REP28184

• Permit No: C1981041
• IBM Index Class Name: Report
• Doc Date: 3/28/1989
• Doc Name: 1988 Annual Hydrologic Report
• Annual Report Year: 1988
• Permit Index Doc Type: HYDROLOGY REPORT
• Media Type: D
• Archive: No

POWDERHORN COAL COMPANY
1988 ANNUAL HYDROLOGIC REPORT
• OCTOBER 1, 1987 THROUGH SEPTEMBER 30, 1988
INTRODUCTION
Powderhorn's Roadside and Cameo Mines continued to be in temporary cessation
during the 1988 hydrologic year. Monitoring was done in accordance with
the schedule approved on pages 207-209a (revised 10-23-87) of our permit
application. Monitoring schedule changes for this year included elimination
of Colorado River and loadout piezometer monitoring and reduction in in
the frequency for monitoring on the refuse pile piezometers and the Rapid
Creek-Cottonwood Creek piezometers.
SURFACE WATER MONITORING
The results of monitoring on the Colorado River during the 1988 water year
are recorded on data pages SB-1 and SC-1. Monitoring requirements for
these sites was eliminated in the Permit Renewal approved in January 1988.
The USGS operates a monitoring station upstream of the mines on the Colorado
River approximately 3 miles, Station 09095500 or Station 955. The following
is a list of total flows for the last 5 years and the average flow for
1933 -1988:
• Mater Year
1984
1985
1986
1987
1988
1933-1988 Ave.
Total Acre-Feet
5,521,000
4,304,000
4,9',156 , 000
2,596,000
2,154,000
2,860,000
1 of 56 Year Ave.
193
150
320
91
75
Using the the average monthly conductivity and total monthly flows a mass
average conductivity of 799 umhos/cm was calculated for 1988. The river
carried approximately 1.62 million tons of TOS past the mine (Calculated
using average conductivity/TDS ratios from our monitoring of the river).
Monitoring of flow in Cottonwood Creek and Rapid Creek continued to be
done with Stevens recorders during the periods of time required. Tables
588-1 through 588-8 were prepared using the average of 4 regularly spaced
readings per day from the recorder charts. A graphical representation
of this data is shown on Diagrams S88-1 through 588-4. The following is
a tab]e of average daily flow for the months when stream flow is most critical
for irrigation, July - October:
SW6S-O1
Water Year October July August September
1985 3.64 CFS - - -
. 1986 = 6.10 - -
1987 2.70 2.31 1.27
1988 1.90 1.71 1.06 1.68
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