My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
PERMFILE138596
DRMS
>
Back File Migration
>
Permit File
>
300000
>
PERMFILE138596
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
8/24/2016 10:39:16 PM
Creation date
11/26/2007 7:54:10 AM
Metadata
Fields
Template:
DRMS Permit Index
Permit No
C1980007
IBM Index Class Name
Permit File
Doc Date
6/2/2006
Section_Exhibit Name
Exhibit 72 Preventative Measure, Geotechnical Eval, Seismic Eval for Monument Dam
Media Type
D
Archive
No
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
58
PDF
Print
Pages to print
Enter page numbers and/or page ranges separated by commas. For example, 1,3,5-12.
After downloading, print the document using a PDF reader (e.g. Adobe Reader).
View images
View plain text
Geotechnical Evaluation o1 Mineā¢Induced Seismicity on Monument Dam <br />Dorsey 8 Whitney, LLP <br />Section 8 -Conclusions <br />The dam and reservoir are currently operated under restrictive orders by the SEO that <br />have been in place since 1980 and modified restriction since about 1994 because of <br />numerous dam safety concems. The restriction has been modified to allow increased <br />storage up to the emergency spillway elevation (conditional full storage) for a few <br />months during the summer, subject to site inspection and verification of instmment <br />data by the SEO and in accordance with increased monitoring requirements. <br />3. The active landslide is the uppermost part of a series of landslides that have <br />repeatedly failed from the left valley slope and are expected to also underlie and form <br />the foundation of the earthfill dam. No movement has been associated with the <br />underlying, older, landslides. The active landslide that forms the left abutment of the <br />dam, and through which the emergency spillway channel is cut, is an integral <br />component of the overall dam and reservoir system. Documented site observations <br />and instrument data during the period 1985 to 2004 provide atime-line of an <br />episodic, but generally continuous, record indicative of landslide movements, with <br />total movement on the order of 0.5 to greater than 1.0 foot at some locations. The <br />situation posed by the landslide is considered to be impending failure for the landslide <br />and dam and associated potential for release of the reservoir. <br />2. Dam safety concems include inadequate spillway capacity, seepage exiting at high <br />elevation on the downstream face of the dam and associated slumps, cracks observed <br />in the dam crest and downstream embankment that are associated with movement of <br />an active landslide identified in the left abutment, and an undersized low-level outlet <br />conduit that is pressurized through the dam embankment. <br />Inclinometer instrumentation, which provides important information at the landslide <br />failure surface itself, has not been usable since about 1995 due to landslide <br />movements. Since 1995 estimation of landslide movement has been accomplished <br />using only surface instrumentation and observations of surface cracks. <br /> <br />GEI <br />The cast-iron outlet conduit, which is subject to the reservoir water pressure head <br />along its full length through the embankment because flow is controlled by a valve at <br />the downstream end of the conduit, is a dam safety concern. The outlet conduit is <br />also undersized to effectively release water from the reservoir under emergency <br />conditions. <br />27 <br />060350ObLJ~16 Manummt Dam GmisdwW Ev,l <br />March 2006 <br />
The URL can be used to link to this page
Your browser does not support the video tag.