GENERAL37309

• Permit No: C1980007
• IBM Index Class Name: General Documents
• Doc Date: 10/25/2007
• Doc Name: Review of Change Order No. 3 Monument Dam
• From: Water Resources
• To: Barr Engineering CO
• Permit Index Doc Type: General Correspondence
• Media Type: D
• Archive: No

STATE OF COLORADO
OFFICE OF THE STATE ENGINEER
Division of Water Resources
Department of Natural Resources
1313 Sherman Street, Room 818
Denver, Colorado 80203
Phone [phone]
FAX [phone]
http://www. water. state. co. us
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Bill Rirer, Jr.
Governor
Hams D. Sherman
Executive Director
(Vacant)
State Engineer
Mr. Phillip Solseng
Ban Engineering Co.
4700 West 77`s Street
Minneapolis, MN 55435
October 22, 2007
RECEIVED
ocr 2 5 2007
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Mining and Safety
When replying, please refer to:
MONUMENT DAM
Construction File No.: C-1676A
Water Division 4, Dam ID: 400413
Subject: Review of Change Order No. 3
Modifications to the Approved Construction Documents
Deaz Mr. Solseng:
Thank you for submitting Change Order No. 3 for the Monument Dam Modifications in Gunnison
County for our review and acceptance in accordance with Rule 9.1.8 of the State of Colorado's "Rules and
Regulations for Dam Safety and Dam Construction." This change consists of modifying the following:
I. Reducing the length of the trench drains by approximately 60 feet. This modification lowered the
Factor of Safety from 1.01 to 1.00 under the extreme seismic case.
2. Using an on site source of riprap material consisting of a soft to medium hazd sandstone. The Los
Angeles Abrasion tests performed on two samples indicate that the material does not meet the
CDOT Standard Specification 506.02 of 50 percent loss after 1,000 revolutions. To compensate
for the softer material the D50 of the material will be increased from 6 to 12 inches and the
thickness will range from 12 to 18 inches. Also, the incorporation erosion protection is an
improvement over the existing condition in which the upstream slope had no erosion protection.