FLOOD06920

• County: Boulder
• Community: Jamestown
• Stream Name: James Creek
• Basin: South Platte
• Title: Community File
• Date: 1/1/2001
• Prepared For: CWCB
• Prepared By: CWCB
• Floodplain - Doc Type: Community File

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values on semi-logar .thOlic paper. Adjustments tor depth-area were based

on the depth-area re' ationship presented in the NOAA publication_ Adjust-

ments for length of ::ecord were made on logarithmic probability paper

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using Beard's 'table ,,[ expected probability adjustments for various lengths"

of record. The spatlal variation of the rainfall potential shown in the

Atlas for the Leftha:ld Creek basin was 'simulated by SWMl-l through the intro-

duction of several hyctographs. The time variat~on of the 3- and 6-hour

rainfall for each hyetograph was based on a study of hourly precipftation.

data recorded during major storms in the South Platte River basi"... -Time

intervals of 15- and 30-minutes were used in distributing the J- and 6-hour

rainfalls, respecti;vely. The 3- and 6-hour distribution is given in Table 1

below.

TABLE 1
RAINFALL DISTRIBUTION FOR J- AND 6-HOUR DURATIONS

3-Hour
End of Period
(Minutes)

6-Hour
End of Period
(l-linutes)

Incremental Rainfall
(Percent)

15
30
45
60
75
90
105
120
135
150
165
180

30
60
90
120
150
180
210
240
270
JOO
330
360

2
4
4
5
9
10
40
10
6
4
4
2

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