HWY 1 Valley Ford Slipout Repair DO (EA 0V500)
Summary
SCH Number
2026050107
Public Agency
California Department of Transportation, District 4
(DOT)
Document Title
HWY 1 Valley Ford Slipout Repair DO (EA 0V500)
Document Type
NOE - Notice of Exemption
Received
Posted
5/5/2026
Document Description
The California Department of Transportation (Caltrans) proposed repairing a slipout that occurred on Highway 1 at post mile (PM) 4.1 in Sonoma County, north of Valley Ford. The slipout was caused by a series of rain events that occurred this winter. A section of the existing culvert had been displaced due to a failed joint, allowing the stormwaters to cause the slipout. The dimensions of the slipout are approximately 30 feet wide by 30 feet deep, with the edge of failure (hinge point) located about 4 feet from the edge of traveled way. The slipout caused the pipe to lose its support which resulted in pipe separation at the outlet end. Field Maintenance crews promptly installed sandbags to divert flow to prevent further erosion. Additionally, safety cones were placed to ensure the safety of the area. Delaying or not completing the permanent emergency repairs would increase the risk of continued embankment failure, potentially leading to an emergency highway closure if the condition is deemed an imminent threat.
The project will first clear and grub vegetation, debris, and loose material from the eroded slope. The slope will then be excavated a minimum of one foot into relatively firm material followed by lining the excavations with Class 8 rock slope protection (RSP) mixed with on-site native soil to match existing grade. Native soil from the failed area that was excavated can be used to fill voids underneath the roadway shoulder and the edge of pavement.
The project will then remove the separated 24-inch Reinforced Concrete Pipe (RCP) culvert in two segments about 3-feet each, and replace it at the joint separation with a new 24-inch RCP culvert. An RSP energy dissipation pad about 8-feet by 10-feet will be placed at the outfall to prevent future erosion of the south-facing slope below HWY-1.
Temporary traffic control will be required during construction activities.
Silt fence and fiber rolls will be installed around the work area as sediment and erosion control.
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
Unincorporated Sonoma County
Counties
Sonoma
Regions
Northern California, San Francisco Bay Area
State Highways
1
Other Location Info
The project is located on Highway 1 at post mile (PM) 4.1 in Sonoma County, north of Valley Ford.
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
Disclaimer: The Governor’s Office of Land Use and Climate Innovation (LCI) accepts no responsibility for the content or accessibility of these documents. To obtain an attachment in a different format, please contact the lead agency at the contact information listed above. For more information, please visit LCI’s Accessibility Site.