page_title: Pocantico River
section_title: Ecology and environment
hierarchical_section_title: Pocantico River / Ecology and environment
caption_attribution_description: A weir chamber of the Croton Aqueduct in Sleepy Hollow, New York. These chambers &#8211; another is located in Ossining, New York &#8211; were used to empty the aqueduct for maintanece by diverting the water to a nearby waterway, in this case the Pocantico River. The line could be emptied in as little as two hours, according to a descriptive display at the Ossining chamber. The aqueduct is no longer in use for water delivery, and the right-of-way is now a New York State Historic Park used for walking, jogging and bicycling.
context_page_description: The Pocantico River is a nine-mile-long tributary of the Hudson River in western central Westchester County, New York, United States. It rises from Echo Lake, in the town of New Castle south of the hamlet of Millwood, and flows generally southwest past Briarcliff Manor to its outlet at Sleepy Hollow. Portions of the towns of Mount Pleasant and Ossining are within its 16-square-mile watershed.
  Writer Washington Irving, who lived in the area for most of his life, was inspired by the undeveloped area above the river's mouth to write his classic "The Legend of Sleepy Hollow". Later in the 19th century much of the land was purchased by the Rockefeller family as part of their Kykuit estate; today much of that land has become Rockefeller State Park Preserve. A former reservoir used by the city of New Rochelle has likewise been converted into county-run Pocantico Lake Park. While the river runs predominantly through those parks and suburban land, it is still one of the most polluted tributaries of the Hudson.
context_section_description: The organization Riverkeeper collects samples in three Pocantico River tributaries. The river downstream of Pocantico Lake is a habitat for brown trout. The river is stocked each spring; 540 brown trout were stocked in 2013, and 630 were anticipated to be stocked in the river in 2014. After a bacteria test completed on October 4, 2014, the river was found to have an Enterococcus bacteria count of greater than 2420, indicating high amounts of fecal matter in the water. Other tests of the river quality at the mouth of the river in Sleepy Hollow also contain high levels of Enterococcus bacteria. In fact, the high bacteria counts throughout the river were taken both after wet and dry weather. Dry weather tends to result in lower bacteria counts because less flooding results in less overflow from sewage treatment plants. The high levels of bacteria in the river resulted in beach advisories for the entire river. In 2014, $9.9 million was put aside to repair the Tarrytown sewage treatment plant in order to improve water quality in the region.
  A Westchester County water quality study of the Pocantico River found that the chemical pollutants in the water met most of New York State Standards. The river met state standards on nitrate and phosphate levels, resulting in little cultural eutrophication in the water. Dissolved oxygen levels also met state standards with an average concentration of 9.853 milligrams per liter. Only the conductivity of the water failed state standards with conductivity levels averaging about three times the recommended levels.
  American eels enters the river from the Hudson every spring, moving upstream over the course of one to three years. The eels often accumulate under a dam in Sleepy Hollow, and approximately 10% make it past the dam. The eels move upstream where the habitat is preferable, with lower polychlorinated biphenyl pollution, fewer parasites, faster growth rates for the eels, and a higher percentage of females in the population. Other species in the river include white perch, white sucker, yellow perch, golden shiner, and alewife, only in small numbers.
caption: A weir of the Old Croton Aqueduct in Sleepy Hollow; this weir functioned to divert water to the Pocantico River for aqueduct maintenance
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