2007-10-30_PERMIT FILE - C1982057

• Permit No: C1982057
• IBM Index Class Name: Permit File
• Doc Date: 10/30/2007
• Doc Name: Drainge and Sediment Control Plan II-W South Extension
• Section_Exhibit Name: Tab 13 Attachment 13-5B
• Media Type: D
• Archive: No

January 2002 Seneca II-lY/ Soutb E.x~an.rion * Drainage and Sediment Control Plan • Page 7
•

•
TABLE 5
SENECA II-W (SOUTH EXPANSION)
SEDIMENT POND DESIGN SUMMARY
POND 15 POND 16 POND 16A POND 17
WATERSHED AREA (acres):
Disturbed 39.3 315.7 314.0 80.3
Undisturbed 367.4 69.1 64.0 878.3
Total Area 406.7 384.8 378.0 958.6
POND PARAMETERS:
Bottom Elevation (ft msl)
7378.0
7446.0
7505.0
7375.0
Principal Spillway Invert Elevation (ft msl) 7390.0 7460.3 7525.0 7391.9
Emergency Spillway Invert Elevation (ft msl) 7391.8 7466.5 7527.5 7393.4
Top of Embankment (ft msl) 7394.0 7469.4 7530.0 7395.0
Storage Volume Below Principal Spillway (ac-ft) 3.62 6.90 16.13 8.12
Storage Volume Below Emergency Spillway (ac-ft) 4.71 12,82 20.03 9.74
Principal Spillway Parameters:
Drop Inlet
Drop Inlet
Drop Inlet
Drop Inlet
Type
Hole Elevation (if applicable) (ft msl) N/A N/A N/A NIA
Riser Diameter (in) 18 24 48 36
Riser Height (ft) 5.0 2.5 3.0 4.9
Barrel Diameter (in) 18 Y4 48 36
Emergency Spillway Parameters:
Trapezoidal
Trapezoidal
Trapezoidal
Trapezoidal
Type
Bottom Width (ft) 10 20 50 20
Length (ft) 60.0 36.0 28.8 24.6
Side Slopes H:1V 2.0/5.0 3.0 3.0 3.0
HYDROLOGIC/HYDRAULIC PARAMETERS:
10-year, 24-hour Storm Event:
7
1
7
1
1.7
Precipitation (in) 1,7
3
65 .
18.83 .
18.59 6.14
Runoff Volume (ac-ft)
Principal Spillway Peak Discharge (cfs) .
11.1 36.6 94.9 41.4
Emergency Spillway Peak Discharge (cfs) 0.0 0.0 0.0 0.0
Peak Surface Water Stage Elevation (ft msl) 7391.7 7466.2 7527.5 7393.4
25-year, 24-hour Storm Event: 2
1 2.1 2.1
Precipitation (in) 2.1
5
g0 ,
27.01
26.72
9.45
Runoff Volume (ac-ft) ,
0
0 40.3 110.9 48.5
Principal Spillway Peak Discharge (cfs) . 5
42 7
80 6.7
Emergency Spillway Peak Discharge (cfs) 28.4 .
5
7467 .
3
7528 7393.9
Peak Surface Water Stage Elevation (ft msl) 7392.9 . .
Pond Freeboard (ft) 1.05 1.9 1.6 1.1
SEDIMENT LOADING PARAMETERS: See Note 1
Storm Predicted Peak Settleable Concentration 67
4 0
00
(ml/I)
Predicted Annual Sediment Loading (ac-ft) 0.00
1.21 0.00
3.11 .
12.37 .
2.56
Available Sediment Storage Volume (ac-ft) 3.62 6.12 12.37 8.12
Maximum Sediment Storage Elevation (ft msl) 7390.0 7459.3 7522.2 7391.9
Predicted Number of Storage Years 3.0 2.0 1.0 3.2
Notes: 1. Pond 16A and Pond 16 are in series, with Pond 16A being the upper pond in sequence and Pond 16
bein the lower ond.
hlit%H * 165 S. Uuion Boulevarri, Suite 410 * Lakewood, Colorado 80228 * [phone]
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