WSP05674

• File Number: 8200.760
• Description: Yampa River General
• State: CO
• Basin: Yampa/White
• Water Division: 6
• Date: 3/1/1978
• Author: USGS
• Title: Analysis of Waste-Load Assimilative Capacity of the Yampa River - Steamboat Springs to Hayden - Routt County - Colorado - March 1978
• Water Supply Pro - Doc Type: Report/Study

0025S8

Table 3.--Nonionized ammonia (NH3) for observed pH and temperature
values, Yampa River, September 23-24, 1975

Average
Locationl temperature, pH pH
in degrees range median
Celsius
YM-O---------- 10 8.4-8.7 8.6
YM-01--------- 10 8.3-8.8 8.5
YM-1---------- 10 8.3-9.0 8.6
YM-2---------- 10 7.1-8.1 7.8
YM-3---------- 10 7.2-8.7 7.8
YM-4---------- 10 7.2-8.9 8.1
YM-5---------- 10 7.5-8.9 8.2
YM-6---------- 11 8.2-9.1 8.7
YM-7---------- 11 7.8-9.0 8.2
YM-8---------- 11 8.0-9.0 8.2
YM-9---------- 11 7.9-8.7 8.1
YM-10--------- 11 7.9-8.5 8.3
YM-11--------- 11 7.9-8.6 8.1
YM-12--------- 12 7.3-8.4 7.5
YM-13--------- 12 7.4-8.4 7.7
YM-14--------- 12 7.0-8.8 8.2
lSee figure 6.

NH3 range
(percentage
of total
ammonia)

4.5- 8.5
3.6-10.5
3.6-15.7
.2- 2.3
.3- 8.5

.3-12.9
.6-12.9
3.1-20.2
1.3-16.7
2.0-16.7

1.6- 9.1
1. 6- 6.0
1.6- 7.4
.4- 5.2
.5- 5.2
.2-12.0

In the nitrogen-cycle fitting process by both models, it was the intent
to fit the nitrite-pIus-nitrate nitrogen and organic nitrogen more closely
than the ammonia nitrogen. This was decided upon ,because there was no
possible means to fit the observed ammonia-nitrogen profile with a first-order
decay function with the models being used. As was noted earlier, the
comparison between computed versus observed nitrite-pIus-nitrate nitrogen and
organic-nitrogen concentrations in the upstream subreaches of the Yampa River
from sites YM-Ol to YM-5 was thought to be adequate. Because the ammonia
nitrogen is part of the nitrogen cycle, this procedure results in conservative
estimates of ammonia-nitrogen concentrations.

A comparison of observed and computed orthophosphate concentrations is
shown on figure 20. This constituent represents another critical nutrient for
the plant community in the stream system. The orthophosphate-concentration
profiles computed by the U.S. Geological Survey and Pioneer-I models differ
more in the downstream part of ~he study reach. Both models appear to compute
higher values than the observed average or single values. The orthophosphate-
concentration profiles were computed assuming phosphorus to be a non-
conservative substance and neglected the effects of nonconservative organic
inputs of phosphorus. The orthophosphate computations of both models use two

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