2007-10-30_PERMIT FILE - C1982057A ‎(3)‎

• Permit No: C1982057A
• IBM Index Class Name: Permit File
• Doc Date: 10/30/2007
• Section_Exhibit Name: Tab 20 Backfilling and Grading
• Media Type: D
• Archive: Yes

Channel stability was analyzed using the erodible channel sub-routine. The designs assume the
TRM is installed over bare soil. The channel roughness coefficient (i.e., Manning's n) and the
limiting velocity values were hand entered. Examples of manufacturer's published performance
values for select TRM products under bare soil conditions are summarizes in Table 4, Turf
Reinforcement Mat Performance Guide. Manufacturer's performance specifications for these
products are found in Attachment 20-C, Turf Reinforcement Mat Design and Installation Information.
To calculate the greatest potential instability (i.e., the highest velocity) SCC selected a roughness
coefficient value of 0.023, which is less than any of the manufacturer's published values. SCC
selected 10.0 feet per second as the limiting velocity value.
•
TABLE 4
Turf Reinforcement Mat Performance Guide `
Permissible Velocity Permissible Sheer Stress
Product Manufacturer Manning's "n" f s Ibs/ft2

Bare Soil Ve etated Bare Soil Ve etated
P300 North American Green 0.034 9.0 16.0 3.0 8.0
SC250 North American Green 0.040 9.5 15.0 3.0 10.0
C350 North American Green 0.041 10.5 20.0 3.2 12.0
P550 North American Green 0.041 12.5 25.0 4.0 14.0
CFP-12 Greenfix America 0.024 12.0 4.5
CPG 3000 Greenfix America 0.024 20.0 10.0
Enkamat Colbond Geosynethics 0.030 20.0 19.0 6.7 8.0
7010
Enkamat Colbond Geosynethics 0.030 20 19 11.2 9.0
7018
Enkamat Colbond Geosynethics 0.030 13.0 19.0 11.2 10.0
7020
Notes: 1) This is a select list of products, SCC may use another equivalent product if the performance
criteria meets the minimum standards.
2) The manufacturer's product-specific performance properities are documents in Attachment 20-
C, Turf Reinforcement Mat Design and Installation Information.
3 Mannin 's "n" values are based on bare soil conditions with a flow de th of 0.5 feet.
Channel capacity was analyzed using the vegetated channel sub-routine. The channel roughness
coefficient is automatically calculated by the model. The limiting velocity value was hand entered
(manufacturer's published limiting velocity values for the TRM products are summarized in Table 4).
The designs assume a mixed grass community, 11 - 24-inches tall, which corresponds to a "B"
retardance class, and results in a higher surface water elevation.
Postmine drainage channels at II-W lined with TRMs will be either three (3) or ten (10) feet wide. The
minimum channel designs for the TRM lined channels are summarized on Figure 20-1.3. SEDCAD4
demonstrations are presented in Attachment 20-1.
TR-59 17 Revised 08107