Chapter 18.75
FLOOD PLAIN OVERLAY ZONE – FPO
Sections:
18.75.020 General requirements.
18.75.050 Permitted uses within the FPO (A1 – 30) primary flood hazard subzone.
18.75.060 Permitted uses within the FPO (AO) shallow flood subzone.
18.75.070 Permitted uses within the FPO (f) floodway subzone.
18.75.080 Development standards.
18.75.100 Water and sewer facilities.
18.75.010 Intent.
The FPO Flood Plain Overlay Zone has been established to provide an environment, in and around those portions of the community subject to periodic flooding, which will protect life and minimize property losses from such flooding. More specifically the objectives of the Flood Plain Overlay Zone are:
A. To protect human life and health.
B. To minimize public and private property damage.
C. To minimize surface and groundwater pollution which affects human, animal, or plant life.
D. To warn individuals against constructing buildings in high flood hazard areas.
E. To control development which will, when acting alone or in combination with similar development, create an additional burden to the public to pay the costs of rescue, relief, emergency preparedness measures, sandbagging, pumping, and temporary dikes or levees. [Ord. 2010-5. Code 1988 § 11-5-10.1].
18.75.020 General requirements.
Below are general requirements for any development within any of the city’s flood plain zones.
A. Relocation of Watercourse.
1. Any proposed alteration or relocation of the channel of any designated floodway shall be first approved by the city council. No such alteration or relocation shall have the effect of reducing the water carrying capacity of the floodway.
2. Prior to granting approval for alteration or relocation the city engineer shall notify all adjacent local governments and the State Coordinator and submit copies of the notifications to the Federal Insurance Administration.
B. Warning and Disclaimer of Liability. The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on engineering and scientific methods of study. Larger floods may occur on rare occasions or flood heights may be increased by manmade or natural causes, such as ice jams and bridge openings restricted by debris. This chapter does not imply that areas outside the flood plain zones or land uses permitted within such zones will be free from flooding or flood damages. This chapter shall not create liability on the part of the city or any officer or employee thereof for any flood damages that result from reliance on this chapter or any administrative decision lawfully made thereunder.
C. Development Standards Amendments. The city may, from time to time, adopt standards and specifications relating to the design and quality of required improvements within flood plain areas and the administration of flood regulations. All developments shall be carried out in accordance with these adopted standards and specifications. [Ord. 2010-5. Code 1988 § 11-5-10.2].
18.75.030 Administration.
A. Development Permit Required. Any person, firm or corporation desiring to construct, add to, or move a dwelling or other structure, or proposing to excavate or place fill or other form of development within the boundaries of the FPO Zone, shall first make application for and obtain a development permit from the planning commission before starting construction. Said application shall be made on forms furnished by the city.
B. Interpretation of Flood Plain Boundaries. Precise boundaries of the flood plain shall be determined by scaling distances on the official Flood Plain Zone Map; provided, however, where there is a disagreement as to the determination made by the planning commission or where it is determined that an interpretation is desirable, i.e., an apparent conflict between the map boundary and actual field conditions, the appeal authority shall, upon appeal, make the necessary interpretation in accordance with HMC 18.15.170.
Any such appeal shall be made in accordance with all applicable procedures and conditions related to appeals before the proper appeal authority.
In making its determination the appeal authority shall utilize all technical evidence available to it including the detailed data contained within the flood insurance study. See also Section 10-9a-703, Utah Code Annotated 1953, as amended.
C. Base Flood Elevations. Where base flood elevations have not been determined, the zoning administrator is hereby directed to utilize existing data from any federal, state or local sources to assist in determining said elevations. [Ord. 2010-5. Code 1988 § 11-5-10.3].
18.75.040 Permitted uses.
All permitted uses shall be subject to the following:
A. No structure, fill, development or encroachment shall be permitted which would result in an increase in flood levels during a base flood.
B. All development, which is permitted within a subzone, shall comply with the specific requirements for development in the FPO (A1 – 30) and (AO) subzones as set forth in this chapter or regulations adopted pursuant hereto.
C. All bridges or flood control structures shall be first approved by the city council. [Ord. 2010-5. Code 1988 § 11-5-10.4].
18.75.050 Permitted uses within the FPO (A1 – 30) primary flood hazard subzone.
Permitted uses within this subzone shall include all uses permitted within the underlying zone subject to compliance with all requirements for development in flood plain areas as set forth in this chapter or regulations adopted pursuant hereto.
A. Specific Requirements in FPO (A1 – 30) Subzone. All new construction and all improvement of any existing structure which will equal or exceed 50 percent of the value of the existing structure shall:
1. Have the lowest floor (including basement) elevated on compacted fill, or a continuous concrete foundation to or above the base flood elevation; or
2. Have all portions of the structure and attendant sanitary and utility facilities located at a level which is two feet above the base flood level flood-proofed. Said flood-proofing measures shall be in accordance with city standards where such have been adopted by the city and approved by the Federal Insurance Administration, or else be certified by a registered engineer as adequate to withstand flood depths, pressure, velocity, impact and uplift arising from a base flood; provided, that this option shall not be applicable to structures used as a residence except when approved by the appeal authority in accordance with the provisions of HMC 18.15.170; or
3. Have been exempted from the necessity of compliance with the requirements of the FPO Zone as evidenced by a letter of map amendment or conditional commitment letter from the Federal Insurance Administration, or by action of the appeal authority in interpreting the boundaries of the FPO Zone. [Ord. 2010-5. Code 1988 § 11-5-10.4a].
18.75.060 Permitted uses within the FPO (AO) shallow flood subzone.
Permitted uses within this subzone shall include all uses permitted within the underlying zone subject to compliance with all requirements for development in flood plain areas as set forth in this chapter or regulations adopted pursuant hereto.
A. Specific Requirements in FPO (AO) Subzone. All new construction and all improvement of any existing structure which will equal or exceed 50 percent of the value of the existing structure shall:
1. Have the lowest floor (including basement) elevated on compacted fill, or a continuous concrete foundation to or above the base flood elevation; or
2. Have all portions of the structure and attendant sanitary and utility facilities located at a level which is two feet above the base flood level flood-proofed. Said flood-proofing measures shall be in accordance with city standards where such have been adopted by the city and approved by the Federal Insurance Administration, or else be certified by a registered engineer as adequate to withstand flood depths, pressure, velocity, impact and uplift arising from a base flood; provided, that this option shall not be applicable to structures used as a residence except when approved by the appeal authority in accordance with HMC 18.15.170; or
3. Have been exempted from the necessity of compliance with the requirements of the FPO Zone as evidenced by a letter of map amendment or conditional commitment letter from the Federal Insurance Administration, or by action of the appeal authority in interpreting the boundaries of the FPO Zone. [Ord. 2010-5. Code 1988 § 11-5-10.4b].
18.75.070 Permitted uses within the FPO (f) floodway subzone.
Permitted uses within this subzone shall include all uses permitted within the underlying zone, except that no dwelling or other structure used for human occupancy shall be permitted. [Ord. 2010-5. Code 1988 § 11-5-10.4c].
18.75.080 Development standards.
All construction and development within the FPO Zone shall be carried out in accordance with the following standards and specifications for development in flood plain areas.
A. Buildings or structures shall have a low flood damage potential.
B. The buildings or structures shall be constructed and placed on the building site so as to offer the minimum obstruction to the flood or flood waters.
C. All buildings and structures shall be constructed with flood resistant materials and utility equipment and be constructed using methods and practices that minimize flood damage.
D. So far as practicable, buildings or structures shall be placed approximately on the same flood flow lines as those of adjoining structures.
E. Location of any structural storage facilities for chemical, explosives, buoyant materials, flammable liquids, or other toxic materials which could be hazardous to public health, safety and welfare shall be accomplished in a manner which will assure that the facilities are situated above the base flood elevation or are flood-proofed to prevent flotation or storage containers which could result in the escape of toxic materials into flood water.
F. All new structures and all additions to existing structures shall be anchored to prevent flotation, collapse or lateral movement of the structure.
G. Development permits for the proposed construction or improvements shall be obtained from federal, state or local government agencies from which prior approval is required. [Ord. 2010-5. Code 1988 § 11-5-10.5].
18.75.090 Special requirements for mobile homes and similar structures not tied to a permanent foundation.
All mobile homes and similar structures to be placed within the FPO (A1 – 30) or FPO (AO) subzone shall be anchored to resist flotation, collapse, or lateral movement by providing over-the-top and frame ties to ground anchors as follows:
A. Over-the-top ties shall be provided at each of the four corners of the mobile home, with two additional ties per side at intermediate locations. Mobile homes less than 50 feet long shall require only one additional tie per side;
B. Frame ties shall be provided at each corner of the mobile home with five additional ties per side at intermediate points. Mobile homes less than 50 feet long shall require only four additional ties per side;
C. All components of the anchoring system shall be capable of withstanding a force of 4,800 pounds; and
D. Any additions to the mobile home shall be similarly anchored. [Ord. 2010-5. Code 1988 § 11-5-10.6].
18.75.100 Water and sewer facilities.
Water and sewer facilities within the FPO Zone shall be designed and constructed to minimize flood hazard as follows:
A. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system.
B. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharge from the systems into flood waters; and
C. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding. [Ord. 2010-5. Code 1988 § 11-5-10.7].