A Floodplain Development Permit as established in Section 39.05.009, Floodplain Development Permit, is required to ensure conformance with this Division.
(Ordinance 2023-O0054 adopted 5/9/2023)
In all areas of special flood hazards the following provisions are required for all new construction and substantial improvements:
a.
Anchoring.
All new construction or substantial improvements shall be designed or modified and adequately anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrostatic pressure, hydrodynamic and hydrostatic loads, including the effects of buoyancy;
b.
Methods and practices.
All new construction or substantial improvements shall be constructed by methods and practices that minimize flood damage;
c.
Materials.
All new construction or substantial improvements shall be constructed with materials resistant to flood damage;
d.
Infiltration.
All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems;
e.
Sanitary sewers.
New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharges from the systems into floodwaters;
f.
On-site waste disposal.
On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding; and
g.
Utilities.
All new construction or substantial improvements shall be constructed with electrical, heating, ventilation, plumbing, air conditioning equipment, and other service facilities that are designed or located to prevent water from entering or accumulating within the components during conditions of flooding (above the base flood elevation).
(Ordinance 2023-O0054 adopted 5/9/2023)
a.
Generally.
In all areas of City Floodplain and special flood hazard where base flood elevation data is provided, as set forth in this Section, the following provisions apply.
b.
Residential construction.
New construction and substantial improvement of any residential structure shall have the lowest floor (including basement), electrical, heating, ventilation, plumbing, air conditioning equipment, and other service facilities, including ductwork, elevated to the most restrictive flood protection elevation as set forth below.
1.
Lowest floor elevation.
A.
One foot above the one percent annual chance flood elevation established by the City of Lubbock Master Drainage Plan;
C.
Two feet above the applicable playa lake overflow elevation;
E.
Six inches above the calculated peak water surface elevation if a design waiver is granted in accordance with the Drainage Criteria Manual; or
F.
One foot above the 500-year 24-hour base flood elevation if located within the limits of a non-overflow playa lake.
2.
Certification. A registered professional engineer, architect, or land surveyor shall submit a certificate to the Floodplain Administrator that the standard of this Subsection, as provided in Subsection b.1 of this Subsection, is satisfied.
c.
Nonresidential construction.
New construction and substantial improvement of any commercial, industrial, or other nonresidential structure shall have the lowest floor (including basement and associated electrical and mechanical equipment) elevated to or above:
1.
Lowest floor elevation. If located in a flood hazard area, the lowest floor (including basement) will be one foot above the peak water surface elevation established by the FIRM of FEMA.
2.
Playa lake overflow. Two feet above the applicable playa lake overflow elevation.
4.
Peak water surface elevation. Six inches above the calculated peak water surface elevation if a design waiver is granted in accordance with the Drainage Criteria Manual.
5.
Five-hundred-year flood. One foot above the 500-year 24-hour base flood elevation if located within the limits of a non-overflow playa lake or together with attendant utility and sanitary facilities, be designed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.
6.
Record. A record of that certification (floodproofing certificate), which includes the specific elevation (in relation to mean sea level) to which the structures are floodproofed, shall be maintained by the Floodplain Administrator.
7.
Grading design. A finished floor elevation may be set in conjunction with a Grading Plan prepared by a licensed professional engineer that shows adequate drainage paths away from the site and with confirmation that no other flooding influences the subject site.
d.
Enclosures.
1.
Design. New construction and substantial improvements with fully enclosed areas below the lowest floor that are usable solely for parking of vehicles, building access, or storage in an area other than a basement and which are subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters.
2.
Certification. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or meet or exceed the following minimum criteria:
A.
A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided.
B.
The bottom of all openings shall be no higher than one foot above grade.
C.
Openings may be equipped with screens, louvers, valves, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.
e.
Manufactured homes.
1.
All manufactured homes to be placed or substantially improved within zone A, AO, AH, or AE on the City's FIRM and within City Floodplains on sites that are in the following locations shall be placed on a permanent foundation so that the lowest floor of the manufactured home, electrical, heating, ventilation, plumbing, air conditioning equipment, and other service facilities, including ductwork shall be elevated to the most restrictive flood protection level as set for above:
A.
Outside of a manufactured home park or subdivision;
C.
Existing manufactured home park or subdivision being enlarged; or
D.
In an existing manufactured home park or subdivision in which the manufactured home has incurred substantial damage as a result of a flood or other causes.
2.
In addition, all manufactured homes to be placed or substantially improved within zone A, AO, AH, or AE on the City's FIRM and within City Floodplains on sites that are in the locations listed in Subsections A through D, above. shall be securely anchored to an anchored foundation system to resist flotation, collapse, and lateral movement, including, but not limited to over the top or frame ties to ground anchors, while complying with all other state and local regulations. Submit FEMA Elevation Certificate and engineering foundation report showing the flood protection level is satisfied.
3.
Special flood hazard areas. If located in a Special Flood Hazard Area (SFHA), the lowest floor (including basement) shall be elevated to or above the most stringent of the following:
A.
One foot above the 500-year 24-hour base flood elevation if located within the limits of a non-overflow playa lake.
B.
Six inches above the calculated peak water surface elevation if a design waiver has been granted in accordance with the Drainage Criteria Manual;
D.
Two feet above the applicable playa lake overflow elevation; or
E.
One foot above the peak water surface elevation established by the FIRM;
4.
Manufactured home otherwise exempted from section. Manufactured homes that are placed or substantially improved on sites in an existing manufactured home park or subdivision within a SFHA on the community's FIRM that are not subject to the provisions in this Section shall be elevated so that either:
A.
The lowest floor (including basement) of the manufactured home is 12 inches above the base flood elevation; or
B.
The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than 36 inches in height above grade and be securely anchored to an adequately engineered anchor foundation system to resist flotation, collapse, and lateral movement.
f.
Recreational vehicles.
Recreational vehicles placed on sites within zones of SFHA on the community's FIRM shall:
g.
Playa lakes.
Playa lakes provide critical water storage and drainage functions. All new construction and substantial improvement of structures shall follow the provisions in Division 5.3, Playa Lakes Development and Ownership.
(Ordinance 2023-O0054 adopted 5/9/2023)
a.
Generally.
All subdivision proposals, including the placement of manufactured home parks and subdivisions, shall be consistent with this Section.
b.
Floodplain development permit.
All proposals for the development of subdivisions, including the placement of manufactured home parks and subdivisions, shall meet Floodplain Development Permit requirements of Division 5.1, Flood Damage Prevention.
c.
Adequate drainage.
All subdivision proposals, including the placement of manufactured home parks and subdivisions, shall have adequate drainage provided to reduce exposure to flood hazards.
d.
Utilities.
All subdivision proposals, including the placement of manufactured home parks and subdivisions, shall have public utilities and facilities such as water, wastewater, and systems located and constructed to minimize or eliminate flood damage.
(Ordinance 2023-O0054 adopted 5/9/2023)
a.
Generally.
Located within areas of special flood hazard established in this Division are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and erosion potential, the following provisions apply.
b.
Encroachments.
Encroachments are prohibited, including fill, new construction, substantial improvements, and other development within the adopted regulatory floodway unless it has been demonstrated through hydrologic and hydraulic analyses performed by a registered professional engineer in accordance with standard engineering practice that the proposed encroachments would not result in any increase in flood levels within the City during the occurrence of the base flood discharge.
c.
New construction.
If Subsection b., Encroachments,is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this Division.
(Ordinance 2023-O0054 adopted 5/9/2023)
Table 39.05.016-1, SI/SD FEMA Desk Reference, outlines common improvements and repairs. The measures as described in Table 39.05.016-1 are required to maintain compliance with the NFIP floodplain management requirements. If a map revision has resulted in a higher base flood elevation (BFE), a post-FIRM building shall comply based on the new BFE. Table 39.05.016-1, SI/SD FEMA Desk Reference, is reprinted and edited from SI/SD FEMA Desk Reference as amended.
Table 39.05.016-1 SI/SD FEMA Desk Reference | ||
|---|---|---|
SI = Substantial Improvement | SD = Substantial Damage | ||
Types of Work | Building is Pre-FIRM | Building is Post-FIRM |
Rehabilitation (renovate or remodel), not SI | Compliance not required | |
Rehabilitation (renovate or remodel), SI | Building required to comply | |
Lateral addition and rehabilitation, SI | Addition required to comply; building required to comply | Addition required to comply; building required to comply (see note below table) |
Lateral addition, not SI | Addition not required to comply | Additional required to be elevated to or at least the elevation of the existing lowest floor |
Lateral addition, SI, not structurally connected | Addition required to comply; building not required to comply | Addition required to comply; building required to comply |
Lateral addition, SI, structurally connected | Addition required to comply; building required to comply | Addition required to comply; building required to comply (see note below table) |
Compliance not required | ||
Building required to comply | ||
Repair foundation, not SI | Compliance not required | |
Repair foundation, SI | Building required to comply | Building required to comply (see note below table) |
Replace/extend foundation, SI (including "elevate-in-place") | Building required to comply | Building required to comply (see note below table) |
Repair damage, SD | Building required to comply | |
Reconstructed building required to comply | Reconstructed building required to comply (see note below table) | |
TABLE NOTES: | |
1 | Maintain existing floor elevations. Floor elevations shall not be lowered by improvements. |
(Ordinance 2023-O0054 adopted 5/9/2023)