Potential Impacts of Changes in Climate on Water Quality in New York City's Ashokan

ACKNOWLEDGEMENTS Dr. Richard Palmer for his guidance throughout my time in graduate school and his leadership and expertise on this project. Dr. Casey Brown for inspiring this project's methods and for his encouragements to pursue an advanced degree at UMass. Leslie DeCristofaro for building STATS and her helpful cooperation in the design and completion of this project. Scott Steinschneider for allowing me to use his weather generator model and also his advice on the project framework and assistance with R. Matonse from the NYCDEP for allowing the use of their GWLF model as well as their invaluable feedback, advice, and sharing of data and information throughout the project. Abstract This thesis investigates an approach for determining water resources vulnerability caused by climate change and applies it to a case-study for the New York City Water Supply System (NYCWSS).The results provide potential responses of the system to changes in climate and guidance that can inform short and long-term planning decisions. This research models the hydrology and operations of the NYCWSS and includes a statistical model of turbidity concentration in the Ashokan Reservoir. Using a stochastic weather generator, incremental changes are made to precipitation and temperature and used to drive the coupled hydrology-simulation model. The results are aggregated and examined to show the sensitivity of the system, and in particular Ashokan Reservoir turbidity, to changes in climate. The results are briefly compared with the latest GCM data to provide insight into expected changes in turbidity over the next half-century.