FLOOD05026

• County: Weld
• Community: Nunn
• Stream Name: Spring Creek
• Basin: South Platte
• Title: Hydrology Investigation for the Spring Creek Watershed
• Date: 5/1/1990
• Prepared For: Nunn
• Prepared By: USDA Soil Conservation Service
• Floodplain - Doc Type: Floodplain Report/Masterplan

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iiTIWION OF PRE:IPITATION .'-"IOOm'S 2>A-= 90 2'~'
------~ r. c"-= e>. 'I+-
24 HOUR PRECIPITATION 0h6'll '--
\\ Freq. MQp Fact.or Plot.t.ed Value 1/A.~6
(Yrs.) Value Value Used ~
2 j.7C> 0.88 /. 5tJ /. s-l'
5 ;).~ 0.96 d.lt 2.2.0
10 d"~- 0.99 2. {, z... 2.62 2-. -f~
25 3';).D 1.00 3.2p .! ' I? z.f1
50 .3.6~ 1.00 ;? to () ..3 ,~a ,3..5'r
100 4.tJb 1.00 4./TC 4.~(? J-1~
1.00
-
..-._- --....liIiit",.
10-DAY PRECIPITATION (Ref:Hy. PO-6, Rev. 2)

SfEP
1 Select 2 yr., 6 and 24 Hr. precipe from NOAA Maps.
2 yr., 6 Hr. /. -I- in.
2 yr., 24 Hr. /.7. in.

2 Select appropriate region from FiB. B-1.
Region ~ .

3 Esti~te 2 yr., I-Hr. precipe using appropriate equation in Tbl. E-l.
2 yr., I-Hr. /. t!J 4-. in. '

4 Estimate 2 yr., 10-Day precipe trom Fig. F-2.
2 yr., 10-Day 2.7 . in.

S Estimate 100 yr.+-2 yr., 10-Day Ratio from Fil. B-3.
100 yr.+- 2 yr., 10-Day Ratio. Z'3_-'- .

6 lfultiply 2yr., 10-Day precipe by ratio in step 5 to obtain
100 yr., lO-Day precipe
2 yr., lO-Day ~ in X Ratioz.j'f- b,3S-in. (100 yr., lO-Day)

7 Multiply 2yr., lO-Day precipe by .88 to convert to annual series.
2 yr., lO-Day 2.;7 in X .88 - 2.Y in (2 yr., lO-Day Ann. Ser.)
.

8 Plott 2 yr. and 100 yr. precipe on Log-Norl1lal Probability Paper
for other trequencies.

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