Bellingham, WA Environmental Rules: Erosion Control (2026)

BMC Chapter 15.42 implements the construction-site control portion of Bellingham's Western Washington Phase II MS4 permit. Every construction site must install and maintain temporary erosion and sediment control (TESC) BMPs sized for the SWMMWW before ground disturbance begins. Typical required BMPs are silt fence at the down-gradient perimeter, stabilized construction entrances with rock pads, inlet protection on adjacent storm drains, concrete-washout containment, stockpile covers, and prompt seeding/mulching of disturbed areas. The state-permit threshold is identical to the rest of Washington: one acre or more of land disturbance (or a smaller site that is part of a larger common plan of development totaling at least one acre) must enroll in Ecology's Construction Stormwater General Permit, develop a SWPPP under the SWMMWW, and conduct routine inspections by a Certified Erosion and Sediment Control Lead (CESCL). Within the Lake Whatcom Reservoir watershed, BMC 16.80.120 imposes a seasonal restriction: ground-disturbing activities such as clearing vegetation, grading, filling, or exposing soils are only permitted from June 1 to September 30 each year. All exposed soil must be covered by October 1 with mulch, rock, straw, or established vegetation. This protects the city's drinking-water reservoir from sediment and phosphorus mobilization during the heavy fall and winter rains characteristic of the Pacific Northwest climate. Sediment-laden runoff that reaches Whatcom Creek, Squalicum Creek, Padden Creek, Chuckanut Creek, Bellingham Bay or Lake Whatcom violates the receiving-water protections of BMC 15.42 and WAC 173-201A.