The developer shall erect at every street intersection a street
sign or street signs having thereon the names of the intersecting
streets and traffic control signs as specified by the Borough Engineer.
At intersections where streets cross, there shall be at least two
such street signs, and at the intersections where one street ends
or joins another street (T-intersections), there shall be at least
one such street sign. Street signs shall be of the size, design, materials
and colors required by the Borough and shall be installed prior to
the issuance of an occupancy permit for the properties which are part
of the subdivision or land development.
[Amended 5-8-2018 by Ord.
No. 387; 6-14-2022 by Ord. No. 421]
A. General.
(1) The applicant shall construct or install such drainage structures,
on site and off site, as necessary to:
(a)
Prevent erosion damage and to satisfactorily carry off or detain
and control the rate of release of surface waters.
(b)
Encourage all runoff-control measures to percolate the stormwater
into the ground to aid in the recharge of groundwater.
(c)
Carry surface water to the nearest adequate street, storm drain,
stormwater BMP, natural watercourse, or drainage facility.
(d)
Take surface water from the bottom of vertical grades, to lead
water away from springs, and to avoid excessive use of cross gutters
at street intersections and elsewhere.
(e)
Handle the anticipated peak discharge from the property being
subdivided or developed and the existing runoff being contributed
from all land at a higher elevation in the same watershed.
(f)
Maintain the adequacy of the natural stream channels. Accelerated
bank erosion shall be prevented by controlling the rate and velocity
of runoff discharge to these watercourses so as to avoid increasing
the occurrence of streambank overflow.
(g)
Preserve the adequacy of existing culverts. Bridges and similar
structures shall be preserved by suppressing the new flood peaks created
by new alteration or development of land.
(2) Drainage area boundary plans shall be submitted, reviewed, and approved
for all structures, stormwater BMPs, and collection devices.
(3) Additional studies and higher levels of control than the minimum
provided in these and other New Britain Borough requirements and criteria
may be required by the Borough Council to ensure adequate protection
to life and property.
(4) If special geological hazards or soil conditions, such as carbonate
derived soils, are identified on the site, the applicant's engineer
shall consider the effect of proposed stormwater management measures
on these conditions. In such cases, the Borough may require an in-depth
report by a qualified soils engineer.
B. Retention of existing watercourses and natural drainage features.
(1) Whenever a watercourse, stream or intermittent stream is located
within a development site, it shall remain open in its natural state
and location and shall not be piped.
(2) The existing points of natural discharge onto adjacent property shall
not be altered without the written approval by the affected landowners.
(3) No stormwater runoff or natural drainage shall be so diverted as
to overload existing drainage systems or create flooding or the need
for additional drainage structures on private properties or public
lands.
C. All subdivisions and land developments are subject, in addition, to the requirements of Chapter
375, Stormwater Management, of the Code of the Borough of New Britain, which is included in these regulations by reference.
D. Stormwater runoff which may result from alteration or development of land shall be controlled by permanent stormwater runoff BMPs that will provide the required standards within this section, Chapter
375, and any other requirements of New Britain Borough. The methods of stormwater control or best management practices (BMPs) which may be used to meet the required standards are described in this section and the Pennsylvania Department of Environmental Protection's Pennsylvania Stormwater Best Management Practices Manual, dated December 2006, as amended (PA BMP Manual). The choice of BMPs is not limited to those referenced in this section and/or the manual. Any selected BMP must meet or exceed the required standards and shall incorporate sound engineering principles and practices.
E. Design criteria for infiltration BMPs. In addition to the design
criteria and specifications in the PA BMP manual and any other design
criteria in this section, all infiltration BMPs shall meet the minimum
requirements:
(1) A detailed infiltration testing and soils evaluation of the project site shall be performed to determine the suitability of infiltration BMPs. The evaluation shall be performed by a qualified professional and, at a minimum, address soil permeability, depth to limiting zones, karst/susceptibility to sinkhole formation, and subgrade stability. Infiltration BMPs shall be selected based on the suitability of soils and site conditions and shall be constructed on soils that have the characteristics defined in §
375-303C(5) and
(6).
(2) All infiltration BMPs shall be provided with an overflow or spillway
which safely permits the passing of runoff greater than that occurring
during the largest design storm. The overflow or spillway shall be
set above the maximum proposed ponding depth.
(3) The infiltration BMP shall be positive overflow controls to prevent
storage within one foot of the finished surface above the facility.
(4) Infiltration BMPs shall have a bottom slope of no greater than 1%
but shall preferably have a level bottom.
F. Design criteria for bioretention facilities. Bioretention facilities
BMPs, including rain gardens, shall be designed in accordance with
the design criteria and specifications in the PA BMP Manual and shall
meet the following the minimum requirements:
(1) All concentrated discharges directed to a bioretention facility shall
be conveyed through a pretreatment filter strip. The filter strip
shall be designed to reduce the incoming velocities and to filter
out coarser sediment particles. Examples of pretreatment filter strips
include sand or gravel diaphragms, grass swales, sand filters, stone
check dams, etc.
(2) A minimum planting soil bed depth of two feet for herbaceous plants
and three feet for trees and shrubs shall be provided. Planting soil
shall be a loam soil capable of supporting healthy vegetative cover.
(3) All bioretention facilities shall incorporate an organic mulch layer.
The organic mulch layer shall be standard landscape style, single
or double, shredded hardwood mulch or chips. The mulch layer shall
be well-aged, uniform in color, and free of other materials such as
weed seed, soil roots, etc. The mulch layer shall be applied to maximum
depth of three inches. Grass clippings shall not be used as mulch
material.
(4) All bioretention facilities shall incorporate native landscaping.
Plant species shall be selected based on the ability to tolerate stresses
such as pollutants, variable soil moisture, and ponding fluctuations.
A mixture of trees, shrubs, and/or herbaceous plant species shall
be selected to ensure diversity.
(5) The maximum side slopes of bioretention BMPs shall be four horizontal
to one vertical.
(6) A minimum grade of 2% shall be maintained for areas of sheet flow.
For channel flow, a minimum grade of 1% shall be maintained. For bioretention
facilities relying on infiltration for drainage, rather than sheet
or channel flow, a level bottom is permitted.
(7) Bioretention facilities with an aboveground ponding depth of greater than 2.5 feet during any post-development design storm shall be designed in accordance with the requirements of §
385-34G.
G. Design criteria for aboveground basins. Aboveground basin BMPs shall
be designed in accordance with the design criteria and specifications
in the PA BMP manual and shall meet the following the minimum requirements:
(1) Unless permitted as a special exception by the Zoning Hearing Board,
basins shall not be located within floodplains nor within areas of
floodplain soils, with the exception that areas of alluvial soils
may be utilized if proof is provided by the applicant and accepted
by the Borough Council that the area is not subject to flooding.
(2) Basins shall be designed to facilitate regular maintenance, mowing,
and periodic desilting and reseeding.
(3) Whenever possible, the side slopes and basin shape shall conform
to the natural topography. When such design is impractical, the construction
of the basin shall utilize slopes as flat as possible to blend the
structure into the terrain. The maximum slope of the earthen basin
embankments shall be four horizontal to one vertical.
(4) In order to ensure proper drainage to the basin bottom, a minimum
grade of 2% shall be maintained for areas of sheet flow. For channel
flow, a minimum grade of 1% shall be maintained. For basins relying
on infiltration for drainage, rather than sheet or channel flow, a
level bottom is permitted.
(5) The top or toe of any slope shall be located a minimum of five feet
from any property line.
(6) The minimum top width of the detention basin berm shall be 10 feet.
(7) If permanent ponds are used, the applicant shall demonstrate that
such ponds are designed to protect the public health and safety.
(8) A cutoff trench shall be provided along the center line of any dam
or earth fill embankments. The trench shall have a bottom width of
not less than four feet, but adequate to allow use of equipment necessary
to obtain proper compaction. Side slopes of cutoff trench shall be
no steeper than 1:1 ratio. The trench shall be filled with successive
thin layers of relatively impervious material, each layer being thoroughly
compacted.
(9) All basin embankments shall be placed in lifts not to exceed eight
inches in thickness and each lift shall be compacted to a minimum
of 95% of modified proctor density as established by ASTM D-1557.
Prior to proceeding to the next lift, the compaction shall be checked
by a soils engineer employed by the applicant. Compaction tests shall
be run on the leading and trailing edge of the berm along with the
top of the berm. Verification of required compaction shall be submitted
to the Borough prior to utilization of any basin for stormwater management.
(10)
All aboveground basins shall be provided with a primary spillway/outlet
pipe meeting the following the minimum requirements:
(a)
The sizing of the outlet pipe shall be based on the post-construction
100-year storm without utilizing the emergency spillway.
(b)
All outlet pipes through the basin berm shall be reinforced
concrete pipe with watertight joints.
(c)
The pipe barrel and riser shall be placed on a firm foundation.
The fill material around the primary spillway shall be placed in four-inch
lifts and compacted to at least the same density as the adjacent embankment.
(d)
Anti-seep collars shall be installed around the pipe barrel
within the normal saturation zone of the basin berms and shall be
poured in place.
[1]
The anti-seep collars and their connections to the pipe barrel
shall be watertight.
[2]
The anti-seep collars shall extend a minimum of two feet beyond
the outside of the principal pipe barrel.
[3]
The maximum spacing between the collars shall be 14 times the
minimum projection of the collar measured perpendicular to the pipe.
[4]
A minimum of two anti-seep collars shall be installed on each
outlet pipe.
(e)
All outlet pipes shall have endwalls and energy-dissipating
devices (riprap, end sills, etc.) designed in accordance with the
Pennsylvania Department of Environmental Protection's Erosion
and Sediment Pollution Control Program Manual No. 363-2134-008, as
amended and updated (PA E&S Manual).
(11)
All aboveground basins shall be provided with an emergency spillway
meeting the following the minimum requirements:
(a)
Whenever possible, the emergency spillway shall be constructed
on undisturbed ground.
(b)
Emergency spillways constructed on undisturbed ground may be
constructed of reinforced vegetated earth. All other spillways shall
be constructed of riprap, concrete checkerblocks, or similar materials
approved by the Borough Engineer.
(c)
All emergency spillways shall be constructed so that the basin
berm is protected against erosion.
(d)
The emergency spillway shall not discharge over earthen fill
and/or easily eroded material.
(e)
The construction material of the emergency spillways shall extend
along the upstream and downstream berm embankment slopes. The upstream
edge of the emergency spillway shall be a minimum of three feet below
the spillway crest elevation. The downstream slope of the spillway
shall, at a minimum, extend to the toe of the berm embankment.
(f)
The minimum capacity of all emergency spillways shall be the
peak flow rate from the post-development 100-year design storm.
(g)
The minimum freeboard through the emergency spillway shall be
one foot. Freeboard is defined as the difference between the design
flow elevation through the spillway and the elevation of the top of
the settled basin berm. Six inches, minimum, is required between the
100-year water surface elevation and the emergency spillway crest.
(12)
Sediment basins and sediment traps for sediment control during
construction shall be designed in accordance with the PA E&S Manual.
H. All other stormwater management BMPs shall be designed in accordance
with the design criteria and specifications in the PA BMP Manual and
shall incorporate sound engineering principles and practices.
I. Design criteria for drainage channels and swales.
(1) All drainage channels and swales shall be designed to carry the peak
flow from a twenty-five-year storm with a minimum of six inches of
freeboard. Provisions shall be made to ensure that larger runoff events
do not impair public safety or cause damage to adjacent lands or public
property.
(2) All drainage channels and swales shall be designed to prevent erosion
of the bed and banks and suitable stabilization shall be provided
to prevent erosion. The maximum permissible flow velocity shall not
exceed those outlined in Table 6.4 Maximum Permissible Velocities
(ft/sec) of Channels Lined with Vegetation and its additional notes
of the PA E&S Manual.
(3) Vegetated drainage channels shall have a maximum grade of three horizontal
to one vertical on those areas to be mowed.
(4) Swales shall be designed to prevent the passage of water onto the
cartway during a twenty-five-year frequency storm of five-minute duration.
J. Design criteria for storm drain pipes, inlets, and manholes.
(1) Storm sewers, culverts, and related installations shall be provided:
(a)
To permit the unimpeded flow of natural watercourses in such
a manner as to protect the natural character of said watercourses
and to provide regulated discharge.
(b)
To ensure adequate drainage of all low points.
(c)
To intercept stormwater runoff along streets at intervals reasonably
related to the extent and grade of the area of drainage and to prevent
substantial flow of water across intersections.
(2) The design discharge for use in determining gutter flow, spacing
of inlets, and for pipe sizing of storm sewer shall be computed by
the rational formula Q = CIA, in which Q equal discharge, cubic feet
per second; C equal runoff coefficient; I equal rainfall intensity,
inches per hour; A equal area, acres.
(a)
The storm drainage system shall be designed to carry runoff
from the twenty-five-year storm based on rainfall intensities from
the latest version of the NOAA Atlas 14 rain data corresponding to
the Doylestown rain gage. This data may also be directly retrieved
from the NOAA Atlas 14 website: hdsc.nws.noaa.gov/hdsc/pfds/orb/pa_pfds.html.
(b)
In all cases where storm drainage is picked up by means of a
headwall or inlet structure and hydraulic inlet or outlet conditions
control, the pipe shall be designed as a culvert for a fifty-year
storm.
(c)
The elevation of the hydraulic gradient at any point in the
storm sewer system shall be below of the surface of the ground based
on the 100-year storm rainfall intensities from the latest version
of the NOAA Atlas 14 rain data corresponding to the Doylestown rain
gage.
(d)
The runoff factors set forth in Table B-7 in Appendix B of the
New Britain Borough Stormwater Management Ordinance shall be utilized.
(e)
A minimum five-minute storm duration shall be used. Where supported
by the drainage area and related plans and calculations, longer storm
durations shall be utilized, using the time-of-concentration approach
to adjust the time of concentration.
(f)
Design shall be based on gravity (non-pressure) flow.
(3) Storm sewer pipes.
(a)
All storm sewer pipes shall be reinforced concrete pipe, smooth
lined high-density polyethylene, or other pipe material as may be
approved by the Borough Engineer.
(b)
The Manning's roughness coefficients ('n') set
forth in Table B-8 in Appendix B of the New Britain Borough Stormwater
Management Ordinance shall be utilized.
(c)
The minimum diameter of all storm drainage pipe shall be 15
inches or an equivalent thereto. Where pipe cover is restricted, equivalent
pipe arches may be used in lieu of circular pipe.
(d)
The minimum slope of any pipe shall be 0.5%.
(e)
The top of storm drainage pipes beneath cartways shall be at
least six inches below subgrade elevation. Outside of paved areas,
all pipes shall have a minimum cover of two feet.
(f)
Storm sewers shall be placed within a street right-of-way, parallel
to the cartway. When located outside of a right-of-way, storm sewers
shall be placed and centered within an easement having a width of
not less than 20 feet.
(4) Inlets and manholes.
(a)
Abrupt changes in direction or slope of storm drainage pipe
shall be avoided. Where there is a such a deflection in the storm
pipe system, an inlet or manhole shall be placed at the point of change.
(b)
An inlet or manhole shall be provided at all changes of grade,
at all locations where a transition in storm sewer pipe size is required,
and at all points of convergence of two or more influent storm sewer
pipes.
(c)
The spacing on inlets and manholes shall not exceed a maximum
distance of 450 feet along any one continuous line.
(d)
Inlets, manholes, and related tops, covers, and frames shall
conform to Pennsylvania Department of Transportation specifications.
(e)
All inlets must be designed to accommodate the twenty-five-year
peak flow rate. The capacity of all C-, M-, or S-type inlets shall
be determined from the Pennsylvania Department of Transportation Design
Manual, Part 2, and any amendments.
(f)
Spread of runoff in gutters shall not exceed eight feet in width
or 1/2 of the travel lane, whichever is lesser, during a ten-year
storm event.
(g)
At street intersections, inlets shall be placed in the tangent
portion rather than the curved portion of the curbing.
(5) Shoulders in cut areas (without swales).
(a)
Water flowing in the shoulder shall not encroach more than 2/3
the shoulder width during a twenty-five-year frequency storm of five-minute
duration.
(b)
The maximum velocity, as determined by Manning's Equation,
shall not exceed the allowable velocities in outlined in Table 6.4
Maximum Permissible Velocities (ft/sec) of Channels Lined with Vegetation
and its additional notes of the PA E&S Manual for the specific
type of shoulder material.
(c)
Inlets shall be provided to control the shoulder encroachment
and water velocity.
(6) Curbed sections.
(a)
The maximum encroachment of water on the cartway shall not exceed
two inches in depth at the curb during a twenty-five-year frequency
storm of five-minute duration.
(b)
Inlets shall be provided to control the encroachment of water
on the cartway.
[Amended 9-13-2016 by Ord. No. 377]
A. These regulations are promulgated in an effort to insure that each
dwelling unit or commercial, industrial, educational, institutional
or office building, hereafter constructed within the Borough, will
have an adequate supply of potable water. A hydrogeological study
for all potential public water systems shall be submitted with all
applications for subdivision or land development.
B. Connection to the public water system shall be required for the following
uses:
(1) Five or more single-family detached dwellings.
(2) All multifamily developments.
(3) Mobile or manufactured home parks.
(7) Educational/institutional uses, including hospitals, schools, and
nursing home or personal care facilities.
C. The developer shall construct water mains in such a manner as to
make adequate water service available to each lot or dwelling unit
within the subdivision or land development and shall extend the water
mains to the perimeter of the property at a public street and shall
terminate the water main in an accessible gate valve. The water supply
must comply with the regulations and standards of the Pennsylvania
Department of Environmental Protection, with the construction standards
of the authority managing or maintaining the public water system,
and with the regulations of the Borough.
D. The public water system shall be designed with adequate capacity,
storage facility, and appropriately spaced fire hydrants, for firefighting
purposes. All public water systems shall be approved by the Borough
Engineer, applicable water authority, and the Borough Fire Marshal.
E. All public water systems shall be offered for dedication to the applicable
water authority. The water authority shall be under no obligation
to accept dedication.
F. Applicants for subdivision and land development shall present evidence
to Borough Council that the subdivision or land development is to
be supplied by a certified public utility, or a municipal corporation,
authority or utility. A copy of a certificate of public convenience
from the Pennsylvania Public Utility Commission, or an application
for such certification, or a commitment or agreement to serve the
property in question, whichever is appropriate, shall be acceptable
evidence.