Evaluating the Performance of Multiple Alternative Operating Rules under Climate Change: A Case Study of New York City

Abstract

An increase in climate variability due to increased greenhouse gases in the Earth's atmosphere poses challenges for water management. Current operating rules for the New York City Water Supply System (NYCWSS) are designed to manage water levels and mitigate the effects of extreme precipitation on the quality of water provided to the end user. Questions remain as to whether these rules will continue to be robust under future climates. A screening tool simulating the operations of the NYCWSS is developed, which couples with a hydrology model developed in part with the New York City Department of Environmental Protection (NYCDEP). To observe operating rules and alternatives under varying climate, this study used a stochastic weather generator to create a number of long time-series to test the system. Parameters used in the weather generator were incrementally varied. In all cases, the change incurred by a changing climate is larger than the change effected by small operational changes, though overall reliability is not threatened. These preliminary screening results will allow NYCDEP to focus on the rule changes and climate futures of greatest interest to them.