Quantitative assessment of water quality in the Upper Esopus Creek using fatty acid content of periphyton

Science Center Objects

Problem - The Esopus Creek is located in the Catskill Mountains of New York State and is part of the New York City (NYC) drinking water supply system. The basin was dammed in 1915 to form the Ashokan Reservoir splitting the creek into Upper (upstream of the reservoir) and Lower segments. The Schoharie Reservoir, located 27 miles north of the Ashokan Reservoir, supplies water to Upper Esopus Cre...

Problem - The Esopus Creek is located in the Catskill Mountains of New York State and is part of the New York City (NYC) drinking water supply system. The basin was dammed in 1915 to form the Ashokan Reservoir splitting the creek into Upper (upstream of the reservoir) and Lower segments. The Schoharie Reservoir, located 27 miles north of the Ashokan Reservoir, supplies water to Upper Esopus Creek via the Shandaken tunnel. Waters from the Schoharie watershed enter Upper Esopus Creek at the Shandaken portal and travel 18 km before entering the Ashokan Reservoir. The two reservoirs account for approximately 40% of NYC’s mean annual water supply. Waters from the portal have been the focus of controversy and legal action, however, because they are sometimes turbid and believed to negatively affect local trout populations and water quality. Because impacts that these releases have on aquatic species are speculative, however, stakeholders remain poorly informed about real problems and viable solutions in the Upper Esopus Creek watershed, and often disagree on management of important natural resources.

Objectives - Primary objectives of the study are to:

  • use fatty acid composition of periphyton to characterize local water quality conditions in the Upper Esopus Creek, and
  • determine if fatty acid composition corroborates water quality impacts identified by water chemistry and biological community indicators, upstream versus downstream of the Shandaken portal.

Approach - During summer 2009, the USGS and NYSDEC began a study of periphyton at 20 study sites in the main stem Upper Esopus Creek and its major tributaries. Additional samples were taken from 6 of these sites in November 2009. Periphyton samples will be analyzed for fatty acid content, as well as for ash-free dry mass, chlorophyll a content, and diatom species composition. 

Publications - George, S.D., Ernst, A.G., Baldigo, B.P., and Honeyfield, D.C., 2016, Response of periphyton fatty acid composition to supplemental flows in the upper Esopus Creek, Catskill Mountains, New York: U.S. Geological Survey Scientific Investigations Report 2015–5161, 22 p., with appendixes, http://dx.doi.org/10.3133/sir20155161"

Project
Location by County

Greene County, NY, Ulster County, NY