Chapter 15.30
Environmentally Sensitive Areas

Sections:

15.30.010 Purpose

15.30.020 Applicability

15.30.030 Appeals

15.30.040 Sensitive Area Rules

15.30.050 Complete Exemptions

15.30.060 Partial Exemptions

15.30.070 Exceptions

15.30.080 Sensitive Area Maps and Inventories

15.30.090 Disclosure by Applicant

15.30.100 Sensitive Area Review

15.30.110 Sensitive Area Special Study Requirement

15.30.120 Contents of Sensitive Area Special Study

15.30.130 Mitigation, Maintenance, Monitoring and Contingency

15.30.140 Bonds to Insure Mitigation, Maintenance and Monitoring

15.30.150 Vegetation Management Plan

15.30.160 Sensitive Area Markers and Signs

15.30.170 Notice on Title

15.30.180 Sensitive Area Tracts and Designation on Site Plans

15.30.190 Building Setbacks

15.30.200 Erosion Hazard Areas – Development Standards and Permitted Alterations

15.30.210 Flood Hazard Areas – Components

15.30.220 Flood Fringe – Development Standards and Permitted Alterations

15.30.230 Zero-Rise Floodway – Development Standards and Permitted Alterations

15.30.240 FEMA Floodway – Development Standards and Permitted Alterations

15.30.250 Flood Hazard Areas – Certification by an Engineer or Surveyor

15.30.260 Landslide Hazard Areas – Development Standards and Permitted Alterations

15.30.270 Seismic Hazard Areas – Development Standards and Permitted Alterations

15.30.280 Steep Slope Hazard Areas – Development Standards and Permitted Alterations

15.30.290 Wetlands – Development Standards

15.30.300 Wetlands – Permitted Alterations

15.30.310 Wetlands – Alteration of Wetlands Historically and Continuously Used for Agricultural Purposes

15.30.320 Wetlands – Mitigation Requirements

15.30.330 Wetlands – Limited Exemption

15.30.340 Streams – Development Standards

15.30.350 Streams – Permitted Alterations

15.30.360 Streams – Mitigation Requirements

15.30.370 Critical Recharging Areas for Aquifers Used for Potable Water

15.30.380 Fish and Wildlife Habitat Conservation Areas

15.30.010 Purpose

The purpose of this chapter is to implement the goals and policies of the Washington State Environmental Policy Act, Chapter 43.21C RCW, and the SeaTac Comprehensive Plan which call for protection of the natural environment and the public health and safety by:

A.  Establishing development standards to protect defined sensitive areas;

B.  Protecting members of the public, public resources and facilities from injury, loss of life, property damage or financial loss due to flooding, erosion, landslides, seismic and soil subsidence or steep slope failures;

C.  Protecting unique, fragile and valuable elements of the environment including, but not limited to, wildlife and its habitat;

D.  Requiring mitigation of unavoidable impacts on environmentally sensitive areas by regulating alterations in or near sensitive areas;

E.  Preventing cumulative adverse environmental impacts on water availability, water quality, wetlands and streams;

F.  Measuring the quantity and quality of wetland and stream resources and preventing overall net loss of wetland and stream functions;

G.  Protecting the public trust as to navigable waters and aquatic resources;

H.  Meeting the requirements of the National Flood Insurance Program and maintaining SeaTac as an eligible community for federal flood insurance benefits;

I.  Alerting members of the public including, but not limited to, appraisers, owners, real estate agents, potential buyers or lessees to the development limitations of sensitive areas; and

J.  Providing City officials with sufficient information to protect sensitive areas. (Ord. 92-1041 § 1)

15.30.020 Applicability

A.  The provisions of this chapter shall apply to all land uses in the City and property owners within the City shall comply with the requirements of this chapter;

B.  The City shall not approve any permit or issue any authorization to alter the condition of any land, water or vegetation or to construct any structure or improvement without first assuring compliance with the requirements of this chapter; and

C.  When any provision of any other chapter of the SeaTac Municipal Code conflicts with this chapter or when the provisions of this chapter are in conflict, that provision which provides more protection to environmentally sensitive areas shall apply unless specifically provided otherwise in this chapter or unless such provision conflicts with federal or state laws or regulations. (Ord. 92-1041 § 1)

15.30.030 Appeals

Any decision to approve, condition or deny a development proposal based on the requirements of Chapter 15.30 SMC may be appealed according to, and as part of, the appeal procedure for the permit or approval involved. (Ord. 92-1041 § 1)

15.30.040 Sensitive Area Rules

Applicable City departments are authorized to adopt administrative rules and regulations as are necessary and appropriate to implement Chapter 15.30 SMC, and to prepare and require the use of such forms as are necessary for its administration. (Ord. 92-1041 § 1)

15.30.050 Complete Exemptions

The following are exempt from the provisions of this chapter and any administrative rules promulgated thereunder:

A.  Emergencies which threaten the public health, safety and welfare or which pose an imminent risk of damage to private and public property as long as any alteration undertaken pursuant this subsection is reported to the Departments of Planning and Community Development and Public Works immediately, upon which the Director(s) shall either confirm that an emergency exists or determine if further permit review or mitigation is necessary;

B.  Agricultural activities in existence before November 27, 1990 as follows:

1.  Mowing of hay, grass or grain crops;

2.  Tilling, dicing, planting, seeding, harvesting and related activities for pasture, food crops, grass seed or sod if such activities do not take place on steep slopes; and

3.  Normal and routine maintenance of existing irrigation and drainage ditches not used by salmonids;

C.  Public water, electric and natural gas distribution, public and private sewer collection, storm water systems to include retention/detention ponds, cable communications, telephone distribution and collection system, and related activities undertaken pursuant to City approved best management practices, as follows:

1.  Normal and routine maintenance or repair of existing utility structures or rights-of-way;

2.  Relocation of electric facilities, lines, equipment or appurtenances, not including substations, with an associated voltage of fifty-five thousand (55,000) volts or less, only when required by a local governmental agency which approves the new location of facilities;

3.  Replacement, operation, repair, modification or installation or construction in an improved city road right-of-way of all electric facilities, lines, equipment or appurtenances, not including substations, with an associated voltage of fifty-five thousand (55,000) volts or less;

4.  Relocation or maintenance of sanitary and storm sewer systems, public water local distribution, natural gas, cable communication or telephone distribution and collection facilities, lines, pipes, ditches, mains, equipment or appurtenances, only when required by a local governmental agency which approves the new location of the facilities; and

5.  Replacement, operation, repair, modification, installation or construction in an improved City road right-of-way of public local collection, public water distribution, natural gas, cable communication or telephone facilities, lines, pipes, mains, equipment or appurtenances;

D.  Improvements, on-going maintenance, operation, repair or replacement of public roadways and pedestrian improvements in an improved public road right-of-way in existence prior to November 27, 1990 which, at a minimum, is improved with an all-weather driving surface (with any associated shoulders);

E.  Construction and improvements of unimproved public rights-of-way in existence prior to November 27, 1990;

F.  Improvements, on-going maintenance, operation, repair or replacement of public roadways and pedestrian improvements in an improved public road right-of-way constructed after November 27, 1990, in conformance with this chapter which, at a minimum, is improved with an all-weather driving surface (with any associated shoulders);

G.  Emergent wetlands that have been created directly as the result of poorly maintained public storm drainage systems and would have not been created if the storm drainage system had otherwise been maintained;

H.  Public agency development proposals only to the extent of any construction contract awarded before November 27, 1990; provided, that any law or regulation in effect at the time of such award shall apply to the proposal. (Ord. 92-1041 § 1)

15.30.060 Partial Exemptions

The following are exempt from the provisions of this and any administrative rules promulgated thereunder, except for the notice on title provisions, SMC 15.30.170, and the flood hazard area provisions, SMC 15.30.210 through 15.30.250:

A.  Structural modification of, addition to, or replacement of structures, except single-family detached residences, in existence before November 27, 1990, which do not meet the building setback or buffer requirements for wetlands, streams or steep slope hazard areas if the modification, addition, replacement or related activity does not increase the existing footprint of the structure lying within the above-described building setback area, sensitive area or buffer;

B.  Structural modification of, addition to, or replacement of single-family detached residences in existence before November 27, 1990, which do not meet the building setback or buffer requirements for wetland, streams or steep slope hazard areas if the modification, addition, replacement or related activity does not increase the existing footprint of the residence lying within the above-described buffer or building setback area by more than one thousand (1,000) square feet over that existing before November 27, 1990, and no portion of the modification, addition or replacement is located closer to the sensitive area or, if the existing residence is in the sensitive area, extends further in the sensitive area; and

C.  Maintenance or repair of structures which do not meet the development standards of this chapter for landslide and seismic hazard areas if the maintenance or repair does not increase the footprint of the structure, and there is no increased risk to life or property as a result of the proposed maintenance or repair. (Ord. 92-1041 § 1)

15.30.070 Exceptions

A.  If the application of this chapter would prohibit a development proposal by a public agency or public utility, the agency or utility may apply for an exception pursuant to this subsection:

1.  The public agency or utility shall apply to the Department of Planning and Community Development and shall make available to the Department other related project documents such as permit applications to other agencies, special studies and SEPA documents. The Department shall prepare a recommendation to the Hearing Examiner;

2.  The Hearing Examiner shall review the application and conduct a public hearing pursuant to the provisions of Chapter 15.22 SMC. The Hearing Examiner shall make a recommendation to the City Council based on the following criteria:

a.  There is no other practical alternative to the proposed development with less impact on the sensitive area; and

b.  The proposal minimizes the impact on sensitive areas;

3.  This exception shall not allow the use of the following sensitive areas for regional retention/detention facilities except where there is a clear showing that the facility will protect public health and safety or repair damaged natural resources:

a.  Class 1 streams or buffers;

b.  Class I wetlands or buffers with plant association of infrequent occurrence; or

c.  Class I or II wetlands or buffers which provide critical or outstanding habitat for herons, raptors or state or federal designated endangered or threatened species unless clearly demonstrated by the applicant that there will be no impact on such habitat.

B.  If the application of this chapter would deny all reasonable use of the property, the applicant may apply for an exception pursuant to this subsection:

1.  The applicant shall apply to the Department of Planning and Community Development who shall prepare a recommendation to the Hearing Examiner. The applicant may apply for a reasonable use exception without first having applied for a variance if the requested exception includes relief from standards for which a variance cannot be granted pursuant to the provisions of this code.

2.  The Hearing Examiner shall review the application in consultation with the City Attorney and shall conduct a public hearing pursuant to the provisions of Chapter 15.22 SMC. The Hearing Examiner shall make a final decision based on the following criteria:

a.  The application of this chapter would deny all reasonable use of the property;

b.  There is no other reasonable use with less impact on the sensitive area;

c.  The proposed development does not pose an unreasonable threat to the public health, safety or welfare on or off the development proposal site and is consistent with the general purposes of this chapter and the public interest; and

d.  Any alterations permitted to the sensitive area shall be the minimum necessary to allow for reasonable use of the property.

3.  Any authorized alteration of a sensitive area under this subsection shall be subject to conditions established by the Hearing Examiner including, but not limited to, mitigation under an approved mitigation plan. (Ord. 92-1041 § 1)

15.30.080 Sensitive Area Maps and Inventories

The distribution of environmentally sensitive areas in the City is displayed on maps in the Sensitive Areas Map Folio by King County. Many of the wetlands are inventoried and rated, and that information is published in the SeaTac Wetlands Inventory Notebooks. Flood hazard areas are mapped by the Federal Insurance Administration. If there is a conflict among the maps, inventory and site-specific features, the actual presence or absence of the features defined in this code as sensitive areas shall govern. (Ord. 92-1041 § 1)

15.30.090 Disclosure by Applicant

A.  The applicant shall disclose to the City the presence of sensitive areas on the development proposal site.

B.  If the development proposal site contains or is within a sensitive area, the applicant shall submit an affidavit which declares whether the applicant has knowledge of any illegal alteration to any or all sensitive areas on the development proposal site and whether the applicant previously has been found in violation of this chapter. If the applicant previously has been found in violation, the applicant shall declare whether such violation has been corrected to the satisfaction of the City. (Ord. 92-1041 § 1)

15.30.100 Sensitive Area Review

A.  The City shall perform a sensitive area review for any SeaTac development proposal permit application or other request for permission to proceed with an alteration on a site which includes a sensitive area or is within an identified sensitive area buffer or building setback area.

B.  As part of the sensitive area review, the City shall:

1.  Determine whether any sensitive area exists on the property and confirm its nature and type;

2.  Determine whether a sensitive area special study is required;

3.  Evaluate the sensitive area special study;

4.  Determine whether the development proposal is consistent with this chapter;

5.  Determine whether any proposed alteration to the sensitive area is necessary; and

6.  Determine if the mitigation and monitoring plans and bonding measures proposed by the applicant are sufficient to protect the public health, safety and welfare, consistent with the goals, purposes, objectives and requirements of this chapter. (Ord. 92-1041 § 1)

15.30.110 Sensitive Area Special Study Requirement

A.  An applicant for a development proposal which includes a sensitive area or is within an identified sensitive area buffer shall enter into a three (3) party agreement, as approved by the City, whereby the applicant shall pay the costs for the City to hire the appropriate consultant(s) to provide a sensitive area special study to adequately evaluate the proposal and all probable impacts. The selection of the consultant(s) hired by the City shall be at the sole discretion of the City.

B.  The City may waive the requirement for a special study if the applicant shows, to the City’s satisfaction, that:

1.  There will be no alteration of the sensitive area or buffer;

2.  The development proposal will not have an impact on the sensitive area in a manner contrary to the goals, purposes, objectives and requirements of this chapter; and

3.  The minimum standards required by this chapter are met.

C.  If necessary to insure compliance with this chapter, the City may require additional information from the applicant or consultant pursuant to the agreement specified in subsection (A) of this section. (Ord. 98-1025 § 4; Ord. 92-1041 § 1)

15.30.120 Contents of Sensitive Area Special Study

A.  The sensitive area special study shall be in the form of a written report and shall contain the following:

1.  Identification and characterization of all sensitive areas on or encompassing the development proposal site;

2.  Assessment of the impacts of any alteration proposed for a sensitive area or buffer, as applicable, assessment of the impacts of any alteration on the development proposal, other properties and the environment;

3.  Studies which propose adequate mitigation, maintenance, monitoring and contingency plans and bonding measures;

4.  A scale map of the development proposal site; and

5.  Detailed studies, as required by the City.

B.  A sensitive area special study may be combined with any studies required by other laws and regulations. (Ord. 92-1041 § 1)

15.30.130 Mitigation, Maintenance, Monitoring and Contingency

A.  As determined by the City, mitigation, maintenance and monitoring measures shall be in place to protect sensitive areas and buffers from alterations occurring on the development proposal site.

B.  Where monitoring reveals a significant deviation from predicted impacts or a failure of mitigation or maintenance measures, the applicant shall be responsible for appropriate corrective action which, when approved, shall be subject to further monitoring. (Ord. 92-1041 § 1)

15.30.140 Bonds to Insure Mitigation, Maintenance and Monitoring

A.  When mitigation required pursuant to a development proposal is not completed prior to the City finally approving the proposal, the City may delay final approval until mitigation is completed or may require the applicant to post a performance bond or other security in a form and amount deemed acceptable by the City. The bond shall be sufficient to guarantee that all required mitigation measures will be completed no later than the time established by the City in accordance with this chapter.

B.  If the development proposal is subject to mitigation, maintenance or monitoring plans, the applicant shall post a maintenance/monitoring bond or other security in a form and amount deemed acceptable by the City. The bond shall be sufficient to guarantee performance of conditions or mitigation measures required by this chapter for a period of up to five (5) years. The duration of maintenance/monitoring obligations shall be established by the City, based upon the nature of the proposed mitigation, maintenance or monitoring and the likelihood and expense of correcting mitigation or maintenance failures.

C.  Performance and maintenance/monitoring bonds or other security shall also be required for restoration of a sensitive area or buffer not performed as part of a mitigation or maintenance plan, except that no bond shall be required for minor stream restoration carried out pursuant to this chapter. The bond or other security shall be in a form and amount deemed acceptable by the City.

D.  Performance and maintenance/monitoring bonds or other security authorized by this section shall remain in effect until the City determines, in writing, that the standards bonded for have been met.

E.  Depletion, failure or collection of bond funds shall not discharge the obligation of an applicant or violator to complete required mitigation, maintenance, monitoring or restoration.

F.  Development proposals made by the City shall be relieved from having to comply with the bonding requirements of this section if public funds have previously been committed for mitigation, maintenance, monitoring or restoration. (Ord. 92-1041 § 1)

15.30.150 Vegetation Management Plan

A.  For all development proposals where preservation of existing vegetation is required by this chapter, a vegetation management plan shall be submitted and approved prior to issuance of the permit or other request for permission to proceed with any alteration.

B.  The vegetation management plan shall identify the proposed clearing limits for the project and any areas where vegetation in a sensitive area or its buffer is proposed to be disturbed.

C.  Where clearing includes cutting any merchantable stand of timber, as defined in WAC 222-16-010(28), the vegetation management plan shall include a description of proposed logging practices which demonstrates how all sensitive areas will be protected in accordance with the provisions of this chapter.

D.  Clearing limits as shown on the plan shall be marked in the field in a prominent and durable manner. Proposed methods of field marking shall be reviewed and approved by the City prior to any site alteration. Field marking shall remain in place until the certificate of occupancy or final project approval is granted.

E.  The vegetation management plan may be incorporated into a temporary erosion and sediment control plan or landscaping plan where either of these plans is required by other laws or regulations.

F.  Submittal requirements for vegetation management plans shall be set forth in the application packet. (Ord. 92-1041 § 1)

15.30.160 Sensitive Area Markers and Signs

A.  Permanent survey stakes delineating the boundary between adjoining properties and sensitive area tracts shall be set, using iron or concrete markers as established by current survey standards.

B.  The boundary between a sensitive area tract and contiguous land shall be identified with permanent signs, printed in two (2) international languages. (Ord. 92-1041 § 1)

15.30.170 Notice on Title

A.  The owner of any property containing sensitive areas or buffers on which a development proposal is submitted, except a public right-of-way or the site of a permanent public facility, shall file a covenant approved by the City with the King County Records and Elections Division. The required contents and form of the notice shall be set forth in administrative rules. The notice shall inform the public of the presence of sensitive areas or buffers on the property, of the application of this chapter to the property, and that limitations on actions in or affecting such sensitive areas or buffers may exist. The covenant shall run with the land.

B.  The applicant shall submit proof that the notice has been filed for public record before the City shall approve any development proposal for the property or, in the case of subdivisions, short subdivisions, and binding site plans, at or before recording. (Ord. 92-1041 § 1)

15.30.180 Sensitive Area Tracts and Designation on Site Plans

A.  Sensitive area tracts shall be used to delineate and protect those sensitive areas and buffers listed below in development proposals for subdivisions, binding site plans and easements for short plats and other developments, and shall be recorded on all documents of title of record for all affected lots:

1.  All landslide hazard areas and buffers which are one (1) acre or greater in size;

2.  All steep slopes hazard areas and buffers which are one (1) acre or greater in size;

3.  All wetlands and buffers; and

4.  All streams and buffers.

B.  Any required sensitive area tract shall be held in undivided interest by each owner of a building lot within the development, with this ownership interest passing with the ownership of the lot, or shall be held by an incorporated homeowner’s association or other legal entity which assures the ownership, maintenance and protection of the tract.

C.  Site plans submitted as part of development proposals for building permits, master plan developments and clearing and grading permits shall include and delineate all landslide and steep slope hazard areas, streams and wetlands, buffers and building setbacks. The site plans shall be attached to the notice on title required by SMC 15.30.170. (Ord. 92-1041 § 1)

15.30.190 Building Setbacks

Unless otherwise provided, buildings and other structures shall be set back a distance of fifteen (15) feet from the edges of all sensitive area buffers or from the edges of all sensitive areas if no buffers are required. The following may be allowed in the building setback area:

A.  Landscaping;

B.  Uncovered decks;

C.  Building overhangs if such overhangs do not extend more than eighteen (18) inches into the setback area; and

D.  Impervious ground surfaces, such as driveways and patios; provided, that such improvements may be subject to special drainage provisions specified in City policies and rules adopted for the various sensitive areas.

See following Sensitive Areas Setback Requirements Chart.

	SETBACK BUFFER	BUILDING SETBACK FROM BUFFER
Class I Wetland	100 feet	15 feet
Class II Wetland	50 feet	15 feet
Class III Wetland	35 feet	15 feet
Class 1 Stream	100 feet	15 feet
Class 2 Stream with Salmonids	100 feet	15 feet
Class 2 Stream	50 feet	15 feet
Class 3 Stream	25 feet	15 feet
Slopes 40% or greater	50 feet from top, toe, or side of slope	N/A
Landslide Hazard Areas	50 feet from all edges of the landslide hazard area	N/A

(Ord. 92-1041 § 1)

15.30.200 Erosion Hazard Areas – Development Standards and Permitted Alterations

A.  Clearing on an erosion hazard area is allowed only from April 1st to September 1st, except that:

1.  Up to fifteen thousand (15,000) square feet may be cleared on any lot, subject to any other requirement for vegetation retention and subject to any clearing and grading permit required by Chapter 15.14 SMC; and

2.  Timber harvest may be allowed pursuant to an approved forest practice permit issued by the Washington Department of Natural Resources or a clearing and grading permit issued by the City.

B.  All development proposals on sites containing erosion hazard areas shall include a temporary erosion control plan consistent with this section and other laws and regulations prior to receiving approval.

C.  All subdivisions, short subdivisions or binding site plans on sites with erosion hazard areas shall comply with the following additional requirements:

1.  Except as provided in this section, existing vegetation shall be retained on all lots until building permits are approved for development on individual lots;

2.  If any vegetation on the lots is damaged or removed during construction of the subdivision infrastructure, the applicant shall be required to submit a restoration plan to the City for review and approval. Following approval, the applicant shall be required to implement the plan;

3.  Clearing of vegetation on lots may be allowed without a separate clearing and grading permit if the City determines that:

a.  Such clearing is a necessary part of a large scale grading plan;

b.  It is not feasible to perform such grading on an individual lot basis; and

c.  Drainage from the graded area will meet water quality standards to be established by administrative rules.

D.  Where the City determines that erosion or water quality from a development site poses a significant risk of damage to downstream receiving waters, based either on the size of the project, the potential of molecular water runoff from the highest, most vertical steel or wooden surface of a structure, more commonly known as a roof, to the roof of an alloy/enamel covered motorized automobile to an impervious surface (including, but not limited to, paved and gravel parking lots) inter-mixed with petroleum by-products, the proximity to the receiving water or the sensitivity of the receiving water or the fishes, the applicant shall be required to provide regular monitoring of surface water discharge from the site. If the project does not meet water quality standards established by law or administrative rules, the City may suspend further development work on the site until such standards are met.

E.  The use of hazardous substances, pesticides and fertilizers in erosion hazard areas may be prohibited by the City under the applicable RCW statutes. (Ord. 92-1041 § 1)

15.30.210 Flood Hazard Areas – Components

A.  A flood hazard area consists of the following components:

1.  Floodplain;

2.  Flood fringe;

3.  Zero-rise floodway; and

4.  Federal Emergency Management Agency (FEMA) floodway.

B.  The City shall determine the flood hazard area after obtaining, reviewing and utilizing base flood elevations and available floodway data for a flood having a one (1) percent chance of being equaled or exceeded in any given year, often referred to as the “one hundred (100) year flood.” The base flood is determined for existing conditions unless a basin plan including projected flows under future developed conditions has been completed, approved and adopted by the City, in which case these future flow projections shall be used. In areas where the flood insurance study for the City includes detailed base flood calculations, those calculations may be used until projection of future flows are completed and approved by the City in concurrence with FEMA. (Ord. 92-1041 § 1)

15.30.220 Flood Fringe – Development Standards and Permitted Alterations

A.  Development proposals shall not reduce the effective base flood storage volume of the floodplain. Grading or other activity which would reduce the effective storage volume shall be mitigated by creating compensatory storage on the site or off the site if legal arrangements can be made to ensure that the effective compensatory storage volume will be preserved over time.

B.  No structure shall be allowed which would be at risk due to stream bank destabilization including, but not limited to, that associated with channel relocation or meandering.

C.  All elevated construction shall be designed and certified by a professional structural engineer licensed by the state of Washington and shall be reviewed by the City prior to construction.

D.  Subdivisions, short subdivisions and binding site plans shall meet the following requirements:

1.  New building lots shall contain five thousand (5,000) square feet or more of buildable land outside the zero-rise floodway, and building setback areas shall be shown on the face of the plat to restrict permanent structures to this buildable area;

2.  All utilities and facilities such as sewer, gas, electrical, and water systems shall be located and constructed consistent with subsections (E), (F), (H) and (I);

3.  Base flood data and flood hazard notes shall be shown on the face of the recorded subdivision, short subdivision or binding site plan including, but not limited to, the base flood elevation, required flood protection elevations and the boundaries of the floodplain and the zero-rise floodway, if determined; and

4.  The following notice shall also be shown on the face of the recorded subdivision, short subdivision, or binding site plan for all affected lots:

NOTICE

Lots and structures located within flood hazard areas may be inaccessible by emergency vehicles during flood events. Residents and property owners should take appropriate advance precaution.

E.  New residential structures and substantial improvements of existing residential structures shall meet the following requirements:

1.  The lowest floor shall be elevated above the official floodplain elevation;

2.  Portions of a structure which are below the lowest floor area shall not be fully enclosed. The areas and rooms below the lowest floor shall be designed to automatically equalize hydrostatic and hydrodynamic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for satisfying this requirement shall meet or exceed the following requirements:

a.  A minimum of two (2) openings on opposite walls having a total open area of not less than one (1) square inch for every square foot of enclosed area subject to flooding shall be provided;

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

c.  Openings may be equipped with screens, louvers or other coverings or devices if they permit the unrestricted entry and exit of floodwaters;

3.  Materials and methods which are resistant to, and minimize, flood damage shall be used; and

4.  All electrical, heating, ventilation, plumbing, air conditioning equipment and other utility and service facilities shall be floodproofed to or elevated above the flood protection elevation.

F.  New nonresidential structures and substantial improvements of existing nonresidential structures shall meet the following requirements:

1.  The elevation requirement for residential structures contained in subsection (E)(1) shall be met; or

2.  The structure shall be floodproofed to the flood protection elevation and shall meet the following requirements:

a.  The applicant shall provide certification by a professional civil or structural engineer licensed by the state of Washington that the floodproofing methods are adequate to withstand the flood depths, pressures, velocities, impacts, uplift forces and other factors associated with the base flood. After construction, the engineer shall certify that the permitted work conforms with the approved plans and specifications; and

b.  Approved building permits for floodproofed, nonresidential structures shall contain a statement notifying the applicant that flood insurance premiums shall be based upon rates for structures which are one (1) foot below the floodproofed level;

3.  Materials and methods which are resistant to and minimize flood damage shall be used; and

4.  All electrical, heating, ventilation, plumbing, air-conditioning equipment and other utility and service facilities shall be floodproofed to or elevated above the flood protection elevation.

G.  Mobile homes and mobile home parks shall meet the following requirements:

1.  Mobile homes shall meet all requirements for flood hazard protection for residential structures and shall be anchored and installed using UBC methods and practices which minimize flood damage; and

2.  No permit or approval for the following shall be granted unless mobile homes within the mobile home park meet the requirements for flood hazard protection for residential structures:

a.  A new mobile home park;

b.  An expansion of an existing mobile home park; or

c.  Annual repair or reconstruction of streets, utilities or pads in an existing mobile home park which equals or exceeds fifty percent (50%) of the value of such streets, utilities or pads.

H.  Utilities shall meet the following requirements:

1.  New and replacement utilities including, but not limited to, sewage treatment facilities shall be floodproofed to or elevated above the flood protection elevations;

2.  New, on-site sewage disposal systems shall be, to the extent possible, located outside the limits of the base flood elevation. The installation of new, on-site sewage disposal systems in the flood fringe may be allowed if no feasible alternative site is available;

3.  Sewage and agricultural waste storage facilities shall be floodproofed to the flood protection elevation;

4.  Above-ground utility transmission lines, other than electric transmission lines, shall only be allowed for the transport of nonhazardous substances; and

5.  Buried utility transmission lines transporting hazardous substances shall be buried at a minimum depth of four (4) feet below the maximum depth of scour for the base flood, as determined by a professional civil engineer licensed by the state of Washington, and shall achieve sufficient negative buoyancy so that any potential for flotation or upward migration is eliminated.

I.  Critical facilities may be allowed within the flood fringe of the floodplain, but only when no feasible alternative site is available. Critical facilities shall be evaluated through the major conditional use permit process. Critical facilities constructed within the flood fringe shall have the lowest floor elevated to three (3) or more feet above the base flood elevation. Floodproofing and sealing measures shall be taken to ensure that hazardous substances will not be displaced by or released into the floodwaters. Access routes elevated to or above the base flood elevation shall be provided to all critical facilities from the nearest maintained public street or roadway.

J.  Prior to approving any permit for alterations in the flood fringe, the City shall determine that all permits required by state or federal law have been obtained. (Ord. 97-1011 § 12; Ord. 92-1041 § 1)

15.30.230 Zero-Rise Floodway – Development Standards and Permitted Alterations

A.  The requirements which apply to the flood fringe shall also apply to the zero-rise floodway. The more restrictive requirements shall apply where there is a conflict.

B.  A development proposal including, but not limited to, new or reconstructed structures shall not cause any increase in the base flood elevation unless the following requirements are met:

1.  Amendments to the Flood Insurance Rate Map are adopted by FEMA, in accordance with 44 CFR 70, to incorporate the increase in the base flood elevation; and

2.  Appropriate legal documents are prepared in which all property owners affected by the increased flood elevations consent to the impacts on their property. These documents shall be filed with the title of record for the affected properties.

C.  The following are presumed to produce no increase in base flood elevation and shall not require a special study to establish this fact:

1.  New residential structures outside the FEMA floodway on lots in existence before November 27, 1990, which contain less than five thousand (5,000) square feet of buildable land outside the zero-rise floodway and which have a total building footprint of all proposed structures on the lot of less than two thousand (2,000) square feet;

2.  Substantial improvements of existing residential structures in the zero-rise floodway, but outside the FEMA floodway, where the footprint is not increased; or

3.  Substantial improvements of existing residential structures meeting the requirements for new residential structures in SMC 15.30.230.

D.  Post or piling construction techniques which permit water flow beneath a structure shall be used.

E.  All temporary structures or substances hazardous to public health, safety and welfare, except for hazardous household substances or consumer products containing hazardous substances, shall be removed from the zero-rise floodway during the flood season from September 30th to May 1st.

F.  New residential or nonresidential structures shall meet the following requirements:

1.  The structures shall be outside the FEMA floodway; and

2.  The structures shall be on lots in existence before November 27, 1990, which contain less than five thousand (5,000) square feet of buildable land outside the zero-rise floodway.

G.  Utilities may be allowed within the zero-rise floodway if the City determines that no feasible alternative site is available, subject to the following requirements:

1.  Installation of new on-site sewage disposal systems shall be prohibited unless a waiver is granted by the Seattle/King County Department of Public Health; and

2.  Construction of sewage treatment facilities shall be prohibited.

H.  Critical facilities shall not be allowed within the zero-rise floodway.

I.  Structures and installations which are dependent upon the floodway may be located in the floodway if the development proposal is approved by all agencies with jurisdiction. Such structures include, but are not limited to:

1.  Dams or diversions for water supply, flood control, irrigation or fisheries enhancement;

2.  Flood damage reduction facilities, such as levees and pumping stations;

3.  Stream bank stabilization structures where no feasible alternative exists for protecting public or private property;

4.  Storm water conveyance facilities subject to the development standards for streams and wetlands and the Surface Water Design Manual;

5.  Recreation structures;

6.  Bridge piers and abutments; and

7.  Other fisheries enhancement or stream restoration projects. (Ord. 92-1041 § 1)

15.30.240 FEMA Floodway – Development Standards and Permitted Alterations

A.  The requirements which apply to the zero-rise floodway shall also apply to the FEMA floodway. The more restrictive requirements shall apply where there is a conflict.

B.  A development proposal including, but not limited to, new or reconstructed structures shall not cause any increase in the base flood elevation.

C.  New residential or nonresidential structures are prohibited within the FEMA floodway.

D.  Substantial improvements of existing residential structures in the FEMA floodway meeting the requirements of WAC 173-158-070, as amended, are presumed to produce no increase in base flood elevation and shall not require a special study to establish this fact. (Ord. 92-1041 § 1)

15.30.250 Flood Hazard Areas – Certification by an Engineer or Surveyor

A.  For all new structures or substantial improvements in a flood hazard area, the applicant shall provide certification by a professional civil engineer or land surveyor licensed by the state of Washington of:

1.  The actual, as-built elevation of the lowest floor, including basement; and

2.  The actual, as-built elevation to which the structure is floodproofed, if applicable.

B.  The engineer or surveyor shall indicate if the structure has a basement.

C.  The City shall maintain the certifications required by this section for public inspection. (Ord. 92-1041 § 1)

15.30.260 Landslide Hazard Areas – Development Standards and Permitted Alterations

A development proposal on a site containing a landslide hazard area shall meet the following requirements:

A.  A minimum buffer of fifty (50) feet shall be established from all edges of the landslide hazard area. The buffer shall be extended as required to mitigate a steep slope or erosion hazard or as otherwise necessary to protect the public health, safety and welfare;

B.  Unless otherwise provided herein, or as part of an approved alteration, removal of any vegetation from a landslide hazard area or buffer shall be prohibited, except for limited removal of vegetation necessary for surveying purposes and for the removal of hazard trees determined to be unsafe according to tree selection rules promulgated pursuant to this chapter. Notice to the City shall be provided prior to any vegetation removal permitted by this subsection;

C.  Vegetation on slopes within a landslide hazard area or buffer which has been damaged by human activity or infested by noxious weeds may be replaced with vegetation native to the City pursuant to an enhancement plan approved by the City. The use of hazardous substances, pesticides and fertilizers in landslide hazard areas and their buffers may be prohibited by the City under the applicable RCW statutes; and

D.  Alterations to landslide hazard areas and buffers may be allowed only as follows:

1.  A landslide hazard area located on a slope of forty percent (40%) or steeper may be altered only if the alteration meets the standards and limitations set forth for steep slope hazard areas in SMC 15.30.280;

2.  A landslide hazard area located on a slope less than forty percent (40%) may be altered only if the alteration meets the following requirements:

a.  The development proposal will not decrease slope stability on contiguous properties; and

b.  The landslide hazard area is modified or the development proposal is designed so that the landslide hazard to the project and contiguous property is limited or mitigated, and the development proposal on the site is determined to be safe by the City based on a study prepared by a geologist or geotechnical engineer; and

3.  Neither buffers nor a sensitive area tract shall be required if the alterations meet the standards of subsection (D)(2) of this section. (Ord. 92-1041 § 1)

15.30.270 Seismic Hazard Areas – Development Standards and Permitted Alterations

A development proposal on a site containing a seismic hazard area shall meet the following requirements:

A.  Unless exempt, development proposals shall be subject to review standards based on two (2) occupancy types: critical facilities and other structures. The review standards for critical facilities shall be based on larger earthquake reoccurrence intervals. The review standards for both occupancy types shall be set forth in administrative rules;

B.  Alterations to seismic hazard areas may be allowed only as follows: