FLOOD04855

• County: Boulder
• Community: Boulder
• Stream Name: South Boulder Creek
• Basin: South Platte
• Title: Flood Hazard Area Delineation
• Date: 7/1/1986
• Prepared For: Boulder County
• Prepared By: UDFCD
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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FLOODING SOURCE 100 YR FLOODPLAIN DATA FLOODW4Y DATA 2
CROSS STATlONl Df~ '9L-' '(fl... THALWEG FLOOD FLOOD- FLOODWAY WIDTH FLOODWA Y'
IDENTIFICATION SEC'nOIl ~1j~'lGE ELEV. (m,$,I.) ELEV. (m.s./,) PLAIN LEFT (FEET) RIGHT (FEET) TOTAL (FEET) ELEV. fm.s./.J
I WIDTH7FEFT)
49220 492+20 4800 5710.8 5720.5 330 60 (60) 34 (34) 94 (94) 5720.6 (5720.6)
49505 495+05 4800 5716.3 5726.3 240 40 (40) 70 (70) 110 (110) 5726.3 (5726.3)
Bridge to Residences 49540 495+40 4800 5717.1 5726.3 260 40 (40) 59 (59) 99 (99) 5726.2 (5726.2)
49890 498+90 4800 5727.2 5734.5 75 25 (25 ) 47 (47) 72 (72) 5734.5 (5734.5)
50210 502+10 4800 5734.8 5744.9 75 32 (32) 35 (35 ) 67 (67) 5745.0 (5745.0)
50515 505+15 4800 5745 .5 5753.9 80 40 (40) 25 (25 ) 65 (65) 5754.1 (5754.l)
50860 508+60 4800 5756.9 5767.6 50 l8 (18) 32 (32) 50 (50) 5768.1 (5767.5)
51065 5l0+65 4800 5765.8 5776.7 50 20 (20) 30 (30) 50 (50) 5777.1 (5777.2)
Bridge 51129 511 +29 4800 5768.3 5778.1 50 25 (25 ) 25 (25 ) 50 (50) 5778.8 (5778.4)
Upstream study Limit 51260 512+60 4800 5772.2 5781.2 70 28 (28) 42 (42) 70 (70) 5782.3 (5781. 9)
DRY CREEK . 2 DITCH SPI TROW PROfIL
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Downsteam Study Limit 6445 34+80 4030 5210.l 5220.2 2880* 123 (217) 779 (937) 902 (1154 ) 5221.2 (5220.7)
3800 38+00 4030 52l6.3 5220.3 2270* 130 (130) 670 (845) 800 (975) 5221. 3 (5220.8 )
7170 43+50 4030 5220.4 5224.2 1120* 318 (318) 450 (500) 770 (8l8) 5224.3 (5224.2)
Downstream Side of 7590 47+30 4030 5225.2 5228.4 1950* 380 (440) 335 (360) 715 (800) 5228.6 (5228.6 )
Arapahoe Road 7701 49+50 2430 5225.6 5233.2 3280* 390 (390) 290 (290)** 680 (680) 5234.2 (5233.7)
5400 54+00 2300 5231.6 5233.4 2260* 250 (350) 190 (290) 440 (640) 5234.3 (5233.9)
6000 60+00 1900 5236.8 5237.9 2270* 260 (260) 205 (260) 465 (520) 5238.2 (5238.1)
6520 65+20 .1500 5241.3 5242.2 1950* 183 (300) l20 (250) 303 (550) 5343.0 (5242.7)
7050 70+50 1000 5246.0 5247.0 1320* 100 (lOO) 150 (180) 250 (280) 5247.4 (5247.2)
7305 73+50 300 5248.2 5249.4 410* 100 (100) 110 (160) 210 (260) 5249.7 (5249.6)
l0838 76+60 6630 5252.0 5253.6 *** *** *** *** ***

1 Stationing from mouth (feet).
2 Floodway data in parenthesis () represent floodway based on 0.5 ft rise in Energy Grade Line (EGL)- all other floodway data pertains to encroachment
for 1 foot rise in EGL- widths relative to channel centerline looking downstream.
* FloDdplain measured for Dry Creek split flow only.
** Arapahoe Road right-of-way to be considered as floodway limit.
***Upstream limit of split flow - see first page of this table for floodplain/floodway data.

GREENHORNE and O'MARA, INC.
Enginee" . Archilects ' Planners . Sur.eyors . PhologlllmmetriSls
IU5 ~ Cotatado aoutevcnt'Suite 405, Denver. Colorado 10222- (:$03) 758.5250

URBAN DRAINAGE AND FLOOD CONTROL DISTRICT
BOULDER COUNTY

IOO-YEAR FLOODPLAIN AND FLOODWAY
REFERENCE DATA
SOUTH BOULDER CREEK

TABLE
4
(ContJ

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