[HISTORY: Adopted by the Town Board of the Town of Cornwall 2-8-2010 by L.L. No.
2-2010. Amendments noted where applicable.]
GENERAL REFERENCES
Clearing and grading — See Ch. 75.
Fire prevention and building code administration — See Ch. 84.
Flood damage prevention — See Ch. 87.
Freshwater wetlands — See Ch. 90.
Sewers and sewage disposal — See Ch. 119.
Subdivision of land — See Ch. 125.
Water — See Ch. 150.
Zoning — See Ch. 158.
A.
It is the purpose of this chapter to:
(1)
Establish minimum acceptable standards for stormwater management
facilities within the Town of Cornwall. The obligation to meet these
minimum acceptable standards shall be the sole responsibility of the
person or entity proposing any new subdivision, development and/or
site plan where such stormwater facilities will be required and utilized.
(2)
Meet the requirements of the SPDES general permit for MS4s.
(3)
Require land development activities to conform to the substantive
requirements of the New York State SPDES general permit for construction
activities, Permit No. GP-0-08-001 ("SPDES general permit for construction
activities").
(4)
Minimize increases in stormwater runoff from land development activities
in order to reduce flooding, siltation, increases in stream temperature,
and stream bank erosion and maintain the integrity of stream channels.
(5)
Minimize increases in pollution caused by stormwater runoff from
land development activities that would otherwise degrade local water
quality.
(6)
Reduce stormwater runoff rates and volumes, soil erosion and nonpoint
source pollution, wherever possible, through stormwater management
practices and to ensure that these management practices are properly
maintained and eliminate threats to public safety.
B.
Given that improperly managed stormwater runoff can increase the
incidence of flooding and erosion and thus adversely affect human
life, flora and fauna, this chapter has the following objectives:
(1)
To protect, maintain and enhance both the immediate and long-term
health, safety and general welfare of the citizens of the Town of
Cornwall.
(2)
To prevent damage from flooding.
(3)
To protect, restore and maintain the chemical, physical and biological
integrity of community waters.
(4)
To encourage protection of natural drainage systems, such as wetlands,
and use them in ways that do not impair their beneficial functioning.
(5)
To protect, restore and maintain the habitat of fish and wildlife.
(6)
To assure the attainment of these objectives by requiring the approval
and implementation of stormwater pollution prevention plans (SWPPPs)
for all regulated activities that may adversely impact surrounding
areas.
A.
Interpretation and usage. Unless specifically defined below, words
or phrases shall be interpreted so as to give them the meanings they
have in common usage and to give this chapter its most effective application.
Words used in the singular shall include the plural, and the plural
shall include the singular; words used in the present tense shall
include the future tense. The word "shall" denotes mandatory requirements;
the word "may" is permissive.
B.
ADVERSE IMPACTS
AGRICULTURAL ACTIVITY
APPLICANT
BUILDING
CHANNEL
CLEARING
DESIGN MANUAL
DEVELOPER
DEVELOPMENT or DEVELOPMENT ACTIVITY
(1)
(2)
(3)
DRAINAGE SYSTEM
EROSION AND SEDIMENT CONTROL PLAN
EROSION CONTROL MANUAL
GRADING
IMPERVIOUS SURFACE
INFILTRATION
LAND DEVELOPMENT ACTIVITY
MAINTENANCE AGREEMENT
NONPOINT SOURCE POLLUTION
NYSDEC
OWNER
PERSON
PHASING
RECEIVING BODY OF WATER
REGULATED WETLAND
SEDIMENT
SEDIMENT CONTROL
SITE
SPDES
SPDES GENERAL PERMIT FOR CONSTRUCTION ACTIVITIES
SPDES GENERAL PERMIT FOR MS4s
STABILIZATION
STORMWATER MANAGEMENT FACILITY
STORMWATER MANAGEMENT OFFICER
STORMWATER MANAGEMENT PRACTICES
STORMWATER POLLUTION PREVENTION PLAN (SWPPP)
STORMWATER RUNOFF
STRUCTURE
SURFACE WATERS OF THE STATE OF NEW YORK
WATER BODY
WATERCOURSE
WATERSHED
WATERS or PUBLIC WATERS
Definitions. As used in this chapter, the following terms shall have
the meanings indicated:
Any modifications, alterations or effects on a feature or
characteristic of public waters, wetlands or adjacent lands, including
their quality, quantity, hydrology, surface area, species composition,
living resources, aesthetics or usefulness for human or natural uses
which are or may potentially be harmful or injurious to human health,
welfare, safety or property, to biological productivity, diversity
or stability or which unreasonably interfere with the enjoyment of
life or property, including outdoor recreation.
The activity of an active farm, including grazing and watering
livestock, irrigating crops, harvesting crops, using land for growing
agricultural products, and cutting timber for sale, but shall not
include the operation of a dude ranch or similar operation, or the
construction of new structures associated with agricultural activities.
An owner or agent of an owner who has filed an application
for a land development activity.
Any structure, either temporary or permanent, having walls
and a roof, designed for the shelter of any person, animal, or property,
and occupying more than 100 square feet of area.
A natural or artificial watercourse with a definite bed and
banks that conducts continuously or periodically flowing water.
Any activity that removes the vegetative surface cover.
The New York State Stormwater Management Design Manual, most
recent version, including applicable updates, which serves as the
official guide for stormwater management principles, methods and practices.
Any person who engages in development either as the owner
or the agent of the owner.
Construction, installation, alteration, demolition or removal
of a structure, impervious surface or drainage system;
Clearing, scraping, grubbing or otherwise removing or killing
the vegetation of a site; or
Adding, removing, exposing, excavating, leveling, grading, digging,
burrowing, dumping, piling, dredging or otherwise disturbing the soil,
mud, sand or rock on a site which could otherwise cause deleterious
conditions as noted hereinabove.
The system through which water flows from the land, including
watercourses, water bodies, groundwater and wetlands.
A set of plans prepared by a licensed/certified professional
indicating the specific measures and sequencing to be used to control
sediment and erosion on a development site during construction.
The most recent version of the "New York Standards and Specifications
for Erosion and sediment Control" manual, commonly known as the "Blue
Book."
Excavation or fill of material, including the resulting conditions
thereof.
A surface which has been compacted or covered with a layer
of material so that it is highly resistant to infiltration by water,
including, but not limited to, semi-impervious areas such as compacted
clay, conventionally surfaced streets, roofs, sidewalks, parking lots
and other similar structures.
The process of percolating stormwater into the subsoil.
Construction activity, including clearing, grading, excavating,
soil disturbance or placement of fill, that results in land disturbance
of equal to or greater than one acre, or activities disturbing less
than one acre of total land area that is part of a larger common plan
of development or sale, even though multiple separate and distinct
land development activities may take place at different times on different
schedules.
A legally recorded document that provides for long-term maintenance
of stormwater management practices amongst one or more lot owners.
Pollution from any source other than from any discernible,
confined, and discrete conveyances, and shall include, but not be
limited to, pollutants from agricultural, silvicultural, mining, construction,
subsurface disposal and urban runoff sources.
The New York State Department of Environmental Conservation.
The person in whom is vested either a) the fee ownership,
dominion or title of property; b) possession of property; or c) the
responsibility to maintain property. This term may also include a
tenant, if chargeable under his lease for the maintenance of the property,
and any agent of the owner or tenant, including a developer.
Any and all persons, natural or artificial, and includes
any individual, firm, corporation, government agency, business trust,
partnership, association, two or more persons having a joint or common
interest or any other legal entity.
Clearing a parcel of land in distinct pieces or parts, with
the stabilization of each piece completed before the clearing of the
next.
Any water body, watercourse or wetland into which surface
waters flow either naturally, in man-made ditches or in closed conduit
systems.
Any area meeting the requirements of the "Federal Manual
for Identifying and Delineating Jurisdictional Wetlands" (latest edition),
and/or any area mapped or delineated or otherwise designated by the
NYSDEC as being a state-protected wetland. NYSDEC-regulated wetlands
shall include the NYSDEC-regulated adjacent area.
The fine particulate material, whether mineral or organic,
that is in suspension or has settled in a water body.
Measures that prevent eroded sediment from leaving the site.
Any tract, lot or parcel of land, or combination thereof,
which is under single ownership or is contiguous and in diverse ownership
where development is to be performed as part of a unit, subdivision
or project.
The State Pollution Discharge Elimination System program,
as codified in Article 17 of the New York Environmental Conservation
Law, and the regulations and permits issued thereunder.
An SPDES general permit issued by the NYSDEC which regulates
disturbances of land resulting from construction activities. Any reference
to the general permit is to the version in effect at the time of the
review and approval of the SWPPP.
An SPDES general permit issued by the NYSDEC that requires
municipalities to regulate discharges from municipal separate storm
sewers. Any reference to the general permit is to the version in effect
at the time of the review and approval of the SWPPP.
The use of practices to prevent exposed soil from eroding.
One or a series of stormwater management practices installed,
stabilized and operating for the purpose of controlling stormwater
runoff.
An employee or officer designated by the municipality to
review and approve stormwater pollution prevention plans and to inspect
sites subject to this chapter and to enforce its requirements. Plan
reviews and site inspections may be delegated to a consulting engineer
or a consultant. If the project is referred by the Town to a consulting
engineer or consultant, the applicant shall deposit funds into an
escrow account to defray the review costs. The amount of the deposit
shall be determined by the Planning Board upon advice of the Board's
consultants.
Measures, either structural or nonstructural, that are determined
to be the most effective, practical means of preventing flood damage
and preventing or reducing point source or monopoint source pollution
inputs to stormwater runoff and water bodies.
A set of plans prepared by or under the direction of a licensed/certified
professional indicating the specific measures and sequencing to be
used to control stormwater on a development site during and after
construction.
Stormwater flow on the surface of the ground resulting from
rainwater, surface runoff, snowmelt and drainage.
That which is built or constructed, an edifice or building
or any piece of work artificially built or composed of parts joined
together in some definite manner, but shall not include fences or
signs.
Lakes, bays, sounds, ponds, impounding reservoirs, springs,
wells, rivers, streams, creeks, estuaries, marshes, inlets, canals,
the Atlantic Ocean within the territorial seas of the State of New
York and all other bodies of surface water, natural or artificial,
inland or coastal, fresh or salt, public or private (except those
private waters that do not combine or effect a junction with natural
surface or underground waters), which are wholly or partially within
or bordering the state or within its jurisdiction. Storm sewers and
waste treatment systems, including treatment ponds or lagoons which
also meet the criteria of this definition are not waters of the state;
this exclusion applies only to man-made bodies of water which neither
were originally created in waters of the state (such as a disposal
area in wetlands) nor resulted from impoundment of waters of the state.
Any natural or artificial pond, lake, reservoir or other
area which ordinarily or intermittently contains water and which has
a discernible shoreline.
A permanent or intermittent stream or other body of water,
either natural or man-made, which gathers or carries surface water.
A drainage area or basin contributing to the flow of water
in a receiving body of water.
Any and all water on or beneath the surface of the ground.
It includes the water in any watercourse, water body or drainage system.
It also includes diffused surface water and water standing, percolating
or flowing beneath the surface of the ground.
A.
Unless exempted pursuant to Subsection C below, an SWPPP must be submitted and approved by the Stormwater Management Officer before:
B.
Following the review and approval of the SWPPP by the Stormwater
Management Officer, an applicant and the owner, and such other designated
responsible party or parties, shall be responsible for the implementation
and maintenance of the SWPPP.
C.
Exemptions. The following development activities are exempt from the requirements of Subsections A and B above:
(1)
Land development activity which does not disturb more than one acre
(43,560 square feet); provided, however, for projects which disturb
between 10,000 square feet and 43,560 square feet, an erosion and
sediment control plan shall be designed, approved, implemented and
maintained as directed by the Stormwater Management Officer.
(2)
Agricultural activity; provided, however, that for such activities
involving the construction of structures disturbing more than 10,000
square feet, an erosion and sediment control plan shall be designed,
approved, implemented and maintained as directed by the Stormwater
Management Officer.
(3)
Any maintenance, alteration, use or improvement to an existing structure
not changing or affecting quality, rate or location of surface water
discharge.
(4)
Silvicultural activities, provided that the guidelines and requirements
of sound forestry management practices as established by the NYSDEC
are met.
(5)
Routine maintenance activities that disturb less than one acre and
are performed to maintain the original line and grade, hydraulic capacity
or original purpose of a facility.
(6)
Repairs to any stormwater management facility deemed necessary by
the Stormwater Management Officer or by the NYSDEC.
(7)
Cemetery graves.
(8)
Installation of fencing, signage, telephone and electric poles and
other kinds of posts or poles.
(9)
Emergency activities necessary to protect life, property or natural
resources.
(10)
Activities of an individual engaging in home gardening by growing
flowers, vegetables and other plants primarily for use by that person
and his or her family.
(11)
Landscaping and horticultural activities in connection with
an existing structure.
(12)
Land development activities for which a building permit has
been issued prior to the effective date of this chapter.
(13)
Land development activities in connection with any subdivision
or site plan which has received conditional final or final approval
from the Town of Cornwall Planning Board prior to the effective date
of this chapter.
An SWPPP must demonstrate that the proposed development or activity
has been planned and designed and will be constructed and maintained
to meet each of the following standards:
A.
To ensure that after development, runoff from the site maintains
the rate of flow and quality of runoff that would have occurred following
the same rainfall under existing conditions;
B.
To maintain the existing hydraulic and characteristics of the watershed;
C.
To protect the quality of surface waters;
D.
To protect groundwater quality and levels;
E.
To protect the beneficial functioning of wetlands as areas for the
natural storage of surface waters and the chemical reduction and assimilation
of pollutants;
F.
To prevent increased flooding and damage that results from improper
location, construction and design of structures in areas that are
presently subject to an unacceptable danger of flooding;
G.
To minimize injury to flora and fauna and adverse impacts to fish
and wildlife habitat; and
H.
To further the objectives of this chapter.
A.
It is the applicant's responsibility to include sufficient information
in the SWPPP for the Stormwater Management Officer or his designate
to evaluate the environmental characteristics of the affected areas,
the potential and predicted impacts of the proposed activity on public
waters and adjacent lands, and the effectiveness and acceptability
of those measures proposed by the applicant for reducing adverse impacts.
The SWPPP shall contain all material necessary to communicate the
information required by this section.
B.
All calculations, assumptions, criteria and references used in the
design of new facilities, examination of existing facilities and comparison
of pre- to post-development discharges shall be included with the
plan.
C.
All stormwater management data must be prepared and sealed by individuals
licensed or certified in New York State to perform such duties.
D.
The SWPPP shall contain the name, address and telephone number of
the owner and the developer. In addition, a survey prepared by a surveyor
licensed in New York State and a legal description of the property
shall be provided, and its location with reference to such landmarks
as major water bodies, adjoining roads, railroads, subdivisions or
other municipalities shall be clearly identified on a location map.
E.
The existing environmental and hydrologic conditions of the site
and of receiving waters and wetlands shall be described in detail,
including the following:
(1)
A plan showing the pre-development conditions of the site at a scale
of at least one inch equals 50 feet and a map at a scale of at least
one inch equals 500 feet showing all contributory drainage areas to
the study point, or such other scale as deemed appropriate by the
Stormwater Management Officer.
(2)
The flow rate of stormwater runoff under existing conditions.
(3)
The names and description of all watercourses, water bodies and wetlands
on or adjacent to the site or into which the stormwater flows. Information
regarding the existing water quality, if any, and the receiving water
quality classification as determined by the NYSDEC shall be included.
(4)
Groundwater levels from readily available data sources.
(5)
The location of floodplains.
(6)
Land cover.
(7)
Topography at two-foot contour intervals, based on actual data.
(8)
Soils, including erodibility, percolation rate, depth to groundwater
and depth to bedrock, etc.
F.
Proposed alterations of the site shall be described in detail and
shown on plans at a scale of at least one inch equals 50 feet, or
such other scale as deemed appropriate by the Stormwater Management
Officer, and shall include:
(1)
Changes in topography, with all grading shown with two-foot contour
intervals or less;
(2)
Limits of proposed disturbed area;
(3)
Proposed ground coverage, i.e., pavement, gravel, houses, buildings,
lawns, etc., and their areas;
(4)
Construction phasing plans 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 Erosion
Control Manual, no more than five acres shall be disturbed at any
one time unless a waiver for such excess disturbance has been granted
by the NYSDEC;
(5)
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;
(6)
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;
(7)
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;
(8)
A site map/construction drawing(s) specifying the locations, size
and length of each erosion and sediment control practice;
(9)
Dimensions, material specifications and installation details for
all erosion and sediment control practices, including the siting and
sizing of any temporary sediment basins;
(10)
Temporary practices that will be converted to permanent control
measures;
(11)
Implementation schedule for tagging temporary erosion and sediment
control practices, including the timing of initial placement and duration
that each practice should remain in place;
(12)
Maintenance schedule to ensure continuous and effective operation
of the stormwater management practices and stormwater management facilities;
(13)
Name(s) of the receiving water(s);
(14)
Delineation of SWPPP implementation responsibilities for each
part of the site;
(15)
Description of structural practices designed to divert flows
from exposed soils, store flows, or otherwise limit runoff and the
discharge of pollutant from exposed areas of the site to the degree
attainable; and
(16)
Any existing data that describes the stormwater runoff at the
site.
G.
All components of the drainage system and any measures for the detention,
retention or infiltration of water or for the protection of water
quality shall be described in detail, including:
(1)
The channel, direction, flow rate and quality of stormwater that
will be conveyed from and/or through the site, with a comparison to
the existing conditions. In no case will any facility or construction
be allowed that raises the existing water surface elevation on upstream
or downstream properties, unless specifically agreed to by those property
owners;
(2)
Detention, retention and/or infiltration structures, including plans
for the discharge of contained waters, and maintenance plans.
(3)
A tabulation of water quality volumes and storage, discharge curves
with corresponding water surface elevations, inflow hydrographs, outflow
hydrographs and dewatering/infiltration times shall be submitted with
all plans utilizing detention, retention and infiltration facilities.
(4)
All plans, with defined subcatchment areas, and profiles of the proposed
drainage facilities, including the size and type of material.
(5)
An erosion and sediment control plan for all development activities.
(6)
All calculations and design information in accordance with the design
section of this chapter and as may be required pursuant to the SPDES
general permit for construction activities or the SPDES general permit
for MS4s, as in effect at the time of the review.
(7)
General specifications for the construction of all components of
the drainage system.
(8)
Any other information that the Stormwater Management Officer or his
designated representative determines is reasonably necessary to evaluate
the SWPPP or to meet the requirements of this chapter.
H.
All charges for the technical review of the SWPPP shall be charged
against the applicant's escrow. If the escrow is depleted, the
applicant must pay all charges prior to the final approval of the
SWPPP.
To ensure attainment of the objectives of this chapter and to
ensure that performance standards will be met, the design, construction
and maintenance of drainage systems shall be consistent with the following
standards:
A.
In the interest of reducing the total area of impervious surface,
preserving existing features that are critical to stormwater management,
and reducing the concentration of stormwater flow, maximum use shall
be made of existing on-site natural and man-made stormwater management
facilities.
B.
Innovative stormwater management facilities may be proposed (e.g.,
rooftop storage, underground storage structures and infiltration systems),
provided that they are accompanied by detailed engineering plans and
demonstrate performance capabilities that are acceptable to the Stormwater
Management Officer.
C.
Stormwater management facilities shall be provided so the peak discharge
of the calculated post-development runoff to an adjacent property,
watercourse or water body does not exceed the peak discharge of the
pre-development runoff. Point discharge of stormwater runoff to an
adjacent property, watercourse or water body will not be allowed in
the post-development design if one did not exist in the predevelopment
condition. Point discharge is required to be returned to sheet flow
or an easement will be required to be obtained from the adjoining
property owner if this condition cannot be met.
D.
Runoff calculations for the pre-development and post-development
comparison shall consider the one-year, ten-year, twenty-five-year,
and one-hundred-year storm frequencies.
E.
For pre-development computations, the runoff coefficient within the
study area shall be based on present land use conditions.
F.
Retention and detention basins in compliance with NYSDEC standards
and guidelines, and other approved alternatives, shall be used to
retain and detain the increased and accelerated runoff and reduce
pollutants in runoff that the development generates. Water shall be
released from these areas at a rate equal to or less than the pre-development
conditions of the storm event. Measures shall be taken to protect
the outfall area from erosion. Water quality volume shall be addressed
by any proposed post-development design.
G.
Retention/detention basins shall be designed to safely discharge
the peak discharge from the post-development one-hundred-year storm
frequency event through an emergency spillway in a manner which will
not damage the integrity of the basin or cause damage to adjoining
properties.
H.
Retention/detention basins shall be landscaped in accordance with
current engineering practices and in accordance with the Erosion Control
Manual, latest edition or revision.
I.
Retention/detention basins that may be used to collect sediment during
construction must have all sediment removed at any time that it is
at 60% of its original capacity. Upon completion of all construction,
any sediment in the basin must be removed and the basin shall be reshaped
to the design dimensions and stabilized. A maintenance schedule must
be provided indicating how often the basin is to be cleaned thereafter
and who is responsible for cleaning it.
J.
Retention/detention basins that are designed with a dam shall incorporate
the following minimum standards:
(1)
The maximum water depth shall not exceed 10 feet unless approved
by waiver of the Planning Board.
(2)
The minimum top width of dams shall be 10 feet.
(3)
The side slopes of earth fill dams shall not be steeper than three
feet horizontal to one foot vertical on the downstream side of the
embankment.
(4)
Basins without restricted access shall have impoundment areas with
side slopes no greater than five feet horizontal on one foot vertical.
(5)
A cutoff trench of impervious material shall be provided under all
dams.
(6)
All pipes and culverts through dams shall have properly spaced cutoff
collars or factory-welded antiseep collars.
(7)
A minimum of one foot freeboard, computed from the maximum water
surface elevation during the one-hundred-year storm event, shall be
provided in all basins.
(8)
The minimum floor elevation of all structures that would be affected
by a basin or other water impoundments or open conveyance systems
where ponding may occur shall be two feet above the one-hundred-year
water surface elevation.
K.
Runoff calculations for stormwater management facilities shall be
based upon the following methods:
(1)
SCS - TR-20 (latest revision) is the recommended and preferred method
for the study of watersheds with a drainage area greater than 100
acres. SCS - TR-20 or SCS - TR-55 Tabular Hydrograph Method (latest
revision) may be used for the study of watersheds with a drainage
area greater than 200 acres.
(2)
SCS - TR-55 Graphical Peak Method (latest revision) may be used in
lieu of the Tabular Hydrograph Method for sizing conveyance systems
or checking peak flows only. It shall not be used for basin routing
or subarea routing as it does not provide an adequate hydrograph.
(3)
Other standard engineering models with approval of the Stormwater
Management Officer.
(4)
Stormwater runoff shall be based on the following twenty-four-hour
storm events with a Type III distribution:
Storm Event
|
Inches of Rainfall
| |
---|---|---|
1-year
|
2.9
| |
10-year
|
5.5
| |
100-year
|
8.0
|
source: SCS Technical Release 55
|
(5)
Use of other criteria, assumptions, references, calculation methods
and computer programs may be utilized, provided that detailed design
information and programming, with references, are submitted to and
found acceptable by the Stormwater Management Officer prior to submission
of the SWPPP.
L.
The design plan and construction schedule shall incorporate measures
to minimize soil erosion and sedimentation.
M.
Consideration shall be given to the relationship of the subject property
to the drainage pattern of the watershed.
N.
Stormwater runoff shall not be transferred from one watershed to
another unless:
(1)
The watersheds are subwatersheds of a common watershed which join
together within the perimeter of the property;
(2)
The effect of the transfer does not alter the peak discharge onto
adjacent lands, watercourse or water bodies at any point; and
(3)
Easements from the affected landowners are provided, if deemed necessary
by the Stormwater Management Officer.
O.
Technical references. For the purpose of this chapter, the following
documents shall serve as the official guides and specifications for
stormwater management. Stormwater management practices that are designed
and constructed in accordance with these technical documents shall
be presumed to meet the standards imposed by this law:
P.
Technical standards.
(1)
For all swales and gutters, the Manning's roughness coefficient
"n" factors used to determine capacity and velocity shall be based
on accepted engineering practices.
(2)
Corrugated metal pipe will not be allowed to be used in any drainage
system or facility without the approval of the Town Superintendent
of Highways, the Stormwater Management Officer and the Town Engineer.
If allowed, corrugated metal pipe shall be fully asphalt-coated with
paved inverts, and the "n" factor shall be twenty-two thousandths
(0.022) for annular pipe and seventeen thousandths (0.017) for helical
pipe.
(3)
The "n" factor for concrete pipe shall be thirteen thousandths (0.013).
(4)
The "n" factor for polyethylene pipe shall be ten thousandths (0.010)
for smooth interior pipe and nineteen thousandths (0.019) for corrugated
interior pipe.
(5)
Manufacturer's specifications may be submitted to the Stormwater
Management Officer and Town Engineer for acceptance if other types
of pipes or sizes of pipes indicate that another value of "n" should
be used.
(6)
Catch basins shall be designed with a sump of 16 inches.
(7)
Catch basin inlet capacity shall be based on design data provided
by the manufacturer.
(8)
Any existing drainage structures within 200 feet of the site shall
be included in the SWPPP. Structures that convey streams shall be
checked to determine if they have the capacity to carry the fifty-year
storm flow, and all other structures shall be checked for capacity
to carry the twenty-five-year storm flow.
(9)
A tabulation of flows through all drainage systems shall be submitted
with the plans.
(10)
Culvert design shall consider inlet/outlet control at each structure
or hydraulic losses shall be calculated through the system. These
calculations are to be submitted as part of the SWPPP. At a minimum,
when pipe sizes change, the tops of the pipes shall match in elevation.
(11)
All culverts having diameters of 24 inches to 48 inches shall
have a removable inlet grating of five-eighths-inch diameter (minimum)
reinforcing bars spaced approximately six inches on center. All design
calculations are to reflect this inlet control condition.
Q.
Catch basins shall be located in the swale along open section roadways.
The calculated depth of flow in the swale shall not exceed 1/2 of
the total depth of the swale before placing a catch basin. The catch
basin shall be capable of accepting 100% of the flow in the swale,
based on a twenty-five-year return frequency storm event. On closed
section roadways, catch basins shall be located along the curbline
and are not permitted along the curb radius at intersections. For
the purpose of catch basin placement, the depth of flow along the
curb and across intersections shall not exceed two inches.
R.
Manholes and catch basins shall not be spaced more than 300 feet
apart. Structures shall be placed at all points of changes in horizontal
or vertical direction.
S.
Stormwater collection systems shall have a minimum diameter of 15
inches and shall be designed to have a minimum velocity of two feet
per second. However, at the terminus of the system, the flow velocity
at the discharge point shall not exceed four feet per second prior
to the flow entering a natural watercourse, water body or adjacent
property.
T.
The maximum swale, gutter or curb velocity of stormwater runoff shall
be maintained at levels that result in a stable condition both during
and after construction. Swales shall be designed and stabilized in
accordance with the Erosion Control Manual. Swales shall be designed
to allow for infiltration of stormwater runoff and removal of pollutants
from the runoff whenever possible. This can be accomplished by keeping
the swale at as flat a slope as possible, stabilizing the swale with
a water-tolerant erosion-resistant grass that will not be mowed close
to the ground, increasing the percolation ability of the swale by
tilling the soil before establishing vegetative cover and installing
check dams with riprap on the downstream side to prevent scouring.
U.
Stormwater management facilities that are not offered for dedication
to the Town and not located within a public right-of-way shall be
located within an area subject to a drainage easement.
V.
When applications are submitted in separate sections, each section
shall control stormwater runoff and sedimentation as though it were
a separate entity. If temporary facilities are required for construction
of a section, they shall meet all of the requirements of this chapter.
A construction or phasing schedule shall be submitted with each SWPPP
and shall demonstrate the methods to be used to minimize stormwater
runoff and soil erosion and sedimentation.
W.
Stormwater management facilities shall not be constructed within
or discharge directly to a regulated wetland, adjacent areas or existing
water bodies unless:
(1)
The appropriate permits or approvals from all applicable regulatory
agencies for any disturbances to such regulated resources have been
obtained; or
(2)
A letter from said agencies has been obtained stating that a permit
is not required for the proposed work; and
(3)
Copies of such permits or letters shall be submitted to the Stormwater
Management Officer prior to the final approval of the SWPPP.
X.
Individual lots, buildings and dwellings shall be provided with drainage
facilities to assure proper runoff from roofs, driveways, paved areas
and footing drains. Footing drains shall discharge to free-flowing
outlets. The installation of such facilities shall be in accordance
with the requirements of this chapter and the Town of Cornwall Road
Specifications[1] and must be installed prior to the issuance of a certificate
of occupancy.
Y.
Any land development activity shall not cause an increase in turbidity
that will result in substantial visible contrast to natural conditions
in surface waters of the state of New York.
Z.
Stormwater discharges should be consistent with the thermal criteria
found in the Water Quality Regulations, 6 NYCRR Part 704.
AA.
Contractor certification.
(1)
Each contractor and subcontractor identified in the SWPPP who will
be involved in soil disturbance and/or stormwater management facilities
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 Management
Plan. I also understand that it is unlawful for any person to cause
or contribute to violation of water quality standards."
|
(2)
The certification must include the name and title of the person providing
the signature, address, and telephone number of the contracting firm;
the address (or other identifying descriptions) of the site; and date
the certification is made.
(3)
The certification statement(s) shall become part of the SWPPP for
the land development activity.
BB.
In the event of any conflict between the requirements of this chapter
and the SPDES general permit for construction or the SPDES general
permit for MS4s, the requirements of the SPDES general permits shall
control.
A.
The applicant shall reserve easements or drainage rights-of-way within
the subdivision or site plan where stormwater management facilities
are existing or proposed, whether man-made or natural. Easements shall
conform as closely as possible to the lines of such course and shall
also meet the following criteria:
(1)
Easements shall have a minimum width of 20 feet and shall be adequately
designed to provide area for the collection and discharge of water,
the maintenance and repair of the facility, and the passage of equipment
for such work.
(2)
In the case of streams or open-channel drainage, the easement shall
encompass the one-hundred-year storm event or the flood of record,
plus one foot freeboard above that elevation. Calculations acceptable
to the Stormwater Management Officer supporting those elevations shall
be submitted with the SWPPP.
(3)
When a proposed drainage system carries water onto adjacent lands
where no discharge point existed in the pre-developed condition, stormwater
will be returned to a sheet flow condition prior to exit from the
site, or an easement must be obtained from the downstream property
owners(s).
(4)
The SWPPP and easements shall clearly indicate who has the right
of access and the responsibility of maintenance for all stormwater
management facilities.
(5)
The stormwater management facilities maintained by the owner or other
responsible entity shall be subject to adequate easements to permit
the Town to inspect and, if necessary, to take corrective measures
should the owner fail to properly maintain the system.
B.
Maintenance. Unless the Town Board determines to accept the responsibility
of maintaining the stormwater management facilities, it shall be the
responsibility of the owner and subsequent landowners, if applicable,
to maintain the proposed stormwater management facilities as it was
designed and constructed, in accordance with the following minimum
requirements:
(1)
As specified in an approved SWPPP, good maintenance involves periodic
cleaning and dredging of pipes and basins and mowing and maintaining
proper land cover. Sediment shall be removed from sediment traps or
sediment ponds whenever their design capacity has been reduced by
50%.
(2)
The stormwater management facilities installed in accordance with
this chapter shall be operated and maintained by the owner to achieve
the goals of this chapter. Proper operation and maintenance also includes,
as a minimum, the following:
(a)
A preventive/corrective maintenance program for all stormwater
management facilities and systems of treatment and control (or related
appurtenances) that are installed or used to achieve the requirements
of this chapter.
(b)
Written procedures for operation and maintenance and training
new maintenance personnel.
C.
Stormwater management facilities and related improvements may become
part of a drainage district upon the approval by the Town Board in
accordance with the procedures set forth in Article 12 of the New
York Town Law, in which case the maintenance of the stormwater management
facilities and related improvements shall be the responsibility of
the Town.
D.
Maintenance agreements. If the future maintenance of stormwater management
facilities shall be the responsibility of more than one owner or entity,
a maintenance agreement for stormwater management facilities, in form
and content acceptable to the Stormwater Management Officer and attorney
for the Town and binding on all subsequent landowners, must be recorded
in the office of the County Clerk prior to the issuance of any final
plan or plat approval.
A.
Performance security to ensure that the initial construction of stormwater
management facilities and related improvements shall be provided in
an amount approved by the Town Board upon the recommendation of the
Stormwater Management Officer and in a form approved by the attorney
for the Town. The applicant's engineer or licensed or certified
design professional shall prepare the estimate and submit it to the
Stormwater Management Officer for review and recommendation to the
Town Board.
B.
The estimated costs of the following improvements associated with
the SWPPP or erosion and sediment control plan must be included in
the amount of the performance security:
(1)
Stormwater management facilities, including but not limited to catch
basins, manholes, pipes, swales, basins, infiltration systems;
(2)
Erosion and sediment control, including grading and stabilization;
(3)
As-built or record drawings; and
(4)
Any other items that may be required by the Stormwater Management
Officer.
C.
Performance security shall be delivered to the Town Clerk, with copies
provided to the Stormwater Management Officer and the Building Inspector,
to guarantee to the Town that the developer will construct and complete
the required public improvements, within a reasonable time as determined
by the Stormwater Management Officer.
D.
Prior to construction, and, if the stormwater management facilities
are a component of an application before the Planning Board, then
prior to the Planning Board's grant of final approval of a subdivision
plat or site plan, the applicant shall follow the procedure set forth
below:
(1)
In an amount set by the Town Board, the applicant shall either file
with the Town Clerk a certified check to cover the full cost of the
required improvements or an adequate and acceptable security issued
by a bank or surety company approved by the Town Board to cover the
full cost of the required improvements, or any combination thereof.
Any such security shall comply with the requirements of § 277
of the Town Law and, further, shall be satisfactory to the Town Board
and the Town Attorney as to form, sufficiency, manner of execution
and surety. A period of three years shall be set forth in the document
of surety within which required improvements must be completed. However,
the term of such performance security may be required to be extended
and the amount of the security increased by the Town Board if improvements
are not completed within the original term of the security.
(2)
If the improvements are dedicated to the Town, then the required
improvements shall not be considered complete until the installation
of the improvements has been accepted by the Town and the Stormwater
Management Officer has accepted as-built or record drawings.
E.
The applicant shall complete all required improvements or post the
required performance security, prior to the issuance of any building
permits.
F.
The performance security shall be released by the Town Board upon
the statement of the Stormwater Management Officer that the requirements
of this chapter have been met.
G.
The Stormwater Management Officer shall not approve an SWPPP unless
and until the attorney for the Town advises that the applicant has
established a financial mechanism to ensure that any subsequent landowners
shall have the financial ability to maintain the stormwater management
facilities. Should the owner propose to transfer ownership and management
responsibility to another entity, such as a homeowners' association,
the owner must indicate how the other entity shall meet its obligation
to maintain the stormwater management facilities and how it will bear
the financial burden of meeting this obligation. The Stormwater Management
Officer may, at his discretion, require that maintenance security
in the form of an irrevocable letter of credit, cash or bank or certified
funds drawn on a national or state bank be posted to meet this obligation.
The amount of the financial security shall be equal to the estimated
cost of maintain the system for a period of five years.
[Amended 1-9-2017 by L.L. No.
1-2017]
A.
The Stormwater Management Officer shall not approve the SWPPP unless
adequate provisions have been made for inspection of the property.
The applicant shall arrange with the Stormwater Management Officer
for scheduling the following inspections:
(1)
Initial inspection prior to approval of the SWPPP, which inspection
may be waived at the discretion of the Stormwater Management Officer;
(2)
Periodic construction inspection to be made during construction of
underground drainage structures and during construction of any basin
dams;
(3)
As-built inspection to be made when all work has been completed.
B.
Although inspections will be made by the Stormwater Management Officer
or his designate, it is the responsibility of the applicant to provide
certification to the Town, in writing, with the as-built plans, that
all work has been completed in accordance with this chapter and all
applicable state and federal regulations and requirements.
C.
The applicant, owner or developer, or their representative, shall
be on site at all times during construction or grading activity and
shall document the effectiveness of all erosion and sediment control
practices. Inspection reports shall be completed every seven days.
More frequent inspection for sites that are approved to disturb greater
than five acres shall be required, as specified in the waiver for
such expanded disturbance. The reports shall be delivered to the Stormwater
Management Officer and also copied to the site logbook.
D.
The Stormwater Management Officer, or his designate, shall notify
the applicant, in writing, of any deficiencies observed during inspection.
Such notice may be made by e-mail to the e-mail address on file with
the Stormwater Management Officer and followed within one business
day by written notice sent via regular mail. Any deficiencies shall
be promptly corrected by the applicant within the time frame indicated
by the Stormwater Management Officer, or the applicant will be subject
to the violation provisions of this chapter.
A.
Any land development activity that is commenced or is conducted contrary
to this chapter may be restrained by injunction or otherwise abated
in a manner provided by law.
B.
Violations of this chapter shall be subject to the penalty, enforcement
and remedy provisions of New York Town Law § 268, and the
Building Inspector and Stormwater Management Officer are hereby jointly
and severally empowered by the Town Board with the authority to institute
any proceeding to enforce the requirements of this chapter, including,
but not limited to, the issuance of stop-work orders.
C.
If any land development activity is installed or conducted in violation
of this chapter, the Building Inspector may withhold any building
permit or certificate of occupancy until compliance has been achieved.
D.
The Stormwater Management Officer may direct any violator to restore
land to a stabilized condition. In the event that restoration is not
undertaken after notice, the Town of Cornwall may take necessary corrective
action. Before taking corrective action, the Stormwater Management
Officer shall give the violator written notice of the nature of the
existing defects, with a copy to the owner, if different. If the violator
or owner fails within 14 days from the date of notice to commence
corrective action, the Town may take necessary corrective action,
the cost of which shall become a lien on the real property until paid.
This remedy shall be in addition to the other provisions and remedies
provided in this section.