The following technical standards shall be used in the design
and installation of all erosion control, sediment control and stormwater
practices designed or installed under this chapter:
A. New York Standards and Specifications for Erosion and Sediment Control
(Empire State Chapter of the Soil and Water Conservation Society),
or the most current version or its successor (also referred to as
the "Erosion Control Manual").
B. New York State Stormwater Design Manual, latest edition (New York
State Department of Environmental Conservation), or the most current
version or its successor (also referred to as the "Erosion Control
Manual").
C. Urban Hydrology for Small Watersheds (TR55) (USDA Natural Resource
Conservation Service), or the most current version or its successor
(also referred to as the "Erosion Control Manual").
D. Soil Survey of Dutchess County, New York (USDA Natural Resource and
Conservation Service), or the most current version or its successor
(also referred to as the "Erosion Control Manual").
E. East of Hudson Phosphorus Removal Supplement for portion of the Town
of Pawling within the Croton Watershed, or the most current version
or its successor (also referred to as the "Erosion Control Manual").
F. New York State Department of Environmental Conservation SPDES General
Permit for Stormwater Discharges from Construction Activity Permit
No. GP-0-10-001, or as amended or revised, or the most current version
or its successor (also referred to as the "Erosion Control Manual").
An erosion and sediment control plan shall be prepared in accordance
with the technical standards provided for herein, and at a minimum
shall include the following information:
A. Existing features map(s), at a scale no smaller than one inch equals
100 feet, indicating:
(1) The boundaries of all parcels on which site preparation activities
are proposed to be undertaken.
(2) All public improvements within a distance of 500 feet of the parcel
on which site preparation activities are proposed to be undertaken,
the structures identified by their uses and capacities, and the roads
identified by their surface material and width of surface.
(3) All wetlands greater than 4,000 square feet in size and any watercourses
located either on the site or within a distance of 100 feet of the
parcels on which site preparation activities are proposed to be undertaken.
(4) Existing topography at contour intervals of two feet referenced to
USGS datum.
(5) All sewer, water, gas and electric lines and all other utilities
within the parcels on which site preparation activities are proposed
to be undertaken.
(6) The location and description of all vegetation located within the
area of proposed disturbance, and including the area within 100 feet
of the disturbance.
(7) The depth to bedrock on the site proposed for site preparation activities.
(8) The depth to permanent groundwater aquifers on the site proposed
for site preparation activities.
(9) The boundary of the one-hundred-year floodplain, together with wetland
boundaries.
(10)
Forested land and tree clusters within a distance of 500 feet
of the parcel on which site preparation activities are proposed to
be undertaken.
(11)
All steep slopes on the site proposed for the site preparation
and/or other disturbance.
(12)
All clearing or tree cutting, identified as to the nature of
vegetation affected.
(13)
Drainage computations to evaluate the peak rates and volumes
of runoff for the site in its predeveloped and postdeveloped conditions
if required by the Stormwater Management Officer, Planning Board or
Town Engineer.
(14)
Development standards. All development plans, specifications
and timing schedules, including extensions of previously approved
plans, shall comply with the technical standards identified herein
and shall be designed for "newly graded" or "during construction"
conditions. In the event of conflict with this chapter, the requirements
which, to the greater extent, will serve to minimize erosion shall
apply.
B. Site plan. A site plan shall be prepared at a scale no smaller than
one inch equals 50 feet, which shows the proposed developed conditions
for the site and the proposed erosion and sediment control measures,
including:
(1) The location of all excavation, filling and grading proposed to be
undertaken, identified as to the depth, volume and nature of the materials
involved.
(2) The location of all soil stripping or tree cutting, identified as
to the nature of vegetation affected.
(3) All areas where topsoil is to be removed, stockpiled and ultimately
placed.
(4) All temporary and permanent vegetation to be placed on the site,
identified as to plant type, size, quantity, location, seed mixture
and rate of application, as appropriate.
(5) The type, location and application rate of all mulch.
(6) All temporary and permanent drainage, erosion and sediment control
practices, including such practices as stormwater ponds and temporary
sediment basins, identified as to the type of facility, the materials
from which it is constructed, its specifications or manufacturer product
identification number, its dimensions and its capacity.
(7) The anticipated pattern of surface drainage during periods of peak
runoff upon completion of site preparation and construction activities,
identified as to rate and direction of flow at all major points within
the drainage systems.
(8) The location of all roads, driveways, sidewalks, structures, utilities
and other improvements, including the finished grade of any proposed
structures.
(9) The
final contours of the areas of the site affected by an action requiring
a permit in intervals of no greater than two feet.
C. Supporting calculations to demonstrate the suitability of erosion
and sediment control measures.
D. A construction schedule which is keyed to the site plan indicating:
(1) When major phases of the proposed project are to be initiated and
completed.
(2) When major site preparation activities are to be initiated and completed.
(3) When the installation of temporary and permanent vegetation and drainage,
erosion and sediment control facilities are to be completed.
(4) The anticipated duration, in days, of exposure of all major areas
of site preparation before the installation of erosion and sediment
control measures.
E. An estimate of the costs of providing temporary and permanent vegetation
and drainage, erosion and sediment control facilities prepared by
a qualified individual as contained herein.
Prior to the issuance of any approval that has a stormwater
management facility as one of the requirements, the applicant or developer
must execute a maintenance easement agreement that shall be binding
on all subsequent landowners served by the stormwater management facility.
The easement shall provide for access to the facility at reasonable
times for periodic inspection by the Town of Pawling to ensure that
the facility is maintained in proper working condition to meet design
standards and any other provisions established by this chapter. The
easement shall be recorded by the grantor in the office of the County
Clerk after approval by the Town Attorney of the Town of Pawling with
the original easement after recording to be delivered to the Pawling
Town Clerk.
As a condition of the approval of a land development permit,
the Stormwater Management Officer may require that a maintenance agreement
for the future operation and maintenance of one or more of the stormwater
management practices proposed for the site, in a form acceptable to
the Town Attorney and binding on all subsequent landowners, be executed
and recorded in the office of the County Clerk as a deed restriction
on the property.
The following notations are to be included on all subdivision
and site plan erosion and sediment control plans, and may be required
on erosion and sediment control plans prepared for major and minor
land development permits:
A. Road and drainage improvements.
(1) All topsoil to be stripped from the area being developed shall be
stockpiled not less than 200 feet from any body of surface water and
shall be immediately seeded with rye grass mixture with a quick germination
time.
(2) On all embankment fill slopes, topsoil shall be stripped at least
five feet wider than required for the embankment toe of slope. All
fill slopes shall be immediately stabilized using appropriate techniques
which meet the design criteria described in the New York Standards
and Specifications for Erosion and Sediment Control.
(3) Erosion and sediment control measures, including but not limited
to silt fencing, sediment traps and check dams, shall also be employed
where necessary for supplementary erosion control measures.
(4) All cut slopes and embankment fills are to be immediately laid back
and stabilized using appropriate techniques which meet the design
criteria described in the New York Standards and Specifications for
Erosion and Sediment Control, which may include the following:
(a)
Grade to finished slopes.
(c)
Topsoiled with not less than four inches of suitable topsoil
material.
(d)
Seeded with perennial rye grass. Seed shall be applied at the
rate of not less than five pounds per 1,000 square feet.
(e)
Mulched with not less than one inch and not more than three
inches of straw (two tons per acre) and anchored in a suitable manner.
(5) Temporary on-site sedimentation basins for the immediate control
of erosion and sediment transport are to be provided when and where
required or ordered. The length, width and depth of such basins are
to be determined in the field in accordance with the New York Standards
and Specifications for Erosion and Sediment Control or Town Engineer.
(6) All erosion control structures are to be maintained in proper functioning
order and are to be replaced or repaired as necessary.
B. General.
(1) Construction equipment shall not unnecessarily cross live streams
except by means of bridges and culverts or other approved methods.
(2) Wherever feasible, natural vegetation should be retained and protected.
(3) Only the smallest practical area of land should be exposed at any
one time during development.
(4) Erosion control requirements shall include surface stabilization
measures applied as soon as practicable in portions of the site where
construction activities have temporarily or permanently ceased, but
in no case more than seven days after the construction activity in
that portion of the site has temporarily or permanently ceased. From
November 1 through March 31, any disturbed area must be stabilized
using a heavy mulch layer, a rolled erosion control product or another
method that does not require seed germination to control erosion.
(5) The permanent final vegetation and structures shall be installed
as soon as practical and as may be directed by the Stormwater Management
Officer or Town Engineer.
(6) All erosion control measures employed during construction shall comply
with the standards found in New York Standards and Specifications
for Erosion and Sediment Control, latest edition.
(7) Phasing shall be required on all sites disturbing greater than one
acre with the size of each phase to be established by the Planning
Board or the Stormwater Management Officer.
The standards and requirements contained herein shall be applied
in reviewing and approving all permits pursuant to this chapter.
A. An erosion and sediment control plan shall seek to return the quality
of the stormwater leaving the site to its predisturbance condition
to the maximum extent practicable.
B. Excavation, filling, grading and stripping shall be permitted to
be undertaken only in such locations and in such a manner as to minimize
the potential of erosion and sediment and the threat to the health,
safety and welfare of neighboring property owners and the general
public. Alterations of grade or disturbances to the natural vegetative
cover on slopes greater than 30% shall be avoided.
C. Site preparation and construction shall be fitted to the vegetation,
topography and other natural features of the site and shall preserve
as many of these features as feasible.
D. The control of erosion and sediment shall be a continuous process
undertaken as necessary prior to, during and after site preparation
and construction.
E. The smallest practical area of land shall be exposed by site preparation
at any given time.
F. Mulching or temporary vegetation suitable to the site shall be used
where necessary to protect areas exposed by site preparation, and
permanent vegetation which is well adapted to the site shall be installed
as soon as practical.
G. Where slopes that have been exposed or regraded during site preparation
are to be revegetated, the slopes shall not be of such steepness that
vegetation cannot be readily established or that problems of erosion
or sediment may result.
H. Site preparation and construction shall not cause a permanent adverse
effect on the free flow of water by encroaching on, blocking or restricting
watercourses.
I. All fill material shall be of a composition suitable for the ultimate
use of the fill, free of rubbish and brush, stumps, tree debris, rocks,
frozen material and soft or easily compressible material.
J. Fill material shall be compacted sufficiently to prevent problems
of erosion, and where the material is to support structures, it shall
be compacted to a minimum density of 90% of modified proctor with
proper moisture control.
K. All topsoil which is excavated from a site shall be stockpiled and
used for the restoration of the site, and such stockpiles, where necessary,
shall be seeded or otherwise treated to minimize the effects of erosion.
Topsoil is not to be removed or sold from the site unless restoration
has been completed.
L. Prior to, during and after site preparation and construction, an
integrated drainage system shall be provided which at all times minimizes
erosion, sediment, hazards of slope instability and adverse effects
on neighboring property owners.
M. The natural drainage system shall generally be preserved in preference
to modifications of this system, excepting where such modifications
are necessary to reduce levels of erosion and sediment and adverse
effects on neighboring property owners.
N. All drainage systems shall be designed to handle adequately the anticipated
flows, both within the site and from the entire upstream drainage
basin, so as to achieve no net increase in peak rate of runoff from
the site.
O. Sufficient grades and drainage facilities shall be provided to prevent
the ponding of water, unless such ponding is proposed by the approved
site plan, in which event there shall be sufficient water flow to
maintain proposed water levels and to avoid stagnation.
P. There shall be provided, where necessary to minimize erosion and
sediment, such measures as benches, berms, terraces, diversions, temporary
sediment basins and retention basins. During the course of construction,
where the Stormwater Management Officer or Town Engineer determines
that additional erosion control measures are needed, they shall be
provided by the project owner at no cost to the Town of Pawling.
Q. Drainage systems, plantings and other erosion or sediment control
devices shall be maintained as frequently as necessary to provide
adequate protection against erosion and sediment and to ensure that
the free flow of water is not obstructed by the accumulation of silt,
debris or other material or by structural damage.
R. Wherever possible, clean water shall be diverted around any areas
of disturbance.
S. For any proposed grades planned to have a slope greater than 3H:1V
(three feet horizontal by one foot vertical) the design engineer shall
provide calculations documenting that the slope will be stable as
designed. Slope stability should be demonstrated by two-dimensional
limiting equilibrium methods such as the Bishop Simplified Method.
Further, the analysis should include an evaluation of seasonal high
groundwater conditions, including subsurface investigations if deemed
necessary, to assure that the slope will remain stable in "worst case"
conditions.
T. The exposure of an area by site preparation shall be kept to the
shortest practical period of time prior to the construction of structures
or improvements or the restoration of the exposed areas to an attractive
natural condition. The developer shall initiate stabilization measures
as soon as practicable in portions of the site where construction
activities have temporarily or permanently ceased, but in no case
more than seven days after the construction activity in that portion
of the site has temporarily or permanently ceased, except where the
initiation of stabilization measures by the seventh day after construction
activity temporarily or permanently ceased is precluded by snow cover
or frozen ground conditions, stabilization measures shall be initiated
as soon as practicable.
A copy of all notices of intent and all contractor's certifications,
required pursuant to the New York State General Permit for Stormwater
Discharges from Construction Activity Permit No. GP-0-10-001, as amended
or revised, for all land disturbances, development or redevelopment
located within the Town of Pawling shall also be filed with the Stormwater
Management Officer and the Pawling Planning Office, to be placed in
the applicant's file.