Devil's Slide Improvement Project

Route 1 from Half Moon Bay Airport to Linda Mar Boulevard in Pacifica,

San Mateo County, California

DRAFT

SECOND SUPPLEMENTAL ENVIRONMENTAL IMPACT STATEMENT/

SECOND SUPPLEMENTAL ENVIRONMENTAL IMPACT REPORT

ALL COMMENTS ON THIS DOCUMENT MUST BE MADE IN WRITING TO:

Robert Gross, Chief
Office of Environmental Planning, South
Caltrans District 4
P.O. Box 23660
Oakland, CA 94623-0660

2.0 PURPOSE OF AND NEED FOR PROJECT


The purpose of this project is to provide a safe, dependable and stable State highway route to bypass the geologically unstable area of Route 1 at Devil's Slide in San Mateo County (see Project Location Map, Figure 2-1 and Project Area Map, Figure 2-2). The instability of Devil's Slide and the problems with the existing roadway through that area remain the same as set forth in the FEIS approved on April 16, 1986. Since the construction of the existing Devil's Slide portion of Route 1 in 1937, several geologic factors have contributed to landslides, falling rocks, and subsiding grade resulting in diminished roadway width. Despite drainage improvements, pavement reinforcement and rock anchors, Route 1 continues to experience difficulties and closures due to landslides and roadway subsidence. Such closures create a tremendous inconvenience to Coastal residents and results in severe economic impacts on Coastside businesses and families.

In addition to the road closures listed in Table 2, page 23 of the 1986 Devil's Slide FEIS, similar closures have continued to occur since that document was written. One of the longest lasting road closures in the area occurred in 1995, and lasted 158 days (from 1/22/95-6/30/95), and cost $2,983,000 to repair. The most recent closure, from 2/27/98 to 3/2/98 was caused by a rock slide.

 

 

FIGURE 2-1: Regional Location Map


Map created with TOPO!TM 1996 Wildflower Productions

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FIGURE 2-2: Project Area Map


 

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