“We use a lot of Close Spacing in this area -- probably 99% of everything that I sell with sprinklers is Close Spacing.”
In Arizona and Imperial Valley, California summer weather brings temperatures of 118-120 °F, and ET rates range between six-tenths to seven-tenths of an inch a day. This means a farmer with 320 acres of land will need at minimum 12 gallons of water a minute per acre just to offset the ET rates in June, July, and August. Farmers in the region are irrigating around 6000 hours a year and farming 12 months out of the year, so most are looking for ways to lower their pumping costs.
Arizona has flat, laser-leveled fields with heavy soil ranging between a sandy loam and clay consistency. Because of the of the heavy soil in the state, farmers also need to keep their wheel tracks dry. Otherwise their machines are prone to getting stuck.
Southwest Irrigation has been recommending LEPA Close Spacing packages for 25 years - and as of 2017 - almost 99% of their sales can be attributed to LEPA technology. The bulk of their packages are spaced at 30 to 40 inches between sprinklers 2 to 3 ft off the ground.
They depend on this technology to keep grower's pumping costs down and wheel tracks dry.
In their experience, a LEPA sprinkler closer to the ground uses less horsepower and less pressure to achieve the same results as a traditional sprinkler that's 3, 4, or 6 feet off the ground. Meaning LEPA Close Spacing lets growers irrigate more acres and save money because they can put more water on the ground more efficiently and get a better uniform crop with it.
"That was kind of a whole idea behind it: water application, energy savings. Take a guy that's pumping 1,000 gallons a minute on his pivot over 120 acres and he's got sprinklers that are ten feet apart and four or five feet off the ground. If you change that over to Close Spacing and lower that sprinkler down to the ground, you're putting more water on the ground. 30-inch spacing will come out traditionally between 98 and 99% uniformity and distribution of water applied. You can't get that with the sprinkler that's ten feet apart and five feet off the ground." - Rick Grimes