FLOOD04017

• County: Jefferson
• County: Denver
• Community: Columbine Valley, Denver
• Stream Name: Dutch Creek, Lilley Gulch, Coon Creek,
• Basin: South Platte
• Title: Flood Hazard Area Delineation
• Date: 5/1/1978
• Prepared For: Jefferson County / Arapahoe County
• Prepared By: UDFCD
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

The Nevada Irrigation Ditch located east of Platte Canyon Road through Colum-

bine Valley presents another pttential problem in that it currently intercepts

flood flows from the study basin as well as other tributary areas. The ditch

will store and convey flood waters until the point when the banks begin to

overtop. It is not possible, within the scope of this project, to determine

where ditch overtopping will occur. Flood water accumulation could occur be-

low the irrigation ditch, particularly near del ineated flood plains. Another

ditch related concern voiced by the residents of the area not specifically

addressed in this project is the possibility that the ditch and other similar

type irrigation facilities would be abandoned and, through maintenance neglect

or future changes in land use development, render the ditch useless to inter-

cept any storm water runoff.

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located on the major drainageways and offered considerable opportunity

to control the flows downstream on Dutch Creek and Lilley Gulch.

Drainageway Location
Dutch Creek - Arapahoe Co.

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The flows used for the water surface computations were obtained from

the unit hydrographs and discharge probability curves developed in the

hydrologic investigation. The flood routing program was applied to

Beers Sisters, Grant A, and Johnson's Lakes from which water surface

elevations for the various design flood frequencies were developed.

The computed water surface elevations for the 10- and 100-year design

floods were plotted on the 1" = 100' scale mapping from which flood plains

for the 100-year design flood was drawn. For areas where supercritical

flow occurred in the drainagway, critical depth was computed and plotted

in determining flood depths.

Lilley Gulch - Jefferson Co.

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Duthh Creek - Town of
Columbine

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Analysis

Coon Creek - Jefferson Co.

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Flood profiles were run on each of the drainageways within the Basin.

The 2-, 5-, 10-, 50-, and 100-year flood profiles were calculated for the

totally developed basin utilizing peak flows developed in the hydro-

logic investigation. The limits of the computed flood plain for the

100-year event is presented on the drawings contained in this report.

From the 1" = 100' plotted flood plain information, an analysis of po-

tential flood plain damages was made.

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Both the Basin hydrologic investigation and the flood plain del ineation

analysis identified numerous potential problem areas for damage to

existing development. The location by drainage reach, defined as the

length of drainageway between deSign points, of some of the major po-

tential problem areas are listed as follows:

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Drainageway Location
Dutch Creek - Jefferson Co.

Potential Flood Damage Problem Area

Flood water flowing over major arterial
streets of Kipling Street, Coal Mine
Road and Pierce Street, varying in depth
from 0.5' to 4' causing possible traffic
accidents and disruption.

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Floodwater accumulation from drainageway
overflow along Weaver Drive affecting
several single family residences.

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Potential Flood Damage Problem Area

Flood water accumulation and drainageway
overflow affecting several homes on Dutch
Creek Road and a ranch and homesite off of
Platte Canyon Road.

Flood water flowing over Platte Canyon
Road approximately 2' deep causing possible
traffic accid ts and disruption.

Flood water accumulation and drainageway
overflow affecting the golf course club
house/restaurant facility and a number of
single family residences.

Flood water accumulation and drainageway
overflow (diverted flow at Pierce) affect-
ing tennis courts, shower and pool facil ity
west of Kipl ing Street to a depth of over
I foot.

Flood water flowing over major arterials
of Simms, Kipl ing and Bowles Avenue in
depth varying from 1 to 1.5' causing
possible traffic accidents and disruption.
Also affecting several homes at Bowles
Avenue/Leawood Drive intersection adjacent
to the major drainageways.

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