Skip to main content
This section is included in your selections.

Dredging is defined in SCC 30.91D.445.

(1) The following general regulations apply to dredging and dredge spoil disposal within shorelines:

(a) Projects shall be sited and designed to avoid the need for new or maintenance dredging.

(b) Dredging and dredge spoil disposal are allowed only:

(i) For maintenance of existing navigation channels, provided that the dredging extent is limited to that area previously dredged or to the authorized location, depth and width;

(ii) When necessary to construct or maintain marinas, boat ramps or other boat launch facilities;

(iii) For flood protection under SCC 30.67.540;

(iv) In conjunction with ecological restoration or enhancement projects;

(v) In conjunction with mining activities allowed pursuant to SCC 30.67.560(1)(a); or

(vi) When necessary to maintain and operate public water supply, power generation, and flood control reservoirs, including, but not limited to, sediment removal at pipe inlets or outlets.

(c) The operation and location of dredging and dredge disposal sites shall meet the following criteria:

(i) Unless directly related to restoration or enhancement of shoreline ecological functions, dredging shall not be allowed:

(A) Within critical saltwater habitats or salmonid spawning areas; or

(B) For the sole purpose of obtaining fill or mineral resources except as allowed pursuant to 30.67.530(1)(b);

(ii) Dredging and dredge material disposal activities shall implement all feasible mitigation measures to minimize adverse impacts to shoreline habitats;

(iii) Dredging projects that convert intertidal habitat to subtidal habitat in order to improve navigability must include a comprehensive assessment identifying potential cumulative impacts of site-specific changes to ecosystem functions;

(iv) Dredging shall not be allowed along net-positive drift sectors and where geohydraulic processes are active and accretion shoreforms would be damaged, altered, or irretrievably lost;

(v) Unless in conjunction with an ecological restoration project, open water dredge disposal shall occur only at approved Puget Sound Dredge Disposal Analysis (PSDDA) sites. Any party utilizing a PSDDA site must comply with all PSDDA requirements; and

(vi) Cleanup and disposal of dredged material waterward of the ordinary high water mark must be in accordance with a state Department of Natural Resources Dredged Material Management Program.

(d) Dredge spoils may be utilized in ecological restoration or enhancement projects, provided that they do not contain contaminants and water quality is not adversely impacted.

(e) All dredge spoil disposal sites, except for PSDDA sites, shall meet the following requirements:

(i) The disposal site shall be located outside of the channel migration zone unless the dredge materials will be for a permitted use within the adjacent shoreline jurisdiction;

(ii) Before beginning disposal operations, the dikes enclosing the disposal site shall be constructed such that no spoils bearing discharge water may escape. The disposal site dikes shall be kept in this condition throughout any disposal operation;

(iii) The settling area within the dikes must be large enough so that the outlet pipe conveying return water can be periodically relocated to control the uptake of suspended sediment;

(iv) Normal drainage patterns within the project site shall not be adversely affected by the spoils disposal operation;

(v) Within six months of the issuance of a permit for dredging activities, trees shall be planted and maintained around the perimeter of the site to act as a visual buffer;

(vi) Dredge spoils may be deposited and removed from the site in a manner that does not disturb the perimeter dike, except at points of ingress and egress, and consistent with the conditions of the approved permit; and

(vii) Written notice shall be given to the department at least two weeks prior to the commencement of any permitted dredge spoils disposal operation.

(2) In addition to the general regulations contained in SCC 30.67.530(1), the following shoreline environment designation-specific regulations for dredging and dredge spoil disposal apply:

(a) Dredging and dredge spoil disposal is conditionally permitted in all shoreline environments when directly related to restoration or enhancement of shoreline ecological functions.

(b) For all dredging or dredge spoil disposal projects not related to ecological enhancement or restoration projects, the following shoreline environment designation-specific regulations apply:

(i) Dredge spoil disposal is conditionally permitted in the Urban, Rural Conservancy and Resource environments;

(ii) Dredge spoil disposal is prohibited in the Urban Conservancy and Natural environments;

(iii) Dredging and dredge spoil disposal are conditionally permitted in the Municipal Watershed Utility environment when consistent with a project license issued by the Federal Energy Regulatory Commission;

(iv) Dredging in the Aquatic environment is conditionally permitted when allowed pursuant to SCC 30.67.530(1); and

(v) Dredge spoil disposal is conditionally permitted in the Aquatic environment when:

(A) The dredge spoil disposal is conducted in conjunction with any of the following project types:

(I) Cleanup and disposal of contaminated sediments as part of an interagency environmental clean-up plan;

(II) Disposal of dredged material from dredging projects allowed under SCC 30.67.530(1)(b) when the dredged material is considered suitable under, and conducted in accordance with, the dredged material management program of the state Department of Natural Resources; or

(III) Disposal of dredged material in conjunction with an approved ecological restoration or enhancement project; or

(B) The dredge spoils are deposited at a Puget Sound Dredge Disposal Analysis (PSDDA) site. (Added by Amended Ord. 12-025, June 6, 2012, Eff date July 27, 2012).