§ 10-13C-4 Additional Requirements for Development in the Flood Hazard Area – Provisions for Flood Hazard Reduction

10-13C-4: ADDITIONAL REQUIREMENTS FOR DEVELOPMENT IN THE FLOOD HAZARD AREA – PROVISIONS FOR FLOOD HAZARD REDUCTION:

A. Application: In addition to the general requirements for development or zone changes in a flood hazard area, all development in the flood hazard area shall meet the following additional requirements for flood hazard reduction: The general standards set out in subsections B through E of this section are required. In areas of special flood hazard where base flood elevation data has been provided as set forth in section 10-13C-1, or hazard determination has been made by the city engineer or designee pursuant to section 10-13C-3D, the specific standards of subsection F of this section are also required.

1. All new construction and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure and make it capable of resisting hydrostatic and hydrodynamic loads;

2. All manufactured homes shall be elevated and anchored to resist flotation, collapse or lateral movement and be capable of resisting hydrostatic and hydrodynamic loads. Methods of anchoring may include, but are not limited to, the use of over-the-top or frame ties to ground anchors. This requirement is in addition to applicable state and local anchoring requirements for resisting wind forces. Specific requirements are:

a. Over-the-top ties shall be provided at each of the four (4) corners of the manufactured home, with two (2) additional ties per side at intermediate locations; with manufactured homes less than fifty feet (50') long requiring one (1) additional tie per side;

b. Frame ties shall be provided at each corner of the home with five (5) additional ties per side at intermediate points; with manufactured homes less than fifty feet (50') long requiring four (4) additional ties per side;

c. All components of the anchoring system shall be capable of carrying a force of four thousand eight hundred (4,800) pounds; and

d. Any additions to the manufactured home shall be similarly anchored;

a. All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage;

b. All new construction and substantial improvements shall be constructed using methods and practices that minimize flood damage.

C. All new construction and substantial improvements shall be constructed with electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities that are designed and/or located to prevent water from entering or accumulating within the components during conditions of flooding.

1. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system;

2. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the systems, and minimize or eliminate discharge from the systems into flood waters; and

3. On-site waste disposal systems shall be located to avoid impairment to them, or contamination from them, during flooding.

1. All new development proposals, including subdivisions, located within an erosion hazard area shall be consistent with the need to minimize erosion damage. Proposals within these areas shall comply with the following requirements:

a. Meet all applicable provisions of this title;

b. Meet all applicable provisions of the International Building Code with regard to wall and footing setbacks for slopes, grading, drainage and compaction of fills;

c. Provide an engineering study, prepared by a professional civil engineer licensed to practice in the state, which includes a hydraulic analysis, a historical and geological evaluation of potential erosion hazards, and an analysis of long-term channel degradation, movement and bank erosion. The study shall also include recommendations for erosion protection measures, if any. The study shall include the engineer’s professional opinion that when the erosion protection measures, if any, are implemented, the proposed development will not be adversely affected by erosion and that the erosion protection measures, if any, will not adversely affect reaches or development upstream, downstream, and across river over a one hundred (100) year planning period;

d. Provide for the perpetual maintenance of the erosion protection, at no cost to the city or other public agency;

e. Provide a maintenance and access easement to any erosion protection. Access to erosion protection shall be located and constructed to minimize flood damage;

f. Obtain necessary section (404) permit from the United States Army Corps of Engineers, and stream alteration permits from the office of the Utah State Engineer prior to any construction activity at no cost to the city; and

g. Hold the city harmless from all claims resulting from erosion or any other flood-related damage to development within an “erosion hazard area” by executing a “flood and erosion hazard disclaimer of liability and agreement” and by placing a “notice of hazard” on the final plat if applicable;

2. All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage;

3. All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage by providing drainage through each lot, unless joint drainage facilities are owned and maintained by an owners’ association; and

4. Base flood elevation data shall be provided for subdivision proposals and other proposed developments which contain at least fifty (50) lots or five (5) acres (whichever is less), or as may be otherwise required by the city engineer or designee.

1. Nonresidential Construction: New construction and substantial improvements of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to one foot (1') above the level of the base flood elevation, or together with attendant utility and sanitary facilities, shall:

a. Be floodproofed so that below the base flood level the structure is watertight from the passage of water;

b. Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;

c. Be certified by a registered professional engineer that the standards of this subsection are satisfied;

d. Require within an AO and AH zone on the FIRM that all new construction and substantial improvements of nonresidential structures:

(1) Have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as the depth number specified in feet on the FIRM (at least two feet (2') if no depth number is specified), or

(2) Together with attendant utility and sanitary facilities be completely floodproofed to that level to meet the floodproofing standard specified in this subsection F1 of this section; and

e. Require within zones AO and AH adequate drainage paths around structures on slopes to guide flood waters around and away from proposed structures;

a. New construction and substantial improvement of any residential structure shall have the lowest floor (including basement) elevated to two feet (2') or more above the base flood elevation;

b. Require within any AO and AH zone on the FIRM that all new construction and substantial improvements of residential structures have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as the depth number specified in feet on the FIRM (at least two feet (2') if no depth number is specified);

c. Require within zones AO and AH adequate drainage paths around structures on slopes to guide flood waters around and away from proposed structures;

d. Require within an A zone on the FIRM that all new construction and substantial improvements of residential structures have the lowest floor (including basements) elevated at least one foot (1') above the highest adjacent grades; and

e. Require within zone A on the FIRM adequate drainage paths around structures on slopes to guide flood waters around and away from proposed structures;

a. Manufactured homes shall be anchored in accordance with subsection B of this section;

b. All manufactured homes or those to be substantially improved shall conform to the following requirements:

(1) Manufactured homes that are placed or substantially improved on a site:

(A) Outside of a manufactured home park or subdivision,

(B) In a new manufactured home park or subdivision,

(D) In an existing manufactured home park or subdivision on which a manufactured home has incurred “substantial damage” as the result of a flood,

Shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated to one foot (1') above the level of the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement, and

(2) Manufactured homes to be placed or substantially improved on sites in existing manufactured home parks or subdivisions that are not subject to the provisions in subsection F1 of this section shall be elevated so that either the lowest floor of the manufactured home is at or above the base flood elevation, or the manufactured home chassis is supported by reinforced piers or other foundation elements that are no less than thirty-six inches (36") in height above grade and shall be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement;

4. Recreational Vehicles: Recreational vehicles shall either:

a. Be on the site for fewer than one hundred eighty (180) consecutive days;

b. Be fully licensed and ready for highway use; or

c. Meet the permit requirements, elevation, and anchoring requirements for resisting wind forces that are applicable to manufactured homes. (Ord. 2019-10-002, 10-10-2019)