Green Infrastructure is now a requirement. What do municipalities need to know about NJ’s amended stormwater rules?
The New Jersey Department of Environmental Protection (NJDEP) has published a revised set of stormwater regulations that will affect land development practices within the state. The revisions require the use of decentralized green infrastructure practices and provide a more objective review process for projects. The new rule amendments take effect March 2, 2021.
Previous regulations required the use of nonstructural stormwater management strategies to “the maximum extent practicable.” The new rules eliminate this subjective language and instead provide a clearly articulated, mathematically-based set of standards for stormwater design compliance.
A second, but equally important, component to the new rule is the change in permitted stormwater modeling criteria. Infiltration of captured stormwater through best management practices (BMPs) is now permitted in engineering calculations. This change will result in smaller stormwater BMPs, thus maximizing developable area on a site.
Beyond the use of green infrastructure and the impact of receiving credit for stormwater infiltration, the rules introduce additional changes that will impact development. Guidance is provided on both small and large scale BMPs. New tables clarify the applicability of different BMPs when used to meet the requirements for groundwater recharge, water quality, and quantity standards. Additional engineering calculation methods relevant to green stormwater infrastructure design are also incorporated.
In order to assist design professionals in selecting the right BMPs to meet these standards, the new rule separates BMPs into three (3) tables:
Every NJ municipality must update its stormwater ordinance to reflect and comply with the new rule language. NJDEP provides a sample stormwater ordinance.
Local stormwater ordinances may impose stricter requirements than are found in the new state stormwater rule for certain kinds of projects. In the preamble to its new model stormwater ordinance, NJDEP specifies how. For example, municipalities may choose to define “major development” with a smaller area of disturbance and/or smaller area of regulated impervious cover or regulated motor vehicle surface; apply stormwater requirements to both major and minor development; and/or require groundwater recharge, when feasible, in urban redevelopment areas. See our Update and Improve Ordinances section for more.
Note: these kinds of higher standards can be applied only to nonresidential projects that go before the local planning board or zoning board of adjustment. Residential projects are governed by the Residential Site Improvement Standards (RSIS), which reference the current stormwater rule. Thus, residential projects subject to planning board or zoning board review must meet the state’s minimum standards, no more and no less.
Proper training is important to ensure that successful green infrastructure is installed in your municipality. The following groups will benefit from training:
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Gabriel Mahon, Chief, Bureau of Nonpoint Pollution Control Division of Water Quality, NJDEP
The Guide breaks down New Jersey’s Stormwater Rule amendments and helps developers and decision-makers understand green infrastructure options (even for challenging sites), advantages, costs, and benefits.
On March 2, important changes to the state’s stormwater management rules (NJAC 7:8) were published in the New Jersey Register.
Access the amended rules.
These amendments to the stormwater rules have been in the works for years. They include a requirement that green infrastructure must be used to meet stormwater management standards for water quality, groundwater recharge and quantity control.