Improving Irrigation Uniformity

With no hands up, they knew something needed to be done.

At the August 2009 Cranberry field day, cranberry growers learned about the importance of irrigation uniformity from consultant Steve McCoon of Nelson Irrigation in Walla Walla, Washginton. During the presentation, he asked for a show of hands on how many growers had ever checked their irrigation system for uniformity or measured their sprinkler nozzles for wear.

Cranberry growers rely on irrigation more than most other farmers in BC. Utilized as a distribution mechanism to control pests and diseases, irrigation is also a frost protection tool.

Noting little response to the US expert, the BC Cranberry Marketing Commission asked Mike Wallis P.Ag to lead a survey of irrigation systems on a variety of cranberry fields in BC to not only describe the types of systems used and their age, but also to test for irrigation uniformity and measure nozzles for wear.

Twelve different cranberry farms, representing a diverse range of irrigation systems, were surveyed in Pitt Meadows, Langley, Richmond, Delta and Vancouver Island, The age of the irrigation systems varied from nearly new to 20 years old and field sizes ranged from 2 to 20 acres. Catch cans were used to measure uniformity and a pressure gauge fitted with a pita tube was used to measure sprinkler nozzle pressure.

“We were very encouraged to observe that 86% of the farms surveyed were designed with tail water recovery. This increases the farm’s water use efficiency and reduces their environmental footprint.” observed Wallis. “However, 28% of the survey group water distribution systems required attention to bring uniformity levels to recommended guidelines, so we have some room for improvement.”

Cranberry farmers use the services of certified irrigation designers to design solid set irrigation systems that have a high coefficient of uniformity. The key to keeping that uniformity relies on regular inspection and maintenance. By performing two additional simple, non-technical tests, growers can retain or even improve the performance of their irrigation systems.

“Checking distribution and measuring nozzles is part of our routine now,“ notes grower Allen May of Columbia Cranberry in Richmond, BC. “This project was a real eye opener.”

Funding: $7,805 provided through the former federal-provincial Safety Nets framework. (S0002)