Current Activity
A team of engineers are drilling holes in the underwater portion of the San Andreas Dam. The drillers are using a barge in the lake as their platform. Sawyer Camp Trail will remain closed until September 30 to accommodate mowing and culvert repair projects undertaken by San Mateo County Parks.
Further Investigation
In October, to get samples from the top of the dam, light weight drilling equipment will be flown in by helicopter following the nesting season for eagles and other raptors. That sampling will not require the closure of the trail. This portion of the work will not require closure of Sawyer Camp Trail.
Core Analysis and Model Building
The cores extracted will be about 3-inches in diameter and 18-inches in length. They will be used to determine the content of the bedrock and fill used to create the layers of the earthen dam. Once the analysis is made and the layers determined, the engineers will create a 3-D model of the dam. This model will be used to see if previous earthquakes have weakened or changed the characteristics of the dam in ways that will need to be corrected. Also, the model can predict if the current conditions will need to be supplemented in order to prevent future problems due to earthquakes or other natural disaster.
While the sampling will take just a few weeks of activity, the evaluation effort will extend for several years.
San Mateo County Parks Closes Crystal Springs Regional Trail through Sept. 30
San Mateo County Parks is also taking advantage of the summer weather to perform regularly scheduled maintenance along Crystal Springs Regional Trail. They have incorporated the dates for their projects – from June 1 to September 30, including some weekends -- into a map of the trail. You can learn about specific trail segments and closure dates using the QR code and links in the flyer posted under Project Materials.
PG&E Gas Transmission Project through November 23
Through November 23, PG&E is excavating a portion of the San Andreas segment to inspect the subsurface gas transmission line and to install new monitoring and reporting devices. This is part of PG&E's regional efforts to improve its management systems. During the project, a 0.5-mile portion of the 2-mile San Andreas segment will be closed 7 days a week. The closed portion spans from the northern entrance at San Bruno Ave to the electric gate a half a mile south.
For up to date information on trail closures, visit San Mateo County Park's Website.
