Yampa River Overview

• Description: Yampa River Management Plan
• State: CO
• State: UT
• State: WY
• Basin: Yampa/White/Green
• Water Division: 6
• Date: 1/1/3000
• Title: Yampa River Overview
• Water Supply Pro - Doc Type: Report/Study

Table 4. Mean and Standard Deviation of Inflection Points all riffles above Cross
Mountain (Strata 6 and 8 combined).
Variable vs. Flow
Units
N
NI*
MEAN
STD
C.V.
Wetted Perimeter
(cfs)
53
1
185
87.52
0.47
( %)
53
1
59%
0.13
0.23
Wetted Width
(cfs)
53
1
207
80.93
0.39
(ft rT
53
1
207
58.00
0.28
Average Depth
(cfs)
48
6
146
64.60
0.44
(ft)
48
6
0.67
0.26
0.39
Change in Stage
(cfs)
53
1
157
70.10
0.44
(ft)
53
1
1.21
0.44
0.36
Width /Depth Ratio
(cfs)
54
0
182
63.86
0.35
54
0
325
181.28
0.56
Average Velocity
(cfs)
54
0 1
174 1
67.33
1 0.39
(ft/s)
54
0 1
1.58 1
0.59 1
0.37
Tables 3 in Appendix V.A and VI. A show the stream width for each of the riffle
cross sections for Strata 6 and Strata 8 respectively. The average stream widths for each
flow were plotted (Figures 5 of Appendix 5A and 6A) and the inflection point for that
curve was identified using the same approach as individual cross sections (Table 5). The
inflection points for Strata 6 and Strata 8 were 80 cfs (43% wetted perimeter) and 200 cfs
(57% wetted perimeter), respectively (Table 5). The inflection point determined by this
method (Method B) produced a lower value than the mean of individual inflection points
(Table 4).
The t -test was used to determine if there was a significant difference between
wetted stream widths for Strata 6 and Strata 8 (Appendix VII, Table 1). The null
hypothesis was that mean stream widths were similar between strata and it was not
rejected at an alpha of 0.05.
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