FLOOD04421

• County: Arapahoe
• County: Douglas
• Community: Arapahoe, Douglas
• Stream Name: Piney Creek, Cottonwood Creek, Lone Tree,
• Basin: South Platte
• Title: Flood Hazard Area Delineation
• Date: 10/1/1975
• Prepared For: UDFCD
• Prepared By: Arapahoe, Douglas
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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- HISTORICAL FLOODS -

the high plains approximately 20 miles east of the foothills.

Information on historical floods on Piney Creek, Cottonwood Creek,

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The basins are presently undeveloped except for localized im-

Lone Tree Creek and Murphy Creek was obtained through conversa-

provements. The streams are natural in location and size. The

tions with local residents, research of the historic files of

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flood plains are not heavily covered with vegetation but remain

the Denver Post, The Rocky Mountain News, the Denver Public

Library and various D.S.G.S. publications. No stream gauging

open and clear and highly erodible. The channel bottom in lower

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reaches of Piney Creek is sandy and very unstable.

stations exist on any of the streams and thus a record of peak

discharges which have occurred within the drainage areas is un-

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Future basin development in the study areas was considered by

available. Little detailed information on past flood events for

utilizing comprehensive land use plans prepared by Arapahoe and

these undeveloped tributary streams is available.

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Douglas Counties. Lone Tree Creek and portions of the Cotton-

Floods on the South Platte River have occurred throughout the

wood Creek, Piney Creek and Murphy Creek basins bisect the

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history of Arapahoe County. The earliest recorded flood was in

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preliminary alignment of the 1-470 corridor in Arapahoe County.

The metropolitan side of the corridor is planned for low density

1844. Floods have also been recorded on Cherry Creek, going

back before 1858, by Indian accounts. The recorded peak flood

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residential and light industrial development. Douglas County

plans for low density rural development in the upper reaches of

the Piney Creek basin. In the Cottonwood Creek basin, along 1-25,

discharges for the major floods and the year of flooding are

tabulated in Table 2 for these two streams.

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light industrial development is planned.

Table 2
Historical Flood Discharges

Year

Discharge (cfs)

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Specific drainage basin information for each of the streams is

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Stream

Total
Drainage Area
(Sq. Mi.)

Stud1' Length
Mi.}

Ave.
Slo,e
(ft. m].,)

South Platte River
1912
1921
1933
1935
1942
1965
1973

at Denver

tabulated in Table 1.

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Table 1
Drainage Basin Data

13,000
8,790
22,000
12,320
10,200
40,300
17,600

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Piney Creek 21.9
Murphy Creek 12.2
Cottonwood Creek 8.7
Lone Tree Creek 1.7

11. 9
10.2
7.6
3.6

66
64
95
81

Cherry Creek near
1933
1945
1946
1963
1965

Melvin (Arapahoe Rd.)
34,000
10,700
17,600
10,800
39,900

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