2013-08-09_PERMIT FILE - C1996083A ‎(7)‎

• Permit No: C1996083A
• IBM Index Class Name: Permit File
• Doc Date: 8/9/2013
• Doc Name: Pages EXH 8-1 to EXH 8-97
• Section_Exhibit Name: Volume III Exhibit 08 Protection of The Hydrologic Balance
• Media Type: D
• Archive: Yes

PROTECTION OF THE HYDROLOGIC BALANCE
POND D
STORM EVENTS
10 YEAR 24 HOUR EVENT 1.8 INCHES
25 YEAR 24 HOUR EVENT 2.1 INCHES
100 YEAR 24 HOUR EVENT 2.6 INCHES
The information presented for the 25 -year event peak flow calculations is developed
with the use of SEDCAD. The output data from SEDCAD is on page Exh -8 -207 & 208.
The upland run -off areas are shown on Map No. 20 in Volume II. The run -off
curve numbers are developed based upon vegetation and soil types. Vegetation
data are presented in Volume III Exhibit 5 and shown on Map 3 in Volume II.
Soils data are presented in Volume III Exhibit 7 and shown on Map 4 in Volume II.
Ditches culverts and drainage plans are shown on Map 15 -3.
CURVE NUMBERS
Coal Mine Waste
Table 2 -2d -Runoff curve numbers for arid and semiarid rangelands
Cover Type - Herbaceous - mixture of grass, weeds and brush
Hydrologic Condition Poor
Soil Type D
Curve Number 90
Disturbed -Poor
Table 2 -2d -Runoff curve numbers for arid and semiarid rangelands
Cover Type - Herbaceous - mixture of grass, weeds and brush
Hydrologic Condition Poor
Soil Type - Loam C
Curve Number 87
Disturbed -Good
Table 2 -2d -Runoff curve numbers for and and semiarid rangelands
Cover Type - Herbaceous - mixture of grass, weeds and brush
Hydrologic Condition Good
Soil Type - Loam C
Curve Number 74
Disturbed -Fair
Table 2 -2d -Runoff curve numbers for and and semiarid rangelands
Cover Type - Herbaceous - mixture of grass, weeds and brush
Hydrologic Condition - -- — Fair
Soil Type - Loam C
Curve Number 81
RUN -OFF VOLUME - - Pond D (NRCS /SCS Runoff Equation)
Precip Direct Run -off
Area Acres Curve # Amount Run -off Vol A -F
Disturbed -Poor 0.81
Disturbed -Good 1.60
87 1.8
74 1.8
0.75 0.05
0.26 0.03
TR -76 Exh. 8 -17 12/12