2. Floodplains shall include, at a minimum, the 100-year floodplain designations of the Federal Emergency Management Agency and the National Flood Insurance Program.

1. Developments in a designated floodway;

2. Developments that result in watercourse alteration; and

3. Developments located adjacent to other critical areas as defined in Chapter 14.255 SMC.

1. To the extent possible consistent with the development objective, all improvements shall be located on the non-floodplain portion of the site, if any, or on the highest ground on the site, as far as possible from the flood source.

2. Alteration of natural watercourses, including side channels, tributaries, and channel migration zones, is to be avoided when feasible. If unavoidable, the Floodplain Administrator shall notify adjacent communities, the Department of Ecology, the State Department of Fish and Wildlife, and FEMA prior to alteration. Any stream-bank stabilization shall consider the use of soft armoring or best available armoring science. (Ord. 2400, 2020)

1. Considered as minimum requirements;

2. Liberally construed in favor of the governing body; and

3. Deemed neither to limit nor repeal any other powers granted under state statutes.

1. Proposed elevation in relation to mean sea level, of the lowest floor (including basement) of all structures recorded on a current elevation certificate with Section B completed by the Floodplain Administrator;

2. Proposed elevation in relation to mean sea level to which any nonresidential structure will be flood proofed;

3. Where a structure is to be flood proofed, certification by a registered professional engineer or architect that the flood proofing methods for any nonresidential structure will meet flood proofing criteria in SMC 14.270.080(B);

4. Description of the extent to which a watercourse will be altered or relocated as a result of proposed development;

5. Where development is proposed in a floodway, an engineering analysis indicating that there will be no rise of the base flood elevation (BFE); and

6. Any other such information that may be reasonably required by the Floodplain Administrator in order to review the application.

1. The permit requirements of this chapter have been satisfied;

2. All other required state and federal permits have been obtained;

3. The site is reasonably safe from flooding; and

4. The proposed development is not located in the floodway, or if located in the floodway, assure the encroachment provisions of SMC 14.270.080(H)(1) are met.

1. Where base flood elevation data is provided through the FIS, FIRM, or as required in subsection F of this section, the Floodplain Administrator shall obtain and maintain 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)).

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

3. Certification required by SMC 14.270.080(H)(1).

4. Records of all variance actions, including justification for their issuance.

5. Improvement and damage calculations.

6. All records pertaining to the provisions of this chapter (44 CFR 60.3(b)(5)(iii)).

1. Notify adjacent communities and the Department of Ecology prior to such alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Insurance Administrator through appropriate notification means (44 CFR 60.3(b)(6));

2. Assure that the flood carrying capacity of the altered or relocated portion of said watercourse is maintained (44 CFR 60.3(b)(7));

3. Base flood elevations may increase or decrease resulting from physical changes affecting flooding conditions. As soon as practicable, but not later than six (6) months after the date such information becomes available, the Floodplain Administrator shall notify the Federal Insurance Administrator of the changes by submitting technical or scientific data in accordance with 44 CFR 65.3. Such a submission is necessary so that upon confirmation of those physical changes affecting flooding conditions, risk premium rates and floodplain management requirements will be based upon current data; and

4. Notify the Federal Insurance Administrator in writing of acquisition by means of annexation, incorporation or otherwise, of additional areas of jurisdiction.

1. If a project will alter the BFE or boundaries of the SFHA, then the project proponent shall provide the Floodplain Administrator with engineering documentation and analysis regarding the proposed change. If the change to the BFE or boundaries of the SFHA would normally require a Letter of Map Change, then the project proponent shall initiate, and receive approval of, a Conditional Letter of Map Revision (CLOMR) prior to approval of the development permit. The project shall be constructed in a manner consistent with the approved CLOMR.

2. If a CLOMR application is made, then the project proponent shall also supply the full CLOMR documentation package to the Floodplain Administrator to be attached to the floodplain development permit, including all required property owner notifications.

1. All development permit applications shall include submittal of a habit assessment done by a qualified professional that includes a full habitat impact analysis of potential effects on Endangered Species Act-listed species and on their critical habitats as required by the NFIP/ESA Biological Opinion dated September 22, 2008, in order to ensure full protection of the critical habitat of ESA-listed salmonids in the flood hazard area.

2. The Floodplain Administrator may waive or modify the requirement to submit a habitat assessment if the proposed project, in its entirety, is for one (1) of the following activities:

1. All new construction and substantial improvements, including those related to manufactured homes, shall be anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads including the effects of buoyancy (44 CFR 60.3(a)(3)(i)).

2. All manufactured homes shall be anchored to prevent flotation, collapse, or lateral movement, and shall 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 (44 CFR 60.3(b)(8)). For more detailed information, refer to guidebook, FEMA-85, “Manufactured Home Installation in Flood Hazard Areas.”

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

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

3. 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.

1. The storage or processing of materials that could be injurious to human, animal, or plant life if released due to damage from flooding is prohibited in special flood hazard areas.

2. Storage of other material or equipment may be allowed if not subject to damage by floods and if firmly anchored to prevent flotation, or if readily removable from the area within the time available after flood warning.

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

2. Water wells shall be located on high ground that is not in the floodway (WAC 173-160-171);

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

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

1. Be consistent with the need to minimize flood damage;

2. Have public utilities and facilities, such as sewer, gas, electrical, and water systems, located and constructed to minimize or eliminate flood damage;

3. Have adequate drainage provided to reduce exposure to flood damage;

4. Where subdivision proposals and other proposed developments contain greater than fifty (50) lots or five (5) acres (whichever is the lesser) base flood elevation data shall be included as part of the application. (Ord. 2400, 2020)

1. In AE or other A zoned areas where the BFE has been determined or can be reasonably obtained, new construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated one foot or more above the BFE. Mechanical equipment and utilities shall be waterproof or elevated at least one foot above the BFE.

2. New construction and substantial improvement of any residential structure in an unnumbered A zone for which a BFE is not available and cannot be reasonably obtained shall be reasonably safe from flooding, but in all cases the lowest floor shall be at least two feet above the highest adjacent grade.

3. Fully enclosed areas below the lowest floor that are subject to flooding are prohibited, or if usable solely for parking, access, or storage, shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs must meet or exceed all of the following minimum criteria:

1. New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall meet all of the following requirements:

2. If the requirements of subsection (B)(1) of this section are not met, then new construction and substantial improvement of any commercial, industrial or other nonresidential structure shall meet all of the following requirements:

3. Applicants who are floodproofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one foot below the floodproofed level and that floodproofing the building an additional foot will reduce insurance premiums significantly.

1. Be on the site for fewer than 180 days; or

2. 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

3. Meet the requirements of subsection C of this section.

1. Accessory structures used solely for parking of vehicles or limited storage may be constructed such that the floor is below the BFE, provided the structure is designed and constructed in accordance with all of the following requirements:

2. Detached garages, storage structures, and other accessory structures not meeting the above standards must be constructed in accordance with all applicable standards in subsection A of this section.

3. Upon completion of the structure, certification that the requirements of this section have been satisfied shall be provided to the Floodplain Administrator for verification.

1. No Rise Standard. Encroachments, including fill, new construction, substantial improvements, and other development in the floodway are prohibited unless certification by a registered professional engineer is provided demonstrating through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachment would not result in any increase in flood levels during the occurrence of the base flood discharge (44 CFR 60.3(d)(3)).

2. Residential Construction in Floodways. Construction or reconstruction of residential structures and mixed use structures with residential dwelling units is prohibited within designated floodways, except for:

3. Replacement of Farmhouses in Floodway. Repairs, reconstruction, replacement, or improvements to existing farmhouse structures located in designated floodways and that are located on lands designated as agricultural lands of long-term commercial significance under RCW 36.70A.170 may be permitted if all of the following requirements are met:

4. Substantially Damaged Residences in Floodway.

5. All Other Building Standards Apply in the Floodway. If subsection (H)(1) of this section is satisfied or construction is allowed pursuant to subsection (H)(2) of this section, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of SMC 14.270.070. (Ord. 2400, 2020; Ord. 2533, 2025)

1. Upon a determination that the granting of a variance will not result in increased flood heights, additional threats to public safety, extraordinary public expense, create nuisances, cause fraud on or victimization of the public, or conflict with existing local laws or ordinances;

2. For the repair, rehabilitation, or restoration of historic structures, upon a determination that the proposed repair or rehabilitation will not preclude the structure’s continued designation as a historic structure and the variance is the minimum necessary to preserve the historic character and design of the structure;

3. Upon a determination that the variance is the minimum necessary, considering the flood hazard, to afford relief;

4. Upon a showing of good and sufficient cause;

5. Upon a determination that failure to grant the variance would result in exceptional hardship to the applicant provided that hardship was not created by the applicant; and

6. Upon a showing that the use cannot perform its intended purpose unless it is located or carried out in close proximity to water. This includes only facilities defined as a “functionally dependent use” in Chapter 14.25 SMC.

1. Any applicant to whom a variance is granted shall be given written notice over the signature of a City of Snohomish official that:

2. The Floodplain Administrator shall maintain a record of all variance actions, including justification for their issuance.

3. The Floodplain Administrator shall condition the variance as needed to ensure that the requirements and criteria of this chapter are met. (Ord. 2400, 2020)