Green Infrastructure implementation and Municipal Watershed Planning are now required. What do municipalities need to know about NJ’s stormwater rules and the new MS4 Permit?
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 took 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:
NJDEP’s Stormwater Management (SWM) rules at N.J.A.C 7:8 will be updated through the New Jersey Protecting Against Climate Threat (NJ PACT) land use regulatory reform. The updates will be based on updated precipitation data and projections based on the latest climate science. These updates will require stormwater Best Management Practices (BMPs) to manage both current and future storms. The Inland Flood Protection Rule (IFP) is the first phase of this reform and will be followed by NJ Resilient Environments and Landscapes (REAL). Check back for more information when the updated rules are effective.
Every NJ municipality must update its stormwater ordinance to comply with new amendments to the Stormwater Management Rules (NJAC 7:8). NJDEP provides a sample stormwater ordinance. New Jersey Future’s Enhanced Model Stormwater Ordinance, also available as an editable Word document, provides several options for municipalities to strengthen their ordinances to increase green infrastructure and reduce flood risk.
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.
Upgrading and retrofitting New Jersey’s stormwater infrastructure and reducing impervious cover is a key way to address nonpoint source pollution. Stormwater Best Management Practices (BMPs), including green infrastructure, are an integral part of both improving the quality of New Jersey’s lakes, rivers, streams, and bays and reducing dangerous flooding events worsened by climate change.
The new Tier A Municipal Separate Storm Sewer System (MS4) permit, effective January 1, 2023, reflects a shift toward watershed level planning to address water quality issues and flooding in order to better protect communities from the impacts of climate change. A significant change from the previous permit is the inclusion of the Watershed Improvement Plan (WIP) requirement, which is aimed to address nonpoint source pollution and identify water quality improvement projects.
New Jersey Future and One Water Consulting, LLC created an MS4 Primer to help municipalities understand the recent changes to the MS4 Permit and address stormwater issues related to new and existing development. The MS4 Permit and this Primer provide a framework for water quality improvements and a regional approach to stormwater management in New Jersey.
Check out New Jersey Future’s MS4 Fact Sheet for an overview of changes from the 2018 Tier A MS4 Permit.
All towns previously considered Tier B, over 100 municipalities, have been reclassified as Tier A. This reclassification means all of New Jersey’s municipalities are subject to permitting obligations informed by federal regulations, which include more stringent requirements set forth in the Clean Water Act. -Check back here for future updates and resources.
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
See pages 14-19 of the document for the checklist, which helps municipalities to conduct stormwater management reviews.
It’s Official: NJDEP Amends State Stormwater Rules to Require Green Infrastructure (Mar. 2020)
New NJDEP Watershed Improvement Plan Requirement and What This Means for Municipalities (January 2023)
Want to Get Ahead of Flooding? Use NJF’s New Tool, the Enhanced Model Stormwater Ordinance (February 2021)
New Stormwater Rules Require New Developments to Include Green Infrastructure (March 2021)
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.