FLOOD09746

• County: Statewide
• Basin: Statewide
• Title: Colorado Statewide Drainage Floodplain Management Criteria Manual
• Date: 8/1/2002
• Prepared By: CWCB & WRC Engineering Inc
• Floodplain - Doc Type: Educational/Technical/Reference Information

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COLORADO STATEWIDE
DRAINAGE AND FLOODPLAIN MANAGEMENT CRITERIA MANUAL

Region of applicability"

South Platte, Republican,
Arkansas, and Cimarron River
Basins (1)

San Juan, Upper Rio Grande,
Upper Colorado, and Gunnison
River Basins and Green River
Basin below confluence with the
Yampa River (2)

Yampa and Green River Basins
above confluence of Green and
Yampa Rivers (3)

North Platte (4)

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Mean of Standard
Corr. No. of computed error of
Equation coelf. stations stn. valuee estimate
(inches) (inches)
Y, = 0.218 + 0.709[(X,)(Xdx.Jl 0.94 75 1.01 0.074
Y100= 1.897 + 0.439[(X,)<X.1X,ll
- O.ooaz .84 75 2.68 .317
Y, = :- 0.011 + 0.942 [(X,)(X,/x.Jl .95 86 0.72 .085
Y,,. = 0.494 + 0.755[(X,)0<a/x.Jl .90 85 1.96 .290

Y, = 0.019 + 0.711 [(X,)(X,/X,)]
+ O.OOU .82 98 0.40 .031
Y,,. = 0.338 + 0.670[0<a)(X,/X,)]
+ O.OOlZ .80 79 1.04 .141
Y. = 0.028 + 0.890[(X,)(X,/X,)] .93 90 0.60 .062
Y,,. = 0.671 + 0.757[O<alO<a/x.Jl
--'- O.003Z .91 88 1.71 .236

. Numbers In parentheses refer to geographic regions shown in figure 19. See text for more complete description.

List of variables
Y. = 2.yr 1.hr estimated value
Y,,. = 10o-yr 1.hr estimated value
x.. = 2.yr 6.hr value from precipitatlon.frequency maps
X, = 2.yr 24'hr value from preclpltation.frequency maPs
X, = 10o-yr 6.hr value from precipitatlon.frequency maps
X, = 10o-yr 24'hr value from preclpitatlon.frequency maps
Z = point elevetion In hundreds of feet

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VERSION: AUGUST 2002

Wff 9\lG1t-H;~NG. jNC.

REFERENCE:
NOAA ATLAS 2, VOL III, 1973

TABLE CH5-T102
EQUATIONS FOR ESTIMATING 1-HOUR RAINFALL
VALUES