Utility and street improvements shall be provided by the subdivider
in accordance with the standards and requirements described hereinafter.
The standards contained hereinafter shall be considered as minimum
requirements, and nothing contained herein shall be construed to imply
that the subdivider cannot construct or provide improvements of a
higher quality.
A. The developer shall provide permanent reference monuments along the
side of street rights-of-way and reference pins along the side of
any easement.
B. Monument specifications.
(1) Permanent monuments shall be of stone or reinforced concrete four
inches by four inches by 48 inches, with a drill hole in the center,
set in such a manner so that they will not be disengaged by frost;
if of concrete, the mix shall be Class A.
[Amended 7-27-2021]
(2) All reference pins shall be of ferrous metal, 1/2 inch in diameter
or larger and a minimum of 24 inches in length. The pin may be solid,
hollow, round, square or any other standard configuration normally
used by surveyors. The pin shall be driven into the ground and shall
not protrude above the ground surface more than 1 1/2 inches.
[Amended 9-8-1987; 1-24-2012]
A. General. In general, all new streets within the subdivision and all
work to be undertaken thereon shall be designed and constructed according
to the specifications adopted by the New Hampshire Department of Transportation.
All plans for such improvements shall be submitted for approval or
approval with modifications to the City Engineer.
B. Grading roadway and side slopes. The roadway and side slopes thereof
shall be considered as part of a site's improvements and, as such,
shall be constructed substantially in accordance with the street cross-sectional
design standards. Side slopes shall not exceed one foot vertical rise
per every two feet of horizontal length without retaining structure
or other special considerations. If the depth of fill is over five
feet, the contractor may be required to perform certain operations
to ensure that major settlement will occur prior to continuing construction.
C. All backfill in trenches and fill for roadbeds shall be thoroughly
compacted to 95% of optimum density, unless otherwise specified in
the approval specifications. All compaction is subject to testing
by the City Engineer or designee.
D. Street construction standards. All streets within the jurisdictional
authority of the City, with the exception of state highways, shall
be improved in accordance with the following minimum criteria and
shall further be arranged and constructed in accordance with the provisions
set forth hereinafter:
(1) Base course.
(a)
The depth of the base course shall be as shown on the standard
road cross section.
(b)
Base course shall not be constructed during freezing weather
or on a wet or frozen subgrade. Blading and rolling shall be required
to provide a smooth, even and uniformly compacted course true to cross
section and grade. A minimum slope of the finished base course shall
be 1/2 inch per foot or as may be required on curves or on superelevations.
(c)
Any portion of the base course material which is not accessible
to means of proper compaction with rolling equipment shall be compacted
thoroughly by methods satisfactory to the Community Services Department.
All yielding or unstable material shall be excavated as directed and
brought up to grade with satisfactory material.
(d)
At all times during construction, the subgrade and all ditches
shall be constructed and maintained so that the roadbed will be effectively
drained to prevent erosion.
(e)
The top four inches of the base course shall not contain stones
over three inches in diameter. The gravel pit shall be acceptable
to the City.
(f)
In areas with excessive clay, water or loam base, the depth
of the base course shall be more than the minimum depth. The base
course depth and required base drainage shall then be properly designed
by the subdivision engineer and approved by the City Engineer (e.g.,
by increasing base depth as needed or road underdrains, or both).
(g)
Design depth shall be based on current engineering practices,
using percolation results obtained during the wet season, soil-bearing
capacity and type.
(h)
Samples of all gravel materials and gradation analysis to be
used in project shall be submitted to the City Engineer's office upon
request.
(2) Street paving.
(a)
Street paving shall be accomplished by placing a minimum of
four inches in two courses of hot asphalt concrete for streets that
are to become public streets. The minimum thickness of each course
shall be as shown on the standard cross section which shall be placed
with a self-propelled mechanical spreader and compacted with a minimum
ten-ton tandem roller. Paving shall be allowed between April 15 and
November 15 only and shall not be placed unless the atmospheric temperature
in the shade is above 40° F. and the mixture delivered to the
spreader has a temperature above 250° F. Pavement shall not be
placed on wet or frozen roadbeds. Unless otherwise specified, paving
regulations shall be the same as those specified in the State of New
Hampshire Department of Transportation Standard Specifications for
Road and Bridge Construction, adopted and approved, latest edition.
In special instances, when it has been determined that there is an
emergency situation, the above requirements may be waived by the Community
Services Director. The Planning Board shall be notified of any waivers
by the Director of Planning and Community Development.
(b)
The hot-asphalt concrete shall consist of the following materials:
the aggregate shall be as indicated in New Hampshire Department of
Transportation specifications; bituminous material shall be an asphalt
cement AC 85-20100, unless otherwise designated on the plans ordered;
and the percentage of bituminous material shall be determined at the
plant site to ensure proper control. This is in no way to relieve
the contractor from designing a road pavement for a higher classification
of traffic which would require a heavy pavement for strength or a
different design mix as approved by the Community Services Department.
(c)
The subdivider shall be required to improve arterial and collector
streets only to the width required by the current and immediate needs
of his subdivision, consistent with the standards and specifications
herein contained.
(d)
Alleys, where permitted or required, shall have not less than
a four-inch bituminous concrete surface and a sixteen-inch base course
as required for streets.
E. Where a subdivision will create a public roadway, a sign shall be
erected on the site alerting those traveling the roadway that they
are on a roadway that is not accepted or maintained by the City of
Dover and they travel at their own risk. Said signage shall be located
and approved by the City Engineer or Director of Planning and Community
Development prior to land disturbance.
[Amended 8-26-2008; 1-24-2012]
All areas of a subdivision shall be graded to prevent ponding of water or eroding of property. In addition to the installation of curbs or gutters along the streets as required by §
157-46, storm sewers or other drainage appurtenances shall be constructed throughout the entire subdivision to carry off water from all inlets and catch basins and be connected to an adequate outfall. The stormwater drainage system shall be separate and independent of the sanitary sewer system and shall be in accordance with drainage laws of the State of New Hampshire. Included in the overall design shall be any work necessary in order to provide adequate and satisfactory drainage along the side of any existing street which is adjacent to the subdivision. The plans and specifications for the disposing of stormwater and the construction thereof shall be approved by the City Engineer. Manholes will be required upon request, to be located between catch basins.
A. Design.
[Amended 5-24-2016]
(1) Proper sizing of culverts, pipes, etc., shall be by acceptable established
engineering practice.
(2) Design storm frequency requirements shall be as follows:
(a)
Major streams, rivers, bridges and culverts: 100-year storm
or flood of record.
(b)
Minor brook culverts: fifty-year storm.
(c)
Storm sewers: ten-year storm.
(3) A sample set of the calculations used in sizing the various pipes
and a list of the variables used must be submitted to the City Engineer's
office. Failure to include this information could result in a delay
of the review process.
B. Standards of construction.
(1) All improvements shall meet the specifications of the American Association
of State Highway and Transportation Officials (AASHTO) in regards
to material and strength requirements.
(2) Catch basins or drop inlets shall be equal to New Hampshire Standard
Type A with three-foot sumps or four-foot sumps with hoods, if required
by the City Engineer.
(3) Minimum size pipe shall be 12 inches in diameter for storm drains.
Minimum size culvert shall be 15 inches in diameter.
(4) All pipes shall be one of the following:
[Amended 5-24-2016]
Typical Use
|
RCP
|
HDPE
|
PVC
|
---|
Culverts
|
X
|
X
|
—
|
Storm drains
|
X
|
X
|
X
|
Drive culverts
|
X
|
X
|
—
|
Underdrain (6-inch)
|
—
|
X
|
X
|
NOTES:
|
X
|
=
|
Acceptable
|
RCP
|
=
|
Reinforced concrete pipe (Class III minimum)
|
PVC
|
=
|
Polyvinyl SDR 35 pipe
|
HDPE
|
=
|
High-density polyethylene
|
(5) There shall be a three-foot minimum cover over all pipes.
(6) Culvert headwalls/endwalls, when required, shall be either concrete
or mortar rubble masonry.
(7) Erosion protection of ditches or pipe outlets shall be provided where
soil and/or velocity conditions warrant protection by paving or use
of stone.
(8) No stormwater pipe, catch basin, drainage inlet or other pipes (floor
drains) used to drain surface water shall be connected to any sanitary
sewer system.
[Amended 9-8-1987; 1-24-2012]
A. All subdivisions in the City of Dover shall provide municipal water
service when available or required by the Planning Board. Installation
of all water mains is subject to the approval of the Community Services
Department.
[Amended 1-14-2020]
B. When City water is supplied, each lot shall have a separate connection
brought to the lot line, equipped with an outside stop and capped
until ready for use. All house service lines shall be connected to
the main by the use of tapped couplings. The developer shall provide
ties for the end of the service and the outside stop to the City Engineer's
office for each lot in the development.
C. When City water is available and/or required, the system shall be
designed by a qualified registered engineer. Each system shall be
designed to handle the expected flows, domestic and fire, for present
and future development within the subdivision.
D. In general, the design of City water mains shall follow the guidelines
prescribed by the American Waterworks Association (AWWA). In addition,
thrust blocks shall be supplied as necessary and gate valves shall
be provided on all sides of junctions with other mains. All waterlines
shall be installed with a minimum of five feet of cover. The minimum
size of a water main shall be eight inches in diameter. The water
main shall be sized to provide adequate fire flow to the proposed
development and any future development. The design size must be approved
by the City Engineer.
E. Materials selected for water construction shall be American-made,
meet American Waterworks Association standards and shall meet the
following minimum requirements:
(1) Pipe and fittings. All pipe shall be cement-lined ductile iron pipe,
Class 52. All fittings shall be ductile iron. All fittings and pipe
shall be American Waterworks Association standard Class 140, coal-tar
dipped or greater. All valve boxes shall be ductile iron and of the
sliding type, tar-coated, both inside and out. All gate valves shall
be Mueller or Clow and must open counterclockwise.
(2) Hydrants. All hydrants shall be Eddy manufacture and subject to the
following additional details. All hydrants shall be of iron body.
All hydrants shall be the improved type with breakable flanges, painted
red body with silver reflective domes and nozzles. All hydrants shall
open counterclockwise, with the direction of opening cast on the head
of the hydrant. All hydrants shall have a valve opening of 5 1/4
inches, hose nozzles conforming to the national standard of nozzles
and 2 1/2 inches and steamer nozzle 4 1/4 inches. Hydrants
shall be long enough to accommodate a minimum bury of 5 1/2 feet
and equipped with six-inch pipe connections. All hydrants shall be
plugged.
F. Construction standards shall be clearly emphasized in the specifications.
Attention should be directed to bedding and backfill requirements.
Various gates and other fittings shall be installed in conformance
with manufacturer's specifications. Hydrants shall be installed not
less than one foot nor more than three feet from the curb and so installed
that the center of the hydrant steamer nozzle shall be at least 18
inches above the finish grade. All hydrant gate valves shall be installed
with anchoring tees to the water main with the top of the box flush
with finish grade.
G. The Director of Community Services shall be notified at least 48 hours prior to any construction involving water mains. All new pipes shall be inspected as provided by §
157-37. Tests to be performed shall include but not be limited to water sampling and testing for contamination.
[Amended 1-14-2020]
[Amended 1-24-2012; 7-27-2021]
All regulatory signs shall be installed in conformance with
the Manual on Uniform Traffic Control Devices. A permanent street
marker shall be placed at each intersection designating the names
of the streets entering said intersection and shall comply with the
specifications as provided by the City. All street signs shall be
of the approved size, color and type set forth by the Community Services
Department and shall be purchased at a nominal rate from the Department
or other suitable source of supply. The signs shall be installed at
the expense of the developer and done to the satisfaction of the Community
Services Department. If a roadway is to remain private, a private
sign marker shall be added to the street sign.
[Amended 1-24-2012; 12-18-2012]
For subdivisions that include the construction of a new road,
all utility lines for telephone and electric service shall be placed
underground in the right-of-way or in rear lot easements. Where telephone
and electric service lines are placed underground entirely throughout
a subdivided area, said conduits or cables shall be placed within
easements or dedicated public ways in a manner which will not conflict
with other underground services. They shall be a minimum of five feet
from any other utility. Wherever possible, underground services will
be placed under grassed areas rather than paved areas. Further, all
transformer boxes shall be located so as not to be unsightly or hazardous
to the public. Additionally, all streetlighting fixtures and poles
shall be approved by the Community Services Director or designee.
The most energy-efficient streetlighting shall be installed.
[Amended 8-11-1992; 11-28-1995; 12-18-2012]
A sidewalk is required on at least one side of a street in the
urban core and may be required by the Planning Board on both sides
of the street where it is deemed appropriate. Sidewalks shall be of
bituminous concrete or portland cement concrete. Bituminous concrete
shall not be less than 2 1/2 inches in thickness and placed over
a six-inch gravel base. Portland cement concrete sidewalks shall not
be less than four inches in thickness, reinforced by eight-by-eight,
six-by-six wire mesh and placed on a suitable base not less than 12
inches thick. Portland cement concrete sidewalks that cross driveways
shall be not less than six inches thick and meet all the standards
listed above. All sidewalks shall be five feet in width and constructed
adjacent to the property line within the street right-of-way. Sidewalks
shall be designed to be free from obstruction; all streetlights, street
trees, mailboxes, newspaper bins, trash receptacles, or any other
type of obstruction shall be placed in the grass area between the
sidewalk and the curb.
[Amended 8-11-1992; 11-28-1995]
A. All new and improved streets within the urban core shall be provided
with granite curbs. When the curb forms one edge of a sidewalk, the
granite curbing shall be vertical and five inches by 17 inches. Curbs
used to define driveway entrances shall be tapered as per standard
road cross section graphic.
B. Granite slope edge curb shall be installed as specified in Section
609 of the State of New Hampshire Standard Specifications for Road
and Bridge Construction, minimum cross section of stone to be four
inches by 12 inches.
Changes in the terms and specifications contained in Planning
Board approval of the improvement aspects of a subdivision application
may be required in the event subsequent excavations reveal subsurface
conditions which require special attention, e.g., underground water
requiring side drains, etc. All such changes must be approved by the
City Engineer, Director of Planning and Community Development and
the Community Services Director.
[Amended 1-14-2003; 8-26-2008]
A. The developer shall be responsible for submitting an as-built drawing
of the project to the City Engineer's office. The drawings shall include
all items as required in the final plan with as-built locations, dimensions
and sizes. Also included on the as-built drawings shall be water and
sewer locations, depths and ties. The as-built drawings shall be submitted
in Mylar and digital formats and shall be tied into the City's GIS
coordinate system.
B. If a street is to become a public roadway, prior to the City Engineer
processing the request and advising the City Council on whether to
accept street or not, the developer shall be responsible for submitting
a recordable deed and any associated fees to the City Engineer's office.
Once the City Council has accepted the street, the developer shall
be notified, and the City Engineer shall record the deed with the
Strafford County Registry of Deeds within 10 days of acceptance. Upon
registration, a signed, original copy of the deed shall be filed with
the City Clerk's office and a copy submitted to the developer.