Existing contours shall be preserved insofar as it is practical. In
any event no change shall be made in existing contours that adversely affects
land abutting the proposed subdivision. Due consideration shall be given to
the attractiveness of the layout and the preservation of natural features.
Roads shall be located so as to minimize the amount of grading required. All
work on the ground hereinafter specified shall be performed by the applicant
in accordance with these rules and regulations, in conformity with approved
definitive plans and specifications and other construction requirements of
the Town agencies concerned, and the satisfaction of such agencies.
A.
Location of streets.
(1)
The streets shall be designed and located so as, in the
opinion of the Board, to be continuous and in alignment with existing streets;
to provide adequate access to all lots in the subdivision; by streets that
are safe and convenient for travel; to lessen congestion in such streets and
adjacent public streets; to reduce danger from the operation of motor vehicles;
to secure safety in case of fire, flood, panic and other emergency; to insure
compliance with applicable Zoning Ordinance; to secure adequate provision
for proper drainage and water, sewers and other utilities; and to coordinate
the streets in the subdivision with each other and with the existing street
system of the Town, and the streets in neighboring subdivisions.
(2)
The proposed streets shall be designed and located so
as to conform to the Master Plan, if any, as adopted in whole or in part by
the Board.
(3)
Provision satisfactory to the Board shall be made for
the proper projection of streets, or for access to adjoining property that
is not yet subdivided.
(4)
Due consideration will be given by the Board to the attractiveness
of the layout and to the conformance of the ways to the topography. Streets
shall be laid out with curvilinear lines wherever possible.
(5)
Reserve strips prohibiting access to streets or adjoining
property shall not be permitted, except where, in the opinion of the Board,
such strips shall be in the public interest.
(6)
Where ways are extended to the property line forming
stub streets for future tie, that way shall be paved to the property line.
(7)
Subdivisions shall be designed so as to minimize the
length of roads.
(8)
Road layouts shall be located and designed so as to create
easily accessed lots at or near grade level.
(9)
Subdivisions shall be designed so as to avoid creating
lots with double frontage, except when one frontage is on a major street.
(10)
Where a subdivision borders on a major street, access
to lots shall be provided from a parallel local street and access to the major
road shall be minimized.
(11)
No road, with or without fill, shall be located within
a velocity zone or within the one-hundred-year floodplain, as shown on the
special Flood Insurance Rate Maps, and as further defined by the topographic
information shown on the plan.
(12)
Where access to a subdivision crosses land in another
municipality, the Board may require certification, from appropriate authorities,
that such access is in accordance with the Master Plan and subdivision requirements
of such municipality and that a legally adequate performance bond has been
duly posted or that such access is adequately improved to handle prospective
traffic.
B.
Width, alignment and grades of streets.
(2)
Streets shall intersect with minimum center-line offsets
of 150 feet unless otherwise specified by the Board.
(3)
Streets shall be laid out so as to intersect as nearly
as possible at right angles. No street shall intersect any other street at
less than 75°.
(4)
Where the angle of intersection between two streets varies
more than 10° from a right angle, the radius of the curve at the curbline
at the obtuse angle shall be less and at the acute angle shall be correspondingly
greater than the radius specified in the Appendix to the extent approved or
required by the Board.
(5)
All changes in grade exceeding 2% shall be connected
by vertical curves of the length indicated in the design standards table in
these regulations.
(6)
No center-line gradient is to exceed 6% on any curve
except when the curve is superelevated and the design is acceptable to the
Board's engineer. All curves on a major road shall be superelevated in
conformance with AASHTO Guidelines unless otherwise approved by the Planning
Board's engineer. Superelevations shall not exceed E = 0.06.
(7)
No center-line gradient is to exceed 6% within 500 feet
of a dead-end.
(8)
No street shall intersect another street at a gradient
in excess of 2% for a distance of at least 40 feet from the intersection as
measured from the edge of the right-of-way.
(9)
Way lines shall be parallel unless otherwise specified
by the Planning Board.
(10)
Streets shall be designed in accordance with AASHTO Standards
unless otherwise specified.
C.
Dead-end streets.
(1)
Dead-end streets shall be not less than 100 feet long
nor more than 750 feet. The length of the dead-end street shall be measured
from the intersection with a street providing alternative access, to the beginning
of the cul-de-sac or turnaround T. The Board may grant a waiver from the maximum
length of the dead-end street if the Board determines that there is a reasonable
expectation that the street will become an additional means of access or egress
to a future street connection on adjacent, undeveloped land. No extension
of a cul-de-sac or turnaround T to adjacent land shall be permitted where
such extension will lengthen a dead-end street beyond the seven-hundred-fifty-foot
maximum length.
(2)
Minor and secondary dead-end residential streets shall
be provided at the closed end with a turnaround having an outside paved roadway
diameter of 90 feet and a right-of-way diameter of 105 feet.
(3)
No major dead-end street and secondary nonresidential
dead-end street shall be permitted, unless the Fire Department, DPW, and/or
Police Department provide the Board with written determination that there
will be no compromise to public safety of both pedestrian and vehicular traffic.
Where the Board grants a waiver to allow a dead-end street, the street shall
be provided at the closed end with a turnaround having an outside paved roadway
diameter of not less than 94 feet, 30 feet of the pavement width on the cul-de-sac
and with a right-of-way diameter of at least 110 feet. culs-de-sac shall be
shaped in accordance with ASHTO standards for circular and circular offset
culs-de-sac for single-unit trucks.
(4)
Dead-end streets shall be constructed all the way to
the property line and shall be designed and located so as to allow them to
continue to abutting property.
(5)
A minor road serving less than 10 lots may be constructed
with a turnaround T or Y in lieu of a cul-de-sac at the discretion of the
Planning Board. The turnaround T shall be designed according to the drawings
in the appendix entitled "Paved Turnaround T" or shall be an alternative design
approved by the Planning Board.
(6)
Natural vegetation shall be retained in the center of
the turnaround. Damaged areas shall be replanted with a combination of ground
cover, shrubs and/or trees common to the Cape such as: bearberry, bayberry,
inkberry, American holly, beach grape; Rugosa rose, beach gum, red cedar,
juniper, red oak, thornless honey locust, American red maple, checkerberry,
Shore juniper or sargent juniper, unless otherwise approved by the Planning
Board.
(7)
Upon construction of an extension of a dead-end street,
the easement for the existing turnaround shall terminate in accordance with
the provisions of Chapter 41 of the General Laws. The paved surface of the
turnaround shall be removed so as to create a roadway of a uniform width.
Drainage, road surface and road shoulders shall be repaired and/or reconstructed
and revegetated in accordance with all the requirements of the Subdivision
Rules and Regulations.
D.
Clearance above roads. Overhanging vegetation shall be
cleared to a height of 15 feet above roads, to provide clearance for trucks
including Fire Department ladder trucks.
A.
General provisions.
(1)
The subdivision shall be designed so that all drainage
shall be contained and disposed of within the subdivision; no drainage shall
be discharged on to adjoining property or on to the public right-of-way at
a rate greater than existed prior to the construction of the subdivision.
The applicant shall submit information as to pre- and post-development runoff
volumes and peak flows during the ten-year and one-hundred-year storm. No
drainage shall be discharged directly into any wetland or surface water body,
or into any drain, ditch, culvert or retention pond that leads into wetlands
or surface water bodies.
(2)
All drainage systems within the subdivision shall be
designed in accordance with the soil conservation service method or an alternative
system acceptable to the Board's engineer. Calculations shall be made
from the source of drainage runoff using topographic maps for the entire drainage
area, including those areas outside the subdivision. Copies of all drainage
calculations shall be submitted with the definitive plan. Percolation tests
may be required at the discretion of the Board.
(3)
Drainage systems shall be designed and installed so as
to prevent stormwater runoff from becoming a hazard or a nuisance to the subdivision
residents or the public at large. The applicant is ultimately responsible
for the adequacy of the drainage system in reaching this end. Should the system
not adequately achieve the goal, the applicant shall make whatever modifications
are needed to ensure that the drainage system performs adequately in the opinion
of the Planning Board. All modifications shall be acceptable to the Board's
engineer.
B.
Subsurface drains or subdrains.
(1)
In areas where the finished grade of the roadway is less
than four feet above the water table or in areas where less than four feet
of fill is placed above water in swampy places or any standing water, or in
other areas, where in the opinion of the Board the subgrade must be drained,
a system of subdrains shall be designed for such areas. The subdrain shall
consist of a minimum of one longitudinal drain for each forty-foot width of
roadway or fraction thereof.
(2)
In addition, laterals shall be required as directed by
the Board in areas in which an undue amount of water could accumulate in the
subgrade. The system of subdrains shall be discharged into the storm drainage
system or otherwise disposed of in a manner satisfactory to the Board.
(3)
Subdrains shall also be required where test borings show
an impervious layer of soil above a permeable layer of soil which is located
at or above one foot below the proposed basement floor elevation.
C.
Storm drains.
(1)
A complete storm drain system shall be designed for each
street of the subdivision and, to the satisfaction of the Board, shall be
so laid out to provide adequate drainage of all portions of the street system
so that water does not accumulate thereon, to intercept stormwater runoff
from the adjacent lots of the subdivision, and to eliminate undesirable or
unnatural accumulation of water on any portion of the subdivision or surrounding
property. Those conditions which result from a ten-, twenty-five- or fifty-year
storm as required shall be assumed as a basis for design of the street drains.
The storm drain system shall include gutters, catch basins, manholes, culverts,
drain lines, headwalls, vegetated swales, detention ponds and such other items
as may be required to complete the system to the satisfaction of the Board.
Information regarding a procedure which may be utilized in drainage designs
is available from the Town Engineering office.
(2)
The Soil Conservation Service drainage calculation methodology
or an alternative systematic method acceptable to the Board's engineer
shall be used in the design of the drainage systems.
(3)
Best management practices (BMPs) shall be utilized to
treat the first one inch of rainfall, or 1/2 inch of runoff, whichever is
greater. BMPs shall consist of grass-lined swales, grass-lined retention basins,
or other treatment facilities acceptable to the Board's engineer.
(4)
Side slopes on BMPs shall not be steeper than four to
one and generally should be much flatter. BMPs shall be distributed throughout
a subdivision and not concentrated in any one location to better dilute the
effects of any pollutants left untreated. For this reason, the use of swales
in areas with relatively level terrain is desirable. The bottom of the BMPs
should be four feet above the probable high groundwater. All BMPs shall be
located within drainage easements or the road right-of-way.
(5)
Catch basins shall be located in pairs, one on each side
of the roadway, at all low points or sag curves in the roadway, at intervals
of not more than 300 feet on continuous grades of the roadway, and at or near
the corners of the roadway at intersecting streets.
(6)
Manholes shall be located at all changes in direction,
either horizontally or vertically, of a drain line or at the intersection
of two or more drain lines, or so located that no drain line greater than
300 feet in length would exist without either a catch basin or manhole.
(7)
Culverts shall be designed on the assumption that the
entire drainage area is built up to that density and in the manner which the
applicable section of the Zoning Ordinance[1] allows. The calculations (or a copy thereof) necessary to determine
the size of any culvert which carries a brook, stream, river or other natural
waterway shall be submitted to the Board for review. All culverts shall have
a headwall at each end, and any culvert over 36 inches in diameter shall include
at the upstream end additional protection, as approved by the Board, for the
roadway side slopes.
(8)
All drains shall be a minimum of 12 inches in diameter
and shall be laid on a slope of not less than 1/2 of 1%. The minimum design
velocity shall be three feet per second and maximum design velocity shall
be 10 feet per second. If the system is designed as a self-cleaning system,
the Board may accept a lesser minimum slope for the drain lines. Pipe shall
have a capacity 25% greater than required by the calculations. In such cases
as it is deemed necessary and acceptable by the Board and its engineer, surface
water may be disposed of by a leaching system of the proper size and design.
Calculations for the design of such system shall be submitted with other drainage
calculations for the subdivision and under the same provisions. Provision
shall be made for the disposal of surface water intercepted or collected by
the system in such a manner that no flow is conducted over Town ways, or over
the land of others unless a drainage easement is obtained or unless such flow,
in essentially the same quantity, previously existed in the same location.
Where adjacent property is not subdivided, provision shall be made for extensions
of the system by continuing appropriate drains to the boundary of the subdivision
at such size and grade as will allow their proper projection.
(9)
All recharge systems shall be designed with a fail-safe
feature which will provide a safe, legal off-the-road overflow area for the
runoff in the event that the catch basins overflow. The overflow areas shall
be sized to accommodate a one-hundred-year storm. The overflow areas shall
preferably be located in naturally vegetated shallow kettle holes or other
depressions; however, if there are not any naturally occurring areas, then
the shallow areas with gently sloping sides shall be excavated for stormwater
storage. Overflow areas shall be located within drainage easements. Separate
drainage lots are discouraged and will not be permitted without the permission
of the Planning Board.
(10)
A headwall shall be provided at the outfall end of all
drains where required.
(11)
All recharge infiltration type drainage systems shall
be designed by the applicant's engineer to prevent stormwater from breaking
out of any slopes. Breakout calculations shall be provided by the applicant's
engineer.
A.
Easements for utilities. Easements for utilities shall
be provided and recorded as required and centered on lot lines where practical.
B.
Stormwater and drainage easements. Where a subdivision
is traversed by a watercourse, drainageway, channel or stream, the Board may
require that there be provided a stormwater easement or drainage right-of-way
of adequate width to conform substantially to the lines of such watercourses,
drainageway, channel or stream, and to provide for construction, maintenance,
or other necessary purposes.
C.
Access easements. Access easements may be required where
deemed necessary.
D.
Slope easements. Slope easements may be required where
deemed necessary.
E.
Sight and scenic easements. Sight and/or scenic easements
may be required where deemed necessary.
A.
Where required. Sidewalks shall be installed on both
sides of Major Streets.
B.
Sidewalks conditionally required. Sidewalks shall be
installed on one or both sides of a secondary street and a minor A street,
unless in the opinion of the Planning Board, pedestrian safety would not be
substantially served by their construction. Where sidewalks are not required,
the Board may require that the grading of the right-of-way be so executed
as to make possible later additions of sidewalks without major regrading.
C.
Location of paved road surface. In order to accommodate
a sidewalk and/or bicycle path, the Planning Board may require that the paved
surface of the roadway be offset to one side of the right-of-way.
D.
Green strips. Sidewalks and/or bicycle paths shall be
separated from the roadway by a strip of land loamed and seeded to the specifications
of § 810-48, Grass plots. Sidewalks and/or bicycle paths shall be
located as close as possible to the outside line of the right-of-way. Street
trees shall be planted in the green strip.
E.
Sidewalk length. Sidewalks shall extend the full length
of each side of the street.
F.
Sidewalk width. Sidewalks shall have a minimum width
of five feet along major and secondary roads. All sidewalks shall conform
to American Disabilities Act requirements and Massachusetts Architectural
Access Board standards, 521 CMR, and as may be amended.
A.
All streets shall have bituminous concrete "Cape Cod
berms," vertical granite or sloped granite curbing at the discretion of the
Board. In the case where granite is used, the curbing shall extend along the
entire circumference of curves plus six feet at all intersections. Vertical
inlet curbing shall be used for all catch basins when vertical granite curbing
is used.
B.
As a general guide bituminous concrete Cape-Cod-type
berms placed at the time of paving are required on all roads regardless of
slope. Roads located in or near urbanized village centers, commercial areas,
industrial areas and other areas designated by the Planning Board will require
the installation of granite curbing at the discretion of the Planning Board.
A.
All lots within the subdivision shall comply with the
Zoning Ordinance of the Town,[1] or with terms of any variance from such requirements which may
have been specifically granted by the Board of Appeals. Percolation tests
may be required on each lot at the discretion of the Board. Lot numbers as
shown on the approved plan shall be conspicuously displayed with a suitable
marker which shall be visible from the road layout.
B.
Lots shall be located and designed so as to provide building
sites with positive drainage away from buildings.
Before approval of a plan, the Board may also, in proper cases, require
the plan to show a park or parks suitably located for playground or recreation
purposes or for providing light and air. The Board may, by appropriate endorsement
of the plan, require that no building be erected upon such park or parks for
a period of not more than three years without its approval. These parks shall
be offered for just compensation to the Town in the form of a deed, with the
Town having the option of accepting or releasing these areas within the three-year
period.
Regard shall be shown for all natural features, such as large trees,
watercourses, scenic points, historic spots, and similar community assets,
which, if preserved, will add attractiveness and value to the subdivision.
Wherever retaining walls may be required, design and type of wall construction
shall be submitted to the Board for approval prior to installation.
A.
General requirements. The Board may require that the
plan show utilities of the kinds existing in the public ways nearest to the
subdivision, or which in the opinion of the Board are likely to be laid in
such public ways within the reasonably near future and which will be necessary
for the health, safety, or convenience of the prospective occupants of the
subdivision.
B.
Location. The utilities and sleeves for house connections
shall be located as shown on the typical road cross sections. [1] The number and type of sleeves for house connections will be directed
by the Board.
[1]
Editor's Note: The typical road cross section diagrams are included
at the end of this chapter.
C.
Sewer system design. The design of the sewer system,
if required, shall be as directed and approved by the Department of Public
Works. A functional sewer collection system complete with service connection
to the property line shall be required in areas that now have service or are
scheduled for such service within three years.
D.
Public supply standards. The applicant shall work with
the Fire District or water company and provide the Board with documentation
of compliance with their water supply standards. Wherever feasible, water
supply shall be provided from a public water supply system. Where any part
of any lot is at elevation 100 feet (msl) or higher, the applicant shall submit
calculations documenting supply adequacy.
E.
Private supply standards. Where connection to an adequate
public water supply is infeasible, the Planning Board shall approve a subdivision
only upon its determination, following consultation with the Fire Department,
that reserved access to a fire pond or other provisions for water supply will
adequately provide for fire safety.
F.
Design of water system. The design of the water system
and provision for hydrant service shall be as directed or approved by the
Fire District or water company in accordance with the typical road cross sections.
In the case where sidewalks are to be constructed on one side of the roadway,
the water and hydrants shall be on the opposite side of the roadway.
G.
Location of hydrants. The location and type of hydrants
and size of pipe serving the hydrants shall be as directed or approved by
the Fire District or water company, if required.
H.
Fire alarm boxes. The location and type of the fire alarm
boxes and point of entry into the subdivision of the connecting fire alarm
cable shall be as directed by the Fire Chief. The applicant shall furnish
and install the necessary ducts, fire alarm boxes, and electric cable.
I.
Electric power system. The design and location of the
electric power system shall be as directed by the electric company. The system
shall be constructed to a standard which will enable the electric company
to accept it as part of their system upon completion.
J.
Gas service. The applicant shall consult the gas company
relative to coordination of the installation of gas pipes, if gas service
is to be installed.
K.
Telephone service. The applicant shall consult with the
telephone company relative to the installation of telephone service.
L.
Location of wires. All electrical, telephone, and other
utility wires shall be placed below ground in every subdivision, unless the
Board determines that such placement is not feasible or is not in the best
interest of the Town.
M.
Utility service connections. All service connections
for utilities shall be clearly marked at the lot line and shall be installed
so that electric, telephone, sewer, and water services are located on the
lot line perpendicular to the street, and the gas service is located on the
alternate lot line, and said service connection shall be installed prior to
the completion of the fill.
