Assessing Combined Sewer Systems Vulnerability to Sea Level Rise

Sea level in the Harbor Estuary is expected to rise between 0.9 and 2.1 feet by 2050, with a worst-case projection of up to 6 feet by 2100. The functioning of combined sewer systems will be directly affected, as many outfalls are already underwater during high tides. This looming issue will compound the existing challenge of reducing the number and volume of discharges from combined sewers, which occur when sewage treatment plants reach capacity during storms, a pollution source that will increase in the future given anticipated changes in precipitation.

In New Jersey, the 17 municipalities and 4 utilities with active Combined Sewer Overflow (CSO) permits for estuary waters are addressing their Long-Term Control Plan (LTCP) requirements. The current requirements do not explicitly require permittees to address impacts associated with climate change. To understand the magnitude of these issues and better prepare for the future, HEP partnered with two New Jersey municipalities, the City of Elizabeth and the Village of Ridgefield Park, to assess the risk of sea level rise impacts to their respective CSO outfalls.

HEP worked with both municipalities and the EPA using EPA’s Climate Resilience Evaluation and Awareness Tool (CREAT). CREAT is a risk assessment application that helps municipalities and utilities adapt to extreme weather events by better understanding current and long-term weather conditions. The final report and recorded webinars below provides important examples and guidance for managers and engineering professionals seeking to create climate-ready water systems.

Webinars and Reports

Related Resources

Water and Wastewater Utilities Planning for Resilience

Elizabeth and Ridgefield Park’s use of CREAT and how they were able to evaluate the costs of several potential management strategies.

CREAT Risk Assessment Application for Water Utilities

EPA’s CREAT is a risk assessment application or tool that helps utilities to better understanding current and long-term weather conditions.

NJ’s Rising Seas and Changing Coastal Storms

The report, published in 2019 by Rutgers University, highlights the most recent climate science needed to inform efforts to increase the resilience in NJ.

NJ Flood Mapper

Developed by Rutgers University, this interactive mapping website helps generate map visuals regrading flooding hazards and sea level rise in the state of NJ.

Hudson River Foundation