Dredging projects shall incorporate mitigation measures as necessary to achieve no-net-loss of productive capacity of fish and shellfish habitat. The following technical provisions shall apply to dredging projects:
(1) Dredging shall not be conducted in fish spawning areas unless it is designed to create or improve the access or quality of fish spawning areas.
(2) During the dredging of a lake or pond, a boom or similar device may be required to contain floatable materials.
(3) Dredged bed materials shall be disposed of at approved in-water disposal sites or upland so as not to reenter state waters. The department may allow placement of dredged material in areas for beneficial uses such as beach nourishment or capping of contaminated sediments.
(4) Dredging shall be conducted with dredge types and methods that cause the least adverse impact to fish and shellfish and their habitat.
(5) If at any time, fish are observed in distress, a fish kill occurs, or water quality problems develop as a result of dredging, operations shall cease immediately and the department shall be immediately contacted.
(6) An hydraulic dredge shall only be operated with the intake at or below the surface of the material being removed. The intake shall only be raised a maximum of three feet above the bed for brief periods of purging or flushing the intake system.
(7) If a dragline or clamshell is used, it shall be operated to minimize turbidity. During excavation, each pass with the clamshell or dragline bucket shall be complete. Dredged material shall not be stockpiled waterward of the ordinary high water line.
(8) Upon completion of the dredging, the bed shall not contain pits, potholes, or large depressions to avoid stranding of fish.
[Statutory Authority: RCW 75.08.080
. WSR 94-23-058 (Order 94-160), § 220-110-130, filed 11/14/94, effective 12/15/94. Statutory Authority: RCW 75.20.100
and 75.08.080. WSR 83-09-019 (Order 83-25), § 220-110-130, filed 4/13/83.]