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.
(1) 
The criteria contained in the Appendix, Design Standards, Typical Road Cross Section, and Guard Rail Warrant, shall be observed in the design of streets. [1]
[1]
Editor's Note: These items are included at the end of this chapter.
(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.
[1]
Editor's Note: See Ch. 240, Zoning, of the Code of the Town of Barnstable.
(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.
[1]
Editor's Note: See Ch. 240, Zoning.
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.