Subdivision: 4. Infrastructure Requirements

4.01          STREETS

 1.     Overall Layout

 a.     Proposed streets shall be in harmony with existing or proposed thoroughfares as shown on any Plan of Conservation and Development adopted by the Commission, especially with regard to safe intersections within such thoroughfares.

 b.     Proposed streets shall be designed and constructed to provide a safe and convenient system for prospective traffic and for continuation onto adjoining properties when subdivided.

 c.     Proposed streets shall connect to:

 i.     An existing State highway; or

 ii.    An existing City street; or

 iii.  A proposed City street which has been approved by the Commission and for which a financial guarantee is on file with the City in accordance with these Regulations.

 d.     Proposed streets shown on the subdivision plan shall be in harmony with any existing or proposed streets shown in the Plan of Conservation and Development, especially in regard to safe intersections with such streets.

 e.     In general, proposed streets shall be designed to follow the contour of the land with consideration given to preserving natural features and other important resources as identified in Section 3.01 and Section 3.02 of these Regulations.

 f.     All streets within a subdivision shall be completed at the same time in order to service all improved lots except that a subdivision may be developed in sections or phases with separate financial guarantees and/or approval types provided:

 i.     Such sections or phases shall have been shown on the plan; and

 i.    The concept of phasing and the arrangement of the phases shall have been approved by the Commission.

 

 2.     Improvement Of Existing Streets – Where a subdivision is proposed which has frontage on an existing State highway or an existing City street where said existing street does not meet the right-of-way requirements of these Regulations, does not meet the appropriate street requirements or design standards or has a dangerous condition, the Commission:

 a.     Shall require that the applicant dedicate the required right-of-way and any appurtenant slope or other easements to the City along the frontage of the subdivision owned or controlled by the applicant to correct the deficiency; and

 b.     May require that the applicant evaluate and determine the improvements required to meet the appropriate street requirements or design standards or resolve a dangerous condition and propose a resolution wherein the street deficiency will be addressed.

 

 3.     City Street Standards

 a.     The design and surfacing of all streets, roads, facilities and improvements within the public right-of- way shall be undertaken by the applicant in accordance with all City of Groton Public Works Department specifications and said design shall be incorporated into the subdivision plans submitted by the developer for plan approval.

  City Street
Right Of Way Width 50 feet
Pavement Width
  • Where lot sizes or land uses suggest that on-street parking will likely occur
32 feet, except that 26 feet may be permitted on a cul-de-sac street where it is not anticipated such road will be connected to an existing street or extended in the future
  • Where lot sizes or land uses suggest that on-street parking will likely not occur
26 feet, except that 22 feet may be permitted on a cul-de-sac street where it is not anticipated such road will be connected to an existing street or extended in the future
Curbing Concrete curb 6 inches wide and 18 inches deep constructed of 4500 PSI concrete
Street Base Per City of Groton
Street Construction Specifications
Street Surface Per City of Groton
Street Construction Specifications
Minimum Street Grade 1 percent
Maximum Street Grade 10 percent
except that 10% grades may be used for short distances not greater than 500 feet
Cross Slope Crown on the centerline with
¼ inch / foot cross-slope to the gutter

 

 b.     All necessary slope rights and easements shall be acquired by the applicant and dedicated to the City and any exceptions:

 i.     Shall only be under extenuating circumstances; and

 ii.    Shall be specifically approved by the Commission.

 4.     Intersection Design

 a.     Proposed streets shall intersect other streets so that the centerline of the proposed street shall be a straight line for a distance of at least 100 feet from the intersecting street-lines unless otherwise approved by the Commission on the recommendation of the Director of Public Works.

 b.     Intersections between adjoining street lines should be laid out with an angle of approximately 90 degrees, and never less than 60 degrees.

 c.     Multiple streets intersecting at one location shall generally be avoided and, except when the Commission finds conditions are present which justify a variation from these requirements, the centerlines of intersecting streets shall be spaced far enough apart to avoid conflicting movements or unsafe situations.

 d.     Proposed streets shall intersect other streets such that the slope of the travelway on the proposed street shall not exceed two (2) percent within fifty (50) feet of the intersection unless otherwise approved by the Commission on the recommendation of the Director of Public Works.

 e.     Street-lines at intersections shall be connected by a curve having a minimum radius of 25 feet.

 f.     Clear visibility at any proposed intersection shall be provided from a driver’s eye (located at a height of 3.5 feet above the surface of the proposed street and a location twenty feet (20 feet) back from the edge of the travelway of the intersected street) for at least 300 feet measured along the centerline except the Commission may require that an applicant demonstrate that this will result in unobstructed view along both directions of the intersected street that is in conformance with current CTDOT standards for the 85th percentile speed for:

 i.      The “minimum” sight distance.

 ii.    The “desirable” sight distance.

 iii.   Such sight distance shall not be impaired by curvature or slope, except in extreme conditions, in which case adequate alternative safety measures shall be designated.

 

 5.     Cul-De-Sac Street Length Limitation

 a.     Unless otherwise approved by the Commission, no temporary or permanent cul-de-sac street or streets shall serve more than twenty (20) lots or extend more than 1,200 feet from the nearest intersection, whether inside or outside the subdivision, that has two means of access.

 b.     A greater length of a cul-de-sac street may be permitted by the Commission, in its sole discretion, due to adverse topographic or soil conditions, difficult site configuration, future street extension or similar circumstances.

 c.     It is recommended that when an applicant wishes to request approval of cul-de-sac streets with a length greater than 1,200 feet or serving more than 20 lots, the Preliminary Plan procedures established in these Regulations be followed.

 6.     Design of Permanent Turnaround

 a.     A permanent cul-de-sac street shall terminate in a turnaround with:

 i.     A right-of-way that is at least 100 feet in diameter (50 feet in radius), and

 ii.    A paved travelway having an outside diameter of 80 feet (40 feet in radius).

 b.     The right-of-way of such turnaround shall not be located closer than one-hundred (100) feet from the property line of the parcel being subdivided or the minimum lot depth prescribed by the Zoning Regulations, whichever is greater.

 c.     The turnaround shall have a landscaped island at its center unless modified or waived by the Commission and the subdivision plans shall contain a note that the maintenance of such island shall be the responsibility of the abutting landowners and not the City of Groton.

 d.     The turnaround shall not exceed a slope of three percent (3%) measured from the start of the turnaround to its end.

 e.     The Commission may require that pedestrian, drainage and/or utility easements of appropriate width be provided from the terminus to the abutting property line(s).

 7.     Street Extensions and Temporary Cul-De-Sac Streets

 a.     The Commission may require that the arrangement of streets in a subdivision provide for the extension of existing streets and for the future extension of proposed streets into abutting property not yet subdivided.

 b.     The Commission may require the applicant to demonstrate the feasibility and practicality (or the infeasibility or impracticality) of extending the proposed street onto or through adjacent property.

 c.     When any such provision for extension is required by the Commission, the applicant shall provide for access to the adjacent undeveloped land via a City street to the abutting property.

 d.     When any such provision for extension is required and is an extension or continuation of a proposed street, the proposed subdivision street shall:

i.         Have the full width of the right-of-way extended to the property line of the subdivision plus any grading rights required for the future street;

ii.       Have the area of a temporary turnaround brought as close to the boundary as is practical,

iii.      Have a travelway spur extending 10 feet from the turnaround area toward the undeveloped land, and

iv.      Have temporary easements provided to the City, where such easements shall automatically terminate when the street is extended, outside the standard right-of-way for:

a.       The temporary turnaround area; and

b.       Grading associated with the future street extension.

 e.     If the proposed access to abutting property is not an extension or continuation of a proposed street (such as being perpendicular to a proposed street), the applicant shall have:

 i.     The future street area graded with all slopes made necessary by such street prepared and stabilized; and

 ii.    No reserve strips left at the end or side of any access which adjoins abutting property.

 f.     The applicant of the adjoining land shall be responsible for:

 i.     Preparing drawings showing and including all work required to extend, connect and complete the sidewalks, utilities and other improvements between the existing street and the proposed subdivision; and

 ii.    Removing all segments of any temporary turnaround or other temporary improvements outside the normal paved surface and suitably grading and seeding the ground at such time as the street is extended.

 8.     Street Names

 a.     All streets shall be named and proposed street names shall be indicated on the subdivision plan and shall be approved by the Commission.

 b.     Proposed street names shall be selected so as to avoid similarity in spelling or pronunciation with existing public or private street names in the City of Groton or the Town of Groton.

 

 9.     Street Signs and Traffic Controls

 a.     Prior to the issuance of any certificate of occupancy within the subdivision, City acceptance of a City street, or final release of a financial guarantee related to street construction, the applicant shall provide and install at the applicant’s sole cost and expense:

 i.     Suitable traffic control devices and signs in accordance with the standards set forth in the Manual on Uniform Traffic Control Devices; and

 ii.    Suitable permanent street name signs at all street intersections in accordance with City standards.

 b.     During street construction and prior to the issuance of any building permit, temporary street name signs and suitable traffic control devices of a durable, weatherproof material shall be installed by the applicant at street intersections if required by the Department of Public Works.

 

 10.     Other Requirements

 a.     Side slopes shall be designed to assure adequate stabilization and shall not be steeper than one foot (1 foot) vertical to two feet (2 feet) horizontal in earth and in ledge 6 feet vertical and 1 foot horizontal.

 b.     The surface of the travelway shall be centered within the right-of-way.

 c.     During construction:

 i.     All trees and roots shall be stripped to below the base course of the pavement and for the full width of the pavement.

 ii.    All soft spots, peat, organic material, soft clay, spongy soil, boulders and other unsuitable material shall be removed and replaced by material approved by the Director of Public Works.

 iii.   The subgrade shall be rolled with a ten-ton roller before placing the base course.

 d.     Monuments and markers shall be laid out and established in accordance with Section 7.06.

 

 11.     Special Considerations For Non-Residential Subdivisions

 a.     In a non-residential subdivision, the applicant shall demonstrate the street, parcel, and block pattern proposed is specifically adapted to the uses anticipated and takes into account other uses in the vicinity.

 b.     Street rights-of-way and pavement width and thickness shall be adequate to accommodate the type and volume of traffic anticipated to be generated thereupon.

 c.     The applicant shall demonstrate that the design and construction of streets, curbs and sidewalks and the design and installation of public utilities including water, sewer, electric, gas and storm water drainage complies with the standards in these Regulations and the City of Groton Public Works Department specifications.

 d.     Streets carrying non-residential traffic, especially truck traffic, shall not normally be extended to the boundaries of adjacent, existing or potential residential areas.

4.02          SIDEWALKS

1.     Five-foot (5 feet) wide concrete sidewalks are required along both sides of streets except that, on a temporary cul-de-sac street, a sidewalk shall not be required on the area of the temporary turnaround.

2.     The outer edge of the sidewalk shall be set at the street line and this will generally result in a grassed strip between the concrete curbing and the sidewalk.

3.     All concrete sidewalks shall be constructed of 4500 PSI concrete and comply with all City of Groton Public Works Department specifications.

4.     Where a subdivision which has frontage on an existing street is proposed, the applicant shall be required to install sidewalks along said street frontage or bring existing sidewalks up to current City standards.

5.     As part of a subdivision, the applicant may offer and the Commission may accept the extension of an existing sidewalk or the installation of a new sidewalk in lieu of or in addition to the above requirements if doing so would enhance pedestrian accessibility in the general area of the subdivision.

4.03          DRIVEWAYS

1.     Driveways shall be 12 feet wide at the street line.

2.     Wherever feasible, driveways shall be 1½” higher at the streetline than the centerline of the pavement with a 1½” lip at the edge of the pavement.

3.     Each proposed lot shall be served by a driveway with a maximum slope of 15 percent and no Certificate of Occupancy shall be issued unless this requirement is met.

4.     Within the City street right-of-way, no driveway shall be graded such that it would receive drainage from the City street.

5.     The Commission may require driveway locations be shown on the plan to assure proper sight line, proposed slope, drainage and intersection with the street.

6.     The Commission may require a specific driveway location, grade, width, surface or other design requirement in order to provide for reasonable access for emergency and other services.

4.04          SEWAGE

1.     It is the responsibility of the applicant to supply satisfactory evidence to the Commission and the Director of Health that adequate sewage disposal will be provided for each lot and the Commission shall not approve any lot where insufficient evidence has been provided with regard to sewage disposal to satisfy the requirements of the Public Health Code of the State of Connecticut.

 a.     Where the City sewer system is available:

 b.     It shall be utilized; and

 

2.     All sewer mains and laterals within the street right-of-way shall be installed prior to the final surfacing of the street unless otherwise approved by the Director of Public Works.

3.     Where private sewage disposal (a septic system) is to be used, approval by the Director of Health shall be obtained.

4.05          WATER

1.     It is the responsibility of the applicant to supply satisfactory evidence to the Commission and the Director of Health that a potable water supply will be provided for each lot and the Commission shall not approve any lot where insufficient evidence has been provided with regard to water supply to satisfy the requirements of the Public Health Code of the State of Connecticut.

2.     Where a public water supply system is available:

 a.     It shall be utilized;

 d.     Provision shall be made for the installation of water mains and fire hydrants within the proposed development; and

 c.     All water lines and supply connections within the street right-of-way shall be installed prior to the final surfacing of the street unless otherwise approved by the Director of Public Works.

 

3.     In accordance with CGS Section 8-25a, any subdivision using water supplied by a water company incorporated on or after October 1, 1984 shall not be approved unless such company has been issued a certificate pursuant to CGS Section 16-262m.

4.06          FIRE PROTECTION

1.     Each applicant shall provide fire hydrants to protect public safety where required by the Commission based on the recommendation of the Fire Marshal and/or Fire Chief.

4.07          STORM DRAINAGE

 1.     General

 a.     The applicant shall be responsible for constructing adequate facilities for the control, collection, treatment, conveyance and acceptable disposal of storm water, other surface water and subsurface water, whether originating in the subdivision or in a tributary drainage area in order to:

 i.     Minimize degradation of water resources within the City of Groton from pollution from non-point source runoff;

 ii.    Mitigate impacts to the hydrologic system from development, including reduced groundwater recharge and pollutants found in stormwater runoff;

 iii.   Reduce or prevent flooding, stream channel erosion, and/or other negative impacts created by the volume of stormwater runoff resulting from development; and

 iv.   Promote the application of low impact development (LID) strategies for the analysis and design of stormwater treatment systems.

 b.     All drainage facilities shall be designed by an engineer and shall be subject to review by the Director of Public Works and the approval of the Commission.

 c.     The Commission may, at the applicant’s expense, seek independent evaluation of the proposed drainage design.

 

 2.     Low Impact Development

 a.     Curbing, catch basins and pipes shall generally be required to control drainage except that the Commission may accept alternative arrangements (such as vegetated swales and/or other techniques, where appropriate) which demonstrate best management practices for implementation of “green infrastructure” or “low impact development” when appropriate after considering recommendations from the Director of Public Works and other parties designed to implement the following provisions of Chapter 7 of the Connecticut Stormwater Quality (CSQ) Manual (2004), as amended:

 i.     Pollutant Reduction (CSQ Manual Section 7.4).

 ii.    Groundwater Recharge and Runoff Volume Reduction (CSQ Manual Section 7.5).

 iii.   Peak Flow Control (CSQ Manual Section 7.6) for the 10-year, 25-year, and 100-year storm events.

 

 b.     The Commission may, at the applicant’s expense, seek independent evaluation of the proposed drainage design.

 

 3.     Design of Drainage Facilities

 a.     Storm drainage facilities shall be designed and constructed in accordance with CTDOT Construction Standards and Specifications, unless modified by the Commission with the approval of the Director of Public Works.

 b.     Lots shall be laid out so as to provide positive drainage away from all buildings and individual lot drainage shall be coordinated with the general storm drainage pattern for the area.

 c.     Drainage facilities shall be laid out so as to prevent the discharge of water to the City street, including the right-of-way.

 d.     Drainage shall be designed to avoid concentration of storm water from each lot to adjacent lots and shall be shown on the subdivision plan.

 e.     The design and construction of storm drainage facilities shall:

 i.     Be adequate for present and potential future uses based upon the maximum ultimate development of the upstream watershed as permitted under existing Zoning Regulations;

 ii.    Not cause flooding of abutting property from the headwater and backwater produced by bridges, culverts, and other structures;

 iii.   Make proper provision (including easements or manholes) for drainage from development of adjacent properties; and

 

 f.     All drainage design formulas and analyses shall adhere to acceptable engineering practice and the calculations and their method of derivation shall be indicated as part of the application.

 g.     The following information shall be submitted to the Commission:

 i.     Plan showing the catchment areas for each structure;

 ii.    Calculations showing the design criteria used to determine the pipe diameter and other parameters for each pipe length; and

 iii.   Information showing that drainage pipes will provide a self-cleansing velocity of at least 2.5 feet per second when flowing full.

 

 h.     Rainfall intensities used for storm drainage design shall be taken from the U.S. Weather Bureau “Rainfall Intensity – Duration Frequency Curves” for the nearest rain gauge.

 i.      Drainage structures shall be designed to accommodate the following storm frequency:

 i.     A 25-year storm frequency for streets within the subdivision and detention/retention on individual lots (including catch basins, inlets, pipes, underdrains and gutters); and

 ii.    A 100-year storm frequency for culverts, bridges through watercourses, and detention/retention basins.

 

 j.     Catch basins shall be provided so that surface water is not carried across or around any intersection, nor for a distance greater than 200 feet in the gutter.

 k.     When capacity is exceeded at any point, catch basins shall be provided.

 l.     All drainage pipes shall be capable of carrying two inches (2 inches) of rainfall per hour for six (6) hours over the immediate catchment area.

 m.     Catch basins shall have footings and the basins shall be concrete.

 n.     Type “C” grate-and-frame catch basin covers shall be built to State of Connecticut specifications.

 o.     The sump of the catch basin shall have a minimum depth of two feet (2 feet).

 

  4.     Drainage Facilities

 a.     Within the road right-of-way, long diagonal drainage crossings under the pavement that can cause differential street settling shall be avoided. Where a development connects to existing streets, the applicant shall provide appropriate drainage at the intersections.

 b.     Drainage facilities outside of the street right-of-way shall be enclosed in suitable underground pipes wherever desirable.

 c.     Easements for drainage facilities shall be:

 i.     Perpetual, unobstructed drainage easements;

 ii.    At least 20 feet wide;

 iii.   Centered on the pipe and, where possible, centered on property lines; and

 iv.   Deeded to the City of Groton if the drainage facilities serve a City street and deeded to the association if the drainage facilities serve a private street.

 

 d.     Where it is necessary to discharge storm water across private property not included in the subdivision, the applicant shall obtain, in writing, permanent drainage rights in favor of the City for flows across such properties. If the system is to be accepted by the City, the rights for the City to enter and maintain existing or proposed facilities shall be included. The applicant shall submit copies of all agreements to the Commission prior to final approval of the subdivision. Such drainage easements shall be shown on the subdivision plan and filed on the land records.

 e.     The Director of Public Works shall approve the location and spacing of drainage structures, if provided.

 f.     Unless modified by the Commission based on a recommendation of the Director of Public Works, the minimum pipe size for all storm drain systems constructed under these Regulations shall be 15-inch inside diameter.

 g.     The material for all storm drain systems constructed under these Regulations shall be reinforced concrete, except that the Director of Public Works may allow the use of High Density Polyethylene (HDPE) in appropriate circumstances.

 h.     Unless modified by the Director of Public Works, a minimum cover of two (2) feet shall be provided for all storm drains.

 i.     Proper bedding, grading, and cover shall be provided around and for all drainage structures.

 

 5.     Drainage Outlets and Channels

 a.     All storm drain system outlets shall be terminated with an approved outlet structure and stabilized as necessary. Easements for outlet pipes shall extend to a suitable existing storm drain or a natural watercourse. No storm drain system shall discharge into a natural watercourse, without the approval of the Conservation and Inland Wetlands Commission. No storm drain system shall outlet into a natural watercourse, whether continually flowing or intermittent, so as to exceed the capacity of the watercourse.

 b.     A detention basin may be required by the Commission to prevent silting of streams, wetlands, or other areas contiguous to the drainage outfall and/or to reduce the rate of runoff to pre-construction conditions.

 c.     When drainage outlets or channels are required by the Commission for drainage purposes, the applicant shall provide the City with a plan and any required rights-of-way for long-term maintenance.

4.08          WIRE UTILITIES

1.     New electric, telephone, television, cable and other utility wires shall be installed underground unless the Commission determines, based on a written report submitted by the applicant and reviewed by the Director of Public Works, that such underground installation is inappropriate or infeasible for all or a part of the subdivision or resubdivision after considering:

a.     The type of service existing in the area adjacent to the subdivision;

b.     Topographic and construction conditions; and

c.     The size of the subdivision or resubdivision.

 

2.     All pipes and conduits for wire utilities shall be installed:

a.     In the side strips of the right-of-way and outside the paved area wherever possible, and

b.     Prior to final surfacing of the street.

 

3.     Any wire utility located outside of the right-of-way shall be located in an easement adequate in width to allow for present or future connections or extensions of such utilities and for the maintenance thereof.

4.     All wire utilities associated with the subdivision shall be installed at the applicant’s expense prior to issuance of a certificate of occupancy and/or, if a City street, prior to acceptance of the street by the City.

5.     Electric, telephone, cable television, and any other wire utilities shall be installed in proposed and existing streets as specified by the appropriate utility company and shall be subject to the inspection and acceptance of such company and the Director of Public Works.

6.     For a City street, all wire utilities shall be located and mapped on an as-built drawing prior to acceptance of the street by the City.

4.09          STREET LIGHTS

1.     Street lights shall be shown on the subdivision plan in quantity and location sufficient to assure public safety.

2.     The street light pole, fixture, and lamp shall be acceptable to the Commission.

4.10          STREET TREES

1.     Trees shall be planted, to provide shade and to enhance the environment, at approximately fifty foot (50 feet) intervals along the sides of every street abutting lots of the proposed subdivision except where, in the opinion of the Commission, existing trees are to be retained by the developer in sufficient number and location to meet the intent of this section.

2.     New trees shall be nursery grown, free from disease, and treated for bark injuries.

3.     Such trees shall be planted on private property within six feet (6 feet) of the street line.

4.     Determination of precise locations for trees shall consider future possible locations of driveways and utility connections.

5.     The size and species of trees shall be of a type so as to fulfill the purposes of this regulation.

Groton