Abstract
My research examines the infrastructure projects supporting climate resiliency for New York City’s drinking water supply in association with extreme weather events. The Department of Environmental Protection has undertaken extensive efforts to address water management issues related to heavy rainfall events, which are projected by Global Climate Models to increase in frequency and intensity in the future. Project details include the most recent scientific projections for climate change scenarios for the Catskill/Delaware watershed and the hydrological implications of extreme weather events on New York City’s water supply system. My research methodology included a literature review of drinking water resources for New York City, the above-mentioned climate trajectories and hydrological effects, and historical and contemporary infrastructure projects engineered by the Bureau of Engineering, Design, and Construction and supported by the Bureau of Water Supply. Inquiry and discussion with scientists at the Bureau of Water Supply’s Hawthorne Laboratory further supported the review.
As concluded by researchers within the Bureau of Water Supply, the Catskill/Delaware watersheds are expected to experience several changes during 2041-2060, relative to 2001-2020. Changes include increases in annual average air temperatures and precipitation, decreases in annual average snowfall and snowpack accumulation in the Ashokan watershed, and increases in rate of streamflow to Esopus Creek from December through mid-March and decreases in streamflow from March to April. While turbidity in the Catskill/Delaware watershed is projected to increase slightly, turbidity in the diversion from Kensico Reservoir is expected to remain at its current baseline. The New York City water supply system shows high resiliency, reliability, and has a minimal risk of vulnerability to consecutive annual failures.
Climate resiliency measures have historically been built into the water supply system and continue to be integrated through the New York City Department of Environmental Protection’s infrastructure optimization projects. To increase operational redundancy and adapt to extreme weather events, several capital investment projects are underway. Once connected to the Delaware Aqueduct during the 2022-2023 shutdown, the Rondout-West Branch Bypass Tunnel will be capable of providing a continuous drinking water supply well into the mid-century. The Catskill Aqueduct Rehabilitation encompasses preparations for the Delaware Aqueduct shutdown through maintenance and repairs. Completed projects such as the Shaft 4 Connection and the Ashokan Dividing Weir and Restoration have provided operational flexibility to the water supply system. Additional projects planned include the Kensico-Eastview Connection, Hillview Reservoir upgrades, and the Ashokan Century Program. Collectively, these projects support the long-term sustainability of the system.