Wilson Creek Restoration and SPGA Wall
Summary
SCH Number
2025070237
Lead Agency
California Department of Transportation, District 3
(DOT)
Document Title
Wilson Creek Restoration and SPGA Wall
Document Type
NEG - Negative Declaration
Received
Present Land Use
Caltrans Right of Way, Recreation (California State Parks)
Document Description
The project proposes to stabilize the roadway from PM 12.69 to PM 12.95 with a modified alignment and construction of retaining walls. Approximately 1,400 feet of U.S. 101 would be realigned (immediately north of the Wilson Creek Bridge) by increasing the curve radius from 1,050 feet to 1,732 feet, shifting the alignment approximately 30 feet east. Two retaining walls would be constructed to stabilize the roadway beginning at the north end of the Wilson Creek Bridge: a 695-foot-long by 55-foot-high soldier pile ground anchor (SPGA) wall along the western shoulder below the highway, and a 595-foot-long by 19-foot-high soil nail wall (SNW) along the eastern shoulder. The northbound passing lane would be reduced in length from 1.54 miles to 1.26 miles by moving the southern limit north. The northbound passing lane currently begins south of the Wilson Creek Bridge and, upon completion of the project, would begin north of the SNW. The southbound passing lane would also be reduced by approximately 300-feet, moving the southern terminus from south of the Wilson Creek Bridge to immediately north of the Wilson Creek Bridge. Reducing the length of the passing lanes allows for a smaller environmental footprint and improves safety with a larger curve radius, increased shoulder width, and more uniform traffic speeds (see project layouts in Appendix A).
Currently, the lane configuration through the project area consists of four 10-foot-wide travel lanes, a northbound lane with a passing lane and a southbound lane with a passing lane. Existing shoulder widths throughout the project limits can be as little as 1-foot-wide to 6-feet-wide. The project would adjust the lane configuration on the Wilson Creek Bridge to have one 12-foot-wide northbound lane and one 12-foot-wide southbound lane with a 4-foot-wide median. Shoulder widths on the bridge would vary from 5.5 to 8-feet-wide on the northbound side, and from 8 to 19-feet-wide on the southbound side. North of Wilson Creek Bridge, the realigned roadway segment would be configured with one 12-foot-wide lane in each direction, one 12-foot-wide southbound passing lane, a 4-foot-wide median, 8-foot-wide southbound shoulder, and a 10-foot-wide northbound shoulder using 0.70 feet Class 2 Aggregate Base (CL2AB) and 0.40 feet of Hot Mix Asphalt-Type A (HMA-A).
Roadway excavation, including a 20-foot-wide access road, would total approximately 44,000 cubic yards (CY). Most of this excavated material would be used for construction of the SPGA wall and much of the material would be used to backfill or rebury the wall after it is constructed. After the SPGA wall is backfilled, an estimated 5 to 10 feet would remain above ground. Of the 44,000 CY of total material excavated, the estimated asphalt material to be hauled offsite permanently is approximately 12,000 CY. Material that is permanently hauled offsite would be disposed of at a commercial disposal site. Approximately 10,000 CY of material would likely be temporarily stockpiled at the existing pullout along the southbound lane from PM 12.98 to PM 13.15. The remaining 22,000 CY of material is expected to be temporarily stockpiled offsite. The offsite stockpiling location would be determined at a later phase of the project and would undergo applicable environmental compliance requirements.
Additional work includes cold planing along the entire alignment on either side of Wilson Creek Bridge. Work occurring on the bridge would be limited to restriping. The project also includes the following work items:
-drainage replacement and realignment
-placing geosynthetic pavement interlayer (GPI) at joints
-installing a centerline rumble-strip and shoulder rumble strips where full shoulder is present
-replacing rock slope protection (RSP) for an existing rocked drainage ditch near the northern bridge abutment and at culvert outlets
-erosion control
-traffic control
-cold planing
-replacing signs, replacing guardrail, delineators, and culvert markers in conflict with other work items (all guardrail systems being replaced would have minor concrete vegetation control placed underneath and standard galvanized steel posts and rails to be used instead of etched, stained, or otherwise treated posts and rails)
-restriping
-constructing a temporary access road
Contact Information
Name
Terra McAuliffe
Agency Name
Caltrans
Job Title
Environmental Scientist
Contact Types
Lead/Public Agency / Project Applicant
Phone
Location
Coordinates
Cities
Klamath
Counties
Del Norte
Regions
Unincorporated
Cross Streets
U.S. 101 from postmile 12.6 to 13.2
Zip
95548
State Highways
U.S. 101
Waterways
Wilson Creek
Notice of Completion
State Review Period Start
State Review Period End
State Reviewing Agencies
California Air Resources Board (ARB), California Coastal Commission (CCC), California Department of Conservation (DOC), California Department of Fish and Wildlife, Marin Region 7 (CDFW), California Department of Fish and Wildlife, Northern and Eureka Region 1 (CDFW), California Department of Forestry and Fire Protection (CAL FIRE), California Department of Parks and Recreation, California Department of Toxic Substances Control (DTSC), California Department of Transportation, District 1 (DOT), California Department of Transportation, Division of Transportation Planning (DOT), California Department of Water Resources (DWR), California Fish and Game Commission (CDFGC), California Governor's Office of Emergency Services (OES), California Highway Patrol (CHP), California Native American Heritage Commission (NAHC), California Natural Resources Agency, California Regional Water Quality Control Board, North Coast Region 1 (RWQCB), California State Coastal Conservancy (SCC), California State Lands Commission (SLC), California Transportation Commission (CATC), Department of General Services (DGS), Office of Historic Preservation, State Water Resources Control Board, Division of Drinking Water, State Water Resources Control Board, Division of Drinking Water, District 1, State Water Resources Control Board, Division of Water Quality, State Water Resources Control Board, Division of Water Rights, State Water Resources Control Board, Divison of Financial Assistance
Development Types
Transportation:Highway/Freeway (Construction of retaining walls to stabilize the roadway)
Local Actions
Coastal Permit
Project Issues
Aesthetics, Biological Resources, Greenhouse Gas Emissions, Hydrology/Water Quality, Mandatory Findings of Significance
Public Review Period Start
Public Review Period End
Attachments
Draft Environmental Document [Draft IS, NOI_NOA_Public notices, OPR Summary Form, Appx,]
Notice of Completion [NOC] Transmittal form
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