REP46375

• Permit No: C1984062
• IBM Index Class Name: Report
• Doc Date: 7/13/1987
• Doc Name: 1986 AHR REVIEW
• From: MLRD
• To: COLO YAMPA COAL CO
• Annual Report Year: 1986
• Permit Index Doc Type: Hydrology Report
• Media Type: D
• Archive: No

III. SURFACE WATER

The salt load contribution for Mine No. 3 to t4iddle Creek for calendar year
1986 was estimated to be 1,323 tons. .Approximately 283 tons were contributed
from parts of Mine No. 3 north of County Road 33 and 1,039 tons were
contributed from Mine No. 3 south of the road. An undetermined amount of salt
was contributed to Fish Creek through spoils springs discharging into the Fish
Creek Tipple pond. These spoils springs are the discharge point for aquifers
present in adjacent backfilled Mine No. 3 spoils.
The salt load contribution to Middle Creek by Mine No. 3 is much less than the
salt load contribution of Foidel Creek to t9iddle Creek. Foidel Creek contains
spoils springs and mine inflow discharges from the Eckman Park and Foidel
Creek Mines. The annual salt load of Foidel Creek at site 09243900 is
10,187 tons. Middle Creek contributes approximately 2,600 tons of salt from
the drainage basin above site 2437. The salt load contribution from Mine No.
3 is approximately 10 percent of the salt load present at the confluence of
Middle and Foidel Creeks.
The salt contribution from Mine No. 3 results in a salinity increase of
approximately 6 percent in tdiddle Creek. The TDS concentration of Middle
Creek above Mine No. 3 averaged 664 mg/1 (2437) for 1986. The TDS
concentration for Foidel Creek averaged 1929 mg/1 for calendar year 1986. An
average TDS concentration calculated at the confluence of Middle and Foidel
Creek was 979 mg/1. The average TDS concentration for site 29 during 1986
downstream of Mine No. 3, was 1039 mg/1. A 6 percent increase in the salinity
of Middle Creek is therefore attributed to Mine No. 3.
Analysis of the TDS and discharge data for site 29 did not indicate an
increase in the salt load of Mine No. 3, but under estimated the salt load in
Middle Creek below Mine No. 3 by 9 percent. The error is attributed to errors
in the discharge curve for site 29. Water quality data for site 29 closely
follows the water quality calculated for the confluence at Middle and Foidel
Creeks. The similarity between the confluence water quality calculated from
sites 2437 and 2439 and the TDS concentration recorded at site 29 indicates
that the water quality recorded at site 29 is correct (Figure 4). The site 29
discharge curve consistently under-estimates the discharge (Figure 5). The
annual yield calculated for Middle Creek at the confluence with Foidel Creek
(summation of yield for sites 2437 and 2439) is 10352 acre-feet for 1986. The
annual yield recorded at site 29 was 7994 acre-feet for calendar year 1986;
29.5 percent less than the calculated annual yield at the confluence. The
error in the discharge rating curve results in under-estimation of the yield
and salt load from the basin above site 29. The failure to accurately reflect
the actual discharge and salt load s especially prronounced during spring peak
flows (Figure 5, 6).
IV. SURFACE WATER QUALITY
Analysis of water quality data recorded at sites 2439 and 60 in Foidel Creek
and sites 2437 and 29 on Middle Creek indicates that no excessive
concentrations of metals or other constituents were contributed to Middle
Creek from Mine No. 3, The Middle and Foidel Creek systems show a seasonal
variation of metal concentrations where elevated concentrations of metals are