Chapter 17B.18
SHORELINE MODIFICATION REGULATIONS

Sections:

17B.18.010    Purpose.

17B.18.020    Permitted modifications.

17B.18.030    Upland clearing, grading, and fill—Landward of the OHWM.

17B.18.040    Dredging and dredge disposal.

17B.18.050    In-water fill.

17B.18.060    Shoreline stabilization.

17B.18.070    Beach enhancement and in-water mitigation projects.

17B.18.080    Shoreline restoration projects.

17B.18.010 Purpose.

A.    The purpose of this chapter is to establish permitted and conditional uses by zone for modifications within the shoreline area of the city.

B.    Permitted and conditional modifications in the shorelines of the state shall be designed and constructed in a manner to minimize any resultant damage to the ecology and environment of the shoreline area and any interference with the public’s use of the water.

C.    Proposed shoreline modifications must comply with the Mukilteo shoreline management program’s goals and policies contained in Chapter 3 and environment designations contained in Chapter 4 of the Mukilteo shoreline master program as well as specific shoreline critical area regulations, and shoreline modification activity provisions contained in this section. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)

17B.18.020 Permitted modifications.

The Shoreline Permitted Use Matrix summarizes the permitted (P), special use permit (SUP), conditional use (C), and prohibited (X or no mark) modifications in all shoreline designations.

P= Permitted Use

SUP = Special Use Permit

C= Conditional Use Permit

X= Prohibited Use

Urban Waterfront

Urban Waterfront Park

Urban Conservancy

Aquatic Urban

Aquatic Urban Conservancy

Urban Lakefront

Urban Railroad

New Beach Restoration/Enhancement

P

P

P

P

P

P

P

Bioengineering

P

P

P

P

P

P

P

Revetments2

P1/C2

P1/C2

C

C2/X

C2/X

C2/X

C

Bulkheads2

C2/X

C2/X

C2/X

C2/X

C2/X

C2/X

C

Breakwaters/Rock2

P1/C2

C2/X

C2/X

C2/X

C2/X

C2/X

C

Weirs/Groins2

C2/X

C2/X

C2/X

C2/X

C2/X

C2/X

X

Dredging3

P3/C

P3/C

P3/C

P3/C

P3/C

P3/C

P3/C

Hazardous Waste Cleanup

P

P

P

P

P

P

P

Fill (Waterward of OHWM)

C

C

C

C

C

C

C

Repairs of Existing Shoreline Modifications

P

P

P

P

P

P

P

Soft Construction

C

C

C

C

C

C

C

Railroad

C

C

C

C

C

X

C

Essential Public Facilities—In-Water Work

C/SUP

C/SUP

C/SUP

C/SUP

C/SUP

C/SUP

C/SUP

Utilities

P

P

P

C

C

C

P

P1 =    Master plan required.

C2 =    Hard stabilization is only allowed with a conditional use permit as provided for in WAC 173-26-231(3)(a)(iii)(B)(i) and Section 17B.18.060. Otherwise hard stabilization is prohibited.

P3 =    Dredging is only allowed as a permitted use if associated with shoreline restoration or beach enhancement/nourishment projects.

(Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)

17B.18.030 Upland clearing, grading, and fill—Landward of the OHWM.

A.    All clearing and grading activities shall be limited to the minimum necessary per Chapter 15.16 and the critical area provisions of this program.

B.    Clearing, grading, and fill activities may be permitted only when associated with an approved shoreline substantial development permit or shoreline conditional use permit. Temporary stockpiling of materials (up to six months) is allowed in association with the tank farm redevelopment if there are no adverse impacts to water quality, critical areas or their buffers due to these activities. Upon completion of construction, remaining cleared areas shall be replanted as approved by the city. Replanted areas shall be monitored and maintained to ensure the reestablishment of vegetation.

C.    Normal nondestructive pruning and trimming of vegetation for maintenance purposes shall not be subject to the regulations contained in this section. Clearing by hand-held equipment of invasive, nonnative shoreline vegetation or plants listed on the State Noxious Weed List is permitted in shoreline locations if native vegetation is promptly reestablished in the disturbed area. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)

17B.18.040 Dredging and dredge disposal.

A.    New development shall be sited and designed to avoid or, if not possible, to minimize the need for new dredging and/or continued need for maintenance dredging and/or placement of fill in the nearshore, except for beach enhancement activities.

B.    Dredging and dredge material disposal shall be done in a manner which avoids or minimizes significant ecological impacts, and impacts which cannot be avoided should be mitigated in a manner that ensures no net loss of shoreline ecological functions.

C.    New development shall be sited and designed to avoid or, if that is not possible, to minimize the need for new and maintenance dredging. Dredging for the purpose of establishing, expanding, or relocating or reconfiguring navigation channels and basins should be allowed where necessary for assuring safe and efficient accommodation of existing navigational uses and then only when significant ecological impacts are minimized and when mitigation is provided. Maintenance dredging of established navigation channels and basins should be restricted to maintaining previously dredged and/or existing authorized location, depth, and width.

D.    Dredging waterward of the ordinary high water mark for the primary purpose of obtaining fill material shall not be allowed, except when the material is necessary for the restoration of ecological functions. When allowed, the site where the fill is to be placed must be located waterward of the ordinary high water mark. The project must be either associated with a MTCA or CERCLA habitat restoration project or, if approved through a shoreline conditional use permit, any other significant habitat enhancement project.

E.    Dredging and dredge disposal allowed below the ordinary high water mark (OHWM) is regulated by the U.S. Army Corps of Engineers (USACE) and may be regulated by state agencies that may include WDFW and DOE.

F.    Dredging shall be accomplished in a manner that avoids or minimizes environmental impacts.

G.    Dredging operations shall be planned and conducted to minimize interference with navigation and adverse impacts to other shoreline uses, commercial fisheries, and upland properties.

H.    Dredging for the sole purpose of obtaining fill material is prohibited.

I.    Dredging in association with shoreline restoration or beach enhancement/nourishment that has been permitted is allowed.

J.    Deposition of dredge spoils (not including landslide materials impacting BNSF railroad operations) in water areas that adversely affect fish and shellfish resources is prohibited except where materials are being used for habitat improvement or substrate improvements or for redistribution of materials.

K.    The location of dredge disposal shall be approved by U.S. Army Corps of Engineers and appropriate state agencies (e.g., WDFW and DOE). (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)

17B.18.050 In-water fill.

A.    Fill waterward of the ordinary high water mark (OHWM) is prohibited, except for water-dependent essential public facilities, water-dependent uses, public access, recreational uses, and habitat and beach restoration projects that are otherwise consistent with the SMP and have been approved by WDOE, WDFW and U.S. Army Corps of Engineers. The use of bridge or pier alternatives must be determined to be unfeasible if fill is to be allowed.

B.    Non-water-oriented uses are prohibited from filling below the OHWM.

C.    Fill below the OHWM may be allowed for the above uses after approval of the WDOE, U.S. Army Corps of Engineers and consultation with WDFW, demonstrating that the proposed development/fill will not create a significant environmental impact. Mitigation may be required as part of this activity.

D.    When fill is permitted, the fill shall be restricted to the minimum amount necessary to provide for the proposed use and shall be linked to a specific development proposal permitted under the SMP. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)

17B.18.060 Shoreline stabilization.

Shoreline stabilization includes actions taken to address erosion impacts to property, dwellings, businesses, or essential structures caused by manmade processes such as boat wakes and natural processes, such as current, flood, wind, or wave action. These include structural and nonstructural methods. Nonstructural methods include building setbacks, relocation of the structure to be protected, erosion and ground water management, planning and regulatory measures to avoid the need for structural stabilization. Structural methods include “hard” and “soft” structural stabilization measures.

A.    Maintenance and Repair. Normal maintenance and repair actions are not exempt from substantial development permits if they cause substantial adverse effects to shoreline resources or the environment. Additions to or increases in size of existing shoreline stabilization measures shall be considered new structures. Some shoreline stabilization measures for single-family residences may be exempt from a shoreline substantial development permit in accordance with WAC 173-27-040(2). However, such measures must comply with the provisions of this SMP.

1.    An existing shoreline stabilization structure shall not be replaced with a similar structure unless there is need to protect primary structures from erosion caused by currents or waves and a nonstructural measure is not feasible. The replacement structure shall be designed, located, sized, and constructed to minimize harm to ecological functions. Replacement walls or bulkheads shall not encroach waterward of the OHWM unless there are overriding safety or environmental concerns. In such cases, the replacement structure shall abut the existing shoreline stabilization structure.

2.    When an existing bulkhead is being repaired or replaced by construction of a vertical wall fronting the existing wall, it shall be constructed no farther waterward of the existing bulkhead than is necessary for construction of new footings. When a bulkhead has deteriorated such that an OHWM has been established by the presence and action of water landward of the bulkhead, then the replacement bulkhead must be located at or landward of the actual OHWM.

3.    Replacement bulkheads may be built to the height of the original bulkhead.

B.    New Development and/or Structures.

1.    New development shall, where feasible, be located and designed to eliminate the need for concurrent or future shoreline stabilization. New non-water-dependent development that would require shoreline stabilization that would cause significant adverse impacts to adjacent or down-current properties is prohibited.

2.    New development, including single-family residences, that includes structural shoreline stabilization will not be allowed unless all of the conditions below are met:

a.    The need to protect the development from damage due to erosion caused by natural processes, such as currents and waves, and by manmade processes such as boat wakes, is demonstrated through a geotechnical report.

b.    The erosion is not being caused by upland conditions, such as loss of vegetation and drainage.

c.    Nonstructural measures, such as placing the development farther from the shoreline, planting vegetation, low impact development measures, or installing on-site drainage improvements, are not feasible or not sufficient.

d.    The structure will not result in a net loss of shoreline ecological functions.

3.    New development on steep slopes or bluffs shall be set back sufficiently to ensure that shoreline stabilization will not be needed during the life of the structure, as demonstrated by a geotechnical analysis.

C.    New or Expanded Shoreline Stabilization Measures.

1.    New stabilization measures are not allowed except to protect or support an existing or approved development, as necessary for human safety, for the restoration of ecological functions, or for hazardous substance remediation pursuant to Chapter 70.105D RCW. The construction of a bulkhead for the primary purpose of retaining or creating dry land that is not specifically authorized as a part of the permit is prohibited.

2.    New or enlarged structural shoreline stabilization measures for an existing development or residence shall not be allowed unless there is conclusive evidence, documented by a geotechnical analysis, that the structure is in danger from shoreline erosion caused by currents, waves, or boat wakes. Normal sloughing, erosion of steep bluffs, or shoreline erosion itself, without a geotechnical report, is not demonstration of need. The geotechnical report must include estimates of erosion rates and damage within three years and must evaluate on-site drainage issues and address drainage problems away from the shoreline edge before considering structural shoreline stabilization. The project design and analysis must also evaluate vegetation enhancement and low impact development measures as a means of reducing undesirable erosion.

3.    “Hard” structural shoreline stabilization measures, such as bulkheads, are not allowed unless the applicant can demonstrate through a geotechnical report that “soft” structural measures such as vegetation or beach enhancement, or nonstructural measures, such as additional building setbacks, are not feasible.

4.    Where structural shoreline stabilization measures are demonstrated to be necessary, the size of stabilization measures shall be limited to the minimum necessary. The city’s shoreline administrator may require that the proposed structure be altered in size or design or impacts otherwise mitigated. Impacts to sediment transport shall be avoided or minimized.

5.    The city’s shoreline administrator will require mitigation of adverse impacts to shoreline functions such as the inclusion of vegetation conservation as part of shoreline stabilization, where feasible. In order to determine acceptable mitigation, the city’s shoreline administrator may require the applicant to provide necessary environmental information and analysis, including a description of the existing OHWM, based on field indicators. The determination of the OHWM is based on a site-specific investigation using field indicators and in case of a disagreement as to its location, the ultimate decision on the OHWM shall rest with Ecology. The OHWM determination along with a restoration plan outlining how proposed mitigation measures would result in no net loss of shoreline ecological functions shall be submitted for review.

6.    Shoreline stabilization measures that incorporate ecological restoration through the placement of rocks, gravel or sand, and native shoreline vegetation may be allowed. Soft shoreline stabilization that restores ecological functions may be permitted waterward of the OHWM.

7.    Following completion of shoreline modification activities, disturbed shoreline areas shall be restored to preproject conditions to the greatest extent possible. Vegetation conservation measures, including the planting of native vegetation along the shoreline, are a condition of all new bulkhead and replacement construction. Plantings shall consist of native grasses, shrubs, and trees as approved by the city’s shoreline administrator in keeping with preexisting or typical naturally occurring bank vegetation. Vegetation shall be fully reestablished within three years. All revegetation projects shall include a program for monitoring and maintenance. Areas which fail to adequately reestablish vegetation shall be replanted with approved plants until the plantings are viable.

D.    Design of Shoreline Stabilization Measures.

1.    Bulkhead design and development shall conform to all other applicable city and state agency policies and regulations, including the Washington State Department of Fish and Wildlife criteria governing the design of bulkheads.

2.    Gabions (wire mesh filled with concrete or rocks) are prohibited, except as a conditional use where it is determined that gabions are the least environmentally disruptive method of shoreline stabilization.

3.    Stairs and other allowed structures may be built as integral to a bulkhead but shall not extend waterward of the bulkhead or structure unless it is necessary to access the shoreline or a use or structure is otherwise allowed over water.

4.    Bulkheads shall be designed to permit the passage of surface or ground water without causing ponding or over-saturation of retained soil/materials of lands above the OHWM.

5.    Adequate toe protection and proper footings shall be provided to ensure bulkhead stability without relying on additional riprap.

E.    Materials and Dimensional Standards. New bulkheads and other shoreline stabilization structures shall not be constructed higher than twenty-four inches above the OHWM or, if the bulkhead is set back from the shoreline, twenty-four inches above grade at the base of the bulkhead or structure. On steep slopes, new bulkheads may be built taller than twenty-four inches high if necessary to meet the existing slope.

F.    Essential public facilities may deviate from these standards so long as they provide proof to the city, state and federal agencies that the facility cannot be reasonably built or maintained by meeting these standards and adequate mitigation is provided to compensate for any ecological impacts. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)

17B.18.070 Beach enhancement and in-water mitigation projects.

A.    Beach enhancement and restoration projects shall be permitted when it is demonstrated that no significant long-term change in littoral drift or redirection of waves, current, or sediment that will adversely affect adjacent properties or habitat will result. Repetitive enhancement is encouraged in smaller quantities rather than a large project done all at once.

B.    Design alternatives for beach enhancement shall be based on best available science or accepted practice at that time, using WDFW, DOE, and USACE (if within USACE jurisdiction) staff advice and consultation to design and approve the enhancement alternative.

C.    Beach enhancement activities shall not result in the creation of additional dry land for development purposes, but can be used to improve public access or to allow for the planting of riparian vegetation and shall not extend waterward of the OHWM more than necessary to achieve the desired stabilization and/or beach nourishment or the reduction in shoreline/nearshore scouring.

D.    Beach enhancement waterward of OHWM requires the approval of the WDOE, WDFW and the USACE (if within USACE jurisdiction) to ensure that it does not prevent spawning or nesting, destroy breeding habitat of priority species, or is used in areas where littoral drift of enhancement materials will adversely affect adjacent spawning grounds.

E.    Beach enhancement shall provide opportunities for normal public use of the shoreline beyond the construction period. Any new public access must be compatible with approved beach enhancement activities. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)

17B.18.080 Shoreline restoration projects.

Shoreline restoration projects include those activities proposed and conducted specifically for purpose of establishing, restoring or enhancing habitat along the shoreline. The following regulations apply under this section:

A.    Establishment and/or enhancement of native vegetation is required for all work waterward of the ordinary high water mark.

B.    Projects involving land disturbance activities, both waterward and upland of the ordinary high water mark, shall remove nonnative or invasive plants listed on the Snohomish County noxious weed list, unless otherwise authorized by the city.

C.    Conversion of hard structural shoreline stabilization to soft shoreline stabilization shall be required per Section 17B.18.060, Shoreline stabilization.

D.    Implementation of any project or activity identified in the city’s restoration plan shall be permitted.

E.    Implementation of any project or activity identified in the WRIA 8 or 7 plans shall be permitted. (Ord. 1427 § 3 (Exh. C) (part), 2019: Ord. 1295 § 10 (Exh. 1B) (part), 2011)