Hand watering greens and approaches is a common practice at the U.S. Open so that moisture can be carefully controlled to produce the desired firmness while protecting the health of the turf. The hand watering crew at The Olympic Club did an amazing job last week of maintaining uniform soil moisture with the use of portable moisture meters to check the greens and approaches in the morning and evening along with a very regimented hand watering process. Their goal was to water as necessary to maintain 20 to 22 percent soil moisture, which was just enough to get the greens through the day until they could be checked and watered in the evening.
The hand watering crew of Andrew Crawford, Miles Lilja, Jeremy Galvin and Tyler Mackenzie took the program one step further by using colored irrigation flags to designate sections of greens that needed extra water and other areas that needed no water at all. A daily threshold was established based on weather patterns and evapotranspiration (ET) readings from the weather station. As each team probed the greens with the moisture meter, a red flag was placed where soil moisture was below the threshold (generally 15 percent and below), a yellow flag used in spots that measured at the threshold (usually 16 to 20 percent moisture), and a blue flag designated areas that did not need supplemental watering (above 25 percent moisture). Then the team would hand water the green in a very uniform pattern with the goal of covering 1,000 square feet per minute, skipping over areas that did not need water and giving extra to areas that were below the threshold.
This program resulted in outstanding uniformity on each green and from green to green throughout the course.
Source: Pat Gross email@example.com