2011-12-16_REVISION - M1977572 ‎(71)‎

• Permit No: M1977572
• IBM Index Class Name: REVISION
• Doc Date: 12/16/2011
• Doc Name: Submittal
• From: VALCO
• To: DRMS
• Type & Sequence: TR2
• Media Type: D
• Archive: No

Scenario Description
Max. Q
Normal Storm
(no tailwater)
2 -Year (with
tailwater)
10- Year
(with
tailwater)
50- Year
(with
tailwater)
100- Year
(with
tailwater)
Input and Results from North American Green
ECMDS Version 4.3
Inlet Discharge (cfs)
300
2,630
6,759
19,235
27,455
Bottom Width (ft)
300
300
300
300
300
Side Slopes (H:1V)
3
3
3
3
3
Slope (ft/ft)
0.2
0.00038*
0.00038*
0.00068*
0.00088*
Velocity (ft /s)
4.3
3.7
5.3
9.7
12.0
Area (ft
70
714
1276
1974
2310
Hydraulic Radius (ft)
0.2
2.3
3.9
5.8
6.7
Depth (ft)
0.2
2.3
4.1
6.2
7.2
Mat Type
P550
P550
P550
P550
P550
Vegetation (Un /Partial /Fully)
Unvegetated
Unvegetated
Unvegetated
Unvegetated
Unvegetated
Permissible Shear Stress (Ib /ft
3.3
3.3
3.3
3.3
3.3
Calculated Shear Stress (Ib /ft2)
1.4
0.1
0.1
0.3
0.4
Safety Factor
(Permissible /Calculated)
2.3
64.0
36.0
12.4
8.2
Remarks
Stable
Stable
Stable
Stable
Stable
HEC -RAS Model Spillway
Hydraulics
Velocity (ft/s)
3.2
3.8
5.4
9.3
12.0
Area (ft
95
697
1258
2228
2737
Hydraulic Radius (ft)
0.3
2.2
3.8
5.2
5.9
Depth (ft)
0.3
2.3
4.0
6.2
6.9
Shear Stress (Ib /ft
0.5
0.4
0.6
1.8
2.8
Safety Factor
(Permissible /HEC -RAS Shear)
6.4
8.6
5.1
1.9
1.2
Analysis of the Berm A inlet with NAG's P550 TRM was conducted for several hydraulic
conditions using North American Green's Erosion Control Materials Design Software Version 4.3. The
analysis was run for five different scenarios including a range of discharges and tailwater conditions.
Analysis results are provided in Appendix E.1. All analyses were run assuming that the P550 mat is in an
unvegetated condition. As TRMs become vegetated their stability increases. Therefore, running the
unvegetated analysis is a conservative assumption reflective of conditions for a period of time following
construction. However, the establishment of a healthy stand of vegetation is crucial to the long term
performance of the TRM. Table 4.1 provides the inputs and results of the TRM analysis. Also included in
the table are hydraulic calculations provided by the HEC -RAS hydraulic model in order to compare with
the ECMDS results. In all scenarios, an unvegetated P550 mat was found to be stable with safety factors
calculated by the ECMDS and manually using HEC -RAS results ranging from 1.6 to 96 and 1.4 to 11.6,
respectively. As the mat becomes vegetated, the safety factors will increase.
Table 4.1 Results of Hydraulic Analysis of Berm A Inlet with NAG P550 TRM
* Slope entered into NAG program to give similar hydraulic conditions computed by HEC -RAS model
COVALCOO1_Phase 11 Report_082211.docx
4.3 ANdERSON CONSU(TINq ENGiNEERS, INC.