Existing Problem: 23 degree Impact Sprinklers on Top of Boom

High Angle Impact Sprinklers High angle impact sprinklers may have two problems that reduce application efficiency -- the operating pressure is typically in the high range (>80 psi) and the angle of spray throws the water high into the air. With high pressure nozzles many of the water droplets are small leading to wind drift, direct evaporation of droplets into air, and loss of water from droplets during settling. With high throw angles, droplets spend more time in the air and thus have more time for those water losses from droplets.

In their favor many of the high pressure, high angle sprinklers spread the water far enough during throws that instantaneous application over a spot on the soil will be lower than infiltration. All applied water, that does not evaporate or drift, will enter the soil.

BMP's suggested below reduce the throw angle and/or the operating pressure.

Water Conserving Practice: Place LEPA/LESA Nozzles on Drops

"Low-Energy Precision Application" (LEPA) and "Low Energy Spray Application" (LESA) -- sprinkler technology developed in Texas-- are two sprinkler packages that move the emitters or sprinklers close to the ground. Typically with LEPA, a bubbler emitter or sock distributes water in a stream that must temporarily be contained in furrow dikes (soil pushed up in wheel tracks and row middles to form miniature basins to hold the water and prevent runoff) until the water can soak into the soil. With LESA a spray nozzle on the long drop tubes sprays water up and outward in a pattern 5 to 10 feet in diameter. With LESA, conservation tillage or good crop cover may be enough to allow the water to enter the soil. Follow this link for more information:http://www.cprl.ars.usda.gov

Source: Evans, R.O., K.A. Harrison, J.E. Hook, C.V. Privette, W.I. Segars, W.B. Smith, D.L. Thomas, and A.W. Tyson. 1998. Irrigation conservation practices appropriate for the Southeastern United States. D.L. Thomas (ed.) Geologic Survey Project Report No. 32. Georgia Geologic Survey, Georgia Department Of Natural Resources, Environmental Protection Division, Atlanta, GA 30334. 43p.