Erosion Control: Rohnert Park vs Sonoma

Do I need a grading permit for a small project in Sonoma County?

Yes, in most cases. Sonoma County Code Section 11.04.010 requires a construction grading permit before any grading, land clearing, vegetation removal, or other ground disturbance not explicitly exempted (a few low-volume residential exemptions exist - confirm with Permit Sonoma). The GRD-011 ESCP Notes set the standard BMPs.

When does Sonoma County's wet-season erosion-control rule apply?

October 15 through May 15. During that window, no more than 1 acre or 20% of the permitted work area (whichever is greater) may have erodible soil exposed at any time, and BMPs must be functional at all times. Outside the wet season, BMPs are required whenever NWS forecasts 30% or greater rain within 24 hours.

What is VESCO and does it apply to my vineyard project?

VESCO is the Vineyard and Orchard Site Development Ordinance in Chapter 36 of the Sonoma County Code. Any new vineyard or orchard on slopes 10-50% requires a VESCO erosion-control plan with stream setbacks (25-200 ft depending on stream class), and slopes over 50% are generally prohibited from new vineyard or orchard development.

Does a small homeowner grading project need an erosion plan?

Yes — SMC 14.20.205 requires an erosion and sediment control plan as part of every grading permit application, regardless of size. The level of detail and required professional certification scale with project complexity and site sensitivity.

What happens if my erosion controls fail during a winter storm?

The City Engineer may issue a stop-work order under SMC 14.20 and require immediate corrective action. Sediment-laden discharges to a storm drain or creek can also trigger NPDES enforcement under SMC 13.32 and state Water Code §13385.