Pepacton Reservoir, the largest reservoir by volume in the New York City Water Supply System, lies in Delaware County along the northern edge of Catskill Park, five miles south of the Village of Margaretville and more than 100 miles northwest of New York City. Completed in 1955 by damming the East Branch of the Delaware River, it is approximately 15 miles long, holds 140.2 billion gallons at full capacity, and collects water from a watershed of 371 square miles. As one of four reservoirs in the city's Delaware Water Supply, it normally contributes more than 25 percent of the total daily water flow into New York City. Water from Pepacton enters the East Delaware Tunnel, flows 25 miles southeast to Rondout Reservoir, mixes there with water from the Cannonsville and Neversink Reservoirs, then heads south through the 85-mile Delaware Aqueduct, the longest continuous tunnel in the world, before ordinarily passing to the West Branch and Kensico Reservoirs east of the Hudson River and then to Hillview Reservoir in Yonkers for distribution through New York City's water system. The Catskill region watershed helps fill six reservoirs, which together with 13 reservoirs and lakes in Westchester and Putnam Counties supply 1.3 billion gallons of water each day to 9 million people in New York City and its northern suburbs. This water is of very high quality, but it faces threats from non-point source pollution such as chemicals, sediment, pathogens, and nutrients washed from fields, barnyards, roads, and parking lots during rain, storms, and snowmelt. In 1997, an agreement among New York City, upstate towns, counties, and villages, the U.S. Environmental Protection Agency, New York State, and the environmental community established programs funded by the city to replace septic systems, build wastewater treatment facilities, provide sand and salt storage buildings, fund educational projects, support appropriate economic development, institute new land use regulations, and purchase additional lands important for water supply protection, while separate programs created under a 1994 partnership with the watershed agricultural community help farmers and forest landowners protect water quality while preserving their way of life.