SR-128 Pavement Settlement and Drainage Repair DO (EA 04-0V830)
Summary
SCH Number
2026071038
Public Agency
California Department of Transportation, District 4
(DOT)
Document Title
SR-128 Pavement Settlement and Drainage Repair DO (EA 04-0V830)
Document Type
NOE - Notice of Exemption
Received
Posted
7/27/2026
Document Description
The California Department of Transportation (Caltrans) proposes repairing pavement settlement and drainage failures at post mile (PM) 16.07 and 16.16 on State Route
(SR-) 128 in Sonoma County, south of Maacama Creek Bridge near Calistoga.
At PM 16.07 the drainage system will be repaired by replacing the westbound DI with a GT4 DI and the eastbound DI with a G2 DI. A short reach of 24-inch corrugated steel pipe (CSP) culvert with a TEE dissipator will be constructed to discharge runoff onto the existing rock slope protection (RSP) pad. The alignment of the drainage culverts will remain unchanged.
Loose material, debris, and vegetation on the failed slope will be removed. A soldier pile wall with concrete lagging will be constructed to prevent further progression of the slipout. The proposed wall is estimated to be approximately 80 feet long and will retain a maximum height of 10 feet. The embankment will be reconstructed and permanent erosion control installed.
The roadway and structure will be excavated and reconstructed. The roadway will be repaved and any striping/pavement delineation replaced.
At PM 16.16 The existing undermined section below the concrete pad will be repaired using cement slurry to backfill the cavity. Loose debris within the washout area will be removed and the slope will be excavated an additional one foot below the failure plane boundaries. RSP fabric Class 8 will be placed over the excavated areas in conformance with Standard Specification Section 72-2.02C. Class VI 3/8-ton RSP (Type A Placement) will then be placed over the RSP fabric. Rock voids will be filled with excavated material per District Landscape Architect recommendations. A 3-point bearing for rocks must be achieved. The top of the RSP will be filled with shotcrete for a 4-inch shotcrete layer. Shotcrete must be added one inch at a time.
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
128
Other Location Info
The project is located at post miles (PM) 16.07 and 16.16 on State Route (SR-) 128 in Sonoma County, south of Maacama Creek Bridge near Calistoga.
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 project and were not developed in response to any specific environmental impacts resulting from the project.
Attachments
Notice of Exemption
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