SR-128 Rockslide Repair DO (EA 4X570)
Summary
SCH Number
2026010690
Public Agency
California Department of Transportation, District 4
(DOT)
Document Title
SR-128 Rockslide Repair DO (EA 4X570)
Document Type
NOE - Notice of Exemption
Received
Posted
1/22/2026
Document Description
Caltrans proposes repairing a rockslide that occurred on SR-128 in Sonoma County at PM 4.859. Severe winter storms caused rockfalls and slip outs due to oversaturation of the slope above the highway. Given the site conditions and continuing slope movement, immediate repair of the slope is necessary before the upcoming winter storm season causes further failure. Two landslide occurred at this location. The first occurred along the eastbound embankment slope and can be described as a shallow cut slope failure that is approximately 70 feet wide by 50 feet long by 3 feet deep. The second is also along the eastbound embankment slope and can be described as a shallow cut slope failure that is approximately 200 feet wide by 50 feet long by 3 feet deep. The Caltrans Office of Geotechnical Design recommends installing an anchored Double Twisted Wire Mesh (DTWM) system to control rockfall at the site. This system will be designed to hold rockfall in place on the slope since there is little to no catchment at the base of the slope. Prior to the installation of the anchored DTWM, the loose material on the slope shall be removed and the brow of the slope shall be graded to match adjacent slopes. Slide materials will be temporarily stockpiled in nearby vehicle pullout areas and will be hauled off and disposed or at a nearby facility. The existing ditch line will also be re-established. Traffic control will be required during construction, as well as construction area signs, portable message signs, and temporary k-rials.
Contact Information
Name
Juliane Smith
Agency Name
Caltrans
Job Title
Senior Environmental Scientist (NEPA/CEQA Specialist)
Contact Types
Lead/Public Agency / Project Applicant / Parties Undertaking Project
Address
Phone
Email
Location
Cities
Cloverdale
Counties
Sonoma
Regions
Northern California, San Francisco Bay Area
State Highways
SR-128
Other Location Info
The project is located on State Route (SR-) 128 in Sonoma County at post mile (PM) 4.859, 0.2 mile south of the intersection between SR-128 and North Cloverdale Boulevard in Cloverdale.
Notice of Exemption
Exempt Status
Categorical Exemption
Type, Section or Code
PRC 21084; 14 CCR 15301 Class 1
Reasons for Exemption
Class 1 Existing Facilities. The project is not anticipated to result in any environmental impacts. The project contains a number of standardized project measures which are employed on most, if not all, Caltrans projects and were not developed in response to any specific environmental impacts resulting from the project.
County Clerk
Sonoma
Attachments
Notice of Exemption
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