The legislature of the state of Idaho has in Idaho Code sections 46-1020 through 46-1024 delegated the responsibility to local governmental units to adopt regulations designed to promote the public health, safety, and general welfare of its citizenry. Therefore, the city of Pocatello does adopt this chapter, including this section, and the following sections. (Ord. 2865 § 1, 2009)

It is the purpose of this chapter to promote the public health, safety, and general welfare, and to minimize public and private losses due to flood conditions in specific areas, by methods and provisions designed for:

A. Restricting or prohibiting uses which are dangerous to health, safety, and property due to water or erosion hazards, or which result in damaging increases in erosion or in flood heights or velocities;

B. Requiring that uses vulnerable to floods, including facilities which serve such uses, be protected against flood damage at the time of initial construction;

C. Controlling filling, grading, dredging, and other development which may increase flood damage; and

D. Preventing and regulating the construction of flood barriers which will unnaturally divert floodwaters or which may increase flood hazards in other areas. (Prior code § 4-10-1)

Unless specifically defined in this section, words and phrases used in this chapter shall be interpreted so as to give them the meaning they have in common usage and to give this chapter its most reasonable application.

APPEAL: A request for a review of the city engineer's interpretation of any provision of the ordinance codified herein or a request for a variance.

AREA OF SHALLOW FLOODING: A designated AO or AH zone on the flood insurance rate map (FIRM). The base flood depths range from one to three feet (3'); a clearly defined channel does not exist; the path of flooding is unpredictable and indeterminate; and, velocity flow may be evident. AO is characterized as sheet flow and AH indicates ponding.

AREA OF SPECIAL FLOOD HAZARD: The land in the floodplain within a community subject to a one percent (1%) or greater chance of flooding in any given year. Designation on maps always includes the letters A or V.

BASE FLOOD: The flood having a one percent (1%) chance of being equaled or exceeded in any given year. Also referred to as the "100-year flood". Designation on maps always includes the letters A or V.

BASEMENT: Any area of the building having its floor subgrade (below ground level) on all sides.

DEVELOPMENT: Any manmade change to improved or unimproved real estate, including, but not limited to, buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations located within the area of special flood hazard.

FLOOD INSURANCE RATE MAP (FIRM): The official map on which the federal insurance administration has delineated both the areas of special flood hazards and the risk premium zones applicable to the community.

FLOOD INSURANCE STUDY: The official report provided by the federal insurance administration that includes flood profiles, the flood boundary floodway map, and the water surface elevation of the base flood.

FLOOD OR FLOODING: A general and temporary condition of partial or complete inundation of normally dry land areas from:

A. The overflow of inland and tidal waters; and/or

B. The unusual and rapid accumulation of runoff of surface waters from any source.

FLOOD PROTECTION ELEVATION (FPE): An elevation that shall correspond to the elevation of the one percent (1%) chance flood (100-year flood) plus any increased flood elevation due to floodway encroachment, plus any required freeboard.

FLOODWAY: The channel of a river or stream and those portions of the floodplain adjoining the channel required to discharge and store the floodwater or flood flows associated with the regulatory flood.

LOWEST FLOOR: The lowest floor of the lowest enclosed area (including basement). An unfinished or flood resistant enclosure, usable solely for parking of vehicles, building access or storage, in an area other than a basement area, is not considered a building's lowest floor; provided, that such enclosure is not built so as to render the structure in violation of the applicable nonelevation design requirements of section 15.32.140 of this chapter.

MANUFACTURED HOME: A structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when connected to the required utilities. For floodplain management purposes, the term "manufactured home" also includes park trailers, travel trailers, and other similar vehicles placed on a site for greater than one hundred eighty (180) consecutive days. For insurance purposes the term "manufactured home" does not include park trailers, travel trailers, and other similar vehicles.

MANUFACTURED HOME PARK OR SUBDIVISION: A parcel (or contiguous parcels) of land divided into two (2) or more manufactured home lots for rent or sale.

NEW CONSTRUCTION: Structures for which the "start of construction" commenced on or after the effective date of the ordinance codified in this chapter.

RECREATIONAL VEHICLE: A vehicle built on a single chassis, consisting of four hundred (400) square feet or less when measured at the largest horizontal projection, designed to be self-propelled or permanently towable by a light duty truck, and designed primarily not for use as a permanent dwelling but as temporary living quarters for recreational, camping, travel, or seasonal use.

REGULATORY FLOOD: A flood determined to be representative of large floods known to have occurred in Idaho and which may be expected to occur on a particular stream because of like physical characteristics. The regulatory flood is based upon a statistical analysis of stream flow records available for the watershed or an analysis of rainfall and runoff characteristics in the watershed. In inland areas, the flood frequency of the regulatory flood is once in every one hundred (100) years; this means that in any given year there is a one percent (1%) chance that a regulatory flood may occur or be exceeded.

START OF CONSTRUCTION: Includes substantial improvement, and means the date the building permit was issued, provided the actual start of construction, repair, reconstruction, placement or other improvement was within one hundred eighty (180) days of the permit date. The "actual start" means either the first placement of permanent construction of a structure on a site, such as the pouring of slab or footings, the installation of tiles, the construction of columns, or any work beyond the stage of excavation or the placement of a manufactured home on a foundation. "Permanent construction" does not include land preparation, such as clearing, grading and filling; nor does it include the installation of streets and/or walkways; nor does it include the installation on the property of accessory buildings, such as garages or sheds not occupied as dwelling units or not part of the main structure. For a substantial improvement, the "actual start of construction" means the first alteration of any wall, ceiling, floor, or other structural part of a building, whether or not that alteration affects the external dimensions of the building.

STRUCTURE: The walled and roofed building including a gas or liquid storage tank that is principally aboveground.

SUBSTANTIAL DAMAGE: Damage of any origin sustained by a structure whereby the cost of restoring the structure to its before damaged condition would equal or exceed fifty percent (50%) of the market value of the structure before the damage occurred. Work on structures that are determined to be substantially damaged is considered to be substantial improvement, regardless of the actual repair work performed.

SUBSTANTIAL IMPROVEMENT: Any repair, reconstruction or improvement of a structure, the cost of which equals or exceeds fifty percent (50%) of the market value of the structure either:

A. Before the improvement or repair is started; or

B. If the structure has been damaged and is being restored, before the damage occurred. For the purposes of this definition, "substantial improvement" is considered to occur when the first alteration of any wall, ceiling, floor, or other structural part of the building commences, whether or not that alteration affects the external dimensions of the structure.

The term does not, however, include either:

A. Any project for improvement of a structure to comply with existing state or local health, sanitary or safety code specifications which are solely necessary to assure safe living conditions;

B. Any alteration of a structure listed in the National Register of Historic Places or a state inventory of historic places.

"Cumulative substantial improvement" shall be defined as any reconstruction, rehabilitation, addition, or other improvement of a structure that equals or exceeds fifty percent (50%) of the market value of the structure at the time of improvement or repair when counted cumulatively for five (5) years.

VARIANCE: A grant of relief from the requirements of the ordinance codified herein which permits construction in a manner that would otherwise be prohibited by the ordinance codified herein. (Ord. 2865 § 2, 2009: Ord. 2237 § 1, 1987)

A. Lands To Which This Chapter Applies: This chapter shall apply to all areas of special flood hazards within the jurisdiction of the city of Pocatello, Idaho.

B. Basis For Establishing The Areas Of Special Flood Hazard: The areas of special flood hazard identified by the federal insurance administration in a scientific and engineering report entitled the "Flood Insurance Study For Bannock County, Idaho And Incorporated Areas" dated July 7, 2009, with accompanying flood insurance rate maps are hereby adopted by reference and declared to be a part of this chapter. The study and maps shall be on file and available in the office of the city engineer. (Ord. 2865 § 3, 2009)

A development permit shall be obtained before construction or development begins within any area of special flood hazard established in subsection 15.32.030B of this chapter. The permit shall be for all structures, including manufactured homes, as set forth in the definitions in section 15.32.020 of this chapter, and for all other development including fill and other activities, also as set forth in section 15.32.020 of this chapter. (Ord. 2237 § 2, 1987: prior code § 4-10-4(A))

The city engineer is appointed to administer and implement this chapter by granting or denying development permit applications in accordance with its provisions. (Ord. 2237 § 3, 1987: 1983 Code: prior code § 4-10-4(B))

The duties of the city engineer shall include, but not be limited to:

A. Permit Review:

1. Review all development permits to determine that the permit requirements of this chapter have been satisfied.

2. Review all development permits to determine that all necessary permits have been obtained from those federal, state, or local governmental agencies from which prior approval is required.

3. Review all development permits to determine if the proposed development is located in the floodway. If located in the floodway, assure that the encroachment provisions of subsection 15.32.170A of this chapter are met.

B. Use Of Other Flood Data: When base flood elevation data has not been provided in accordance with subsection 15.32.030B of this chapter, the city engineer shall obtain, review, and reasonably utilize any base flood elevation and floodway data available from a federal, state or other source, in order to administer subsections 15.32.140A, 15.32.150A and 15.32.170A of this chapter.

C. Information To Be Obtained And Maintained:

1. Where base flood elevation data is provided through the flood insurance study, FIRM, or required as in subsection B of this section, obtain, verify, and record the actual (as built) elevation (in relation to mean sea level) of the lowest floor (including basement) of all new or substantially improved structures, and whether or not the structure contains a basement. (44 CFR 60.3(b)(5)(i).) As built elevation shall be recorded on a current elevation certificate (FF 81-31) with section B completed by the local official.

2. For all new or substantially improved floodproofed nonresidential structures where base flood elevation data is provided through the FIS, FIRM, or as required in subsection B of this section:

a. Obtain, verify and record the actual elevation (in relation to mean sea level) to which the structure was floodproofed (44 CFR 60.3(b)(5)(ii)).

b. Maintain the floodproofing certifications required in section 15.32.150 of this chapter (44 CFR 60.3(b)(5)(iii)).

3. Maintain for public inspection all records pertaining to the provisions of this chapter (44 CFR 60.3(b)(5)(iii)).

D. Alteration Of Watercourses:

1. Notify adjacent communities and the state prior to any alteration or relocation of a watercourse, and submit evidence of such notification to the federal insurance administration;

2. Require that maintenance is provided within the altered or relocated portion of the watercourse so that the flood carrying capacity is not diminished.

E. Interpretation Of FIRM Boundaries: Make interpretations where needed, as to exact location of the boundaries of the areas of special flood hazards, i.e., where there appears to be a conflict between a mapped boundary and actual field conditions. The person contesting the location of the boundary shall be given a reasonable opportunity to appeal the interpretation. Such appeals shall be granted consistent with the standards of section 1910.6 of the rules and regulations of the national flood insurance program (24 CFR 1909, etc.).

F. Penalties For Noncompliance: No structure or land shall hereafter be constructed, located, extended, converted, or altered without full compliance with the terms of this chapter and other applicable regulations. Violations of the provisions of this chapter by failure to comply with any of its requirements (including violations of conditions and safeguards established in connection with conditions), shall constitute a misdemeanor. Any person who violates this chapter or fails to comply with any of its requirements shall upon conviction thereof be subject to the penalties provided for in section 1.04.040 of this code, and in addition shall pay all costs and expenses involved in the case. Nothing herein contained shall prevent the city of Pocatello from taking such other lawful action as is necessary to prevent or remedy any violation.

G. Abrogation And Greater Restrictions: This chapter is not intended to repeal, abrogate, or impair any existing easements, covenants, or deed restrictions. However, where this chapter and another ordinance, easement, covenant, or deed restriction conflict or overlap, whichever imposes the more stringent restrictions shall prevail. (Ord. 2865 § 4, 2009: Ord. 2237 §§ 4_6, 1987: 1983 Code: prior code § 4-10-4(C))

In all areas of special flood hazards, the standards set out in sections 15.32.080 through 15.32.120 of this chapter are required. (Prior code § 4-10-5.1)

A. All new construction and substandard improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure.

B. All manufactured homes must likewise be anchored to prevent flotation, collapse, or lateral movement, and shall be installed using practices and methods that minimize flood damage. Anchoring methods may include, but are not limited to, use of over the top or frame ties to ground anchors. (Reference FEMA's "Manufactured Home Installation In Flood Hazard Areas" guidebook for additional techniques.)

C. An alternative method of anchoring may involve a system designed to withstand wind force of ninety (90) miles per hour or greater. Certification must be provided to the federal insurance administration that this standard has been met. (Ord. 2237 § 7, 1987: prior code § 4-10-5.1(A))

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. Electrical heating, ventilation, plumbing, and air conditioning equipment and other service facilities shall be designed and/or otherwise elevated or located so as to prevent water from entering or accumulating within the components during conditions of flooding. (Ord. 2237 § 8, 1987: prior code § 4-10-5.1(B))

A. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems;

B. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharge from the systems into floodwaters; and

C. On site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding. (Prior code § 4-10-5.1(C))

A. All subdivision proposals shall be consistent with the need to minimize flood damage.

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

C. All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage; and

D. Where base flood elevation data has not been provided or is not available from another authoritative source, it shall be generated for subdivision proposals and other proposed developments which contain fifty (50) lots or five (5) acres (whichever is less). (Ord. 2237 § 9, 1987: prior code § 4-10-5.1(D))

Where elevation data is not available, either through the flood insurance study or from another authoritative source, as set forth in subsection 15.32.060B of this chapter, applications for building permits shall be reviewed to assure that proposed construction will be reasonably safe from flooding. The test of reasonableness is a local judgment and includes use of historical data, high water marks, photographs of past flooding, etc., where available. Failure to elevate at least two feet (2') above grade in these zones may result in higher insurance rates. (Ord. 2237 § 10, 1987: prior code § 4-10-5.1(E))

In all areas of special flood hazards where base flood elevation data has been provided as set forth in subsections 15.32.030B and 15.32.060B of this chapter, the provisions of sections 15.32.140 through 15.32.160 of this chapter are required. (Prior code § 4-10-5.2)

A. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to or above the flood protection elevation (FPE).

B. Fully enclosed areas below the lowest floor that are subject to flooding are prohibited, or shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or must meet or exceed the following minimum criteria:

1. A minimum of two (2) 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;

2. The bottom of all openings shall be no higher than one foot (1') above grade;

3. Openings may be equipped with screens, louvers, or other coverings or devices; provided, that they permit the automatic entry and exit of floodwaters; and

4. The area subject to flooding must meet or exceed the criteria contained in the federal emergency management agency (FEMA) technical bulletin 11-01, which bulletin is hereby adopted and incorporated into this section by reference. A copy of FEMA technical bulletin 11-01 is available for inspection and copying upon request made to the city engineer. (Ord. 2865 § 5, 2009: Ord. 2847 § 1, 2008: Ord. 2237 § 11, 1987)

New construction and substantial improvement of any commercial, industrial, or other nonresidential structure shall either have the lowest floor, including basement, elevated to the level of the flood protection elevation (FPE); or, together with attendant utility and sanitary facilities, shall:

A. Be floodproofed so that below the flood protection elevation (FPE) of the structure is watertight with walls substantially impermeable to the passage of water;

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

C. Be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting provisions of this section based on their development and/or review of the structural design, specifications and plans. Such certification shall be provided to the official as set forth in subsection 15.32.080C of this chapter.

D. Nonresidential structures that are elevated, not floodproofed, must meet the same standards for space below the lowest floor as described in subsection 15.32.140B of this chapter.

E. Applicants for floodproofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one foot (1') below the floodproofed level (e.g., a building constructed to the base flood level will be rated as 1 foot below that level). (Ord. 2865 § 6, 2009: Ord. 2237 §§ 12, 13, 1987: prior code § 4-10-5.2(B))

All manufactured homes to be placed or substantially improved within zones A1-30, AH, and AE shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is at or above the flood protection elevation (FPE) and be securely anchored to an adequately anchored foundation system in accordance with the provisions of subsection 15.32.080B of this chapter. (Ord. 2865 § 7, 2009)

Recreational vehicles placed on sites are required to either:

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

B. Be fully licensed and ready for highway use, on wheels or jacking system, attached to the site only by quick disconnect type utilities and security devices, and have no permanently attached additions; or

C. Meet the requirements of section 15.32.160 of this chapter and the elevation and anchoring requirements for manufactured homes. (Ord. 2865 § 8, 2009)

In areas with base flood elevations (but a regulatory floodway has not been designated), no new construction, substantial improvements, or other development (including fill) shall be permitted within zones A1-30 and AE on the community's FIRM, unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot (1') at any point within the community. (Ord. 2865 § 9, 2009)

Located within areas of special flood hazard established in subsection 15.32.030B of this chapter 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:

A. Prohibit encroachments, including fill, new construction, substantial improvements, and other development unless a no rise certification by a registered professional engineer is provided demonstrating that encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge;

B. If subsection A of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of sections 15.32.070 through 15.32.180 of this chapter;

C. Prohibit the placement of any manufactured homes, except in an existing manufactured home park or existing manufactured home subdivision. (Ord. 2865 § 10, 2009: Ord. 2237 § 15, 1987: prior code § 4-10-5.3)

Shallow flooding areas appear on FIRMs as AO zones with depth designations. The base flood depths in these zones range from one to three feet (3') where a clearly defined channel does not exist, or where the path of flooding is unpredictable and where velocity flow may be evident. Such flooding is usually characterized as sheet flow. In these areas, the following provisions apply:

A. New construction and substantial improvements of residential structures within AO zones shall have the lowest floor (including basement) elevated above the highest adjacent grade of the building site, to or above the flood protection elevation (FPE) (at least 2 feet if no depth number is specified on the FIRM).

B. New construction and substantial improvement of nonresidential structures within AO zones shall either:

1. Have the lowest floor (including basement) elevated above the highest adjacent grade of the building site, to or above the flood protection elevation (FPE) (at least 2 feet if no depth number is specified on the FIRM); or

2. Together with attendant utility and sanitary facilities, be completely floodproofed to or above that level so that any space below that level 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. If this method is used, compliance shall be certified by a registered professional engineer or architect as in subsection 15.32.150C of this chapter.

C. Require adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures. (Ord. 2865 § 11, 2009: Ord. 2237 § 16, 1987)

In order to secure a variance from the requirements of this chapter in order to secure a building permit, an applicant for such a permit may follow the variance procedures set forth in 44 CFR 60.6(a)(1-7), criteria for land management and use, variances and exceptions, three (3) copies of which are on file in the office of the city engineer, which regulations are adopted by reference, and declared to be part of this chapter. (Ord. 2865 § 12, 2009)

The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. Larger floods can and will occur on rare occasions. Flood heights may be increased by manmade or natural causes. This chapter does not imply that land outside the areas of special flood hazards or uses permitted within such areas will be free from flooding or flood damages. This chapter shall not create liability on the part of the city, any officer or employee thereof, or the federal insurance administration, for any flood damages that result from reliance on this chapter or any administrative decision lawfully made thereunder. (Prior code § 4-10-7)