Gravel removal 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 gravel removal projects:
(1) Gravel removal from a watercourse shall be limited to removal from exposed bars and shall not result in a lowering, over time, of the average channel cross-section profile through the project area or downstream. Additional removal of bed material, including removal from wetted portions of the channel, may be authorized where the project is an integral part of a comprehensive flood control plan approved by the department.
(2) An "excavation line" shall be established. "Excavation line" means a line on the dry bed, at or parallel to the water's edge, the distance from the water's edge to be determined by the department on a site-specific basis. The excavation line may change with water level fluctuations.
(3) An "excavation zone" shall be defined as the area between the "excavation line" and the bank or the center of the bar. The "excavation zone" shall be identified by boundary markers placed by the applicant and approved by the department prior to the commencement of gravel removal.
(4) Excavation shall begin at the excavation line and proceed toward the bank or the center of the bar, perpendicular to the alignment of the watercourse.
(5) Bed material shall not be removed from the water side of the excavation line.
(6) Equipment shall not enter or operate within the wetted perimeter of the watercourse.
(7) Gravel may be removed within the excavation zone from a point beginning at the excavation line and progressing upward toward the bank or the center of the bar on a minimum two percent gradient. It may be necessary to survey the excavation zone upon completion of the gravel removal operation to ensure the two percent gradient is maintained and that no depressions exist. When required the survey shall be made at the applicant's expense.
(8) Preproject and postproject channel cross-section surveys shall be required for gravel removal projects for commercial purposes, and may be required as part of a comprehensive flood control plan approved by the department. The cross-sections shall be referenced vertically to a permanent bench mark and horizontally to a permanent base line, and shall be done perpendicular to the high flow channel every one hundred feet through the project area and at cross-sections upstream and downstream at adjacent channel riffles. The preproject survey information shall be submitted to the department at the time of application for HPA, and the postproject survey shall be submitted to the department within ninety days of completion of removal of gravel or the expiration date of the HPA, whichever occurs first.
(9) At the end of each work day the excavation zone shall not contain pits, or potholes, or depressions that may trap fish as a result of fluctuation in water levels.
(10) Stockpiling of material waterward of the ordinary high water line, after the initial bed disturbance, shall be limited to avoid impacts to fish life. If stockpiling is approved waterward of the ordinary high water line, the material shall be completely removed prior to the onset of fish spawning in the vicinity or the typical onset of increasing stream flows. Timing restrictions shall be determined on a site-specific basis. If the water level rises and makes contact with stockpiles, further operation of equipment or removal of the stockpiles shall not proceed unless authorized under a separate HPA issued by the department.
(11) The upstream end of the gravel bar shall be left undisturbed to maintain watercourse stability waterward of the ordinary high water line.
(12) Large woody material shall be retained waterward of the ordinary high water line and repositioned within the watercourse. Other debris shall be disposed of so as not to reenter the watercourse.
(13) Gravel washing or crushing operations shall not take place waterward of the ordinary high water line.
(14) Alteration or disturbance of the banks and bank vegetation shall be limited to that necessary to access the excavation zone. All disturbed areas shall be protected from erosion, within seven days of completion of the project, using vegetation or other means. The banks shall be revegetated within one year with native or other approved woody species. Vegetative cuttings shall be planted at a maximum interval of three feet (on center), and maintained as necessary for three years to ensure eighty percent survival. Where proposed, planting densities and maintenance requirements for rooted stock will be determined on a site-specific basis. The requirement to plant woody vegetation may be waived for areas where the potential for natural revegetation is adequate, or where other engineering or safety factors preclude them.
(15) Equipment shall be inspected, cleaned, and maintained to prevent loss of petroleum products waterward of the ordinary high water line.
(16) The department shall be notified at least five working days before the start of actual gravel removal, and upon project completion to allow for compliance inspection.
[Statutory Authority: RCW 75.08.080
. WSR 94-23-058 (Order 94-160), § 220-110-140, filed 11/14/94, effective 12/15/94; WSR 87-15-086 (Order 87-48), § 220-110-140, filed 7/20/87. Statutory Authority: RCW 75.20.100
and 75.08.080. WSR 83-09-019 (Order 83-25), § 220-110-140, filed 4/13/83.]