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Why is My Golf Course So Wet?
By David L. Wienecke and Patrick J. Gross
During hot, dry summer conditions, many assume golf courses would be dry and firm. Based on recent USGA Turf Advisory Service visits to golf courses in California and Arizona, this assumption is not true, as we have heard golfers complaining of wet playing conditions. Here are some explanations and suggestions to address wet summer golf course conditions:
Irrigation system problems - Some irrigation systems (especially those 15 years or older) lack uniform coverage due to nozzle wear, improper sprinkler spacing, programming problems, or system design inadequacies. To compensate for coverage gaps, superintendents have to over-irrigate by 10% to 20% to address the dry areas. This is especially true when there is an expectation for exceptionally green golf course conditions.
The current standard for precision application of irrigation is based on water replacement lost from rootzone evaporation (i.e. due to heat and wind) and from the plant transpiration (i.e. plant water loss through the leaves) collectively called evapotranspiration or ET. Any part of the irrigation system not functioning properly will compromise irrigation efficiency, typically resulting in wet and dry areas on the golf course.
Even with a state-of-the-art system, making daily adjustments to the computer and field satellite controllers is essential to maintain healthy turf and good playing quality. Failure to fine-tune the system daily will typically result in over watering. While most systems deliver water exactly as programmed, unfortunately, these systems do not think for themselves.
Here are some guidelines for resolving summer irrigation problems:
- Identify sprinkler precipitation rate and spacing distance between heads by performing a catch can test. Improperly installed sprinklers are the most common reason for poor coverage. Spacing distances from 70' to 90' will tend to have more over watering problems compared to distances from 50' to 65'.
- Provide individual sprinkler control. Block systems (i.e. two or more heads controlled per station) frequently result in over watering due to the lack of individual sprinkler control. There is a direct correlation between the number of sprinklers in a station block and the lack of precision irrigation application. Individual sprinkler control also is essential for proper watering of different grass species and mowing heights. As an example, the irrigation requirements for putting surfaces are different from putting green surrounds. One sprinkler cannot properly irrigate both areas without over watering one of them.
- Golfer and public education are needed to reduce the pressure on turf managers for producing lush green turfgrass. These pressures will inevitably lead to over watering simply as a way to maintain employment.
- It is typical to see golf courses that are over watered when the superintendent is on vacation or away from the course. Superintendents report that proper watering is one of the most difficult skills for employees to learn.
At many golf courses, summer is a period when golfing pressure is high from dawn to dusk. More golfing rounds in a day result in a reduced number of hours available to apply the higher water volumes needed to avoid extreme drought stress. Golfers playing first thing in the morning may find the golf course too wet due to the shortened number of hours available for drying time following an irrigation cycle.
Soil and water problems - Wet golf course conditions can be a result of poor drainage. Inadequate infiltration and percolation can be caused by limited soil porosity, excess sodium or bicarbonate in the irrigation water, dense organic matter (i.e. thatch) layers, or physical compaction from traffic on dense clay soils. The following programs can help address soil and water quality problems that are contributing to wet summer conditions:
- A laboratory analysis of soil and water quality is an important first step to evaluate potential problems that may contribute to poor drainage. A combination of chemical amendments and core aeration is often recommended to correct water quality soil drainage problems. Additional leaching is typically needed to remove salts from the rootzone in salt affected turf. Leaching requires 5% to 10% additional irrigation or more compared to non salt-impacted water supplies. While this may appear as over watering, it is an essential program to sustain healthy turf growth during the summer.
- Thatch layers must be eliminated to correct organic matter induced drainage problems. Vertical mowing, sand topdressing, and core aeration will help provide adequate infiltration and percolation.
- Concentrated wear areas require cultivation and traffic control measures, such as the use of curbs, ropes, and signs. Rotate traffic patterns daily to prevent this problem. Unfortunately, once traffic problems create water ponding and poor drainage, it is too late to change traffic patterns. Improvement requires cultivation to restore proper drainage.
- Compacted native soils or shallow soils over solid rock may never drain properly without excavation, cultivation, or capping with 6" of sand to provide adequate infiltration and percolation.
Turf establishment and renovation issues - Some courses schedule renovation projects during the summer - either by choice or necessity - to restore uniform turf coverage. Courses with weak bermudagrass coverage following years of winter overseeding take advantage of the hot summer temperatures to seed, sod, or sprig new bermudagrass into bare areas. The extra water necessary to establish the new bermudagrass contributes to wetter-than-normal playing conditions.
Heat stress on cool-season grasses - Cool-season grasses, such as Poa annua, creeping bentgrass, and perennial ryegrass, require extra water during the summer to cool the plant and avoid heat stress. Syringing and spot watering become necessary as temperatures rise above 90° F to keep the cool-season grass alive. This is another possible explanation for wet golf course conditions during the summer.
Conclusion - While most golfers prefer dry, firm playing conditions, there are obviously extenuating circumstances that require superintendents to over-irrigate the course during the summer. It is possible to minimize these problems by addressing irrigation system performance, soil and water quality issues, and explaining to golfers the reason why extra water is occasionally applied to the golf course. Hopefully, excessive wetness is only a temporary problem that can be eventually resolved by implementing some of the suggestions outlined in this article.
Source: David L. Wienecke, dwienecke@usga.org or (714) 542-5766.
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