LEPA and LESA Irrigation Technology

BPA funded research with Washington State University (WSU) and University of Idaho (U of I), partnered in a demonstration pilot to assess the viability and suitability of the Low Energy Precision Agriculture (LEPA) and Low Elevation Sprinkler Application (LESA) irrigation technology for broader deployment in the Northwest. LEPA and LESA technology was originally designed for center pivot irrigation in areas with short water supply and high energy costs. These measures are very popular in the Midwest and Texas.  In the Pacific Northwest, the typical center pivot has sprinklers on top of the top pipe or on drop tubes (which are called Mid Elevation Sprinkler Application (MESA). WSU and U of I focused their research on LESA.

LEPA places the emitter type sprinkler on or just above the soil surface. LESA has the sprinklers located three feet or less above the soil surface and uses spray type sprinklers. LEPA and LESA both double the number of sprinklers on a center pivot. 

Both technologies improve the sprinkler system application efficiency, reduce the direct evaporation from the sprinkler, reduces moisture loss from wet leaves, and require less pressure to operate; thus reducing the pump power consumption per acre foot delivered. Although the technology is primarily used on pivots, it can also be used with lateral move irrigation systems. WSU and U of I found water savings of five to 15 percent. WSU and U of I found that LESAs system may also reduce fertilizer requirements, and has the potential to improve crop quality and yield. It’s a win-win for everyone involved.

Project Challenges

LEPA and LESA are not universally applicable to all topography, soil types, crop planting, and irrigation practices.
Because a relatively large amount of water is applied to a relatively small surface area in a short amount of time, LEPA and LESA has some potential for runoff losses, especially on clay soils and/or sloping ground. To reduce the runoff risk, the use of furrow dikes and/or residue management to hold water in place until it can infiltrate into the soil. It is expected that LEPA and LESA would be most applicable on older fields previously leveled for flood irrigation or sandy soils. Consult with the National Resources Conservation Service (NRCS) or the irrigation sprinkler equipment vendor to determine applicability.