Sustainability is integral to the Willits Bypass Project

willits_valley_2Learning more about the sustainable approach and care that has gone into the Willits Bypass Project offers special insight into Caltrans’ application of contemporary and world-class engineering practices. This is definitely not our grandfather’s way of constructing a highway.

Every major project Caltrans develops follows a rigorous process of environmental consideration and review that directly shapes every aspect of a project, from the various alternatives analyzed during the planning phase to the way Caltrans ultimately minimizes, and then compensates for any unavoidable construction impacts to the natural environment.

During the early stages of a project, Caltrans coordinates with regulatory agencies to evaluate project alternatives in order to identify and determine what is called the “Least Environmentally Damaging Practicable Alternative,” or LEDPA. The LEPDA is the only alternative that can receive a permit for construction from the U.S. Army Corps of Engineers, which is the administrator of the U.S. Clean Water Act on behalf of the U.S. Environmental Protection Agency.

Each project is unique to their location, and for the Willits Bypass Project, Caltrans proposed a practicable alternative that offered the least impact to wetlands and was practicable in accordance with the requirements of the U.S. Clean Water Act.

Since adoption of the final environmental document prepared by Caltrans for the Willits Bypass Project in 2006, several design elements and refinements have been incorporated into the project that further reduce the overall project footprint and impact area, avoiding or minimizing effects on aquatic resources. Some major examples include the reduction in the roadway median width to reduce the bypass alignment footprint; and incorporation of steeper-than-standard embankment slopes at some locations, with additional erosion control measures to minimize the bypass alignment footprint. Improvements that will help fish habitats will also be included.

Drawing of fish passage improvements on Heahl Creek which include the removal of an existing culvert and adding rock weirs.

Drawing of fish passage improvements on Heahl Creek which include the removal of an existing culvert and adding rock weirs, which are structures used to slow and control stream flow.

Finally, after the initial environmental impact avoidance and minimization measures have been incorporated into the project, Caltrans also compensates for project impacts. Our mitigation plans must demonstrate that the compensation meets or exceeds the potential impact to the environment, or to any endangered species.

“For compliance with the California Endangered Species Act, Caltrans compensated for an unavoidable impact to habitat for the threatened North Coast semaphore grass. Fill for the bypass roadbed will cover three tenths of an acre of an occurrence of this listed species Caltrans discovered. It was known to exist in only limited amounts in Little Lake Valley. Over the course of several years Caltrans worked with the Department of Fish and Wildlife to identify and locate several other occurrences of the species elsewhere in the valley. To offset the project impact, Caltrans purchased several of these parcels containing the newly discovered populations, and through a long-term endowment will protect, enhance, manage, and monitor over eight acres of the sensitive grass in perpetuity,” said Chris Collison, a senior resource biologist with Caltrans.

One of many soil pits used to document the existing soil conditions on our mitigation properties.

One of many soil pits used to document the existing soil conditions on our mitigation properties.

Finalized in 2012, Caltrans developed a Mitigation and Monitoring Proposal designed to offset any unavoidable project impacts. Much of the proposed mitigation plan includes the establishment, reestablishment, and rehabilitation of wetlands and other waters, and is designed for mitigation lands to be self-sustaining into the future. The proposal seeks to compensate for the project’s wetland impacts by enhancing the wetland functions on over 1,400 acres, establishing 50 acres of new wetlands, restoring several miles of riparian habitat (along the bank of the stream) and threatened salmon habitat, and also improving water quality in several of the streams in Little Lake Valley.

The Willits Bypass has undergone significant study and analysis using an up-to-date process with sustainability in mind. Caltrans invites you to take a deeper look into our work in developing this project. Find out more using the links below.

Willits Bypass Project News – The bypass will improve fisheries

Willits Bypass Project News – Dozens of alternative routes were studied

Willits Bypass Project Mitigation and Monitoring Proposal (January 2012)