Current Activity
Beginning May 16 and continuing through July 15, a team of engineers will be drilling holes into the embankment (sides) of the dam in various places to extract core samples, an operation which will require the closure of the Sawyer Camp Trail from the North Gate at Hillcrest Boulevard to the Jepson Laurel. Work will be on weekdays only; the trail will be open to the public on weekends and holidays.
Further Investigation
To get samples from the top of the dam, light weight drilling equipment will be flown in by helicopter during a week in August following the nesting season for eagles and other raptors. That sampling will not require the closure of the 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.
