WSP05120

• File Number: 8200.760
• Description: Yampa River General
• State: CO
• Basin: Yampa/White
• Water Division: 6
• Date: 1/1/1983
• Author: USGS
• Title: Reservoir Development Impacts on Surface-Water Quantity and Quality in the Yampa River Basin - Colorado and Wyoming - 1983
• Water Supply Pro - Doc Type: Report/Study

001893

Air Temperature, Relative Humidity, Cloud Cover,
Wind Velocity, and'Radiation

Mean monthly values for air temperature, relative humidity, cloud cover, and
wind velocity used in the single-reservoir model were obtained from a climatic at-
]'as of the United States (National Oceanic and Atmospheric Administration, 1968).
These monthly values then Were interpolated to obtain daily values for the single-
reservoir model by weighting the monthiy change to the number of days for each
month. Daily radiation waS computed by a subroutine in the single-reservoir model
that used data on air temperature, relative humidity, and cloud cover.

Water Temperature

Daily water temperatureS collected since late 1950 were available for,one
streamflow-gaging station on the Yampa River (site 53, figs. 3 and 4) and one
streamflow-gaging station on the Little Snake River (site 79, ,figs. 3 and 4)
(Wentz and Steele, 1976). Oai ly water-temperature data were used only for site-
specific estimates of inflow water temperature to individual reservoirs and not
for the basinwide analyses. Intermittent water-temperature measurements (4 to
12 values per year) have been collected at the above 2 sites and at 32 additional
streamflow-gaging stations throughout the basin; the majority of the temperature
data has been collected since 1961 (Wentz and Steele, 1976). All data were ana-
lyzed using a harmonic-analysis technique (Steele, 1972; 1974) to characterize the
annual variabil ity of stream temperatures at these measurement sites (Wentz and
Steele, 1980).

Harmonic coefficients obtained for individual sites may be regional ized as
functions of selected basin characteristics using linear, bivariate-regression
equations (Steele, 1976a; Lowham, 1978; Wentz and Steele, 1980). In this manner,
Information On stream-temperature characteristics in terms of ambient seasonal'
variability may be transferred to stream locations within the basin where few or
no data are available. The harmonic and regional-regression analyses were used to
estimate daily water temperatures of inflow to the proposed reservoirs considered
in this study.

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Specific Conductance

Daily records of specific conductance were avai lable for two downstream
streamflow-gaging stations: Yampa River near Maybell (site 53, fig. 3) and Little
Snake River near Lily (site 79. fig. 3). Specific-conductance data were collected
at selected sites as part of reconnaissance or quarterly sampling basinwide sur-
veys made between August 1975 and September 1976 (Steele and others, 1976a; 1979;
Wentz and Steele, 1976; 1980). Regionalized regression relationships based upon
discharge were developed from measurements of specific conductance and were used
to estimate monthly average concentrations of major solutes and issolved solids
for the dissolved-solids model.

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