simultaneously; instead, open and flush very few lines at a time to maintain pressure and let it run for several minutes to allow all the contaminants in the hose flush.
Monitor distribution uniformity
Regularly determining distribution uniformity can shed light on other issues affecting performance. On my farm, monitoring the flow meter determined a reduced flow rate due mainly to a dropping water table and when I conducted a DU test, uniformity had decreased. I was able to counteract this issue by increasing the horsepower, which brought my flow rate back up.
i Want more information?
The Center for Irrigation Technology located in Fresno, California, takes pump efficiency on the road with its mobile education center pump demonstration trailer. For more information, visit
pumpefficiency.org.
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