101.1 Intended
use.
The following Design Criteria are primarily intended
for use by the Developer’s Engineer. There may be special circumstances
which would dictate requirements in excess of those outlined; however,
in most cases, these exceptions will be apparent to the Developer’s
Engineer while preparing the Construction Plans and Specifications
for the subdivision.
101.2 Maintenance.
These criteria and related standards shall be maintained, modified
and kept current by the City Engineer and/or Community Development
Coordinator.
101.3 Related
standards.
The latest version of Standard Specifications
for Public Works Construction, North Central Texas of the North Central
Texas Council of Governments, with all amendments thereto, shall govern
and shall constitute the technical specifications and is made a part
thereof, but is not physically bound within this document except as
amended by the City of Overton Construction Standards (more commonly
referred to as Construction Details).
101.4 Compliance
required.
All subdivision, development and new construction
shall comply with all related City Ordinances, including, but not
limited to, the Subdivision Ordinance and Zoning Ordinance.
101.5 Conformance
required.
The City Council and the City or its representatives
shall approve no final plat, shall accept no completed improvements,
shall issue no permits or rights to occupy unless and until such improvements
conform to these standards herein listed and all other applicable
standards as prescribed by the City of Overton.
All improvements, including, but not limited to, streets, alleys,
sidewalks, drainageways, water and sanitary sewer lines, shall be
designed, placed and constructed in accordance with the following
Design Criteria and Construction Standards.
101.6 Flood
Areas.
Any land which in its natural state is subject
to a one-hundred-year flood or which cannot be properly drained shall
not be subdivided, resubdivided or developed until receipt of evidence
that the construction of specific improvements proposed by the Developer
can be expected to yield a usable building site. Thereafter, the Planning
and Zoning Commission may recommend approval of the plat; however,
construction upon such land shall be prohibited until the specific
improvements have been planned and completed.
101.7 Variances.
Where specific topographic or other conditions make variance
from these standards necessary in order to achieve the best overall
design, the Community Development Coordinator upon recommendation
from the City Engineer and Public Works Director may modify these
standards.
101.8 Special
Exceptions.
Where the appropriate use of the neighboring
property will not be substantially injured, the Community Development
Coordinator, after consultation with the City Engineer, may in specific
cases, and subject to appropriate conditions and safeguards, authorize
special exceptions to the Design Criteria items in order to permit
reasonable development and improvement of property where literal enforcement
of these values would result in an unnecessary hardship.
101.9 Design
Standards.
For any detail or design guideline not specifically
covered within the City of Overton’s Design Criteria and Construction
Standards Ordinance, the North Central Texas Council of Governments
(NCTCOG) detail or design guidelines shall be used.
(Ordinance 2018.04.19B adopted 4/19/18)
102.1 Length.
The length of a block shall be considered to be the distance
from property corner to property corner measured along the property
line of the block face (1) of greatest distance, or (2) on which the
greatest number of lots face.
Where no existing subdivision controls, the block length should
not be less than five hundred (500) feet in length nor greater than
one thousand six hundred (1,600) feet in length. However, in cases
where physical barriers, property ownership, or individual usage creates
conditions where it is appropriate that these standards be varied,
the length may be increased or decreased to meet existing conditions,
having due regard for connecting streets, circulation of traffic and
public safety.
102.2 Width.
The width of a block shall be considered to be the distance
from property corner to property corner measured along the property
line of the block face (1) of least dimension, or (2) on which the
fewest number of lots face.
102.3 Shape
criteria.
The length, width and shapes of blocks shall
be determined with due regard to:
1. Provision
of adequate building sites suitable to the special needs of the type
of use contemplated, and
2. Zoning
requirements as to lot sizes and dimensions, and
3. Needs
for convenient access, circulation, control and safety of street traffic,
and
4. Limitations
and opportunities of topography.
102.4 Streets.
Intersecting streets should be provided at such intervals as
to serve traffic adequately and to meet existing streets in a safe
manner as determined by the city.
102.5 Walkway
required.
Where long blocks in the vicinity of a school,
park or shopping center are platted, the city may require a public
walkway near the middle of long blocks or opposite a street that terminates
between the streets at the ends of the block. If required, the concrete
walkway shall not be less than four (4) feet nor more than eight (8)
feet in width, through the block from sidewalk to sidewalk, or curb
to curb, or if no street, to the property line adjacent to the school,
park, or shopping center.
(Ordinance 2018.04.19B adopted 4/19/18)
103.1 Design.
Lot design shall provide adequate width, depth, and shape to
provide open area, to eliminate overcrowding and to be appropriate
for the location of the subdivision for the type of development and
use contemplated and in accordance with the Zoning Ordinance of the
City of Overton.
103.2 Width.
No lot shall have less width at the building line than is required
by the Zoning Ordinance.
103.3 Building
lines.
Building lines shall be shown on all lots in the
subdivision but shall not be less restrictive than the Zoning Ordinance.
103.4 Side
lines.
All side lines of lots shall be at approximately
right angles to straight street lines and radial to curved street
lines, except where a variation to this rule will provide a better
street and lot layout.
103.5 Front
yard.
The shorter dimension across a residential lot,
adjacent to a street, shall designate the front yard orientation of
the lot, unless otherwise specified on the face of the plat.
103.6 Adequate
size.
Depth and width of properties reserved or laid
out for commercial and industrial purposes shall be adequate to provide
for the off-street service and parking facilities required by the
type of use and development contemplated.
103.7 Frontage.
Every lot shall have frontage on, and access to, a public street.
103.8 Double
frontage.
Double frontage and reverse frontage lots should
be avoided except where essential to provide separation of residential
development from traffic arteries or to overcome specific disadvantages
of topography and orientation.
103.9 Access
limits.
Residential lots shall not have direct access
onto thoroughfare streets, and direct access from residential lots
shall be permitted on collector streets only where design conditions
do not permit any other possibility.
103.10 Large lots.
Where the area is divided into larger lots
than for normal urban building sites, and in the opinion of the city,
any or all of the tracts are susceptible of being resubdivided, the
original subdivision shall be such that the alignment of future street
dedications may conform to the general street layout in the surrounding
area so that the larger tracts may be later subdivided in conformance
with the requirements of this Ordinance and the minimum standards
specified by the Zoning Ordinance.
103.11 Markers.
Lot markers shall be iron pins not less than
one-half (1/2) inch in diameter and no less than eighteen (18) inches
long and shall be set flush with the ground at each lot corner.
103.12 Corners.
All lot corners shall be set prior to the acceptance
of the public improvements and shall be marked in a way that is traceable
to the responsible registrant or associated employer.
103.13 Control monuments.
A minimum of two (2) four-inch x
four-inch x eighteen-inch concrete monuments with one-half-inch x
eighteen-inch reinforcing rebar may be required to be placed in easily
accessible locations, such as street intersections or point of curvatures
and may be required to be placed below back of curb for monument protection.
(Ordinance 2018.04.19B adopted 4/19/18)
104.1 Utility
easements.
Utility easements shall be provided on subdivision
plats when the following criteria indicate that an easement is required:
1. Where
not adjacent to a public right-of-way, easements at least fifteen
(15) feet wide for utility construction, service and maintenance shall
be provided where necessary in locations approved by the city, and
2. Easements
at least fifteen (15) feet wide for utility construction, service
and maintenance shall be provided for lots which have frontage along
state highways, and
3. Easements
of at least ten (10) feet in width shall be provided on each side
of all rear lot lines and alongside lot lines, where necessary, for
utilities such as electric, telephone and gas, and
4. Easements
having greater width dimensions may also be required along or across
lots where engineering design or special conditions make it necessary
for the installation of utilities outside public right-of-ways.
The following statement of restrictions shall be placed in the
dedication instrument:
UTILITY EASEMENT RESTRICTION:
|
Any public utility, including the City of Overton, shall have
the right to remove all or part of any building, fences, trees, shrubs,
other growths or improvements which in any way endanger or interfere
with the construction, maintenance, or efficiency of its respective
systems on any of the easements shown on the plat; and any public
utility, including the City of Overton, shall have the right at all
times of ingress and egress to and from and upon said easements for
the purpose of construction, reconstruction, inspection, patrolling,
maintaining and adding to or removing all or part of its respective
systems without the necessity at any time of procuring the permission
of anyone.
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104.2 Fire
lane easement.
Emergency access and fire lane easements
shall be provided in locations required by the Fire Marshal of the
Overton Fire Department. These easements shall have a minimum width
of twenty (20) feet (twenty-four (24) feet when parking is located
on both sides of the easement) and a minimum height clearance of fourteen
(14) feet. Any emergency access and fire lane easement more than one
hundred (100) feet in length shall either connect at each end to a
dedicated public street or be provided with a cul-de-sac having a
minimum diameter of eighty (80) feet with an additional distance of
ten (10) feet on all sides clear of permanent structures. These easements
shall be paved in accordance with these Design Standards and shall
be maintained by means of a Homeowners’ Association, the property
owner granting the easement or other means as approved by the city.
104.3 Public
open space easement (POSE).
A fifteen-foot x fifteen-foot
triangular public “open space” easement is required on
corner lots at the intersection of an alley and a street.
|
Local
|
Collector
|
Thoroughfare
|
---|
Local
|
1
|
1
|
2
|
Collector
|
1
|
2
|
2
|
Thoroughfare
|
2
|
2
|
3
|
A triangular public open space easement (POSE) is required
on corner lots at the intersection of two (2) streets in accordance
with the table above:
3. Type
3 POSE = 45' x 45'
The following full statement of restrictions shall be placed
in the dedication instrument or on the face of the plat:
PUBLIC OPEN SPACE EASEMENT RESTRICTION:
|
No structure, object or plant of any type may obstruct vision
from a height of thirty (30) inches to a height of ten (10) feet above
the top of the curb, including, but not limited to buildings, fences,
walks, signs, trees, shrubs, cars, trucks, etc., in the public open
space easement as shown on the plat.
|
104.4 Drainage
easement.
Drainage easement requirements are as follows:
1. Easements
for storm drainage facilities shall be provided at locations containing
proposed or existing drainageways.
2. Storm
drainage easements of fifteen (15) feet minimum width shall be provided
for existing and proposed enclosed drainage systems. Easements shall
be centered on the systems. Larger easements, where necessary, shall
be provided as directed by the City Engineer.
3. Storm
drainage easements shall be provided for emergency overflow drainageways
of sufficient width to contain within the easement storm water resulting
from a one-hundred-year frequency storm less the amount of storm water
carried in an enclosed system of a capacity required by the City of
Overton.
4. No construction
or filling without the written approval of the City of Overton shall
be allowed within a drainage easement, and then only after detailed
engineering plans and studies show that no flooding will result, that
no obstruction to the natural flow of water will result and subject
to all owners of the property affected by such construction becoming
a party to the request. Where construction is permitted, all finished
floor elevations shall be a minimum of one (1) foot above the one-hundred-year
flood elevation.
The following statement of restriction shall be placed in the
dedication instrument of the subdivision plat:
|
DRAINAGE EASEMENT RESTRICTION:
|
No construction or filling, without the written approval of
the City of Overton, shall be allowed within a drainage easement,
and then only after detailed engineering plans and studies show that
no flooding will result, that no obstruction to the natural flow of
water will result; and subject to all owners of the property affected
by such construction becoming a party to the request. Where construction
is permitted, all finished floor elevations shall be a minimum of
one (1) foot above the one-hundred-year flood elevation.
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104.5 Floodway
Easement.
Floodway easement requirements are as follows:
1. Floodway
easements shall be provided along natural drainageways and lakes or
reservoirs. Floodway easements shall encompass all areas beneath the
water surface elevation of the base flood, plus such additional width
as may be required to provide ingress and egress to allow maintenance
of the banks and for the protection of adjacent property as determined
and required by the City Engineer.
2. Existing
creeks, lakes, reservoirs or drainage channels traversing along or
across portions of this addition will remain as an open channel at
all times and will be maintained by the individual owners of the lot
or lots that are traversed by or adjacent to the drainage courses
along or across said lots.
3. The City
of Overton will not be responsible for the maintenance and operation
of said drainageways or for the control of erosion.
4. Each
property owner shall keep the natural drainage channels traversing
or adjacent to his property clean and free of debris, silt or any
substance which would result in unsanitary conditions, and the city
shall have the right of ingress and egress for the purpose of inspection
and supervision of maintenance work by the property owner to alleviate
any undesirable conditions which may occur.
The natural drainage channels, as is the case of all-natural
drainage channels, are subject to storm water overflow and natural
bank erosion to an extent that cannot be definitely defined. The City
of Overton shall not be liable for damages of any nature resulting
from the occurrence of these natural phenomena, nor resulting from
a failure of any structure(s) within the natural drainage channels.
The natural drainage channel crossing each lot is shown by the floodway
easement line as shown on the plat.
|
The following statement of restrictions shall be placed in the
dedication instrument of the subdivision plat:
|
FLOODWAY EASEMENT RESTRICTION:
|
No construction, without the written approval of the City of
Overton, shall be allowed within a floodway easement, and then only
after detailed engineering plans and studies show that no flooding
will result, that no obstruction to the natural flow of water will
result; and subject to all owners of the property affected by such
construction becoming a party to the request. Where construction is
permitted, all finished floor elevations shall be a minimum of one
(1) foot above the one-hundred-year flood elevation.
|
(Ordinance 2018.04.19B adopted 4/19/18)
No alleys shall be allowed in any new development.
(Ordinance 2018.04.19B adopted 4/19/18)
Sidewalks shall be required in all new subdivisions as follows:
1. Sidewalks
shall be constructed for all lots adjoining dedicated streets, along
major thoroughfares where lots do not adjoin the street, across power
line easements and in other areas where pedestrian walkways are necessary.
2. Sidewalks
shall be constructed in all parking areas to assure safe pedestrian
access from parking spaces to structures.
3. Sidewalks
shall be designed and constructed so as to assure uninterrupted connections
between all pedestrian walkways.
4. Sidewalks
shall be designed and constructed to minimize pedestrian and automobile
conflicts in order to provide the safest pedestrian access possible.
5. Sidewalks
shall be designed and constructed so as to connect with existing pedestrian
walkways and to assure connection with future pedestrian walkways.
6. Sidewalks
shall be constructed either one (1) foot from the property line within
the street right-of-way or within a dedicated sidewalk easement and
shall extend along the street frontage including the side of corner
lots and block ends.
7. Sidewalks
along existing thoroughfares or streets so designated by the Master
Plan shall be no less than four (4) feet in width.
8. Sidewalks
abutting screening walls, parking areas or fences shall be five (5)
feet in width.
9. Sidewalk
construction may be delayed until development of lots, but in locations
not adjacent to lots and across bridges and culverts, the sidewalk
shall be constructed with the other improvements to the subdivision.
10. Routing
to clear poles, trees or other obstacles shall be subject to approval
by city development staff.
11. The
plat or construction plans shall show the location of all proposed
sidewalks and shall state at what stage of the project they will be
constructed.
12. All
sidewalks shall conform to ADA requirements.
13. Barrier-free
ramps should be provided for access to the street. The following specifications
shall apply:
i) Ramp
to be four (4) feet in width.
ii) Ramp to be constructed with minimum three thousand (3,000) psi twenty-eight-day
strength concrete.
iii) Ramp concrete thickness shall be the same as the street (six-inch
normal residential).
iv) No. 3 bars shall be used for reinforcement (twenty-four-inch on centers).
v) Curb
return shall match existing curb height of the street and taper to
the connecting walk with a one-foot radius.
vi) Street shall be blocked out (maximum twelve (12) inches) and dowels
installed.
vii) Saw joints shall be made one and one-half inch minimum depth and
sealed with silicone joint sealant material.
viii) Subgrade shall be prepared to a minimum depth of six (6) inches.
ix) At no time shall the walk running parallel to the street be altered.
x) Surface
of walk may be coarse and ribbed to provide extra traction.
(Ordinance 2018.04.19B adopted 4/19/18)
110.1 Private
streets.
All streets, including streets in Planned Developments
as defined by the Zoning Ordinance, not dedicated to the public shall
be paved in accordance with these Design Standards and shall be maintained
by means of a Homeowners’ Association, the property owner or
other means as approved by the Commission.
Any request to dedicate a private street as a public street
shall be approved only if arrangements are made to bring the street
into conformity with all city standards and regulations in effect
at the time of dedication at the cost of affected property owners.
All private streets that intersect with public streets shall
be constructed with standard drive approaches. In such cases where
an unusual condition exists, the City Engineer may approve standard
intersection approaches if the approval is requested prior to the
preparation of the plans. Private streets will be named and shown
on the plat. Street signs for said private streets shall be erected
and maintained by the Homeowners’ Association or property owner.
110.2 Trench
safety.
In conformance with House Bills 662 and 665 as
passed by the Seventieth Legislature Regular Session of the State
of Texas, all construction projects within the City of Overton or
its extraterritorial jurisdiction as provided by the Municipal Annexation
Act (Article 970a, Vernon’s Texas Civil Statutes) shall contain
provisions for trench safety.
On construction projects in which trench excavation will exceed
a depth of five (5) feet, the uniform set of general conditions must
require that the bid documents and the contract include detailed plans
and specifications for adequate safety systems that meet Occupational
Safety and Health Administration standards and that these plans and
specifications include a pay item for these same safety systems.
110.3 Underground
utilities.
All distribution lines, cables, etc. for utilities
shall be installed below ground within the subdivision. Transmission
lines or major cables to provide utilities such as electric, telephone
and cable television to the area as a whole may be located above ground
on the perimeter of the subdivision being served. The installation
of these utilities shall conform to commonly accepted construction
standards and be subject to review by the City Engineer.
110.4 Off-street
parking.
All parking shall be off-street, meaning that
all vehicle maneuvering is done on the subject parcel and not on the
street or right-of-way. The following minimum dimensions apply for
off-street parking:
Parking Angle
|
Stall Width
|
Stall Length
|
Maneuvering Space
|
---|
90 Degrees
|
9 feet
|
18 feet
|
24 feet
|
60 Degrees
|
9 feet
|
18 feet
|
20 feet
|
45 Degrees
|
9 feet
|
18 feet
|
18 feet
|
(Ordinance 2018.04.19B adopted 4/19/18)
111.1 Off-street
parking.
All parking shall be off-street, meaning that
all vehicle maneuvering is done on the subject parcel and not on the
street or right-of-way.
1. Three
thousand six hundred (3,600) psi reinforced concrete with a minimum
thickness of six (6) inches or eight (8) inches of Type A, Grade 2,
Limestone Flexible Base and two (2) inches of Type “D”
HMAC.
2. Subgrade
thickness and content shall be determined from a geotechnical report
sealed by a licensed professional engineer registered in Texas provided
by the developer.
3. Standard
curb and gutter as shown on P-4 of the Construction Standards shall
be placed around all landscaping areas and the external boundary of
the parking area.
4. All off-street
parking areas shall be striped in accordance with the latest addition
of the Manual on Uniform Traffic Control Devices (MUTCD) published
by the Texas Department of Transportation.
5. The following minimum dimensions apply for off-street parking (See Appendix
A):
Parking Angle
|
Stall Width
|
Stall Length
|
Maneuvering Space
|
---|
90 Degrees
|
9 feet
|
18 feet
|
24 feet
|
60 Degrees
|
9 feet
|
20 feet
|
20 feet
|
45 Degrees
|
9 feet
|
19 feet
|
18 feet
|
(Ordinance 2018.04.19B adopted 4/19/18)
112.1 Driveway
approaches.
All driveway approaches connecting to city
streets shall be composed of concrete and shall meet the construction
requirements as specified in Sheet P-5 of the city’s Construction
Standards. (See Tables as referenced F and G [G and H] in section
201.8 for driveway spacing and width details).
The normal driveway grade within the street right-of-way is
set at one-quarter (1/4) inch per foot rise above the top of curb
at the property line. The minimum elevation of a driveway at the right-of-way
is two (2) inches above the top of curb. Barrier-free sidewalk construction
requires a maximum driveway grade as measured from the gutter of eight
(8) percent.
Where driveway construction or reconstruction must occur off
the street right-of-way, the usual maximum grade is fourteen (14)
percent. The maximum change in grade without vertical curve is twelve
(12) percent for any ten (10) feet in distance. Driveways should be
profiled for a distance of at least twenty-five (25) feet outside
the right-of-way to ensure adequate replacement design.
Due to state laws requiring barrier-free construction of sidewalks,
steps or other abrupt changes in sidewalk grades are prohibited at
driveways.
(Ordinance 2018.04.19B adopted 4/19/18)
201.1 Street
classification definitions.
Streets shall be classified
according to the following:
1. Thoroughfare
(principal, major, minor):
The main function of a thoroughfare
is to carry traffic from one (1) urban area to another. The thoroughfare
system serves the major activity centers of urbanized areas. A thoroughfare
is used for longer urban trips and carries a high portion of the total
traffic with a minimum of mileage.
2. Collector:
Carries traffic from local streets to thoroughfare. Also may
serve local facilities such as schools, churches. Uses served would
include medium and high density residential, limited commercial facilities,
schools, some small offices and as direct access within industrial
parks. Collector streets also carry heavy traffic to major commercial
and industrial facilities from thoroughfare. Uses would include office
parks, industrial parks, and community level commercial facilities.
3. Local:
Carries traffic from residential and commercial areas to collector
streets and interconnects individual sites. Local streets carry light
traffic volumes and trips are of a short duration.
201.2 General
requirements.
The following general requirements apply
to street improvements:
1. Adequate
streets shall be provided by the subdivider. The arrangement, character,
extent, pavement width, right-of-way width, grade and location of
each street shall conform to the Master Plan. Each street shall be
considered in its relation to existing and planned streets, topographical
conditions, significant natural features such as mature trees or watercourses,
public safety and convenience, and its relationship to the proposed
uses of land to be served by such street.
2. Whenever
a tract to be subdivided abuts any part of any street so designated
on the Master Plan, or where a street designated on the Master Plan
crosses any part of the tract to be subdivided, such part of the proposed
public street shall be platted. The right-of-way shall be dedicated,
and the street shall be constructed by the subdivider, generally consistent
with the location as indicated on the Master Plan, and to a width
consistent with the Master Plan and the requirements of the Subdivision
Ordinance.
3. Whenever
a subdivision, development or new construction occurs adjacent to
an existing street, the street shall be curbed and guttered according
to the specifications given herein.
4. All streets
shall be designed to coordinate with existing streets in adjoining
subdivisions. When conditions permit, centerline offsets shall be
at least one hundred thirty-five (135) feet. Greater centerline offsets
may be required by the City Engineer and shall be planned where necessary
for traffic safety.
5. Streets
shall be named to provide continuity with existing streets. Names
of new streets shall not duplicate or cause confusion with the names
of existing streets. All street names are subject to approval by the
Planning and Zoning Commission upon recommendation of the City Staff.
6. Where
adjoining areas are not subdivided, the arrangement of streets in
the subdivision shall make provision for the proper projection of
streets into such un-subdivided area.
7. Streets
should be platted to allow two (2) tiers of lots between streets when
possible.
8. The reservation
in private ownership of strips of land at the end of proposed or existing
streets and intended solely or primarily for the purpose of controlling
access to property not included in the subdivision shall be prohibited.
9. Half
streets shall be prohibited, except divided thoroughfare streets where
essential to the reasonable development of the subdivision in conformity
with the other requirements of these regulations, and where the Commission
finds it will be reasonable to require the dedication of the other
half when the adjoining land is subdivided. The other half of the
street shall be platted within the adjacent tract at the time it is
platted.
10. A median
opening with an offset of less than one hundred twenty-five (125)
feet from the centerline of an intersecting street or alley shall
be prohibited.
11. Eyebrows
or partial cul-de-sacs are not permitted on thoroughfare or collector
streets.
201.3 Cul-de-sac.
The following shall apply to cul-de-sacs:
1. Streets
designated to be dead-ended permanently shall be platted and constructed
with a paved cul-de-sac. Any dead-end street of a temporary nature,
if longer than two hundred (200) feet, shall have a surfaced turning
area eighty (80) feet in diameter for a cul-de-sac. Temporary dead-end
streets shall have provisions for future extension of the street and
utilities and, if the temporary cul-de-sac is utilized, a reversionary
right to the land abutting the turnaround for excess right-of-way
shall be provided.
2. A Street
ending permanently in a cul-de-sac should not be longer than six hundred
(600) feet and shall be provided at the closed end with a turnaround
having an outside roadway diameter of at least eighty (80) feet, and
a street property line diameter of at least one hundred (100) feet.
201.4 Street
class requirements.
The following street class requirements
shall apply:
1. Street
layout shall provide for continuation of collector streets in areas
between thoroughfares.
2. Those
local streets designated by the Planning and Zoning Commission shall
be extended through the tract to the tract boundary to provide future
connection with adjoining unplatted lands. In general, these extensions
should be at such intervals as necessary to facilitate internal vehicular
circulation with adjoining unplatted lands.
3. Where
single-family or duplex uses abut an existing or proposed thoroughfare
or collector street, the plat or dedication instrument will provide:
i) Lots
to side onto the arterial with a non-access restriction on the thoroughfare
or collector side, or
ii) Reverse frontage with screening and containing a non-access restriction
along the rear property line, or
iii) Other treatment as may be necessary or required for adequate protection
of adjoining properties, and as approved by the City Council after
taking into consideration the proposed method of off-street parking
and maneuvering which will prevent the necessity of backing into the
thoroughfare or collector street.
201.5 Street
design general provisions.
The following general provisions
shall apply:
1. All dedicated
streets shall conform to the criteria set forth in the Master Plan.
Additional right-of-way will be required at most intersections and
may be required at high-volume driveways to provide for left and right
turn lanes to maintain traffic volume capacities through the intersections.
Additional utility easements may also be required beyond the right-of-way
in some locations.
2. The dedicated
streets shall conform to the minimal design parameters as detailed
in the “Thoroughfare Planning and Design Guides, North Central
Texas Council of Governments” and “Geometric Design of
Highways and Streets by AASHTO.”
3. Streets
shall be designed in accordance with The Texas Department of Transportation’s
Highway Design Division Operations and Procedures Manual.
4. No street
intersections of a thoroughfare (principal, major or minor) shall
vary from a ninety-degree angle by more than five (5) degrees. Intersections
of a collector or local streets shall not vary from ninety (90) degrees
by more than fifteen (15) degrees.
5. All intersections
shall have:
i) A
tangent section at least fifty (50) feet long that meets the angle
of intersection requirements, and
ii) A centerline curve radius of at least four hundred (400) feet.
201.6 Pavement
types.
The developer shall provide a geotechnical report,
sealed by a licensed professional engineer, containing recommendations
for subgrade thickness and content. The minimum pavement thicknesses
are provided below.
1. For Local
Streets serving primarily residential areas, the developer shall construct
six (6) inches reinforced concrete or four (4) inches of Type “B”
and two (2) inches of Type “D” asphalt on a minimum of
eight (8) inches of stabilized subgrade.
2. For Collector
Streets, the developer shall construct seven (7) inches of reinforced
concrete on eight (8) inches of stabilized subgrade or as approved
by the City Engineer.
3. For Thoroughfare
Streets, the developer shall construct eight (8) inches of reinforced
concrete on ten (10) inches of stabilized subgrade or as approved
by the City Engineer.
201.7 Street
signs.
The following requirements shall apply:
1. Street
signs shall be furnished and installed by the Subdivider for all intersections
within or abutting the subdivision.
2. Street
signs shall be six (6) inches extruded, have white lettering on a
green background, be engineer grade reflectorized, and include the
block numbers along with the street name.
3. Stop
signs shall be twenty-four-inch by twenty-four-inch in size and shall
conform to the standards as set forth in the Texas Manual on Uniform
Traffic Control Devices.
4. All signs
shall be of engineer grade reflective material and be located in accordance
with the Texas Manual on Uniform Traffic Control Devices.
5. The sign
pole shall be buried to a minimum depth of two (2) feet and placed
in twelve (12) inches diameter concrete filled posthole. The pole
shall be tall enough to accommodate all applicable signs. The bottom
of the stop sign shall be located seven (7) feet above the finished
grade of the surrounding ground.
6. The developer
shall submit a list of signs to be placed and a graphical representation
of the signs for review by City Staff prior to installation.
201.8 Street
Design Tables.
The following tables provide design information.
Table A. Street Design Criteria
|
---|
Reference Section 201 - Street Improvements of this Ordinance
|
---|
Street Classification
|
Min. Design Speed
(MPH)
|
Max.% Grade
|
Min.% Grade
|
Area Free from Storm Water, Using a 100-Year Frequency Storm
|
---|
Thoroughfares
|
|
|
|
|
Principal
|
70
|
6
|
0.5
|
One lane in each direction
|
Major
|
70
|
6
|
0.5
|
|
Minor
|
60
|
6
|
0.5
|
|
Collector
|
50
|
8
|
0.5
|
One lane or center 12'
|
Local
|
30
|
10
|
0.5
|
|
Table B. Urban ROW Widths
|
---|
Thoroughfare Planning and Design Guides, North Central Texas
Council of Governments, June 1995
|
---|
Functional Class
|
No. Lanes
|
Median
|
Min.
(feet)
|
Recommended
(feet)
|
Intersection
(feet)
|
---|
Principal
|
6
|
Yes
|
132
|
156
|
200
|
|
4
|
Yes
|
108
|
132
|
150
|
Major
|
6
|
Yes
|
110
|
132
|
142
|
|
4
|
Yes
|
86
|
102
|
112
|
|
5
|
No
|
80
|
95
|
105
|
|
3
|
No
|
58
|
70
|
75
|
Minor
|
4
|
Yes
|
80
|
100
|
110
|
|
4
|
No
|
64
|
80
|
90
|
|
3
|
No
|
56
|
68
|
80
|
|
2
|
No
|
50
|
60
|
72
|
Collector
|
4
|
No
|
64
|
78
|
90
|
|
3
|
No
|
56
|
68
|
66
|
|
2
|
No
|
50
|
60
|
60
|
Table C. Lane Widths
|
---|
Thoroughfare Planning and Design Guides, North Central Texas
Council of Governments, June 1995
|
---|
Location
|
Functional Classification
|
Min.
(feet)
|
Recommended
(feet)
|
---|
Urban
|
Principal
|
12
|
12
|
|
Major
|
12
|
12
|
|
Minor
|
11
|
12
|
|
Collector
|
10
|
12
|
Rural
|
Principal
|
12
|
12
|
|
Major
|
12
|
12
|
|
Minor
|
12
|
12
|
|
Collector
|
12
|
15
|
Table D. Median Widths
|
---|
Thoroughfare Planning and Design Guides, North Central Texas
Council of Governments, June 1995
|
---|
Design Speed
|
Minimum
(feet)
|
Recommended
(feet)
|
---|
55+
|
40
|
54
|
45-54
|
22
|
30
|
40-44
|
18
|
22
|
< 40
|
14
|
18
|
Table E. Median Lane Widths for Two-Way Left Turn Lanes
|
---|
Thoroughfare Planning and Design Guides, North Central Texas
Council of Governments, June 1995
|
---|
Speed Limit
(mph)
|
Usual
(feet)
|
Minimum
(feet)
|
---|
0-30
|
12-14
|
11
|
35-40
|
12-14
|
11
|
45-50
|
14
|
12
|
50+
|
16
|
14
|
Table F. Design Speeds
|
---|
Thoroughfare Planning and Design Guides, North Central Texas
Council of Governments, June 1995
|
---|
Location
|
Functional Classification
|
Recommended Range
(mph)
|
---|
Urban
|
Principal
|
45-70
|
|
Major
|
45-55
|
|
Minor
|
40-50
|
|
Collector
|
35-40
|
Rural
|
Principal
|
50-70
|
|
Major
|
50-70
|
|
Minor
|
40-60
|
|
Collector
|
40-50
|
Table G. Access Management Minimum Spacing
|
---|
Thoroughfare Planning and Design Guides, North Central Texas
Council of Governments, June 1995
|
---|
Functional Classification
|
Driveway Spacing
|
Median Openings
|
---|
|
|
Directional
|
Full
|
---|
Principal
|
440
|
2,640
|
5,280
|
Principal (Svc. Rds.)
|
330
|
N/A
|
N/A
|
Major/Minor
|
220
|
440
|
880
|
Collector
|
100
|
N/A
|
330
|
Local
|
One Per Lot
|
N/A
|
N/A
|
Table H. Driveway Widths
|
---|
Area
|
Minimum
(feet)
|
Maximum
(feet)
|
---|
Residential
|
8
|
24
|
Commercial
|
10 - One Way
|
28
|
Industrial
|
10 - One Way
|
30
|
201.9 Horizontal
curves and super elevation.
The alignment of the streets
and thoroughfares is usually determined by the alignments of the existing
right-of-way or structures which cannot be relocated. Changes in the
direction of a street or thoroughfare are minimized by constructing
a simple curve having a radius which is compatible with the speed
of vehicular traffic. To increase the safety and reduce discomfort
to drivers traversing a curved portion of a street or thoroughfare,
the pavement may be super-elevated. Reference “Geometric Design
of Highways by AASHTO” for design standards.
201.10 When
two (2) longitudinal street grades intersect at a point of vertical
intersection (PVI) and the algebraic difference in the grades is one
(1) percent or greater, a vertical curve is required. Vertical curves
are utilized in roadway design to affect a gradual change between
tangent grades and should result in a design, which is safe, comfortable
in operation, pleasing in appearance and adequate for drainage. The
vertical curve will be formed by a simple parabola and may be a crest
vertical curve or a sag vertical curve. Reference “Geometric
Design of Highways by AASHTO” for design standards.
(Ordinance 2018.04.19B adopted 4/19/18)
202.1 General.
This section pertains to general design requirements for water
distribution system construction in the City of Overton.
1. All water
lines shall be sized and designed in accordance with the City of Overton
Water Distribution System Master Plan or as determined by the City
Engineer. In the absence of specific standards, all water supply,
distribution, pumping, and storage improvements shall be designed
in accordance with the most current standards of the American Water
Works Association, the Standard Specifications for Public Works Construction
of the North Central Texas Council of Governments, and criteria adopted
by the Texas Administrative Code, Chapter 290, “Public Drinking
Water.”
2. Water
lines for multi-family, commercial and industrial fire protection
lines shall be dedicated to the public, unless the system is isolated
from the public system by a detector check.
3. The developer
shall furnish, install, construct, or extend, at his own expense,
water distribution facilities necessary for the proper development
of the subdivision. The water system shall provide individual service
to every lot in the subdivision. All water mains constructed within
a proposed subdivision shall be extended to the perimeter of the proposed
subdivision to allow for future extension of the water system into
adjacent properties. The water system shall be designed and constructed
in accordance with the specifications contained in these Standards.
Where considered necessary by City Staff, the facilities shall be
sized in excess of that dictated by these Standards to provide for
the future growth and expansion of the city’s water distribution
system.
202.2 Water
line sizing.
1. All water
lines shall be a minimum of six-inch diameter. Standard water line
sizes are six-inch, eight-inch, twelve-inch, and sixteen-inch diameter.
Other sizes must be approved by the City Engineer.
2. All water
lines shall be looped except in cul-de-sacs. Dead-end lines shall
not exceed fifty (50) feet on multi-family, commercial, or industrial
sites.
202.3 Water
line location.
1. Water
lines shall be located in the parkway. Along State Highways, water
lines are required to be constructed on both sides of roadway. New
water lines crossing existing streets shall be placed by boring. A
casing shall be required under major and minor collector roadways.
Open cut excavation will not be allowed to cross existing streets,
unless approved by the City Engineer.
2. All public
water lines located on private property shall be centered in an easement.
Water lines shall not be located under paved surfaces where possible.
Easements for water line construction shall meet the following requirements:
i) The
easement width shall be a minimum of fifteen (15) feet.
ii) If the water line is less than twelve (12) feet deep, the outside
diameter of the water line shall be located a minimum distance of
six (6) feet from the edge of the easement, and if other utilities
are located in the same easement, the outside diameter of the water
line shall be located a minimum distance of three (3) feet from the
outside diameter of the other utilities.
iii) If the water line is greater than twelve (12) feet deep, the outside
diameter of the water line shall be located a minimum distance of
nine (9) feet from the edge of the easement, and if other utilities
are located in the same easement, the outside diameter of the water
line shall be located a minimum distance of six (6) feet from the
outside diameter of the other utilities.
3. All piping
with mechanical couplings, push-on, or similar joints subject to internal
pressure shall be designed with blocking, anchors, and restraining
harnesses to preclude separation of joints.
202.4 Water
line materials.
1. All new
water line installation shall be AWWA C-900 Polyvinyl Chloride (PVC)
Pipe, blue in color, unless approved otherwise by City Engineer.
2. All materials
shall be in accordance with section “500 Underground Construction
& Appurtenances” as detailed in the “North Central
Texas Council of Governments Public Works Construction Standards.”
3. Fittings
ductile iron in accordance with AWWA C110 or AWWA and section “500
Underground Construction & Appurtenances” as detailed in
the “North Central Texas Council of Governments Public Works
Construction Standards.”
202.5 Installation.
1. General.
i) All
installations shall conform to the latest North Central Texas Council
of Governments Public Works Construction Standards.
ii) All six-inch and eight-inch water pipes shall be installed with a
minimum of forty-two (42) inches of cover over top of pipe; twelve-inch
water pipes shall be installed with a minimum of forty-eight (48)
inches cover. Pipes sixteen (16) inches and larger shall be installed
with a minimum of sixty (60) inches of cover over top of pipe.
iii) The amount of trench excavation shall not exceed two hundred (200)
feet from the end of the pipe laying operations, and no more than
three hundred (300) feet of total open trench will be allowed. At
the end of each work day, all trench excavation shall be backfilled
to the end of the pipe laying operation. Barricades and lights will
be required around any open trench left overnight.
iv) All connections to existing water mains shall be made under pressure
unless dry connections will not cause any loss of service. Under special
conditions connections that cause an interruption of service may be
performed with approval of the City Engineer.
v) Coated
tracer wire shall be installed in the embedment material above the
PVC pipe with the tracer wire terminating in the in-line gate valve
boxes accessible by City Staff. Blue underground water line tape of
a minimum four-inch width shall be installed above the embedment material.
vi) Density tests shall be taken as directed by the City Engineer.
202.6 Fire
hydrants.
1. Fire
hydrants in commercial and industrial areas shall generally be at
street intersections and so located that there will be a fire hydrant
every three hundred (300) feet. Fire hydrants in a residential area
shall be generally located on street intersections and not over five
hundred (500) feet apart. Fire hydrants in a multi-family complex
shall be generally located on street intersections and not over three
hundred (300) feet apart.
2. Materials.
i) Fire
hydrants shall be Mueller (Super Centurion 200) or approved equal.
ii) All materials shall be in accordance with section “500 Underground
Construction & Appurtenances” as detailed in the “North
Central Texas Council of Governments Public Works Construction Standards.”
iii) The fire hydrant body shall be painted a high gloss alkyd fire hydrant
red.
202.7 Valves.
1. Resilient
seated gate valves shall be used for six-inch through sixteen-inch
water lines. Butterfly valves shall be allowed for sixteen (16) inches
and larger water lines when approved by the City Engineer.
2. Valves
of approved design shall be installed at the intersections of all
water mains so as to provide for proper maintenance and operation
of the system and to provide a means of shutting off the supply to
portions of the system for repairs. Valves shall be spaced such that
only one (1) fire hydrant is out of service at any one (1) time. Three
(3) valves shall be used on a four-way water line intersection and
a minimum of two (2) valves shall be used on a three-way intersection.
3. Materials.
All valves shall conform with the “North Central Texas
Council of Governments Public Works Construction Standards.”
4. Installation.
i) Valves
shall be furnished with extensions, such that the working nut is a
maximum of forty-eight (48) inches below grade.
ii) Adjustable valve boxes shall be furnished and set on each valve in
accordance with these standards. Valves that are deeper than forty-eight
(48) inches, AWWA C900 PVC pipe shall be used for stacks, as long
as the adjustable valve box is used at the top.
iii) After the final clean-up and alignment has been complete, the contractor
shall cast in place a concrete block, twenty-four (24) inches by twenty-four
(24) inches around all valve box tops at the finish grade. See Construction
Standards.
iv) Valves located within a right-of-way shall be indicated on the face
of the curb, or where curbs do not exist, on a conspicuous location
adjacent to the valve location. Markings are to be the stamping of
a four-inch high letter “V” with the point of the “V”
pointing towards the valve location.
v) Valve
markers shall be provided in rural areas.
5. Manufacturers.
i) Resilient
seated gate valves shall be Mueller or approved equal.
ii) Butterfly valves shall be Clow or approved equal.
202.8 Air
Release and Flushing Valves.
1. Adequate
air relief and flushing valves shall be provided for flushing, disinfection,
daily operation requirements and repairs when required by the City
Engineer. Air release valves shall be required on twelve (12) inches
and larger water lines. Water lines shall be designed so that each
section of the water line can be flushed at its lowest and highest
points.
2. All dead-end
lines shall have a fire hydrant installed for flushing purposes. If
installation of a fire hydrant is not possible, a flushing valve is
required.
3. A fire
hydrant shall be required at high points on water lines smaller than
twelve (12) inches for air relief and flushing.
4. Air release
valves and air/vacuum valves shall meet or exceed the latest revision
of AWWA C5.
202.9 Tapping
sleeve.
A tapping sleeve and valve shall be used when
connecting a new water line to an existing line. A resilient seated
gate valve shall be flanged to the tapping sleeve. The tapping sleeve
shall be a Smith-Blair type 664-665 stainless steel tapping sleeve
or approved equal.
202.10 Water service.
1. The
water meter box shall be placed a minimum of six (6) inches behind
the back of curb, and the water service shall be no more than twenty-four
(24) inches deep, covered with a meter box in place at grade. If no
curb is present, the water service shall be located at the property
line, no more than twenty-four (24) inches deep, covered with a meter
box in place at grade. Along roadways without a curb the water service
line shall be constructed at a minimum of eighteen (18) inches below
the ditch flow line. All water services crossing beneath streets must
be encased in four-inch diameter PVC casing.
2. Meter
and service sizes will be determined by the developer prior to requesting
service from the city. The minimum water service size between the
water main and the meter shall be three-fourths (3/4) inches and the
minimum meter size shall be five-eighth (5/8) inches.
3. Water
services on undeveloped lots shall be located at the property line
and shall be a minimum of one (1) inch in diameter.
4. Materials.
i) Service
saddle shall be double strap bronze with brass body or stainless steel
double bolt wide straps with stainless steel body. Minimum size tap
shall be three-fourths-inch diameter.
ii) Service lines shall be three-fourths-inch minimum diameter, poly
or type K copper.
iii) Corporation and Curb Stops.
a) Corporation stop shall be two-inch ball type with compression outlet
fitting, designed for a minimum working pressure of two hundred (200)
psi.
b) Curb stop shall be set with compression inlet fitting and lock ring.
iv) Meter box for meters two (2) inches and smaller.
Meter
boxes shall be provided as shown in the Construction Standards.
5. Installation.
i) General.
a) All water service shall be installed in accordance with these standards.
b) Each individual service location shall be saw cut into the face of
the curb with a four-inch high blue “W” painted by the
Contractor. If no curb exists, a similar mark should be placed in
the pavement near the edge of the roadway.
ii) Residential Meters.
All residential meters shall be
the current manufacturer’s brand as set by the City and shall
be purchased through the City.
iii) Commercial Meters (two (2) inches and larger).
The developer
shall purchase from the manufacturer a master compound meter approved
by the City Engineer. The meter shall be installed by a utility contractor
or plumber. All meters in this size class are required to have a strainer
prior to the meter.
6. Acceptable
Manufacturers for Corporation Stops, Curb Stops, and Service Saddles
are Ford, Mueller and Smith-Blair.
202.11 Flushing valves.
1. Materials
i) Corporation
stop shall be two-inch ball type with compression outlet fitting,
designed for a minimum working pressure of two hundred (200) psi.
ii) Two-inch curb stop shall be ball type with compression inlet fitting
with fee [tee] head shut-off.
iii) Pipe shall be two (2) inches diameter, Type K copper as specified
in ASTM B88.
202.12 Water line bore.
1. Casings
shall be required under collectors and thoroughfares, highway crossings,
and railroad crossings. Casings may also be required were deemed necessary
by the City Engineer. The construction bore pit shall be located at
a minimum distance of four (4) feet behind the back of curb or edge
of pavement where no curb is present.
2. Materials.
i) Steel Casing Pipe.
Steel casing pipe shall be new (or
used if approved by the City Engineer), a minimum of 1/4" thickness
and suitable for the purpose intended and shall have a minimum yield
strength of thirty-five thousand (35,000) psi.
ii) All required materials and installation shall be in accordance with
the “North Central Texas Council of Governments Public Works
Standards - Section 503,” “Texas Department of Transportation
Standard Specifications for Construction and Maintenance of Highways,
Streets, and Bridges,” and governing railroad entity when applicable.
(Ordinance 2018.04.19B adopted 4/19/18)
203.1 General.
This section pertains to general design requirements for wastewater
collection system construction in the City of Overton. All sewer lines
shall be sized and designed in accordance with the Master Plan or
as determined by the City Engineer. In the absence of specific standards,
all collection, treatment, and disposal systems shall be designed
in accordance with the most current criteria adopted by the Texas
Administrative Code (TAC), Chapter 217, Design Criteria for Sewerage
Systems.
1. All sewers
shall be designed with consideration for serving the full drainage
area subject to collection by the sewer in question; the drainage
area may be modified with the concurrence of the City Engineer because
of the projected rate of development or the financial feasibility
of the proposed extension.
2. Sewers
should be designed with straight alignment whenever possible. When
horizontal curvatures must be used, the maximum joint deflection should
be in accordance with the pipe manufacturer’s recommendations.
3. The developer
shall furnish, install, construct, or extend, at his own expense,
wastewater collection facilities necessary for the proper development
of the subdivision. The wastewater collection system shall provide
individual service to every lot in the subdivision. All sewer mains
constructed within a proposed subdivision shall be extended to the
perimeter of the proposed subdivision to allow for future extension
of the wastewater collection system into adjacent properties. The
wastewater collection system shall be designed and constructed in
accordance with the specifications contained in these Standards. Where
considered necessary by City Staff, the facilities shall be sized
in excess of that dictated by these Standards to provide for the future
growth and expansion of the city’s wastewater collection system.
4. All sewers
shall be designed with hydraulic slopes sufficient to give mean velocities,
when flowing full or half full, of no less than two (2) feet per second
on Kutter’s or Manning’s formulas using an “n”
value of 0.013. Slopes shall also conform to TAC Chapter 217, Sewage
Collection System.
5. When
a one hundred fifty (150) psi rated sewer, line is required due to
its proximity to a water line, the one hundred fifty (150) psi rated
pipe shall terminate at a manhole on each end. The pipe shall be extended
to the interior wall of the manhole. No external boot connection will
be allowed.
203.2 Sanitary
sewer line sizing.
1. Standard
sewer line sizes are six (6) inches, eight (8) inches, twelve (12)
inches, fifteen (15) inches, and eighteen (18) inches in diameter;
other sizes must be approved by the City Engineer.
2. Sewer
lines shall be a minimum of six (6) inches in diameter.
203.3 Location.
1. Sewer
lines shall be constructed at a minimum depth of four (4) feet. They
shall be located in the parkway and are required to be constructed
on both sides of a state highway. No sewer lines will be allowed to
cross a state highway.
2. Easements
for sewer line construction shall meet the following requirements:
i) The
easement width shall be a minimum of fifteen (15) feet.
ii) If the sewer line is less than twelve (12) feet deep, the outside
diameter of the sewer line shall be located a minimum distance of
six (6) feet from the edge of the easement, and if other utilities
are located in the same easement, the outside diameter of the sewer
line shall be located a minimum distance of three (3) feet from the
outside diameter of the other utilities.
iii) If the sewer line is greater than twelve (12) feet deep, the outside
diameter of the sewer line shall be located a minimum distance of
nine (9) feet from the edge of the easement, and if other utilities
are located in the same easement, the outside diameter of the sewer
line shall be located a minimum distance of six (6) feet from the
outside diameter of the other utilities.
203.4 Materials.
1. All new
sanitary sewer line installation shall be ASTM D-3034 SDR-26 PVC for
four (4) inches through fifteen (15) inches, green in color, unless
approved otherwise by City Engineer. ASTM Designation F-679 shall
be used for pipe sizes greater than fifteen (15) inches.
2. All materials
shall be in accordance with section “500 Underground Construction
& Appurtenances” as detailed in the “North Central
Texas Council of Governments Public Works Construction Standards.”
203.5 Installation.
1. General.
i) All
installations shall conform to the “North Central Texas Council
of Governments Public Works Construction Standards.”
ii) Sewer lines shall not be installed within nine (9) feet horizontally
of any water main or fire hydrant.
iii) Construction shall begin at the downstream end of project and continue
upstream with the bell facing upstream. No upstream piping shall be
installed before downstream piping unless approved by the City Engineer.
2. Excavation
and Backfill.
i) When
PVC pipe is used, green marker tape with the wording “Buried
Sanitary Sewer” shall be installed in the backfill material
no more than twelve (12) inches above the top of the pipe.
ii) The amount of trench excavation shall not exceed two hundred (200)
feet from the end of the pipe laying operations, and no more than
three hundred (300) feet of total open trench will be allowed. At
the end of each workday, all trench excavation shall be backfilled
to the end of the pipe laying operation. Barricades and lights will
be required around any open trench left overnight.
iii) Density tests shall be taken as directed by the City Engineer.
203.6 Inspection.
1. All sanitary
sewer lines shall be inspected as detailed in the “North Central
Texas Council of Governments Public Works Construction Standards -
Section 507.5.”
2. Criteria
for repair.
i) The
Contractor shall make repairs if the inspection reveals any deficiency
in the sewer line. If repairs are required, the segment of line to
be repaired shall be re-tested at the Contractor’s expense.
ii) Repairs shall be made to the satisfaction of the City Engineer and
Public Works Director.
203.7 Manholes.
1. Manholes
shall be located at all intersections of sewer lines and at intermediate
spacing along the line. Generally, the maximum spacing should not
exceed five hundred (500) feet. Manholes should be located at all
changes in grade, direction, and at the ends of all sewer lines that
will be extended.
2. A manhole
is required at the junction of sewer lines with different inside pipe
diameters.
3. A drop
of at least 0.1 feet is required through the manhole when a change
in flow direction occurs.
4. A drop
manhole shall be installed in instances when the flowline into a manhole
should [sic] greater than two (2) feet above the flowline out.
5. Minimum
manhole inside diameter is four (4) feet.
6. Drop-connection
manholes shall have a minimum inside diameter of five (5) feet, with
an interior drop connection if line size is greater than eight (8)
inches.
7. Minimum
cast-in-place manhole wall thickness is eight (8) inches. For depths
greater than twelve (12) feet add an extra four (4) inches of thickness
for each additional six (6) feet of depth.
8. Minimum
pre-cast wall thickness is five (5) inches.
9. A manhole
is required where a sanitary sewer line enters and exits private property.
10. All
manholes shall be constructed of concrete.
11. Installation.
i) Manholes
shall be a minimum diameter of four (4) feet for lines 6"-18" in diameter,
five (5) feet for lines 21"-27" in diameter, and six (6) for 30"-36"
in diameter.
ii) Cast-in-place.
a) Cast-in-place manholes will be constructed in accordance with the
“North Central Texas Council of Governments Public Works Standards,
Section 502.”
b) The manhole shall not be backfilled within twelve (12) hours after
the concrete placement.
c) The face of curb shall be sawed with an “MH” to mark
the location of all manholes. The location of the stamp shall be a
line that intersects the center of the manhole cover and the curb
perpendicular to the centerline of the street. For manholes located
in intersections, the curb shall be stamped at the closest location
to the manhole. If no curb exists, a similar mark should be placed
in the pavement near the edge of the roadway.
iii) Precast Manhole.
a) Precast manholes will be constructed in accordance with the “North
Central Texas Council of Governments Public Works Standards, Section
502.”
b) Manhole base shall have a spread footing and be placed on a minimum
of twelve (12) inches of crushed rock.
203.8 Manhole
Frame and Cover.
1. Cover.
i) All
manhole frames and covers shall conform to the “North Central
Texas Council of Governments Public Works Standards - Section 502.”
ii) All manhole[s] will have a minimum opening of thirty (30) inches
in diameter.
iii) All manhole covers shall have two (2) integrally cast pick bars.
iv) Any manhole covers located below the 100-year water surface elevations,
shall be bolted and gasketed.
2. Extension
Ring.
i) All
precast reinforced concrete extension rings shall conform to ASTM
C-478.
ii) The number of extension ring sections shall be kept to a minimum
(i.e. use 1-12-inch extension ring instead of two- to six-inch extension
rings).
iii) A one inch by three and one-half inch bitumastic gasket shall be
used to seal the extension ring at both joints.
3. Rain
Pan.
i) Rain
pans shall be high density polyethylene plastic.
ii) Acceptable manufacturers include Knutson or approved equal.
203.9 Sewer
Service.
1. No sewer
service line (lateral) shall be less than four (4) inches in nominal
diameter. Commercial sewer laterals shall be six (6) inches minimum
diameter.
2. Sewer
laterals shall be located at the center of the lot and extended to
the property line and be a minimum of ten (10) feet downstream of
the water service.
3. Sewer
service laterals shall have no more than six (6) feet of cover at
the property line unless otherwise approved by City Engineer.
4. A double
cleanout shall be installed at the property line, and a cleanout shall
be located on the service lateral at the time of connection to the
building.
5. All lateral
sewer service lines shall be PVC pipe type SDR-26.
7. All service
laterals shall be installed in accordance with the sanitary sewer
embedment and backfill standards.
203.10 Cleanouts.
All cleanouts are to be constructed of PVC
pipe type SDR-26, and shall be in accordance with the “North
Central Texas Council of Governments Public Works Construction Standards
- Section 502.2.”
203.11 Main Line Cleanouts.
Main line cleanouts shall be located
on dead-end sewer mains at a distance no greater than two hundred
fifty (250) feet from the preceding manhole. If the distance is greater
than two hundred fifty (250) feet, a manhole shall be installed at
the end of the line.
203.12 Aerial sewer.
1. Aerial
sewer crossings shall be located in areas where the sewer line cannot
be constructed with the appropriate minimum cover. All above-ground
sewer installations shall be ductile iron, minimum Class 150, utilizing
restrained joints and shall have a wall thickness required for the
size and span as designed. The pipe shall have an internal polyurethane
coating. The design engineer shall design the aerial crossing in accordance
with these standards and submit a design for approval by the City
Engineer.
2. The
aerial pipe shall be connected to the sanitary sewer pipe by means
of a manhole on each side of the aerial crossing.
3. The
piers for the aerial crossing shall be designed in accordance with
the guidelines of the Ductile Iron Pipe Research Association. Piers
are to be constructed with a minimum of Class A three thousand five
hundred (3,500) psi reinforced concrete. Pier placement and spacing
shall be determined according to soils analysis performed by a geotechnical
engineer. Piers shall be placed at a maximum span distance as indicated
by the design engineer’s calculations. The design engineer shall
submit a pier design for approval by the City Engineer.
203.13 Sewer line boring.
1. Casings
shall be required under collectors and thoroughfares, highway crossings,
and railroad crossings. Casings may also be required were deemed necessary
by the City Engineer. The construction bore pit shall be located at
a minimum distance of four (4) feet behind the back of curb or edge
of pavement where no curb is present.
2. Materials.
i) Steel Casing Pipe.
Steel casing pipe shall be new (or
used if approved by the City Engineer), a minimum of 1/4" thickness
and suitable for the purpose intended and shall have a minimum yield
strength of thirty-five thousand (35,000) psi.
ii) All required materials and installation shall be in accordance with
the “North Central Texas Council of Governments Public Works
Standards - Section 503,” “Texas Department of Transportation
Standard Specifications for Construction and Maintenance of Highways,
Streets, and Bridges,” and governing railroad entity when applicable.
3. All
bores shall be installed at a grade no less than the minimum indicated
by TAC, Chapter 217 for the desired pipe size.
203.14 Lift stations.
1. Lift
stations must be designed in accordance with 30 TAC, Chapter 217.
2. Instrumentation
and control.
i) The
voltage supplied for pump operation shall be three-phase, four hundred
eighty (480) volts. Converting single-phase power to three-phase power
using additional mechanical equipment shall not be allowed.
ii) Wet-well level control shall be achieved through the use of an ultrasonic
level indicating transmitter.
iii) Stations with a total pumping capacity rating less than one thousand
(1,000) gpm shall be equipped with an automatic telephone dialing
system.
iv) Submersible pumps shall be provided with moisture and motor over-temperature
sensors.
3. Site
requirements.
i) A
concrete pad will be required at the front of the control cabinet.
The pad shall provide a three-foot working area away from the face
of the cabinet and extend the width of the enclosure mounting structure.
Pad depth shall be a typical four (4) inches.
ii) A one-inch minimum potable water service is required. The water service
may be set in a standard eighteen-inch galvanized water meter box
with a one-inch brass angle stop.
iii) The site shall be graded to drain away from the station to prevent
storm water inflow or infiltration into the wet-well.
iv) The site shall be located outside of the one-hundred-year floodplain.
v) The
site shall not be located within one hundred (100) feet of an existing
or proposed residence, if possible.
vi) If applicable the lift station site driveway shall include driveway
area for maintenance vehicles to park off public roadway while performing
maintenance. The minimum driveway length shall be fifteen (15) feet.
If the drive extends more than twenty (20) feet from main roads, a
“t” shaped turning is [sic] with applicable turning radius
will be required.
(Ordinance 2018.04.19B adopted 4/19/18)
204.1 General.
Drainage facilities shall be provided and constructed by the
developer in accordance with all city standards and the following
basic requirements.
204.2 Runoff
calculations.
1. The selection
of which method to use for calculating runoff depends upon the size
of the contributing drainage area at the most downstream point of
the project. The “Rational Method” is acceptable for designing
projects in which the drainage area is less than two hundred (200)
acres. A unit hydrograph method is required for projects with larger
drainage areas.
2. No matter
which method is used to calculate runoff, a developer or builder of
property greater than one (1) acre in size, or any property that was
platted as a part of an overall tract which was greater than one (1)
acre in size (including churches and schools), shall develop the property
so that the rate of runoff created by the development as it leaves
the property does not exceed the rate of runoff that would have been
created if the property had developed as a single-family residential
property.
3. Runoff
computations shall be based upon fully developed watershed conditions
in accordance with the land use projections in the latest Master Plan.
The design engineer shall size drainage facilities by disregarding
the detention effects of upstream property and calculating the runoff
as if the off-site property was developed without any detention. If
an approved regional detention/retention facility is in operation,
the design engineer may size downstream drainage facilities based
on consideration of the detention effects of the regional facility.
4. Procedure
for drainage areas less than two hundred (200) acres.
i) Computation
of Storm Water Runoff for drainage areas less than two hundred (200)
acres shall be by the “Rational Method,” which is based
on the principle that the maximum rate of runoff from a given drainage
area for an assumed rainfall intensity occurs when all parts of the
area are contributing to the flow at the point of discharge. The formula
for calculation of runoff by the “Rational Method” is:
Q = CIA
|
Where:
|
Q
|
=
|
the maximum rate of discharge, expressed in cubic feet per second.
|
C
|
=
|
Coefficient of Runoff.
|
I
|
=
|
Intensity of Runoff in inches per hour
|
(Use Appendix B - Intensity-Duration-Frequency Curve (IDF) Curve.)
|
A
|
=
|
Drainage Area in acres.
|
Park areas - No developed land
|
0.30
|
Developed Park sites
|
0.40
|
Single-family Residential
|
0.55
|
Duplex
|
0.60
|
Multiple-Family
|
0.70
|
Schools
|
0.70
|
Churches
|
0.70
|
Neighborhood Commercial
|
0.70
|
Office Commercial
|
0.70
|
Commercial
|
0.85
|
Industrial
|
0.85
|
ii) Time of concentration is the longest time, without interruption of
flow by detention devices, that a drop of water takes to flow from
the farthest point of the drainage area to the point of concentration
(i.e. the point of design). The time of concentration is composed
of the inlet time and the flow time in a conduit or channel to the
point of design.
iii) When designing inlets and laterals, the time of concentration is
equal to the inlet time. The design engineer will compare the above
specified inlet times to the actual calculated inlet time by computing
the flow time overland and along the gutter to the first inlet. Manning’s
equation shall be used to determine flow time to the inlet. The design
engineer may use the actual calculated or specified inlet time.
a) The inlet time shall be ten (10) minutes for property zoned multiple-family,
churches, schools, local business, central business, commercial, or
industrial.
b) An inlet time of fifteen (15) minutes shall be used for property
zoned for parks, cemeteries, agricultural, and single-family residential.
5. Procedures
for Drainage Areas greater than two hundred (200) acres:
i) For
drainage areas in excess of two hundred (200) acres where the use
of the “Rational Method” does not provide reliable results,
the use of a unit hydrograph method shall be made. The use of a unit
hydrograph calculation will be based upon standard and accepted engineering
principles subject to the approval of the City Engineer. Acceptable
methods include the Soil Conservation Service (SCS) Technical Release
Number 55 or the Corps of Engineers HEC-1 models for drainage areas
two hundred (200) acres or more.
ii) The unit hydrograph method shall be based upon fully developed watershed
conditions assuming no effects from the small on-site detention facilities
for maintaining the rate of runoff as if the property was developed
as single-family residential use. The detention effects of large regional
detention facilities can be taken into account in unit hydrograph
methods.
iii) Circumstances that may require the use of a unit hydrograph method
include sizing open channels, reclaiming floodplains, creating lakes,
or building other types of drainage-related facilities on major drainage
courses. Design engineers of these types of facilities should be aware
that the requirement of designing for fully developed watershed conditions
will mean that they will have to calculate these fully developed flows
instead of using the flows calculated in the Federal Emergency Management
Agency’s (FEMA) flood insurance studies for Overton or Rusk/Smith
County.
204.3 Design
storm frequencies.
The approved drainage system shall
provide for positive overflow at all low points. The term “positive
overflow” means that when the inlets do not function properly
or when the design capacity of the conduit is exceeded, the excess
flow can be conveyed overland along a grassed or paved course. Normally,
this would mean along a street or alley, or shall require the dedications
of special drainage easements on private property.
DRAINAGE FACILITY
|
DESIGN RECURRENCE INTERVAL
|
---|
Closed Storm Sewer Systems
|
10-year with 100-year positive overflow in streets such that
the depth of flow in the street does not exceed the top of curb.
|
Closed Storm Sewer Systems and Inlets at Street Low Point or
Sag
|
100-year with positive overflow
|
Culverts and Bridges
|
100-year
|
Concrete-lined Channels
|
100-year
|
Earthen Channels
|
100-year
|
204.4 Street
and alley capacity.
1. The depth
of flow in the streets shall not exceed the top of curb for the one-hundred-year
storm.
2. The flows
created by the one-hundred-year storm shall be contained within the
capacity of all paved alleys.
3. The first-floor
elevations of all residential and other structures shall be set at
a minimum elevation of one (1) foot above the top of the street curb
elevation or the alley invert, and with positive drainage provided
away from the structure. Positive overflow sections shall provide
a minimum of one (1) foot of freeboard from the overflow invert adjacent
to structures and the corresponding first floor elevation of all residential
and other structures.
204.5 Inlet
placement and capacity.
1. Storm
sewer inlets shall be built along paved streets at such intervals
that the depth of flow, based upon the one-hundred-year storm, does
not exceed the top of curb. Inlets shall be located as necessary to
remove the flow based on a ten-year storm. If in the opinion of the
City Engineer the flow in the gutters would be excessive using the
above design criteria, the storm sewers or inlet locations could be
altered to relieve adverse conditions.
2. Inlets
shall be placed upstream from an intersection whenever possible. At
any intersection, only one (1) street shall be crossed with surface
drainage and this street shall be the lower classified street. When
an alley intersects a street, inlets shall be placed in the alley
whenever flow down that alley would cause the capacity of the intersecting
street to be exceeded.
3. The minimum
inlet size shall be five (5) feet. No more than twenty (20) feet of
inlet shall be placed along one (1) gutter at any given location.
Minimum sizes of laterals shall be eighteen (18) inches for use with
five-foot inlets, twenty-one-inch laterals with ten-foot, fourteen-foot,
and drop inlets and twenty-four-inch laterals for twenty-foot inlets.
Where laterals tie into trunk lines, place the laterals on a sixty-degree
angle with the trunk line and connect them so that the longitudinal
centers intersect.
204.6 Pipe
design standards.
1. Storm
sewer conduit shall be sized to flow full. Manning’s Equation
shall be used to determine the conduit size.
2. Minimum
and Maximum Velocities in Pipes.
i) The
minimum velocities in conduit shall be two and one-half (2.5) feet
per second.
ii) Maximum velocity in the pipe shall not exceed twelve (12) feet per
second.
iii) The maximum discharge velocities in the pipe shall also not exceed
the permitted velocity of the receiving channel or conduit at the
outfall to prevent erosive conditions. The maximum outfall velocity
of a conduit in partial flow shall be computed for partial depth and
shall not exceed the maximum permissible velocity of the receiving
channel unless controlled by an appropriate energy dissipater (e.g.
stilling basins, impact basins, riprap protection).
3. In general,
storm water shall be carried in concrete pipe conduit, but other types
of conduit can be used to carry storm water. However, prior permission
to use other conduit materials must be obtained from the City Engineer.
4. Hydraulic
Gradient.
i) Conduits
must be sized, and slopes must be set such that runoff flows smoothly
down the drainage system. To insure this smooth passage, the hydraulic
gradient must be at the proper elevations. The hydraulic grade line
shall be established and shown on the plans for all storm sewer design.
ii) The hydraulic grade line shall in no case be closer to the surface
of the ground or street than one (1) foot.
iii) Hydraulic gradient calculations shall account for all head losses that may occur in the storm sewer line. Friction head loss shall be determined by direct application of Manning’s Equation. Minor losses due to turbulence at structures shall be determined using Appendix
C - Minor Head Losses of this section.
204.7 Culvert
design.
1. One (1)
foot of freeboard is required between the one-hundred-year water surface
elevation and the top of curb elevation. Exceptions must be approved
in writing by the City Engineer.
2. Culverts
must be designed using standard methods and engineering judgment.
Culverts shall be designed in accordance with the latest edition of
the Texas Department of Transportation (TxDOT) Hydraulic Design Manual.
Standards of the City of Overton will take precedence over TxDOT Manual
in cases of conflict.
3. Culvert
hydraulic grade line calculations shall consider both inlet and outlet
control.
4. Culverts
shall be skewed such that impacts due to the flood and normal flow
angles of attack on the structure are minimized.
5. The maximum
velocity through a culvert shall be fifteen (15) feet per second.
6. Stream
stability shall be assessed when determining the number of barrels,
height and width and culvert skew. Potential for scour shall be accounted
for in the design.
204.8 Bridges.
1. Two (2)
feet of freeboard is required between the one-hundred-year water surface
elevation and the low chord of the bridge. Exceptions to this requirement
must be approved by the City Engineer in writing.
2. The skew
of the bridge piers and abutments shall be oriented as close to the
normal or flood direction of flow resulting in an angle of attack
as close to zero (0) degrees as possible.
3. Bridges
shall be designed using standard methods.
4. Stream
stability shall be assessed when designing the abutments and interior
bents of the bridge. Scour shall be accounted for in the design.
204.9 Channels.
1. Open
channels are discouraged in urban areas. Open channels may be used
instead of an enclosed system when the pipe size, necessary to carry
the design storm event, exceeds the capacity of two- to sixty-inch
RCP. Open channels shall not be permitted when two- to sixty-inch
RCP pipes will carry the design flow, unless approved by the City
Engineer.
2. Open
channel design criteria:
i) Channels
may be left in their natural state provided that the channel velocities
are six (6.0) feet per second or less and that one (1) foot of freeboard
is available during the design storm event.
ii) If the natural channel is to be replaced by an improved channel,
the flow from the one-hundred-year design flood must be contained
within the improved channel while allowing for one (1) foot of freeboard.
iii) Improved channels shall be trapezoidal shaped and include a lined
section if the design velocity is greater than six (6) feet per second.
Lining types such as concrete, rock walls and gabions may be used
upon approval of the City Engineer. The maximum velocity allowed in
concrete-lined channels is fifteen (15) feet per second.
iv) Unless shown to be feasible in a soils report sealed by a licensed
professional engineer in the State of Texas and approved by the City
Engineer, improved channels shall have minimum side slopes of:
a) Four (4) feet horizontal to one (1) foot vertical for earthen, grassed-lined
side slopes.
b) One and one-half (1.5) feet horizontal to one (1) foot vertical for
concrete-lined side slopes in rock.
v) Where
practicable, all unpaved channels should have sufficient grade to
avoid ponding during backwater flow conditions. A minimum slope of
0.40 percent is required for earthen channels and swales, except those
used as part of a wetlands area.
vi) The developer or owner shall use low maintenance vegetation for vegetative
cover, as approved by the City Engineer prior to planting. The selection
of materials shall comply with the current ground cover listing for
North Central Texas furnished through the Texas Agricultural Extension
Service.
3. Manning’s
equation can be used to design channels and determine water surface
elevations and velocities when backwater effects are negligible. Channels
where backwater effects occur must be designed using models accepted
by FEMA.
4. All channel
sections must consider and account for channel stabilization in their
design. This requirement pertains to all sections whether they are
left in their natural condition or are modified in any manner. The
design of all drainage channels and swales shall assure adequate capacity
and minimum maintenance to overcome the result of erosion, silting,
sloughing of bends or similar occurrences.
5. When
performing hydraulic analyses for channel or drainageway design, the
starting water surface shall be based on the following criteria:
i) When
the ratio of the drainage area of the receiving creek (at the confluence
location) to the drainage area of the channel or drainageway being
designed is fifteen (15) or greater, the ten-year water surface of
the receiving creek shall be used as the starting water surface for
hydraulic design calculations. For creeks where the ten-year water
surface is not available, the slope-area method will be used for starting
design calculations.
ii) When the ratio of the drainage area is less than fifteen (15), the
one-hundred-year elevation on the receiving creek shall be used as
the starting water surface for design calculations.
204.10 Detention design.
Detention/retention
facilities shall be designed for the one-hundred-year design flood
according to the following criteria:
1. Dedicated
detention/retention basins shall also include an additional one (1)
foot of freeboard and two (2) feet of sediment storage. The volume
of runoff storage for drainage areas greater than two hundred (200)
acres shall be computed using unit hydrograph procedures. Unit hydrograph
calculations shall be signed and sealed by an Professional Engineer
licensed in the State of Texas.
For drainage areas less than two hundred (200) acres, the above
methods are recommended; however, an approximate routing method based
on the rational formula is allowable.
2. All
detention facilities designed shall consider the timing of the flood
peak in the main channel into which the detention facility drains.
Delaying the peak from a site in lower portions of a watershed may
result in a higher peak on the main channel.
3. A detention
facility shall have enough gradient to ensure positive drainage to
the outlet structures so as to avoid nuisance conditions such as standing
water, odors, insects, and weeds. A minimum slope of 0.40 percent
towards the outlet structure is required for all detention facilities.
4. Detention
areas in parking lots shall not be:
i) In
required parking spaces but in extra spaces.
ii) Behind speed bumps unless the speed bumps are made with reinforced
concrete.
iii) Deeper than six (6) inches unless otherwise approved by the City
Engineer and warning signs shall be posted.
5. Drainage
easements shall be provided for all regional detention/retention facilities
and for other detention/retention facilities where two (2) or more
owners are involved.
6. Detention
facilities shall be designed to empty in less than twenty-four (24)
hours, unless it is also serving as an erosion control facility.
7. Detention
facilities used as a sediment control device shall meet the following
requirements:
i) The
sediment control facility shall be designed with minimal velocities
such that sediment is dropped and not picked up by flows at any time
during the storm event.
ii) The basin shall be designed with adequate sediment storage area so
that sediment removal is not required more than twice a year. Expected
removal periods greater than twice a year must be specified in the
maintenance plan and approved by the City Engineer.
iii) Sediment control facilities cannot be used to meet detention requirements
unless the volume of sediment is included in the calculations for
the detention basin design.
8. The
owner shall maintain detention/retention facilities unless the facilities
are dedicated to the City of Overton. The following measures are required
to ensure the facility functions properly.
i) Facilities
should be mowed at least twice a year to control weeds and discourage
woody growth.
ii) Debris, litter and accumulated sediment should be removed from detention
facilities at least twice a year. Particular attention should be given
to removal of debris, litter and sediment around outlet structures.
iii) Detention basins designed for sediment removal shall be maintained
as specified in the maintenance plan and approved by the city with
construction plan submittal.
204.11 Flumes.
The use of flumes is not recommended for widespread
use. Flumes shall not be permitted when the purpose of a permanent
flume is to carry runoff down the sides of earthen channels. A flume
may be used to direct overflow runoff along property lines until the
runoff can be intercepted by streets or conduits. Flumes crossing
sidewalks shall be covered or bridged such as to minimize danger to
pedestrians.
204.12 Residential grading and drainage.
1. Surface
runoff from residential lots shall cross no more than one (1) additional
lot before being directed toward the street or a dedicated drainage
system. When the flow reaches the second lot, side lot swales shall
be in place to direct the flows to the street or to a dedicated city
drainage system within an easement in the rear yard. Furthermore,
no more than one (1) lot may drain to a second lot before the flow
is directed to a street or to a dedicated city drainage system. Where
lot-to-lot drainage occurs, the lot lines shall be aligned and a dedicated
private drainage easement shall be provided.
2. Three
(3) general categories of residential lot grading and drainage plans
are anticipated within the City of Overton as shown below. In all
cases, appropriate design storm calculations shall be required including
capacity of all existing and proposed drainage infrastructure and
receiving waters. Specific deviations from these three (3) plans will
be considered on an individual basis.
i. Single
residential lot grading with drainage directly to dedicated infrastructure
including drainage easement, public road, existing waterway, or public
drainage infrastructure.
ii. Multiple lot residential grading with drainage to dedicated infrastructure
including drainage easement, public road, existing waterway, or public
drainage infrastructure.
iii. Single or multiple lot residential grading with drainage directed
to required on-site detention infrastructure.
3. When
adjacent to the floodplain, the finished floor (FF) elevation of commercial
buildings shall be one (1) foot above the one-hundred-year fully developed
water surface elevation (WSE) of the ultimate floodplain. The FF elevation
of residential buildings shall be two (2) feet above the one-hundred-year
fully developed water surface elevation (WSE) of the ultimate floodplain.
(Ordinance 2018.04.19B adopted 4/19/18)