2015-09-09_PERMIT FILE - C1981019A ‎(3)‎

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 9/9/2015
• Doc Name: Attachment 1 to Attachment 12
• Section_Exhibit Name: Exhibit 07 Prospect Pond 007A
• Media Type: D
• Archive: Yes

•

COLOWYO COAL COMPANY
047A-PROSPECT
SEDIMENTATION POND SUMMARY
ORIaiNAI 1996 1998 2006 DIFFERENCE
CONFIGURATION STUDY STUDY DIFFERENCE STUDY 1988 TO 2008
ATER8HfD AREA {acres}:
Disturbed O.D 4.0 O.D 0.4
PoshniNng Tapsoited and Seeded 45.0 88.0 23.0 103,8 35.8
Pastmining Undtsturbad 211.3 191.5 -19.8 236.8 45.3
1.2 Year RaGamatkur 59.d 178.3 118.5 231.4 53.1
3+YearRectamaUan 465.6 312.8 -152.7 12$.9 -184.0
Total Area 781.3 750,7 -30.6 701.0 -49.7
POND PARAMETERS:
Bottom Elevation 6735.7 6735,7 6735.7 0,0 6734.0 -1.7
Principal Splttway Invert Elevation 6750,3 6748.8 8750.3 i.5 6750.3 0.0
EmergancySptitvraytnvertElevaBon 6751;6 8751.6 6751.6 0.0 6752.0 0,4
Tap of Emt~nkment 6754.0 6754.0 $754.4 4.0 8755.0 1.D
Storage votame Belaw Emergency SpilAvay (ac-ft} 5.26 5.26 5,30 0,04 8.1 0.8
Staraga Valumo Below Principal Sp[ikvay {ac•ft} 4.81 3.65 4.52 0.87 5.1 0.$
Principal SpilAuay Parameters:
Type Drop Inlet Drop Iniai Pert, Riser Perf. Riser
Riser Diameter (tn) 12.4 12.0 12.0 qA 12.0 0.0
Riser Hetgfit {ft} 8.7 7,2 8,7 1.5 8J 0,0
Barra) Diameter {trr) 12.0 12.0 12.0 0.0 12.0 0.0
Elevation of Pefaration{$) {ft) NIA NIA 6744.4 6744.0
Size of Perforation{s) (in} NIA NIA 4.D 4.0
Number of Portaraaons NIA NIA 2 2.0
Emergency Spillway Parameters:
Type
Trapezoidal
Trapezoidal
Trapezoidal
Trapezoidal
Dtamete€ ('us) N/A N!A NIA NIA
BottomWldth{tt} 12.0 12.4 12.0 0.0 12.0 0.0
t.angih {ft) 20..4 20.0 24.0 0,0 20.4 OA
Side Slapes'z'Hr1V {ft} 2,0 2,0 1.5 -4.5 1.5 0.4
HYDROLOGICJHYDRAULtG PARAMETERS:
Base F)aw Rates (cis} 2A4 0.43 -1.97 4.15 0.1
t0-Year, 2d-HOUrStorm Event:
i
8
1
8
0
0
1.8
0.0
Precipttattan {tn) .
7
2 .
4
3 .
1
6 3.2 =1.1
Runoff volume (ac-itT
Pdnclpai Sp±thway Peak Discharge {cis} ,
6.0 .
2.0 .
-4.4 1.5 -4.
Emergency Spiiiwey Peak Discharge (~} 4.0 4.0 0.0 4.0 0.4
Peak Surface Water Stage Elevattdrt {ft) 6751.3 6749.5 -1.8 8747.0 -2.5
25-Year, 24-Haur Storm Event:
2
3
2
3
0.4
2,3
0.0
Prectpttatton {in} .
4
5 .
8
3 2.9 8.3 0.0
RunoftVOlumo(ac-!t}
Principal Spillway Paak Discharge (cis} ,
6.9 .
d,5 -2.4 4.0 -0.5
Emergency Spillway Peak Discharge {cfs} 9.8 3A -8.8 0.0 -3.0
Peak Surface Water5tage Eiavatian (ft) 6752.1 6751.8 -0.3 6751.4 -0.4
Pond Fraebaard fl} 1.9 22 0,3 3.6 1.4
EOIMENT LOADING PARAMETERS:
Storm Predicted Peak Settiaf~e Conceniratlan {mltl) 4.00 4.00 0.0 0,00 a,0
Predicted Annual Sediment loading {ac-ft) 0.09 0.52 0.43 1.91 1.4
Available Sediment Storage Volume (aa-it} 0.76 D.76 0.00 1,41 0.7
Maximum Sediment Storage Elevation {ft} 6741.8 8741.6 6741.6 0.0 5741.6 0.0
Predicted Number cf Stara a Years 8.4 1.5 -7.0 0.7 -0.7
Exh. 7-PP-21 Revision Date: 2/1/06
Revision No.: TR-63