The San Diego County Water Authority board of directors last week certified the environmental impact report to raise San Vicente Dam by 117 ft.
The $568-million project, to be built on top of the existing San Vicente Dam in Lakeside, will expand the reservoir to hold an additional 52,000 acre-ft of water for use during emergencies and another 100,000 acre-ft of water to supplement imported supplies during dry periods.
The Dam will be constructed of roller compacted concrete and will reportedly be the largest dam raising ever performed in the US and the largest using roller compacted concrete in the world. (Photo by O’Connor Construction Management, Inc.)
Back in March of 2008 there was a landslide that closed SR 87 in between Phoenix, Arizona and Payson. It’s been of great interest to me since it is in my state and affected a highway. I was hoping my firm (NCS Consultants, LLC) might be asked to work on the remediation through our on-call contract but it didn’t happen. Its probably for the best, it sounds like it’s been a troublesome geotechnical engineering problem. Fast forward to last week, and the slide area was in the news again because the slope is still moving and apparently causing some additional deformation of the roadway. (Photo by ADOT)
I had heard about this a while ago through our ADOT contacts, but I make it a policy not to take advantage of my contacts through my day job for GeoPrac.net content (not without permission anyway). So I didn’t want to blog about it until it hit the mainstream media. Last week, the Arizona State Geologist blogged about the SR 87 slide moving again, as did Ken through his AEG Arizona Section blog. It was even covered on one of my favorite blogs, Dave’s Landslide Blog. I finally have a chance to wade through these blog posts and some of the reports and videos to present a summary of the situation, available information and offer my own perspective. (More after the break)