HYDRO21033

• Permit No: C1981019
• IBM Index Class Name: Hydrology
• Doc Date: 1/12/1998
• Doc Name: 3rd Qtr 1997 STORM WATER EXEMPTION
• From: CDOH
• To: COLOWYO COAL CO
• Permit Index Doc Type: DMR’s
• Media Type: D
• Archive: No

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STATE OF COLORADO
Roy Romer, Governor
Patti Shwayder, Exec .tire Director
L~dicaud to protecting and improving the health ar. d environment o(the people of Colorado
4300 Cherry Creek Dr. S. Laboratory and Ra.iiation Services Division
Denver, Colorado 80246-1530 8100 Lowry BWd.
Phone [phone] Denver CO 80220-6:'28
Located in Glendale, Colorado (3031 6923090
http:llwww.cdphe.sta u.m. us
January 8, 1998
Kimberley Wolf
Colowyo Coal Company
5731 State Highway 13
Meeker, Colorado 81641
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RE: Storm Water Exemption, Third Quarter DMR
CDPS Permit No. COG-850017, Outfalls 002A, 004A, 005A, 007A, 008A, 010A
Routt County
Dear Ms. Wolf:
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This letter is response to your letter dated December 9, 1997, in which you reported noncompliance
of effluent limits at Outfalls 002A, 004A, OOSA, 007A, 008A, and 010A due to a storm water event
during September 1997. Your letter described an exceptional rain event that occurred from
September 18 through September 22, 1997 during which an accumulation of precipitation was
recorded at various rain gauges at Colowyo Coal Company, resulting in discharges at the various
outfalls referenced above. The recorded rainfall from September 18 (0600 hours) through
September 19 (0600 hours), 1997 qualifies as a storm event greater than the 10-year/24-hour storm
level for all referenced outfalls, except OOSA. All outfalls, except 005A, are exempt from Total
Suspended Solids, Total Iron and Settleable Solids limitations. Precipitation recorded at Outfall
005A qualifies for a storm event less than the 10-year, 24-hour event, thus exempting you from only
Tolal Suspended Solids and Total Iron limitations. The self monitoring data you provided on your
Discharge Monitoring Report is shown below:
Outfall Reported Permit
Number Parameter Results Conditions
002A TSS (mg/l) 54 (30day avg) 35 (30day avg)
002A TSS (mg/I) 138 (daily mx) 70 (daily mx)
004A TSS (mg/I) 243 (30day avg) 35 (30day avg)
004A TSS (mg/I) 532 (daily mx) 70 (daily mx)
004A Iron, Total (mg/l) 44.9 (30 day avg) 3.5 (30 day avg)
004A Iron, Total (mg/I) 130 (daily mx) 7.0 (daily mx)
004A Solids, Settleable (mg/I) 1000 (daily mx) 0.5 (daily mx)
OOSA TSS (mg/I) 52 (30 day avg) 35 (30 day avg)
007A TSS (mg/I) 2175 (30 day avg) 35 (30 day avg)
007A TSS (mg/I) 8130 (daily mx) 70 (daily mx)
007A Solids, Settleable (mg/I) 160 (daily mx) 0.5 (daily mx)
007A Iron, Total (mg/I) 13.5 (30 day avg) 3.5 (30 day avg)
007A Iron, Total (mg/I) 50 (daily mx) 7.0 (daily mx)
008A TSS (mg/I) 3300 (30 day avg) 35 (30 day avg)
OOSA TSS (mgll) 6600 (daily mx) 70 (daily mx)
008A Solids, Settleable (mg/I) 35 (daily mx) 3.5 (daily mx)