A.
No person shall commence or otherwise perform any
land development activity (major or minor) in the Town of Greenburgh
that involves 500 or more square feet without first obtaining the
proper stormwater management control permit from the Town Engineer,
and all other necessary local, state and federal permits, and thereafter
comply with the requirements of this chapter.
B.
A stormwater pollution prevention plan (SWPPP) or stormwater management plan must be prepared by a New York State licensed professional engineer, architect, landscape architect, or soil scientist and submitted for review and approval by the Town Engineer prior to commencement of any major land development activity as defined by § 248-7 of this chapter.
Stormwater control measures shall be selected
by giving preference to the best management practices for pollutant
removal and flow attenuation as specified in the NYS Stormwater Management
Design Manual, the NYSDEC's Reducing the Impacts of Stormwater Runoff
from New Development, and the Westchester County Best Management Practices
Manual for Erosion and Sediment Control. The following minimum design
requirements shall apply to minor projects:
A.
It is the responsibility of an applicant to include
sufficient information in the stormwater management and erosion control
and sediment plans so that the plans may be evaluated with respect
to the environmental characteristics of the affected areas, the potential
and predicted impacts of the proposed activity on community waters
and the effectiveness and acceptability of those measures proposed
for reducing or mitigating adverse impacts.
B.
An application for stormwater management and erosion
and sediment control permits shall be made on forms provided by the
Town, and shall include the name(s) and address(es) of the owner,
contract vendee, or developer of the site, and of any consulting firm
retained by the applicant, together with the name and telephone number
of the applicant's principal contact at such firm. Each application
shall include a certification that any land clearing, construction,
or development involving the movement of earth shall be in accordance
with the plans approved and the permit issued. The permit will be
valid for the same period as the associated building or other municipal
permits. Where a building or other municipal permit is not issued,
the stormwater management and erosion and sediment control permits
shall expire within 180 days from the date of approval unless renewed
by the Town Engineer.
C.
Required information.
(1)
Each application shall be accompanied by the following,
unless specifically waived by the Town Engineer based on the scope
of the project:
(a)
A vicinity map.
(b)
A stormwater management and erosion and sediment
control plan for the site showing drainage patterns, on-site stormwater
appurtenances, wetlands, one-hundred-year floodplain, and proposed
use of the site, including areas of excavation, grading and filling.
(c)
Stormwater management improvements, including
calculations, designs and special measures regarding safety and maintenance
operations.
(d)
Stormwater conveyance system, including plans,
designs and materials to be used for improvements and erosion control
in channel sections of stormwater conveyance systems and erosion control
measures at culvert inlets and outfalls.
(2)
Stormwater shall be managed on site using stormwater
control measures designed to afford optimum protection of ground-
and surface waters. Stormwater shall be calculated in accordance with
the methodology for determining stormwater volume and flow rates using
any one of the following methods:
(3)
Stormwater control measures shall be designed based
upon the minimum twenty-five-year design storm for local conditions.
The design shall consider all existing and new impervious surfaces,
including but not limited to roof areas, driveways, patios, deck areas,
and walkways.
(4)
Stormwater control measures may include, but shall
not be limited to, dry wells of precast concrete, recharge structures,
and infiltration trenches. Such measures may also include natural
and human-made landscape features such as depressions, blind ditches,
retention ponds, swales and other such measures. Inlets to infiltration
devices shall be protected from sediment at all times in order to
maintain their capacity.
(5)
Infiltration devices shall not be installed upgradient
within 20 feet of the subsurface treatment system of a wastewater
treatment system. Infiltration devices for roadways, parking lots,
and other areas subject to vehicle traffic shall not be installed
within 100 feet of any water well, wetland or water body.
(6)
Infiltration devices and buildings shall be designed
to maintain maximum attainable horizontal distance separation from
wells, water bodies and wetlands.
(7)
The bottom of any infiltration device shall be a minimum
of two feet above seasonal high groundwater mark and two feet above
bedrock.
(8)
Temporary erosion controls shall be required to prevent
siltation of water bodies during construction.
No application for approval of a major land
development activity as defined in this chapter shall be reviewed
until the approval authority has received a stormwater pollution prevention
plan (SWPPP) prepared in accordance with the specifications in this
chapter.
A.
It is the responsibility of an applicant to include
sufficient information in the stormwater management and erosion and
sediment control plans so that the plans may be evaluated with respect
to the environmental characteristics of the affected areas, the potential
and predicted impacts of the proposed activity on community waters
and the effectiveness and acceptability of those measures proposed
for reducing or mitigating adverse impacts.
B.
An application for stormwater management and erosion
and sediment control permits shall be made on forms provided by the
Town, and shall include the name(s) and address(es) of the owner,
contract vendee, or developer of the site, and of any consulting firm
retained by the applicant, together with the name and telephone number
of the applicant's principal contact at such firm. Each application
shall include a certification that any land clearing, construction,
or development involving the movement of earth shall be in accordance
with the plans approved and the permit issued. The permit will be
valid for the same period as the associated building or other municipal
permits.
C.
Required information. Each application shall be accompanied
by the following, unless specifically waived by the Town Engineer
based on the scope of the project:
(1)
All SWPPPs shall provide the following background
information and erosion and sediment controls:
(a)
Background information about the scope of the
project, including location, type and size of the project, the existing
zoning, North arrow, scale and legend.
(b)
Site map/construction drawing(s) for the project,
including a general location map. At a minimum, the site map should
show the total site area, all improvements, areas of disturbance,
areas that will not be disturbed, existing vegetation, on-site and
adjacent off-site surface water(s), wetlands and drainage patterns
that could be affected by the construction activity, existing and
final slopes, locations of off-site material, waste, borrow or equipment
storage areas, and the location(s) of stormwater discharges(s). The
site map should be at a scale no smaller than one inch equals 100
feet (e.g., one inch equals 500 feet is smaller than one inch equals
100 feet).
(c)
Existing topography of the site and adjacent
land clearly portraying the drainage patterns of the area, including
ditches, culverts, permanent or intermittent streams, wetlands or
water bodies, existing roads and sizes of existing culverts.
(d)
The location of existing buildings, structures,
utilities, water bodies, floodplains, drainage facilities, vegetative
cover, the size and species of all trees with a trunk diameter of
six inches or greater at a point 4 1/2 feet above ground level,
paved areas, watershed divides, and other significant natural or man-made
features on the site, and adjacent land within approximately 100 feet
of the property boundaries.
(e)
Description of the soil(s) present at the site.
(f)
Construction phasing plan describing the intended
sequence of construction activities, including clearing and grubbing,
excavation and grading, utility and infrastructure installation and
any other activity at the site that results in soil disturbance. Consistent
with the New York Standards and Specifications for Erosion and Sediment
Control (Erosion Control Manual), not more than five acres shall be
disturbed at any one time unless pursuant to an approved SWPPP.
(g)
Description of the pollution prevention measures
that will be used to control litter, construction chemicals and construction
debris from becoming a pollutant source in stormwater runoff.
(h)
Description of construction and waste materials
expected to be stored on site, with updates as appropriate, and a
description of controls to reduce pollutants from these materials,
including storage practices to minimize exposure of the materials
to stormwater and spill prevention and response.
(i)
Temporary and permanent structural and vegetative
measures to be used for soil stabilization, runoff control and sediment
control for each stage of the project from initial land clearing and
grubbing to project closeout.
(j)
A site map/construction drawing specifying the
location(s), size(s) and length(s) of each erosion and sediment control
measure.
(k)
Dimensions, material specifications and installation
details for all erosion and sediment control practices, including
the siting and sizing of any temporary sediment basins.
(l)
Temporary measures that will be converted to
permanent control measures.
(m)
Implementation schedule for staging temporary
erosion and sediment control practices, including the timing of initial
placement and duration that each practice should remain in place.
(n)
Maintenance schedule to ensure continuous and
effective operation of the erosion and sediment control practice.
(o)
Name(s) of the receiving water(s).
(p)
Delineation of SWPPP implementation responsibilities
for each part of the site.
(q)
Description of structural practices designed
to divert flows from exposed soils, store flows, or otherwise limit
runoff and the discharge of pollutants from exposed areas of the site
to the degree attainable.
(r)
Any existing data that describes the stormwater
runoff at the site.
D.
Land development activities, as defined in § 248-7 of this chapter and meeting Condition 1, 2 or 3 below, shall also include water quantity and water quality controls (post construction stormwater runoff controls) as set forth in § 248-11C as applicable:
(1)
Condition 1. Stormwater runoff from land development
activities discharging a pollutant of concern to either an impaired
water identified on the Department's 303(d) list of impaired waters
or a total maximum daily load (TMDL) designated watershed for which
pollutants in stormwater have been identified as a source of the impairment.
(2)
Condition 2. Stormwater runoff from land development
activities disturbing five or more acres.
(3)
Condition 3. Stormwater runoff from a land development
activity disturbing between one and five acres of land during the
course of the project, exclusive of the construction of single-family
residences and construction activities at agricultural properties.
E.
SWPPP requirements for land development activities
meeting Condition 1, 2 or 3:
(2)
Description of each post construction stormwater management
practice.
(3)
Site map/construction drawing(s) showing the specific
location(s) and size(s) of each post construction stormwater management
practice.
(4)
Hydrologic and hydraulic analysis for all structural
components of the stormwater management system for the applicable
design storms.
(5)
Comparison of post development stormwater runoff conditions
with predevelopment conditions.
(6)
Dimensions, material specifications and installation
details for each post construction stormwater management practice.
(7)
Maintenance schedule to ensure continuous and effective
operation of each post construction stormwater management practice.
The SWPPP shall be prepared by a New York State
licensed professional engineer, architect, landscape architect or
soil scientist, and must be signed by the professional preparing the
plan who shall certify that the design of all stormwater management
practices meet the requirements in this chapter.
The applicant shall assure that all other applicable
environmental permits have been or will be acquired for the land development
activity prior to approval of the final stormwater design plan.
A.
Each contractor and subcontractor identified in the
SWPPP to be involved in soil disturbance and/or stormwater management
practice installation shall sign and date a copy of the following
certification statement before undertaking any land development activity:
"I certify under penalty of law that I understand and agree to comply
with the terms and conditions of the stormwater pollution prevention
plan. I also understand that it is unlawful for any person to cause
or contribute to a violation of water quality standards."
B.
The certification must include the name and title
of the person providing the signature, the address and telephone number
of the contracting firm, the address (or other identifying description)
of the site and the date the certification is made.
C.
The certification statement(s) shall become part of
the SWPPP for the land development activity.
A copy of the approved SWPPP shall be retained
at the site of the land development activity during construction,
from the date of initiation of construction activities to the date
of final stabilization.
