WSP02988

• File Number: 8200.760
• Description: Yampa River General
• State: CO
• Basin: Yampa/White
• Water Division: 6
• Date: 1/1/1976
• Author: Stearns-Roger
• Title: Environmental Study - Hayden and Craig Colorado - Phase D - Annual Report - 1976
• Water Supply Pro - Doc Type: Report/Study

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Nocturnal surface-based temperature inversions were present for 61.1 percent of the time
during 1976 or an average of 14,7 hours per day, These inversion conditions typically
formed at sunset and continued throughout the night. After sunrise the incoming solar
radiation began to heat the ground and the air immediately above creating thermal eddies
which gradually spread upward, At the I aD-foot level, the nocturnal inversion was broken
between 1000 and 1100 MST, on the average, and between 1100 and 1200 MST at 200 feet.
The maximum average temperature gradient of the nocturnal inversion was 3.20Fj180 feet
or 3,20C/1 aDM,

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CRAIG WATER RESOURCES

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Water resollfces in the vicinity of Craig Station were studied during 1976 by various groups
including Steams-Roger, Utah International, USGS and the Colorado Department of Health,
The Yampa and Williams Fork Rivers were the subjects of these studies, The program
conducted by Steams-Roger consisted of a series of quarterly water samples on the Yampa
River. The results of similar sampling by the other groups also are included, With respect to
some parameters, the water quality of the Yampa River decreases with distance
downstream, Alkalinity, calcium, chloride, conductivity, iron, magnesium, silica, sodium,
sulfate and total dissolved solids exhibit higher concentrations at Craig than at Hayden.
Concentration of major ions, with the exception of iron and manganese, were below values
specified by the U.S. Public Health Service drinking water standards, The late Winter early
Spring samples taken prior to the Spring runoff exhibited highest concentrations perhaps
due to the increased importance of lowland snow melt and of tributaries with lower water
quality,

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Trace element concentrations are quite comparable between the Craig and Hayden areas,
Thc wide range of values found at most Yampa River sampling stations suggests that the
differences are not statistically significant.

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CRAIG AIR QUALITY

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Air quality studies during 1976 were directed toward documenting ambient concentrations
of sulfur dioxide and suspended particulates during construction of Craig Station, Recorded
sulfur dioxide concentrations were on the order of only 3 to 4 percent of the National
Ambient Air Quality Standards, Wind direction data suggests that the town of Craig was the
source of the low sulfur dioxide concentrations, Concentrations of suspended particulates
slightly exceeded the Federal secondary and State 24-hour standards in the vicinity of the
Craig Station construction site and in the nearby town of Craig, Previously collected
baseline measurements also had shown concentration exceeding applicable standards,

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