Willits Bypass Project (US Highway 101) - The Long and Winding Road of Planning, Permitting & Mitigation Implementation and Monitoring

Harry Oakes, ICF
Maureen Doyle , California Department of Transportation
Topic Area
Mitigation for Transportation Projects

In November 2016, the California Department of Transportation (Caltrans) completed construction of the Willits Bypass Project, a 5.9-mile long bypass of US Highway 101 east of the City of Willits, in Mendocino County, California. The complex and controversial project, the concept for which was first conceived in 1957, realigned US 101 with a bypass around the City of Willits. The new roadway affected endangered species and state and federally regulated resources, requiring a complex suite of permits and onsite and offsite mitigation plans. This project required collaborative and creative solutions to a broad range of environmental issues and interagency coordination.

Caltrans conducted extensive baseline studies and prepared two mitigation and monitoring plans (MMPs) to satisfy state and federal agency requirements. The MMPs covered about 32 acres of onsite mitigation and over 2,100 acres of offsite mitigation on lands with Caltrans acquired through fee title. Resources covered in the MMPs include wetlands and waters; Baker's meadowfoam and North Coast semaphore grass; riparian habitat; threatened and endangered fish; and oak woodland habitat.

Caltrans prepared mitigation construction documents and oversaw construction of the bypass project as well as all phases of mitigation implementation, maintenance and performance monitoring and reporting. Mitigation implementation, which has been phased because of the magnitude of the project, was substantially completed in November 2016. Caltrans is currently implementing the 10-year performance monitoring program which includes vegetation cover, special-status plant species, and plant survival surveys, California Rapid Assessment Method surveys, aerial surveys, stream bioassessment surveys, and groundwater monitoring. Caltrans, in coordination with the Mendocino County Resources Conservation District, is also implementing a grazing management program.

Our presentation will provide an overview of the planning, permitting and mitigation phases of the Willits Bypass Project; identify some lessons learned along the way, and present some of the early monitoring results.

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