PERMFILE123657

• Permit No: C1980005
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: SEDIMENTATION PONDS SEDIMENT STORAGE SURVEY
• Section_Exhibit Name: TAB 07 APPENDIX 7-11A
• Media Type: D
• Archive: No

• Sedimentation Pond 008. Design information and calculations for this pond were submitted
in the 4/6/87 Technical Revision No. 12 and subsequently approved by CMLRD. In 1987,
Sedimentation Pond 008 was surveyed as part of Se neca's annual sediment survey. The
survey information was utilized to develop a contour map. This data was used to calculate
the sediment storage beneath the principal spillway.
Following is a comparison of the design and the 1987 annual survey volume calculations:
4/16/87 Design (1987) Survey
Capacity Cumulative Capacity Capacity Cumulative Capacity
Elevation (Ac-Ft) (Ac-Ft) (Ac-Ft) (Ac-Ft)

7002 0 0 0 0
7004 0.13 0.13 0.42 0.42
7006 0.47 0.60 1.12 1.54
7008 1.04 1.64 1.86 3.40
7010 2.01 3.65 2.56 5.96

7011.0 1.39 5.04 - -

7011.4 - - 2.20 8.16
•
7014 5.28 10.32 5.53 13.04
7015 2.14 12.46 2.14 15.18
7016 2.32 14.76 2.29 17.46
7018 5.21 19.99 5.05 22.51
7019.1 - - - -
Elevation 7011,0 was the design principal spillway design elevation; whereas, Elevation
7011,4 is the existing principal spillway elevation.
At the principal spillway elevation of 7011.4, the pond can store 6.16 ac-f t. of sediment.
Based on the design:
(1) year of USLE generated sediment volume equals to 1.8 acre-feet/year. The
minimum sediment storage required equals 3.3 acre-feet.
Based on the 1987 annual sediment survey, the equivalent sediment storage of approximately
• 4.5 years of sediment runoff could be stored beneath the principal spillway elevation. At
7-11A-9