Description

Good afternoon GFXers! This is my first submission in the month of May. I'll provide a brief story and some technical information to give you a bit of background.

As many of you know, I work for the Metropolitan Water District of Southern California. I was invited out to one of the project sites our company is working on called the Inland Feeder Arrowhead Tunnels. At this particular location, two tunnels are being bored through the San Bernardino Mountains to collect water from Lake Arrowhead and divert it to Diamond Valley Lake in the event that San Diego has a drought, they will be supplied water via secondary means. Anyhow, this image shows the TBM ($9M tunnel boring machine) breaking through the face of granite rock 22,000 feet through previously mined tunnel on the other side of 8,000'. The tunnel itself is 19' in diameter and when lined and complete will have a 16' diemeter pipe running through the middle! You could drive a large SUV through it, no trouble!

Needless to say, this project has been ongoing for the last 12 or so years, taken so long partially do to politics and money! If you want more details, feel free to PM me! I am very lucky to have witnessed this firsthand! It's not everyday this happens! Thanks for viewing!

To answer a question, the 19' diameter tunnel boring machine met the previously mined tunnel off by only 3". The alignment was performed via GPS! To be off 3" is quite accurate!

Best Regards,
Tommyguns

Time Exposure
Nikon D200
Nikor 18-70mm f3.5/4.5

See larger version for best detail!