2010-05-07_PERMIT FILE - C2009087 ‎(47)‎

• Permit No: C2009087
• IBM Index Class Name: Permit File
• Doc Date: 5/7/2010
• Doc Name: Stock Tank As Built Report
• Section_Exhibit Name: Exhibit 2.05.3-E2 Appendix 2.05.3-E2.I
• Media Type: D
• Archive: No

POND DIMENSTIONS
The dimensions and capacity of permanent stock ponds are shown on the attached stock pond as -built
draMn,s. As shuNrn, all embankments are loss than Ghe (5) fCUt ill IlQi"lit cw 111�d-ui�J 11011 tli'�
upstream toe of the dam to the invert of the emergency spillway. The combined slope of all the
embankments is less than 5H: IV with no slopes greater than 2H: IV. All the capacities are less than
two (2) acre -feet. All stock ponds have emergency spillways that consist of a single open channel.
None of their have a principal spillway or dewaterins pipe.
SPILLWAY CAPACITIES
The stock ponds were analyzed to determine if the spillways for the permanent stock ponds have the
capacity to safely pass the peak discharge from the 25 -year, 24 -hour storm event. In addition, rock
riprap requirements were also evaluated.
The peak discharge, spillway capacity and rock riprap requirements were determined using
SEDCAD4. The peak discharge was determined using the same methodologies and assumptions
outlined in the postmine channel SEDCAD demonstrations. A curve number of 71 was used for
this evaluation which represents a hydrologic soil group B with a fair herbaceous cover. All hydrology
inputs and results are shown on the attached SEDCAD4 computer printouts.
To determine spillway capacity, capacity tables were developed based on the existing spillway
dimensions using the pond subroutine in the SEDCAD model. The SEDCAD results are attached.
Using these tables and the peak flow from the 25 -year, 24 -hour sturm event, the depth ul tluw alld
freeboard were determined for each stock pond. The results, are shown on the table below.
Rock riprap requirements were determined using either the PADER or OSM method found in the
channel utility subroutine of the SEDCAD model. The results are summarized on the following
table.
s
STOCK POND SPILLWAY SUMMARY
Pond
25
Year
Flow
cfs
Bottom
Width
(ft)
Invert
Elev. of
Spillway
ft
Depth
of
Flow.
ft
Peak
Flow
Elev.
ft
Top of
Embankment
(ft)
Freeboard
(ft)
Riprap
Dso
(inches)
T -3
14.3
12
7,460.5
0.6
7,461.1
7,464.0
2.9
Ve
T -4
17.4
6
7,096.0
1.1
7,097.1
7,102.1
5.0
12
T -8
13.5
8
7,318.5
0.7
7,319.2
7,321.6
2.4
6
T -16
6.0
10
7,464.6
0.5
7,465.1
7,469.0
3.9
6
T- 17
12.5
20
7,135.0
0.4
7,135.4
7,138.0
2.6
9
T -20
6.4
20
7,202.0
0.4
7,202.4
7,204.3
1.9
6
T -26
32.2
18
7.333.3
0.9
7.334.2
7
7,505.0
2.2
1.6
9
9
T -28
24.4
20
7,502.6
0.8
7,503.4.
T -29
30.9
18
7,403.8
0.9
7,404.7
7,406.0
1.3
12
18
7,674.0
0.7
7,674.7
7,675.8
1.1
9
.9
15
7,818.0
0.8
7,818.8
7,820.3
1.5
6
g1 T-3019.0
.3
12
7,812.5
0.5
7,813.0
7,814.8
1.8
6
0.3
17
7,512.0 1
0.8
7,512.8
7,513.8
1.0
9
'I R --t6
Revised 09"08