A concerning issue is emerging with the suburban reservoirs that supply 10% of New York City’s celebrated drinking water. These sources are becoming increasingly salty due to the consistent use of road salt in the surrounding areas, and if this trend isn’t reversed, the reservoirs might eventually be deemed unsuitable for water supply, city authorities warn. This issue may not necessitate an immediate shutdown, as it isn’t expected to reach a critical point until the early next century. However, the increasing salinity poses a potential risk to the renowned quality of New York’s tap water, often compared to champagne, thereby presenting challenges for managing a system that serves over 9 million people.
Rohit Aggarwala, New York City’s environmental protection commissioner, highlighted the concerns derived from their findings. “Should we fail to adapt, by 2100, the Croton Water System may merely become a recreational locale, no longer a viable water source,” Aggarwala expressed, indicating potential ramifications for New York City water consumers. Developed in 1842 with the first Croton Aqueduct channeling water to Manhattan’s Central Park reservoir, the Croton system now constitutes 12 reservoirs and three regulated lakes situated north of the city.
According to a recent study, chloride levels—a measure of salinization—increased threefold from 1987 to 2019 within the system’s primary reservoir, located roughly 20 miles north of the city boundary. Forecasts show these concentrations could surpass the state’s permissible chloride levels by 2108. Though salinity issues are widespread in New York’s upstate reservoir systems, they are notably less prevalent in the Delaware and Catskill watersheds, west of the Hudson River, which provide about 90% of the city’s water. This disparity is likely due to minimal development in these areas.
The main culprits behind this increasing salinity are road salt, sewage treatment discharges, and water softeners. Each winter, millions of tons of rock salt are used on American roads to enhance safety by reducing icy hazards. Shannon Roback, the science director at the environmental organization Riverkeeper, marked this as a nationwide concern, especially in snow-prone regions. The rising salt levels have been consistent across the Northeast, Midwest, and other areas employing road salt. Roback cautioned that elevated salt levels pose several environmental risks and health concerns for individuals on low-sodium diets.
Aggarwala outlined potential solutions, including the removal of salt using reverse osmosis systems. While effective, this technology is costly and energy-intensive. Alternatively, Croton water could be mixed with less salty water from other watersheds, although such a strategy wouldn’t suffice for the municipalities north of New York City that rely on the Croton system. Reducing the local use of road salt seems to be the most practical approach. Implementing changes could involve encouraging state and local authorities to adopt salt alternatives, using sensors on plows to monitor road temperatures, or disabling salt applicators during maneuvers.
State Senator Pete Harckham, representing the affected region, referred to the report as alarming yet expected, recounting instances where high chloride levels had already led to the shutdown of several community wells. Harckham is advocating for legislation addressing the issue of road salt, including studying its impact on the Croton watershed. “It’s imperative for state agencies, local governments, everyone to collaborate on this,” he insisted, acknowledging the severity of the challenge.