(a) To protect human life and health;

(b) To minimize expenditure of public money and costly flood control projects;

(c) To minimize the need for rescue and relief efforts associated with flooding and generally undertaken at the expense of the general public;

(d) To minimize prolonged business interruptions;

(e) To minimize damage to public facilities and utilities such as water and gas mains, electric, telephone, and sewer lines, streets, and bridges located in flood hazard areas;

(f) To help maintain a stable tax base by providing for the sound use and development of flood hazard areas so as to minimize future flood blight areas;

(g) To ensure that potential buyers are notified that property is in a flood hazard area; and

(h) To ensure that those who occupy the flood hazard areas assume responsibility for their actions.

(a) Restricting or prohibiting uses that 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 the alteration of natural floodplains, stream channels, and natural protective barriers, which help accommodate or channel flood waters;

(d) Controlling filling, grading, dredging, and other development which may increase flood damage; and

(e) Preventing or regulating the construction of flood barriers which will unnaturally divert flood waters or may increase flood hazards in other areas. [Ord. 933 § 9.1, 2019.]

(a) Considered as minimum requirements;

(b) Liberally construed in favor of the governing body; and

(c) Deemed neither to limit nor repeal any other powers granted under state law.

(a) Elevation in relation to mean sea level of the lowest floor (including basement) of all structures;

(b) Elevation in relation to mean sea level to which any structure has been floodproofed;

(c) Certification by a registered professional engineer or architect that the floodproofing methods for any nonresidential structure meets the floodproofing criteria in MDC 18.45.040(9); and

(d) Description of the extent to which a watercourse will be altered or relocated as a result of proposed development.

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

(b) 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.

(c) 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 MDC 18.45.040(13) are met.

(a) Information to be Determined and Maintained.

(b) Alteration of Watercourses. As part of a development permit application, the Community Development Director shall:

(c) Interpretation of FIRM Boundaries. The Community Development Director shall make interpretations, where needed, as to exact location of the boundaries of the flood hazard areas (for example, 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 60.6 of the rules and regulations of the National Flood Insurance Program (44 CFR 59-76). [Ord. 933 § 9.3, 2019.]

(a) All new construction and substantial improvements shall be anchored to prevent flotation, collapse, or lateral movement of the structure.

(b) All manufactured homes must be installed using methods and practices 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).

(a) All new construction and substantial improvements shall be anchored to prevent flotation, collapse, or lateral movement of the structure.

(b) All manufactured homes must be installed using methods and practices that minimize flood damage. Anchoring methods may include, but are not limited to, use of over-the-top or frame ties to ground anchors (see FEMA’s Manufactured Home Installation in Flood Hazard Areas guidebook for additional techniques).

(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.

(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.

(c) On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

(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.

(a) New construction and substantial improvement of any residential structure shall have the lowest floor, including the basement, elevated to one foot above base flood elevation.

(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:

(a) Be floodproofed so that below the base flood level 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.

(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 subsection based on their development and/or review of the structural design, specifications and plans. Such certifications will be provided to the official as set forth in MDC 18.45.030(6)(a)(ii).

(d) Nonresidential structures that are elevated, but not floodproofed, must meet the same standards for space below the lowest floor as described in subsection (8)(b) of this section.

(e) Applicants floodproofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one foot below the floodproofed level (e.g., a building construction to the base flood level will be rated as one foot below the level).

(a) All manufactured homes to be placed or substantially improved within zones A1-A30, and AE on the community’s FIRM on sites:

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

(c) Be placed or substantially improved on sites in an existing manufactured home park or subdivision within Zones A1-A30, and AE on the community’s FIRM, that are not subject to the above manufactured home provisions, be elevated so that either:

(a) The building must be designed and adequately anchored to resist flotation, collapse, and lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy. Hydrostatic loads and the effects of buoyancy can usually be addressed through the required openings discussed in subsection (11)(b). Because of hydrodynamic loads, crawlspace construction is not recommended in areas with flood velocities greater than five feet per second unless the design is reviewed by a qualified design professional, such as a registered architect or professional engineer. Contact the Building Official for recommendations of other types of foundations for these areas.

(b) The crawlspace is an enclosed area below the base flood elevation and, as such, must have openings that equalize hydrostatic pressures by allowing for the automatic entry and exit of floodwaters. The bottom of each flood vent opening can be no more than one foot above the lowest adjacent exterior grade.

(c) Any building utility systems within the crawlspace must be elevated above the base flood elevation or designed so that floodwaters cannot enter or accumulate within system components during flood conditions. Ductwork must be placed above the base flood elevation or sealed to prevent the entry of floodwaters.

(d) Portions of the building below the base flood elevation must be constructed with materials resistant to flood damage. This includes not only the foundation walls of the crawlspace used to elevate the building, but also any joists, insulation, or other materials that extend below the base flood elevation.

(e) The interior grade of a crawlspace below the base flood elevation must not be more than two feet below the lowest adjacent exterior grade.

(f) The height of the below-grade crawlspace, measured from the interior grade of the crawlspace to the top of the crawlspace foundation wall, must not exceed four feet at any point.

(g) There must be an adequate drainage system that removes floodwaters from the interior area of the crawlspace. The enclosed area should be drained within a reasonable time after a flood event. The type of drainage system will vary because of the site gradient and other drainage characteristics, such as soil types.

(h) The velocity of floodwaters at the site should not exceed five feet per second for any crawlspace. For velocities in excess of five feet per second, other foundation types should be used as directed by the Building Official.

(i) Below-grade crawlspace construction in accordance with the requirements listed above will not be considered basements.

(j) Buildings located in areas subject to ponding or low-velocity flows must primarily address issues related to hydrostatic loads on the crawlspace foundation, removal of floodwater and sediment from the crawlspace area, and other National Flood Insurance Program floodproofing requirements, such as protecting or elevating utilities and using flood-resistant materials.

(k) Crawlspace construction is not recommended in zones with high-velocity floodwaters (greater than five feet per second). Other types of foundations, such as open pile or column foundations that allow floodwaters to flow freely beneath the building are recommended for these areas.

(l) Utilities, Access, and Ventilation Openings. Utility systems 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.

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

(b) 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 additions; or

(c) Meet the requirements of subsection (10) of this section and the elevation and anchoring requirements for manufactured homes.

(a) Willow Creek Main Channel. Located within flood hazard areas are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of flood waters which carry debris, potential projectiles, and erosion potential, the following provisions apply:

(b) Willow Creek Overflow.