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‘Sprinkles’ DeGrasse writes, ‘Why do courses in rainy climates need irrigation systems?’

By: Jeffrey D. Brauer


Even typically wet climates experience dry periods, often right in the summer play season. Irrigation is easily understood in desert environments, but is also necessary in higher rainfall areas, like Seattle, which averages 41 inches of annual rainfall and has turf water demand of 27 inches per year. However, in summer months, turf needs 12.31 inches of moisture, but Seattle averages 7.85 inches of rainfall, so even courses there experience rainfall deficits and require irrigation.

Since courses use locally adapted turf types, most climates require an irrigation system that delivers 1-1.5 inches per week under normal operations. By extending watering times a few hours, most systems can deliver up to 2 inches per week for the hottest, driest periods, risking some golfer inconvenience.

Many golfers don’t realize that even large lakes would be pumped dry without a refilling source. Proposed golf courses need to find, permit and develop a reliable irrigation-water source before construction. Without this, they can’t secure financing. It’s not about “green” as much as it is “greenbacks” – protecting the lender's major investment.

Irrigation water comes from a combination of sources, including municipal water, wells, water capture from streams and/or lakes, and effluent.

Potable water is increasingly rare as the sole irrigation source. Accessing the municipal water supply is technically easy, if a suitable pipe is nearby. But it’s politically difficult. It’s likely to be cut off during droughts, exactly when the course needs it most. It’s also extremely expensive.

Wells are usually an excellent irrigation-water supply, if they can produce a volume of 300 to 1,000 GPM. Wells cost $30,000 to $300,000, but even with relatively high initial cost, they pay for themselves by providing inexpensive water for the electrical cost of pumping. Some well water has harmful materials – like sulphur, heavy metals, calcium carbonate, and/or salt that, without additional treatment, can damage irrigation equipment, turf, or plants.

We are seemingly returning to old ideas of capturing rainwater for sustainability. Surface water has variable quality – both urban areas and farms have contaminated golf course water supplies. Even if we can locate an irrigation reservoir to capture enough water, siltation causes problems. Further, most states own and regulate surface waters, so you may not “own” the water that crosses your property anymore!

Effluent is increasingly popular. In the United States, most effluent is treated to drinking-quality levels, owing to Federal regulations. I have seen the engineer of an effluent plant drink a glass of it to prove the point! The biggest drawback is whether there is an economical connection. Running a large supply line several miles may costs millions.

Sometime this century, golf courses will probably concoct a variety of irrigation supply sources. They will “make do” with less quantity and quality of irrigation water than now, accepting less-than-perfect turf conditions in outer areas. This may resemble “the old days,” where brown, summer roughs were normal. The 1970s to 1990s may have been a short-term anomaly, when irrigation made golf courses “perfectly green” throughout.