Positioning the 2024 Drought in New York City’s Drought History: A Demand-Sensitive Framework for Assessing Risk

New York City’s water supply system serves more than 9 million people. Managing this system requires balancing multiple objectives associated with ensuring reliable drinking water, supporting ecosystems, and meeting downstream obligations. The 2024 Drought, triggered by the second-longest dry streak on record, revealed the City’s vulnerability to flash droughts that can quickly stress operations. This white paper situates the 2024 Drought in a 74-year historical record of streamflow-based droughts. Using a demand-sensitive drought index derived for feeder streamflow sites of the Pepacton, Cannonsville, and Neversink reservoirs (i.e., limited to Delaware System), we tracked the event’s duration, severity, flashiness, and recovery. The analysis shows that the 2024 Drought spanned 87 days, produced a cumulative deficit of 22,251 million gallons, exhibited extreme flashiness of 490 million gallons of deficit per day, and recovered from its peak severity in 20 days. Six deficit days during this event ranked among the top 100 on record, placing the event in the top ten percent of all droughts since 1951 for the combined Pepacton, Cannonsville, Neversink feeder streamflow sites. When examined seasonally, it stood out even more, ranking in the 95th percentile among all September–October–November droughts, confirming its unusual and consequential nature. The 2024 Drought was short-lived, ending in early January 2025 after significant rainfall restored water levels. Yet its timing, flashiness, and operational consequences make it a historically significant hydrologic shock. As climate change intensifies the Earth’s water cycle, New York City must prepare not only for prolonged droughts but also for emerging flash droughts.