2017-09-26_HYDROLOGY - C1981019

• Permit No: C1981019
• IBM Index Class Name: Hydrology
• Doc Date: 9/26/2017
• Doc Name: Quarterly Sediment Pond/Impoundment Report
• From: Tri-State Generation and Transmission Association, Inc
• To: DRMS
• Annual Report Year: 2017
• Report Quarter_Month: 3
• Permit Index Doc Type: Sediment Pond Inspections
• Email Name: ZTT
• Email Name: JRS
• Media Type: D
• Archive: No

Colowyo Coal Company L.P.
Permit No. C-1981-019
Annual Impoundment Inspection - Small Impoundments/Stockponds
Impoundment Name
Erosion, Instability,
Structural Weakness,
Hazardous Conditions
4.05.9 (15)(a)
Monitoring procedures
and Instrumentation
4 05 9 (15)(b)
Depth of
Impounded Waters
4.05 .9 15 c
Elevation of
Impounded Waters*
4.05 9 (15)(c)
Existing Storage
Capacity**
4 05.9 15 d
Other Structural
Instability or Maint.
Required
4 05.9 iirv.i
Experienced
Impoundment
Ins actor 4.05.9 14
Date
Of
Inspection
Stock Pond G
None
Annual Inspections
18 in.
7791.0 ft.
0.278 ac -ft.
None
Lee Sampson
9/26/2017
Stock Pond H
None
Annual Inspections
Dry
7870.0 ft.
0.219 ac -ft.
None
Lee Sampson
9/26/2017
Stock Pond i
None
Annual Inspections
Dry
7821.5 ft.
0.036 ac -ft.
None
Lee Sampson
9/26/2017
Stock Pond J
None
Annual Inspections
Temporarily covered by topsoil stockpile
Lee Sampson
9/26/2017
Stock Pond K
None
Annual Inspections
Dry
7889.0 ft.
0.990 ac -ft.
None
Lee Sampson
9/26/2017
• Moment in time measurement of the elevation of the top of the captured pool of water within the pond.
**Impoundments volumes are estimated from pre-existing as -built surveys and estimates of accumlated sediment.
I am a Licensed Professional Engineer in the State of Colorado. The information contained in this document was provided.
by Colowyo Coal L P Being familiar with the Colowyo operation, and relying on the information provided to me by
Colowyo Personnel, the information contained herein is reasonable and correct to the best of my knowledge and 47031
experience
g-21,--17