Chapter 21.30
SHORELINE MODIFICATION
Sections:
21.30.010 Flood hazard reduction.
21.30.020 Dredging and dredge material disposal.
21.30.030 Shoreline stabilization (bulkheads and revetments).
21.30.040 Clearing and grading.
21.30.060 Ecological function and habitat enhancement.
21.30.070 In-stream structures.
21.30.005 General provisions.
Shoreline modifications are generally related to construction of a physical element such as a levee, bulkhead, or pier at or near the river’s edge or extending into the channel. Other shoreline modification actions include dredging, filling, or vegetation clearing in the shoreline jurisdiction. Modifications are usually undertaken in support of or in preparation for an allowed shoreline use or development. (Ord. 2002 § 4 (Exh. B), 2019).
21.30.010 Flood hazard reduction.
Flood hazard reduction is a priority for the city of Pacific. However, hazard reduction must be accomplished in accordance with provisions for no net loss of ecological functions and shoreline restoration.
A. New structural flood hazard reduction measures allowed only:
Where demonstrated to be necessary and when nonstructural methods are infeasible and mitigation is accomplished and landward of associated wetlands and buffer areas except where no alternative exists as documented in a geotechnical analysis.
B. All flood control shall conform to Chapter 23.40 PMC, Flood Control.
C. Preferred methods of flood hazard reduction should apply to all new or substantially altered flood hazard measures and shall be designed to restore natural resources associated with streams, restore natural stream channel functions, and overflow corridors where they will result in lower flood peaks and velocities.
D. New or substantially altered structural flood hazard reduction measures, such as dikes, levees, berms and similar flood control structures, shall be placed landward of the floodway as determined by the U.S. Army Corps of Engineers and the state of Washington and Department of Ecology, set back from the OHWM, and located landward of associated wetlands and designated conservation areas to the maximum extent feasible.
E. Dikes, levees, berms and similar flood control structures shall be shaped and planted with vegetation suitable for wildlife habitat.
F. Removal of gravel from the river channel for flood management purposes may be allowed only as part of an adopted integrated flood control management program that demonstrates that other flood hazard reduction strategies would not be effective in the absence of gravel removal.
G. Public access shall be dedicated and improved in all publicly financed or subsidized flood hazard reduction programs unless the criteria of PMC 21.20.040 for modification of public access requirements are met.
H. New or expanding development or uses in the shoreline, including subdivision of land, that would likely require new structural flood control works within a stream, channel migration zone, or floodway should not be allowed, except as permitted within WAC 173-26-221(3)(b) and (3)(c)(i). (Ord. 2002 § 4 (Exh. B), 2019).
21.30.020 Dredging and dredge material disposal.
A. Dredging for the sole purpose of obtaining fill material or aggregate resources is prohibited.
B. Dredging shall be conditionally permitted in the following situations:
1. In conjunction with a water-dependent use of water bodies or adjacent shorelands; and
2. For projects associated with a project adopted as part of the applicable flood hazard control plan MTCA or CERCLA habitat restoration; or
3. Any other significant restoration effort approved by a shoreline CUP.
C. Dredging in wetlands is prohibited unless it is part of an approved habitat restoration or enhancement project.
D. Dredged materials must be deposited on an approved upland site outside of the shoreline jurisdiction.
E. Dredging and dredge disposal within the SMZ shall be permitted only where it is demonstrated that the proposed actions will not:
1. Result in significant and/or ongoing damage to water quality, fish, and other essential aquatic biological elements;
2. Adversely alter natural drainage and circulation patterns, currents, river and tidal flows or significantly reduce flood water capacities; or
3. Cause other significant adverse ecological impacts.
F. Dredging shall utilize techniques that cause minimum dispersal and broadcast of bottom material.
G. When dredging is permitted, the dredging shall be the minimum necessary to accommodate the proposed use and unavoidable impacts shall be mitigated.
H. Permit applications for shoreline dredging and dredge material disposal may be required to include the following information:
1. Physical, chemical, and biological assessment of the proposed dredged material applicable to the particular dredging site.
2. Specific data to be considered include:
a. Physical – grain size, clay, silt, sand, or gravel as determined by sieve analysis;
b. Chemical – including conventional parameters, metals, and organics;
c. Biological – bioassays to determine the suitability of dredged material for a selected disposal option;
d. Dredging volumes, methods, schedule, frequency, hours of operation and procedures;
e. Method of disposal, including the location, size, capacity, and physical characteristics of the disposal site, transportation method and routes, hours of operation, schedule;
f. Stability of bed lands adjacent to proposed dredging area;
g. Hydraulic analyses, including tidal fluctuation, current flows, direction and projected impacts. Hydraulic modeling studies are required for large scale, extensive dredging projects, in order to identify existing hydrological and geological patterns and probable effects of dredging;
h. Assessment of water quality impacts; and
i. Biological assessment including migratory, seasonal, and spawning use areas.
I. New development shall be located and designed to avoid or minimize the need for new or maintenance dredging where feasible.
J. Maintenance dredging of established navigation channels, public access facilities, and basins is restricted to maintaining previously dredged and/or existing authorized location, depth, and width.
K. Dredging of beds or shores of navigable waters owned by the state of Washington shall require prior authorization of the Washington Department of Natural Resources. (Ord. 2002 § 4 (Exh. B), 2019).
21.30.030 Shoreline stabilization (bulkheads and revetments).
A. New shoreline uses and developments shall be located away from the shoreline in order to preclude the need for new shoreline stabilization structures during the life of the structure, as demonstrated by a geotechnical analysis.
B. Shoreline Stabilization Alternatives Hierarchy. Structural shoreline stabilization measures should be used only when more natural, flexible, nonstructural methods such as vegetative stabilization, beach nourishment, and bioengineering have been determined infeasible. Alternatives for shoreline stabilization should be based on the following hierarchy of preference:
1. No action (allow the shoreline to retreat naturally), increase building setbacks, and relocate structures.
2. Flexible stabilization constructed of natural materials incorporating measures such as soft shore protection and bioengineering, including beach nourishment, protective berms, or vegetative stabilization.
3. Flexible stabilization, as described above, with rigid works, as described below, constructed as a protective measure at the buffer line.
4. A combination of rigid works, as described below, and flexible defense works, as described above.
5. Rigid works constructed of artificial materials such as riprap or concrete.
C. New or replacement structural stabilization measures shall not be allowed except when necessity is demonstrated in one of the following situations, and subject to the following conditions:
1. New or enlarged structural shoreline stabilization measures for an existing primary structure, including residences, should not be allowed unless there is conclusive evidence, documented by a geotechnical analysis, that:
a. An existing structure is in danger from shoreline erosion within three years, or where waiting until the need is immediate would prevent the opportunity to use measures that avoid impacts on ecological functions;
b. The structure cannot be feasibly relocated further from the land/water interface; or
c. Planting vegetation or installing on-site drainage improvements on the shoreline is not feasible or not sufficient;
d. Normal shoreline erosion itself, without a scientific or geotechnical analysis, is not demonstration of need;
2. The stabilization measure is evaluated by the hierarchy in subsection B of this section;
3. The stabilization measure will not result in a net loss of shoreline ecological functions.
4. The shoreline stabilization structures are limited to the minimum size necessary.
D. Existing shoreline stabilization structures not in compliance with this code may be retained, repaired, or replaced in accordance with the criteria below:
1. Normal maintenance and repair may be performed for a shoreline stabilization facility for a legally established land use; however, if substantial reconstruction of the stabilization structure is required or if the land use for which the shoreline stabilization structure was constructed is abandoned or replaced, the provisions for new structures in subsections A, B and C of this section shall apply.
2. Additions to or increases in size of existing shoreline stabilization measures shall be considered new structures.
E. Shoreline stabilization measures as part of projects for the restoration of ecological functions or hazardous substance remediation projects pursuant to Chapter 70.105D RCW may be approved when compliance with the following standards are documented by a geotechnical analysis:
1. The stabilization measures together with any compensatory mitigation proposed by the applicant and/or required by regulatory agencies will not result in a net loss of shoreline ecological functions.
2. The stabilization structure is evaluated by the hierarchy in subsection B of this section.
F. Groins, weirs and other in-water structures may be authorized only as part of a flood hazard control plan or for ecological restoration. A geotechnical analysis of stream geomorphology both upstream and downstream shall document that alternatives to in-water structures are not feasible. Documentation shall establish impacts on ecological functions that must be mitigated to achieve no net loss.
G. When any structural shoreline stabilization measures are demonstrated to be necessary, the following criteria shall apply:
1. Shoreline stabilization measures shall be designed by a qualified professional. Certification by the design professional may be required to ensure that installation meets all design parameters.
2. Shoreline stabilization measures shall be designed to be of the minimum size necessary.
3. Measures shall be incorporated into the design to assure no net loss of shoreline ecological functions.
H. Geotechnical analysis pursuant to this section shall contain the following:
1. The estimated time frames and rates of erosion related to the life span of the structures or facilities being protected;
2. An analysis of stream geomorphology both upstream and downstream shall assess the physical character and hydraulic energy potential of the specific stream reach and adjacent reaches upstream or down to assure that the physical integrity of the stream corridor is maintained, that stream processes are not adversely affected, and that the revetment will not cause significant damage to other properties or valuable shoreline resources; and
3. An assessment of aquatic and upland wildlife that may be affected by stabilization measures.
I. Restoration and/or public access shall be incorporated into the location, design, and maintenance of shoreline stabilization measures for public or quasi-public developments whenever safely compatible with the primary purpose. Shore stabilization on publicly owned shorelines should not be allowed to decrease long-term public use of the shoreline.
J. Soft shoreline stabilization measures that provide restoration of shoreline ecological functions may be permitted waterward of the OHWM. Replenishment of substrate materials to maintain the specifications of the permitted design may be allowed as normal maintenance. (Ord. 2002 § 4 (Exh. B), 2019).
21.30.040 Clearing and grading.
A. Clearing and grading activities shall only be allowed in association with an allowed (permitted) shoreline development.
B. Clearing and grading activities shall be limited to the minimum necessary for the intended development, including any clearing and grading approved as part of a landscape plan.
C. A temporary erosion and sediment control (TESC) plan shall be implemented that employs best management practices (BMPs) consistent with city design and construction standards.
D. Clearing and grading activities shall adhere to a prepared schedule and plan approved by the director and shall specify:
1. Limits of clearing and grading activities;
2. Design, implementation, maintenance, and monitoring of mitigation requirements to prevent erosion, siltation, and destruction of vegetation; and
3. Time period of grading which shall be completed or stabilized by October 31st of each year unless the applicant provides technical analysis that demonstrates to the satisfaction of the director that no harm to the shoreline environment would result from grading between October 31st and April 1st.
E. Clearing invasive shoreline vegetation listed on the King County Noxious Weed List is permitted in the shoreline, provided handheld equipment is used and native vegetation is promptly reestablished in the disturbed area. (Ord. 2002 § 4 (Exh. B), 2019).
21.30.050 Fill.
Fill placed waterward of the OHWM or within critical area buffers shall be prohibited except for specific, permitted, water-dependent uses or ecological restoration projects where there is no feasible alternative to accommodate the use, and shall be limited to the minimum necessary to provide for the proposal. (Ord. 2002 § 4 (Exh. B), 2019).
21.30.060 Ecological function and habitat enhancement.
A. An ecological function or habitat enhancement project shall be limited to areas in which past human activities have altered or degraded natural functions unless alteration of natural topography, vegetation, and other features is necessary as part of a larger enhancement program.
B. The area of an enhancement project shall be protected in perpetuity through a conservation easement or similar encumbrance conveyed to the city or other public agency unless owned by a public agency with a primary responsibility for natural resource protection.
C. A Model Toxic Control Act cleanup project shall restore a site to meet critical area buffers and other requirements of this code unless a particular approval for water-dependent use has been approved on the site.
D. Habitat improvements shall use an ecosystem or landscape approach to assure that plans are integrated into overall shoreline geomorphic and ecological functions. (Ord. 2002 § 4 (Exh. B), 2019).
21.30.070 In-stream structures.
A. In-stream structures shall be prohibited except as an essential element of a permitted water-dependent use or as an essential part of a flood hazard reduction program or ecological restoration project. In all cases it must be demonstrated that there are no feasible alternatives and the size shall be limited to the minimum necessary to provide for the required functions.
B. Where in-stream structures are permitted, they shall be developed and maintained in a manner that does not adversely impact ecological functions or fish and wildlife habitat.
C. Public access to and along the affected shoreline shall be provided in compliance with PMC 21.20.040.
D. Design, construction and maintenance shall comply with all relevant regulatory programs, including but not limited to the State Department of Fish and Wildlife, State Department of Ecology, and other relevant agencies.
E. Shoreline conditional use permit is required for all in-stream structures except those related to ecological enhancement. (Ord. 2002 § 4 (Exh. B), 2019).