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April 12, 2016

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Department of Environmental Protection to Use Natural Weed Control Along City-owned Roads in the Watershed

Scientific pilot test shows natural control method will be effective for guiderail maintenance

The New York City Department of Environmental Protection (DEP) on Tuesday announced that it will begin using a natural weed control for roadside maintenance in the watershed. The move toward an all-natural herbicide comes after a 2015 pilot test that examined the effectiveness of two natural products for controlling weed growth along roadway shoulders, especially where guiderails are located. That test, performed by water quality research scientists and water supply operations staff, found that one of the natural herbicides effectively eliminated 98 percent of weeds.

“Last year, we promised local residents in the watershed that DEP would suspend the use of synthetic herbicides for road maintenance and examine the effectiveness of alternatives that were natural and less toxic,” DEP Commissioner Emily Lloyd said. “We are happy to announce that our test has shown good results, and that DEP will move toward using one of these natural alternatives for controlling vegetation where guiderails line City-owned roads in the watershed. This outcome balances public safety, environmental stewardship, water quality protection, and the concerns of our neighbors.”

From 2009-2014, DEP had contracted with the state Department of Transportation to apply a synthetic herbicide called glyphosate along guiderails on City-owned roads in the watershed. New York City owns 99 miles of roads that run along the perimeter of its reservoirs and some watershed lands. The use of glyphosate was approved by the U.S. Environmental Protection Agency, and extensive scientific testing and water quality monitoring found that it had no effect on nearby bodies of water, including City reservoirs.

The use of glyphosate for roadside maintenance was suspended in 2015 after watershed residents urged DEP to seek more natural alternatives for weed control. Last summer, DEP conducted a pilot test for two natural herbicides called Burnout II and Finale. Both are natural, non-synthetic products that are also approved by federal authorities. Burnout II is an organic mixture of clove oil and citric acid. Finale, also known as glufosinate, is a natural compound based on two types of fungi typically found in soil.

On July 6, 2015, both natural herbicides were applied to four 100-yard lengths of roadside near Ashokan Reservoir. One test area was located along Route 28A near the Ben Nesin Lab building, and the other location on Route 28A between Whispell Road and West Shokan Heights Road. These locations were chosen because they offered different vegetation and different exposures to sunlight. Adjacent control areas were left untreated for comparison.

Research scientists and operations staff made weekly and monthly observations after each of the areas were treated with the natural herbicides. These observations continued until Oct. 6. Finale was found to be the most effective, eradicating approximately 98 percent of weeds in the treatment area; very little regrowth was seen during the observation period. Burnout II was found to only kill less than 5 percent of the weeds.

As a result, DEP will adopt the use of Finale on a pilot basis in 2016. The product will be applied by the state Department of Transportation beneath the guiderails on all City-owned roads in the Catskill and Delaware watersheds. DEP will also purchase a quantity of Finale for the state to apply along guiderails on state-owned roads located along the boundaries of New York City’s reservoirs. DEP will closely monitor the effectiveness of Finale as it is applied watershed-wide for the first time.

The maintenance of guide rails is important for public safety and proper road drainage in the watershed. Tall weeds can reduce sight distances for drivers, especially along bends. Uncontrolled growth along the guiderails can also make it difficult for motorists to see and avoid deer. Dense weed growth can lead to ponding along the roadsides, which causes pavement to crack and form potholes over time.

DEP manages New York City’s water supply, providing more than one billion gallons of high quality water each day to roughly 9.5 million New Yorkers. This includes more than 70 upstate communities and institutions in Ulster, Orange, Putnam and Westchester counties who consume an average of 110 million total gallons of drinking water daily from New York City’s water supply system. This water comes from the Catskill, Delaware, and Croton watersheds that extend more than 125 miles from the City, and the system comprises 19 reservoirs, three controlled lakes, and numerous tunnels and aqueducts. DEP has nearly 6,000 employees, including almost 1,000 scientists, engineers, surveyors, watershed maintainers and other professionals in the upstate watershed. In addition to its $70 million payroll and $157 million in annual taxes paid in upstate counties, DEP has invested more than $1.7 billion in watershed protection programs—including partnership organizations such as the Catskill Watershed Corporation and the Watershed Agricultural Council—that support sustainable farming practices, environmentally sensitive economic development, and local economic opportunity. In addition, DEP has a robust capital program with nearly $14 billion in investments planned over the next 10 years that will create up to 3,000 construction-related jobs per year. For more information, visit, like us on Facebook, or follow us on Twitter.

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NYC Department of Environmental Protection
Public Affairs

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