[Added 3-9-2021 by Ord.
No. 02-2021]
A. This article shall be known and referred to as the "Stormwater Control
Ordinance of the Borough of Franklin, Sussex County, New Jersey."
B. Flood control, groundwater recharge, and pollutant reduction shall
be achieved through the use of stormwater management measures, including
green infrastructure best management practices (GI BMPs) and nonstructural
stormwater management strategies. GI BMPs and low-impact development
(LID) should be utilized to meet the goal of maintaining natural hydrology
to reduce stormwater runoff volume, reduce erosion, encourage infiltration
and groundwater recharge, and reduce pollution. GI BMPs and LID should
be developed based upon physical site conditions and the origin, nature
and the anticipated quantity, or amount, of potential pollutants.
Multiple stormwater management BMPs may be necessary to achieve the
established performance standards for water quality, quantity, and
groundwater recharge.
C. The purpose of this article is to establish minimum stormwater management
requirements and controls for "major development," as defined below.
D. This article shall be applicable to the following major developments:
(1) Nonresidential major developments;
(2) Aspects of residential major developments that are not preempted
by the Residential Site Improvement Standards at N.J.A.C. 5:21; and
(3) All major developments undertaken by the Borough of Franklin.
E. Development approvals issued pursuant to this article are to be considered
an integral part of development approvals and do not relieve the applicant
of the responsibility to secure required permits or approvals for
activities regulated by any other applicable code, rule, act, or ordinance.
In their interpretation and application, the provisions of this article
shall be held to be the minimum requirements for the promotion of
the public health, safety, and general welfare. This article is not
intended to interfere with, abrogate, or annul any other ordinances,
rule or regulation, statute, or other provision of law except that,
where any provision of this article imposes restrictions different
from those imposed by any other ordinance, rule or regulation, or
other provision of law, the more restrictive provisions or higher
standards shall control.
F. For the purpose of this article, the following terms, phrases, words
and their derivations shall have the meanings based on the corresponding
definitions in the Stormwater Management Rules at N.J.A.C. 7:8-1.2.
[Added 3-9-2021 by Ord.
No. 02-2021]
[Added 3-9-2021 by Ord.
No. 02-2021]
A. Stormwater management measures for major development shall be designed
to provide erosion control, groundwater recharge, stormwater runoff
quantity control, and stormwater runoff quality treatment as follows:
(1)
The minimum standards for erosion control are those established
under the Soil and Sediment Control Act, N.J.S.A. 4:24-39 et seq.,
and implementing rules at N.J.A.C. 2:90.
(2)
The minimum standards for groundwater recharge, stormwater quality,
and stormwater runoff quantity shall be met by incorporating green
infrastructure.
B. The standards in this article apply only to new major development
and are intended to minimize the impact of stormwater runoff on water
quality and water quantity in receiving water bodies and maintain
groundwater recharge.
[Added 3-9-2021 by Ord.
No. 02-2021]
A. The development shall incorporate a maintenance plan for the stormwater management measures incorporated into the design of a major development in accordance with §
161-48.
B. Stormwater management measures shall avoid adverse impacts of concentrated
flow on habitat for threatened and endangered species as documented
in the Department's Landscape Project or Natural Heritage Database
established under N.J.S.A. 13:1B-15.147 through 13:1B-15.150, particularly
Helonias bullata (swamp pink) and/or Clemmys muhlenbergii (bog turtle).
C. The following linear development projects are exempt from the groundwater recharge, stormwater runoff quality, and stormwater runoff quantity requirements of §§
161-46.4,
161-46.5, and
161-46.6:
(1)
The construction of an underground utility line, provided that
the disturbed areas are revegetated upon completion;
(2)
The construction of an aboveground utility line, provided that
the existing conditions are maintained to the maximum extent practicable;
and
(3)
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 made of permeable material.
D. A waiver from strict compliance from the green infrastructure, groundwater recharge, stormwater runoff quality, and stormwater runoff quantity requirements of §§
161-46.3,
161-46.4,
161-46.5, and
161-46.6 may be obtained for the enlargement of an existing public roadway or railroad; or the construction or enlargement of a public pedestrian access, provided that the following conditions are met:
(1)
The applicant demonstrates that there is a public need for the
project that cannot be accomplished by any other means;
(2)
The applicant demonstrates through an alternatives analysis, that through the use of stormwater management measures, the option selected complies with the requirements of §§
161-46.3,
161-46.4,
161-46.5, and
161-46.6 to the maximum extent practicable;
(3)
The applicant demonstrates that, in order to meet the requirements of §§
161-46.3,
161-46.4,
161-46.5, and
161-46.6, existing structures currently in use, such as homes and buildings, would need to be condemned; and
(4)
The applicant demonstrates that it does not own or have other rights to areas, including the potential to obtain through condemnation lands not falling under Subsection
D(3) above within the upstream drainage area of the receiving stream, that would provide additional opportunities to mitigate the requirements of §§
161-46.3,
161-46.4,
161-46.5, and
161-46.6 that were not achievable on-site.
E. Tables 5-1, 5-2 and 5-3 in N.J.A.C. 7:8-5.2(f) summarize the ability of stormwater best management practices identified and described in the New Jersey Stormwater Best Management Practices Manual to satisfy the green infrastructure, groundwater recharge, stormwater runoff quality and stormwater runoff quantity standards specified in §§
161-46.3,
161-46.4,
161-46.5, and
161-46.6. When designed in accordance with the most current version of the New Jersey Stormwater Best Management Practices Manual, the stormwater management measures found at N.J.A.C. 7:8-5.2(f), Tables 5-1, 5-2 and 5-3, are presumed to be capable of providing stormwater controls for the design and performance standards. Upon amendments of the New Jersey stormwater best management practices to reflect additions or deletions of BMPs meeting these standards, or changes in the presumed performance of BMPs designed in accordance with the New Jersey Stormwater BMP Manual, the Department shall publish in the New Jersey Registers a notice of administrative change revising the applicable table. The most current version of the BMP Manual can be found on the Department's website at https://njstormwater.org/bmp_manual2.htm.
F. Where the BMP tables in the NJ Stormwater Management Rule are different
due to updates or amendments, the BMP Tables in the Stormwater Management
Rule at N.J.A.C. 7:8-5.2(f) shall take precedence.
G. An alternative stormwater management measure, alternative removal rate, and/or alternative method to calculate the removal rate may be used if the design engineer demonstrates the capability of the proposed alternative stormwater management measure and/or the validity of the alternative rate or method to the municipality. A copy of any approved alternative stormwater management measure, alternative removal rate, and/or alternative method to calculate the removal rate shall be provided to the Department in accordance with §
161-46.9B. Alternative stormwater management measures may be used to satisfy the requirements at §
161-46.3 only if the measures meet the definition of "green infrastructure" at §
161-45. Alternative stormwater management measures that function in a similar manner to a BMP listed at §
161-46.3A are subject to the contributory drainage area limitation specified at §
161-46.3A for that similarly functioning BMP. Alternative stormwater management measures approved in accordance with this section that do not function in a similar manner to any BMP listed at §
161-46.3A shall have a contributory drainage area less than or equal to 2.5 acres, except for alternative stormwater management measures that function similarly to cisterns, grass swales, green roofs, standard constructed wetlands, vegetative filter strips, and wet ponds, which are not subject to a contributory drainage area limitation. Alternative measures that function similarly to standard constructed wetlands or wet ponds shall not be used for compliance with the stormwater runoff quality standard unless a variance in accordance with N.J.A.C. 7:8-4.6 or a waiver from strict compliance in accordance with §
161-46.2D is granted from §
161-46.3.
H. Whenever the stormwater management design includes one or more BMPs
that will infiltrate stormwater into subsoil, the design engineer
shall assess the hydraulic impact on the groundwater table and design
the site, so as to avoid adverse hydraulic impacts. Potential adverse
hydraulic impacts include, but are not limited to, exacerbating a
naturally or seasonally high-water table, so as to cause surficial
ponding, flooding of basements, or interference with the proper operation
of subsurface sewage disposal systems or other subsurface structures
within the zone of influence of the groundwater mound, or interference
with the proper functioning of the stormwater management measure itself.
I. Design standards for stormwater management measures are as follows:
(1)
Stormwater management measures shall be designed to take into
account the existing site conditions, including, but not limited to,
environmentally critical areas; wetlands; flood-prone areas; slopes;
depth to seasonal high-water table; soil type, permeability, and texture;
drainage area and drainage patterns; and the presence of solution-prone
carbonate rocks (limestone);
(2)
Stormwater management measures shall be designed to minimize maintenance, facilitate maintenance and repairs, and ensure proper functioning. Trash racks shall be installed at the intake to the outlet structure, as appropriate, and shall have parallel bars with one-inch spacing between the bars to the elevation of the water quality design storm. For elevations higher than the water quality design storm, the parallel bars at the outlet structure shall be spaced no greater than 1/3 the width of the diameter of the orifice or 1/3 the width of the weir, with a minimum spacing between bars of one inch and a maximum spacing between bars of six inches. In addition, the design of trash racks must comply with the requirements of §
161-46.10;
(3)
Stormwater management measures shall be designed, constructed,
and installed to be strong, durable, and corrosion resistant. Measures
that are consistent with the relevant portions of the Residential
Site Improvement Standards at N.J.A.C. 5:21-7.3, 5:21-7.4, and 5:21-7.5
shall be deemed to meet this requirement;
(4)
Stormwater management BMPs shall be designed to meet the minimum safety standards for stormwater management BMPs at §
161-46.10; and
(5)
The size of the orifice at the intake to the outlet from the
stormwater management BMP shall be a minimum of 2 1/2 inches
in diameter.
J. Manufactured treatment devices may be used to meet the requirements of this section, provided the pollutant removal rates are verified by the New Jersey Corporation for Advanced Technology and certified by the Department. Manufactured treatment devices that do not meet the definition of "green infrastructure" at §
161-45F may be used only under the circumstances described at §
161-46.3C.
K. Any application for a new agricultural development that meets the definition of "major development" at §
161-45F shall be submitted to the Soil Conservation District for review and approval in accordance with the requirements at §§
161-46.3,
161-46.4,
161-46.5, and
161-46.6 and any applicable Soil Conservation District guidelines for stormwater runoff quantity and erosion control. For purposes of this section, "agricultural development" means land uses normally associated with the production of food, fiber, and livestock for sale. Such uses do not include the development of land for the processing or sale of food and the manufacture of agriculturally related products.
L. If there is more than one drainage area, the groundwater recharge, stormwater runoff quality, and stormwater runoff quantity standards at §§
161-46.4,
161-46.5, and
161-46.6 shall be met in each drainage area, unless the runoff from the drainage areas converge on-site and no adverse environmental impact would occur as a result of compliance with any one or more of the individual standards being determined utilizing a weighted average of the results achieved for that individual standard across the affected drainage areas.
M. Any stormwater management measure authorized under the municipal stormwater management plan or ordinance shall be reflected in a deed notice recorded in the Sussex County Clerk's office. A form of deed notice shall be submitted to the municipality for approval prior to filing. The deed notice shall contain a description of the stormwater management measure(s) used to meet the green infrastructure, groundwater recharge, stormwater runoff quality, and stormwater runoff quantity standards at §§
161-46.3 161-46.4, 161-46.5, and 161-46.6 and shall identify the location of the stormwater management measure(s) in NAD 1983 State Plane New Jersey FIPS 2900 US feet or latitude and longitude in decimal degrees. The deed notice shall also reference the maintenance plan required to be recorded upon the deed pursuant to § 161-48B.(5). Prior to the commencement of construction, proof that the above required deed notice has been filed shall be submitted to the municipality. Proof that the required information has been recorded on the deed shall be in the form of either a copy of the complete recorded document or a receipt from the Clerk or other proof of recordation provided by the recording office. However, if the initial proof provided to the municipality is not a copy of the complete recorded document, a copy of the complete recorded document shall be provided to the municipality within 180 calendar days of the authorization granted by the municipality.
N. A stormwater management measure approved under the municipal stormwater management plan or ordinance may be altered or replaced with the approval of the municipality, if the municipality determines that the proposed alteration or replacement meets the design and performance standards pursuant to §§
161-46.2 through
161-46.6 of this article and provides the same level of stormwater management as the previously approved stormwater management measure that is being altered or replaced. If an alteration or replacement is approved, a revised deed notice shall be submitted to the municipality for approval and subsequently recorded with the Sussex County Clerk's office and shall contain a description and location of the stormwater management measure, as well as reference to the maintenance plan, in accordance with Subsection
M above. Prior to the commencement of construction, proof that the above required deed notice has been filed shall be submitted to the municipality in accordance with Subsection
M above.
[Added 3-9-2021 by Ord.
No. 02-2021]
This section specifies the types of green infrastructure BMPs
that may be used to satisfy the groundwater recharge, stormwater runoff
quality, and stormwater runoff quantity standards.
A. To satisfy the groundwater recharge and stormwater runoff quality standards at §§
161-46.4 and
161-46.5, the design engineer shall utilize green infrastructure BMPs identified in §
161-46.2F and/or an alternative stormwater management measure approved in accordance with §
161-46.2G. The following green infrastructure BMPs are subject to the following maximum contributory drainage area limitations:
Best Management Practice
|
Maximum Contributory Drainage Area
(acres)
|
---|
Dry well
|
1
|
Manufactured treatment device
|
2.5
|
Pervious pavement systems
|
Area of additional inflow cannot exceed 3 times the area occupied
by the BMP
|
Small-scale bioretention systems
|
2.5
|
Small-scale infiltration basin
|
2.5
|
Small-scale sand filter
|
2.5
|
B. To satisfy the stormwater runoff quantity standards at §
161-46.6, the design engineer shall utilize BMPs and/or an alternative stormwater management measure approved in accordance with §
161-46.2G.
C. If a variance in accordance with N.J.A.C. 7:8-4.6 or a waiver from strict compliance in accordance with §
161-46.2D is granted from the requirements of this section, then BMPs and/or an alternative stormwater management measure approved in accordance with §
161-46.2G may be used to meet the groundwater recharge, stormwater runoff quality, and stormwater runoff quantity standards at §§
161-46.4,
161-46.5 and
161-46.6.
D. For separate or combined storm sewer improvement projects, such as sewer separation, undertaken by a government agency or public utility (for example, a sewerage company), the requirements of this section shall only apply to areas owned in fee simple by the government agency or utility, and areas within a right-of-way or easement held or controlled by the government agency or utility; the entity shall not be required to obtain additional property or property rights to fully satisfy the requirements of this section. Regardless of the amount of area of a separate or combined storm sewer improvement project subject to the green infrastructure requirements of this section, each project shall fully comply with the applicable groundwater recharge, stormwater runoff quality control, and stormwater runoff quantity standards at §§
161-46.4,
161-46.5 and
161-46.6, unless the project is granted a waiver from strict compliance in accordance with §
161-46.2D.
[Added 3-9-2021 by Ord.
No. 02-2021]
This section contains the minimum design and performance standards
for groundwater recharge as follows:
A. The design engineer shall, using the assumptions and factors for stormwater runoff and groundwater recharge calculations at §
161-46.7, either:
(1)
Demonstrate through hydrologic and hydraulic analysis that the
site and its stormwater management measures maintain 100% of the average
annual preconstruction groundwater recharge volume for the site; or
(2)
Demonstrate through hydrologic and hydraulic analysis that the
increase of stormwater runoff volume from preconstruction to post-construction
for the two-year storm is infiltrated.
B. This groundwater recharge requirement does not apply to projects within the urban redevelopment area, or to projects subject to Subsection
C below.
C. The following types of stormwater shall not be recharged:
(1)
Stormwater from areas of high pollutant loading. High pollutant
loading areas are areas in industrial and commercial developments
where solvents and/or petroleum products are loaded/unloaded, stored,
or applied, areas where pesticides are loaded/unloaded or stored;
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; areas where recharge would
be inconsistent with 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
(2)
Industrial stormwater exposed to source material. "Source material"
means any material(s) or machinery, located at an industrial facility,
that is directly or indirectly related to process, manufacturing or
other industrial activities, which could be a source of pollutants
in any industrial stormwater discharge to groundwater. Source materials
include, but are not limited to, raw materials; intermediate products;
final products; waste materials; by-products; industrial machinery
and fuels, and lubricants, solvents, and detergents that are related
to process, manufacturing, or other industrial activities that are
exposed to stormwater.
[Added 3-9-2021 by Ord.
No. 02-2021]
This section contains the minimum design and performance standards
to control stormwater runoff quality impacts of major development.
Stormwater runoff quality standards are applicable when the major
development results in an increase of 1/4 acre or more of regulated
motor vehicle surface.
A. Stormwater management measures shall be designed to reduce the post-construction
load of total suspended solids (TSS) in stormwater runoff generated
from the water quality design storm as follows:
(1)
Eighty percent TSS removal of the anticipated load, expressed
as an annual average shall be achieved for the stormwater runoff from
the net increase of motor vehicle surface.
(2)
If the surface is considered regulated motor vehicle surface
because the water quality treatment for an area of motor vehicle surface
that is currently receiving water quality treatment either by vegetation
or soil, by an existing stormwater management measure, or by treatment
at a wastewater treatment plant is to be modified or removed, the
project shall maintain or increase the existing TSS removal of the
anticipated load expressed as an annual average.
B. The requirement to reduce TSS does not apply to any stormwater runoff in a discharge regulated under a numeric effluent limitation for TSS imposed under the New Jersey Pollutant Discharge Elimination System (NJPDES) rules, N.J.A.C. 7:14A, or in a discharge specifically exempt under a NJPDES permit from this requirement. Every major development, including any that discharge into a combined sewer system, shall comply with Subsection
A above, unless the major development is itself subject to a NJPDES permit with a numeric effluent limitation for TSS or the NJPDES permit to which the major development is subject exempts the development from a numeric effluent limitation for TSS.
C. The water quality design storm is 1.25 inches of rainfall in two
hours. Water quality calculations shall take into account the distribution
of rain from the water quality design storm, as reflected in Table
1, below. The calculation of the volume of runoff may take into account
the implementation of stormwater management measures.
Table 1
|
---|
Water Quality Design Storm Distribution
|
---|
Time
(minutes)
|
Cumulative Rainfall
(inches)
|
Time
(minutes)
|
Cumulative Rainfall
(inches)
|
Time
(minutes)
|
Cumulative Rainfall
(inches)
|
---|
1
|
0.00166
|
41
|
0.1728
|
81
|
1.0906
|
2
|
0.00332
|
42
|
0.1796
|
82
|
1.0972
|
3
|
0.00498
|
43
|
0.1864
|
83
|
1.1038
|
4
|
0.00664
|
44
|
0.1932
|
84
|
1.1104
|
5
|
0.00830
|
45
|
0.2000
|
85
|
1.1170
|
6
|
0.00996
|
46
|
0.2117
|
86
|
1.1236
|
7
|
0.01162
|
47
|
0.2233
|
87
|
1.1302
|
8
|
0.01328
|
48
|
0.2350
|
88
|
1.1368
|
9
|
0.01494
|
49
|
0.2466
|
89
|
1.1434
|
10
|
0.01660
|
50
|
0.2583
|
90
|
1.1500
|
11
|
0.01828
|
51
|
0.2783
|
91
|
1.1550
|
12
|
0.01996
|
52
|
0.2983
|
92
|
1.1600
|
13
|
0.02164
|
53
|
0.3183
|
93
|
1.1650
|
14
|
0.02332
|
54
|
0.3383
|
94
|
1.1700
|
15
|
0.02500
|
55
|
0.3583
|
95
|
1.1750
|
16
|
0.03000
|
56
|
0.4116
|
96
|
1.1800
|
17
|
0.03500
|
57
|
0.4650
|
97
|
1.1850
|
18
|
0.04000
|
58
|
0.5183
|
98
|
1.1900
|
19
|
0.04500
|
59
|
0.5717
|
99
|
1.1950
|
20
|
0.05000
|
60
|
0.6250
|
100
|
1.2000
|
21
|
0.05500
|
61
|
0.6783
|
101
|
1.2050
|
22
|
0.06000
|
62
|
0.7317
|
102
|
1.2100
|
23
|
0.06500
|
63
|
0.7850
|
103
|
1.2150
|
24
|
0.07000
|
64
|
0.8384
|
104
|
1.2200
|
25
|
0.07500
|
65
|
0.8917
|
105
|
1.2250
|
26
|
0.08000
|
66
|
0.9117
|
106
|
1.2267
|
27
|
0.08500
|
67
|
0.9317
|
107
|
1.2284
|
28
|
0.09000
|
68
|
0.9517
|
108
|
1.2300
|
29
|
0.09500
|
69
|
0.9717
|
109
|
1.2317
|
30
|
0.10000
|
70
|
0.9917
|
110
|
1.2334
|
31
|
0.10660
|
71
|
1.0034
|
111
|
1.2351
|
32
|
0.11320
|
72
|
1.0150
|
112
|
1.2367
|
33
|
0.11980
|
73
|
1.0267
|
113
|
1.2384
|
34
|
0.12640
|
74
|
1.0383
|
114
|
1.2400
|
35
|
0.13300
|
75
|
1.0500
|
115
|
1.2417
|
36
|
0.13960
|
76
|
1.0568
|
116
|
1.2434
|
37
|
0.14620
|
77
|
1.0636
|
117
|
1.2450
|
38
|
0.15280
|
78
|
1.0704
|
118
|
1.2467
|
39
|
0.15940
|
79
|
1.0772
|
119
|
1.2483
|
40
|
0.16600
|
80
|
1.0840
|
120
|
1.2500
|
D. If more than one BMP in series is necessary to achieve the required
80% TSS reduction for a site, the applicant shall utilize the following
formula to calculate TSS reduction:
Where:
|
R
|
=
|
total TSS percent load removal from application of both BMPs.
|
A
|
=
|
the TSS percent removal rate applicable to the first BMP.
|
B
|
=
|
the TSS percent removal rate applicable to the second BMP.
|
E. Stormwater management measures shall also be designed to reduce, to the maximum extent feasible, the post-construction nutrient load of the anticipated load from the developed site in stormwater runoff generated from the water quality design storm. In achieving reduction of nutrients to the maximum extent feasible, the design of the site shall include green infrastructure BMPs that optimize nutrient removal while still achieving the performance standards in §§
161-46.4,
161-46.5 and
161-46.6.
F. In accordance with the definition of "FW1" at N.J.A.C. 7:9B-1.4,
stormwater management measures shall be designed to prevent any increase
in stormwater runoff to waters classified as "FW1."
G. The Flood Hazard Area Control Act Rules at N.J.A.C. 7:13-4.1(c)1
establish 300-foot riparian zones along Category One waters, as designated
in the Surface Water Quality Standards at N.J.A.C. 7:9B, and certain
upstream tributaries to Category One waters. A person shall not undertake
a major development that is located within or discharges into a 300-foot
riparian zone without prior authorization from the Department under
N.J.A.C. 7:13.
H. Pursuant to the Flood Hazard Area Control Act Rules at N.J.A.C. 7:13-11.2(j)3i,
runoff from the water quality design storm that is discharged within
a 300-foot riparian zone shall be treated in accordance with this
section to reduce the post-construction load of total suspended solids
by 95% of the anticipated load from the developed site, expressed
as an annual average.
I. This stormwater runoff quality standards do not apply to the construction
of one individual single-family dwelling, provided that it is not
part of a larger development or subdivision that has received preliminary
or final site plan approval prior to December 3, 2018, and that the
motor vehicle surfaces are made of permeable material(s), such as
gravel, dirt, and/or shells.
[Added 3-9-2021 by Ord.
No. 02-2021]
This section contains the minimum design and performance standards
to control stormwater runoff quantity impacts of major development.
A. In order to control stormwater runoff quantity impacts, the design engineer shall, using the assumptions and factors for stormwater runoff calculations at §
161-46.7, complete one of the following:
(1)
Demonstrate through hydrologic and hydraulic analysis that for
stormwater leaving the site, post-construction runoff hydrographs
for the two-, ten-, and 100-year storm events do not exceed, at any
point in time, the preconstruction runoff hydrographs for the same
storm events;
(2)
Demonstrate through hydrologic and hydraulic analysis that there
is no increase, as compared to the preconstruction condition, in the
peak runoff rates of stormwater leaving the site for the two-, ten-,
and 100-year storm events and that the increased volume or change
in timing of stormwater runoff will not increase flood damage at or
downstream of the site. This analysis shall include the analysis of
impacts of existing land uses and projected land uses assuming full
development under existing zoning and land use ordinances in the drainage
area;
(3)
Design stormwater management measures so that the post-construction
peak runoff rates for the two-, ten- and 100-year storm events are
50%, 75% and 80%, respectively, of the preconstruction peak runoff
rates. The percentages apply only to the post-construction stormwater
runoff that is attributable to the portion of the site on which the
proposed development or project is to be constructed; or
(4)
In tidal flood hazard areas, stormwater runoff quantity analysis in accordance with Subsection
A(1),
(2) and
(3) above is required unless the design engineer demonstrates through hydrologic and hydraulic analysis that the increased volume, change in timing, or increased rate of the stormwater runoff, or any combination of the three will not result in additional flood damage below the point of discharge of the major development. No analysis is required if the stormwater is discharged directly into any ocean, bay, inlet, or the reach of any watercourse between its confluence with an ocean, bay, or inlet and downstream of the first water control structure.
B. The stormwater runoff quantity standards shall be applied at the
site's boundary to each abutting lot, roadway, watercourse, or
receiving storm sewer system.
[Added 3-9-2021 by Ord.
No. 02-2021]
A. Stormwater runoff shall be calculated in accordance with the following:
(1)
The design engineer shall calculate runoff using one of the
following methods:
(a)
The USDA Natural Resources Conservation Service (NRCS) methodology,
including the NRCS Runoff Equation and Dimensionless Unit Hydrograph,
as described in Chapters 7, 9, 10, 15 and 16, Part 630, Hydrology
National Engineering Handbook, incorporated herein by reference as
amended and supplemented. This methodology is additionally described
in Technical Release 55 - Urban Hydrology for Small Watersheds (TR-55),
dated June 1986, incorporated herein by reference as amended and supplemented.
Information regarding the methodology is available from the Natural
Resources Conservation Service website at https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1044171.pdf
or at United States Department of Agriculture Natural Resources Conservation
Service, 220 Davison Avenue, Somerset, New Jersey 08873; or
(b)
The Rational Method for peak flow and the Modified Rational
Method for hydrograph computations. The Rational and Modified Rational
Methods are described in "Appendix A-9 Modified Rational Method" in
the Standards for Soil Erosion and Sediment Control in New Jersey,
January 2014. This document is available from the State Soil Conservation
Committee or any of the soil conservation districts listed at N.J.A.C.
2:90-1.3(a)3. The location, address, and telephone number for each
soil conservation district is available from the State Soil Conservation
Committee, PO Box 330, Trenton, New Jersey 08625. The document is
also available at http://www.nj.gov/agriculture/divisions/anr/pdf/2014NJSoilErosionControlStandardsComplete.pdf.
(2)
For the purpose of calculating runoff coefficients and groundwater recharge, there is a presumption that the preconstruction condition of a site or portion thereof is a wooded land use with good hydrologic condition. The term "runoff coefficient" applies to both the NRCS methodology above at §
161-46.7A(1)(a) and the Rational and Modified Rational Methods at §
161-46.7A(1)(b). A runoff coefficient or a groundwater recharge land cover for an existing condition may be used on all or a portion of the site if the design engineer verifies that the hydrologic condition has existed on the site or portion of the site for at least five years without interruption prior to the time of application. If more than one land cover have existed on the site during the five years immediately prior to the time of application, the land cover with the lowest runoff potential shall be used for the computations. In addition, there is the presumption that the site is in good hydrologic condition (if the land use type is pasture, lawn, or park), with good cover (if the land use type is woods), or with good hydrologic condition and conservation treatment (if the land use type is cultivation).
(3)
In computing preconstruction stormwater runoff, the design engineer
shall account for all significant land features and structures, such
as ponds, wetlands, depressions, hedgerows, or culverts, that may
reduce preconstruction stormwater runoff rates and volumes.
(4)
In computing stormwater runoff from all design storms, the design
engineer shall consider the relative stormwater runoff rates and/or
volumes of pervious and impervious surfaces separately to accurately
compute the rates and volume of stormwater runoff from the site. To
calculate runoff from unconnected impervious cover, urban impervious
area modifications as described in the NRCS Technical Release 55 -
Urban Hydrology for Small Watersheds or other methods may be employed.
(5)
If the invert of the outlet structure of a stormwater management
measure is below the flood hazard design flood elevation as defined
at N.J.A.C. 7:13, the design engineer shall take into account the
effects of tailwater in the design of structural stormwater management
measures.
B. Groundwater recharge may be calculated in accordance with the following:
the New Jersey Geological Survey Report GSR-32, A Method for Evaluating
Ground-Water-Recharge Areas in New Jersey, incorporated herein by
reference as amended and supplemented. Information regarding the methodology
is available from the New Jersey Stormwater Best Management Practices
Manual; at the New Jersey Geological Survey website at https://www.nj.gov/dep/njgs/pricelst/gsreport/gsr32.pdf
or at New Jersey Geological and Water Survey, 29 Arctic Parkway, PO
Box 420 Mail Code 29-01, Trenton, New Jersey 08625-0420.
[Added 3-9-2021 by Ord.
No. 02-2021]
A. Site design features identified under §
161-46.2F, or alternative designs in accordance with §
161-46.2G, to prevent discharge of trash and debris from drainage systems shall comply with the following standard to control passage of solid and floatable materials through storm drain inlets. For purposes of this subsection "solid and floatable materials" means sediment, debris, trash, and other floating, suspended, or settleable solids. For exemptions to this standard see §
161-46.8A(3) below.
(1)
Design engineers shall use one of the following grates whenever
they use a grate in pavement or another ground surface to collect
stormwater from that surface into a storm drain or surface water body
under that grate:
(a)
The New Jersey Department of Transportation (NJDOT) bicycle-safe
grate, which is described in Chapter 2.4 of the NJDOT Bicycle Compatible
Roadways and Bikeways Planning and Design Guidelines; or
(b)
A different grate, if each individual clear space in that grate
has an area of no more than seven square inches, or is no greater
than 0.5 inch across the smallest dimension.
(2)
For curb-opening inlets, including curb-opening inlets in combination
inlets, the clear space in that curb opening, or each individual clear
space if the curb opening has two or more clear spaces, shall have
an area of no more than seven square inches, or be no greater than
two inches across the smallest dimension.
(3)
(a)
Where each individual clear space in the curb opening in existing
curb-opening inlet does not have an area of more than nine square
inches;
(b)
Where the municipality agrees that the standards would cause
inadequate hydraulic performance that could not practicably be overcome
by using additional or larger storm drain inlets;
(c)
Where flows from the water quality design storm as specified
in N.J.A.C. 7:8 are conveyed through any device (e.g., end of pipe
netting facility, manufactured treatment device, or a catch basin
hood) that is designed, at a minimum, to prevent delivery of all solid
and floatable materials that could not pass through one of the following:
[1] A rectangular space 4.625 inches long and 1.5 inches
wide (this option does not apply for outfall netting facilities);
or
[2] A bar screen having a bar spacing of 0.5 inch.
[3] Note that these exemptions do not authorize any
infringement of requirements in the Residential Site Improvement Standards
for bicycle-safe grates in new residential development [N.J.A.C. 5:21-4.18(b)2
and 5:21-7.4(b)1].
(d)
Where flows are conveyed through a trash rack that has parallel
bars with one-inch spacing between the bars, to the elevation of the
water quality design storm as specified in N.J.A.C. 7:8; or
(e)
Where the New Jersey Department of Environmental Protection
determines, pursuant to the New Jersey Register of Historic Places
Rules at N.J.A.C. 7:4-7.2(c), that action to meet this standard is
an undertaking that constitutes an encroachment or will damage or
destroy the New Jersey Register listed historic property.
[Added 3-9-2021 by Ord.
No. 02-2021]
A. Technical guidance for stormwater management measures can be found
in the documents listed below, which are available to download from
the Department's website at http://www.nj.gov/dep/stormwater/bmp_manual2.htm.
(1)
Guidelines for stormwater management measures are contained
in the New Jersey Stormwater Best Management Practices Manual, as
amended and supplemented. Information is provided on stormwater management.
(2)
Additional maintenance guidance is available on the Department's
website at https://www.njstormwater.org/maintenance_guidance.htm.
B. Submissions required for review by the Department should be mailed
to: the Division of Water Quality, New Jersey Department of Environmental
Protection, Mail Code 401-02B, PO Box 420, Trenton, New Jersey 08625-0420
[Added 3-9-2021 by Ord.
No. 02-2021]
This section sets forth requirements to protect public safety
through the proper design and operation of stormwater management BMPs.
This section applies to any new stormwater management BMP.
A. The provisions of this section are not intended to preempt more stringent municipal or county safety requirements for new or existing stormwater management BMPs. Municipal and county stormwater management plans and ordinances may, pursuant to their authority, require existing stormwater management BMPs to be retrofitted to meet one or more of the safety standards in Subsection
B below for trash racks, overflow grates, and escape provisions at outlet structures.
B. Requirements for trash racks, overflow grates and escape provisions.
(1)
A trash rack is a device designed to catch trash and debris
and prevent the clogging of outlet structures. Trash racks shall be
installed at the intake to the outlet from the stormwater management
BMP to ensure proper functioning of the BMP outlets in accordance
with the following:
(a)
The trash rack shall have parallel bars, with no greater than
six-inch spacing between the bars;
(b)
The trash rack shall be designed so as not to adversely affect
the hydraulic performance of the outlet pipe or structure;
(c)
The average velocity of flow through a clean trash rack is not
to exceed 2.5 feet per second under the full range of stage and discharge.
Velocity is to be computed on the basis of the net area of opening
through the rack; and
(d)
The trash rack shall be constructed of rigid, durable, and corrosion-resistant
material and designed to withstand a perpendicular live loading of
300 pounds per square foot.
(2)
An overflow grate is designed to prevent obstruction of the
overflow structure. If an outlet structure has an overflow grate,
such grate shall meet the following requirements:
(a)
The overflow grate shall be secured to the outlet structure
but removable for emergencies and maintenance;
(b)
The overflow grate spacing shall be no less than two inches
across the smallest dimension; and
(c)
The overflow grate shall be constructed and installed to be
rigid, durable, and corrosion resistant and shall be designed to withstand
a perpendicular live loading of 300 pounds per square foot.
(3)
Stormwater management BMPs shall include escape provisions as
follows:
(a)
If a stormwater management BMP has an outlet structure, escape provisions shall be incorporated in or on the structure. Escape provisions include the installation of permanent ladders, steps, rungs, or other features that provide easily accessible means of egress from stormwater management BMPs. With the prior approval of the municipality pursuant to §
161-46.10C, a freestanding outlet structure may be exempted from this requirement;
(b)
Safety ledges shall be constructed on the slopes of all new stormwater management BMPs having a permanent pool of water deeper than 2 1/2 feet. Safety ledges shall be comprised of two steps. Each step shall be four feet to six feet in width. One step shall be located approximately 2 1/2 feet below the permanent water surface, and the second step shall be located one to 1 1/2 feet above the permanent water surface. See §
161-46.10D below for an illustration of safety ledges in a stormwater management BMP; and
(c)
In new stormwater management BMPs, the maximum interior slope
for an earthen dam, embankment, or berm shall not be steeper than
three horizontal to one vertical.
C. Variance or exemption from safety standard. A variance or exemption
from the safety standards for stormwater management BMPs may be granted
only upon a written finding by the municipality that the variance
or exemption will not constitute a threat to public safety.
D. Safety ledge illustration.
Elevation View - Basin Safety Ledge Configuration
|
[Added 3-9-2021 by Ord.
No. 02-2021]
A. Submission of site development stormwater plan.
(1) Whenever an applicant seeks municipal approval of a development subject to this article, the applicant shall submit all of the required components of the
Checklist for the Site Development Stormwater Plan at §
161-47C below as part of the submission of the application for approval.
(2) The applicant shall demonstrate that the project meets the standards
set forth in this article.
(3) The applicant shall submit five copies of the materials listed in the
Checklist for Site Development Stormwater Plans in accordance with §
161-47C below.
B. Site development stormwater plan approval. The applicant's site
development project shall be reviewed as a part of the review process
by the municipal board or official from which municipal approval is
sought. That municipal board or official shall consult the municipality's
review engineer to determine if all of the checklist requirements
have been satisfied and to determine if the project meets the standards
set forth in this article.
C. Submission of site development stormwater plan. The following information
shall be required:
(1) Topographic base map. The reviewing engineer may require upstream
tributary drainage system information as necessary. It is recommended
that the topographic base map of the site be submitted which extends
a minimum of 200 feet beyond the limits of the proposed development,
at a scale of one inch equals 200 feet or greater, showing two-foot
contour intervals. The map as appropriate may indicate the following:
existing surface water drainage, shorelines, steep slopes, soils,
erodible soils, perennial or intermittent streams that drain into
or upstream of the Category One waters, wetlands and floodplains along
with their appropriate buffer strips, marshlands and other wetlands,
pervious or vegetative surfaces, existing man-made structures, roads,
bearing and distances of property lines, and significant natural and
man-made features not otherwise shown.
(2) Environmental site analysis. A written and graphic description of
the natural and man-made features of the site and its surroundings
should be submitted. This description should include a discussion
of soil conditions, slopes, wetlands, waterways and vegetation on
the site. Particular attention should be given to unique, unusual,
or environmentally sensitive features and to those that provide particular
opportunities or constraints for development.
(3) Project description and site plans. A map (or maps) at the scale
of the topographical base map indicating the location of existing
and proposed buildings roads, parking areas, utilities, structural
facilities for stormwater management and sediment control, and other
permanent structures. The map(s) shall also clearly show areas where
alterations will occur in the natural terrain and cover, including
lawns and other landscaping, and seasonal high groundwater elevations.
A written description of the site plan and justification for proposed
changes in natural conditions shall also be provided.
(4) Land use planning and source control plan. This plan shall provide a demonstration of how the goals and standards of §§
161-45 and
161-46 are being met. The focus of this plan shall be to describe how the site is being developed to meet the objective of controlling groundwater recharge, stormwater quality and stormwater quantity problems at the source by land management and source controls whenever possible.
(5) Stormwater management facilities map. The following information,
illustrated on a map of the same scale as the topographic base map,
shall be included:
(a)
Total area to be disturbed, paved or built upon, proposed surface
contours, land area to be occupied by the stormwater management facilities
and the type of vegetation thereon, and details of the proposed plan
to control and dispose of stormwater.
(b)
Details of all stormwater management facility designs, during
and after construction, including discharge provisions, discharge
capacity for each outlet at different levels of detention and emergency
spillway provisions with maximum discharge capacity of each spillway.
(6) Calculations.
(a)
Comprehensive hydrologic and hydraulic design calculations for the predevelopment and post-development conditions for the design storms specified in §§
161-46.2 through
161-46.6 of this article.
(b)
When the proposed stormwater management control measures depend
on the hydrologic properties of soils or require certain separation
from the seasonal high-water table, then a soils report shall be submitted.
The soils report shall be based on on-site boring logs or soil pit
profiles. The number and location of required soil borings or soil
pits shall be determined based on what is needed to determine the
suitability and distribution of soils present at the location of the
control measure.
(7) Maintenance and repair plan. The design and planning of the stormwater management facility shall meet the maintenance requirements of §
161-48.
(8) Waiver from submission requirements. The municipal official or board reviewing an application under this article may, in consultation with the municipality's review engineer, waive submission of any of the requirements in §
161-47C(1) through
(6) of this section when it can be demonstrated that the information requested is impossible to obtain or it would create a hardship on the applicant to obtain and its absence will not materially affect the review process.
[Added 3-9-2021 by Ord.
No. 02-2021]
A. Applicability. Projects subject to review as in §
161-45 of this article shall comply with the requirements of §
161-48B and
C below.
B. General maintenance.
(1) The design engineer shall prepare a maintenance plan for the stormwater
management measures incorporated into the design of a major development.
(2) The maintenance plan shall contain specific preventative maintenance
tasks and schedules; cost estimates, including estimated cost of sediment,
debris, or trash removal; and the name, address, and telephone number
of the person or persons responsible for preventative and corrective
maintenance (including replacement). The plan shall contain information
on BMP location, design, ownership, maintenance tasks and frequencies,
and other details as specified in Chapter 8 of the NJ BMP Manual,
as well as the tasks specific to the type of BMP, as described in
the applicable chapter containing design specifics.
(3) If the maintenance plan identifies a person other than the property
owner (for example, a developer, a public agency or homeowners'
association) as having the responsibility for maintenance, the plan
shall include documentation of such person's or entity's
agreement to assume this responsibility, or of the owner's obligation
to dedicate a stormwater management facility to such person under
an applicable ordinance or regulation.
(4) Responsibility for maintenance shall not be assigned or transferred
to the owner or tenant of an individual property in a residential
development or project, unless such owner or tenant owns or leases
the entire residential development or project. The individual property
owner may be assigned incidental tasks, such as weeding of a green
infrastructure BMP, provided the individual agrees to assume these
tasks; however, the individual cannot be legally responsible for all
of the maintenance required.
(5) If the party responsible for maintenance identified under §
161-48B(3) above is not a public agency, the maintenance plan and any future revisions based on §
161-48B(7) below shall be recorded upon the deed of record for each property on which the maintenance described in the maintenance plan must be undertaken.
(6) Preventative and corrective maintenance shall be performed to maintain
the functional parameters (storage volume, infiltration rates, inflow/outflow
capacity, etc.) of the stormwater management measure, including, but
not limited to, repairs or replacement to the structure; removal of
sediment, debris, or trash; restoration of eroded areas; snow and
ice removal; fence repair or replacement; restoration of vegetation;
and repair or replacement of nonvegetated linings.
(7) The party responsible for maintenance identified under §
161-48B(3) above shall perform all of the following requirements:
(a)
Maintain a detailed log of all preventative and corrective maintenance
for the structural stormwater management measures incorporated into
the design of the development, including a record of all inspections
and copies of all maintenance-related work orders;
(b)
Evaluate the effectiveness of the maintenance plan at least
once per year and adjust the plan and the deed as needed; and
(c)
Retain and make available, upon request by any public entity with administrative, health, environmental, or safety authority over the site, the maintenance plan and the documentation required by §
161-48B(6) and
(7) above.
(8) The requirements of §
161-48B(3) and
(4) above do not apply to stormwater management facilities that are dedicated to and accepted by the municipality or another governmental agency, subject to all applicable municipal stormwater general permit conditions, as issued by the Department. https://www.njstormwater.org/maintenance_guidance.htm.
(9) In the event that the stormwater management facility becomes a danger
to public safety or public health, or if it is in need of maintenance
or repair, the municipality shall so notify the responsible person
in writing. Upon receipt of that notice, the responsible person shall
have 14 days to effect maintenance and repair of the facility in a
manner that is approved by the Municipal Engineer or his designee.
The municipality, in its discretion, may extend the time allowed for
effecting maintenance and repair for good cause. If the responsible
person fails or refuses to perform such maintenance and repair, the
municipality or county may immediately proceed to do so and shall
bill the cost thereof to the responsible person. Nonpayment of such
bill may result in a lien on the property.
C. Nothing in this section shall preclude the municipality in which
the major development is located from requiring the posting of a performance
or maintenance guarantee in accordance with N.J.S.A. 40:55D-53.
[Amended 3-28-2006 by Ord. No. 5-2006]
A. Storm sewer pipes design shall be performed using
technical procedures as outlined in American Society of Civil Engineers
(ASCE) Manual and Report on Engineer Practice No. 37. For storm sewer
pipes in public right-of-way, reinforced concrete culvert pipe (CCP)
of appropriate class shall be used.
B. A minimum cover of two feet on top of all pipes shall
be required.
C. Minimum slope for conduits shall be 0.5%. Where discharge
is made into a stream bed, adequate protection shall be provided and
the allowable velocities shall be as shown in the Standards and Specifications
for Soil Erosion and Sediment Control in New Jersey, Design of Roadside
Channels, Hydraulic Design Series No. 4, Department of Transportation,
Federal Highway Administration, or in Design Charts for Open Channel
Flow, United States Department of Commerce, Bureau of Public Works.
D. Ends of pipes starting or terminating in an open channel
shall have reinforced concrete headwalls or flared end sections.
E. Storm water pipes shall be true to line and grade.
F. Storm water structures shall be placed where lines
change horizontal or vertical alignment grade or size or are joined
by other lines. In addition, stormwater structures shall be placed
not more than 300 feet apart. Inlets shall be located to prevent gutter
flow from crossing street pavement and to prevent runoff accumulations
above curbing at all intersections and low points along the roadway.
Maximum inlet flow rate shall be based on the capacity of the type
of inlet and shall not exceed six cubic feet per second. All hydraulic
structures shall have sufficient depth to prevent overflow due to
energy losses or changes in flow.
G. All bridges and culverts shall be designed in accordance
with the following publications:
(1) New Jersey Department of Transportation Design Manual,
Bridges and Structures.
(2) United States Department of Transportation, Hydraulic
Charts for the Selection of Highway Culverts.
H. All bridges and culverts shall meet the requirements
and procedures set forth in the manuals.
I. When channels, swales or ditches are used as part
of the storm drainage system, they shall be designed in accordance
with the following publications:
(1) United States Army Corps of Engineers, Hydraulic Design
of Flood Control Channels.
(2) United States Department of Transportation, Design
of Roadside Channels, Hydraulic Design Series No. 4.
(3) New Jersey State Soil Conservation Committee, Standards
for Soil Erosion and Sediment Control in New Jersey.
J. All channels and ditches shall meet the requirements
and procedures set forth in the manuals.
K. All storm drainage systems, including connecting pipes,
inlets, manholes, swales, ditches, etc., shall be designed to adequately
carry stormwater generated from the twenty-five-year storm frequency
storm in addition to all other required provisions of this article.