2022-04-04_PERMIT FILE - M2022013 ‎(38)‎

• Permit No: M2022013
• IBM Index Class Name: Permit File
• Doc Date: 4/4/2022
• Doc Name Note: Exhibit G - Flood Control Mitigation Plan
• Doc Name: Application
• From: Varra Companies, Inc.
• To: DRMS
• Email Name: RDZ
• Email Name: MAC
• Media Type: D
• Archive: No

Two Rivers Gravel Pit Mine
Riverside Berm Failure Analysis
and Flood Control Mitigation Plan
7ech"olooicess January 22,2020
Length Wtd. (ft) 2034.00 Wetted Per. (ft) 525.54 275.03 147.80
Min Ch El (ft) 4677.00 Shear(lb/sq ft) 0.14 0.23 0.07
Alpha 1.22 Stream Power(lb/ft s) 0.29 0.76 0.08
Fran Loss (ft) 2.60 Cum Volume (acre-ft) 65.91 53.43 5.15
C & E Loss (ft) 0.02 Cum SA (acres) 25.68 12.37 3.45
Warning: The cross-section end points had to be extended vertically for the computed water surface.
Warning: The conveyance ratio (upstream conveyance divided by downstream conveyance)is less than 0.7 or greater than
1.4. This may indicate the need for additional cross sections.
Warning: The energy loss was greater than 1.0 ft(0.3 m). between the current and previous cross section. This may indicate
the need for additional cross sections.
Note: Multiple critical depths were found at this location. The critical depth with the lowest, valid, energy was used.
CROSS SECTION OUTPUT Profile#50-yr
E.G. Elev (ft) 4685.72 Element Left OB Channel Right OB
Vel Head (ft) 0.23 Wt. n-Val. 0.040 0.035 0.040
W.S. Elev (ft) 4685.49 Reach Len. (ft) 2034.00 2034.00 2034.00
Crit W.S. (ft) 4682.35 Flow Area (sq ft) 2683.66 1957.99 612.87
E.G. Slope (ft/ft) 0.000834 Area (sq ft) 2683.66 1957.99 612.87
Q Total (cfs) 18600.00 Flow(cfs) 8515.93 8883.75 1200.33
Top Width(ft) 1048.38 Top Width (ft) 525.00 275.00 248.38
Vel Total (ft/s) 3.54 Avg. Vel. (ft/s) 3.17 4.54 1.96
Max Chl Dpth (ft) 8.49 Hydr. Depth(ft) 5.11 7.12 2.47
Conv. Total (cfs) 644075.4 Conv. (cfs) 294887.0 307623.9 41564.6
Length Wtd. (ft) 2034.00 Wetted Per. (ft) 527.52 275.03 248.45
Min Ch El (ft) 4677.00 Shear(lb/sq ft) 0.26 0.37 0.13
Alpha 1.17 Stream Power(lb/ft s) 0.84 1.68 0.25
Fran Loss (ft) 2.91 Cum Volume (acre-ft) 111.29 75.84 14.44
C & E Loss (ft) 0.03 Cum SA (acres) 25.68 12.61 6.00
Warning: The cross-section end points had to be extended vertically for the computed water surface.
Warning: The conveyance ratio (upstream conveyance divided by downstream conveyance)is less than 0.7 or greater than
1.4. This may indicate the need for additional cross sections.
Warning: The energy loss was greater than 1.0 ft(0.3 m). between the current and previous cross section. This may indicate
the need for additional cross sections.
Note: Multiple critical depths were found at this location. The critical depth with the lowest, valid, energy was used.
CROSS SECTION OUTPUT Profile#100-yr
E.G. Elev (ft) 4686.68 Element Left OB Channel Right OB
Vel Head (ft) 0.28 Wt. n-Val. 0.040 0.035 0.040
W.S. Elev (ft) 4686.39 Reach Len. (ft) 2034.00 2034.00 2034.00
pg. 51