11-1-5: PROVISIONS FOR FLOOD HAZARD REDUCTION:

   A.   Subdivision Standards: No new subdivisions shall be permitted within a flood hazard area.

   B.   Construction Standards: In the areas of special flood hazard, not lying within a floodway, developments, including fill, new construction and substantial improvements, shall require certification from a registered professional engineer that such developments shall not result in an increase in base flood elevations greater than one foot (1'). The cumulative impacts of such proposed developments when combined with all other existing and anticipated development, will not increase the water surface of the base flood more than one foot (1') at any point within the floodplain of the city of Fruitland. In addition the following provisions are required:

      1.   New construction and substantial improvements of an existing structure, including a structure that has been substantially damaged, shall be anchored to prevent flotation, collapse or lateral movement of the structure.

      2.   New construction and substantial improvements of an existing structure, including a structure that has been substantially damaged, shall be constructed with materials and utility equipment resistant to flood damage.

      3.   New construction or substantial improvements of an existing structure, including a structure that has been substantially damaged, shall be constructed by methods and practices that minimize flood damage.

      4.   All new construction or substantial improvements of an existing structure, including a structure that has been substantially damaged, that includes a fully enclosed area located below the lowest floor formed by the foundation and other exterior walls shall be designed to be an unfinished or flood resistant enclosure. The enclosure shall be designed to equalize hydrostatic flood forces on exterior walls by allowing for the automatic entry and exit of floodwater. Designs for complying with this requirement must be certified by a licensed professional engineer or architect or meet the following minimum criteria:

         a.   Provide a minimum of two (2) openings:

            (1)   With a total net area of not less than one square inch for every square foot of enclosed area subject to flooding;

            (2)   The bottom of all openings shall be no higher than one foot (1') above the higher of the exterior or interior grade or floor immediately below the opening;

            (3)   Openings may be equipped with screens, louvers, valves or other coverings or devices, provided they permit the automatic flow of floodwater in both directions without manual intervention.

         b.   To comply with the "lowest floor" criteria of this chapter, the unfinished or flood resistant enclosure shall only be used for parking of vehicles, limited storage of maintenance equipment used in connection with the premises, or entry to the elevated area.

         c.   The interior portion of such enclosed area shall not be partitioned or finished into separate rooms.

         d.   For crawl space foundation types, construction must follow the guidelines in FEMA TB 11-01, crawl space construction for structures located in special flood hazard areas, national flood insurance program interim guidance, specifically:

            (1)   Below grade crawl spaces are prohibited at sites where the velocity of floodwaters exceed five feet (5') per second;

            (2)   Interior grade of the crawl space below the BFE must not be more than two feet (2') below the lowest adjacent exterior grade (LAG);

            (3)   Height of the below grade crawl space, measured from the lowest interior grade of the crawl space to the bottom of the floor joist must not exceed four feet (4') at any point;

            (4)   Contain an adequate drainage system that removes floodwaters from the interior area of the crawl space.

      5.   All heating and air conditioning equipment and components, all electrical, ventilation, plumbing, and other facilities shall be designed and/or elevated to prevent water from entering or accumulating within the components during flooding.

      6.   New and replacement water supply systems shall be designed to minimize or to eliminate infiltration of floodwaters into the system.

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

      8.   On site waste disposal systems shall be located and constructed to avoid functional impairment, or contamination from them, during flooding.

      9.   Any alteration, repair, reconstruction or improvement to a structure that is not compliant with the provisions of this chapter, shall be undertaken only if the nonconformity is minimal in order to meet health and safety standards.

   C.   Manufactured Home Standards: In all areas of special flood hazard where the flood protection elevation is established, these standards for manufactured homes and recreational vehicles that are an allowed use under the zoning ordinance shall apply:

      1.   Manufactured homes placed or substantially improved:

         a.   On individual lots or parcels.

         b.   In new or substantially improved manufactured home parks or subdivisions.

         c.   In expansions to existing manufactured home parks or subdivisions, or on a site in an existing manufactured home park or subdivision where a manufactured home has incurred "substantial damage" as the result of a flood, must have the lowest floor, including basement, elevated to the flood protection elevation.

      2.   Manufactured homes placed or substantially improved in an existing manufactured home park or subdivision may be elevated so that either:

         a.   The lowest floor of the manufactured home is elevated to the flood protection elevation, or one foot (1') above the level of the base flood elevation, whichever is higher.

         b.   The manufactured home chassis is elevated and supported by reinforced piers (or other foundation elements of at least an equivalent strength) of no less than thirty six inches (36") above the highest adjacent grade.

      3.   Manufactured homes shall be anchored to prevent flotation, collapse or lateral movement. Methods of anchoring may include, but are not limited to, use of over the top or frame ties to ground anchors. This standard shall be in addition to, and consistent with, applicable state requirements.

      4.   Manufactured homes placed on solid perimeter walls shall meet the flood vent requirements in subsection B4 of this section.

   D.   Accessory Structures: Relief from the elevation or dry floodproofing standards may be granted for an accessory structure containing no more than two hundred (200) square feet. Such a structure must meet the following standards:

      1.   It shall not be used for human habitation;

      2.   It shall be constructed of flood resistant materials;

      3.   It shall be constructed and placed on the lot to offer the minimum resistance to the flow of floodwaters;

      4.   It shall be firmly anchored to prevent flotation;

      5.   Services such as electrical and heating equipment shall be elevated or floodproofed to or above the flood protection elevation;

      6.   It shall meet the opening requirements of subsection B4 of this section.

   E.   Recreational Vehicle Standards: In all areas of special flood hazard, recreational vehicles must either:

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

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

      3.   The recreational vehicle must meet all the requirements for "new construction", including the anchoring and elevation requirements.

   F.   Floodway Standards: In areas where the floodway has not been established, the applicant shall be required to establish the data and obtain approval through FEMA prior to filing for a floodplain development permit. The following provisions shall apply in a floodway:

      1.   A project in the regulatory floodway must undergo an encroachment review to determine its effect on flood flows. An encroachment analysis must include:

         a.   Determination and documentation that the filling, grading or construction of a structure will not obstruct flood flows and will not cause an increase in flood heights upstream or adjacent to the project site;

         b.   Determination and documentation that grading, excavation, channel improvements, bridge and culvert replacements that remove an obstruction, do not cause increases in downstream flood flows;

         c.   Certification and documentation by a licensed professional engineer that the project will not result in a rise in flood heights;

         d.   The administrator may make the encroachment determination for minor projects, such as projects that do not increase the natural grade (e.g., paving a driveway or parking lot at existing grade, open fences and small isolated obstructions such as a mailbox or utility pole).

      2.   Upon demonstrating that there are no alternatives, the applicant may propose an encroachment in the floodway that will cause an increase in the base flood elevation in excess of the allowable level; provided, that the applicant obtain a conditional letter of map revision from FEMA before the development can be approved and permitted.

   G.   Standards For Special Flood Hazard Areas: In areas where the BFE or the floodway has not been established, the applicant shall be required to establish the data and obtain approval through FEMA prior to filing for a floodplain development permit.

      1.   In areas designated A1-30, AE, AH, AO and A, the following provisions are required:

         a.   New Residential Construction And Substantial Improvements: Where base flood elevation data are available, new construction or substantial improvement of any residential structure or manufactured home shall have the lowest floor, including basement, constructed at or above the community's flood protection elevation. If solid foundation perimeter walls are used to elevate a structure, openings sufficient to facilitate the unimpeded movement of floodwaters shall be provided in accordance with the construction standards in subsection B4 of this section.

         b.   Nonresidential Construction: New construction or the substantial improvement of any nonresidential structure located in zones A1-30, AE, or AH must be floodproofed if the new construction or improvement is not elevated. The structure and attendant utility and sanitary facilities, must be designed to be watertight to the flood protection elevation or to one foot (1') above the base flood elevation, whichever is higher, with walls substantially impermeable to the passage of water, and structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effect of buoyancy. A licensed professional engineer or architect must certify that the design and methods of construction are in accordance with accepted standards of practice for meeting these provisions, and shall provide certification to the administrator.

         c.   Places Where Floodway Not Determined: Where the floodway has not been determined, no new construction, substantial improvements or other development (including fill) shall be permitted in zones A1-30 and AE on the effective 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. Applicants of proposed projects that increase the base flood elevation more than one foot (1') are required to obtain and submit to the floodplain administrator, a conditional letter of map revision (CLOMR) preconstruction.

         d.   Building Setback: There shall be a building setback of seventy five feet (75') from the floodway line.

         e.   Postconstruction Application: Postconstruction, the applicant must apply to FEMA for a letter of map revision for changes to the flood hazard map proposed in the CLOMR.

         f.   Drainage Paths: In AH and AO zones, drainage paths shall be provided to guide floodwater around and away from proposed and existing structures.

   H.   Alteration Of A Watercourse: A watercourse is considered altered when any change occurs within its banks.

      1.   The bankfull flood carrying capacity of the altered or relocated portion of the watercourse shall not be diminished. Prior to issuance of a floodplain development permit, the applicant must submit a description of the extent to which any watercourse will be altered or relocated as a result of the proposed development and submit certification by a registered professional engineer that the bankfull flood carrying capacity of the watercourse will not be diminished.

      2.   Adjacent communities, the U.S. army corps of engineers and the Idaho department of water resources stream channel alteration program must be notified prior to alteration or relocation of a watercourse. Evidence of notification must be submitted to the floodplain administrator and to the federal emergency management agency.

      3.   The applicant shall be responsible for providing the necessary maintenance for the altered or relocated portion of the watercourse so that the flood carrying capacity will not be diminished.

      4.   The applicant shall meet the requirements to submit technical data in subsection I of this section when an alteration of a watercourse results in the relocation or elimination of the special flood hazard area, including the placement of culverts.

   I.   Requirement To Submit New Technical Data:

      1.   Development Proposals: For all development proposals that impact floodway delineations or base flood elevations, the community shall ensure that technical data reflecting such changes be submitted to FEMA within six (6) months of the date such information becomes available. These development proposals include:

         a.   Floodway encroachments that increase or decrease base flood elevations or alter floodway boundaries;

         b.   Fill sites to be used for the placement of proposed structures where the applicant desires to remove the site from the special flood hazard area;

         c.   Alteration of watercourses that result in a relocation or elimination of the special flood hazard area, including the placement of culverts;

      2.   Submittal In Proper Format; Fees: It is the responsibility of the applicant to have technical data prepared in a format required for a conditional letter of map revision or letter of map revision and submitted to FEMA. Submittal and processing fees for these map revisions shall be the responsibility of the applicant.

      3.   Flood Studies:

         a.   The study shall be performed using the U.S. army corps of engineers hydrologic engineering center's HEC-2, HEC-RAS (river analysis system), or equivalent programs to calculate water surface elevations.

         b.   The study report shall include field survey data and relevant bench marks used as bases of calculations as cross sections, stream profile and plan showing cross section locations.

         c.   The study report shall attach HEC-2, HEC-RAS, or equivalent input and output reports as appendices.

         d.   Any floodway or floodplain modification shall not be effective until approved by FEMA.

         e.   The study shall include a reach of stream extending beyond the property boundaries of the development upstream and downstream not less than twice the average width of floodway on or adjacent to the development property.

   J.   Fill:

      1.   Fill shall be placed using good engineering practices to ensure that it is reasonably safe from flooding. Fill areas may be protected by retaining walls, pursuant to subsection B of this section. The height of retaining walls shall not exceed the height of the fill. Retaining walls shall be constructed of durable or permanent materials, which are attractive earth tone or natural colored material, and screened to blend with the floodplain vegetation. Retaining walls shall be constructed and reinforced according to the preengineered design standards and for the retaining wall system used or, if not preengineered, shall require some reinforcement for walls above two feet (2') in height and, if greater than four feet (4') in height, shall require structural design parameters capable of resisting hydrostatic and hydrodynamic loads and the effect of buoyancy, as certified by a registered professional engineer. Retaining walls may not be built in areas that have not been filled.

   K.   Preexisting Nonconforming Developments: A development that predates the adoption of this chapter, but which is not in conformity with the provisions of this chapter, may be continued, subject to the following conditions:

      1.   No such use or structure shall be expanded, enlarged or altered in any way, which increases its nonconformity unless a variance is approved.

      2.   If any nonconforming use or structure is substantially damaged it shall not be reconstructed except in conformity with the provisions of this chapter.

   L.   Exempt Buildings: The only structures that shall be exempt from the engineering requirements outlined in this chapter are hay barns that meet all of the following standards:

      1.   Are open on all four (4) sides;

      2.   Are placed upon natural grade;

      3.   Are constructed with materials and utility equipment resistant to flood damage;

      4.   Are not proposed to reside within the floodway;

      5.   Are not used for storage of materials that are flammable, noxious, toxic or otherwise injurious to persons or property if transported by floodwaters. (1984 Code § 12-1-5)