default avatar
Welcome to the site! Login or Signup below.
|
Not you?||
Logout|My Dashboard

Tunnel diggers hit large flow of water

Print
Font Size:
Default font size
Larger font size

Posted: Friday, November 13, 2009 12:00 am | Updated: 5:27 pm, Tue Feb 14, 2012.

Earlier this month, Devil’s Slide tunnel diggers tapped into the biggest underground reservoir they’ve encountered to date, according to Caltrans. A steady gush of water did not slow the project, however.

Caltrans workers were probing the northbound tunnel face to get a sense of hydrology in the mountain ahead when they struck a water pocket – all part of the process, says chief spokeswoman Lauren Wonder. What’s unique about the pocket is it rendered a 150 gallon-per-minute flow, by far the fastest to date. Typical groundwater pockets workers have found produce flows ranging between 5 and 60 gallons per minute, Wonder said.

When asked if the heightened flow indicates workers have tapped into a larger water body, Caltrans spokesman Bob Haus answered, “Pretty much.”

“It’s the difference between punching a hole in a small bucket of water versus a large bucket,” he said.

Diggers punctured three holes to drain the reservoir, capping them with hoses that channel the water to a sump pump that empties into a storage tank outside the tunnels. After treatment, the water is funneled into the ocean.

The discovery didn’t hinder diggers – they directed their focus to another part of the tunnel while the reservoir drained. Wonder said flow is expected to dissipate to about 5 gallons per minute by this weekend.

Welcome to the discussion.

Recent comments

Posted 14 hours ago by John Gruver.

article: Cafe Gibraltar prepares to close its do…

Returning to the theme...

More...

Posted 16 hours ago by bigse94019.

article: Cafe Gibraltar prepares to close its do…

"As far as coffee, there’s nothing better on the coast for service, consistency/price at Starbucks and Petes." I disagr…

More...

Posted Yesterday by Dick Granada.

article: Cafe Gibraltar prepares to close its do…

Coastsiders vote with their dollars. A agree that Café Gibraltar was unique and reasonable but not supported enough by locals. F…

More...

Posted 2 days ago by John Gruver.

article: Cafe Gibraltar prepares to close its do…

Lynn and I started eating a Cafe Gibralter when it was still in Montara. A short walk to and from, best food on the coast (absolu…

More...

Popular/Commented Stories