[Amended 1-21-1992 by Ord. No. 295]
A.
The purpose of this article is to establish and define
the public improvements which will be required to be constructed by
the applicant as a condition for final plan approval.
B.
All construction shall be completed in accordance
with the specific conditions, drawings and specifications approved
by the Board.
[Amended 1-21-1992 by Ord. No. 295]
A.
The improvements included in this article are minimum
requirements. However, the Board of Supervisors reserves the right
in any case to increase the same if conditions so warrant.
B.
If any mandatory provisions of this chapter are shown
by the applicant to be unreasonable and to cause undue hardship as
they apply to his proposed subdivision or land development, the Board
of Supervisors may grant a modification to such applicant from such
mandatory provisions, so that substantial justice may be done and
the public interest secured; provided that such modifications will
not have the effect of nullifying the intent and purpose of this chapter.
C.
In granting modifications, the township may impose
such conditions as will, in its judgment, secure substantially the
objectives of the standards or requirements so varied or modified.
When changes from the accepted drawings and
specifications become necessary during construction, written acceptance
by the Board of Supervisors with the advice of the Township Engineer
shall be secured before the execution of such changes.
Adequate provisions for the satisfactory maintenance
of all streets shall be made by dedication to and acceptance for maintenance
by the township, or by other acceptable means.
[Amended 1-21-1992 by Ord. No. 295]
A.
The construction of streets, roads, lanes and driveways,
as shown upon the approved final plans, shall conform to the requirements
of the Pennsylvania Department of Transportation, Form 408, or latest
edition thereof, specifications.
A.
The owner shall erect at every street intersection
a street sign or street signs having thereon the names of the intersecting
streets. At intersections where streets cross, there shall be at least
two such street signs; and at intersections where one street ends
or joins with another street, there shall be at least one such street
sign.
[Amended 1-21-1992 by Ord. No. 295]
The owner shall install or cause to be installed,
at the owner's expense, streetlights serviced by underground conduit
in accordance with a plan approved by the Township Streetlight Engineer
in conformity to a general standard of streetlighting established
by the Board of Supervisors. Provision shall be made for energizing
said lighting after 50% or more of the dwellings in a given subdivision
or land development or section of a subdivision or land development
have been occupied. The owner shall be responsible for all costs involved
in lighting the streets until such time that the streets are accepted
or condemned as public streets by the Board of Supervisors.
A.
Monuments shall be placed at each change in direction
of boundary: two to be placed at each street intersection and one
on one side of each street at angle points and at the beginning and
end of curves; utility easements shall be monumented at their beginning
and at their end, and areas to be conveyed for public use shall be
fully monumented at their external boundaries.
B.
Monuments shall be placed in the ground after final
grading is completed, at a time specified by the Township Engineer.
The monument shall be concrete, the size and length as may be approved
by the Township Engineer.
C.
All monuments shall be checked for accuracy by the
Township Engineer or their accuracy certified by the owner's engineer.
Accuracy of monument shall be within 3/100 of a foot.
[Amended 1-21-1992 by Ord. No. 295]
A.
Sidewalks shall be constructed on one side of all
frontage streets and both sides of all other streets within the subdivision
or land development, unless in the opinion of the Board of Supervisors
with the advice of the Planning Commission they are unnecessary for
public safety and convenience.
[Amended 1-21-1992 by Ord. No. 295]
A.
Curbs shall be provided along both sides of all streets,
unless in the opinion of the Board of Supervisors with the advice
of the Township Engineer they are unnecessary.
B.
Along the existing street on which a subdivision or land development abuts (hereinafter called boundary streets), curbs shall be constructed and the existing paved cartway shall be widened to the curb. The location of curbing along a boundary street shall be determined by the width of the existing or future right-of-way of the road as established by the Board of Supervisors and in accordance with those standards specified in § 160-34 of this chapter.
C.
All curbs shall be constructed in accordance with
the Pennsylvania Department of Transportation Form 408, or latest
edition thereof, specifications.
[Amended 12-1-1987 by Ord. No. 249; 1-21-1992 by Ord. No.
295; 8-17-1993 by Ord. No. 304(A); 9-7-1999 by Ord. No.
338]
This section regulates the stormwater runoff
associated with land development, land redevelopment, subdivision
of land and construction of impervious surfaces; diversion of natural
or man-made channels; and the installation of stormwater systems,
in all portions of Upper Southampton Township.
A.
Findings. The Board of Supervisors finds that inadequate
management of stormwater runoff from development and redevelopment
in a watershed increases flood flows and velocities, erodes and/or
silt stream channels, pollutes water, overloads existing drainage
facilities, undermines floodplain management in downstream communities,
reduces groundwater recharge and threatens public health and safety.
B.
Purpose. The stormwater management requirements of this section promote the public health, safety and welfare for all the areas in Upper Southampton Township by minimizing the damages described in Subsection A by provisions designed to:
(1)
Manage stormwater created by development activities,
taking into account the accumulative basin wide stormwater impacts
from peak runoff rates and runoff volumes.
(2)
Maintain and/or improve existing water quality of
streams, watercourses and impoundments by preventing the additional
loading of area stormwater runoff pollutants into the stream system
and enhancing base flow as much as possible.
(3)
Maximize perpetual groundwater recharge throughout
the watershed in an attempt to maintain existing hydrologic regime.
(4)
Preserve existing natural drainageways and watercourses.
(5)
Provide for proper maintenance of all stormwater management
facilities.
C.
Applicability.
(1)
This section shall apply to all areas of the township
including areas both inside and outside of Neshaminy Creek Drainage
Basin. This section contains those stormwater runoff control criteria
and standards which are necessary or desirable from a total watershed
perspective.
(2)
The following activities are defined as regulated
activities and shall be regulated by this section:
(a)
Land development.
(b)
Land redevelopment.
(c)
Subdivision.
(d)
Construction of new or additional impervious
surfaces (driveways, parking lots, etc.).
(e)
Construction of new building or additions to
existing building.
(f)
Diversion or piping of any natural or man-made
stream channel.
(g)
Installation of stormwater systems or appurtenances
thereto.
(h)
Construction of infiltration BMPs for single-family
residences.
(3)
This section shall apply to all regulated activities
detailed above. The more stringent requirements of any ordinance or
other requirements of Upper Southampton Township shall apply if any
regulated activity requires compliance with other ordinances and regulations
of Upper Southampton Township.
D.
Stormwater management requirements.
(1)
General requirements. For any of the regulated activities
of this section prior to preliminary and final approval of subdivision
and/or land development plans, where the issuance of any permit, or
the commencement of any land disturbance activity, the owner or developer
shall submit a stormwater management plan for approval by the Board
of Supervisors. In addition to the requirements of this section, the
plan shall meet the requirements of Title 25, Rules and Regulations
of the Pennsylvania Department of Environmental Protection, Chapter
102 (Erosion Control), Chapter 105 (Safety and Waterway Management),
Chapter 106 (Floodplain Management), and all other applicable governmental
regulations.
(2)
Stormwater management. The owner and developer shall
construct stormwater drainage facilities, including curbs, catch basins
and inlets for storm sewers, road ditches and open channels in order
to prevent erosion, flooding and other hazards to life and property.
All such facilities shall be of adequate size and grade to hydraulically
accommodate maximum potential volumes of flow. Size, type and installation
of all stormwater drains and sewers shall be constructed in accordance
with the Plans and Standards Specifications of Pennsylvania Department
of Transportation Form 408, or latest edition thereof, specifications.
(a)
The owner and developer shall construct and/or
install such drainage structures necessary to:
[1]
Prevent erosion damage to satisfactorily carry
off and detain and control rate of release of surface waters.
[2]
Encourage all runoff control measures to percolate
the stormwater into the ground to aid the recharge of groundwaters.
[3]
Direct surface water to the nearest adequate
street storm drain, detention basin, natural watercourse or drainage
facility.
[4]
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.
[5]
Safely convey and release the anticipated peak
discharge from the property being subdivided or developed, and the
existing runoff being contributed from all lands in a higher elevation
in the same watershed.
[6]
Maintain the adequacies of natural stream channels.
Accelerated bank erosion shall be prevented by controlling the rate
of velocity of runoff discharge to these waters, so as to avoid increasing
occurrence of stream bank overflow.
[7]
Reserve the adequacy of existing culverts and
bridges by suppressing the new flood peaks created by new land development
or redevelopment.
[8]
If, in the opinion of the Township Engineer,
off-site stormwater management improvements are necessary to safely
convey and release the stormwater from the proposed development, the
developer shall be responsible for the construction of all off-site
stormwater management improvements including obtaining any access
easements and/or temporary or permanent construction easements.
[9]
Off-site improvements. Any increase in runoff
may require necessary corrective measures, including deeds of easement,
deemed appropriate by the Board of Supervisors to alleviate any off-site
drainage problem affected by this subdivision, land development or
redevelopment. The cost of such measures will be borne entirely by
the owner and developer. These measures include material, installation,
costs and acquiring either temporary or permanent easements.
(b)
Retention of existing watercourses and natural
drainage features.
[1]
Whenever a watercourse, stream or intermittent
strewn 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 drainage discharge
onto adjacent properties shall not be altered without written approval
of the affected landowners and the Township Engineer. A drainage easement
of sufficient size may be required for any such discharge onto the
property of others.
[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 other private
properties or public lands.
(c)
Requirements for drainage structures and/or
pipes.
[1]
Drainage easements. Drainage easements shall
be provided to accommodate all storm drainage requirements and shall
be a minimum of 20 feet in width.
[2]
Design criteria, stormwater collection and pipe
system.
[a]
Storm sewers, culverts and related
installations shall be provided to:
[i]
Permit the unimpeded flow of natural
watercourses in such a manner as to protect the natural characteristic
of said watercourses and to provide regulated discharge.
[ii]
Ensure adequate drainage at all
low points along the street.
[iii]
Intercept stormwater runoff along
streets and intervals reasonably related to the extent and grade of
the area drainage and to prevent substantial flow of water across
intersections.
[b]
The design discharge from drainage
areas contributing to the system may be determined using the rational
equation (Q = CIA) when the total drainage does not exceed 100 acres.
[i]
The following runoff factor shall
be utilized for the rational equation.
|
Description of Area
|
Runoff Coefficient (C)
| |
|---|---|---|
|
Residential - 2-acre single- family detached
lots
|
0.40
| |
|
1-acre single-family detached lots
|
0.46
| |
|
1/2-acre single-family detached lots
|
0.50
| |
|
1/4-acre single-family detached lots
|
0.56
| |
|
2-family and multifamily
|
0.70
| |
|
Commercial
|
0.75
| |
|
Industrial
|
0.80
| |
|
Parks and cemeteries
|
0.38
| |
|
Unimproved
|
0.35
| |
|
Where the table above is not applicable, the
following factors may be used:
| ||
|
Roof tops and all impervious surfaces
|
0.90
| |
|
All other surfaces except forests
|
0.40
| |
|
Forests
|
0.30
| |
[ii]
The intensity/duration/frequency
curve for Region 5 in the latest Pennsylvania Department of Transportation
Design Manual shall be used to compute the rainfall intensity.
[iv]
Storm duration.
[A]
A five-minute storm duration shall
be used if this duration does not result in a maximum expected discharge
that exceeds the capacity of a thirty-inch pipe.
[B]
If a five-minute storm duration
results in a pipe size exceeding 30 inches, the "time and concentration"
approach shall be used in determining storm duration.
[C]
If a five-minute storm duration
results in a pipe size exceeding 30 inches, within any pipe run, the
time and concentration approach shall be used for sizing pipe from
that point on by adjusting the time and concentration.
[c]
Pipes.
[i]
Pipes shall be sized by use of
Manning's Equation with the pipes flowing full. The design shall be
based on gravity flow and not pressure flow.
[ii]
The roughness coefficient (n)
shall be in compliance with Table 2.10.5.1 roughness coefficient (n)
for Manning's Equation found in PennDOT's "Design Manual Part 2, Highway
Design."
[iii]
The minimum diameter of all storm
drainage pipes shall be 18 inches or an equivalent thereto. Where
headroom is restricted, equivalent pipe arches or elliptical may be
used in lieu of circular pipe.
[iv]
Incremental size changes to storm
drain pipes shall be 6 inches in diameter.
[v]
Abrupt changes in direction or
slope of drainage pipe shall be avoided. Where such abrupt changes
are required, the inlet or manhole shall be placed at the point of
change.
[vi]
Minimal grade of piping shall
provide a minimum velocity of 2.5 feet per second and shall have a
minimum slope of 0.5%.
[vii]
The top of storm drainage pipes
beneath cartways shall be at least six inches below subgrade elevation.
Outside of cartways, all pipes shall have a minimal cover of two feet.
[d]
Manholes.
[i]
Manholes shall neither be more
than 300 feet apart on sizes up to 24 inches nor more than 450 feet
apart on greater sizes.
[ii]
Inlets may be substituted for
manholes, on the approval of the Township Engineer at the same spacing
as required for manholes.
[iii]
Manhole covers, frames, bases
and cone sections shall conform to Pennsylvania Department of Transportation
specifications. Manhole covers shall have the word "STORM" on the
cover in two-inch-high letters.
[e]
Inlets.
[i]
At the street intersections, inlets
shall be placed in the tangent portion rather than the curve portion
of the curbing.
[ii]
Where there is a change in pipe
size in an inlet, an elevation for the top of the pipes shall be the
same or the smaller pipe shall be higher. A minimum drop of two inches
shall be provided in the inlet between the lowest inlet pipe invert
elevation and the outlet pipe invert elevation.
[iii]
If the capacity of the shoulder,
swale, curb section or depressed median section exceeds the assumed
wet capacities, the inlet capacities shall govern the spacing of inlets.
[iv]
If the capacity of the shoulder,
swale, curb section or depressed median section is less than the inlet
capacities, then the shoulder, swale, curb section or depressed section
capacity shall govern the spacing of inlets.
[v]
Type C inlets.
[A]
Type C inlets shall be installed
unmountable curbs.
[B]
In order to achieve greater efficiency,
Type C inlets shall be spaced so as to permit 51/6 of the gutter flow
to bypass the inlet.
[C]
The capacity of a Type C inlet
at a low point of a street's vertical curve may be designed to accept
four cubic feet per second (cfs) from each direction or a maximum
of eight cfs.
[vi]
Type M and Type S inlets.
[A]
Type S inlets shall be installed
in shoulder swale areas with back slopes of six horizontal to one
vertical and steeper.
[B]
Type M inlets shall be installed
in swale areas where the back slope is flatter than six horizontal
to one vertical.
[C]
Inlet capacities shall be based
on Table 2, Type M and S inlet capacities (in swale):
|
Table 2
Type M or S Inlet Capacities (in Swale)
Back Slope
| |||||
|---|---|---|---|---|---|
|
Grade
|
2:1
|
4:1
|
6:1
|
12:1
|
Dike
|
|
1.0
|
3.2
|
3.6
|
3.9
|
4.1
|
9.1
|
|
2.0
|
3.5
|
3.5
|
3.5
|
3.7
|
9.3
|
|
3.0
|
2.5
|
2.8
|
3.5
|
3.5
|
7.4
|
|
4.0
|
1.6
|
2.0
|
3.4
|
3.2
|
6.4
|
|
5.0
|
1.6
|
2.0
|
3.5
|
3.0
|
6.3
|
|
6.0
|
1.6
|
2.0
|
3.3
|
2.8
|
6.1
|
|
7.0
|
1.5
|
2.0
|
3.0
|
2.6
|
6.0
|
|
8.0
|
1.5
|
2.0
|
2.8
|
2.4
|
5.8
|
[D]
Where a drainage dike is used,
the side slope of the dike shall be eight horizontal to one vertical
or flatter.
[E]
The capacity of an inlet at a low
point in a swale (sump condition) shall be 16 cfs maximum.
[vii]
Inlets shall conform to Pennsylvania
Department of Transportation specifications, with the exception that
the use of red brick for inlet construction is not permitted.
[viii]
Shoulders in cut areas (without
swales).
[A]
Water flowing in the shoulder shall
not encroach more than 2/3 the shoulder width during a ten-year-frequency
storm of five-minute duration.
[B]
The maximum velocity, as determined
by Manning's Equation, shall not exceed the allowable velocities in
the Bucks County Erosion & Sediment Control Handbook for that
specific type of shoulder material.
[C]
Inlets shall be provided to control
the shoulder encroachment and water velocity.
[ix]
Swales adjacent to shoulders.
[A]
Swales in cut areas shall be designed
to prevent the passage of water onto the cartway during a ten-year--frequency
storm of five-minute duration.
[B]
The maximum velocity, as determined
by Manning's Equation, shall not exceed the allowable velocities in
the Bucks County Erosion & Sediment Control Handbook for the specific
type of shoulder material.
(d)
Requirement for stormwater detention.
[1]
Total watershed evaluation for future use of
undeveloped areas upstream, as shown on the approved Township Comprehensive
Plan, shall be taken into account in the design of all stormwater
management facilities. The capacity and the maximum anticipated present
flow of the body or system receiving the proposed system(s) discharge
shall be calculated to verify its compatibility of receiving any additional
flow caused by the development or subdivision. The runoff from any
proposed development or redevelopment shall be subject to an evaluation
which includes the anticipated runoff from other existing or proposed
developments within the watershed. Stormwater management facilities
designed to serve more than one property or development within the
same watershed are encouraged. Consultation with the township and
Township Engineer is required prior to the design of such facility.
[2]
The design of stormwater detention areas shall
be based upon the criteria set forth in the latest addition of Urban
Hydrology for Small Watersheds Technical Release 55 and National Engineering
Handbook, Subsection Four, Hydrology, as Published by the U.S. Department
of Agriculture, Soil Conservation Service.
[3]
Detention areas shall be designed so that the
rate of runoff from the site, when developed or redeveloped, will
neither exceed or decrease the runoff from the site that existed before
any development or redevelopment took place except where, in the judgment
of the Township Engineer, the quantity or volume of water will cause
detrimental downstream impact, quantity or volume shall be considered
in the method for stormwater regulations. This standard shall be maintained
for all storms, i.e., both high-frequency and low-frequency.
[4]
Discharge piping from the detention area shall be designed to control the rate of runoff as referred in Subsection D(2)(d)[3] above for the one- through one-hundred-year-frequency, twenty-four-hour storm.
[5]
If permanent ponds are used, the developer shall
demonstrate that such ponds are designed to protect the public health
and safety.
[6]
All facilities containing or using a permanent
pool shall have an aquatic bench that extends at least 10 feet from
the berm to prevent accidental entrance into deep water areas.
[7]
Prior to granting final approval of any subdivision
or land development plan, the township must be satisfied through contractual
arrangements that all stormwater facilities will be properly maintained.
If all or portion of the facilities are on property which will be
conveyed to an individual, homeowners' association or any other eventual
owner, guarantee must be provided to ensure maintenance will be the
responsibility of the new owners.
[8]
Detention basin maintenance fund. If the Board
of Supervisors deems it to be in the public interest to accept dedicated
land for detention, drainage detention or retention purposes, such
acceptance shall be adopted by a resolution of the Board of Supervisors
and acceptance of a deed of dedication from the developer, in addition
thereto the developer shall contribute to the township the sum of
$3500 per acre of the dedicated land or an amount as amended by alter
resolution by the Board of Supervisors. These fees shall be used by
the township to maintain land and basins dedicated. The fees shall
be paid upon acceptance of deed of dedication.
[9]
If the land of the proposed subdivision or land
development will be conveyed to two or more separate owners, the developer
shall provide written assurance and deed restrictions to the township
that the detention basins will be properly maintained by the owners
or, if accepted by the township, be dedicated to the township which
shall then be responsible for maintaining the detention basins. In
any case, the developer shall provide both short- and long-term maintenance
requirements and schedules to the entity responsible for maintenance.
In cases where the township does not accept the detention basin, then
the township reserves the right to inspect the basin to assure that
it is operating and is being properly maintained.
[10]
Underdrains. All building foundations,
grades, slabs and cellar floors located in soils that have a community
development limitation degree of moderate to severe high water table
as defined by on-site soil test witnessed by a Township Engineer,
shall be provided with an underdrain system. This underdrain system
shall provide for drainage of the enclosed volume above the slab and
relief of subsurface water to a depth not less than six inches below
the slab or foundation bottom. The system shall consist of appropriate
pipe field of a herringbone of grid iron configuration in coarse,
gravel filled trenches that in direct contact with the slab for foundation
subbase. The excavation shall provide a minimum of 0.5% slope to the
gravel filled trenches.
[11]
Stormwater management plan. A
stormwater management plan for the proposed subdivision, land development
or redevelopment shall contain the following:
[a]
Mapping of the watershed area or
areas which the proposed subdivision or land development is located.
"USC & GC Quadrangle Map or Similar."
[b]
A study shall be performed on the
watershed in which this subdivision, land development or redevelopment
is located to assess the impact the proposal will have on downstream
conditions. The stormwater management plan shall address all identified
impacts to the satisfaction of the township.
[c]
Computations for stormwater runoff
for all points of runoff concentration before, during and after development,
including all supporting data.
[d]
Complete drainage systems for the
subdivisions or land development, all existing drainage features which
are to be incorporated into the design shall be so identified with
an explanation of the operation of the facility.
[e]
Plans showing all existing/proposed
drainage facilities affecting the subject property.
[f]
A plan of the proposed stormwater
drainage system including storm drain pipes I and inlets, runoff control
devices and drainage channels.
[g]
Plan of the proposed grading.
[h]
A stage/storage curve for such
detention/retention basins.
[i]
Design computations for the sizing
of the pipe barrel and perforated riser.
[j]
Flood routing or storage requirement
calculations.
[k]
A plan showing a berm embankment
and outlet structure. The plan shall also indicate the top of berm
elevation, top width of the berm and side slopes, emergency spillway
elevation, elevations of outlet structures including the riser, dimensioning
and spacing of anti-seep collars.
[l]
A detail plan of trash racks in
a vortex device.
[m]
Overall plan of the basin area
at a scale of one inch equals 50 feet minimum showing the grading
and landscaping.
[n]
Detail plan of all required off-site
improvements.
[o]
The design computations for stormwater
drainage systems including stormwater drainage pipes and inlets, runoff
control measures, culverts and drainage channels.
[p]
A plan of erosion sediment procedures
to be utilized.
[q]
Subdivision, land development and/or
redevelopment affecting the Neshaminy Creek Watershed is subject to
additional provisions contained in Ordinance No. 303A, adopted August
17, 1993.
(e)
Detention basin design criteria.
[1]
All plans and designs for a stormwater management
facility shall determine stormwater peak discharge and runoff by use
of Soil Cover Complex Method as set forth in the latest edition of
"Urban Hydrology for Small Watersheds, Technical Release 55 and The
National Engineering Handbook of Hydrology as published by the U.S.
Department of Agriculture, Soil Conservation Service."
[2]
The following rate for all intensities shall
be used for the 24 hours, Type II distribution storm with average
antecedent moisture conditions for the frequency shown:
|
One-year: 2.7 inches
| |
|
Two-year: 3.3 inches
| |
|
Five-year: 4.2 inches
| |
|
Ten-year: 5.0 inches
| |
|
Twenty-five-year: 5.8 inches
| |
|
Fifty-year: 6.4 inches
| |
|
One-hundred-year: 7.2 inches
|
[3]
All development shall limit the rate of stormwater
runoff so that no greater rate of runoff is permitted than that of
the site in its natural ground cover condition (meadow conditions)
for the same frequency storm. Where farm fields, disturbed earth or
prior development is the existing condition, meadows shall be used
as the starting base for such calculations regardless of the actual
condition.
[4]
Water quality. Stormwater management facilities
shall be designed so that the one-year, twenty-four-hour postdevelopment
storm will be detained and discharged over a period of at least 24
hours for stormwater quality.
[5]
An overflow system shall be provided to carry
the runoff from the detention basin when the capacity of the existing
storm drain piping system is exceeded. The overflow system shall have
sufficient capacity to carry the runoff that occurs between one-hundred-year-storm
peak flow rate and the capacity of the existing storm drain pipe system.
[6]
Detention basins shall be designed to facilitate
regular maintenance, mowing, periodic desilting and reseeded. Detention
basins shall not be located within floodplains or floodplain soil
or in areas reserved for open space. In subdivisions and residential
developments, shallow, broad basins are preferred to steep sided basins.
The area of the basin that has more than 50% of the perimeter on its
side in slopes greater than 10% or basins that retain stormwater for
more than 24 hours, shall not be included in the open space requirement.
[7]
The maximum side slope of the earth in detention
basin embankment shall be four horizontal to one vertical. The top
or toe of any slope shall be located a minimum of five feet from any
property line. Whenever possible, the side slopes and basins shape
shall conform to the natural topography.
[8]
The minimum top width of the detention basin
shall be 10 feet.
[9]
In order to ensure proper drainage on the basin
bottom, a middle grade of 2% shall be maintained for areas of sheet
flow. For channel flow a minimum grade of 1% shall be maintained.
Additional measures such as soil reinforcement, geotextiles will be
required for grass lined channels within detention basins.
[10]
Emergency spillway for detention
basins shall be constructed on undisturbed ground. All emergency spillways
shall be constructed so that the detention basin is protected against
erosion. The minimum capacity of all emergency spillways shall be
the peak flow rate from the one-hundred-year design storm after development.
The construction material of an emergency spillway shall extend along
the upstream and the downstream berm embankment slopes. The upstream
end of the emergency spillway shall be a minimum three feet below
the spillway crest elevation. The downstream slope of the spillway
shall have as a minimum extend to the toe of the berm embankment.
The emergency spillway shall not discharge over earth fill and/or
easily erodible material.
[11]
The minimum freeboard shall be
one foot. Freeboard is the difference between the design flow elevation
in the emergency spillway and the top of the settled detention basin
embankment.
[12]
Reinforced concrete anti-seep
collars shall be installed around the pipe barrel within the normal
saturation zone of the detention basin berm. The anti-seep collars
and their connections to the pipe barrel shall be watertight. The
anti-seep collar shall extend a minimum two feet beyond the outside
of the principal barrel, maximum spacing between collars shall be
14 times the minimum projection of the collar measured perpendicular
to the pipe. A minimum of two anti-seep collars shall be installed
on each outlet pipe.
[13]
All outlet pipes throughout the
berm shall be reinforced concrete with watertight joints.
[14]
Energy dissipating devices such
as rip-rap, end spills, etc., shall be placed in all basin outlets.
[15]
A perforated riser shall be provided
at each outlet along the detention basins during construction, construction
per sediment control. The risers shall be constructed of metal or
concrete. The risers shall extend to a maximum elevation two feet
above the crest elevation of the emergency spillway. The perforated
risers shall be designed so that the rate of outflow is controlled
by the pipe barrel through the basin berm when the depth of the water
within the basin exceeds the height of the riser. Circular perforations
with a maximum diameter of one inch shall be spaced eight inches vertically
and 12 inches horizontally. Perforations shall be cleanly cut and
suitably coated to prevent corrosion. Trash rack or similar device
shall be provided to prevent debris from entering the riser. All risers
shall have a concrete base attached to the watertight connection.
The base shall be of sufficient weight to prevent flotation of the
riser. An anti-vortex device, consisting of a vertical plate normal
to the basin berm, shall be provided on the top of the riser.
[16]
All drainage channels shall be
designed to prevent erosion of the bed and banks. The maximum permissible
flow velocity shall not exceed those outlined in the Bucks County
Erosion & Sediment Control Handbook. Suitable stabilization shall
be provided where required to prevent erosion of drainage channels.
[17]
Any vegetative drainage channel
requiring mowing of the vegetation shall have a minimum grade of three
horizontal to vertical on those areas to be mowed.
[18]
Because of the critical nature
of vegetative drainage channels, the design of all vegetative channels
shall be the minimum, conformed to the design procedures outlined
in the Bucks County Erosion & Sediment Control Handbook, Part
2 Definitions.
A.
The owner 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. The entire system
shall be designed in accordance with the requirements and standards
of the Upper Southampton Municipal Authority and shall be subject
to their approval.
B.
The system shall also be designed with adequate capacity
and appropriately spaced fire hydrants for fire-fighting purposes.
Review and approval by the Fire Marshal shall be required in order
to ensure that fire protection is provided.
Where no public water is accessible, water shall
be furnished by the owner on an individual lot basis. If wells are
installed on each lot and the lot also contains its own sewage disposal
facilities, the well shall be of the drilled type, cased and grout-sealed
into the bedrock. The well will be required to have a production of
not less than six gallons per minute as established by bailor tests,
and certified by the well driller. Before being placed in consumer
use, it shall be disinfected by the use of sodium hypochlorite or
other acceptable solutions, and a sample collected by a County Health
Department representative for bacteriological examination. A copy
of the result of the above-referred-to bailor test and bacteriologic
examination, and a certificate from the County Health Officer that
the owner has complied with the applicable state and county health
regulations, shall be submitted to the township before the issuance
of building permits in connection with each individual lot in the
subdivision.
A.
The owner shall construct sanitary sewers in such
a manner as to make adequate sanitary sewage service available to
each lot within the subdivision.
B.
The entire system shall be designed in accordance
with the requirements and standards of the Upper Southampton Sewer
Authority and shall be subject to its approval.
[Amended 1-21-1992 by Ord. No. 295]
If the public sewer facilities are not available,
the owner shall provide for sewage disposal on an individual lot basis
according to the rules and regulations adopted by the Bucks County
Board of Health.
If, at the time of final approval, public sanitary
sewer facilities are not available to the subdivision or land development,
but will become available within a period of five years or a period
determined by the Board of Supervisors from the date of recording,
the owner shall be required to install or cause to be installed at
his expense sanitary sewers and sewer laterals to the street line
in accordance with the requirements and standards of the Sewer Authority;
and shall cap all laterals. Review and approval by the Upper Southampton
Sewer Authority shall be required.
A.
The owner shall cause gas, electric power and telephone
facilities to be installed in such a manner as to make adequate service
available to each lot or dwelling unit in the subdivision or land
development.
B.
All public utilities required to service subdivisions
and land developments shall be placed undergound, except for minor
exceptions necessary to permit the overall installation of utilities.
C.
Where practicable, all utilities shall be located
within the street right-of-way, otherwise, easements or rights-of-way
of sufficient width for installation and maintenance shall be provided.
D.
Final plans shall show locations of all utilities
and shall be coordinated with required street tree planting.
[Amended 1-21-1992 by Ord. No. 295]
Grading shall conform in all respects to the
final plan and the requirements and standards of this chapter. Individual
lot grading plans shall be submitted to the township for review by
its Engineer prior to issuance of a building permit.
Additional community facilities may be required
to serve the proposed lots or dwellings in a subdivision or land development.
Where a proposed park, playground or other public facility shown in
the Comprehensive Plan or Community Facilities Plan or parts thereof
is located in whole or in part in a subdivision or land development,
the dedication or reservation of such area may be required by the
Board of Supervisors in those cases in which it deems such requirements
to be reasonable.
