[Ord. No. 8-1997, § 15(H), 7-15-1997]
The standards in this division shall apply to the construction
of roads and/or driveways and drainage systems, culverts and other
related features.
[Ord. No. 8-1997, § 15(H)(1), 7-15-1997; Ord. No. 16-2000, 8-15-2000; Ord. No. 20-2004, 1-6-2004; Ord. No. 3-2005, 7-20-2004]
(a) New roads and driveways in the General Development, and Urban Residential,
Stream Development and Manufactured Housing Community districts shall
be setback 25 feet from the normal high water line. There is no setback
requirement from the normal high water line for new roads and driveways
in the Waterfront Development district. New roads and driveways in
the Limited Residential district shall be set back at least 100 feet
from the normal high-water line of Upper Mason Pond and the portion
of the Goose River that flows into this Pond and 75 feet from the
normal high-water line of other water bodies, tributary streams, or
the upland edge of a wetland unless no reasonable alternative exists
as determined by the Planning Board. If no other reasonable alternative
exists, the Planning Board may reduce the road and/or driveway setback
requirement to no less than 50 feet upon clear showing by the applicant
that appropriate techniques will be used to prevent sedimentation
of the water body. Such techniques may include, but are not limited
to, the installation of settling basins, and/or the effective use
of additional ditch relief culverts and turnouts placed so as to avoid
sedimentation of the water body, tributary stream, or wetland.
(b) On slopes of greater than 20%, the road and/or driveway setback shall
be increased by 10 feet for each 5% increase in slope above 20%.
(c) This section shall neither apply to approaches to water crossings
nor to roads or driveways that provide access to permitted structures
and facilities located nearer to the shoreline due to an operational
necessity.
[Ord. No. 8-1997, § 15(H)(2), 7-15-1997]
Existing public roads may be expanded within the legal road
right-of-way, regardless of the setback from a water body.
[Ord. No. 8-1997, § 15(H)(4), 7-15-1997; Ord. No. 20-2004, 1-6-2004]
New roads and driveways are prohibited in a Resource Protection
and Stream Protection Districts except to provide access to permitted
uses within the respective district, or as approved by the planning
board upon a finding that no reasonable alternative route or location
is available outside the respective district, in which case the road
and/or driveway shall be set back as far as practicable from the normal
high-water line of a water body, tributary stream, or upland edge
of a wetland.
[Ord. No. 8-1997, § 15(H)(5), 7-15-1997]
Road banks shall be no steeper than a slope of two horizontal
to one vertical, and shall be graded and stabilized in accordance
with the provisions for erosion and sedimentation control contained
in division 13 of this article.
[Ord. No. 8-1997, § 15(H)(6), 7-15-1997; Ord. No. 20-2004, 1-6-2004]
Road banks shall conform to specifications identified in chapter
98, Technical Standards, and shall be no greater than 10% except for short segments of less than 200 feet.
[Ord. No. 8-1997, § 15(H)(7), 7-15-1997; Ord. No. 3-2005, 7-20-2004]
In order to prevent road surface drainage from directly entering
water bodies, roads shall be designed, constructed, and maintained
to empty onto an unscarified buffer strip at least 50 feet plus two
times the average slope in width between the outflow point of the
ditch or culvert and the normal high-water line of a water body, tributary
stream, or upland edge of a wetland. Road surface drainage which is
directed to an unscarified buffer strip shall be diffused or spread
out to promote infiltration of the runoff and to minimize channelized
flow of the drainage through the buffer strip. This standard shall
not apply to roads and driveways in the Waterfront Development District.
[Ord. No. 8-1997, § 15(H)(8), 7-15-1997]
Ditch relief (cross drainage) culverts, drainage dips and water
turnouts shall be installed in a manner effective in directing drainage
onto unscarified buffer strips before the flow in the road or ditches
gains sufficient volume or head to erode the road or ditch. To accomplish
this, the following shall apply:
(1) Ditch relief culverts, drainage dips and associated water turnouts
shall be spaced along the road at intervals no greater than indicated
in the following table:
|
Road Grade
(percent)
|
Spacing
(feet)
|
---|
|
0—2
|
250
|
|
3—5
|
200—135
|
|
6—10
|
100—80
|
|
11—15
|
80—60
|
|
16—20
|
60—45
|
|
21+
|
40
|
(2) Drainage dips may be used in place of ditch relief culverts only
where the road grade is 10% or less.
(3) On road sections having slopes greater than 10%, ditch relief culverts
shall be placed across the road at approximately a thirty-degree angle
downslope from a line perpendicular to the centerline of the road.
(4) Ditch relief culverts shall be sufficiently sized and properly installed
in order to allow for effective functioning, and their inlet and outlet
ends shall be stabilized with appropriate materials.
[Ord. No. 8-1997, § 15(H)(9), 7-15-1997]
Ditches, culverts, bridges, dips, water turnouts and other stormwater
runoff control installations associated with roads shall be maintained
on a regular basis to ensure effective functioning.