FLOOD02983

• County: Arapahoe
• Community: Littleton
• Stream Name: Lee Gulch, Little Creek
• Basin: South Platte
• Title: Major Drainageway Planning
• Date: 9/1/1978
• Prepared For: Littleton
• Prepared By: UDFCD
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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P~ESENT FUTURE DEVELOPMENT
HYDRO- TRIBU- DE\~, "...n'
TABLE I LOGIC LOCATION TARY 100 YR,STORM 100 YR. STORM 10 YR. STORM 5 YR. STORM
POINT AREA
HYDROGRAPH PARAMETERS ( ACRES) Qp Vol Qp Vol Qp Vol Qp Vol
(ets) (ae-fl) (cfs) (ac-ft) (ch) (ae-ft ) (cfs) (oe- ftl
Length to LEE GULCH
Sub- Area Length Centroid Slope % C C
Basin (Sq.M:i.) (Mi.) (Mi.) (%) Imp. t p 4000 COUNTY LI NE ROAD 125. 0 355 21 501 27 386 20 247 13
LEE GULCH 300 Oil WEST OF BROADWAY 991.0 1015 173 1682 233 1328 172 967 124
1000 0.40 1.52 0.76 1.2 31 0.54 0.66
2000 0.63 1.33 0.66 2.6 36 0.45 0.62 2000 WINDERMERE 1395.0 1475 251 2232 316 1724 231 1167 164
3010 0.72 1.61 0.83 2.6 47 0.37 0.56
3020 0.27 1. 21 0.59 3.1 67 0.27 0.49 1000 SO. PLATTE RIVER 1650.0 1744 301 2498 368 1840 267 1259 188
3030 0.40 0.99 0.33 0.1 74 0.53 0.66
4000 0.20 0.59 0.21 3.9 41 0.39 0.58
LI TTLE CREEK
LITTLE CREEK
100 0.12 0.64 0.26 1.0 95 0.23 0.46 500 E. DRY CREEK ROAD 186.6 521 36 624 39 478 28 30'; 20
200 0.62 1.48 0.78 1.2 39 0.45 0.62 4001)
300 0.83 1.33 0.52 1.6 45 0.40 0.59 HIGHLINE CANAL 741 . 1 1279 151 1440 160 983 116 627 81
410 0.57 1.28 0.52 1.9 42 0.43 0.61
420 0.30 0.97 0.47 2.1 52 0.36 0.56 300 GALLUP 1274.8 2077 262 2219 275 1555 199 979 139
500 0.29 0.80 0.28 2.7 41 0.41 0.59
200 R. R. TRACKS 1672.4 2702 344 2702 358 1916 259 1209 180
NOTE: Parameters are based upon future land use. SO PLATTE RIVERZl
100 1749.8 2742 364 2742 379 1943 274 1013 )191

STORM ROUTING

NOTES:

The hydrographs for the 5, 10 and 100-year storms were combined and

1. SU88ASIN 3010, 3020. ANO 3030 COMBINE AT POINT 3000. SU88ASINS 410 ANO 420
COMBINE AT POINT 400. ALL FLOWS CROSS HIGHLINE CANAL AT THESE POINTS SPILLING
SIDE SU8BASIN DRAINAGE.

2. SOME STORM RUNOFF CROSSES LITTLE CREEK 8ASIN BOUNDARY AT R.R. TRACKS, ALAMO, CHURCH
STREET AND INTERSECTION OF 80WLES AND SANTA FE.

routed through the drainageway. The Convex Method of Channel Routing, as

developed by the Soil Conservation Service, was used to route the flood

through the channel, and the Modified PuIs Method of Reservoir Routing was

3. PEAK REDUCED BECAUSE OF DETENTION STORAGE 8EHIND THE AT&SF RAILROAD TRACKS.

used to route the storm through any significant detention storage areas

(pre-planned or inadvertant). The runoff volumes and peak flow rates for

the 5, 10 and 10o-year storms are summarized in Table II.

TABLE ][.

MAJOR DRAlNAGEWAY PLANNING
LEE GULCH - LITTLE CREEK
URBAN DRAINAGE AND FLOOO CONTROL DISTRICT
CITY OF LITTLETON ARAPAHOE COUNTY

PEAK RUNOFF AND STORM VOLUME

I<.K-&N-A Inc., Consultin9 E"9ineers
7456 W. 5th Ave. Denver, Colorada

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