As we proceed eastbound on Colorado 58 towards Interstate 70, we follow Clear Creek past Golden and Coors Brewery. Alluvium consisting of coarse sand and gravel has been deposited by the creek to a thickness of 40-60 feet in the valley bottom and 20-40 feet on the sides of the valley. Ground water is present in most of this alluvium and flows from the margins of the valley toward Clear Creek where it discharges to streamflow. Thus, Clear Creek gains streamflow through most of its length. The alluvial aquifer and the stream function as a hydrologic system in which water can flow from aquifer to stream or stream to aquifer at various points or at various times. When a gravel pit is excavated below the water table, ground water flows into the pit and will flood the pit unless the pit walls are lined with impermeable clay and rainfall and seepage are pumped from the pit. As we travel downstream along Clear Creek, you will notice numerous lakes that are formed from abandoned gravel pits now flooded by ground water.

 

U.S. Department of the Interior, U.S. Geological Survey URL: http://rockyweb.cr.usgs.gov/frontrange/virtour/highway58.htm Contact: Carol Mladinich  mailto:csmladinich@usgs.gov Updated: 05/16/2001