NJDEP has proposed major amendments to the Stormwater Management rules at N.J.A.C. 7:8. (50 N.J.R. 2375(a)).  One of those proposed amendments, if adopted, will prevent or severely limit a developer’s ability to incorporate non-structural stormwater management strategies such as stormwater detention basins in a development. Instead, the developer will be required to utilize “green infrastructure” best management practices (“BMPs”).  One of the best definitions of green infrastructure comes from American Rivers:  “Green infrastructure is an approach to water management that protects, restores, or mimics the natural water cycle.”

The stated rationale for the amendments are that stormwater detention basins that collect surface water runoff from development-wide drainage areas, particularly runoff from paved or developed surfaces that prevent or limit rainfall infiltration, do not “mimic” the natural water cycle.  Nor are they as efficient at removing total suspended solids as smaller scale green infrastructure BMPs.

The proposed rule intends to replace non-structural strategies with green infrastructure that meets standards for groundwater recharge, stormwater quantity and stormwater runoff quality.  Table 5-1 of the proposed regulation lists such Green Infrastructure BMPs which include cisterns, dry wells, grass swales, green roofs, manufactured treatment devices, pervious paving systems, small-scale bioretention systems, small-scale infiltration basins, small-scale sand filters and vegetative filter strips.  The proposed rules do provide for waivers from strict compliance under specified circumstances.

There is a sixty day comment period and many comments are expected.  This proposal is a major change to existing practices and likely will increase development costs and result in the loss of developable land in any major development project.