Compliance Summary Table for the Barker Draw NPDES permit WY0042102 ph Results at outfall 001 Associated with Barker Draw NPDES permit WY0042102 Status Outfall Date Sampled Constituent Permit Limit Concentration Lab Sample ID In 5/5/2002 8.8 s.u. G02050073-002 001 ph 6.5-8.5 s.u. Compliance 7/27/2002 7.5 s.u.* G02070512-004 *The exceedance was not verified. SAR Results at outfall 002 Associated with Barker Draw NPDES permit WY0042102 Status Outfall Date Sampled Constituent Permit Limit Concentration Lab Sample ID In 3/1/2002 12.8 G02030015-001 002 SAR, unitless 6, unitless* Compliance 5/5/2002 No Flow at POC. N/A *This limit is established at the POC and flow was not reaching that point. This was not an exceedance. Dissolved Iron Results at outfall 003 Associated with Barker Draw NPDES permit WY0042102 Status Outfall Date Sampled Constituent Chapter 1 Limit Concentration Lab Sample ID In 3/26/2003 1300 ug/l G03030280-001 003 Fe, dissolved 1000 ug/l Compliance 12/12/2003 ND (<30 ug/l)* G03120190-001 *The exceedance was not verified. Total Barium Results at outfall 005 Associated with Barker Draw NPDES permit WY0042102 Status Outfall Date Sampled Constituent Chapter 1 Limit Concentration Lab Sample ID In 2/7/2002 690 ug/l G02020090-002 005 Ba, total 400 ug/l* Compliance 5/5/2002 No flow at POC N/A *This limit is established at the POC and flow was not reaching that point. This was not an exceedance. SAR Results at outfall 005 Associated with Barker Draw NPDES permit WY0042102 Status Outfall Date Sampled Constituent Permit Limit Concentration Lab Sample ID In 2/7/2002 12.8 G02020090-002 005 SAR, unitless 6, unitless* Compliance 5/5/2002 No flow at POC N/A *This limit is established at the POC and flow was not reaching that point. This was not an exceedance.
Compliance Summary Table for the Barker Draw NPDES permit WY0042102 ph Results at outfall 005 Associated with Barker Draw NPDES permit WY0042102 Status Outfall Date Sampled Constituent Permit Limit Concentration Lab Sample ID In 4/26/2004 8.58 G04040676-001 005 ph, s.u. 6.5-8.5 s.u. Compliance 5/19/2004 8.21* G04050505-001 *The exceedance was not verified. Total Recoverable Aluminum Results at outfall 008 Associated with Barker Draw NPDES permit WY0042102 Status Outfall Date Sampled Constituent Chapter 1 Limit Concentration Lab Sample ID In Al, total *no record of initial exceedance. 008 750 ug/l Compliance 11/11/2002 recoverable 540 ug/l* G02110112-001 *The exceedance was not verified. Total Recoverable Aluminum Results at outfall 009 Associated with Barker Draw NPDES permit WY0042102 Status Outfall Date Sampled Constituent Chapter 1 Limit Concentration Lab Sample ID No data *no record of initial exceedance. In Al, total 009 9/11/2002 750 ug/l 820 ug/l G02090118-002 Compliance recoverable 9/28/2002 560 ug/l G02090288-001 *The exceedance was not verified. Total Recoverable Arsenic Results at outfall 009 Associated with Barker Draw NPDES permit WY0042102 Status Outfall Date Sampled Constituent Chapter 1 Limit Concentration Lab Sample ID In 4/26/2004 As, total 9.7 ug/l G04040676-002 009 7 ug/l Compliance 5/19/2004 recoverable 1.6 ug/l G04050505-003 *The exceedance was not verified. Total Barium Results at outfall 009 Associated with Barker Draw NPDES permit WY0042102 Status Outfall Date Sampled Constituent Chapter 1 Limit Concentration Lab Sample ID In 4/26/2004 2500 ug/l G04040676-002 009 Ba, total 1800 ug/l Compliance 5/19/2004 891 ug/l G04050505-003 *The exceedance was not verified.
Compliance Summary Table for the Barker Draw NPDES permit WY0042102 Total Recoverable Aluminum Results at outfall 010 Associated with Barker Draw NPDES permit WY0042102 Status Outfall Date Sampled Constituent Chapter 1 Limit Concentration Lab Sample ID In no data Al, total *no record of initial exceedance. 010 750 ug/l Compliance 9/28/2002 recoverable 180 ug/l G02090288-003 *The exceedance was not verified. Dissolved Iron Results at outfall 010 Associated with Barker Draw NPDES permit WY0042102 Status Outfall Date Sampled Constituent Chapter 1 Limit Concentration Lab Sample ID 2/27/2003 2500 ug/l G04040676-002 12/3/2003 891 ug/l* G04050505-003 In Compliance 010 4/26/2004 Fe, dissolved 1000 ug/l 3980 ug/l** G04040676-003 5/19/2004 1960 ug/l G04050505-002 8/24/2004 ND (<30 ug/l)*** G04080504-001 *The exceedance was not verified. A compliance letter was submitted. **The exceedance showed up again during 2004 annual sampling. ***This compliance sample was collected post-refurbishment.
Barker Draw Area Watersheds Pennaco Energy, Inc. Storm Runoff Calculations using SCS and HEC-HMS WY0042102 Soils C CN = 75 Ia = 0.666666667 in. Watershed Watershed Area Hydraulic Length of Watershed Basin Slope (%) Time of Concentration SCS Lag Time Reservoir Volume Precipitation Calculated Runoff Volume from Event (sq mi) (feet) (hours) (hours) (acre-ft) (acre-ft) Barker Draw ICP-1 33.37 79,337 15.83 2.94953 1.7697 43.02 Instream LX Bar Creek Water Quality Precip 25yr-24hr 2.9 in 1506.20 Na Mg Ca EC Precip 10yr-24hr 2.5 in 1088.50 mg/l mg/l mg/l umhos/cm Precip 2yr-24hr 1.5 in 271.27 47 27 12 946 Barker Draw ICP-2 7.35 34,221 15.97 1.49550 0.8973 65.42 Precip 25yr-24hr 2.9 in 341.62 Precip 10yr-24hr 2.5 in 247.47 CBM Water from NPDES Permit WY0042102-006 Precip 2yr-24hr 1.5 in 62.56 Na Mg Ca EC mg/l mg/l mg/l umhos/cm 315 10 19 1430
Barker Draw Specific Conductance Mixing Calculations Pennaco Energy, Inc. WY0042102 Instream LX Bar Creek Water Quality EC umhos/cm 946 2-Year Storm Mix Runoff Water CBM Water from NPDES Permit WY0042102-006 Resultant Concentrations for 2-year event CBM Water Runoff Water Produced 2-Year Storm Volume Volume Drainage EC EC Resultant EC mg/l (acre-feet) (acre-feet) Barker Draw ICP-1 946 1430 1012 43.02 271.27 Barker Draw ICP-2 946 1430 1193 65.42 62.558 10-Year Storm Mix Runoff Water CBM Water from NPDES Permit WY0042102-006 Resultant Concentrations for 10-year event CBM Water Runoff Water Produced 10-Year Storm Volume Volume Drainage EC EC Resultant EC mg/l (acre-feet) (acre-feet) Barker Draw ICP-1 946 1430 964 43.02 1088.5 Barker Draw ICP-2 946 1430 1047 65.42 247.47 25-Year Storm Mix Runoff Water CBM Water from NPDES Permit WY0042102-006 Resultant Concentrations for 25-year event CBM Water Runoff Water Produced 25-Year Storm Volume Volume Drainage EC EC Resultant EC mg/l (acre-feet) (acre-feet) Barker Draw ICP-1 946 1430 959 43.02 1506.2 Barker Draw ICP-2 946 1430 1024 65.42 341.62
Barker Draw SAR Mixing Calculations Pennaco Energy, Inc. WY0042102 Instream LX Bar Creek Water Quality Na Mg Ca mg/l mg/l mg/l 47 27 12 2-Year Storm Mix Runoff Water CBM Water from NPDES Permit WY0042102-006 Resultant Concentrations for 2-year event CBM Water Runoff Water Drainage Na Mg Ca Na Mg Ca SAR Na Mg Ca Na Mg Ca SAR Na Mg Ca Na Mg Ca Resultant SAR Produced Volume 2-Year Storm Volume mg/l mg/l mg/l meq/l meq/l meq/l mg/l mg/l mg/l meq/l meq/l meq/l mg/l mg/l mg/l meq/l meq/l meq/l (acre-feet) (acre-feet) Barker Draw ICP-1 47 27 12 2.0 2.2 0.6 1.72 315 10 19 13.7 0.8 0.9 14.6 84 25 13 3.6 2.0 0.6 3.1 43.02 271.27 Barker Draw ICP-2 47 27 12 2.0 2.2 0.6 1.72 315 10 19 13.7 0.8 0.9 14.6 184 18 16 8.0 1.5 0.8 7.5 65.42 62.558 10-Year Storm Mix Runoff Water CBM Water from NPDES Permit WY0042102-006 Resultant Concentrations for 10-year event CBM Water Runoff Water Drainage Na Mg Ca Na Mg Ca SAR Na Mg Ca Na Mg Ca SAR Na Mg Ca Na Mg Ca Resultant SAR Produced Volume 10-Year Storm Volume mg/l mg/l mg/l meq/l meq/l meq/l mg/l mg/l mg/l meq/l meq/l meq/l mg/l mg/l mg/l meq/l meq/l meq/l (acre-feet) (acre-feet) Barker Draw ICP-1 47 27 12 2.0 2.2 0.6 1.72 315 10 19 13.7 0.8 0.9 14.6 57 26 12 2.5 2.2 0.6 2.1 43.02 1088.5 Barker Draw ICP-2 47 27 12 2.0 2.2 0.6 1.72 315 10 19 13.7 0.8 0.9 14.6 103 23 13 4.5 1.9 0.7 3.9 65.42 247.47 25-Year Storm Mix Runoff Water CBM Water from NPDES Permit WY0042102-006 Resultant Concentrations for 25-year event CBM Water Runoff Water Drainage Na Mg Ca Na Mg Ca SAR Na Mg Ca Na Mg Ca SAR Na Mg Ca Na Mg Ca Resultant SAR Produced Volume 25-Year Storm Volume mg/l mg/l mg/l meq/l meq/l meq/l mg/l mg/l mg/l meq/l meq/l meq/l mg/l mg/l mg/l meq/l meq/l meq/l (acre-feet) (acre-feet) Barker Draw ICP-1 47 27 12 2.0 2.2 0.6 1.72 315 10 19 13.7 0.8 0.9 14.6 54 27 12 2.4 2.2 0.6 2.0 43.02 1506.2 Barker Draw ICP-2 47 27 12 2.0 2.2 0.6 1.72 315 10 19 13.7 0.8 0.9 14.6 90 24 13 3.9 2.0 0.7 3.4 65.42 341.62
NDPES Permit Renewal Application Pennaco Energy, Inc. LS Draw - Spotted Horse WY0039721 HUC - 1009020209 March 11, 2004 Page 21 of 25