Chapter 17B.52D
FLOOD HAZARD AREAS
Sections:
17B.52D.015 Applicability of provisions.
17B.52D.020 Flood hazard regulations.
17B.52D.030 Flood insurance rate maps.
17B.52D.040 Designation of frequently flooded areas.
17B.52D.050 Reporting requirements.
17B.52D.060 Warning and disclaimer of liability.
17B.52D.070 Development standards—Frequently flooded areas.
17B.52D.080 Subdivision of land—Frequently flooded areas.
17B.52D.090 Alteration of watercourses.
17B.52D.010 Purpose.
The purpose of this chapter is to designate and protect flood hazard areas in the downtown waterfront area and shoreline area to protect aquifers used for potable water. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)
17B.52D.015 Applicability of provisions.
Regulations only apply to the Lighthouse Park, Front Street, and Park Street between the shoreline and 1st Street. These regulations do not apply to the various streams and ravines throughout the city because:
A. There are no streams which have a flow of twenty cfs or greater; and
B. The BNSF railroad tracks have effectively bermed the marine shoreline and eliminated flooding problems along the Mukilteo shoreline. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)
17B.52D.020 Flood hazard regulations.
All development proposals in special flood hazard areas shall be subject to the provisions of Chapter 15.12, Flood Damage Prevention. All studies shall be prepared by a registered professional engineer licensed in the state of Washington. At the city’s option, the studies/plans may be reviewed by a consultant retained by the city at the applicant’s expense. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)
17B.52D.030 Flood insurance rate maps.
Flood insurance rate maps (FIRM), the official maps on which the Federal Insurance Administration has delineated both areas of flood hazard and risk premium zones applicable to the community, are available at the city for viewing. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)
17B.52D.040 Designation of frequently flooded areas.
A. Frequently Flooded Areas. Frequently flooded areas shall include:
1. FEMA Maps. Those areas identified on FEMA flood insurance maps as areas of special flood hazard which include those lands in the floodplain subject to a one percent or greater chance of flooding in any given year. For the purposes of this chapter, areas of special flood hazard for the city of Mukilteo are hereby declared generally to be those areas shown as Zone A (including Zones A, AE, A1—A30, AH, AO, AR and A99) on the following FEMA maps or panels: Panel 1010—53061C1010 E, Panel 1020—53061C1020 E, and Panel 1015—53061C1015E. The preceding maps and panels were revised and effective on November 8, 1999, and such maps and panels are adopted by this reference as a part of this chapter as if fully set forth herein or the most recent updates to those maps and panels. In 2010, FEMA began a study of seventy-four miles of coastline in Snohomish County, including Mukilteo, and provided preliminary digital flood insurance rate maps (DFIRM) and studies to Snohomish County, which can be viewed at Snohomish County planning and development services. The urban waterfront and urban waterfront park areas of the shoreline are mapped as high risk flood hazard areas. The urban conservancy areas of the shoreline are also mapped as high risk flood hazard areas, with the area south of Big Gulch Creek having an additional hazard associated with storm waves.
2. City Discretion and Designation. Flood insurance maps, digital flood insurance rate maps (DFIRM), and the city’s critical areas map are to be used as a guide and should be considered a minimum designation of frequently flooded areas. As flood insurance maps may be continuously updated as areas are reexamined or new areas are identified, newer and more restrictive information for flood hazard area identification shall be the basis for regulation. The city of Mukilteo shall retain the right to designate and identify areas known to be prone to flooding outside of the one-hundred-year floodplain and subject them to the provisions and protections of this title and Chapter 15.12.
3. Use of Additional Information. The planning director may use additional flood information that is more restrictive or detailed than that provided in the flood insurance study conducted by the Federal Emergency Management Agency (FEMA) to designate frequently flooded areas, including historical data, high water marks, photographs of past flooding, location of restrictive floodways, maps showing future build-out conditions, maps that show riparian habitat area, or similar information. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)
17B.52D.050 Reporting requirements.
Critical area reports for frequently flooded areas must meet the requirements of this section and Chapter 15.12. Critical area reports for two or more types of critical areas must meet the report requirements for each relevant type of critical area.
A. Preparation by a Qualified Professional. A frequently flooded areas report shall be prepared by a qualified professional who is a hydrologist or engineer licensed in the state of Washington with experience in preparing flood hazard and tsunami assessments.
B. Areas to Be Addressed. The following areas shall be addressed in a critical area report for frequently flooded areas:
1. The site area of the proposed activity;
2. All areas of a special flood hazard area, as indicated on the flood insurance map(s) within two hundred feet of the project area; and
3. All other flood areas indicated on the flood insurance map(s) within two hundred feet of the project area.
C. Flood Hazard Assessment. A critical area report for a proposed activity within a frequently flooded area shall contain a flood hazard and tsunami assessment including the following site and proposal related information at a minimum:
1. Site and Construction Plans. A copy of the site and construction plans for the development proposal showing:
a. Floodplain (one-hundred-year flood elevation), ten- and fifty-year flood elevations, floodway, other critical areas, buffers, and shoreline areas;
b. Proposed development, including the location of existing and proposed structures, fill, storage of materials, drainage facilities, and parking with dimensions indicating distances to the floodplain;
c. Clearing limits; and
d. Elevation of the lowest floor (including basement) of all structures, and the level to which any nonresidential structure has been floodproofed.
2. Watercourse and Floodway Alteration. Alteration of natural watercourses shall be avoided, if feasible. If unavoidable, a critical area report shall include:
a. Extent of Watercourse and Floodway Alteration. A description of and plan showing the extent to which a watercourse and floodway will be altered or relocated as a result of proposal;
b. Maintenance Program Required for Watercourse and Floodway Alterations. A maintenance program that provides maintenance practices for the altered or relocated portion of the watercourse and floodway to ensure that the flood carrying capacity is not diminished;
c. Information Regarding Other Critical Areas. Potential impacts to wetlands, fish and wildlife habitat, shorelines, and other critical areas shall be addressed in accordance with the applicable sections of this title; and
d. Compliance Documentation. Information describing and documenting how the proposed watercourse and floodway alteration complies with the requirements of the fish and wildlife habitat conservation areas chapter of this title, the Mukilteo shoreline management plan, and other applicable state or federal permit requirements. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)
17B.52D.060 Warning and disclaimer of liability.
The degree of flood protection required by this chapter and Chapter 15.12 is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. Larger floods or tsunamis can and will occur on rare occasions. Flood heights may be increased by manmade or natural causes. This title does not imply that land outside frequently flooded areas or uses permitted within such areas will be free from flooding or flood damages. This title shall not create liability on the part of the city of Mukilteo, any officer or employee thereof, or the Federal Insurance Administration for any flood damages that result from reliance on this title or any administrative decision lawfully made hereunder. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)
17B.52D.070 Development standards—Frequently flooded areas.
Development standards and provisions for protection of frequently flooded areas are provided as applicable to areas of special flood hazard in Chapter 15.12. Conformance with the provisions for flood hazard reduction in Chapter 15.12 shall constitute conformance with the protection of critical areas Section 17B.52.010 per the mandates of the Washington Growth Management Act and purposes and objectives of this title. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)
17B.52D.080 Subdivision of land—Frequently flooded areas.
All lots created through binding site plans, subdivision, short subdivisions, or adjusted through lot line adjustments shall provide adequate building space outside the one-hundred-year floodplain, the floodway, and the channel migration and floodway zone. The location of the floodplain, floodway, or channel migration zone shall be shown as a “no-build” zone on the face of the preliminary and final plat, binding site plan, or record of survey in the case of a lot line adjustment. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)
17B.52D.090 Alteration of watercourses.
Alteration of natural watercourses shall be avoided, if feasible. If unavoidable, the following provisions shall apply to the alteration:
A. Habitat Regulations. Watercourse alteration shall only be allowed in accordance with the fish and wildlife habitat conservation areas chapter of this title.
B. Blockage. Watercourse alteration project shall not result in blockage of side channels.
C. Notification. In accordance with city’s noticing requirements contained in Chapter 17B.13, the city shall notify adjacent communities, the State Departments of Ecology and Fish and Wildlife, and the Federal Insurance Administration about the proposed watercourse alteration.
D. Maintenance of Alterations. The applicant shall maintain the altered or relocated portion of the watercourse to ensure that the flood carrying capacity is not diminished. Maintenance shall be bonded for a period of five years, and be in accordance with an approved maintenance program. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)