It is hard to believe that recently Hurricane Irene was driving up the Atlantic seaboard and bringing with it hurricane and tropical storm force winds and flooding rains. Add Irene to the list of 2011 maladies that include winter damage, tornadoes, giant hail, and an earthquake tremor. Enough is enough already. I guess most of us should be thankful that Irene lost some of her strength before making landfall and spared us from even worse wind and storm surge damage. However, the large and powerful storm will be remembered most for the catastrophic flooding and damage it has caused throughout the region.
Maintenance staffs have been busy cleaning up downed trees, branches and debris left from the wind and massive flooding, along with washed out bunkers and cart paths, severe erosion and flooded turf areas. Saltwater flooding and, to a lesser extent, salt spray are the major concern for lower lying coastal golf courses. Saltwater flooding is never good, but poses an even greater risk in the summer when the turf is actively growing. The extent of damage is hard to predict and will depend on the weather, turf species and cultivar, duration of the flooding and ability to remove the accumulated salts. Toxic levels of sodium and chloride ions will damage most cool season grasses and especially annual bluegrass. Consider the following points as you plan a clean-up and recovery strategy following the storm’s aftermath.
- Record rainfall totals generated from this storm have caused more extensive flooding and erosion on inland golf courses. The duration of the flooding and temperature will impact the turf survival. Turf under water for several days will probably be ok if the temperatures do not climb too high. Removing silt and other debris left from the flood will be the challenge. Use snow shovels or power broom the silt and debris from greens and use hoses to wash-off as much of remaining soil as possible. Plan on extra cultivation in the flooded areas this fall to remove layers of silt and other fines from the surface.
- Golf courses that experienced saltwater flooding must anticipate the worst in regards to turf damage. Any rain that occurred after the saltwater receded will be helpful. Begin irrigating the areas as soon as possible. Check the salinity of any irrigation pond that may have been breached. Water with an ECw of 2-3 dS/m (1280ppm-1920ppm total dissolved salt), although not ideal, can still be used to flush salt-affected sites. Water with higher salt concentrations should not be used.
- How much water will it take to remove salts from the upper regionalUpdateContent zone? Mike Huck, Irrigation and Turfgrass Services in Dana Point, CA relayed to me that 4 inches of infiltrated water will remove 90 percent if the salt from 4 inches of soil, regardless of the soil texture. Gypsum can be applied at 10 lbs per 1,000 sq ft while leaching the salt-affected areas. Reapply gypsum at 10 lbs per 1,000 sq ft when the areas can be cultivated.
- Use a salinity meter (see links below) or have a saturated soil test completed to determine if the salinity has been lowered sufficiently for seeding. ECe (electrical conductivity of soil) should be < 4dS/m and preferably < 2 dS/m and an SAR < 6 and preferably < 3 for successful seeding. Bentgrass cultivars such as Seaside II, Cobra, SR 1020 and Mariner have higher salt tolerances and may be a consideration for flood prone greens and other areas. The perennial ryegrass cultivars Brightstar SLT, Citation II, Citation Fore and Paragon offer higher salt tolerance, Alkaligrass grass can tolerate higher levels of salt and may also be a suitable choice for areas that are more prone to saltwater flooding.
- The warm blast of tropical air generated from this storm may also carry with it the threat of gray leaf spot disease. I have not yet heard reports of the pathogen in the Northeast, but stay alert for reports of disease activity and for symptoms on perennial ryegrass.
This hurricane will not be remembered so much for its wind, as it will for the widespread flood damage. The clean-up, repair work and regrassing efforts at many Northeast golf courses will be significant. More details regarding the damage and clean-up efforts will be forthcoming as we better understand the extent of damage. Do not hesitate to contact us if we can answer any questions or be of help during the recovery efforts.
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Know When To Over Irrigate, Vermeulen, Paul H. 1997. USGA Green Section Record. September/October. 35(5): p. 16 /content/dam/usga/pdf/imported/course-care/970916.pdf