A. Approval
required by Johnson County Special Utility District or Bethesda Water
Supply Corporation. All water and wastewater improvements shall conform
to the Johnson County Special Utility District or Bethesda Water Supply
Corporation regulations.
(Ordinance 797-2020 adopted 10/15/20; Ordinance
871-2023 adopted 9/21/2023)
A. Generally.
An adequate storm sewer system consisting of inlets, pipes,
channel improvements or grading, driveway adjustments, or other underground
structures with approved outlets shall be constructed where runoff
of stormwater and the prevention of erosion cannot be accomplished
satisfactorily by surface drainage facilities. Areas subject to flood
conditions or inadvertent stormwater retention, such as standing or
pooling water, as established by the City Engineer, will not be considered
for development until adequate drainage has been provided. Drainage
systems, including all conveyances, inlets, conduits, structures,
basins, or outlets used to drain stormwater, must be designed and
constructed to promote the health, safety, and welfare of the property
owner and the public. Adequate provision must be made for the acceptance,
collection, conveyance, detention, and discharge of stormwater runoff
drainage onto, through, and originating within the subdivision. Stormwater
must be discharged in an acceptable form and at a controlled rate
so as not to endanger human life or public or private property.
B. Design Criteria.
The criteria for use in designing storm sewers, culverts, bridges,
drainage channels, and drainage facilities shall conform to the EDSS.
In no case shall drainage areas be diverted artificially to adjacent
properties or across roadways. All storm drainage facilities must
be designed and constructed to safely drain a fully-developed 100-year
return frequency flood as outlined in the EDSS, as amended.
C. Lot to Lot
Drainage.
Stormwater drainage from one lot onto another
shall not be allowed unless such drainage poses no harm or inconvenience
to the downstream property owner(s), unless specifically approved
by the City Engineer, and unless the necessary off-site drainage easements
are procured on the affected properties, or if applicable, where drainage
appears to cause harm and inconvenience, letters of permission from
the property owner have been obtained and approved by the City.
D. Developer
Responsibilities.
The developer shall ensure that all
drainage improvements within public easements or rights-of-way are
functioning properly prior to the expiration of the maintenance bond.
The developer shall be responsible for removing any significant build-up
of sediment or debris from drainage improvements, with the exception
of backlot and side lot drainage swales, at the eleventh month of
the second year for the required two-year maintenance bond for the
applicable facilities. The City shall inspect the improvements to
determine any maintenance or correction of deficiencies at the conclusion
of this period.
E. Layout Requirements.
To reduce stormwater runoff, and resulting erosion, sedimentation
and conveyance of nonpoint source pollutants, the layout of the street
network, lots and building sites shall, to the greatest extent possible,
be sited and aligned to minimize the amount of cut and fill on slopes
in order to minimize the amount of land area that is disturbed during
construction. All erosion and sedimentation controls shall conform
to the EDSS.
F. Runoff.
No proposed development shall be constructed which impedes or
constricts runoff from an upstream watershed.
G. Floodplain.
Land subject to flooding, as designated in a FEMA 100-year floodplain,
shall not be platted for residential occupancy, nor shall it be platted
for such other uses as may increase danger to health, life or property
or aggravate the flood hazard. Lots may be platted which include designated
floodplain; however, the lot must contain sufficient buildable area
outside of the designated floodplain, based on current zoning requirements.
H. Detention
and Retention Ponds.
Detention or retention ponds shall
be required to limit the peak rate of discharge to rates which will
not cause an increase in flooding or channel instability downstream
when considered in conjunction with ultimate watershed development
and downstream drainage capacities. Design of the pond shall be in
accordance with the criteria established in the EDSS.
I. Funding.
The owner or developer shall fund and construct all storm drainage
outfalls necessary to safely and adequately drain the development.
J. Creeks and
Drainage Areas.
All creeks and drainage areas shall be
preserved and protected in their natural condition wherever possible.
All development adjacent to creeks and drainage areas shall be in
accordance with the City’s EDSS, and with any other City policies
or ordinances related to public access or recreational use of waterways.
Sheet flow into drainage channels or creeks shall be limited to non-erosive
velocities as determined in the EDSS.
K. Bridges.
Bridges or culverts shall be constructed at all street locations
where flow patterns cross the street and are not intercepted by an
underground storm sewer system or appropriate concrete valley gutter.
(Ordinance 797-2020 adopted 10/15/20)
A. Generally.
Fire hydrants with valves shall be installed at each street
intersection and at a minimum of five hundred foot (500') spacing
in any residential subdivision and three hundred foot (300') spacing
in all other zones. Additional fire hydrants shall be placed as necessary
such that all ground portions of all buildings in the subdivision
can be reached with a normal three hundred foot (300') lay of fire
hose. In most instances, commercial buildings will be required to
have fire suppression systems and fire spigots in addition to the
normal fire hydrants.
B. Specifications.
1. Fire hydrants
shall be located no further than fifteen feet (15') from a street
or fire lane, except as approved by the City based on feasibility.
2. Fire lanes
shall not be narrower than twenty-four feet (24').
3. Blue pavement
reflectors, meeting the criteria of the fire department, shall be
installed at the center of the street(s) adjacent to each fire hydrant
location.
C. Blocking.
Fire hydrants, valves and pipe ends shall be blocked with unreinforced
concrete of at least 2,500 pounds per square inch (psi) as shown in
the City’s standard water details in the EDSS. If the EDSS does
not provide standards for blocking for a particular situation, then
the North Central Texas Council of Governments (NCTCOG) details shall
be met. In no instance shall rocks be in contact with the pipe or
fittings.
(Ordinance 797-2020 adopted 10/15/20)