Understanding How It Really Works
Have you ever wondered why SCR tends to dry out and areas begin to turn brown throughout the course? Have you ever wondered if our irrigation system is at fault? Before the Rainbird Irrigation System gets the blame, I would like to give a more in-depth look into the course make-up and how our irrigation system fits into the equation.
Did you know that SCR is completely sand capped? What does this mean some may ask. There is over 300 acres of maintained turf grass at SCR. Under it lies 6 inches of sand that has capped the existing soil. This was brought in during the construction of the golf course to provide an experience like none other in the area.
The sand provides a state of the art drainage to the entire course even after the most severe rainfall events. You have probably thought after heavy rains, "Wow, I am amazed at how fast the water drained off." This is 100 percent due to the sand cap.
Although this sand cap provides us the best possible chance of being off the path and back to play quickly after these type of events, it also has its cons. During periods of drought, our course dries down much faster than a native soil course would. Native clay soils are able to hold moisture for extended periods of time, providing adequate moisture to the plant growing in it. In sandy soils, there is a need for much more frequent irrigation or rainfall events to provide the plant with proper moisture. In many cases during prolonged periods of no rainfall, sandy soils will become hydrophobic. This causes the surface to seal off, not allowing any water to penetrate the canopy. We are able to break this hydrophobicity with the use of penetrant wetting agents. These wetting agents are sprayed monthly to ensure our irrigation will get to the plant's roots.
So now that we understand the soil profile that lies underneath SCR, it is also important to understand the physical properties of the grass that grows on top of it. SCR's rough is Palisades zoysia. Palisades is known for its aggressive growing habits as well as its ability to survive in more shade than many other turf grass species. The Palisades has the ability to tolerate more extreme drought conditions because of its ability to recover faster.
Our fairways at SCR are grassed with Meyer zoysia. Meyer is known for its ability to be managed at lower mowing heights and its slow growth habits. Both of these traits are ideal for teeing grounds and fairways. However, it is also known for its inability to withstand drought conditions. During periods of drought, the Meyer zoysia leaf blades will lose its turgor and will shrink in size opening up the canopy. As the canopy opens, the underlying soil is exposed to wind and sun, furthermore drying out the root system of the plant.
All plants during periods of stress will shut down and go into a dormancy stage. Most people only associate dormancy with cold; however, this is the plant's natural response to any stress put on it. When a plant shuts down and enters dormancy, it no longer takes up the adequate moisture or food it needs to recover. Only mother nature can break a plant's dormancy.
Understanding the needs of the turf grass species used at SCR, as well as what lies underneath, gives us a better understanding of how our irrigation should work in perfect conditions. There are over 1,000 sprinkler heads on SCR property. Each head can throw approximately 80-90 feet at 110-120 psi. Each head on property was spaced so that it would throw back to the closest sprinkler head giving adequate coverage.
As one could imagine, it takes some serious power to pump this much water out on the course. Our irrigation reservoir is the lake located on No. 6. This lake is fed by a well that was installed in 1997 that would revive the lake as we irrigate the course. The water is then pumped from No. 6 lake by three 75 HP pumps that can provide 2,400 gallons per minute to the course. Although the pumps can supply 2,400 GPM, the flow is greatly restricted by pipe sizes, amount of heads running, and in some cases the availability of water.
During normal weather patterns, we average 300-600 thousand gallons of water pumped during an irrigation cycle from 9 PM to 5 AM. During extreme periods of drought, we will pump 600-900 thousand gallons of water a night. Often times when the course is closed on Mondays, we are able to delay the shut off time and irrigate over 1 million gallons of water to the course.
Over the past seven years, myself and the staff at SCR have committed to eradicating the "mud ball" that was so prevalent to SCR. I feel we have made great strides with aggressive aerification, as well as minimizing excessive watering. We have incorporated more hand watering and the use of staff watering only areas that are in need in the middle of play. As a result, our tees, fairways and rough will brown out and become dormant at times. We have seen time and time again that after an adequate rainfall event, the plant responds and heals as it should. In extreme cases, we have had to re-grass certain areas that the canopy thins and becomes too severe to grow in.
Please be sure to check out this letter from USGA Senior Agronomist Chris Hartwiger that further explains how sand capped courses react in drought conditions.
The information above was compiled along with letters from Chris Hartwiger, USGA Senior Agronomist, as well as Dr. Michael Goatley, Virginia Tech University Extension Agent, detailing their professional opinions on SCR as in terms of irrigation.