Author(s): Dorothy K. Hall; Allan P. Frei; Nicolo E. Digirolamo; James H. Porter; George A. Riggs
Keywords: No Keywords
Abstract: The New York City (NYC) Water Supply System provides over one billion gallons of water per day to NYC and numerous upstate communities through a system of reservoirs and tunnels located primarily in the Catskill Mountains region of southeastern New York State. Fractional Snow Cover (FSC) derived from standard Moderate-resolution Imaging Spectroradiometer (MODIS) daily, cloud-gap-filled snow-cover maps, along with observed temperature, precipitation, and streamflow are analyzed for each of the water years from 2000–2001 through2010–2011 in the Ashokan and Cannonsville basins of the Catskill/Delaware Watershed. We show that snow can melt suddenly (often due to rain-on-snow (ROS) events) causing a spike in streamflow. In some years a snowpack will form and melt several times during the winter. The Cannonsville has more snow and a higher FSC compared to the Ashokan, and snow-related flooding is more prevalent than in the Ashokan. Flooding can impact reservoir operations for the NYC water supply. Potential changes to the temperature and precipitation regime during the 21 century may affect the frequency and magnitudes of such events.