WSP00398

• File Number: 8200.760
• Description: Yampa River General
• State: CO
• Basin: Yampa/White
• Water Division: 6
• Date: 4/1/1980
• Author: USGS
• Title: Analysis of Stream Quality in the Yampa River Basin - Colorado and Wyoming - 1980
• Water Supply Pro - Doc Type: Report/Study

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Basinwide Reconnaissance--1975

After evaluating the historic data, a complementary basinwide reconnais-
sance was planned to collect samples at 85 sites during low-flow conditions.
The locations of these sites are shown on figure 1 and are 1 isted in table 1.
All sites were visited during July 1975 to insure acc~ssibil Ity. The streams
were sampled during the last week of August and the first week of September
1975. There was no. streamflow at sites Y-3, Y-5, and Y-38A during this sam-
pi ing period. Streamflow, water temperature, pH, dissolved oxygen, and spe-.
cific conductance were measured at the remaining 82 sites; samples for labo-
ratory analyses of other physical, chemical, and biological characteristics
also were collected. The data from the basinwide reconnaissance have been
publ ished by Giles and Brogden (1978).

Quarterly Sampl ing Program--1975 to 1976

Based on the results of the basinwide reconnaissance, additional samples
were collected at 42 sites (fig. 1 and table 1) to determine the response of
stream qual ity to seasonal changes and to. variations in stream discharge.
Sampling was conducted during December 1975, and during March, June, and
August-September 1976. Thirty-two of the sites were the same as those
sampled during the basinwide reconnaissance; samples were collected at 10 new
sites to determine sediment and nutrient concentrations in streams draining
the Routt National Forest (table 1). The data from the quarterly sampl ing
program have been publ ished by the U.S. Geological Survey (1978).

Re lated Stud i es

At the present time (1979), samples are being collected monthly at 12
sites (table 1) which were included in the August-September 1975reconnais-
sance but which were not continued in the quarterly sampling program. These
samples are being collected as part of ongoing studies not directly associat-
ed with the Yampa River basin assessment (U.S. Geological Survey, 1976).

Water-quality data also have been collected at the following sites by
the Colorado Department of Health for the periods indicated (see fig, 1): (1)
Yampa River below Little Snake River (about 4 mi or 6 km upstream from site
Y-O). since 1968; (2) Little Snake River above Lily (about 6 mi .or 10 km
upstream from site Y-1) since 1968; (3) Yampa River near Maybell (site Y-17)
since 1968; (4) Yampa River at t1ilner (immediately upstream from Trout Creek)
since 1968; and (5) Yampa River above Oak Creek confluence (about 1 mi or
2 km downstream from site Y-71) since 1970. Published analyses for Sage
Creek, Grassy Creek, and the Yampa River in the vicinity of the water intake
for the Hayden Powerplant for the period 1971-76 also are available (Stearns-
Roger, Inc., 1973-76). Because of variations in techniques used in the
collection and analyses of water samples, only stream-temperature data from.
the above sources have been used in this study. However, results of aquatic-
biological studies by Eddy (1975), Ames (1977), and Canton and Ward (1977)
have been considered in the analyses of data presented in this report.

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