A.
Districts. For the purposes of the design standards (Article III), the construction specifications (Article IV), and the typical street cross sections, the Town of Adams is hereby divided into two districts designated “mountain” and “plain.” Land having average slope of greater than 10% shall be considered mountain and of 10% or less plain.
B.
Design guides. The subdivision shall conform, insofar as practical, to any elements in a Town development policy which the Planning Board may adopt, provided that such elements are given public hearing in the same manner as prescribed for amendments to subdivision regulations and made available along with copies of the subdivision regulations. The subdivision shall be designed and improvements made by the developer consistent with the requirements of Articles III and IV. Design and construction shall:
(1)
Reduce, to the extent reasonably possible, the following:
C.
Cross section. Grading, location of pavements, utilities,
and other improvements shall be designed and located as indicated
on the typical street cross sections (see Appendix for sample).
D.
Flood hazard avoidance. Any subdivision located in any part within any flood hazard district established under Chapter 125, Zoning, of the Town Code shall comply with the following:
(1)
Subdivision design shall be consistent with the need
to minimize flood damage within the flood-prone area, through use
of clustering, open space reservation, street profile design, and
drainage design.
(2)
All public utilities and facilities, such as sewer,
gas, electrical, and water systems, shall be located and constructed
to minimize or eliminate flood damage.
(3)
Drainage systems shall be designed in consideration
of possible flooding to the base flood elevation.
(4)
Each lot shall have a means of vehicular egress over
surfaces no lower than the base flood elevation.
A.
Location and alignment.
(1)
All streets and paths in the subdivision shall be
designed so that, in the opinion of the Board, they will provide safe
pedestrian and vehicular travel.
(2)
Provision satisfactory to the Board shall be made
for the proper projection of streets and paths or for access to adjoining
property which is not yet subdivided.
(3)
Reserve strips prohibiting access to streets or adjoining
property shall not be permitted except where, in the opinion of the
Board, such strips are in the public interest.
(4)
Street jogs with center-line offsets of less than
150 feet should be avoided.
(5)
Street configuration shall be designed, together with
reserved open space, to minimize the number of lots having frontage
exclusively on collector streets.
(6)
The minimum center-line radii of curved streets shall
be not less than the following:
|
Mountain
|
Plain
| ||
|---|---|---|---|
|
Lane
|
50 feet
|
75 feet
| |
|
Minor Street
|
100 feet
|
150 feet
| |
|
Collector Street
|
250 feet
|
350 feet
|
(7)
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 60°.
(8)
Any group of 20 or more lots shall provide for two
means of egress.
(9)
Property lines at street intersections shall be rounded
or cut back to provide for a radius at the edge of the traveled way
of not less than 30 feet at intersections with a collector street
and 20 feet for intersections involving only minor streets or lanes.
(10)
Street intersections on arterial streets (major
inter-town streets) shall be spaced not less than 400 feet apart.
(11)
Pathways or sidewalks connecting existing trails,
paths, or sidewalks should be preserved or created wherever reasonable,
not necessarily following the streets, and should be developed in
other locations where indicated by traffic, access to public or recreational
facilities, or other reasons. When located within the street right-of-way,
sidewalks shall be located at or near the outside of the layout but
varied in horizontal location so as to minimize disturbance of natural
features of the land and vegetation.
B.
Width.
(1)
The minimum width of street rights-of-way shall equal
40 feet for lanes and 50 feet for minor and collector streets, except
that the width of minor streets may be reduced to not less than the
width of the traveled way plus 18 feet in cases where extension of
the minor street is precluded.
(2)
The minimum width of rights-of-way for off-street
paths, where proposed, shall be eight feet.
C.
Grade.
(1)
Grades of streets shall be not less than 0.5%. Except
for short intervals, grades shall be not more than the following:
|
Mountain
|
Plain
| ||
|---|---|---|---|
|
Lane
|
14%
|
12%
| |
|
Minor Street
|
12%
|
10%
| |
|
Collector Street
|
8%
|
6%
|
(2)
On any street where the grade exceeds 6% on the approach
to an intersection, a leveling area with a slope of not more than
4% shall be provided for a distance of not less than 50 feet measured
from the nearest exterior line of the intersecting street.
(3)
Vertical curves are required whenever the algebraic
difference in grade between center-line tangents is 2.0% or more.
(4)
Street center-line profile shall at no point be less
than three feet above the grade of adjacent wetlands or marsh.
D.
Sight distances. Forward stopping sight distances
shall not be less than the following:
|
Mountain
|
Plain
| ||
|---|---|---|---|
|
Lane
|
100 feet
|
125 feet
| |
|
Minor Street
|
150 feet
|
225 feet
| |
|
Collector Street
|
300 feet
|
400 feet
|
E.
Dead-end streets.
(1)
Dead-end streets shall not be allowed except for lanes
unless, in the opinion of the Board, they are necessitated by topography
or other site conditions.
(2)
Dead-end streets shall be provided at the closed end
with either a turnaround having an outside roadway diameter or at
least 100 feet and a property line diameter of at least 115 feet or
an alternative configuration accommodating the turning of a vehicle
with thirty-foot wheelbase.
F.
Superelevation. On collector streets where appropriate,
curves may be superelevated at a maximum rate of 0.06 foot per foot
for a design speed of 30 miles per hour.
A.
Easements for utilities across lots or centered on
rear or side lot lines shall be provided where necessary and shall
normally be 20 feet wide.
B.
Where a subdivision is traversed by a watercourse,
drainageway, channel or stream, the Board may require that there be
provided a stormwater or drainage easement of a minimum width of 20
feet to conform substantially to the lines of such watercourse, drainageway,
channel or stream and to provide for construction or other necessary
purposes.
C.
Drainage easements outside of the area of the subdivision,
but occasioned by it, may be required of the subdivider.
D.
Slope easements shall be provided where cut or fill
slopes cannot be contained within the street right-of-way.
A.
Storm drainage, culverts, and related facilities shall
be designed to permit the unimpeded flow of all natural watercourses,
to ensure adequate drainage of all low points along streets, to control
erosion, and to intercept stormwater runoff along streets at intervals
reasonably related to the extent and grade of the area drained. To
the maximum extent feasible, stormwater shall be recharged rather
than piped to surface water. Peak stream flows at the boundaries of
the development shall be not more than 10% higher following development
than prior to development.
B.
Storm sewers, retention basins, and leaching basins
shall be based on a twenty-year frequency storm, and culverts shall
be based on a fifty-year frequency storm. Design shall employ backflow
valves or other devices as necessary to avoid damage from reverse
circulation of floodwaters.
C.
Design shall be based upon either the Rational Method or Manning Formula. Water velocities shall be between two and 10 feet per second. The coefficient of runoff used shall be not less than 0.45 for subdivided areas. All developable land tributary to facilities being designed shall be assumed to be subdivided, except within the mountain district of this chapter and the floodplain district of Chapter 125, Zoning, of the Town Code. Leaching basins or a catch basin to manhole system of drainage is required, with no storm sewers of less than twelve-inch inside diameter and with catch basins at all low points and sags, near the corners of the roadway at intersecting streets, and at intervals of not more than 350 feet on continuous grades. The Board may require test borings at leaching basin locations where percolation is in doubt.
A.
Provisions shall be made for water supply to each
lot and for fire protection. When available, the water supply shall
be from the Adams Fire District system, in which event system design
shall be as specified by the District, evidenced by certification
from the District that it approves the design and will permit connection.
B.
Where connection to the public system is not feasible,
a subdivision plan shall be approved only upon presentation of evidence
satisfactory to the Board, upon advice of the Board of Health, that
adequate and suitable groundwater is available and upon evidence satisfactory
to the Board, upon advice of the Fire Chief, that adequate provisions
for fire fighting have been made.
A.
When the subdivision abuts the existing sewerage system
of the Town, connection shall be made. When the subdivision abuts
a proposed sewer extension for which an appropriation has been authorized
by Town Meeting action, the subdivision shall be sewered so that connection
can be made as such extension progresses. Where gravity connection
is not feasible, a lift station shall be located and installed in
accordance with the requirements of the Sewer Commission.
B.
Individual or private sewerage systems will be permitted
only under conditions other than the above.
A.
Open spaces. Before approval of a plan, the Board
may require that an appropriate area be reserved for a possible park
or parks and by appropriate endorsement on the plan require that no
building be erected upon such reserved area for a period of three
years without the Board's approval. Such reservation shall be made
where particular natural features, abutting public land, or the potential
neighborhood need for recreation space make later public acquisition
appear desirable, but in no event shall required reserved areas exceed
5% of the total area of the subdivision, unless so required by zoning
or other regulations.
B.
Protection of natural features. Due regard shall be
shown in the design and during construction to retain in a natural
state all natural features and similar community assets which will
add attractiveness and value to the subdivision. Such features may
include trees of four-inch caliper, wetlands (as defined in MGL c.
131, § 40), watercourses, land within 200 feet of a river,
pond, or stream, slopes greater than 15%, points having the highest
ground elevation within 500 feet, other scenic points, and locations
with historic associations.
C.
Undergound wiring. All wiring, cables, and other appurtenances
of electrical power, telephone, and fire alarm systems shall be placed
underground within the limits of the street right-of-way, except where
such underground installation would, in the judgment of the Planning
Board, cause undue hardship by reason of topography, subsoil conditions,
or other site peculiarities or by reason of the existing development
pattern.
