13.11.060 Dredging and dredge material disposal

13.11.060 Dredging and dredge material disposal.

1. New development shall be designed and located to avoid or, if infeasible, to minimize the need for new and maintenance dredging.

2. Dredging shall be allowed only for one or more of the following purposes:

a. For shoreline restoration projects benefiting water quality and/or fish and wildlife habitat.

b. For flood hazard reduction, when performed as part of an approved flood hazard reduction plan, such as King County’s flood hazard management plan or Snohomish County’s surface water management plan.

c. To maintain existing legal moorage facilities.

d. To maintain existing navigation or navigation access.

e. In conjunction with a bridge or navigational structure for which there is a public need and where other feasible sites or routes do not exist.

3. Developments which propose dredging for the primary purpose of obtaining fill material are prohibited, except when the material is necessary for the restoration of ecological functions and is placed waterward of the OHWM. Such an application shall be associated with a Model Toxics Control Act (MTCA) or Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) habitat restoration project or, if approved through a shoreline conditional use permit, another significant habitat enhancement project.

4. Dredging to maintain an existing legal navigation route shall be restricted to restoring the previously authorized location, depth, and width of the navigation channel.

5. Dredging and dredge material disposal shall be permitted only where it is demonstrated that the proposed dredging or deposition shall not:

a. Result in significant or ongoing damage to water quality, fish, and shoreline wildlife habitat;

b. Alter natural drainage and water circulation patterns, currents, river flows, and channel migration processes or significantly reduce flood water capacities; or

c. Cause other significant adverse ecological impacts.

6. Proposals for dredging and dredge material disposal shall, when impacts cannot be avoided, minimize and mitigate adverse impacts (such as turbidity; release of nutrients, heavy metals, sulfides, organic material or toxic substances; dissolved oxygen depletion; disruption of food chains; loss of benthic productivity; and disturbance of fish runs and important localized biological communities) to assure no net loss of shoreline ecological functions. Mitigation plans shall be prepared by a qualified professional.

7. Dredging and dredge material disposal shall be carefully scheduled to protect biological productivity (e.g., fish runs, spawning, benthic productivity).

8. When dredging is permitted, the dredging shall be the minimum necessary to accomplish its intended purpose.

9. Dredging shall utilize techniques that cause minimum dispersal and broadcast of bottom material.

10. Vegetation disturbed by dredging activities shall be restored to its original condition, equal alternative, or an improved condition. All replacement vegetation shall be native species.

11. Dredging and dredge material disposal shall be prohibited on or in archaeological sites that are listed on the Washington State Register of Historic Places until such time that they have been released by the State Archaeologist.

1. Upland 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 groundwater; and

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

c. The site will ultimately be suitable for a use allowed by this SMP.

2. Dredge material disposal shall not occur on shorelands or in wetlands within a stream’s channel migration zone, except as authorized by conditional use permit as part of a shoreline restoration project.

3. Dredge material disposal within areas assigned an aquatic environment designation may be approved only when authorized by applicable agencies, which may include the U.S. Army Corps of Engineers pursuant to Section 10 (Rivers and Harbors Act) and Section 404 (Clean Water Act) permits, and Washington State Department of Fish and Wildlife hydraulic project approval (HPA); and when one of the following conditions apply:

a. Land disposal is infeasible, less consistent with this SMP, or prohibited by law; or

b. Disposal as part of a program to restore or enhance shoreline ecological functions and processes is not feasible.

4. Dredge materials approved for disposal within Bothell’s shoreline areas assigned an aquatic environment designation shall comply with the following conditions:

a. Aquatic habitat will be protected, restored, or enhanced;

b. Adverse effects on water quality or biologic resources from contaminated materials will be mitigated;

c. Shifting and dispersal of dredge material will be minimal; and

d. Water quality will not be adversely affected.

5. When required by the city’s shoreline administrator, revegetation of land disposal sites shall occur as soon as feasible in order to retard wind and water erosion and to restore the wildlife habitat value of the site. Native species shall be used in the revegetation.

6. Dredge material disposal operating periods and hours shall be limited to those stipulated by the Washington State Department of Fish and Wildlife and hours to 7:00 a.m. to 5:00 p.m. Monday through Friday, except in time of emergency as authorized by the shoreline administrator. Provisions for buffers at land disposal or transfer sites in order to protect public safety and other lawful interests and to avoid adverse impacts shall be required.

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

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

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

a. A site plan map outlining the perimeter of the proposed dredge area. The map must also include the existing bathymetry (water depths that indicate the topography of areas below the OHWM) and have data points at a minimum of two-foot depth increments.

b. A critical areas special study.

c. A mitigation plan if necessary to address any identified adverse impacts to ecological functions or processes.

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

3. If additional data on the physical, chemical or biological characteristics of the dredge materials to be removed is required by any state or federal agency, such data shall be provided to the city.

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

5. Dredging procedure, including the length of time it will take to complete dredging, method of dredging, and amount of materials removed.

6. Frequency and quantity of project maintenance dredging.

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

a. Dredge material disposal area;

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

c. Size and capacity of disposal site;

d. Means of transportation to the disposal site;

e. Proposed dewatering and stabilization of dredged material;

f. Methods of controlling erosion and sedimentation; and

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

8. Total estimated initial dredge volume.

9. Plan for disposal of maintenance spoils for at least a 20-year period, if applicable.

10. Hydraulic modeling studies sufficient to identify existing geohydraulic patterns and probable effects of dredging. (Ord. 2112 § 3 (Exh. C), 2013).