As the agronomy team at The Olympic Club prepares the Lake Course for the 2025 U.S. Amateur Championship, maintaining consistent soil moisture on putting greens is a top priority. Uniform moisture levels directly contribute to more-predictable, higher-quality playing surfaces. Using the GS3™ ball, we measure putting green firmness as an indicator of playability during every USGA championship. With minimal variation in soil moisture, firmness readings on the greens at the Lake Course have proven remarkably consistent.
During the 2023 renovation of the greens on the Lake Course, director of golf course maintenance Troy Flanagan and his agronomic team worked with the consulting architect and golf course contractor to implement the “variable-depth” construction method. In areas near green perimeters where water tends to collect, the subgrade was excavated to a depth of 20 inches, allowing for 4 inches of gravel beneath 16 inches of rootzone mixture – deeper than the standard 12 inches of rootzone mixture in the USGA recommendations. This design has helped keep perimeter areas as dry as – or slightly drier than – the interiors of the greens, improving both performance and consistency.
Before and during the U.S. Amateur, the maintenance team collects hundreds of soil moisture readings each morning and evening. The data shows that the deeper rootzone areas are playing a key role in maintaining uniform moisture distribution. As part of the USGA Green Section’s daily data collection at the championship, firmness measurements are taken on every green at least once per day. These measurements reveal that the fronts of the greens are often as firm or firmer than the centers, a characteristic less common in greens constructed without the variable-depth method.
To learn more about the variable-depth approach to putting green construction, reach out to your regional USGA agronomist or consult the USGA resource “Building the USGA Putting Green: Tips for Success.” As you watch the championship coverage, pay close attention to ball reactions on the putting green perimeters; you can expect bounce and roll comparable to the middle sections of the greens.
West Region Agronomists:
Brian Whitlark, regional director, West Region – bwhitlark@usga.org
Ross Niewola, agronomist – rniewola@usga.org