Center Pivot Calibration for Wastewater: A Field Reference Guide

UGA Extension contacts:
Gary Hawkins, Stephanie Hollifield, and Wesley Porter

This publication is intended to be used by those familiar with calibrating a center pivot system. The circular lists the steps, calculations, and charts needed to calibrate a center pivot irrigation system pumping wastewater, without explanations of the process itself. The PDF version contains worksheets and formulas.

The step-by-step calibration procedure includes determining: the wetted diameter of your nozzle or sprinkler; spacing between collection cups; the number of cups needed to collect wastewater from all sprinklers/nozzles. Next, place collection cups in a row, equally spaced in the direction of travel, mark the starting point and then operate the pivot normally and mark the end point. Measure the time taken for the system to pass over all cups. Measure between the start and end points to determine the travel distance. Immediately record the volumes or depths of water in each collection cup and use this to calculate the average application depth (in inches, centimeters, or millimeters). Next, determine your “usable” cups and effective diameter of pivot, and then recalculate the average application depth for the “usable” collection cups. Calculate the reference travel speed and the deviation depth for each “usable” collection cup. Next, determine the average deviation depth, calculate the application uniformity and determine the calibration results.

Published by University of Georgia Cooperative Extension. For more information or guidance, contact your local Extension office.

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