[Amended 10-12-1999 by Ord. No. 1345; 6-26-2012 by Ord. No. 2268; 3-28-2017 by Ord. No. 2489]
A. Construction plans shall be prepared by
a registered Delaware professional engineer or a licensed Delaware
land surveyor.
B. Streets dedicated to public use shall be
designed and constructed in accordance with standards established
by the Delaware Department of Transportation, Division of Highways.
C. All entrances to the subdivision from a
public street shall be designed and constructed in accordance with
standards established by the Delaware Department of Transportation.
A letter of no objection or other appropriate entrance approval from
the Delaware Department of Transportation shall be required prior
to final approval of the plan.
D. Private streets to be initially maintained by the developer and ultimately owners of lots within the development may be designed and constructed in accordance with Subsection
B or must comply with the following standards.
E. Road geometry. All roads regulated by Sussex
County shall meet fire access requirements as required pursuant to
the Delaware State Fire Prevention Regulations (DSFPR).
(1) Road width.
(a)
The minimum clear/unobstructed road
width when using curb and gutter shall be 24 feet measured in the
case of a vertical curb from face of curb to face of curb, and in
the case of a rolled curb from flowline to flowline. The curb and
gutter shall meet the DelDOT Standard Construction Details, latest
edition, or stone set in place.
[Amended 2-5-2019 by Ord. No. 2629]
(b)
The minimum clear/unobstructed road
width when using open drainage shall be 24 feet.
(c)
The minimum clear/unobstructed road
width for one-way traffic shall be 14 feet.
(d)
See Subsection
E(7) in this section for additional information regarding on-street parking.
(2) Center-line radii.
(a)
The minimum center-line radii for
all roads posted at 17 miles per hour or less shall be 50 feet.
(b)
The center-line for roads posted
higher than 17 miles per hour shall be increased using the AASHTO
(American Association of State Highway and Transportation Officials)
Green Book for normal crown roads.
(3) Minimum and maximum longitudinal slope.
(a)
The minimum slope for a curbed street
is 0.30%.
[Amended 2-5-2019 by Ord. No. 2629]
(b)
The minimum slope for an open ditch
street is 0.50%.
[Amended 2-5-2019 by Ord. No. 2629]
(c)
The minimum slope across a flowline
is 0.50% unless a concrete valley gutter is used.
(d)
The maximum longitudinal slope for
all roads shall be 10%.
(4) Culs-de-sac.
(a)
No island: The minimum radius for
culs-de-sac without an internal island is 38 feet.
(b)
Island: The paved area of a cul-de-sac
with an internal grass island shall be 14 feet wide for one-way traffic
and 20 feet for two-way traffic. The outer and inner radii shall be
able to accommodate a ladder truck and subject to approval by the
State Fire Marshal's Office.
(c)
Culs-de-sac are required for dead-end
streets: (i) greater than 300 feet in length as measured from the
nearest turnaround area; or (ii) that serve more than four dwellings.
[Amended 2-5-2019 by Ord. No. 2629]
(5) Alternative turnarounds. The following
alternative turnarounds are permitted:
(a)
Those listed in the DSFPR.
(b)
A looped road that meets DSFPR.
(c)
Alternative accesses not listed above
that meets DSFPR.
(d)
The maximum length of a dead-end
street (as measured from the nearest approved turn-around area) shall
neither exceed 300 feet without an additional alternative turnaround
nor serve more than four dwellings.
[Amended 2-5-2019 by Ord. No. 2629]
(6) Cross slope.
(a)
The road cross slope can be a normal
crown, superelevated or reverse crown.
(b)
The maximum cross slope shall be
4%.
(c)
The minimum cross slope shall be
2%.
(7) On-street parking.
(a)
On-street parking shall be prohibited
within the following locations:
[1]
Fifteen feet of both sides of a fire
hydrant and marked in accordance with DSFPR.
[2]
Twenty feet of a traffic control
device (i.e., stop sign/signal).
[3]
Ten feet of the point of tangent/point
of curvature of an intersection.
(b)
These on-street parking requirements shall not affect nor be calculated as part of the parking requirements of Chapter
115, §
115-162A and
B.
(8) Right-of-way and/or access easements. Rights-of-way
shall be used in major subdivisions. Access easements shall be used
in developments where all of the underlying land of the development
will be held in common ownership. The right-of-way or access easements
for non-state-maintained roads shall be:
[Amended 2-5-2019 by Ord. No. 2629]
(a)
Placed three feet behind the back
of curb.
(b)
Placed one foot behind the ten-year
stormwater surface of roadside swales.
(9) Sidewalks. Sidewalks shall satisfy the
following requirements:
[Amended 2-5-2019 by Ord. No. 2629]
(a)
They shall be placed within the right-of-way
or deeded easement in favor of the owner of the common elements.
(b)
A sidewalk can be adjacent to the
travel lane using additional pavement that can be added but must be
differentiated from the travel lane using demarcation every 300 feet.
(c)
If the sidewalk is to be located
between the parking space(s) and the roadway, the parking space shall
extend a minimum of 18 feet beyond the edge of the sidewalk.
(d)
For projects with open drainage (with
or without grass strips), the sidewalk must be placed along the edge
of the travel lane.
(e)
Sidewalks must have five feet of
clear width.
(f)
Sidewalks that are not constructed
adjacent to the travel lane using additional pavement must be constructed
using a mix of 4,000 PSI with fiber mesh.
(g)
All sidewalks must have a minimum
cross slope of 1% and a maximum cross slope of 2%.
(h)
All sidewalk expansion joints shall
consist of rubber or other nonbiodegradable material approved by the
Sussex County Engineer or his or her designee.
(i)
All sidewalks adjacent to curbing
shall have expansion joints that are sealed and caulked with materials
approved by the Sussex County Engineer or his or her designee.
(j)
Street crosswalk markings shall be
placed at intersections and mid-block crossings where average daily
traffic counts are equal to or greater than 1,000.
(10)
Utilities. All utilities shall be
placed within an easement and typically located within the following
utility corridor wherever possible:
(a)
Sewer: center line of road or travel
lane.
(b)
Water: under sidewalk (where installed)
or five feet behind edge of pavement or back of curb.
(c)
CATV/telephone: back of sidewalk
or behind top of ditch bank.
(d)
Gas/propane: two feet behind right-of-way.
(e)
Electric: five feet behind right-of-way.
(11)
Roundabouts. Roundabouts shall be
designed to accommodate a ladder truck entering, exiting and traveling
around the roundabout and subject to approval by the Fire Marshal's
Office.
(12)
Eye brows. Eye brows are noncircular
culs-de-sac that have various shapes and sizes that may provide design
flexibility. Eye brows shall be designed to accommodate a ladder truck
entering and exiting the eye brow and subject to approval by the Fire
Marshal's Office.
(13)
Internal intersections. The minimum
radius at edge of pavement for an internal intersection shall be 25
feet.
(14)
Sight distance. No vegetation or
ground/monument signs may be placed within 50 feet of the point of
tangent/point of curvature of an intersection with a height greater
than three feet, unless shown otherwise with a site triangle.
(15)
Curb islands. All landscaped curbed
islands shall have an underdrain or liner along back of curb to prevent
oversaturation from undermining the curb.
(16)
Alleys.
(a)
The maximum clear/unobstructed pavement
width shall be 16 feet.
(b)
The minimum clear/unobstructed pavement
width shall be 12 feet.
(c)
The longitudinal cross slopes shall comply with Subsection
E(3) and
(6) of this section.
F. Storm drainage.
(1) Design storm. Storm drainage systems within
roadways regulated by Sussex County shall be designed using the Rational
Method to convey the ten-year storm event. The Sussex County Rainfall
Intensity Duration Frequency Curves and Rainfall Intensity Table as
defined in the DelDOT Roadway Design Manual shall be used for design
purposes.
(2) Additional requirements. For drainage along
roadways with greater than 3,000 ADT that serve communities with a
single access point, the Sussex County Engineer or his or her designee
may require additional analysis to demonstrate that the road remains
passable during the twenty-five-year storm event. For purposes of
this requirement, "passable" shall mean that the roadway may have
stationary water of up to six inches higher than the crown of the
road.
(3) Open drainage. Open drainage systems are
allowed for subdivisions with a minimum lot width of 100 feet, or
a width less than 100 feet if utilizing shared driveways with an adjacent
lot, and shall consist of concrete or grass open swales designed in
accordance with the following design criteria:
(a)
Minimum slope:
[1]
The minimum slope of a concrete swale
shall be 0.30%.
[2]
The minimum slope of a grass swale
shall be 0.50%.
(b)
Bottom width:
[1]
Concrete swale: two feet wide with one inch depth valley gutter in the middle. Porous concrete will be subject to the requirements of Subsection
G.
[2]
Grass lined swale: minimum width
of two feet for trapezoidal channel or V-ditch section.
(c)
Side slopes:
[1]
Front slope: four-foot horizontal
minimum: one-foot vertical.
[2]
Back slope: three-foot horizontal
minimum: one-foot vertical with appropriate matting per approved erosion
and sedimentation control (ESC) plans.
[3]
Driveway culvert embankments: three-foot
horizontal minimum: one-foot vertical with appropriate matting per
approved ESC plans.
(d)
Swale depth:
[1]
Minimum of one foot except at furthest
upstream end, where a six-inch depth is required.
[2]
Maximum of 2.5 feet contiguous to
single-family lots, except where approved otherwise by the Sussex
County Engineer or his or her designee.
(e)
Freeboard: The design stormwater
surface elevation for open swales shall not exceed the edge of pavement
or travel lane.
(4) Closed drainage. Closed drainage systems
shall consist of pipe, inlet and manhole network systems.
(a)
Minimum size: Minimum pipe size is
a diameter of 15 inches or equivalent.
(b)
Pipe velocity: The minimum full flow
pipe velocity shall be two feet per second.
(c)
Freeboard: The hydraulic grade line
cannot exceed the rim elevation during the design storm event. The
design storm surface elevation for the downstream stormwater management
facility or receiving water shall be used as the tailwater for the
design of the closed drainage system, or the water surface elevation
at time of peak inflow. Where there is no downstream tailwater impact,
the starting downstream hydraulic grade line elevation shall be the
crown of the discharge pipe. For tidal discharges, the minimum tailwater
shall be mean high water elevation. The tailwater elevation should
be noted on the submitted computations.
(d)
Pipe material: All pipe shall be
reinforced concrete pipe (RCP) or high-density polyethylene pipe (HDPE),
(AASHTO M294 Type S or AASHTO M252 Type S). Flexible pipe (HDPE) shall
have a minimum cover of one foot, as measured from top of pipe to
bottom of bituminous concrete pavement, or to the wearing surface
of concrete pavement. Rigid pipe (Class III/IV RCP) shall have 12
inches of cover to the wearing surface of asphalt pavement or nine
inches of cover to the top of stone in a concrete pavement section.
Cover requests less than those specified above for RCP must be accompanied
with load calculations based on methodology in the American Concrete
Pipe Association's Concrete Pipe Design Manual. Alternate pipe materials
for pipe diameters greater than 36 inches shall be allowed by the
Sussex County Engineer or his or her designee on a case-by-case basis.
(5) Cross road culverts.
(a)
Minimum size: The minimum size is
15 inches in diameter or equivalent.
(b)
Pipe slope: The minimum full pipe
flow velocity shall be two feet per second.
(c)
Personnel safety grates: All culverts
shall have a personnel safety grate as required by the Department
of Natural Resources and Environmental Control.
(6) Driveway culverts:
(a)
Minimum size: The minimum culvert
size is 12 inches in diameter.
(b)
Pipe slope: The minimum full pipe
flow velocity shall be two feet per second.
(c)
Pipe material: Pipe shall be RCP
or HDPE (AASHTO M294 Type S). HDPE shall be allowed with minimum six
inches cover of stone over the pipe during homebuilding operations
and Type B Graded Aggregate Base Course (GABC) backfill.
(d)
Analysis: An analysis of driveway culverts is required on the downstream portion of a lot to ensure that they are sufficiently sized to convey water without impeding drainage in the roadside ditch. Culvert size for each individual lot shall be shown in the construction plans required by §
99-30.
G. Stormwater management in street or road
rights-of-way. Stormwater management design within all street or road
rights-of-way shall be in accordance with the Delaware's Sediment
and Stormwater Regulations and accompanying technical documents, or
as otherwise approved by the Sussex Conservation District, or other
applicable regulation. The stormwater management plan shall be approved
by the Sussex Conservation District.
(1) Several best management practices are suitable
for use within the right-of-way, as listed below, and shall be designed
in accordance with the Department of Natural Resources and Environmental
Control's Technical Document, Chapter 3.06.02, Post Construction Stormwater
BMP Standards and Specifications, as that document may be amended
or supplemented.
(a)
Sheet flow to filter strip.
(c)
Vegetated channel/bioswale.
(d)
Infiltration practices.
[2]
Perforated pipe with infiltration.
(e)
Permeable pavement systems, as follows,
may be used in the right-of-way at the discretion of the Sussex County
Engineer or his or her designee.
(g)
Detention practices (underground).
Detention systems under the pavement section may be approved on a
case-by-case basis by the Sussex County Engineer or his or her designee.
(h)
Proprietary practices as may be approved
by the Sussex County Engineer or his or her designee.
(i)
Other practices that become approved
by the Department of Natural Resources and Environmental Control or
the Sussex Conservation District, as allowed by the Sussex County
Engineer or his or her designee.
(2) Stormwater management practices outside
of the right-of-way that are designed to treat roadway drainage must
be located in a deeded open space area and contained within an easement.
H. Road pavement design.
(1) Average daily trips. For the purposes of
this chapter, the following average daily trips (ADTs) per unit shall
be used:
(a)
Single-family dwelling: 10 ADTs per
unit.
(b)
Townhouse: seven ADTs per unit.
(c)
Multifamily dwelling (not townhouse):
six ADTs per unit.
(d)
Manufactured home: five ADTs per
unit.
(e)
Retirement community: four ADTs per
unit.
(2) Subbase course for standard pavement must
include one of the following:
(a)
Graded aggregate base course: eight-inch
maximum lift.
(b)
Crushed concrete: eight-inch maximum
lift.
(c)
Millings: eight-inch maximum lift.
(3) Bituminous concrete for standard pavement
must include one of the following:
(a)
Type bituminous concrete base course:
four-inch maximum lift.
(b)
Type B: four-inch maximum lift.
(c)
Type C: two-inch maximum lift.
(4) Porous bituminous concrete.
(a)
May be permitted in consultation
with the Sussex County Engineer or his or her designee.
(b)
Must include a maintenance management
plan.
(5) Porous Portland cement concrete.
(a)
May be permitted in consultation
with the Sussex County Engineer or his or her designee.
(b)
Must include a maintenance management
plan.
(6) Pavers.
(a)
May be permitted in consultation
with the Sussex County Engineer or his or her designee.
(b)
Must include a maintenance management
plan.
(7) Structural numbers (SN).
(a)
One to 50 ADT shall require SN > 2.42 based on California Bearing Ratio 10. Base course
sections shall be equivalent to 80% of the SN; provided, however,
that the topcoat shall not be less one-and-twenty-five-hundredths-inch
Type C.
(b)
Fifty-one to 3,000 ADT shall require
SN > 3.06 based on California Bearing Ratio
10. Base course sections shall be equivalent to 80% of the SN; provided,
however, that the topcoat shall not be less one-and-twenty-five-hundredths-inch
Type C.
(c)
Greater than 3,001 ADT: Pavement
section shall be determined by a geotechnical engineer.
I. Unless otherwise provided herein, all materials
used in work governed by this section shall meet or exceed the DelDOT
Standards and Specifications for Road and Bridge Construction, as
amended.
J. The Sussex County Engineer shall have,
in appropriate circumstances and upon a written finding of good cause,
the ability to grant administrative waivers from the requirements
of this section.
[Amended 12-7-2004 by Ord. No. 1734]
A. Where the proposed subdivision includes
lands proposed for use as parks, playgrounds, playfields, public landings
or school sites in the Comprehensive Plan, the subdivider shall indicate
the location of such lands on the subdivision plat and shall reserve
the right of purchase of such lands by the appropriate jurisdiction
for the time period specified herein. If the reserved lands are not
purchased by the appropriate jurisdiction within the specified time
limit, the subdivider shall be free to market such lands for an alternate
purpose as specified on the approved subdivision plat.
B. Park, playground and playfield areas may
be required to be reserved for a period of two years from the date
of recording the subdivision, and school sites shall be reserved for
four years from such date.
C. Where deemed essential by the Commission
upon consideration of the type of development proposed in the subdivision,
the subdivider may be required to dedicate other areas or sites of
a character, extent or location suitable to meet the needs of such
development. In lieu of dedication, such additional areas may be reserved
for the common use of all property owners in the proposed subdivision
through deed restrictions or agreements approved by the Commission,
which restrictions or agreements may include a right of enforcement
by the County Council.
D. For residential subdivision and other residential
land development, the following table shall serve as a guide for determining
the minimum percentage of the total site which shall be set aside
for park and open space uses:
[Amended 12-16-2008 by Ord. No. 2022]
Gross Density
(dwelling units per acre)
|
Minimum Percentage of Open
Space
|
---|
2 to 5
|
10%
|
6 to 10
|
15%
|
Over 10
|
25% or more
|
E. Community
buildings, recreational facilities (including swimming pools, game
courts, play areas, tot lots, playgrounds, walking paths, bike paths
and multimodal paths) and the associated parking areas shall be constructed
and open to use by the residents of a subdivision on or before the
issuance of the residential building permit representing 60% of the
total residential building permits for the subdivision.
[Added 7-18-2023 by Ord. No. 2938]