A. 
The subdivider shall observe all design standards for land subdivision as hereinafter provided. These standards shall be considered minimum standards and shall be varied from or waived only as provided in Article 6. All subdivisions shall be designed and improvements made by the applicant consistent with the requirements of Articles 4 and 5. Refer also to Article 6 of these rules and regulations for additional design and construction standards.
B. 
Design and construction shall reduce, to the extent reasonably possible, the following:
(1) 
Volume of cut and fill;
(2) 
Area over which existing vegetation will be disturbed, especially on land within 200 feet of a river, pond, or stream, or having a slope of more than 15%;
(3) 
Number of mature trees removed;
(4) 
Visual prominence of man-made elements which are not necessary for safety or orientation;
(5) 
Visibility of building sites from existing streets;
(6) 
Blockage of vistas through new development;
(7) 
Removal of existing stone walls;
(8) 
Number of driveways exiting onto existing streets or collector roads;
(9) 
Alteration in groundwater or surface water levels or chemical constituents;
(10) 
Disturbance of important wildlife habitats, outstanding botanical features, or scenic or historic environs;
(11) 
Soil loss or instability during and after construction.
C. 
Design and construction shall increase, to the extent reasonably possible, the following:
(1) 
Configuration using collector streets to avoid traffic on streets providing house frontages;
(2) 
Visual prominence of natural features of the landscape;
(3) 
Street layout facilitation of solar orientation of houses;
(4) 
Use of curvilinear patterns.
D. 
Referenced standard. A Policy on Geometric Design of Highways and Streets, by the American Association of State Highway and Transportation Officials (AASHTO), latest edition, as amended.
The subdivision shall be in conformity with the respective zoning requirements and the general layout shall harmonize and conform to plans for Norfolk, as adopted by the Planning Board.
No lot area or width in a subdivision shall be less than the minimum required by the Zoning Bylaw for the district in which it is located.
A. 
In case access to subdivision crosses land in another municipality, the Board shall 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. 
If a proposed subdivision encompasses the Town of Norfolk and an adjoining town, at least one point of access must be provided in the Town of Norfolk.
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.
In case a tract is subdivided into larger parcels than ordinary building lots or if a subdivision is adjacent to a tract capable of subdivision, such parcels and streets shall be arranged so as to allow the logical and economic extension of streets, utility easements, drainageways, and public areas into such parcels and adjacent tracts.
The resubdivision of all or part of land covered by an existing plan shall be governed by these regulations. Such resubdivision shall show clearly that area or areas which are being replatted and shall show the file number of all previous plans of these same areas with dates of filing.
In general, block lengths shall not be less than 300 feet nor more than 2,000 feet.
The deeds of all lots containing easements whose purpose is access to and/or maintenance of surface or subsurface features shall clearly state that no permanent plantings or structures, including but not limited to buildings, driveways, and fences, shall be installed within such easements. No barriers to the maintenance of drainage structures are allowed.
A. 
Layout. Wherever possible, easements shall be continuous from block to block and their layout shall create as few irregularities as possible. The minimum easement width shall be 20 feet, except that tree easements, if necessary, shall not be less than 10 feet (see Subsection D) and certain easements for pedestrian walkways shall not be less than five feet (see § 325-4.10).
B. 
Watercourses. Streams or watercourses shall be provided with an emergency/maintenance access easement conforming substantially with the average high-water mark of its course, but in no case less than 20 feet in width centered on its midpoint. Parallel streets or pedestrianways and/or appropriate access may be required in connection therewith. The placement of streams or watercourses into open or covered culverts shall be kept to a minimum.
C. 
Utilities.
(1) 
Easements for utilities across lots shall generally follow lot lines or shall be centered on the rear or side lot lines and shall not be less than 20 feet in width.
(2) 
Easements for utilities along roads shall follow and be outside of the right-of-way lines and shall be not less than five feet in width.
D. 
Trees. Trees shall be located within the grass strip of the street right-of-way. However, in cases where the Planning Board determines that it is preferable to locate them outside the right-of-way, tree easements shall follow and be outside of the right-of-way lines and shall be 10 feet in width. Trees shall be planted at forty-foot or lesser intervals on both sides of all streets. The applicant shall show the location and species of trees on the subdivision plan at the time of submittal. (See also § 325-5.9.)
A. 
Pedestrianways or footpaths shall be required to provide convenient circulation or access to schools, playgrounds, shopping, churches, transportation, parks, conservation areas and/or other facilities. If not within a street right-of-way, such ways shall consist of an easement of at least 20 feet wide, except that walkways shall consist of an easement of at least five feet wide.
B. 
Walkways shall be required on the applicant's property along the entire frontage (from side line to side line) of all existing public ways which immediately abut the proposed subdivision as well as all proposed public ways for the purpose of assuring safe and adequate pedestrian access to, from and within the subdivision.
C. 
To facilitate review of the proposed plan by the appropriate authorities, the applicant shall stake the side line of the proposed walkways along existing roadways at fifty-foot intervals.
D. 
See also § 325-5.2J for construction details.
The Planning Board may require that a subdivision plan show a park or parks suitably located to serve the future residents of the subdivision for playground or recreation purposes or for providing light and air and not unreasonable in area in relation to the area of the land being subdivided and the prospective uses of such land.
A. 
If such a park or parks is required, the subdivision plan shall include an appropriate endorsement requiring that no building may be erected on such site for three years without the approval of the Planning Board.
B. 
Any open space park or playground shall provide at least 50 feet of continuous frontage on a street, and pedestrianways will normally be required to provide access from each of the surrounding streets, if any, to which the open space, park or playground has no frontage. Further, such parks and/or playgrounds shall be required to have maintenance provided for by covenants and agreements acceptable to the Board, until public acquisition by the community.
C. 
Land designated for park or playground purposes shall not include wetlands, ledge, or other lands unsuitable for recreation purposes.
A. 
Due 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.
B. 
Prior to the removal of any trees over four inches in diameter in the right-of-way and within any tree easement and prior to grading, the developer shall mark all trees proposed for removal and the developer shall plot these marked trees on the plan. All trees except those approved for removal by the Planning Board shall be protected against construction damage. The grade below these trees shall be retained as necessary in order to ensure their preservation, including the use of tree wells, where necessary.
A. 
All buildings in a subdivision or other structures therein intended for human occupancy and all fire hydrants shall be connected to and served by the Town water supply system, as available or as extended at the expense of the developer of the subdivision.
B. 
The definitive plans shall indicate the existing and proposed locations of all water lines, including their type, size, and class. All proposed valves and fittings shall be located on the plans and identified by its station. Proposed valves shall be located so that they line up with the edge of traveled way, gutter line, or street line. The existing nearest hydrant(s) to the development shall be located on the plans. Hydrants shall be located at all low points, and hydrants or manual air-release valves shall be located at all high points of the proposed water mains.
A. 
Arrangement. The proposed streets shall be considered in their relation to existing and planned streets, topographic and geologic conditions, public convenience and safety, and for safe vehicular travel. Due consideration shall also be given by the developer to the attractiveness of the street layout in order to obtain the maximum amenity of the subdivision and to avoid excessive cut and fills. Long, straight roadway sections should be avoided. The maximum length of a straight segment on a residential or secondary street shall be 500 feet. In addition, the proposed streets shall provide for appropriate continuation and connection of existing primary and secondary streets, and the extension of primary and secondary streets onto adjoining land.
B. 
Access to primary streets and through streets.
(1) 
Intersections of secondary and residential streets with primary streets will not be allowed with offsets between intersections of less than 350 feet whether on the same or opposite sides of the primary or through street.
(2) 
Subdivisions, and extensions to subdivisions, including or capable of including 25 lots or more shall have at least two points of access to an existing through street separated by a minimum distance of 350 feet or shall have two separate passable access routes via existing primary street(s) to an existing through street where the points of access are.
C. 
Reconstruction of adjacent public ways. In cases where the development of a subdivision may cause congestion or a danger to pedestrian or vehicular traffic on the adjacent public ways, remedial measures satisfactory to the Planning Board may be required. Such measures may include, but are not limited to, the addition of alternate access roads or reconstruction of the adjacent public ways.
D. 
Street jogs. Street jogs (i.e., the continuation of a street through an intersection where the center line of the paved surface is not aligned on both sides of the intersection) are prohibited.
E. 
Reverse curves. Reverse curves on streets may be separated by a straight section of road of at least 150 feet in length if a street has a design speed of 30 miles per hour or less. This can be addressed on a case-by-case basis during the plan review process to ensure that public safety is not impacted.
F. 
Right-of-way widths and alignments. On all classifications of streets, the characteristics as shown in the following chart titled "Right-of-Way Widths and Alignments Based on Design Speed" shall be the minimum acceptable (see also Figures 31 to 34).[1]
Right of Way Widths and Alignments Based on Design Speed
Street Classification
Residential
Secondary
Primary
Design speed (miles per hour)
20
25
30
Minimum curb to curb (feet)
24
26
28
Minimum right-of-way (feet)
50
60
60
Minimum curb radius at intersections (feet) [1]
20
20
25
Minimum traveled way center-line radius (feet) no superelevation
90
170
280
Traveled way coincident with center line
Not required
Not required
Required
Stopping sight distance (feet) [2]
125
150
200
Intersection sight distance (feet) [2]
200
340
400
Minimum intersection spacing center line to center line (feet)
350
350
350
Two-way traffic volume ADT/DHV
<400/<200
<800/<300
<800/<400
Minimum grade
1%
1%
1%
Maximum grade
10%
8%
6%
Sight Distance Summary
85th Percentile Speed
(miles per hour)
Stopping Sight Distance
(feet)
Corner Sight Distance
(feet)
35
225 to 250
390
40
275 to 325
445
45
325 to 400
500
50
400 to 475
555
55
450 to 550
610
60
525 to 600
665
65
650 to 725
720
70
625 to 800
775
[1]
The intersection of roads with differing design speeds shall be designed in accordance with § 325-4.14G(2).
[2]
For design purposes, sight distances shall be based on the 85th percentile speed, which is the speed below which 85% of the vehicles are traveling.
[3]
At intersections where the gradient exceeds 3%, a leveling area of not less than 100 feet is required. Refer to § 325-4.14H(3).
[1]
Editor's Note: Figures 31 to 34 can be obtained from the Planning Board office.
G. 
Intersections.
(1) 
Rights-of-way shall be laid out so as to intersect as nearly as possible at right angles. No right-of-way shall intersect any other right-of-way at less than 75°. Intersections of existing and proposed streets will not be allowed at intervals of less than 350 feet between center lines.
(2) 
Property lines at right-of-way intersections shall provide for a curb radius on the roadway as indicated in Subsection F, Right-of-way widths and alignments. The curb radius at the intersection shall be as required by Subsection F and shall be sufficient to accommodate "WB-50" vehicle turning movements. In instances where streets of differing design speeds intersect, the smaller curb radius requirement shall be required.
(3) 
In instances where there are state roadways involved, the curb radius required by state regulations shall be provided. The state-required radius is not required to be paved, but rather, the difference in area between the state and local radii requirements shall be provided in the form of granite rubble block pavement, as indicated in Figure 35.[2]
[2]
Editor's Note: Figure 35 can be obtained from the Planning Board office.
(4) 
Both the horizontal and vertical sight distance and stopping sight distance at intersecting roadways within a subdivision and at subdivision roadways intersecting with existing roadways shall be provided as indicated in Subsection F, Right-of-way widths and alignments.
(5) 
Horizontal and vertical stopping sight distances in all directions at existing and proposed intersections shall be noted on the plans.
H. 
Vertical alignment.
(1) 
All changes in grade shall be connected by vertical curves of sufficient length to afford adequate sight distances as indicated in the following chart:
Design Speed
(miles per hour)
Stopping Sight Distance
(feet)
20
125
25
150
30
200
(2) 
Vertical curves.
(a) 
For crest vertical curves, the length in feet shall be computed from the following formulas:
When S is less than L, L = {AS2} OVER {100{(SQRT (2h SUB 1) + SQRT (2h SUB 2)) SUP 2}}
When S is greater than L, L = 2S - {200 (SQRT h SUB 1 + SQRT h SUB 2) SUP 2} OVER {A}
Where:
L
=
Length of vertical curvature
S
=
Sight distance
A
=
Algebraic difference in grades, percent
h1
=
3.50 feet (eye of driver)
h2
=
2.0 feet (height of object)
(b) 
For sag vertical curves, the length in feet shall be computed from the following formulas:
When S is less than L, L = {AS SUP 2} OVER {400 + 3.5S}
When S is greater than L, L = 2S - {400 + 3.5S} OVER {A}
Where:
L
=
Length of vertical curvature
S
=
Sight distance
A
=
Algebraic difference in grades, percent
(c) 
Minimum length of a sag or crest vertical curve shall be 100 feet. All vertical curves shall show the following on the profiles:
[1] 
Point of vertical intersection (PVI) station and elevation.
[2] 
High point or low point station and elevation.
(3) 
The grade of any proposed street meeting another existing or proposed street within or adjacent to the subdivision shall not exceed 2% for a distance of not less than 100 feet, measured from the nearest edge of right-of-way of the other street.
I. 
Culs-de-sac.
(1) 
The paved portion of culs-de-sac, whether temporary or permanent, shall not be less than 250 feet in length and not exceed 500 feet in length measured from the intersection (center line) of the nearest intersecting through street to the farthest end of the paved turnaround, and shall not provide access to more than seven lots.
(2) 
Culs-de-sac, whether permanent or temporary, shall provide a turnaround at the closed end(s) having a property line diameter of 120 feet, a radius at the outer edge of traveled way of 47 feet, and a landscaped island in the center having a maximum radius of 15 feet. Islands shall be designed to allow for proper emergency vehicle and snowplow access. A "not a through street" sign shall be provided at the entrance to a cul-de-sac and its location shown on the subdivision plan. In the case of a temporary turnaround, the plan shall show an easement(s) to accommodate the specifications of this subsection. The frontage of lots abutting a temporary turnaround shall be measured along the permanent street right-of-way and not the "bulb" of the cul-de-sac. See detail (Figure 43).[3] Any easement in any turnaround shown on a plan approved under the Subdivision Control Law,[4] other than an easement appurtenant to a lot abutting the turnaround, shall terminate following the approval and recording of a plan showing extension of the roadway and the recording of a certificate by the Planning Board of the construction of such extension.
[3]
Editor's Note: Figure 43 can be obtained from the Planning Board office.
[4]
Editor's Note: See MGL c. 41, §§ 81K through 81GG.
(3) 
Provisions for future through access.
(a) 
All culs-de-sac, except those determined by the Planning Board to be permanent in nature, shall include a right-of-way running from the closed end(s) of the cul-de-sac to the terminus points as described below for purposes of providing future through access. The width of said right-of-way shall be equal to the right-of-way width of the cul-de-sac street. Said right-of-way shall be laid out and construction plans included as part of the subdivision plan. The land in the right-of-way shall be turned over to the Town of Norfolk as a gift of land prior to release of any lot in the subdivision.
(b) 
The terminus point of the right-of-way shall be both to any adjacent Town-owned conservation land and as follows:
[1] 
First, to any street which abuts the property line of the parcel being subdivided, other than the street which forms the intersection with the paved portion of the cul-de-sac;
[2] 
Second, if Subsection I(3)(b)[1] is not applicable, to any right-of-way or street easement of at least 20 feet right-of-way width which abuts the property line of the parcel being subdivided;
[3] 
Third, if Subsection I(3)(b)[1] and [2] are not applicable, to the point on the property line of the parcel being subdivided which is closest to the closed end of any cul-de-sac existing on any adjacent parcel;
[4] 
Fourth, if Subsection I(3)(b)[1], [2] and [3] are not applicable, to the point on the property line of the parcel being subdivided which is closest to any existing through street on any adjacent parcel, other than the street which forms the intersection with the parcel portion of the cul-de-sac;
[5] 
Fifth, if Subsection I(3)(b)[1], [2], [3] and [4] are not applicable, to the point on the property line of the parcel being subdivided which is closest to any adjacent landlocked (i.e., without adequate frontage) parcel; and
[6] 
Sixth, if Subsection I(3)(b)[1], [2], [3], [4] and [5] are not applicable, to the point on the property line of the parcel being subdivided which is closest to the largest adjacent buildable parcel of land.
(c) 
For purposes of this regulation, references to the point "closest" shall exclude wetlands. The easement created by this subsection shall, to the extent practicable, be laid out to exclude lakes, ponds, wetlands, woodlands, watercourses and steep terrain.
(4) 
An easement for access and maintenance shall also be provided from all culs-de-sac to any adjacent Town-owned conservation land. Such easements shall have a minimum width of 20 feet.
(5) 
The surface slope of the traveled way within the turnaround required under Subsection I(2) shall not exceed 4%.
(6) 
Cul-de-sac plantings.
(a) 
The applicant shall submit a landscape plan for the central portion of a cul-de-sac. The following are permitted:
[1] 
Trees.
[2] 
Planting with ground cover and spreading mulch between plants for weed control.
[3] 
Planting perennial grass by either sod or seed.
[4] 
Planting ornamental shrubs of a type acceptable to the Board.
[5] 
Retaining existing vegetation with the approval of the Board.
(b) 
The standards of the American Nursery and Landscape Association and the specifications of the Massachusetts Association of Landscape Professionals shall apply to landscaping subject to these regulations.
[Amended 10-11-2022]
J. 
Half streets. A "half street" is a portion of a proposed street running astride a common boundary line, said portion being within a subdivision under consideration. Half streets shall be prohibited.
K. 
Sight distances at intersections. Horizontal and vertical sight distances in all directions at intersections shall be noted on the plans. Sight distances at intersections shall be provided as indicated in Subsection F, Right-of-way widths and alignments.
L. 
Stopping sight distance. Stopping sight distance is the sum of two distances: the distance traversed by the vehicle from the instant the driver sights an object necessitating a stop to the instant the brakes are applied and the distance required to stop the vehicle from the instant brake application begins. For all stopping sight distance calculations, the height of the driver's eye is considered to be 3.5 feet above the road surface and the height of the object is considered to be 2.0 feet above the road surface in accordance with AASHTO policy. Stopping sight distances shall be provided as indicated in Subsection F, Right-of-way widths and alignments.
Excavated cuts shall have a maximum slope of three horizontal to one vertical; cut slopes greater than 15 feet in height shall be benched and approved by the Board.
Driveway locations shall be shown on the plan. All driveways shall be designed and constructed starting from the gutter line. The slope of the driveway shall be upwards toward the sidewalk to be constructed or to a point allowing for a sidewalk to be constructed in the future. Sloping driveways downward towards the right-of-way line is prohibited. A detail and cross section of the proposed driveway shall be indicated on the plans. See driveway detail in "Town of Norfolk Regulations for Street Excavations," as most recently amended.
A. 
Cross sections shall be drawn for all proposed roadways and existing roadways to be reconstructed. They shall be drawn at fifty-foot stations and at all proposed culverts at a scale of eight feet to the inch horizontally and vertically.
B. 
Sufficient space is to be provided between cross sections to allow the proposed roadway template to be drawn without overlapping the adjoining sections.
C. 
The following shall be shown on the sections:
(1) 
Edges of existing roads, drives, walks, bordering vegetated wetlands, lawns, etc.
(2) 
Existing walls, poles, hydrants, mail boxes, etc.
(3) 
All existing trees 12 inches and over noting the diameter, species of tree, station and offset.
(4) 
Elevation, station, and description of wells, cesspools, and on-site septic systems, and a description and elevation of sills of buildings.
(5) 
Existing culverts shall be shown as long dashed lines.
(6) 
Water elevations shall be shown as a dashed line with elevation and date taken.
(7) 
Approximate elevation of the top of rock for above and below existing grade.
(8) 
The profile grade is to be noted on each template. The template shall consist of the finished grade and the proposed subgrade line baseline, and right-of-way lines.
(9) 
Stations shall be located below the cross section and increase going up the plan sheet.
(a) 
Guide vertical elevations and horizontal distances in both directions shall be shown on each cross section.
(b) 
A summary table shall be shown with the cross sections showing the cubic yards between the stations for cut, fill, muck excavation, and rock excavation, and gravel borrow. A total for each category shall be shown along with the final amount of cubic yards of earth to be removed from the site or gravel borrow to be brought into the site.
(10) 
Limits of rock and muck excavation.
(11) 
Planimeter readings are to be shown to the right of each template using the abbreviations C = Cut, F = Fill, M = Muck Excavation, R = Rock Excavation, GB = Gravel Borrow.
A. 
Walkways shall be required on the applicant's property along all existing public ways which immediately abut the proposed subdivision for the purpose of assuring safe and adequate pedestrian access to and from the subdivision. Sidewalks shall not be interrupted by steps or abrupt changes in level greater than 1/2 inch.
B. 
In general, walkways on existing roadway (layouts) shall be constructed with minimum change to the natural rural appearance of the street. Walkways shall follow the natural contours of the land and preserve both trees and shrubs to the extent possible to comply with the guidelines in § 325-5.2J.
C. 
To facilitate review of the proposed plan by the appropriate authorities, the applicant shall stake the side line of the proposed walkway at fifty-foot intervals.
D. 
The width of the walkway shall be five feet minimum. Where such a walk cannot be constructed respecting the existing contours and natural features of the land such as trees, shrubs, stone walls, etc., a minimum width of three feet shall be allowed with prior written approval of the Planning Board.
A. 
General.
(1) 
The stormwater management system shall collect, convey, treat, and recharge stormwater in a manner which will ensure protection of property, preservation of water resources, minimization of environmental impacts, and protection of public and environmental health by providing adequate protection against pollution, flooding, siltation and other problems caused by poor drainage. The stormwater management system shall comply with the following:
(a) 
Adhere to standard engineering practice.
(b) 
Conform to the stormwater management standards of Subsection C.
(c) 
Conform to the current edition of the Massachusetts Department of Environmental Protection's "Massachusetts Stormwater Handbook."
(d) 
Maintain predevelopment drainage patterns and predevelopment hydrological conditions in groundwater and surface waters as nearly as possible.
(e) 
Include a strategy for source control and best management practices (BMPs).
(f) 
Recharge runoff from pervious surfaces.
(g) 
Recharge roof water in separate facilities.
(h) 
Provide treatment train for the water quality volume that reduces the contaminant burden in stormwater to the maximum extent possible (MEP) using best management practices (BMPs).
(i) 
Maintain or enhance surface water quality and groundwater quality.
(j) 
Protect or enhance resource areas subject to regulation under the Massachusetts Wetlands Protection Act (MGL c. 131, § 40) (WPA).
(k) 
Utilize low-impact design where practicable.
(l) 
Collect and convey surface water for applicable design storms.
(m) 
Avoid any increase in the peak rate or volume of stormwater discharge at the property boundary for each storm event specified hereinafter.
(n) 
Implement an operation and maintenance (O&M) plan that complies with DEP guidelines and ensures proper function of the stormwater management system and provides an acceptable future maintenance burden.
(o) 
Provide a sufficient level of health and environmental protection during construction.
(2) 
Refer to the construction requirements, standards and requirements of § 325-5.3.
B. 
Submissions. Design of the stormwater management system shall be prepared by a Massachusetts registered professional engineer and all submitted plans, calculations, and reports shall bear the engineer's signature and seal. Deep hole observations shall be conducted under the direction of a Massachusetts licensed soil evaluator. Submissions shall comply with the minimum content requirements as set forth hereinafter:
(1) 
Plans, profiles, and sections conforming to the requirements of these rules and regulations showing the stormwater management system and existing and proposed buildings, surface grades, surface treatments, and utilities.
(2) 
A stormwater management report, including calculations and a detailed narrative describing predevelopment and post-development conditions, the design and function of the stormwater management system, and the procedures and methods used for analysis.
(3) 
Predevelopment and post-development watershed plans showing existing and proposed buildings, surface grades, surface treatments, catch basins and culverts, watercourses, watershed and catchment boundaries, flow lines, Natural Resources Conservation Service (NRCS) soil boundaries and hydrologic soil groups.
(4) 
Pipe flow calculations based upon the Rational Formula, providing pipe diameter, inverts, slope, velocity (flowing full), length, capacity, design flow, and v/c ratio.
(5) 
Stormwater basin design calculations shall be provided based upon TR-20.
(6) 
Logs of soil borings or deep observation holes.
(7) 
Soil permeability test data.
(8) 
Groundwater monitoring data.
(9) 
Plans showing the limits of all resource areas subject to regulation under the WPA based upon a field survey of points established pursuant to an order of resource area delineation or an order of conditions issued within two years of the date of submission.
(10) 
An operation and maintenance plan.
(11) 
Organization documents for the party responsible for operation and maintenance of the stormwater management system which shall include details of the mechanism used to provide funding in perpetuity.
C. 
Standards. The stormwater management system shall comply with the standards set forth hereinafter (and more fully defined in the current version of the Massachusetts Stormwater Handbook).
(1) 
Standard 1. No new stormwater conveyances (e.g., outfalls) may discharge untreated stormwater directly to or cause erosion in wetlands or waters of the Town of Norfolk.
(2) 
Standard 2. Stormwater management systems shall be designed so that post-development peak discharge rates do not exceed predevelopment peak discharge rates.
(3) 
Standard 3. Loss of annual recharge to groundwater shall be eliminated or minimized through the use of infiltration measures, including environmentally sensitive site design, low-impact development techniques, stormwater best management practices and good operation and maintenance. At a minimum, the annual recharge from the post-development site shall approximate the annual recharge from the predevelopment conditions based on soil type. This standard is met when the stormwater management system is designed to infiltrate the required recharge volume as determined in accordance with the Massachusetts Stormwater Handbook.
(4) 
Standard 4. Stormwater management systems shall be designed to remove 80% of the average annual post-construction load of total suspended solids (TSS). This standard is met when:
(a) 
Suitable practices for source control and pollution prevention are identified in a long-term pollution prevention plan and thereafter are implemented and maintained;
(b) 
Structural stormwater best management practices are sized to capture the required water quality volume determined in accordance with Massachusetts Stormwater Handbook; and
(c) 
Pretreatment is provided in accordance with the Massachusetts Stormwater Handbook.
(5) 
Standard 5. For land uses with higher potential pollutant loads, source control and pollution prevention shall be implemented in accordance with the Massachusetts Stormwater Handbook to eliminate or reduce the discharge of stormwater runoff from such land uses to the maximum extent practicable. If through source control and/or pollution prevention all land uses with higher potential pollutant loads cannot be completely protected from exposure to rain, snow, snow melt and stormwater runoff, the proponent shall use the specific structural stormwater BMPs as provided in the Massachusetts Stormwater Handbook. Stormwater discharges from land uses with higher potential pollutant loads shall also comply with the requirements of the Massachusetts Clean Waters Act, MGL c. 21, §§ 26 through 53, and the regulations promulgated thereunder at 314 CMR 3.00, 314 CMR 4.00 and 314 CMR 5.00.
(6) 
Standard 6. Stormwater discharges within the Zone II or Interim Wellhead Protection Area of a public water supply and stormwater discharges near or to any other critical area require the use of the specific source control and pollution prevention measures and the specific structural stormwater best management practices determined by the Department to be suitable for managing discharges to such area as provided in the Massachusetts Stormwater Handbook. A discharge is near a critical area if there is a strong likelihood of a significant impact occurring to said area, taking into account site-specific factors. Stormwater discharges to outstanding resource waters and special resource waters shall be removed and set back from the receiving water or wetland and receive the highest and best practical method of treatment. A "stormwater discharge" as defined in 314 CMR 3.04(2)(a)1 or (b) to an outstanding resource water or special resource water shall comply with 314 CMR 3.00 and 314 CMR 4.00. Stormwater discharges to a Zone I or Zone A are prohibited, unless essential to the operation of the public water supply.
(7) 
Standard 7. A redevelopment project is required to meet the following stormwater management standards only to the maximum extent practicable: Standard 2, Standard 3, and the pretreatment and structural stormwater best management practice requirements of Standards 4, 5 and 6. Existing stormwater discharges shall comply with Standard 1 only to the maximum extent practicable. A redevelopment project shall also comply with all other requirements of the stormwater management standards and improve existing conditions.
(8) 
Standard 8. A plan to control construction related impacts including erosion, sedimentation and other pollutant sources during construction and land disturbance activities (construction period erosion, sedimentation and pollution prevention plan) shall be developed and implemented.
(9) 
Standard 9. A long-term operation and maintenance plan shall be developed and implemented to ensure that the stormwater management system functions as designed.
(10) 
Standard 10. All illicit discharges to the stormwater management system are prohibited.
D. 
Geotechnical testing.
(1) 
Soil borings logs shall be provided to classify soils within proposed surface stormwater basins and subsurface absorption systems and throughout the drainage study area. Logs of deep observation holes shall be provided within surface stormwater basins and subsurface absorption systems; a minimum of one deep observation hole log shall be provided for each 5,000 square feet of basin area or a minimum of two soil logs per basin, whichever is greater. One boring shall extend to impervious strata or to refusal. The other boring shall extend to the elevation of the design bottom elevation of the basin and shall be used to perform a bore hole permeability test. Additional soil boring or deep observation hole logs shall be provided to classify soils throughout the drainage study area, particularly in locations where available Natural Resources Conservation Service mapping is indeterminate or classifies soils as Udorthents.
[Amended 10-11-2022]
(2) 
In situ field bore hole permeability test data shall be provided within surface stormwater basins and subsurface absorption systems; a minimum of one permeability test shall be provided for each location. For larger surface stormwater basins and subsurface absorption systems, additional permeability tests may be required as determined by the Board. Permeability testing shall be witnessed by the Board of Health agent or the Planning Board agent. If permeability testing is desired to be performed in soils of low permeability, laboratory tests for hydraulic conductivity shall be performed on undisturbed samples by the Falling Head Permeability Test using flexible membrane triaxial test cells with back pressure (U.S. Army Corps of Engineers Engineering Manual EM 1110-2-1906, Appendix VII).
(3) 
A minimum of one monitoring well shall be installed within each stormwater basin. Monitoring wells shall extend to a depth of 10 feet below existing grade or four feet below the design elevation of the bottom of the stormwater basin whichever is deeper. The elevation of groundwater shall be recorded by a Massachusetts licensed soil evaluator, professional engineer, or professional land surveyor once in each of four months. When observations are taken during the months of May through December, the design groundwater elevation shall be adjusted to reflect spring high groundwater conditions using the Frimpter Method.
E. 
Hydrologic analysis.
(1) 
The drainage study area shall encompass the project site and all tributary upgradient areas. The boundary of the drainage study area and the analysis points shall be the same for the predevelopment condition and the post-development condition.
(a) 
Predevelopment and post-development plans of the drainage study area shall show existing and proposed buildings, paved areas, and surface treatment for all open areas. The plans shall show existing and proposed elevations based upon one-foot contour intervals. The plans shall show existing and proposed catch basins and culverts, watercourses, watershed and catchment boundaries, and flow lines, Natural Resources Conservation Service (NRCS) soil boundaries and hydrologic soil groups.
(b) 
Times of concentration shall be determined based upon distance, slopes, and surface materials. A minimum time of concentration to be uses shall be 0.1 hour.
(2) 
Pipe flow calculations shall be provided for the closed drain system based upon the Rational Formula as follows:
(a) 
Rational Formula.
Q = CiA
Where:
Q
=
Peak rate of flow
C
=
Coefficient of runoff
i
=
Rainfall intensity in inches per hour
A
=
Area of watershed in acres
(b) 
A weighted coefficient of runoff "C" is to be determined for each incremented drainage area based on the following minimum values:
[1] 
Roofs and pavement: 0.90.
[2] 
Lawns, flat (2% maximum), sandy soil: 0.10.
[3] 
Lawns, average (2% to 7%), sandy soil: 0.12.
[4] 
Lawns, steep (>7%), sandy soil: 0.18.
[5] 
Lawns, flat (2% maximum), heavy soil: 0.15.
[6] 
Lawns, average (2% to 7%), heavy soil: 0.20.
[7] 
Lawns, steep (>7%), heavy soil: 0.30.
[8] 
Woodland: 0.20.
[9] 
Wetlands, ponds, basins: 0.90.
(c) 
Rainfall intensity.
(3) 
Inlets shall provide capacity to accommodate the design storm. Spread shall not encroach on travel lanes of streets or the top of curbs or berms.
(4) 
Stormwater basin analysis shall be based upon Technical Release 20 (TR-20) as follows:
(a) 
Rainfall.
[1] 
Two-year-frequency storm event: 3.2 inches.
[2] 
Ten-year-frequency storm event: 4.8 inches.
[3] 
Twenty-five-year-frequency storm event: 5.5 inches.
[4] 
Fifty-year-frequency storm event: 6.2 inches.
[5] 
One-hundred-year-frequency storm event: 6.8 inches.
(b) 
Curve number (CN). Weighted curve numbers shall be calculated using the following values. For cover types not stated, refer to TR-20.
Hydrologic soils group
A
B
C
D
Lawns, poor
68
79
86
89
Lawns, fair
49
69
79
84
Lawns, good
39
61
74
80
Impervious areas, pavement, roofs
98
98
98
98
Woods, poor
45
66
77
83
Woods, fair
36
60
73
79
Woods, good
30
55
70
77
Wetlands, ponds, basins
8
98
98
8
(c) 
Curve numbers for conditions not included in the above shall be obtained from TR-20 documentation.
F. 
Design storms.
(1) 
Stormwater runoff shall be analyzed for the two-year-frequency storm event, ten-year-frequency storm event, twenty-five-year-frequency storm event, fifty-year-frequency storm event, and 100-year-frequency storm event.
(2) 
The design storm for all components of the closed stormwater collection system, including catch basin grates and other inlets, drain lines, and the bypass capacity of separator structures, is the twenty-five-year-frequency storm event.
(3) 
The design storm for cross culverts and devices protecting occupied buildings is the 100-year-frequency storm event.
(4) 
The design storm for surface stormwater basins and subsurface absorption systems is the 100-year-frequency storm event. The runoff for design of surfaces providing sheet flow, swales, and drainage ditches that convey runoff to surface stormwater basins and subsurface absorption systems is the excess runoff resulting from storm events greater than the twenty-five-year-frequency storm event but less than the 100-year-frequency storm event.
(5) 
The required recharge volume is the volume resulting from multiplying the factors set forth below times the total post-development impervious surface within the project area for each Natural Resources Conservation Service Hydrologic Soil Group as set forth hereinafter.
[Amended 10-11-2022]
Hydrologic Soil Group
Required Recharge
HSG A Soil
0.60 inch of runoff
HSG B Soil
0.35 inch of runoff
HSG C Soil
0.25 inch of runoff
HSG D Soil
0.10 inch of runoff
(6) 
The water quality volume to be treated is 1.0 inch of runoff multiplied by the total post-development impervious surface within the project area for discharges to critical areas and 0.5 inch of runoff multiplied by the total post-development impervious surface within the project area for discharges to all other areas. Discharges to critical areas include systems accommodating runoff from land uses with higher potential pollutant loads, discharges to areas with infiltration rates greater than 2.4 inches per hour, and discharges to a designated Zone II.
G. 
Design criteria.
(1) 
The closed stormwater collection system shall accommodate the design storm without surcharging and shall provide a free discharge to stormwater basins above the maximum 100-year storm elevation. All components of the system shall accommodate the design storm, including catch basin grates and other inlets, drain lines, and the bypass components of water quality structures.
(a) 
Cross culverts and devices protecting occupied buildings shall accommodate the design storm event without surcharging.
(b) 
Surface stormwater basins and subsurface absorption systems shall have the volume to accommodate runoff providing for no increase in the peak rate of discharge or the volume of discharge at the project boundary for the two-year-frequency storm event, ten-year-frequency storm event, twenty-five-year-frequency storm event, fifty-year-frequency storm event, and 100-year-frequency storm event. Base flow from under drains shall be included in the design flow. Inflow volume shall not be decreased based upon runoff captured by roof water recharge systems.
(c) 
Surfaces providing sheet flow, swales, and drainage ditches conveying excess runoff to surface stormwater basins and subsurface absorption systems shall accommodate runoff from storm events exceeding the capacity of the closed stormwater collection system but less than the 100-year-frequency storm event.
(d) 
Recharge facilities accommodating runoff from paved surfaces shall be provided over broad areas of the site and shall recharge the design storm within 72 hours following cessation of precipitation. Separate roof water recharge facilities shall be provided in proximity to the building served to promote recharge over broad areas of the site and shall recharge the design storm within 72 hours following cessation of precipitation. Recharge facilities accommodating runoff from paved surfaces in combination with recharge facilities accommodating runoff from building roofs shall accommodate the required recharge volume.
(e) 
Water quality components shall be provided to remove 80% of the total suspended solids (TSS) for the water quality volume. Water quality components include deep catch basin sumps, water quality structures, and sediment forebays.
(f) 
Water quality components shall abate phosphorous loadings in stormwater in accordance with the Massachusetts Stormwater Handbook.
(g) 
Inflows and outflows across the project boundary shall be maintained. There shall be no concentration of flow at any point on the project boundary unless a downgradient easement is provided extending to an existing watercourse or wetland.
(h) 
There shall be no new point source discharge within 100 feet of a bordering vegetated wetland. Surface stormwater basins and subsurface absorption systems shall not be located within bordering vegetated wetlands. Stormwater basin discharges shall be above any 100-year jurisdictional flood elevation. Surface stormwater basins and subsurface absorption systems shall not be located within floodplains unless compensatory storage is provided.
(2) 
The closed stormwater collection system shall consist of precast concrete drain manholes, precast concrete catch basins, and precast concrete water quality structures connected by straight segments of drain line.
(a) 
Cross culverts shall consist of straight segments of Class IV reinforced concrete pipe with gasketed joints.
(b) 
The velocity of drain lines shall be determined based upon Manning's equation:
1.486 V = n R2/3 S1/2
Where:
V is the cross-sectional average velocity (ft/s)
k is a conversion constant equal to 1.486 for U.S. customary units
n is the Manning coefficient of roughness (independent of units)
R is the hydraulic radius (feet)
S is the slope of the drain line (feet/foot)
(c) 
The capacity of drain lines shall be based upon the discharge formula:
Q = AV
Where:
Q is the volume of flow in cubic feet per second
A is the cross-section area of the pipe
V is the cross-sectional average velocity (ft/s)
(d) 
The coefficient of roughness (Manning's n) for reinforced concrete pipe shall be 0.013 and for smooth interior wall high-density polyethylene (HDPE) pipe shall be 0.012.
(e) 
The minimum velocity (flowing full) for all drain lines shall be 2.5 feet per second and the maximum velocity (flowing full) shall be 12.0 feet per second flowing full.
(f) 
Drain lines shall be Class IV reinforced concrete pipe with O-ring seal joints conforming to ASTM C443. Corrugated polyethylene pipe with smooth interior walls conforming to AASHTO M294, Type S with O-ring seal joints may be used outside streets for systems that will remain forever private. The minimum pipe size shall be 12 inches in diameter. In instances where pipe diameter increases, the change shall be provided at a manhole and the crown of the inflow pipe shall match the crown of the outflow pipe.
(g) 
Catch basins shall be five-foot inside diameter and shall have a minimum four-foot-deep sump. Catch basins shall be provided at intervals not to exceed 300 feet on center.
(h) 
Separator structures having capacity to treat the water quality volume shall be provided upgradient of all surface stormwater basins and subsurface absorption systems and shall have a bypass capability for larger storms. Separator structures must accommodate cleaning with a clamshell bucket. Separator structures requiring use of a vacuum hose for cleaning shall not be used.
(i) 
Pipe shall have the structural strength to accommodate depth of bury or surface loads. All drainage structures shall accommodate AASHTO SH20-44 loadings.
(3) 
Roof water recharge systems, surface stormwater basins and subsurface absorption systems be located in areas of permeable soil where there is a minimum of four feet of naturally occurring permeable soil between the bottom of the separate roof water recharge system, surface stormwater basin, or subsurface recharge system and impervious soils or bedrock. A minimum separation of two feet shall be provided the bottom of the separate roof water recharge system, surface stormwater basin, or subsurface recharge system and seasonal high groundwater. Design infiltration rates for roof water recharge systems, surface stormwater basins and subsurface absorption systems shall be either the value obtained from permeability tests of Subsection D or the values set forth in the following table, whichever is less.
Table 2-1 Infiltration Rates for Various Soil Textures 2
Texture Class
NRCS Hydrologic Soils Group
Design Infiltration Rate
(inches per hour)
Sand
A
8.27
Loamy sand
A
2.41
Sandy loam
B
1.02
Loam
B
0.27
Silt loam
C
0.52
Sandy clay loam
C
0.17
Clay loam
D
0.09
Silty clay loam
D
0.06
Sandy clay
D
0.05
Silty clay
D
0.04
Clay
D
0.02
(4) 
Separate roof water recharge systems shall be provided, having sufficient volume to accommodate one inch of runoff from roofs. Roof water recharge systems shall be located in areas of permeable soil. Where roof water recharge facilities are located within hydrologic soils group (HSG) D soils, dry wells at the same elevation interconnected with equalizing pipes or linear systems of galleys shall be used.
(5) 
Surface stormwater basins.
(a) 
Surface stormwater basins, including retention basins, detention basins, and basins providing both retention and detention, shall be designed with the following objectives to be considered: hydraulic function, safety, maintenance, aesthetics, and when required, water quality.
(b) 
Surface stormwater basin(s) shall be designed for aesthetics as well as function by proving a naturalistic free-form layout and attractive plantings.
(c) 
Surface stormwater basins may be designed as detention basins, retention basins, or combined detention/retention basins, provided that the design requirement that there be no increase in the peak rate of stormwater discharge and no increase in the volume of stormwater discharge at the property line is achieved by the overall stormwater management system. All detention basins, retention basins, or combined detention/retention basins shall be located in areas of pervious soil and shall be designed to empty such that the required design volume is available within 72 hours following the cessation of precipitation.
(d) 
The design elevation of the bottom of the basins shall be set to provide a minimum two-foot separation between the bottom of the basin and spring high groundwater. A minimum of four or more feet of naturally occurring permeable soil shall be provided between the bottom of the basin and impervious soil or bedrock.
(e) 
Details of inlet and outlet control structures and the infiltration system at the bottom of the basin shall be provided.
(f) 
One foot of freeboard shall be provided above the 100-year design elevation of the basin.
(g) 
An emergency spillway above the 100-year design elevation of the basin shall be provided for all basins that provides an unencumbered hydraulic connection and directs excess flow in a manner that avoids damage to public and private property and wetland resource areas.
(h) 
Stormwater basin side slopes shall have a maximum slope of a three horizontal to one vertical. The Board reserves the right to limit the depth of basins to the twenty-five-year design water surface to four feet maximum. The Board reserves the right to require forty-two-inch-high nonclimbable fencing surrounding the basin for safety based upon the nature of on-site and neighboring land uses.
(i) 
Basin embankments having a height of greater than four feet between the required freeboard elevation and finished grade exterior to the basin shall require geotechnical testing and an embankment design prepared by a Massachusetts geotechnical professional engineer. Sections through such embankments shall be provided and shall show slopes, impervious cores, and surface armoring.
(j) 
Infiltration systems within detention/retention basins are required in the bottom of basins. Frames and grates shall be placed six inches above the basin floor to allow sediment to settle.
(k) 
Surface stormwater basins, including surrounding maintenance access berms, shall be provided on separate lots not part of any building lot. A ten-foot-wide minimum access and maintenance easement shall extend from the public way to the stormwater basin lot.
(l) 
A vehicle-accessible level berm for maintenance access shall be provided, surrounding each surface retention/detention basin or underground leaching structure. The level berm shall extend for a minimum of 15 feet (or the width recommended in the current edition of the Massachusetts Stormwater Handbook if greater) beyond the required freeboard line on the side slope of surface retention/detention basins and 15 feet beyond the structure or distribution piping of underground leaching basins.
(m) 
Security fencing or other effective measures shall be provided surrounding surface stormwater basins and subsurface absorption systems. Guardrail shall be provided for basins in proximity to vehicular areas.
(n) 
To facilitate screening of the stormwater basin, a tree easement having a minimum width of 10 feet shall be provided around surface stormwater basins and subsurface absorption systems located adjacent to and outside the vehicle accessible level berm. Required plantings within the tree easement consist of evergreen trees planted at a maximum of 15 feet on center in each row. Two rows are required that are staggered to enhance screening. A single row of evergreen shrubs having minimum height of six feet at maturity shall surround the trees. Trees shall be spruce or fir and have a minimum height of eight feet in height at the time of planting.
(o) 
The edge of surface stormwater basins shall be measured at the required freeboard elevation. Surface stormwater basins shall comply with minimum setbacks as follows:
[1] 
Property lines: 25 feet.
[2] 
Front setback: 100 feet.
[3] 
Slab on grade buildings: 25 feet.
[4] 
Building cellars or basements: 100 feet.
[5] 
Street intersections: 200 feet.
(6) 
Subsurface recharge systems.
(a) 
Subsurface absorption systems shall be designed with the following objectives to be considered: hydraulic function, safety, and maintenance.
(b) 
Subsurface absorption systems shall meet the design requirement that there be no increase in the peak rate of stormwater discharge and no increase in the volume of stormwater discharge at the property line. All subsurface absorption systems shall be located in areas of pervious soil and shall be designed to empty such that the required design volume is available within 72 hours following the cessation of precipitation.
(c) 
The design elevation of the bottom of the system shall be set to provide a minimum two-foot separation between the bottom of the basin and spring high groundwater. A minimum of four or more feet of naturally occurring permeable soil shall be provided between the bottom of the basin and impervious soil or bedrock.
(d) 
An emergency overflow shall be provided for all systems that directs excess flow in a manner that avoids damage to public and private property and wetland resource areas.
(e) 
Subsurface absorption systems shall consist of precast concrete structures capable of supporting HS20-44 loadings. High-density polyethylene (HDPE) recharge systems capable of supporting HS20-44 loadings may be used for systems that will remain forever private. Subsurface absorption systems shall be embedded in a minimum one-foot-thick layer of double-washed 3/4 inch to 1 1/2 inch stone on the top and sides. The top and sides of the stone shall be surrounded by filter fabric.
(f) 
The treatment train shall provide for 80% total suspended solids removal prior to inflow into the subsurface absorption system.
(g) 
Subsurface absorption systems serving land subdivisions shall be provided on separate lots not part of any building lot. A ten-foot-wide minimum access and maintenance easement shall extend from the public way to the stormwater basin lot.
(h) 
To facilitate maintenance, each structure shall be provided with a twenty-four-inch diameter frame and cover adjusted to finished grade at the inlet and outlet. Additional access covers shall be provided such that no portion of any subsurface recharge systems shall be more than 40 feet from an access cover.
(i) 
The edge of subsurface absorption systems shall be measured at the outer edge of washed stone or the outer wall of the recharge structure, whichever extends further outward. Subsurface absorption facilities shall comply with minimum setbacks as follows:
[1] 
Property lines: 25 feet
[2] 
Slab on grade buildings: 25 feet
[3] 
Building cellars or basements: 100 feet
H. 
Mounding.
(1) 
A mounding analysis is required when the vertical separation from the bottom of an exfiltration system to seasonal high groundwater is less than four feet and the recharge system is proposed to attenuate the peak discharge from a ten-year or higher twenty-four-hour storm. The mounding analysis must demonstrate that the required recharge volume is fully dewatered within 72 hours. The mounding analysis must also show that the groundwater mound that forms under the recharge system will not break out above the land or increase the water elevation in bordering vegetated wetlands or open water areas within the seventy-two-hour evaluation period.
(2) 
A mounding analysis is also required when recharge is proposed at or adjacent to a site classified as contaminated, that was capped in place, or that has an activity and use limitation (AUL) that precludes inducing runoff to the groundwater, pursuant to MGL c. 21E and the Massachusetts Contingency Plan, 310 CMR 40.00; or is a solid waste landfill pursuant to 310 CMR 19.00; or groundwater from the recharge location flows directly toward a solid waste landfill or MGL c. 21E site. In this case, the mounding analysis must determine whether infiltration of the required recharge volume will cause or contribute to groundwater contamination.
(3) 
The Hantush (Hantush 1967; see reference for Standard 3) or other equivalent method may be used to conduct the mounding analysis; however, the Planning Board may require use of a numeric model for larger systems or where required to accurately model groundwater conditions.
I. 
Off-site discharge.
(1) 
In instances where no lots can be developed within a subdivision because no naturally occurring soils are found within the project site which would allow recharge of stormwater within 72 hours, the applicant may petition to allow off-site discharge of stormwater. The Planning Board may waive applicable requirements of § 325-4.19, provided that after due consideration, waiver of strict compliance with the provisions of § 325-4.19 is in the public interest.
(2) 
Runoff may be conveyed to surface stormwater basins or subsurface absorption systems on contiguous properties that fully the off-site surface stormwater basins or subsurface absorption systems have sufficient capacity to attenuate the increase in peak rate and volume. The hydrologic analysis shall establish a design point at the outlet of the surface stormwater basins or subsurface absorption systems. Permanent easements shall be furnished, encompassing all off-site stormwater management facilities and providing proper access for maintenance.
(3) 
Runoff may be discharged to the municipal storm drain system, provided that the off-site connection conforms to the requirements set forth herein. Detention basins are provided on the project site having sufficient capacity to limit the post-development peak rate of stormwater discharge to the municipal system such that it is no greater than the predevelopment peak rate of stormwater discharge to the municipal system. Any increase in the volume of stormwater runoff discharged to the municipal storm drain system will not cause erosion or increase flooding or ponding of water in a manner that would damage properties or wetland resource areas. All off-site components of the receiving municipal storm drain system shall have sufficient excess capacity such that they can accommodate runoff from the project site, plus all runoff from full build out of all properties in its existing service area for the twenty-five-year-frequency storm event without surcharging. The Board of Selectmen may allow the connection and may as a condition of allowing the connection impose a user fee to be paid by the applicant.
A. 
Purpose:
(1) 
To establish a uniform system of numbering primary buildings.
(2) 
To promote efficiency in locating primary buildings.
(3) 
To provide more expedient emergency response.
(4) 
To provide a consistent system to establish mailing addresses.
(5) 
To identify the locations and names of all streets and roads in the Town of Norfolk.
B. 
Properties affected. All primary buildings within the boundaries of the Town of Norfolk shall hereafter be identified by reference to the uniform numbering system. This section shall not apply to the display of date-of-origin numbers for historic buildings, provided that they are displayed so as not to be confused with the assigned street numbers.
C. 
Numbering system. The uniform numbering system has been developed for all primary buildings based on the following process:
(1) 
For purposes of establishing street numbers, a "street" shall be considered any accessway, whether private or public, which serves two or more primary buildings or building lots.
(2) 
The starting point of each street is generally determined by the proximity of its starting point to a main Town road. The sequence of numbers advances as the street proceeds from its designated starting point.
(3) 
All primary buildings on the left side of the street will have odd numbers.
(4) 
All primary buildings on the right side of the street will have even numbers.
(5) 
One odd and one even number will be assigned to each fifty-foot interval of road frontage. Possible exceptions to this rule include densely developed or subdivided areas where numbers will be assigned on the basis of existing parcel configuration and/or development, and in rural areas where the interval may be greater than 50 feet as determined by the Planning Board or agent.
(6) 
If a primary building has several possible numbers due to extensive road frontage or frontage on more than one road, the assigned number will be based on where the driveway intersects with the street.
(7) 
Unused numbers will be held for future use to ensure against the need for renumbering.
(8) 
Duplexes, multifamily complexes, mobile home parks, shopping centers, malls, condominiums, and cottage colonies shall be assigned only one number to the primary entrance onto the street. Units shall be internally numbered according to a logical pattern and manner as approved by the Planning Board.
(9) 
Corner lots shall be assigned the appropriate street number which corresponds to the street from which the driveway originates.
(10) 
Street names and building numbers shall be approved by the Planning Board and other appropriate state and local agencies.
(11) 
All primary buildings must display a numerical address as required by Chapter 134, Buildings, Numbering of, of the Town of Norfolk bylaws, as amended.
D. 
New buildings and subdivisions.
(1) 
Whenever a primary structure or occupied structure shall be erected or located in the Town of Norfolk, designated numbers shall be affixed upon said structure as provided by Chapter 134 of the Norfolk bylaws and this section. Within 90 days after commencement of the construction of a primary structure, the assigned street number shall be posted so as to be clearly visible from the street. Temporary numbers may be used until permanent numbers are posted consistent with Chapter 134. Temporary numbers shall be replaced as soon as practicable.
(2) 
Every subdivision or site plan submitted to the Planning Board for final approval shall show a street or building number of each lot, unit or structure as applicable. These numbers shall be reviewed and approved by the Planning Board or agent and shall be filed with the office of the Tax Assessor consistent with § 134-6.
E. 
Penalty.
(1) 
Any property owner who fails to comply with any provision of this section within 60 days of notification shall be subject to a penalty as specified in Chapter 134.
(2) 
Any property owner who affixes upon a structure any number other than that assigned to, or pursuant to, this section shall be subject to a penalty of $250.
F. 
Administration. Administration is performed by the Planning Board.