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    1. Erosion Control
    2. Vegetation Management

    Porous “Blanket” Scores a Hole in One at Patriot Hills

    Nov. 1, 2003
    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.”