Richland, WA Environmental Rules: Erosion Control (2026)

Chapter 16.06 of the Richland Municipal Code governs construction and post-construction stormwater. RMC § 16.06.020 applies the chapter to all construction and land development meeting at least one of three tests: disturbance of one acre or more, any project the Public Works Director identifies as likely to generate contaminated runoff regardless of size, or smaller phases of a larger common plan of development, including single-family lots within a platted subdivision. Forest practices under WAC Title 222, ordinary commercial agriculture, oil and gas field work, and routine road and parking maintenance such as pothole patching, crack sealing and shoulder grading are exempt.

Under RMC § 16.06.030, covered projects must comply with the City of Richland Standard Design Guidelines and Construction Details and the Stormwater Management Manual for Eastern Washington, and must submit a stormwater pollution prevention plan (SWPPP) addressing erosion and sediment control BMPs. Every project must retain runoff generated on site for at least the 25-year, 24-hour rainfall event. Operators disturbing less than five acres, who are not part of a larger development, can qualify for reduced submittal and inspection requirements by obtaining an erosivity waiver from the Department of Ecology and certifying they will implement BMPs in compliance with city standards.

Utility agencies and their contractors must also implement BMPs preventing sediment release from utility trenching and construction sites. Before final acceptance, RMC § 16.06.040 requires record drawings of any permanent BMPs and a final city inspection, and § 16.06.050 makes the property owner responsible for ongoing operation and maintenance of permanent private stormwater facilities under a written O&M plan that transfers with the property.