PERMFILE109820

• Permit No: C1980001
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: MOFFAT PERMANENT IMPOUNDMENT
• Section_Exhibit Name: 4.6 APPENDIX 4.6-R
• Media Type: D
• Archive: No

• summary predicts that the peak stage will be 18.43 ft. From the SEDCAD+
Elevation-Area-Capacity-Discharge table, this peak stage equates to a depth of
flow through the emergency spillway of 0.53 feet. Additional assumptions and
routing results are shown on the attached SEDCAD+ computer printout.
Crest Elevation
Spillway Type
Straight Barrel Diameter
Barrel Length
Initial Pool Elevation
Maximum Pool Elevation
•
Crest Elevation
Spillway Type
Width
Spillway Side Slopes
Crest Length
Spillway Dimensions
Principle spillway-
The purpose of having a principal spillway for this impoundment is to
retain flood storage capacity. The existing principal spillway in the
Moffat sediment pond will be retained with it present specifications.
Major assumptions and results of flood routing are summarized below (all
elevations are relative to the constructed bottom of the pond; numbers in
parentheses are relative to the elevations above the sediment level).
Emergency Spillway-
The emergency spillway of the sediment pond will be retained at its present
specifications. The channel bottom and side slopes of the emergency
spillway will be maintained with rip-rap to ensure erosion control. Major
assumptions and the results of flood routing for the emergency spillway
design flood are summarized below (all elevations are relative to the
constructed bottom of the pond; numbers in parentheses are relative to the
elevations above the sediment level).
13.6 (7.0) feet
Trickle Tube
12 inches
76 feet
13.6 (7.0) feet
18.43 (11.63) feet
17.9 (11.3) feet
Open Channel
13 feet
3h:ly
28
Initial Pool Elevation
Maximum Pool Elevation
Maximum Discharge (1° & 2°)
u
Technical Revision 32
4.6R-2
13.6 (7 .0) feet
18.43 (11.83) feet
16.13 cfs
September 5, 1995