A. Shoreline stabilization shall be designed and constructed to avoid adverse impacts affecting downstream banks.
B. New shoreline stabilization shall not preclude river channel migration within the floodway.
C. Shoreline stabilization shall be designed and constructed consistent with the critical areas report required by SMC 14.250.330(A)(5). Where possible, shoreline vegetation shall be preserved.
D. In addition to the required permit application materials required by other sections of this title, the applicant shall provide the following materials under the stamp of a qualified professional engineer:
1. Description of project’s purpose and scope.
2. Description of the hydraulic characteristics of the water body within one-half (1/2) mile of the proposed project, before and after the stabilization/protection project.
3. Description of existing shoreline stabilization within one-half (1/2) mile of the proposed project.
4. Proposed construction materials and methods.
E. Using studies by qualified professionals, including a geotechnical analysis and a field determination of the ordinary high water mark done no more than one (1) year before submittal of a complete application, the applicant shall demonstrate the following:
1. That the structure is in danger from shoreline erosion from tidal action, waves or currents, including a description of the damage or loss that is expected to occur if stabilization is not provided, and a timeframe within which such damage or loss is anticipated to occur.
2. Erosion is not caused by upland conditions on the project site that, if corrected, would eliminate the need for shoreline stabilization;
3. The proposal is the minimum necessary to protect existing legally established structures; existing water-dependent development; or achieve restoration of ecological functions.
4. Except for the protection of the shoreline requiring stabilization, the effect on natural fluvial, hydrological, and geomorphological processes will be minimized.
5. Mitigation measures will maintain or augment shoreline processes and critical fish and wildlife habitat so that no net loss of function of riparian habitat will occur.
6. Shoreline stabilization shall minimize the adverse impact to other properties to the maximum extent practical.
7. Shoreline stabilization shall not interfere with surface or subsurface drainage into the water body or to or from wetlands.
F. Replacement of an existing shoreline stabilization structure that can no longer adequately serve its purpose may be permitted without a determination of imminent need subject to the following:
1. The replacement structure shall be designed, located, sized, and constructed to ensure no net loss of ecological functions;
2. Replacement of walls or solid bulkheads shall not encroach waterward of the OHWM or existing structure unless protecting a residence that was occupied prior to January 1, 1992, and there are overriding safety or environmental concerns. In such cases, the replacement structure shall abut the existing shoreline stabilization structure;
3. Where stabilization would extend waterward of the OHWM, distance shall be the minimum necessary to preserve the stabilization function.
G. New hardened shoreline stabilization shall not be permitted unless the analysis confirms that there is a significant possibility that the upland structure will be damaged within three (3) years in the absence of hardened stabilization measures; or unless the analysis confirms that waiting until the need is immediate will foreclose on the opportunity to use measures that avoid impacts on ecological functions.
H. Shoreline stabilization shall not be used to create new shoreland area.
I. Material that may release hazardous substances shall not be used for shoreline stabilization.
J. Shoreline stabilization shall be designed so as not to constitute a hazard to navigation.
K. Shoreline stabilization shall be designed so as not to create a need for shoreline stabilization elsewhere.
L. Shoreline stabilization measures shall not be allowed within any designated floodway except as may be necessary to protect existing development or prevent serious impairment of channel function.
M. Shoreline stabilization measures shall be consistent with the Integrated Stream Protection Guidelines (Washington Departments of Fish and Wildlife, Ecology, and Transportation, 2003).