2019-03-11_REPORT - C2009087 ‎(2)‎

• Permit No: C2009087
• IBM Index Class Name: Report
• Doc Date: 3/11/2019
• Doc Name: Annual Hydrology Report
• From: Peabody Sage Creek Mining, LLC
• To: DRMS
• Annual Report Year: 2018
• Permit Index Doc Type: Hydrology Report
• Email Name: TNL
• Media Type: D
• Archive: No

NPDES Discharge Point 004 (NPDES4).
In 2018 004 was monitored in April, July and August, when cattle were
present. This year's average flow value, 0.240 cfs, is 17% lower than
the historic (1983-2018) average flow value, 0.290 cfs. The timing of
when flow values are collected affects these averages. Flow values from
Pond 004 have also been affected by the reduced diameter of the
discharge culvert modified on May 29, 1987 (36 -inches to 6 -inches). In
August 2005, the discharge culvert was replaced with an 8 -inch diameter
plastic culvert set approximately one -foot above the previous elevation.
On August 20, 2015, the old Parshall flume was replaced with a new 2 -
foot H -flume. Review of the TDS plot indicates an increasing trend,
however the peak value occurred in September 2005, therefore it appears
to be stabilizing.
Surface Water Site SW -S2-10 (SSC10).
This site monitors Cow Camp Creek below Pond 004 at its confluence with
Fish Creek. This site was monitored in April, June and July in 2018. No
flow was observed for both the June and July monitoring events in 2018.
This site usually dries up in late summer, although NPDES4 upstream
flows continuously. The reduction in flow is due to stream channel
infiltration, evapotranspiration and the absence of lateral inflow from
tributaries to Cow Camp Creek. The TDS plot reveals an increasing trend;
however, the April 2018 TDS concentration was less than previous years.
Little Grassy Creek Drainage.
Two monitoring sites lie within the Little Grassy Creek drainage: SSLG5,
located in the upper part of Little Grassy Creek, and NPDES Discharge
Point 002, also known as the Wadge Impoundment or Pond 002.
Surface Water Site SW -S2-5 (SSLG5).
Site 5 drains the upper reaches of Little Grassy Creek which are
undisturbed by mining. A comparison of its hydrograph to that of NPDES2
indicates that Site 5 is a relatively minor contributor to the flow in
this basin. The TDS plot indicates an increasing trend. This site was
monitored in April, June, July and September in 2018. No flow was
observed in June, July and September of this year.
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