2013-04-25_PERMIT FILE - C1981019A

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 4/25/2013
• Section_Exhibit Name: Exhibit 07 Methodologies & Assumptions for Sedimentation Pond Design Evaluations
• Media Type: D
• Archive: Yes

• Discharge flow basis for emergency spillway capacity evaluation (for a Class B pond):
• 100 -yr, 6 -hr peak flow + 0.12 (PMP, 6 -hr peak flow - 100 -yr, 6 -hr peak flow)
• Discharge flow basis for impoundment freeboard evaluation (for a Class B pond):
• 100 -yr, 6 -hr peak flow + 0.4 (PMP, 6 -hr peak flow - 100 -yr, 6 -hr peak flow)
TABLE 5
IMPOUNDMENT HAZARD ANALYSIS SUMMARY
IMPOUNDMENT
HAZARD
SPILLWAY
FREEBOARD
CLASSIFICATION/BASIS
CAPACITY
EVALUATION
EVALUATION
BASIS /RESULT/
BASISVRESULT
FREEBOARD
Streeter Pond (001A)
B /Proximity to State Highway
Class B /Ok
Class B /Ok/0.25'
13
Work Area Pond (002A)
A /Agricultural Land
Class B /Ok
Class B /Ok/1.55'
Gossard Pond (003A)
A/Agricultural Land
Class B /Ok
Class B/Ok/6.46'
Gulch A Pond (004A)
A /Agricultural Land
Class B /Ok
Class B /Ok/0.16'
Stoker Siding Pond
A/Agricultural Land
Class B /Ok
Class B/Ok/3.64'
(005A)
Rail Loop Pond (006A)
A/Agricultural Land
Class B /Ok
Class B /Ok/1.82'
Prospect Pond (007A)
B /Proximity to State Highway
Class B /Ok
Class B /Ok/0.61'
13
West Pit Pond (008A)
A/Agricultural Land
Class B /Ok
Class B/Ok/2.47'
Section 16 Pond (009A)
B /Proximity to State Highway
Class B /Ok
Class B/Ok/0.96'
13
East Taylor Pond (01OA)
A/Agricultural Land
Class B /Ok
Class B/Ok/0.76'
Taylor Pump Holding
A /Agricultural Land
Class B /Ok
Class B /Ok/0.91'
Pond
Notes: 1 Spillway capacity and freeboard for all ponds were evaluated for a uniform worst -case
hazard classification (Class B)
The results of the W WC impoundment hazard analysis indicate that emergency spillway capacities and
available freeboard for all existing ponds are adequate to affect full compliance with applicable
requirements under the guidelines of TR -60, based on the applicable hazard classifications. Given this
confirmation of compliance, no modifications to the existing emergency spillway structures are required.
5.0 POND DESIGN EVALUATION RESULTS
The results of the pond design analyses are summarized in Table 6. The supporting SEDCAD4 analyses
and watershed maps are presented as attachments in each of the individual pond design sections
Exhibit 7 Page 8 Revision Date: 3/18/13
Revision No.: TR -95