Shoreline, WA Environmental Rules: Erosion Control (2026)

SMC § 20.50.340(A) applies erosion and sediment control (ESC) to any activity that clears, grades or otherwise disturbs a Shoreline site, whether it needs a clearing or grading permit or not, and ties the temporary ESC measures to the performance criteria in SMC § 13.10.200, the City's Surface Water Management Code. Cuts and fills approved by the Director may not exceed a slope steeper than two horizontal to one vertical under SMC § 20.50.340(B)(1), and disturbed cut and fill faces must be prepared and maintained to control erosion consistent with the Surface Water Design Manual under subsection (B)(2).

Fill material cannot include detrimental organic material or rock larger than 12 inches in maximum dimension, and drainage provisions must prevent surface water or seepage from damaging cut or fill faces and must carry concentrated runoff to a natural watercourse or another method approved by Public Works. Required benches must be at least 10 feet wide, back-sloped, spaced no more than 25 feet vertically, with swale gradients capped at five percent. The Director can require access-road gates, warning signs and temporary fencing on active grading sites.

Work hours for tree cutting, clearing and grading are limited to 7:00 a.m. to 7:00 p.m. on weekdays and 9:00 a.m. to 9:00 p.m. on Saturdays and Sundays under subsection (G), with felling restricted to daylight hours, and haul-route traffic control plans are required under subsection (H).