My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
8105
CWCB
>
UCREFRP
>
Copyright
>
8105
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
8/11/2009 11:34:21 AM
Creation date
5/22/2009 12:31:02 PM
Metadata
Fields
Template:
UCREFRP
UCREFRP Catalog Number
8105
Author
Haines, G. B., D. W. Beyers and T. Modde.
Title
Estimation of Winter Survival, Movement and Dispersal of Young Colorado Squawfish in the Green River, Utah.
USFW Year
1998.
USFW - Doc Type
Recovery Program Project 36,
Copyright Material
YES
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
18
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 />272 Y.K. CONVERSE ET AL. <br />Table III. Number of electrofishing samples among reaches and shoreline types <br />Reach Shoreline type Total <br /> Bedrock Cobble Debris fan Sand Talus Vegetation <br />I 69 21 92 36 164 63 445 <br />2 27 15 20 7 49 56 174 <br />3 2 2 5 4 12 20 45 <br />Combined 98 38 II7 47 225 139 664 <br /> <br />To account for changes in habitat condition and habitat use with discharge, we used discharge data <br />from two USGS gauge stations. For analysis of physical habitat changes within the study area, discharge <br />data from the gauge station located above the confluence of the LCR were used (station number <br />93831(0). The discharge at this station most closely reflected the actual discharge within the study area at <br />the time of data collection. <br />For analysis of long-term changes in the overall flow regime, data from the gauge station located at <br />Lee's Ferry was used (station number 9380000), because this station maintained the longest period of <br />record. We used the latter data to derive flow duration curves (see Data collection) for pre- and post-dam <br />periods of the Colorado River in Grand Canyon, which allowed us to compare differences in the flow <br />regime since construction of Glen Canyon Dam. <br /> <br />Data collection <br />Geomorphic reaches. To quantify differences in reach geomorphology, the total length of each of the <br />shoreline types and surficial riffle area along the entire 24-km study area was mapped and the mean <br />width-to-depth ratios of each reach was calculated. Surficial riffle area was defined as a relatively shallow <br />area that was characteristically broken or rippled by fast water moving over underlying cobble but that <br />lacked standing waves. The total available shoreline of each type was mapped on mylar overlays of <br />1 :24000 scale aerial photographs. The percentage riffle area in reaches was then mapped and shoreline <br />mapping was verified in the field. The channel transect data of Schmidt and Graf (1990) taken at arbitrary <br />cross sections throughout the study area were used to derive an average width-to-depth ratio for the three <br />geomorphic reaches. <br />Shoreline longitudinal transects. Three habitat variables along 100 m lengths within different shoreline <br />types were quantified. We refer to one set of measurements as a longitudinal transect. At each lO-m <br />interval along a transect, water depth and water velocity were measured (at 0.6 of depth) and the presence <br />of cover types was recorded. We assumed that shoreline structure most strongly influenced channel <br />hydraulic conditions within 2.5 m of the shoreline and, therefore, measured depth, velocity and cover at <br />three distances from shore: 0.5, 1.5 and 2.5 m. The presence of three cover types was recorded: lateral (L), <br />instream (I) and overhead (0) (Table IV). Cover was based on lateral, emergent or overhead shelter from <br />hydraulic or visual exposure. We tallied the presence of each cover type at each point, and then <br />summarized the frequency of cover for each longitudinal transect. Each longitudinal transect comprised <br /> <br />Table IV. Definition of cover types <br /> <br />Cover type Definition <br /> <br />Lateral Any laterally emerging in stream structure that obstructs flow and provides shelter from the main <br />current above, below or beside it <br />Instream Any instream structure emerging vertically from the river bottom that obstructs flow and provides <br />shelter from the current in its wake <br />Overhead Any structure from the shore that hangs above the water in the channel margins <br /> <br />.f) 1998 John Wiley & Sons, Ltd. <br /> <br />Re~ul. Rivers: Res. M~mt. 14: 267-284 (1998) <br />
The URL can be used to link to this page
Your browser does not support the video tag.