Nov 152017
 
Water Resources Investigation WRI 2017-1a, The Upper Pierre Aquifer of the Cheyenne Basin, Northeastern Colorado, Geologic Cross Sections

Our friends over at the Colorado Division of Water Resources (CDWR) have just released Water Resources Investigation WRI 2017-1a, The Upper Pierre Aquifer of the Cheyenne Basin, Northeastern Colorado, Geologic Cross Sections, authored by Ralf Topper, Clinton D. Meyer, Marshall Haworth, Kevin C. Donegan, Hillary Banks, Aaron Bandler, Andrew Flor, and Matthew A. Sares.

Summary:

This report is a compilation of ten regional geologic cross sections created from interpretation of geophysical logs from 200 oil and gas wells. It is the first of a two-part hydrogeologic study of the Upper Pierre aquifer within the Cheyenne Basin of northeastern Colorado and consists of a short text report along with 11 plates. The cross sections depict the following geologic/hydrogeologic intervals: South Platte River alluvial aquifer, Ogallala Formation, White River Formation, Laramie Formation, Fox Hills Sandstone, Upper Pierre Shale upper confining layer, Upper Pierre aquifer, Pierre Ash, and the Upper Pierre Shale lower confining layer.

The text, maps, and cross sections may be downloaded from the DWR Homepage in the “New!” section in the middle of the page.

Contact Matthew A. Sares, Manager, Hydrogeological Services with any questions.

Feb 232017
 

Feb 102017
 

Feb 012017
 

By Jill Carlson

On March 23, 2003, a large avalanche occurred about one mile west of the Town of Silver Plume. The avalanche brought trees, rock, soil and snow to the valley floor, knocked down overhead utility lines, blocked the I-70 frontage road, damaged the town’s water treatment plant (WTP), and dammed Clear Creek. The dam was breached using explosives before the plant’s electric pump motors were flooded. With damage to the WTP’s chlorine contact tank and building, Silver Plume residents had to boil their tap water for over a month.

The avalanche occurred three days after near-record snowfall. It was triggered by additional snow loading in the starting zone caused by a change in wind direction, and began in a known avalanche path above timberline on Pendleton Mountain. Its unusually large volume and velocity caused it to unexpectedly reach the valley floor, along a path not previously identified as an avalanche chute. Rick Gaubatz, the Town’s water commissioner, counted 110 rings in a spruce tree that was found in the avalanche debris at the damaged WTP, indicating that an avalanche of similar magnitude had not occurred in the immediate area in at least 110 years.

Avalanche debris in the runout zone taken by Xcel Energy from a helicopter on the morning after the avalanche occurred, 24 March, 2003.

Avalanche debris in the runout zone taken by Xcel Energy from a helicopter on the morning after the avalanche occurred, 24 March 2003.

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Jan 242017