My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
9323
CWCB
>
UCREFRP
>
Public
>
9323
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
7/14/2009 5:02:34 PM
Creation date
6/1/2009 11:55:07 AM
Metadata
Fields
Template:
UCREFRP
UCREFRP Catalog Number
9323
Author
Cooper, D. J. and C. Severn.
Title
Wetlands of the Ouray National Wildlife Refuge, Utah
USFW Year
1994.
USFW - Doc Type
Hydrology, Water Chemistry, Vegetation, Invertebrate Communities, and Restoration Potential.
Copyright Material
NO
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
81
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
These regression analyses illustrate a number of important <br />points. (1) The May and June regressions for the pre-Flaming <br />Gorge water years have higher maximum flows than the post-Flaming <br />Gorge water years. (2) The regression lines are steeper for the <br />pre- than the post-Flaming Gorge regressions, which indicates <br />that differences between regression lines for each month is <br />greater the larger the water year. Smaller water years have peak <br />flows that are more similar to pre-dam flows. Thus, maximum <br />flows are the most modified aspect of these hydrographs, and they <br />are most dramatically changed for the larger water years, which <br />typically are the years that cause the most channel change, allow <br />woody riparian plant species (such as cottonwoods) reproduce, and <br />allow fishes to move from the river onto the large floodplain. <br />(3) The differences are particularly large between the June <br />regressions; June 1,946-1962 has the highest regression line, <br />while June 1963-1993 the lowest. <br />As shown in Figure 2, average to large water years have <br />total annual flows of 3 to 4 million acre feet. Using the <br />regressions shown in Figure 8 it can be determined that the <br />maximum June flows pre- and post-Flaming Gorge are different by <br />7,000 to 9,000 cfs. For example, a runoff year producing 3 <br />million acre feet would have had a peak discharge of <br />approximately 20,000 cfs pre-Flaming Gorge, but a peak nearer <br />13,000 cfs post-Flaming Gorge. A runoff year producing 4 million <br />acre feet would have had a peak discharge of approximately 26,000 <br />cfs pre-Flaming Gorge, while today a peak of 17,000 is predicted. <br />Flows of 13,000 to 17,000 cfs may not allow overbank <br />flooding to occur in the study area, whereas flooding would have <br />occurred during these same water years pre-Flaming Gorge. These <br />difference are significant when considering the potential for <br />using controlled releases from Flaming Gorge Reservoir to create <br />the types of flows required to flood the Ouray Bottoms which will <br />provide environments suitable for native fishes and plant <br />species. <br />Figure 4 illustrates the fact that the overall <br />characteristics of the Green River hydrograph at Jensen are <br />derived from Yampa River flows. The approximately 4,300 cfs <br />discharged from Flaming Gorge increased the duration of high <br />water, but the peak discharges are still significantly below what <br />might have been expected on the Green River prior to dam closing. <br />The 1993 water year was the largest since 1986, yet the period of <br />high water was quite short, and the peak flow was not high (see <br />Figure 3). Only one day had a flow exceeding 20,000 cfs. Prior <br />to 1963 the 1993 water year may have produced flows greater than <br />20,000 cfs for up to 2 to 4 weeks duration. Overbank flows <br />occurred for approximately 2 weeks this year, but prior to <br />Flaming Gorge Dam may have occurred for 4 to 7 weeks. This <br />extensive period of inundation would have been long enough for <br />larval fishes to move into floodplain wetlands, grow for more <br />14 <br />
The URL can be used to link to this page
Your browser does not support the video tag.