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Just as lakes,
wetlands, and other water hazards add to the challenge
for golfers, they also test the skills of golf course
builders. Unless bare soil is protected from erosion
caused by stormwater, snowmelt, or irrigation runoff
during construction, sediment can wash off-site. The
steeper and longer the slopes and the more erodible
the soils, the greater this threat. In addition to affecting
downstream water quality, such sediment pollution also
violates National Pollutant Discharge Elimination System
construction permits and poses the risk of costly fines
or a shutdown of the project.
It was against
this background that Turco Golf Builders of Suffern,
NY, began construction of Patriot Hills Golf Course
in Stony Point, NY, in the summer of 2001. In addition
to attracting local Rockland County golfers, the 18-hole
municipal course is convenient to the New York City
metropolitan area and northern New Jersey.
The irrigated
bent grass fairways traverse 6,600 yd. of hilly terrain
and are surrounded by Kentucky bluegrass primary roughs
and fescue buffalo grass secondary roughs. Elsewhere,
numerous rock walls, exposed during construction, accent
the landscape, which offers views of the Hudson River
in several locations.
"There's
a lot of elevation change throughout the course," describes
Joe Smyth, CGCS, superintendent of Patriot Hills. "On
four holes, it changes 100 feet or more from tee to
green. The degree of slope is three-to-one or steeper
on at least half of the fairways and even steeper on
the roughs. Some of the slopes are as long as 150 yards.
Erosion was a major concern in building the course."
The easily
dispersed clay particles in the clay-loam soils added
to this concern. So did the water features: a pond on
one hole and a total of about 4 ac. of wetlands around
two other holes. In all, about 20 ac. of slopes on fairways,
roughs, and areas around greens, tees, and bunkers at
Patriot Hills call for measures to limit sediment loss
due to runoff.
When it comes
to controlling erosion, grass and other vegetation are
naturals. Leaves and stems absorb the energy and soften
the erosive impact of raindrops, reduce the amount of
runoff by intercepting it to infiltrate into the ground,
and slow the flow of runoff to promote sediment deposition.
Meanwhile the root systems help anchor the soil.
Because of
the slope lengths and gradients at Patriot Hills, covering
seeded slopes with loose straw or hydromulch would have
been ineffective in controlling erosion. On a previous
golf course construction project, Smyth installed sod
to establish a quick, permanent protective cover. But
for this project, costs of sod exceeded the erosion
control budget. Rolled erosion control blankets were
another option. In addition to the labor required to
install the blankets, staples used to secure them must
be removed later. Also, depending on the type of product,
netting can interfere with mowing. In fact, erosion
control blankets were installed on several small areas
early in this project. However, the expense of covering
all the critical slopes ruled out this alternative.
Smyth examined
a less costly approach, one he had never used. He tested
two different brands of spray-on erosion control products.
One was a conventional bonded fiber matrix (BFM)
"Compared
to the other choices, we felt it was the most cost-effective
way to achieve quick germination and control erosion,"
he explains.
"Material
and installation costs of the product are about half
those of sod," says Dick Grant. His company, Chesapeake
Turf LLC in Salisbury, MD, handled the seeding and erosion
control work on the project. As he points out, the porous
blanket allows turf to grow up through the matrix of
fiber and conforms closely to humps, dips, and other
surface irregularities for maximum soil protection.
The product
also offers several advantages over conventional BFMs,
Grant notes. In addition to a chemical bonding of wood
fiber and soil particles, the crimped and interlocking
wood fibers create a mechanical bond for enhanced erosion
control. These fibers absorb the impact energy of raindrops
and hold 50% more water, retaining up to 15 times their
weight in water. That reduces stormwater runoff and
transfers more moisture to the seed bed, improving germination
and turf establishment.
Whereas conventional
BFMs can require about 24-48 hours after application
to cure and to fully control erosion, the M-BFM is effective
almost immediately. "You don't need a two-day window
between application and rain," Grant says. "Once you
get the seed down, the soil and seed are protected,
allowing you to finish the job more quickly."
In a series
of trials at San Diego State University, one test simulated
a 10-year storm event in which a fully cured, 3,000-lb./ac.
application of the M-BFM reduced erosion by nearly 100%
compared to bare, untreated soil. In three consecutive
simulated 50-year storm events, a fully cured, 3,500-lb./ac.
application also reduced erosion by nearly 100%. When
applied at the minimum rate of 3,000 lb./ac. and allowed
to cure for two hours before it was subjected to a simulated
10-year storm event, the product reduced erosion by
98%. In other tests, researchers at Utah State University
compared performance of the patented Conwed Fibers product
to conventional BFMs and rolled excelsior and straw
erosion control blankets. The M-BFM was more effective
in reducing soil loss and water runoff and in increasing
seed germination rates and the amount of vegetation
produced.
Chesapeake
Turf completed seeding and erosion control at the Patriot
Hills Golf Course between the first of August and the
end of November. The M-BFM was applied with seed and
fertilizer at an average rate of 3,800 lb./ac., covering
about 11.5 ac. a day. A hot, dry summer and fairly
normal fall weather was followed by above-average rainfall
the rest of the seeding period, Smyth reports. The weather
included several storms in which 1 in. or more of rain
fell within about two hours.
"The Conwed
product performed really well, and there was little
runoff from the storms," he says. "As expected, the
seed germinated in about five to six days and produced
a good, uniform stand."
Grant recalls
one three-quarter-inch rain event in August. "The rain
was heavy enough to create washing in untreated areas,
but there was no washing whatsoever where we applied
the M-BFM."
"In addition
to controlling erosion on the banks of a pond and around
wetlands, the product also prevented seeds in the roughs
from washing onto the fairways and the sand traps,"
adds general contractor Dennis Turco.
"The M-BFM
is a nice alternative for controlling erosion if you
don't have the budget for sod," concludes Smyth. "I'd
use it again."
EC
- November/December 2003
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