WSP05772

• File Number: 8142.600.30.A
• Description: Other Studies - Purgatoire River Transit Loss Study
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 6/1/1953
• Author: Corps of Engineers
• Title: Review Report on Survey for Flood Control - Volume II
• Water Supply Pro - Doc Type: Report/Study

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39. Project design flood. - The design flood for Tri nidact Reset'voir
would have a peak discharge of 99,000 cubic feet per second and a volume
of 57,900 acre~feet. This is the same as the standard project flood

descri bed in the preceding paragraph. In comparison to the maximum flood

of record which occurred September 29-30, 1904, the standard project

flood at Trinidad is about 235 percent and 153 percent, respectively, of

the peak discharge and volume.

40. Flood control storage. ~ The reservoir storage required to con-

trol the major floods of record and the standard project flood is shown

in table 14. The flood control storage capacity required at Trinidad

Reservoir for the standard project flood developed for the drainage area
above the dam site is 46,700 acre~feet, or the equivalent.of 1.25 inches
of runoff. This is about 95 percent greater than the capacity required

for the maximum flood of record as indicated in table J4.

41. The flood control storage capacity was determined by routing

the standard project flood through the reservoir. Starting with the

reservoir full to the top of conservation pool )94,000 acre-feet), the
flood was regulated to control the outflow to 5,000 cubic feet per second

as long as possible. After the peak which would be produced by the stand-

ard project flood from the uncontrolled area between the dam site and

Trinidad occurred, releases were controlled to 15,000 cubic feet per second

until the peak reservoir level "as reached. Thereafter, outflows were

maintained equal to inflows until 5,000 cubic feet per second outflow was

reached. From this point, the flood control pool was emptied at the rate

of 5,000 cubic feet per second as long as possible.

42. The storage capacity required to control the maximum floods of

record was determined by routing these floods through the reservoir,

starting with the reservoir full at top of conservation pool. These

floods were regulated to control the flow at Trinidad to 5,000 cubic feet

per second whenever possible.

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APPENDIX B

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