The proposed rule would update New Jersey’s existing flood hazard and stormwater regulations by replacing outdated precipitation estimates with modern data that accounts for observed and projected increases in rainfall. These changes would help to reduce flooding from stormwater runoff and increase the elevation of habitable first floors by two feet in certain new developments located in flood-prone inland areas.
“In order to ensure the safety and economic wellbeing of New Jerseyans both today and in the future, our policy decisions must be informed not by obsolete data, but by the challenging realities currently facing residents and businesses across the state,” said Governor Murphy. “Today New Jersey moves one step closer to further expanding the already extensive arsenal of climate adaptation measures at its disposal. Indeed, the inland flood protection rule is but one critical piece of our comprehensive and tireless efforts to safeguard vulnerable communities from physical harm and property damage, efforts that will produce a stronger and more resilient New Jersey for generations to come.”
“Updating the data New Jersey uses to manage stormwater runoff and determine building elevations along rivers and streams will help flood-prone communities to better protect their homes and businesses, making us more resilient to the increasing extreme weather that New Jersey is experiencing,” said Commissioner LaTourette. “My DEP colleagues and I are grateful for Governor Murphy’s vision and leadership in confronting the reality of New Jersey’s changing climate. And we deeply appreciate the thoughtful feedback we have received over the last two years of engagement with the public and leaders in labor, business, local government, academia, and advocacy while designing this and other important reforms as part of the New Jersey Protecting Against Climate Threats (NJ PACT) initiative.”
The rule proposal follows a series of informal public engagement sessions and sessions with stakeholders, including developers and labor organizations, environmental organizations, legislators, and municipal and county officials. It is anticipated that a formal rule proposal will be published in the New Jersey Register on December 5, 2022. Thereafter, a 60-day public comment period will run through February 3, 2023. A virtual public hearing will be held at 1 p.m. on January 11, 2023. A courtesy copy of the rule proposal can be found at https://dep.nj.gov/inland-flood-protection-rule/
Recent studies commissioned by the Murphy Administration regarding increased intensity of current and projected rainfall events indicate that additional resilience actions must be taken to better protect New Jersey’s people, communities, and public and private assets.
Rainfall runs off surfaces, into stormwater systems, and eventually into rivers and streams. Floodplains adjacent to these waterbodies accept overflow of these areas during flood events. While many floodplains are mapped by the Federal Emergency Management Agency (FEMA) and state government, existing flood maps are based on past conditions and do not account for changing conditions, such as increasing precipitation intensity. In some cases, flood mapping may not even be available in areas that now routinely flood.
To better protect public safety and property, the Inland Flood Protection Rule would establish design elevations that are reflective of New Jersey’s changing climate and the more frequent and intense rainfall we are experiencing. The updated standards would apply to certain new and substantially reconstructed development in inland riverine areas that are subject to flooding, but they do not prohibit development in these flood hazard areas. Under the two primary components of the rule:
- The elevation of habitable first floors would be two feet higher than currently indicated on DEP state flood maps and three feet higher than indicated on FEMA maps.
- Applicants for certain permits would use DEP’s New Jersey-specific precipitation data when calculating peak flow rates of streams and rivers for permits under the Flood Hazard Area Control Act Rules, N.J.A.C. 7:13, as well as when proposed development triggers compliance with DEP’s Stormwater Management rules, N.J.A.C. 7:8.
If adopted, the updated standards would apply to new or reconstructed development and not to existing development. Pending development applications before the DEP that are administratively complete at the time of a future adoption would not be affected by these changes. Existing provisions of the flood hazard and stormwater rules that provide flexibility from strict compliance based on unique site-specific conditions would remain in place, along with newly proposed provisions designed to ensure that infrastructure projects already in progress will continue to move forward.
In an effort to close severe climate data gaps and provide a reliable scientific basis for regulatory adjustments, the DEP commissioned New Jersey-specific studies that confirmed precipitation has increased in the state over the past 20 years and will continue to increase through the end of this century. The peer-reviewed studies, released in November 2021, were performed by the Northeast Regional Climate Center, a partner of the National Oceanic and Atmospheric Administration (NOAA).
Key findings showed that:
- Precipitation amounts that long guided state policy, planning and development criteria relied upon data obtained through 1999 and did not accurately reflect current precipitation intensity conditions. Extreme precipitation amounts are 1 percent to 15 percent higher now than the 1999 data suggests. Therefore, the 1999 data previously in use is outdated and not reflective of current precipitation.
- Precipitation during the 100-year storm is likely to increase by 23 percent to 50 percent above the 1999 baseline by 2100. These numbers represent the upper end of the likely range as defined by the Intergovernmental Panel on Climate Change (IPCC). Projected changes will be greater in the northern part of the state than in the southern and coastal areas.
In connection with the proposed Inland Flood Protection Rule, to aid the public to gauge flood risk and provide a visual approximation of regulatory jurisdiction on specific parcels, the DEP has launched a flood indicator tool. While the tool does not provide a definitive demonstration of regulatory jurisdiction or calculate actual risk, it can be useful in assisting property owners or prospective property owners on potential risk and, by referencing the 500-year flood extent, approximate DEP’s regulatory jurisdiction and flood risk. Armed with this information, property owners may then decide to take additional steps to determine actual risk, which is dependent on site-specific conditions.
Stormwater grant funding is available to help local officials understand and improve local stormwater management, thereby reducing flooding and improving water quality. The deadline to apply for the Stormwater Utility Technical Assistance Grant is November 1, 2022.