8132

• UCREFRP Catalog Number: 8132
• Author: Lieberman, D. and T. Burke.
• Title: Limnology and Drift of Particulate Organic Matter Through the Lower Colorado River.
• USFW Year: 1991.
• USFW - Doc Type: Denver, CO.
• Copyright Material: NO

3-5
3.0
2.5
E 2.0
a 1.5
1.0
0.5
0.0
PHASE 1, 1986- 1987
® LESS THAN 25 um
N GREATER THAN 505 Y.m
25-505 µ.m
DAVIS PARK PARKER HEADGATE PALO CIBOLA IMPERIAL YUMA
DAM N10AB1 DAM ROCK VERDE DAM
Figure 4.-The <25-µm, 25- to 505-µm, and >505-µm size-fractions of POM during phase 1 at all sampling stations
(Oct. 1986 to June 1987).
Table 8.-F-test results based on ANOVA
between all stations and <25-µm dry
weight (DW), and <25-µm POM for
phase 1 (Oct. 1986 through June 1987).
<25-µm Dry weight, DW
15.77 Yuma A'
9.94 Imperial Dam B
5.87 Cibola B
4.71 Palo Verde Diversion Dam
238 Headgate Rock Dam
2.24 Parker Dam
2.23 Park Moabi
1.73 Davis Dam
<25-µm POM
2.42 Yuma A
1.40 Imperial Dam B
1.39 Cibola B
0.87 Palo Verde Diversion Dam B
.82 Parker Dam
.73 Davis Dam
.66 Park Moabi
.65 Headgate Rock Dam
Mean Station Tukey
g/m3 grouping
C
C
C
C
C
C
C
C
C
C
C
. Means with the same grouping are not signif-
icantly different at the 0.05 confidence level.
The >25-µm size-fraction POM accounted for 5 to 25
percent of the total POM at all stations-increasing
at downstream stations in both magnitude and
percentile. The >25-µm size-fraction POM did not
fluctuate greatly between sampling periods at
upstream stations; generally it was less than 0.10
g/m3 from Davis Dam to Palo Verde Diversion Dam.
This size-fraction showed an increase in POM at
stations downstream of Palo Verde Diversion Dam.
A peak occurred in the >25-µm size-fraction POM
in January 1987 at both Imperial Dam and Yuma
corresponding to increased flows. Mean concentra-
tions, g/m3, of the >25-µm POM were:
- Davis Dam (upstream) ...... 0.06
- Park Moabi ................. .09
- Parker Dam ................ .05
- Headgate Rock Dam ........ .08
- Palo Verde Diversion Dam ... .10
- Cibola ..................... .46
- Imperial Dam ............... .72
- Yuma ...................... .73
Mean concentrations at Yuma and Imperial Dam
were statistically different from the other stations,
as was the mean for Cibola (table 9).
The >505-µm POM-considered the coarse POM-
was the largest and most visible size-fraction, but
it accounted for less than 5 percent of total POM.
At Imperial Dam, the >505-µm POM ranged from
0.01 to 0.13 g/m3. The mean of 0.04 g/m3, at
Imperial Dam, represents the highest concentration
of this size-fraction compared with other stations;
but statistically, there were no differences between
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