A. 
Basic requirement. All subdivisions shall be designed and improvements made by the developer consistent with the requirements of Article IV. Subdivisions shall be designed to be consistent with one of the following subdivision types, as described further in Appendix A, or shall be divided into subareas, each of which is designed to be consistent with one of these types:
(1) 
Village. Village subdivisions are appropriate within or adjacent to densely developed areas, or where a future village center is proposed. They are intended to continue the pattern of traditional development. In light of relatively small lots and short frontages, drainage systems will be closed, and sidewalks and granite curbs will be installed.
(2) 
Gathering. Gathering subdivisions are intermediate between village and dispersed, such as in the developed portion of a subdivision having low overall density but clustered lots. Drainage will usually be closed, but sidewalks will be required only in certain cases. Curbing, if provided, need not be vertical granite. The road edge may sometimes be a grass berm.
(3) 
Dispersed. Dispersed subdivisions involve large lots and long frontages, so drainage may normally be open, streets may be without curbs or berms, and sidewalks are required only in special circumstances.
B. 
General design guidelines. The subdivision plan should reflect the suggestions of Appendix B,[1] which contains general design guidelines.
[1]
Editor's Note: Appendix B is included at the end of this chapter.
C. 
Conformance with Master Plan. The subdivision plan shall conform insofar as practical to any elements of the Williamstown Master Plan which have been adopted by the Planning Board in the same manner as prescribed for amendments to this chapter and which are made available along with copies of this chapter.
D. 
Standards of construction. Standards of construction not otherwise specified hereunder shall be those of the Williamstown Department of Public Works Construction Standards or, where that agency has no standard, the Standard Specifications for Highways and Bridges of the Massachusetts Department of Public Works (latest edition with amendments in effect at that time).
E. 
Typical cross sections. Design and construction shall conform to the general configuration shown in the typical cross sections of Appendix A[2] and to the detailed requirements shown on the Street Cross Sections incorporated into Chapter 113, Road Construction Standards.
[2]
Editor's Note: Appendix A is included at the end of this chapter.
A. 
Location.
(1) 
All streets in the subdivision shall be located so that they will provide safe vehicular travel.
(2) 
Streets shall be continuous and in alignment with existing streets as far as is practicable.
(3) 
If adjoining property is not subdivided, proper provision for extending streets shall be made, except in the case of developments under minor lane residential development of § 170-3.4.
(4) 
Reserved strips of property prohibiting access to streets or adjoining property will not be permitted.
(5) 
Center-line offsets for intersecting streets shall either be zero or be more than 150 feet.
(6) 
Streets shall intersect with tangent sections of at least 40 feet length on each street meeting at not less than 60° (ideally at 90°).
(7) 
Intersections shall provide for block lengths of between 600 and 1,000 feet, and on collector streets shall be spaced not less than 600 feet apart.
(8) 
The center line of the paved surface shall coincide as closely as possible with the right-of-way center line. In no case shall either edge of the paved surface be closer than 10 feet to the edge of the right-of-way.
(9) 
Street location creating lots with frontage on two streets may be required by the Planning Board in order to avoid driveways opening onto collectors.
B. 
Geometric standards. Streets shall be designed to meet the geometric standards of the following table, except where departure is authorized or required for minor lanes under §§ 170-3.4 and 170-4.2H. The Planning Board may impose more demanding requirements, but only where exceptional conditions make that necessary for public safety. "Hillside" applies to streets or street segments where average slopes exceed 15% across the street center line.
Geometric Requirements
Street Type
Requirements
Lane/ Minor Lane
Minor Street
Collector Street
Non- residential
Minimum center- line radius (feet)
Basic
125
150
250
250
Hillside
75
100
150
N/A
Minimum design speed for sight distance (mph)*
All classes
20
20
30
30
Pavement edge radius at corner (feet)
Village type
10
10
20
N/A
Others
25
25
30
30
Minimum right-of- way (feet)
Basic
45
50
60
50
Hillside
40
45
45
N/A
Minimum pavement width (feet)
Basic
20
24
30
26
Hillside
18
20
22
N/A
Maximum center- line grade (%)
Basic
12%
10%
8%
10%
Hillside
12%
12%
10%
N/A
Minimum leveling area length (feet)
[See § 170-4.2D(2).]
Basic
40
40
40
50
Hillside
20
20
20
N/A
NOTES:
"N/A" indicates a category which is not allowed.
* Design to based on AASHTO standards and, for intersections, the highest street category involved.
C. 
Dead-end streets.
(1) 
Permissibility. Dead-end streets shall not be allowed in village subdivisions unless there is no feasible alternative. Where they are employed, there or elsewhere, dead-end streets shall provide access to no more than 12 dwelling units potentially allowable under current zoning and any restrictions proposed, unless, in the opinion of the Board, serving a greater number is necessitated by topography or other local conditions, and any concerns over emergency access in contingencies have been resolved.
(2) 
Minimum length. Dead-end streets shall be no shorter than 100 feet measured from the center of the turnaround to the intersecting street sideline.
(3) 
Turnaround.
(a) 
Dead-end streets shall be provided at the closed end with a fourteen-foot wide turning lane providing an outside turning radius of 40 feet, and a property line diameter of 105 feet, or an alternative turnaround designed for a vehicle of thirty-foot length, eight-foot width, and having an outside turning radius of 57 feet. Standard or teardrop turnarounds shall have vegetated islands, with plantings selected and placed to preserve safe sight distances.
(b) 
Except that for minor lanes, right-of-way property line diameter may be reduced to 80 feet, outside turning radius to 30 feet, and vegetated islands may be omitted.
D. 
Grades.
(1) 
Maximum and minimum. Center-line grades of all streets shall be not greater than indicated in the Geometric Standards Table, except where, because of unusual conditions, an increase of not more than 1.0% for distances of not more than 300 feet improves the degree to which the design guidelines of § 170-4.1B are met. Center-line grade shall be not less than 1.0%.
(2) 
Intersection leveling areas. Center-line grades shall not exceed 4% within leveling areas as specified in the Geometric Standards Table, with distances measured outwards from the pavement edge of an intersecting street.
(3) 
Vertical curves. Changes in grade exceeding 1% shall be connected by vertical curves of sufficient length to afford a passing sight distance as specified in the Geometric Standards Table, unless drainage considerations dictate otherwise for sag vertical curves.
(4) 
Cross-slope. The street surface shall have a cross slope of 3/8 inch per foot on each side of the center line.
(5) 
Wetland relationship. Center-line profiles shall be at least three feet above the grade of adjacent wetlands.
(6) 
Volume balance. Street grades shall be so designed that the volume of cuts and fills made within the subdivision's rights-of-way approximately balance, except to offset peat, boulders or other unusable materials to be removed.
(7) 
Grade change limitation. Proposed center-line grade shall not be more than seven feet above or below the existing center-line grade.
E. 
Street construction. Materials and construction for streets shall comply with Chapter 113, Road Construction Standards, as most recently revised.
F. 
Curbs and berms.
(1) 
Requirement. Curbs shall be provided on both sides of all streets in village subdivisions, and curbs or bituminous berms shall be provided in other subdivisions as follows:
(a) 
Where curb grade exceeds 8%.
(b) 
Where street pavement edge radius is less than 75 feet.
(c) 
Where street center-line averages less than 50 feet per dwelling unit.
(d) 
Where necessitated by unusual needs for stormwater control.
(2) 
Materials. Where curb or berm is required, materials shall be as follows, in each case complying with Chapter 113, Road Construction Standards:
(a) 
Granite curbing type VA 4: frontage average under 50 feet per housing unit, or village subdivision.
(b) 
Grass berm: Frontage average over 100 feet per housing unit; curb grade does not exceed 8%; street edge radius is at least 75 feet; and area drainage characteristics are demonstrated to the satisfaction of the Planning Board to be suitable for such berms.
(c) 
Six-inch bituminous concrete berm: all other cases requiring curb or berm.
(3) 
Handicapped access. Where sidewalks are constructed, sidewalk ramps shall be provided at each intersection, designed and constructed in compliance with Chapter 113, Road Construction Standards, and the Rules and Regulations of the Architectural Access Board, 521 CMR, whichever is more stringent.
G. 
Driveways. All driveways must be paved from the completed road surface to the lot line with at least three inches of bituminous concrete unless roads are to be gravel. All driveway slopes must end at the street right-of-way, then continue forward to the completed road surface in the same grade as the sidewalk strip and/or shoulder in order to allow proper drainage of surface water.
H. 
Minor lanes. The following shall apply to minor lane residential developments approved under § 170-3.4:
(1) 
General. Minor lanes shall be designed with consideration for the natural contours of the landscape, and shall provide adequate drainage at all points, while minimizing erosion both on and beside the road. Depressions shall be filled to a grade above that of the adjacent roadside and, where possible, natural drainage measures (i.e., swales and retention ponds) shall be employed rather than storm sewers and catch basins. Where natural drainage is used, drainage easements shall be provided to permit maintenance and to provide for possible water accumulation. Appropriate measures shall be taken to reduce siltation and to preserve and restore roadside vegetation.
(2) 
Design.
(a) 
Reductions from the width of the traveled way required for a lane under § 170-4.2C may be permitted, but in no case shall the width of the traveled way of a minor lane be less than 12 feet, with an additional two feet in width cleared of branches and obstructions. The right-of-way width shall be not less than 33 feet.
(b) 
Grades shall not exceed 12%, and center-line radius shall be not less than 75 feet. Where the traveled way is permitted to be narrower than required at § 170-4.2C for a lane and more than 300 feet long, there shall be turnouts allowing vehicles to pass.
(c) 
At intersections with paved roads, there shall be a leveling area as provided by § 170-4.2D(2) unless the Planning Board authorizes substitution of a paved apron, subject to DPW approval on a case-by-case basis.
(3) 
Construction. Construction of minor lanes shall conform, at a minimum, to the requirements of Section II.A.1 of the Williamstown Department of Public Works Construction Standards for gravel roads which fall under minor lane status.
(4) 
Maintenance. Minor lanes are not intended to be accepted as public ways or to be otherwise maintained by the Town of Williamstown. Prior to the endorsement of approval on a minor lane definitive plan, the applicant shall be required to provide assurances satisfactory to the Planning Board as to the provision for permanent maintenance of the approved minor lane at no expense to the town.
A. 
Design.
(1) 
Basic requirement. Storm drains, culverts, swales, detention basins and related facilities shall be designed to permit the unimpeded flow of all natural watercourses, to ensure adequate drainage at all low points along the streets, to control erosion, to intercept stormwater runoff along streets at intervals reasonably related to the extent and grade of the areas being drained and to control the location, rate and quality of stormwater discharge from the development.
(2) 
System Approach. In dispersed-type subdivisions an "open" drainage approach will normally be appropriate, with roadway design aimed at removing water from paved surfaces continuously rather than at infrequent catch basins or spillways, and using swales and ponding areas in preference to gutters, catch basins and piped stormwater. In other subdivision types, drainage normally will be a "closed" system, with stormwater carried in gutters to system inlets. The Planning Board will consider combinations where applicable, and will consider other options based on the specifics of the particular development plan. No closed drainage systems shall be used on unpaved roads.
(3) 
Design basis.
(a) 
In storm events up to a fifty-year storm, peak flows in downstream drainage facilities and receiving streams and sheet runoff onto adjoining properties shall be no higher following development than prior to development, unless an increase is authorized by the Planning Board, following consultation with the Conservation Commission and consideration of the ability of receiving facilities, wetlands or water bodies to absorb the increase, and the consequences of providing detention capacity. Drainage systems shall be designed based on a ten-year frequency storm, except that detention facilities shall be based on a fifty-year storm, and in a one-hundred-year storm streets shall be inundated not more than six inches deep, and a building site on each building lot shall remain uninundated. Drainage design shall accommodate and account for drainage from foundation drains and cellar sumps.
(b) 
In the Floodplain District, drainage systems shall be designed to reduce exposure to flood hazards.
(4) 
Calculations.
(a) 
Calculation methods and constants shall be as approved by the Williamstown DPW. Computerized calculation methods will be accepted, provided that their data and graphic printout are adequately documented to allow review and evaluation.
(b) 
Except where that is shown to be unrealistic, drainage calculations shall assume all tributary area to be developed as zoned, with stormwater management provisions as required under Chapter 70, Zoning, and this chapter.
B. 
Storm drains.
(1) 
Catch basin and sewer configuration. Where employed, catch basin and storm sewer systems shall be configured as required by Chapter 113, Road Construction Standards.
(2) 
Adjacent property. Proper connections shall be made with any existing drains in adjacent streets or easements where they may exist and prove adequate to accommodate the drainage flow from the subdivision. Subdivision plans indicating piped, channeled or otherwise altered discharge onto property of others shall be allowed only if documentation is provided demonstrating authorization from the property owners involved.
(3) 
Subdrains. Subdrains or interceptor drains are required where necessary to preclude flowage of groundwater threatening to the integrity of the road surface.
C. 
Catch basins and manholes. Catch basins shall be provided with grates installed. Leaching catch basins will not be allowed.
D. 
Detention basins. Where employed, detention basins shall be designed in compliance with the following:
(1) 
Depth and grading. Basin overspill height shall be not less than one foot above the highest water surface projected for the design storm, and shall not exceed five feet above bed elevation. The slope of detention basin walls shall not exceed one foot vertical in three feet horizontal.
(2) 
Base determination.
(a) 
The base of the detention basin shall be a minimum of two feet above the maximum water table as defined by the Town of Williamstown Board of Health regulations. (Deep tests shall be made between February 15 and May 15.)
(b) 
Groundwater level shall be certified by a registered professional engineer. The detention basin base must be entirely below the existing grade, not constructed on fill material.
(3) 
Inflow. Inflow pipe invert shall be high enough that there will not be substantial backwater in the pipe with the detention basin at maximum depth. The downstream end of the inflow pipe shall be suitably protected against scour and shall protect the bed and sides of the basin.
(4) 
Outflow. An outflow drain with trash interceptor shall be provided, with a design assuring that outflow will not exceed existing flows for any event up to the design storm, and that the basin will empty in not more than four days in the design storm. Any outflow pipe shall be not les than six inches in diameter. Outflow invert shall be not less than 0.50 foot above bed elevation. An overflow weir protected against erosion shall be provided for accumulations exceeding those of the design storm.
(5) 
Planting. The basin side slopes and bottom shall be provided with four inches of loam, and seeded.
(6) 
Protection. A four-foot fence or wall shall be constructed around the basin with an eight-foot wide gate for access (may be double four-foot leaf), with lock, and a key shall be provided to the Town of Williamstown. However, if the detention facility has slopes not exceeding one foot vertical to five feet horizontal and a maximum water depth of not more than 2.5 feet, an alternative barrier, such as a hedge, may be allowed.
(7) 
Maintenance. Maintenance of detention facilities and other off-street drainage elements shall be assured at no expense to the town, as provided at § 170-4.6D(2).
E. 
Water Resource Districts. Within Water Resource Districts as established in Chapter 70, Zoning, provisions for contaminant removal shall be made employing detention basins with subsurface drains or perforated risers, oil and grit separator catch basins or other devices where appropriate.
A. 
Installation. All elements of sewers, water pipes, gas lines, telephone, electricity and CATV cable which are to be within the traveled way shall be installed before roadway base course installation.
B. 
Water.
(1) 
Public supply. Whenever feasible, the water supply shall be from a public water supply system. In such cases, the water supply system will be considered adequate only if it meets the standards of § 70-5.2B of Chapter 70, Zoning, as well as applicable state and federal law.
(2) 
System responsibility. If connection to a public water system is proposed but it is determined by the Board that the above standards will not be met in part or all of the subdivision for reasons beyond the reasonable responsibility of the developer, the Board may nevertheless approve the plan subject to a condition that any lot not adequately served shall not be built upon until service has been made adequate.
(3) 
Standards. Water system design, equipment, materials and construction shall meet the Construction Standards of the Williamstown DPW, and Fire District requirements for hydrant location.
(4) 
Dead-end mains. Permanent dead-end water mains shall not normally be allowed. Easements shall be provided where necessary to allow for extension or looping of mains through subsequent development.
C. 
Sewerage.
(1) 
Public system. Where street laterals in subdivision streets could connect by gravity to the town sewerage system, provisions shall be made for town sewerage to serve all lots which potentially can be so served. Extension of existing sewerage will be required at the developer's expense to meet this requirement unless either the Hoosic Water Quality District denies authorization, or connection would require greater expenditures for facilities outside the subdivision and not abutting it than for those within or abutting the subdivision, including house connections, or would require acquisition of easements across property of others.
(2) 
Design. Sewerage system design and construction shall comply with the Construction Standards of the Williamstown DPW, as well as applicable requirements of state and federal law.
D. 
Cable utilities.
(1) 
Wiring. Underground distribution systems shall be provided for any and all utility services, including electrical, telephone and cable television services. Poles and any associated overhead structures, of a design approved by the Planning Board following consultation with the Fire District, shall be provided for streetlighting.
(2) 
Streetlighting. The quantity, type and location of lights within a proposed subdivision shall be subject to Planning Board approval following consultation with the Fire District, and shall be shown on the Street Plan. Streetlighting shall normally be installed at each intersection, cul-de-sac or other road hazard. In village subdivisions light spacing normally shall not exceed 350 feet.
E. 
Floodplain District. In the Floodplain District, as established in Chapter 70, Zoning, all public utilities and facilities, such as gas, electrical and water systems, shall be located and constructed to minimize or eliminate flood damage.
F. 
Utility lanes. The applicant may propose location of some or all utilities in service lanes along rear lot lines if the utility providers involved give written approval to the access and other provisions being made.
A. 
Sidewalks.
(1) 
Requirement. Sidewalks shall be provided on both sides of all streets in village subdivisions. In other subdivision types, sidewalks shall be provided where doing so is determined by the Planning Board to be appropriate in order to preserve or connect with existing sidewalks, to provide safe access to schools or recreation facilities or where unusual conditions require them for safety.
(2) 
Design.
(a) 
Sidewalks shall be five feet in width in village subdivisions, constructed of concrete. Elsewhere where required, sidewalks shall be four feet in width, constructed of bituminous concrete, except where the Board determines that potential use warrants a sidewalk five feet in width or construction of concrete. The sidewalk shall be located as indicated on the cross sections of Chapter 113, Road Construction Standards, but variations may be authorized by the Board to minimize disturbance of vegetation or land forms. Sidewalk ramps conforming to the Construction Standards of the Williamstown DPW shall be provided at all intersections of sidewalks and streets, and elsewhere as appropriate.
(b) 
Any off-street paths shall provide a clear path not less than five feet wide and be within rights-of-way not less than eight feet wide, in both cases unless greater width is required because of the function of the pathway.
(3) 
Construction. Construction shall comply with Chapter 113, Road Construction Standards, of the Williamstown DPW.
B. 
Shoulders. Shoulders shall be provided free of obstructions other than trees approved for preservation by the Board. Width shall be as indicated on the cross sections in Chapter 113, Road Construction Standards.
C. 
Slope areas.
(1) 
Slope limitations. No slopes resulting from grading of streets shall exceed one foot vertical to two feet horizontal, or 3/4 foot vertical to one foot horizontal in ledge. Slope easements for construction shall be provided where regrading cannot be contained within street side lines. Any retaining walls proposed must be located in easements outside of the street right-of-way, with provisions for private maintenance.
(2) 
Stormwater containment. Driveway entrances and land between the outside of the layout and the traveled way shall be so graded as to prevent surface water on the street from draining onto private land except at designated ponding areas or at drainage easements.
D. 
Plantings.
(1) 
Clearing. The site of a project shall only be cleared to the extent necessary for construction or for safe sight distances. Trees, shrubs and ground cover beyond the limits of construction should be preserved whenever possible, and so marked in the field and protected against damage during construction.
(2) 
Stream protection. A strip of vegetation 10 or more feet wide shall be preserved along stream banks to stabilize slopes and protect against erosion.
(3) 
Preserved plant materials. Plant materials which require removal for construction should, when feasible, be salvaged to be replanted at a later time.
(4) 
Ground planting. Unpaved areas within the right-of-way which have been stripped by the construction shall be restored to vegetation, except where stone riprap is necessitated for drainage. That vegetation shall be perennial grasses on at least four inches (after rolling) of topsoil, with methods and materials as specified in Chapter 113, Road Construction Standards. Slopes steeper than 2.5:1, or which do not support turf, shall be planted with vines, ground cover or other low-growing herbaceous or woody plants in addition to grass.
(5) 
Street trees. Tree retention or planting shall provide substantial microclimate protection (shading, wind interruption) for subdivision streets, except where not doing so is approved in advance by the Board in order not to obstruct vistas or because of localized growing conditions. A plan showing location and species of trees proposed for retention or planting to accomplish that shall be submitted to the Board for approval before planting. Where street trees are to be located outside of the right-of-way, an easement shall be provided, giving the town both authority regarding tree planting, maintenance and removal, and responsibility regarding tree maintenance.
(6) 
Tree stock. Trees to be planted as street trees shall be well branched, nursery grown stock at least 21/2 inches trunk diameter at four feet above ground, and shall be free of injury, harmful insects and diseases. Suitability of species must be approved by the Planning Board, taking into consideration the recommendations of the Tree Warden and such published guides as Arnoldia, Volume 39, #3, May/June 1979, and American Standards for Nursery Stock, American Association of Nurserymen, 1990, with considerations as outlined in Appendix C.[1] Planting and maintenance shall follow guidelines of the American Association of Nurserymen.
[1]
Editor's Note: Appendix C is included at the end of this chapter.
(7) 
Existing trees. Existing trees within the right-of-way, if larger than four inches trunk diameter at four feet above ground and located outside the shoulders, shall be preserved, unless removal is authorized by the Planning Board because they are of species unlikely to survive the environmental change, or are diseased, weak or easily broken by wind or snow loads when exposed. Trees to be retained shall be marked in the field, protected as necessary and not have grade changed over their root areas more than 12 inches.
E. 
Street signs. As soon as a street is paved, street signs conforming to those placed by the town shall be erected at all street intersections.
F. 
Monuments. Monuments shall be installed at all street intersections; at all points of change in direction or of curvature of the streets; at each lot corner along the street; and as necessary to locate any easements to be deeded to the town. Materials and construction shall be as provided in Chapter 113, Road Construction Standards.
A. 
Open space.
(1) 
Basic requirement. The Planning Board may require the plan to show a potential park or parks suitably located for recreational purposes or for providing light and air. The park or parks shall not be unreasonable in area in relation to the land being subdivided and to the prospective uses of the land.
(2) 
Reservation. The Board may by appropriate endorsement on the plan require that no building be erected upon such potential park or parks for a period of not more than three years without its approval, which provides a period within which the town or a nonprofit organization has an opportunity to purchase the designated property.
B. 
Earth removal. Any area within the subdivision used for the extraction of gravel or borrow shall be regraded, loamed and in sod before final release is granted by the Planning Board.
C. 
Spoil lots. One or more lots or other designated areas in each subdivision shall be reserved for disposal of stumps and rock resulting from the development of that subdivision, unless the applicant provides a written agreement providing for off-premises disposal at an approved site. Land within the subdivision intended for such use shall be so identified on the subdivision plan, and further indicated on that plan as "not a building lot." Notice that such use has been authorized by the Board of Health shall be posted on the premises until disposal is completed, and all requirements of the Board of Health are complied with, at which point the land shall be restored to safe and stable slopes and grades, and vegetation shall be restored. Such restoration shall be included in the items for which bond or other security is provided, and shall be completed prior to final release of security.
D. 
Maintenance.
(1) 
General. The entire area within the right-of-way shall be properly maintained by the developer or successor organization, such as a homeowners association, until accepted by the town. Immediately prior to such acceptance, all catch basins shall be cleaned, streets swept and the remainder of the right-of-way and any other areas to be deeded to the town shall be cleaned, mowed or otherwise put in first-class order. Snow removal and sanding of the streets shall be the responsibility of the developer or successor organization until such acceptance.[1] Before sale of any lot, the subdivider shall clean up any debris thereon caused by construction of public improvements.
[1]
Editor's Note: See also Art. III, Road Acceptances, of Ch. 60.
(2) 
Permanent responsibilities.
(a) 
Except for minor lane residential development, whose maintenance is provided for in § 170-4.2H(4), when private maintenance of landscaping within streets or off-road detention facilities or street tree easements are entailed, the applicant shall be required to provide assurances, satisfactory to the Planning Board, as to the provision for permanent maintenance of the improvements at no expense to the town.
(b) 
Prior to conveyance of any lots, the applicant shall enter into an agreement with the town to ensure the continued operation and maintenance of those elements cited above without expense to the town.
E. 
Easements.
(1) 
Utility easements. Easements for utilities shall be provided where necessary and shall be at least 20 feet wide.
(2) 
Drainage easements. Where a subdivision is traversed by an intermittent watercourse, drainageway, detention area, channel or stream, there shall be provided a stormwater easement or drainage right-of-way of adequate width to conform substantially to the lines of such watercourse, drainageway, detention area, channel or stream and to provide for construction or other necessary purposes (such as maintenance).
(3) 
Off-site Easements. Drainage easements outside of the area of the subdivision, but occasioned by it, may be required of the subdivider.
(4) 
Slope easements. Slope easements to provide for construction shall be provided where cut or fill slopes cannot be contained within the street right-of-way.
F. 
Erosion control. Erosion control efforts shall be made consistent with the requirements of § 70-5.3C of Chapter 70, Zoning.
G. 
As-built plans. Upon completion of construction, and before release of the performance guaranty, the subdivider shall have prepared and submitted to the Williamstown DPW as-built plans in accordance with Chapter 113, Road Construction Standards.
Provisions shall be made for extension of streets and utilities to adjoining properties, including installation of water gates and manholes, if necessary, unless the Planning Board determines that such extension would not serve the public interest. The developer shall not deny others connection to the water system, sewerage, drainage or cable utilities, provided that those doing the extension receive prior approval of the Williamstown DPW and pay all costs of such connection, and comply with all applicable requirements of the Town of Williamstown.