This section contains minimum design and performance standards to control
erosion, maintain groundwater recharge, and control stormwater runoff quantity
impacts of major development projects.
A. The minimum design and performance standards for erosion
control are those established under the Soil Erosion and Sediment Control
Act, N.J.S.A. 4:24-39 et seq., and implementing rules.
B. The minimum design and performance standards for groundwater
recharge are as follows:
(1) Using the criteria for calculating stormwater runoff and groundwater recharge in §
296-17, the design engineer shall comply with at least one of the following standards:
(a) Demonstrate through hydrologic and hydraulic analysis
that the post-developed project site maintains 100% of the site's pre-developed
average annual groundwater recharge volume; or
(b) Demonstrate through hydrologic and hydraulic analysis
that any increase in the project site's projected stormwater runoff volume
produced by the two-year, twenty-four-hour storm from pre-developed to post-developed
conditions is fully infiltrated.
(2) Groundwater recharge is not required at major development projects located within an urban redevelopment area as defined in §
296-2 or from those portions of major development projects that produce stormwater runoff described in Subsection
B(3)(a)[3] below.
(3) The following two types of stormwater runoff shall not
be recharged:
(a) Stormwater runoff from areas of high pollutant loading.
High pollutant loading areas are:
[1] Areas in industrial and commercial developments where
solvents and/or petroleum products are loaded/unloaded, stored, or applied;
[2] Areas where pesticides are loaded/unloaded or stored;
[3] Areas where hazardous materials are expected to be present
in greater than "reportable quantities" as defined by the United States Environmental
Protection Agency (EPA) at 40 CFR 302.4; and
[4] Areas where recharge would be inconsistent with a Department-approved
remedial action work plan or landfill closure plan and areas with high risks
for spills of toxic materials, such as gas stations and vehicle maintenance
facilities; and
(b) Stormwater runoff from industrial areas exposed to source
material.
(4) The design engineer shall assess and certify the hydraulic
impact on the groundwater table and design the project site and all site groundwater
recharge measures so as to avoid adverse hydraulic impacts. Adverse hydraulic
impacts include, but are not limited to, raising the groundwater table so
as to cause surface ponding, flooding of basements and other subsurface facilities,
and interference with the proper operation of subsurface sewage disposal systems
and other subsurface structures in the vicinity of a groundwater recharge
measure.
C. The minimum design and performance standards for the
control of stormwater runoff quantity are as follows:
(1) Using the criteria for calculating stormwater runoff and groundwater recharge in Article
IV, the design engineer shall comply with at least one of the following standards:
(a) Demonstrate through hydrologic and hydraulic analysis
that the post-developed stormwater runoff hydrographs from the project site
for the two- , ten- and one-hundred-year storms do not exceed, at any point
in time, the site's pre-developed runoff hydrographs for the same storms;
(b) Demonstrate through hydrologic and hydraulic analysis
that under post-developed site conditions:
[1] There is no increase in pre-developed stormwater runoff
rates from the project site for the two- , ten- and one-hundred-year storms;
and
[2] Any increased stormwater runoff volume or change in stormwater
runoff timing for these storms will not increase flood damage at or downstream
of the project site. When performing this analysis for pre-developed site
conditions, all off-site development levels shall reflect existing conditions.
When performing this analysis for post-developed site conditions, all off-site
development levels shall reflect full development in accordance with current
zoning and land use ordinances.
(c) Design on-site stormwater management measures so that
the peak post-developed stormwater runoff rates from the project site for
the two- , ten- and one-hundred-year storms are 50%, 75% and 80%, respectively,
of the site's peak pre-developed stormwater runoff rates. Peak stormwater
outflow rates for these storms shall be adjusted where necessary to account
for the discharge of increased stormwater runoff rates and/or volumes from
project site areas not controlled by the on-site measures. The percentages
do not have to be applied to those portions of the project site that are not
proposed for development at the time of application, provided that such areas
are:
[1] Protected from future development by conservation easement,
deed restriction, or other acceptable legal measures; or
[2] Would be subject to review under these standards if they
are proposed for any degree of development in the future.
(2) Any application for a new agricultural or horticultural development that meets the definition of major development in §
296-6 shall be submitted to the appropriate Soil Conservation District for review and approval in accordance with the requirements of this section and any applicable Soil Conservation District guidelines for stormwater runoff quantity and erosion control.
The development shall incorporate a maintenance plan for the stormwater management measures incorporated into the design of a major development in accordance with Article
X.
The following linear development projects are exempt from the groundwater recharge, stormwater runoff quantity, and stormwater runoff quality requirements of §§
296-10 and
296-11:
A. The construction of an underground utility line provided,
that the disturbed areas are revegetated upon completion;
B. The construction of an aboveground utility line, provided
that the existing conditions are maintained to the maximum extent practicable;
and
C. The construction of a public pedestrian access, such as a sidewalk or trail with a maximum width of 14 feet, provided that the access is constructed of permeable material such as wood chips, unpacked gravel, and porous pavement. (See Article
VII for guidance.)
When habitat for threatened and endangered species (See definition for "environmental critical areas" in §
296-6.), is present on a site, stormwater management measures shall be implemented to avoid adverse impacts caused by pollutant discharge, the creation of concentrated flow, or the alteration of recharge.