August 20 Storm: NHSA Systems Move More Than 36 Million Gallons
The North Hudson Sewerage Authority (NHSA) responded to a significant storm event on August 21 that brought extremely heavy rainfall and widespread flooding throughout the service area.
The storm produced a peak 15-minute rainfall intensity of 2.68 inches per hour, with approximately 2.71 inches of total rainfall recorded across the service area. The rainfall occurred shortly after high tide, creating challenging drainage conditions and contributing to flooding in multiple communities.
To put that intensity in perspective, three inches per hour is a tropical downpour rate, roughly three times heavier than a typical summer thunderstorm. At that pace, about a half inch of rain can fall in just ten minutes, faster than streets and storm drains can carry it away. That is how a short, intense burst like this can flood streets even when the total rainfall for the day is modest.
Despite the severity of the storm, NHSA's pumping infrastructure operated continuously to move stormwater and reduce flood impacts where possible. During these conditions, our stormwater systems operated as designed.
Pump Station Performance
During the event:
The Northwest Resiliency Park pump system operated for approximately 4 hours, pumping an estimated 2.5 million gallons of water from the H6/H7 drainage area.
The H1 Pump Station operated for approximately 4 hours, pumping an estimated 8.7 million gallons.
The H5 Pump Station operated for approximately 12 hours, pumping an estimated 25 million gallons.
In total, NHSA facilities pumped approximately 36.2 million gallons of water during and after the storm event.
Supporting Community Resilience
Storms producing intense rainfall over short periods can overwhelm drainage systems, particularly when they occur near high tide. NHSA's pump stations and flood mitigation infrastructure are designed to help manage these conditions and reduce flooding impacts on residents, businesses, and public infrastructure.
NHSA continues to monitor system performance and invest in resiliency projects that strengthen the region's ability to respond to increasingly intense weather events.
Residents are encouraged to remain aware of local weather forecasts and follow guidance from municipal emergency management officials during severe storm events.
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