The Willits Bypass Mitigation project included wetland construction, wetland planting, riparian planting and erosion control. Constant biological monitoring was needed due to the sensitivity of project (wildlife conservation, water quality, non-use of herbicides, and ground disturbance issues). Although CPM schedule allowed Hanford 2 years for the heavy civil construction; Hanford completed it all in 500 days.

Acres Restored: 116

Land Type: Riparian And Seasonal Wetland

Cubic Yards Moved: 140,0000

Contract amount: $24M

Project Period: 2015-2020

Native Plants Installed: 2,000,000


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The purpose of the project was to mitigate project activities from the Hwy 101 Bypass construction. The project scope included constructing 45 acres of wetlands, wetland native plant installation, and erosion control installation. Additionally, 71 acres of the riparian habitat within the project area were treated with topsoil scraping to encourage native plant establishment.

The Project was located in sensitive habitat which subjected the project activities to SWPPP and other environmental permits. Hanford worked with biological monitors for all project activities to ensure native plants and animals were not negatively impacted by project actions.

In 2015, approximately 55,000 plants were installed, in 2016 approximately 536,000 plants were installed.


Hanford graded a total of 14,000 CY of material in a project area whose water table was at, or just below, grade level. This required Hanford to employ specialized equipment to prevent over-compaction of graded areas as well as preventing injury to staff and equipment.

This project includes a maintenance component which is on-going. Due to the sensitivity of the project area, all non-native species control will be via mechanical methods (no chemicals are permitted). Hanford will also water the 2,000,000 native plants installed, as needed, to ensure optimal health and survivorship.