Yakima, WA Environmental Rules: Erosion Control (2026)

YMC Chapter 7.82 implements the construction-site control portion of Yakima's Eastern Washington Phase II MS4 permit. Every construction site must install and maintain temporary erosion and sediment control (TESC) BMPs sized for the local soils, slope, and runoff before ground disturbance begins. Required BMPs are drawn from the Stormwater Management Manual for Eastern Washington (SWMMEW) and typically include silt fence at the down-gradient perimeter, stabilized construction entrances with rock pads, inlet protection on adjacent storm drains and drywells, dust control (an especially live issue in semi-arid Yakima), concrete-washout containment, stockpile covers, and prompt seeding/mulching of disturbed areas. The state-permit threshold is the same as elsewhere in 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 SWMMEW, and conduct routine inspections by a Certified Erosion and Sediment Control Lead (CESCL) for sites of one acre or more. Smaller sites still must apply source-control BMPs under the city's authority through YMC 7.82, and any site that discharges sediment to the MS4 or to waters of the state can be cited regardless of acreage. The Yakima River and Naches River are 303(d)-listed for turbidity, so sediment release receives heightened scrutiny. Compliance is reviewed by the city's Surface Water Engineer and inspectors during normal building-permit inspections.