SON-128 Slope Failure Repair DDO (EA 4X040)

Caltrans District 4 is forecasting a project to repair a slope failure located at 2560 Highway 128 in Sonoma County, specifically on westbound SR-128 east of Geyserville at post mile 7.63. The failure, which measures approximately 30 feet wide and 12 feet high, was caused by overly saturated soil and a suspected drainage failure or spring on the private property above the highway. To stabilize the embankment and prevent further erosion, the project will utilize Class VI, 3/8 ton Rock Slope Protection (RSP) Type A Placement over RSP fabric, with rock voids filled using native or imported borrow materials and excavated soil. The scope of work also includes the reestablishment of a natural drainage ditch for a total length of 50 feet, extending 10 feet easterly and westerly from the failed area to conform to the existing ditch. Traffic control will be required throughout the construction process. This project is categorized as a forecast under NAICS code 237310 and is considered categorically exempt under PRC 21084 and 14 CCR 15301 Class 1(d), as it involves the repair of existing facilities with no anticipated environmental impacts.