News

Major Closure of I-70 at Georgetown Next Week for Rock Removal

March 30, 2011- Central Eastern Colorado/CDOT Region 1 CLEAR CREEK COUNTY – The Colorado Department of Transportation (CDOT) will close both directions of Interstate 70 at Georgetown Hill for one or two days next week for a large-scale rock removal operation.

Beginning at 9 a.m. on Tuesday, April 5, eastbound and westbound I-70 will be closed to through traffic between the U.S. 40/Empire (Exit 232) and Silverthorne (Exit 205) interchanges, allowing crews to safely bring down a large, unstable cluster of boulders located on the slope above the highway.  Local traffic between Empire Junction and Georgetown (westbound) and between Silverthorne and Silver Plume (eastbound) still will be allowed to travel I-70 up to the closure points, closer to the rockfall site.  Due the number of boulders that need to be removed, the highway is expected to remain closed until 5 p.m.

“We know this closure will have major impacts but the safety of the traveling public is always our first priority.  These boulders have the potential to come down on their own and we need to remove them before that happens,” says CDOT Regional Transportation Director Tony DeVito.  “The highway has to be closed for this work but unfortunately we won’t know exactly how long it’s going to take until the work actually begins.  Each layer of rock we remove will give us more information on what remains behind it that may also need to be addressed. ”

If the mitigation is not completed on Tuesday, CDOT will need to close I-70 again from 9 a.m. to 5 p.m. on Wednesday, April 6.   In addition, CDOT may need to also repair any fencing or netting that is damaged from the falling rock and debris.

“When you’re dealing with weathered and deteriorated slope conditions and wedged rocks, there is little predicatability on “when” and “where exactly” the rocks will travel,” adds DeVito, “We absolutely cannot allow traffic to travel on Georgetown Hill while the work is occurring since falling rock could reach the roadway and break apart even further.”

CDOT, in coordination with the Georgetown Police Department, is asking residents who live below the potential path areas to evacuate their homes while removal operations are taking place for their safety.  There are about five homes that have been identified as being in the area where rocks have the potential to land.

While I-70 is closed, the primary detour routes between the Front Range and the Western Slope are:

  • I-70 to U.S. 40 (Empire Junction), U.S. 40 west over Berthoud Pass to Kremmling, and State Highway 9 south to I-70 in Silverthorne (73 miles)
  • U.S. 285 southwest to Fairplay, State Highway 9 north over Hoosier Pass to I-70 in Frisco (101 miles)

“There’s never a good time to have a full closure of I-70, especially during the daytime, but we need to get this done now because it’s the time of year we experience the recurring freeze and thaw along with those wet snows that make the mountainous areas more susceptible to rockfall,” says DeVito.  “We cannot delay this…we would rather be proactive and bring this hazard down in a controlled method than be reactive.   We will not risk public safety.”

For text and/or e-mail alerts about the project, and while work is underway, please visit www.coloradodot.info and click on the cell-phone icon in the upper right-hand corner.  A link takes you to a list of items you can subscribe to, including I-70 West, Denver to Glenwood Springs. Updates also will be available by calling 511 or checking the Web site: www.coloradodot.info

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Project Questions

  • How large are the boulders that need to be removed?

The boulders measure from two feet in diameter, up to 16 feet long, 8 feet wide and 8 feet high – about the size of a pick-up truck.

  • How many boulders need to be removed?

CDOT estimates about 40 boulders.  However, as rocks are removed, it may reveal the need for additional rock removal.

  • How will the boulders be broken apart?

Crews will use a device, known as a Boulder Buster, that can split large boulders without the flyrock and noise produced by explosives.  It uses a cartridge resembling a shotgun shell and a column of liquid to generate a high-impulse pressure wave. The pressure wave then fractures the surrounding structure. It is not rated as an explosive.

  • How high up on the slope is the cluster of boulders?

It is located about 300 feet above I-70.

  • Why can’t this work be done at night?

Daylight is required to remove boulders.  Crews need to be able to clearly see the operation and evaluate the slope for safety before reopening the highway to traffic.

  • Will the highway be closed for a full eight hours?

At this point, CDOT can’t be certain an eight hour closure will be necessary each day but it is the best estimate at this time.  The nature of the work is unpredictable but more information will become available as the operation proceeds, allowing CDOT to send out updates on how the work is progressing.

  • Why is Georgetown Hill considered such a hazardous rockfall area?

CDOT’s rockfall hazard rating system identifies and rates over 750 cut slope rockfall sites throughout the state using a combination of slope measurements, traffic data and geology.  Georgetown Hill is divided into 15 distinct cut slopes.  However, the majority of rockfall that usually impacts traffic comes from far above the cut area and up to 1,800 feet above the highway.  In addition, Georgetown Hill is the most highly-traveled, identified rockfall area in Colorado, with an average of 30,000 vehicles traveling through the area each day.

  • How long has CDOT been doing rock mitigation on Georgetown Hill?

More than 10 years.

  • How much has been spent on Georgetown Hill rockfall mitigation projects in recent years?

Between $8 and $9 million since 2006.

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