PERMFILE103529

• Permit No: M2005066
• IBM Index Class Name: Permit File
• Doc Date: 10/13/2005
• Doc Name: Reclamation Permit Application Form
• From: Asphalt Paving Company
• To: DMG
• Media Type: D
• Archive: No

Martin and Wood Water Consultants, Inc.
• 602 Park Point Drive, Suite 275, Golden, CO 80401
Phone: [phone] . Faz: [phone]
www.marOnandwaod.com
May 3, 2005
Mr. Jeff Keller
Asphalt Paving Company
14802 W. 44`n Avenue
Golden, CO 80403
Re: Wattenberg Lakes, Perry Pits
and Wattenberg West Pit
Ground Water Modeling Study
Project Number 625.2
Dear Mr. Keller:
This letter report presents the results of our investigations into the predicted ground water
conditions that will result from the slurry lining of gravel pits located adjacent to the Town of
Wattenberg in Weld County, Colorado. There has been concern raised over the potential impacts to
the local ground water table resulting from the combined "mound and shadow" effects created by
the slurry walls that will enclose the pit azeas. To carry out our analyses, we constructed a
numerical ground water flow simulation model to make predictions as to how the existence of the
pits will change the local ground water conditions. The model was also used to develop an
understanding of the potential cumulative impacts of the lined pits on the Town's single municipal
water supply well.
The model was constructed utilizing the Groundwater Modeling System ("GMS") designed
by the Department of Defense and modified and marketed by Boss International. This softwaze
package essentially provides apre- and post-processing interface to the United States Geological
Survey "MODFLOW" model code. Both MODFLOW and GMS aze widely used by engineers and
governmental agencies in addressing ground water flow issues.
There will be a total of five sepazate slurry wall lined pits, in three general azeas, located to
the west, south, and east of Wattenberg. These five pits are owned by either Asphalt Paving
Company (Wattenberg West pit and Perry pit) or Aggregate Industries, Inc. (Wattenberg Lakes
pits). Figure 1 presents the location and configuration of the slurry walls that will surround the
various pits. The Perry pit is already mostly mined out and will have a slurry wall in place by early
summer. The Wattenberg West pit and the Wattenberg Lakes pits will be lined first and then mined
in a dewatered state. Following the completion of mining activities, all five of the pits will be put
into use for water storage.
To construct a new model encompassing the three pit areas, we modified an eazlier ground
water model of the Wattenberg West Pit azea to include the new Wattenberg Lakes and Perry pits.
The model continues to encompass an area extending from central Brighton, approximately 3.5
miles south of the pit areas, to approximately 2 miles north of the Town of Wattenberg. The width