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Boulder County Commissioners reject agreement with Denver Water Board on the proposed Gross Reservoir expansion
Jan 8th
After hearing to more than six hours of public testimony over a span of two public hearings – Dec. 20 and Jan. 7 – and receiving more than 200 written communications from Boulder County residents, the Board of County Commissioners unanimously decided not to support the IGA.
The intergovernmental agreement was signed by the Denver Water Board on December 19, 2012, and would have served in lieu of review of the reservoir expansion project under the Boulder County Land Use Code. The IGA had been negotiated by the staffs of Boulder County and Denver Water as a way to address the impacts of the project and to define appropriate mitigation measures, but ultimately didn’t go far enough in protecting the quality of life for residents in the area in the opinion of the County Commissioners.
While they acknowledged some benefits that would result from the proposed agreement, the County Commissioners indicated that the terms of the proposed agreement did not do enough to protect the health, safety and welfare of their constituents or the environment and that they thought it was premature to enter into any agreement before the release of the Final Environmental Impact Statement, which is due later in 2013.
Following the release of the final EIS, the commissioners will work with county staff on a thorough response to the findings, and continue to work with members of the public to address ongoing concerns about the impacts of the proposed project.
Visit www.bouldercounty.org/property/build/pages/moffatgrossiga.aspx for more information. To view the archived video from last night’s hearing, visit the hearings page and select the business meeting for Jan. 7 at www.bouldercounty.org/gov/meetings/pages/hearings.aspx.
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Boulder OSMP to Open Lower Chapman Drive Trail
Jan 5th
The City of Boulder Open Space and Mountain Parks (OSMP) will open the new Chapman Drive Trail and Trailhead to the public on Jan. 7, 2013. This trail is an extension of the current Chapman Drive Trail that begins at Realization Point on Flagstaff Drive. Visitors will be able to travel from Boulder Canyon Drive (SH 119) at the Red Lion Inn all the way to Flagstaff Drive.
The new trail was made possible by the recent purchase of the Schnell property. The 2005 Visitor Master Plan proposed the use of Chapman Drive as a multi-use trail and the new section was included in the recent West Trail Study Area Plan. There is a small trailhead with parking at the northern end of the trail along SH 119.
“At this time, we are opening the trail to pedestrians, equestrians, telemark skiers and snow shoers,” said Annie McFarland, OSMP Visitor Access Coordinator. “Bikes will also be allowed, going uphill only. Cyclists not able to complete the 2.5 mile ride uphill, must dismount and walk bicycles downhill if they wish to return to the trailhead at SH 119. Cyclists completing the trail have the option of riding down Flagstaff Drive to Canyon back to the trailhead.”
All users must remain on the trail and no dogs are permitted north of the Tenderfoot Trail intersection.
Throughout January OSMP will meet with key stakeholder groups and interested parties to seek feedback on how best to manage visitor use – in particular bike and dog access on the lower part of Chapman Drive. OSMP will conduct an analysis of each alternative and then develop a matrix of possible management options. The department will host a mid-February open house for public feedback. Individuals may also submit comments regarding visitor use by email. Go to www.osmp.org and click on ‘Contact us’ on the bottom right of the home page. In your email, specify ‘Chapman Drive Trail’.
More information including a map of the area can be found at:
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For additional trail updates on OSMP properties, please call 303-441-3440 or visit www.osmp.org.
CU Boulder research team finds massive crevasses and bendable ice affect stability of Antarctic ice shelf
Dec 7th
Gaping crevasses that penetrate upward from the bottom of the largest remaining ice shelf on the Antarctic Peninsula make it more susceptible to collapse, according to University of Colorado Boulder researchers who spent the last four Southern Hemisphere summers studying the massive floating sheet of ice that covers an area twice the size of Massachusetts.
But the scientists also found that ribbons running through the Larsen C Ice Shelf – made up of a mixture of ice types that, together, are more prone to bending than breaking – make the shelf more resilient than it otherwise would be.
The research team from CU-Boulder’s Cooperative Institute for Research in the Environmental Sciences presented the findings Dec. 6 at the American Geophysical Union’s annual meeting in San Francisco.
The Larsen C Ice Shelf is all that’s left of a series of ice shelves that once clung to the eastern edge of the Antarctic Peninsula and stretched into the Weddell Sea. When the other shelves disintegrated abruptly – including Larsen A in January 1995 and Larsen B in February 2002 – scientists were surprised by the speed of the breakup.
Researchers now believe that the catastrophic collapses of Larsen A and B were caused, at least in part, by rising temperatures in the region, where warming is increasing at six times the global average. The Antarctic Peninsula warmed 4.5 degrees Fahrenheit since the middle of the last century.
The warmer climate increased meltwater production, allowing more liquid to pool on top of the ice shelves. The water then drained into surface crevasses, wedging them open and cracking the shelf into individual icebergs, which resulted in rapid disintegration.
But while the meltwater may have been responsible for dealing the final blow to the shelves, researchers did not have the opportunity to study how the structure of the Larsen A and B shelves may have made them more vulnerable to drastic breakups – or protected the shelves from an even earlier demise.
CU-Boulder researchers did not want to miss the same opportunity on the Larsen C shelf, which covers more than 22,000 square miles of sea.
“It’s the perfect natural laboratory,” said Daniel McGrath, a doctoral student in the Department of Geography and part of the CIRES research team. “We wanted to study this shelf while it’s still stable in order to get a better understanding of the processes that affect ice shelf stability.”
McGrath worked with CIRES colleagues over the last four years to study the Larsen C shelf in order to better understand how the warming climate may have interacted with the shelf’s existing structure to increase its vulnerability to a catastrophic collapse.
McGrath presented two of the group’s key findings at the AGU meeting. The first was the role that long-existing crevasses that start at the base of the shelf and propagate upward – known as basal crevasses – play in making the shelf more vulnerable to disintegration. The second relates to the way a type of ice found in areas called suture zones may be protecting the shelf against a breakup.
The scientists used ground penetrating radar to map out the basal crevasses, which turn out to be massive. The yawning cracks can run for several miles in length and can penetrate upwards for more than 750 feet. While the basal crevasses have been a part of Larsen C for hundreds of years, the interaction between these features and a warming climate will likely make the shelf more susceptible to future disintegration. “They likely play a really important role in ice-shelf disintegration, both past and future,” McGrath said.
The research team also studied the impact of suture zones in the ice shelf. Larsen C is fed by 12 distinct glaciers, which dump a steady flow of thick ice into the shelf. But the promontories of land between the glacial outlets, where ice does not flow into the shelf, allow for the creation of ribbon-like suture zones, which knit the glacial inflows together and which turn out to be important to the ice shelf’s resilience. “The ice in these zones really holds the neighboring inflows together,” McGrath said.
The suture zones get their malleable characteristic from a combination of ice types. A key component of the suture zone mixture is formed when the bottoms of the 12 glacial inflows begin to melt. The resulting freshwater is more buoyant than the surrounding seawater, so it rises upward to the relatively thinner ice zones between the glacial inflows, where it refreezes on the underside of the shelf and contributes to the chaotic ice structure that makes suture zones more flexible than the surrounding ice.
It turns out that the resilient characteristics of the suture zones keep cracks, including the basal crevasses, from spreading across the ice shelf, even where the suture zone ice makes up a comparatively small amount of the total thickness of the shelf. The CIRES team found that at the shelf front, where the ice meets the open sea, suture zone ice constitutes only 20 percent of the total thickness of the shelf but was still able to limit the spread of rifts through the ice. “It’s a pretty small part of the total ice thickness, and yet, it still has this really important role of holding the ice shelf together,” McGrath said.
Other CU researchers involved in the Larsen C project were Konrad Steffen, former director of CIRES; Ted Scambos, of CIRES and CU-Boulder’s National Snow and Ice Data Center; Harihar Rajaram, of the Department of Civil Engineering; and Waleed Abdalati, of CIRES.