Analysis of Residential Irrigation Distribution Uniformity

Abstract

Irrigation has become commonplace for residential homeowners desiring high quality landscapes in Florida. The goal of this project was to document irrigation system uniformity in Central Florida and to quantify distribution uniformity of residential sprinkler equipment under controlled conditions. The catch-can testing procedure used was a modified version of both the American Society of Agricultural Engineers standard and Florida Mobile Irrigation Laboratory (MIL) procedures. The modified version included a larger sample size to ensure complete sample collection over the entire irrigated area. The standard MIL procedure may overestimate the uniformity for residential systems. From the tests on residential irrigation systems, the average low quarter distribution uniformity (DUlq) value was calculated as 0.45. Rotary sprinklers resulted in significantly higher DUlq compared to fixed pattern spray heads with 0.49 compared to 0.41, respectively. From uniformity tests performed on rotor and spray heads under ideal conditions, rotor heads had more uniform distributions than the spray heads of 0.55 compared to 0.49, respectively. Spray heads had better uniformity when fixed quarter circle nozzles were used as opposed to adjustable nozzles. Both residential irrigation system and controlled tests resulted in (DUlq) at the low end of industry guidelines. Residential irrigation system uniformity can be improved by minimizing the occurrence of low pressure in the irrigation system and by ensuring proper spacing is used in design and installation.