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Low Energy Precision Application (LEPA) Irrigation Technology Demonstration Project Participant Request

BPA, in conjunction with Washington State University (WSU) and University of Idaho (UI), is seeking agricultural producers to participate in a demonstration pilot to assess the viability and suitability of the Low Energy Precision Application (LEPA) irrigation technology for broader deployment in the Northwest. Project leads are seeking at least three locations throughout the Northwest.

LEPA technology was originally designed for center pivot irrigation in areas with short water supply and high energy costs. LEPA improves application efficiency, reduces direct evaporation from the sprinkler, and requires less pressure to operate, thus reducing the pump power consumption. Although the technology is primarily used on pivots, it can also be used with lateral move irrigation systems. A LEPA system will save water, save energy, reduce fertilizer requirements, and has the potential to improve crop yield; a win-win for everyone involved.

 Project Introduction
  • LEPA applies water more efficiently to crops, reducing overall water use and associated energy for pumping. This project is looking for all types of crops.
  • Volunteers will be screened based on the suitability of their land's soil and topography.
  • There is no direct cost for participation. Indirect costs may include changes to cultivation practices; opening demonstration sites to other producers; reporting yield information to researchers; and harvesting LEPA crops separately from other crops.
  • The producers may keep the equipment that is installed on their farm after the project.
  • A potential downside to LEPA is runoff and erosion. To reduce the risk of runoff and erosion, LEPA may require certain cultivation practices (see Participant Requirements). Agricultural customers who already practice conservation tillage won't have to drastically change cultivation practices.
  • At the end of the pilot if the producer chooses to upgrade entirely to a LEPA system, benefits include lower energy and water use; potential for less fertilizer use and higher yield.
  • At the end of the pilot if the producer chooses to upgrade entirely to a LEPA system, electricity savings will range from 15 to 30 percent, depending on the distance and elevation water is pumped. Across the board, water savings will be about 15 percent.
 Participant Requirements

LEPA is not universally applicable to all topography, soil types and irrigation practices. A LEPA Test Stand is available to assess the applicability of LEPA on fields.

Because a relatively large amount of water is applied to a relatively small surface area in a short amount of time, LEPA 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 will be most applicable on older fields previously leveled for flood irrigation or sandy soils.

In the demonstration project, only one span of an existing pivot will be converted to LEPA (Figure 2) to enable comparison of LEPA and conventional Mid-Elevation Spray Application (MESA) on water efficiency, soil moisture (Figure 3), yield and visual comparisons.

 Education and Outreach

A "field day" may be organized and held at each location in the middle of each irrigation season. During this field day, equipment dealers, agricultural consultants, and individual growers will listen to a short demonstration of the system, be able to see the system in operation and get a chance to ask questions of the experts and the grower-cooperator.

figure 1
Figure 1. LEPA on a center pivot using drag-socks
Figure 2
Figure 2. Pivot plot plan
Figure 3
Figure 3. Demonstration of soil moisture and datalogger locations.


For more information: Please contact your Energy Efficiency Representative or Dick Stroh, BPA Agricultural Engineer, at (208) 612-3154.

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