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)