My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
WSP10328
CWCB
>
Water Supply Protection
>
Backfile
>
10001-10999
>
WSP10328
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
1/26/2010 2:58:21 PM
Creation date
10/12/2006 4:16:35 AM
Metadata
Fields
Template:
Water Supply Protection
File Number
8273.400
Description
Colorado River Basin Salinity Control - Federal Agencies - Bureau of Land Management
Basin
Colorado Mainstem
Water Division
5
Date
3/27/2002
Author
Schumm and Gregory
Title
Diffuse-Source Salinity -- Mancos Shale Terrain
Water Supply Pro - Doc Type
Report/Study
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
185
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).
Show annotations
View images
View plain text
<br />W <br />\-" <br />t,';> <br />,-,J <br /> <br />Between 1965 and 1983 decreasing dissolved-solids concentrations <br />were detected at 20 stations on the Colorado River and tributaries <br />(Kircher, 1984). Increasing concentrations were detected in three <br />tributary streams (Dolores R. near Cisco, Utah, Little Snake R. near <br />Lily, Co.,. Virgin R. at Littlefield AZ). Three stations showed no <br />change. The decreased concentration can be due to several factors! for <br />example this period was one of major reservoir filling, improved <br />irrigation practices and, attempts to control point-source salinity. In <br />addition, beginning in about 1940 and continuing to about 1980 there was <br />a substantial reduction of grazing pressure on the Public Lands, which <br />was accompanied by a marked improvement of range conditions (U.S. Bureau <br />of Land Management, 1985). In order to understand the salinity problem <br />in the Upper Colorado River Basin short and long term salinity <br />variations must be understood, and this will involve a geomorphic <br />overview of the basins with special attention being paid to channel <br />changes with time. <br /> <br />Geology <br /> <br />The Colorado River Basin drains all or parts of five physiographic <br />provinces. Middle and Southern Rocky Mountains, Wyoming Basin, Colorado <br />Plateau, and Basin and Range Provinces. <br />Highly erodible shales are exposed throughout the Upper Colorado <br />River 8asin lowlands. Because of its thickness, usually over 600 m and <br />at times over 1000 m, the outcrop area of Mancos Shale is the largest <br />among the sedimentary rocks (Figure l-6). Mancos Shale has been studied <br />more than any other formation in connection with salinity because of its <br />large exposures, its erodibiE ty, and its high SMC. The name Mancos was <br />first applied in 1899 by Cross (Fisher, Erdmann, and Reeside, 1961) to <br />exposures of shale near the town of Mancos in southwestern Colorado. <br />The Mancos Shale is a shallow-water marine formation. It is thinly <br />bedded and dark gray, when fresh. The shale contains numerous veinlets <br />of gypsum .and calcite, and when weathered it is a lighter gray. The <br />surface is a friable, semi-powdery mass when dry that becomes sticky and <br />impervious when wet. It includes a few thin layers of bentonite, <br />calcareous sandstone, and shaly limestone. In places it includes <br /> <br />11 <br /> <br />1,. <br /> <br />.".,.,-'",-<",-,,, <br /> <br /> <br />-~ <br />-1 <br /> <br />';- <br />,j <br />j <br /> <br /> <br />i,;", :k,,_i <br /> <br />
The URL can be used to link to this page
Your browser does not support the video tag.