2.07 Design Standards

1. Purpose. 974 CMR 2.07 sets forth the Design Standards that apply to streets, earth removal, stormwater management, landscape treatment within the street right of way, sidewalks, trails, and street lighting in subdivisions at Devens. There are special requirements for certain Zoning Districts. The general purpose of 974 CMR 2.07 is to ensure that streets are designed with appropriate consideration for the built and natural environment and enhances and protects improvements at Devens.

2. Street Layout and Construction.
   
   (a) All streets shall be continuous and where possible, align with existing streets. All proposed streets shall form a convenient system to allow for full vehicular and pedestrian movement. All intersections shall be at an angle of 90 but not less than 60. Details of street geometry are included in the Table in 974 CMR 2.07.

   (b) Street widenings may be required by the DEC, based upon provision of detailed traffic analysis supporting the need to increase capacity. If a subdivision requires construction of a new street or substantial widening or upgrading of an existing street, then the construction standards summarized in the following table titled Street Design Standards by Classification apply.

   (c) Whether located within the street right-of-way or within easements, water mains shall connect to the Devens water supply system and shall extend to the boundary of the subdivision where there is adjacent undeveloped or developed land using private wells. The system shall be designed to form a continuous loop with existing or proposed water mains. Dead end mains are not permitted.

   (d) Reserve strips prohibiting access to streets or adjoining property are not permitted, except where, in the opinion of the DEC, such strips restrict access in accordance with the public interest.

   (e) Prior to the construction or major upgrading of streets, the right-of-way centerline shall be test bored at locations and depths specified by the Director to determine whether the existing soil can adequately support the street. Where subsurface conditions do not provide an adequate foundation, the Applicant shall detail construction techniques that will be used to ensure the street will be suitably constructed.

   (f) Street signs of the type and character used within Devens and approved by MassDevelopment Engineering bearing the name of the street shall be provided at all intersections and shall be installed when the binder course of the roadway is installed. The DEC shall also require safety and traffic controls signs to be installed by the Applicant.

3. Street Classification. Streets at Devens shall be classified as Lane, Local, Minor Collector or Major Collector (see 974 CMR 2.07: Table). Refer to the Definitions (974 CMR 1.00). In general, however, Major Collectors have the highest vehicular capacity and connect to the entryways (gates) at Devens. Minor Collectors connect to Major Collectors. Local Streets provide the lowest vehicular capacity. Lanes shall be reserved for residential streets serving up to 12 residential units.
   (a) Lanes. A Lane is a street consisting of two travels lanes, each 9 feet wide, with two one-foot shoulders.

   (b) Local Streets. Local Street shall consist of of two travels lanes, each ten feet wide, with a minimum 2 foot paved shoulder. Local street are required for residential streets serving up to 25 residential units.

   (c) Major Collector Streets. A Major Collector street consists of two travel lanes, each 12 feet in width, with two three-foot shoulders. Depending on the level of traffic generated by proposed uses abutting the street, acceleration and deceleration lanes may be required by the DEC.

   A Major Collector Street Alternate is allowed in the districts where a sidewalk is allowed on one side. In these cases, the Applicant may propose a drainage swale in the location of the proposed water main (as indicated on the cross-sectional detail) or within an abutting drainage easement. In this instance, the proposed water main may be constructed beneath the swale, on the road shoulder, or within the travelway. Swale grading, stormwater management, and water resources protection shall conform with the standards of 974 CMR 2.00.

   (d) Minor Collector Streets. A Minor Collector street is composed to two lanes, also 12 feet in width, with two three-foot shoulders. Sidewalks for Minor Collector streets shall also be provided depending on anticipated use. Landscaping is integral to the construction and upgrading of all streets and shall comply with Table 2 and 974 CMR 2.07.

4. Street Design Standards. The following table is the street design standards by street classification. References for minimum design standards in this Table are:
   1. "A Policy on Geometric Design of Highways and Streets" prepared 1990 ("AASHTO");
   2. "Traffic Design Handbook" prepared by the Institute of Transportation Engineers dated 1992; and
   3. "Massachusetts Highway Department Highway Design Manual, July 1989 ("MHD").

Table:
STREET DESIGN STANDARDS BY CLASSIFICATION

5. Stormwater Management.
   (a) Overview: Stormwater Management within subdivisions generally consists of the control of stormwater runoff within the street right of way. It is characterized by common, multiple user drainage collected in the street right of way and directed towards appropriate receptors. MassDevelopment will usually provide or oversee maintenance of these stormwater management systems.

   (b) All Subdivision Plans, regardless of whether the project is subject to the Wetlands Protection Act or not, shall design the stormwater management system in compliance with the goals and objectives of the Massachusetts Department of Environmental Protection Stormwater Management Policy (DEP SMP). to the greatest extent possible given the specific constraints of the land being subdivided. The Applicant shall submit a completed and endorsed Stormwater Management Form (SMF) that indicates compliance to the greatest extent possible, with the SMP's nine (9) Stormwater Management Standards, as most recently amended. The Applicant shall also provide calculations indicating compliance with each standard. Refer to the DEP SMP and its referenced sources for specific application of these stormwater management categories.

   (c)Stormwater Improvements. Drainage calculations prepared by the Applicant's Engineer, including design criteria, pre- and post-drainage areas and other information sufficient for the DEC to verify the size of the proposed drain, swale, drain field, culvert, bridge or catch basin. Said calculations shall be made separately for each drainage facility, showing its location, the total upstream drainage area, the underlying soil types and the flow paths for the times of concentration, the design run-off, facility size, slope and capacity and velocity of water through it. For other requirements, design standards, and criteria, refer to 974 CMR 4.08.

   (d) Stormwater collection systems for subdivisions shall be connected with the overall Devens Stormwater System (DSS). Extensions to the DSS for new roadways shall be approved by the MassDevelopment Engineering Department. Roadway drainage may also be channeled and discharged to improvements located on a remote lot not necessarily owned by any of the parties discharging water. The proper easements to channel, detain and discharge run-off to a remote facility must be created to the satisfaction of the DEC and be declared in favor of the MassDevelopment.

   (e) Drainage systems shall follow the requirements of the Devens Stormwater Pollution Prevention Plan, the Water Resources Protection Report, and the Water Resources Protection By-Law.

   (f) The stormwater management system for the subdivision may be designed and constructed to include drainage and run-off from developed sites as well as the roadway. The Director may require the Applicant to provide a stormwater management plan for the entire subdivision at full build-out to minimize the total number of detention/retention basins. There shall be no negative impact from drainage on abutting properties, nor on any public or private water supply or designated potential future supply.

   (g) Maintenance of Stormwater Improvements in Private Ways. The owners of private ways shall comply with a maintenance schedule as follows:

   1. Biannual inspection by the property owner of detention/retention basins for erosion, debris, sand deposits, and vegetative growth. Vegetation shall be cut back annually, as appropriate, and debris or sediment removed from the basins.

   2. Submission of an annual report to the DEC by the end of February for the proceeding calendar year by the property owner of the detention/retention basin to the DEC indicating that maintenance issues have been adequately addressed and that corrective measures were made where necessary.

6. Landscape Treatment with Streets Rights-of-Way
   (a) Purpose. When a new or substantially upgraded street is constructed, street trees and planting strips are required as part of the right-of-way improvements.

   The landscape treatment is an integral part of the streetscape in Devens. Within the right-of-way it provides visual and climactic relief from broad expanses of pavement and clarify vehicular and pedestrian circulation. The spacing of trees, in combination with other vegetation, walks, lighting, signage, and street furniture, forms a rhythm that provides a sense of progress and creates landmarks for pedestrians.

   (b) Design Standards.

   1. General.
      a. All landscape plans shall, to the greatest extent feasible, maximize the use of indigenous (native) plant material. See below for recommended plant lists.

      b. All plant material shall meet all American National Standards Institute (ANSI) standards for plant material as set forth in Z60.1: American Standard for Nursery Stock, latest edition published by the American Association of Nurseryman. All plant material shall also meet certain standards of quality for form, structure, and health and have a minimum winter hardiness for Zone 5B, as determined by the American Standards for Nursery Stock.

      c. Minimum sizes for plant material, other than for specific uses indicated elsewhere in 974 CMR 2.00, shall be as follows (also see planting standards below):

      i. Deciduous Shade Trees: three-inch caliper

      ii. Deciduous Ornamental Trees: two-inch caliper

      d. Minimum sizes for shrubs/groundcover shall be as indicated below.

   2. Street Trees. The Applicant shall select an appropriate planting pattern for street trees in subdivision.
      (a) single species per street (alternating species required on parallel and perpendicular streets)

      (b) single species between intersections of a single street (alternate species on the same street at intersections only)

      (c) alternate species on either side of the same street, recommended on roads with walks on one side

      (d) multiple species may be used on the same side of any street between intersections only when proposing informal drifts or clusters of trees, whereby each drift or cluster consists of four trees minimum in a staggered layout, consisting of one species per drift. Species may then alternate from drift to drift, using no more than four species on any one street in this fashion.

      (e) Planting Standards. New or substantially upgraded subdivision roads within each Zoning District shall be planted with street trees. Trees shall be planted on both sides of the street, maximum spacing shall be 50' o.c. Street trees may be clustered or grouped together with 25' maximum on-center within a drift, with 75' maximum distance between clusters.

      (f) Tree Species. The Applicant shall utilize indigenous plant material to the greatest extent feasible. Street trees are listed in 974 CMR 3.05(5).

   3. Groundplane Treatment.
      (a) All unpaved areas within the street right-of-way shall pitch at 1:50 minimum.

      (b) All unpaved areas within the right-of-way with a gradient between 1:50 and 1:3 shall be lawn. Grass shall be sod, seed, or hydroseed using species mix composition typically used in New England for grass receiving routine mowing.

      (c) Any unpaved areas within the right-of-way between 1:3 and 1:1.5 shall be planted with low shrubs (under three feet height at maturity) or groundcover, having fibrous root systems to control erosion.

   4. Shrubs.

      The following list of native shrub species is recommended for their high performance in slope stabilization, urban, and roadside conditions. Substitutions must be able to demonstrate suitability to the satisfaction of the DEC.

      Botanical Name	Common Name	Minimum Installed Size	Maximum Spacing on-center for Min Size
      Cornus sericea 'Kelseyi'	Kelsey Dwarf Red Osier Dogwood	12" - 15"	18" o.c.
      Ilex verticillata 'Nana'	Dwarf Winterberry	18" - 24"	2' o.c.
      Rhus aromatica 'Gro-low'	Dwarf Fragrant Sumac	15" - 18"	18" o.c.
      Vaccinium angustifolium	Lowbush Blueberry	1 gal	2' o.c.

      In addition, the following list of non-native species is recommended for high performance in bank stabilization, urban, and roadside conditions. Substitutions must be able to demonstrate suitability to the satisfaction of the DEC.

      Botanical Name	Common Name	Minimum Installed Size	Maximum Spacing on-center for Minimum Size
      Cotoneaster horizontalis	Rockspray	18" - 24"	2' o.c.
      Hedera helix'Baltica'	Baltic Ivy	2 yr.	8" o.c.
      Juniperus chinensis sargentii	Sargent Juniper	18" - 24"	2' o.c.
      Juniperus horizontalis varieties	Creeping Juniper	18" - 24"	2' o.c.
      Lonicera japonica 'Halliana'	Hall's Honeysuckle	2 yr.	18" o.c.
      Rosa rugosa 'Max Graf' Rose	'Max Graf' Rugose	1 gal	2' o.c.
      Rosa rugosa 'Repens'	Dwarf Rugose Rose	1 gal	2' o.c.
      Spiraea bumalda 'Anthony Waterer'	Anthony Waterer Spirea	18" - 24"	2' o.c.
      Vinca minor	Periwinkle	2 yr.	8" o.c.

      g. Slopes created to meet existing grades within or immediately adjacent to the Right-of-way shall not be greater than 1:1.5. Where space is limited or nearby existing trees/woodland are being retained, the Applicant shall provide retaining walls to avoid slopes steeper than 1:1.5.

      i. Retaining walls under four feet retaining height shall be mortared fieldstone wall construction with dry-laid look, brick, or flat face "lock blocks" in a natural stone color acceptable to the DEC.

      ii. Retaining walls four feet height or greater shall be concrete with a fieldstone or brick veneer, or flat face "lock blocks" in a natural stone color acceptable to the DEC.

      h. Within the Rail, Industrial, and Trade Related District and the Environmental Business District only, the use of trap rock for bank stabilization may be substituted in the place of the recommended shrubs. Proposed retaining walls may be concrete.

   5. Existing Vegetation.
      a. Vertical alignment of roads and sidewalks running through areas of undisturbed woodland or mature trees shall follow the existing topography to the greatest extent feasible to reduce the impact to undisturbed woodland within and adjacent to the right-of-way.

      b. Topographic alteration and the removal of vegetation beyond the limits of the proposed right-of-way shall be kept to the minimum possible extent to meet existing grades, and to the maximum feasible extent shall lie within the proposed right-of-way.

      c. Vegetation shall be cleared from the right-of-way only as needed to accommodate roadway, utilities, and sidewalks.

      d. Significant trees (12" caliper +) or woodland vegetation outside the roadbed within the right-of-way shall be preserved by adjusting the alignment of utilities and walkways to avoid the trees. The Applicant shall provide tree wells for any grade change of six inches above or below existing finish grade within six feet of the trunk of a tree to be preserved. Use of dry laid fieldstone construction for tree wells is encouraged.

      e. All work within the root zone of existing trees to be preserved shall be carried out under the direction and supervision of a certified arborist.

   6. Sidewalks.
      (a) Objectives.
      1. Sidewalks into the right-of-way of subdivision streets are intended to support and enhance safe pedestrian circulation by providing a separate, dedicated pedestrian path, thereby reducing potential conflict with vehicular and bicycle circulation occurring within the roadbed.

      2. Each sidewalk installed within the right-of-way of a subdivision road shall contribute to an overall network of sidewalks that ultimately will become a continuous and predictable system of walkways offering safe connections from any combination of pedestrian generators and destinations within the Enterprise Zone.

      3. All sidewalks within the right-of-way of a subdivision road shall support and enhance the concept of universal accessibility.

      (b) Design Standards.
      1. All sidewalks and crosswalks shall conform to the Massachusetts Architectural Access Board (521 CMR) requirements, as most recently amended.

      2. All sidewalks shall be constructed to a Minimum Standard or a Higher Standard. Design Criteria for each standard is as follows:

      a. Minimum Standard is generally used in areas with lower levels of pedestrian traffic and where appearance is typically of less importance. Sidewalks shall be constructed of bituminous concrete, 4'-0" minimum width, and shall comply with the dimensions and specifications of the sidewalk details of 974 CMR 2.00.

      Generally, minimum standard sidewalks shall be constructed in the Rail-Related District, the Environmental Business District, and the Special Use II District. In the Innovation Technology Business District and the Gateway I and II Districts, minimum standard sidewalks shall be constructed along Minor Collector roadways, while higher standard sidewalks shall be constructed along Major Collector streets.

      b. Higher Standard Sidewalks are generally used in areas with relatively high levels of pedestrian traffic. Sidewalks shall be constructed of concrete, 4'-0" minimum width (5'-0" in the Business/Community Services District), and shall comply with the dimensions and specifications of the sidewalk details of 974 CMR 2.00. Higher standard sidewalks shall be constructed in the Innovation Technology Center District, Business/Community Services District, Village Growth I and II Districts, Residential I and Residential II Districts, and Special Use I. In the Innovation Technology Business District and the Gateway I and II Districts, higher standard sidewalks shall be constructed along Major Collector roadways.

      3. Uses that generate particularly high levels of pedestrian activity, such as schools, transit stops and places of public assembly shall have sidewalks constructed of concrete with 7'-0" minimum width across the entire lot frontage and paved to the back or inner side of the curb. The DEC may allow a lesser width (but in no instance less than 4'-0") or sidewalks along a portion of the frontage, if the DEC finds adequate pedestrian access and safety will be provided.

   7. Lighting.
      (a) Design Standards.
      1. All lighting shall conform to 974 CMR 4.00.

      2. The light source is recommended by the DEC to be metal halide. Substitution may be allowed at the discretion of the DEC.

      3. Collector roads shall have light poles at 30' height maximum to the top of the light fixture/ post assembly, with 75' maximum spacing.

      4. Local Roads shall have light poles at 18' maximum height to the top of the fixture/post assembly with 50' maximum on-center spacing.

      (b) Fixture Style.
      1. Within all districts (except Environmental Business, and Rail, Industrial and Trade Related Districts and the Historic District overlay) the following fixture shall be used exclusively:

         (to be determined)

      2. Within the Environmental Business and Rail, Industrial and Trade Related Districts, the following fixture shall be used exclusively:

         (to be determined)

      3. Within the Historic District overlay, streetlight fixtures and poles shall comply with the Report: Street Lighting Recommendation for Devens Historic Overlay District prepared by Carol R. Johnson and Associates of Boston, MA dated November 30, 2001.

   8. Trails - When a portion of the public trail system as shown on the Devens Main Post Trails report dated July 2001 and any amendments thereto adopted by the DEC falls within the locus of the land to be subdivided, the Applicant shall construct that portion of the trail on the lot. The trail detail is shown as 974 CMR 3.06 (12) Figure L. Depending on the size and use of a proposed subdivision, DEC may require connectors to the main trail system in addition to or in lieu of sidewalks.