15.14.380 Dredging and dredge material disposal

15.14.380 Dredging and dredge material disposal.

For the purposes of this section, dredging shall refer to the excavation or displacement of land waterward of the ordinary high-water mark.

1. Dredging should be permitted for water-dependent uses and/or essential public facilities only when necessary and when alternatives are infeasible.

2. Dredging of bottom materials for the primary purpose of obtaining material for landfill, construction, or beach nourishment should not be permitted.

3. Minor dredging as part of ecological restoration or enhancement, public access or public recreation should be permitted if consistent with this SMP.

4. Spoil disposal on land outside of shoreline jurisdiction is generally preferred over disposal below the ordinary high-water mark. Disposal of dredged material on shorelands or wetlands within the stream’s channel migration zone should be discouraged.

5. Long-term cooperative management programs that rely primarily on natural processes and involve land owners and applicable local, state and federal agencies and tribes should be pursued to prevent or minimize conditions which make dredging necessary.

6. New development should be sited and designed to avoid or, where avoidance is not possible, to minimize the need for new maintenance dredging.

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

1. Siting and Design. New development shall be sited and designed to avoid the need for new and maintenance dredging.

2. Allowed Dredging Activities. Dredging shall only be permitted for the following activities:

a. Development of new or expanded essential public facilities and only when there are no feasible alternatives or other alternatives that may have a lesser ecological impact.

b. Restoration or enhancement of shoreline ecological functions and processes benefiting water quality and/or fish and wildlife habitat. Dredging activity to drain wetlands shall not be allowed. Dredged material shall be placed waterward of the ordinary high-water mark. Dredging projects for the purpose of restoration must either be associated with a MTCA or CERCLA habitat restoration project or otherwise must obtain a shoreline conditional use permit.

c. Dredging of Contaminated Sediments Associated with an Approved Hazardous Waste Remediation Project. Contaminated spoils shall be disposed of in an upland facility authorized to accept hazardous materials.

d. Minor trenching to allow the installation or maintenance of necessary underground utilities if no alternative, including boring, is feasible, and:

i. Impacts to fish and wildlife habitat are avoided to the maximum extent possible;

ii. The utility installation shall not increase or decrease the natural rate, extent, or opportunity of channel migration;

iii. Appropriate best management practices are employed to prevent water quality impacts or other environmental degradation.

e. Dredging for the purpose of obtaining fill material is prohibited.

f. Dredging activity to drain wetlands shall not be allowed.

3. Conditional Use Permit. A conditional use permit shall be required for any project involving the disposal of dredge material in the stream of a channel migration zone.

4. Maintain Ecological Functions and Processes. The physical alignment and ecological functions and processes of shoreline waterbodies shall be maintained, except to improve hydraulic function, water quality, fish or wildlife habitat, or fish passage.

5. Conditions May Be Applied. Limitations on dredge or disposal operation may be imposed to reduce proximity impacts, protect the public safety and assure compatibility with the interests of other shoreline users. Conditions may include limits on periods and hours of operation, type of machinery, and may require provision of landscaped buffer strips and/or fencing to address noise and visual impacts at land disposal or transfer sites.

6. Circumstances When Disposal Is Allowed. Dredge material disposal within shoreline jurisdiction is permitted under the following conditions:

a. Shoreline ecological functions and processes will be preserved, restored or enhanced, including protection of surface and ground water.

b. Erosion, sedimentation, floodwaters or runoff will not increase adverse impacts to shoreline ecological functions and processes or property.

7. Submittal Requirements. The following information shall be required for all dredging applications:

a. A description of the purpose of the proposed dredging and an analysis of compliance with the policies and regulations of this SMP.

b. A detailed description of the existing physical character, shoreline geomorphology and biological resources provided by the area proposed to be dredged, including:

i. A site plan map outlining the perimeter of the proposed dredge area. The map must also include the existing bathymetry and have data points at a minimum of two-foot depth increments;

ii. A habitat survey, critical areas study, fish and wildlife management plan during dredging operations, and/or mitigation plans;

iii. Information on stability of bedlands adjacent to proposed dredging and spoils disposal areas.

c. If disposal of dredge materials is proposed below the ordinary high-water mark, a detailed description of the physical, chemical and biological characteristics of the dredge materials to be removed.

i. Physical analysis of material to be dredged: material composition and amount, grain size, organic materials present, source of material, etc.;

ii. Chemical analysis of material to be dredged: volatile solids, chemical oxygen demand (COD), grease and oil content, mercury, lead and zinc content, etc.;

iii. Biological analysis of material to be dredged.

d. A description of the method of materials removal, including facilities for settlement and movement.

e. Dredging procedure: length of time it will take to complete dredging, method of dredging, and amount of materials removed.

f. Frequency (including an estimate of the effective life expectancy of the dredging) and quantity of project maintenance dredging.

g. Detailed plans for dredge spoil disposal, including specific land disposal sites and relevant information on the disposal site, including, but not limited to:

i. Dredge material disposal area;

ii. Physical characteristics including location, topography, existing drainage patterns, surface and ground water;

iii. Size and capacity of disposal site;

iv. Means of transportation to the disposal site;

v. Proposed dewatering and stabilization of dredged material;

vi. Methods of controlling erosion and sedimentation; and

vii. Future use of the site and conformance with land use policies and regulations.

h. Total initial dredge volume.

i. Plan for disposal of maintenance spoils for at least a 50-year period, if applicable.

j. Hydraulic modeling studies sufficient to identify existing geo-hydraulic patterns and probable effects of dredging. [Res. 2023-04 § 1 (Att. B), 2023; Ord. 580 Att. A § 5.4, 2019.]