Last Chance Grade Geotechnical Risk Assessment Released, Public Open House Scheduled for July 19
Last Chance Grade Geotechnical Risk Assessment, July 19 Public Open House
Caltrans is pleased to announce the release of a Geotechnical Risk Assessment for Last Chance Grade, the coastal stretch of U.S. Highway 101 four miles south of Crescent City in Del Norte County known for its susceptibility to landslide activity. The document will help Caltrans narrow down long-term solutions for the area.
Caltrans and the Federal Highways Administration (FHWA) pulled together an independent panel of geotechnical experts with a combined 180 years of experience to work on the assessment. Using 3D enhanced technology and other methods, they analyzed the geological conditions of proposed alternate routes inland and compared those routes to the option of making major upgrades to the existing alignment.
“The panel did some excellent work,” said Caltrans District 1 Director Matt Brady. “This will help us make sure the long-term solution we eventually select for Last Chance Grade won’t have the same problems we’re facing today."
For example, the expert panel estimated that the alternate route with a full tunnel would have a very high resistance to landslide-related closures within a 50-year period, but it could also potentially have higher cost increases. The graphic included in this release summarizes the resistance to geotechnical-related closures over 50 years for each alternative.
“The assessment will serve as one of many tools that will be used to narrow down alternatives that will be fully studied during the project’s environmental phase, which is set to begin next year,” said Last Chance Grade Project Manager Jaime Matteoli.
There will be a public open house on July 19 at the Del Norte County Fair Grounds from 6:30 to 8 p.m. where project staff will be able to present the findings of the Risk Assessment and provide other updates. There will also be a Q&A session including Caltrans and our partners.
The release of the Risk Assessment follows the 2016 release of a Project Study Report for Last Chance Grade, which provided insight on potential project concerns related to the environment, cultural preservation, design, and right of way.
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Click here to view or download the Last Chance Grade Geotechnical Risk Assessment.
Click here to view or download our informational brochure regarding the project and the upcoming Open House.
Frequently Asked Questions about the Geotechnical Risk Assessment:
- Does the Geotechnical Risk Assessment evaluate safety?
- No, it doesn't have to. Any structure Caltrans opens to the public is and will be safe. Every option seen on the included graphic will meet design standards and seismic standards if built. We know these standards result in a safe facility.
- Is there a best option?
- Not yet. While the Geotechnical Risk Assessment does shed light on what’s least likely to close in a 50-year period, we have other factors to consider for each alternative such as how likely it is to be funded, what it will cost to construct and maintain, what are the environmental resources there, what are the cultural resources there, and what are the values of our partners and stakeholders.
- When will we select a long-term solution for Last Chance Grade?
- This is years down the road after we’ve circulated the environmental document, fully understand the impacts and mitigation needs of each alternative, and have received comments from the community.