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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HA YDEN AIR QUALITY

Ambient ]evels of sulfur dioxide, sulfates and suspended particulates near Hayden Station
were documented in 1976 prior to and after commencement of Unit 1I operation, Sulfur
dioxide levels in the vicinity of Hayden Station showed a maximum 3-hour concentration of
73 parts per billion by volume (PPBV) which is only 15 percent of the 500 PPBV National
Ambient Air Quality Standard (NAAQS), The maximum observed 24-hour sulfur dioxide
concentration was 17 PPBV which is ] 2 percent of the 140 PPBV standard, A sulfation
plate network consisting of 62 sites was established around Hayden Station, During an
exposure period of 90 days, detectable levels of sulfate equivalent to an average sulfur
dioxide concentration of ]] PPBV was found, Suspended particulate measurements in the
area indicate that primary NAAQS are met, but secondary NAAQS and Colorado standards
are being slightly exceeded, which is typical of most locations in semi-arid Colorado,

CRAIG ECOLOGY

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Ecological studies conducted near Craig Station during ]976 were limited to a study of
alfalfa plots to determine the baseline levels of foliar injury occurring in the area. In
addition, a study was initiated to determine the significance of water stress in producing
foliar injury in alfalfa,

The incidence of necrotic and chlorotic foliar injury was extremely low on the alfa]fa sites
examined, The percentage of leaflets showing necrosis was too low to analyze while
chlorosis averaged approximately one percent, Since the Craig Station was not operational,
the injury was probably produced by other environmental factors, The water stress study
indicated that levels of foliar moisture was higher in August than in Ju]y. During these
sampling periods, the incidences of foliar chlorosis were not significantly different. Study
results indicate that levels of injury recorded on the plots represent background levels and
that these levels of injury were independent of the level of water stress the plants were
experiencing.

CRAIG METEOROLOGY

Meteorological observations were taken during ] 976 at the 200-foot tower located
immediately south of the Craig Station. Wind speed, wind direction and temperature data
were recorded at three tower levels with relative humidity and solar insolation recorded at
the lowest level.

The two dominant wind directions follow the orientation of the Yampa River Valley,
Wind flow patterns show a counterclockwise shift of the prevailing directions from
south-southwest at the 20-foot level, through southwest at the ]OO-foot level, to
west-southwest at the 200-foot level. In the Northern Hemisphere, this observed effect is
due to the decreasing of surface frictional forces with height above the ground, Average
annual wind speeds show a daytime maximum and a nighttime minimum, All levels show a
Winter minimum increasing during the Spring and reaching a maximum during June with a
rapid decrease in average speed beginning in Ju]y,

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