FLOOD10485

• County: Arapahoe
• County: Douglas
• Stream Name: Big Dry Creek
• Basin: South Platte
• Title: Big Dry Creek ‎(Arapco)‎ & Tributaries - Major Drainageway Planning - Phase B Preliminary Design Report
• Date: 4/1/1998
• Prepared For: Arapahoe County, Douglas County, Englewood, Greenwood Village, Littleton, UDFCD
• Prepared By: WRC Engineering, Inc.
• Floodplain - Doc Type: Flood Mitigation/Flood Warning/Watershed Restoration

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South Suburban Parks and Recreation District
. Non-motorized Transportation and Greenway Plan

identify

to

and

values

to determine channel roughness

performed

investigation was

field

A

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The information gathered included channel geometry and

potentially sensitive environmental areas.

Colorado Department of Transportation
. Construction Plans for Atchinson, Topeka and Sante Fe Bridge Crossing

and photographs of the facilities and channel

drainage structures

roughness,

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INFORMATION PROCUREMENT

D,

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Water Board
Water Main Maps along Big Dry Creek alignment

Denver
.

where available, were provided

Maps of existing drainage facilities and previous drainage studies,

the process of this study,

During

study participants.

by
several agencies, organizations and individuals

the

(WRC)

Inc.

WRC Engineering,

to

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Centennial Water and Sanitation District
. Utility Maps

staff to obtain data and

were contacted by WRC

ist of contributors and

IS a

regarding storm drainage within the study area. The following

history

I,

South Englewood Sanitation District
. Utility Maps

the pertinent data obtained

Urban Drainage and Flood Control District

Lehow A venue Bridge Information
Aerial Photos

.
.

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South Arapahoe Sanitation District (Meurer & Associates)
. Utility Maps

ANALYSIS AND DESIGN CRITERIA

E.

Douglas County
. Land Ownership Maps
. Detention Pond Grading Plans
. Pertinent Drainage Studies
. Land Use Maps
. Flood Insurance Study

II

:1

I,

The Major Drainageway Plannmg and Flood Hazard Area Delineation was performed per the terms

of the contract and the guidelines and criteria set forth in the Urban Storm Drainage Criteria Manual

Also utilized were the storm drainage design and technical criteria of the

).

various project sponsors.

(USDCM) (Reference

Arapahoe County
. Comprehensive Plan
. Hydrology Information on Fillmore Tributary
. Assessor's Maps with
. Orchard Road Bridge

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Drainage Facilities
Information

I'

to establish watershed

reconnaissance work

initial data gathering and field

the

Subsequent to

City of Littleton
. Construction Plans for Littleton Boulevard Bridge

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the study area was divided into separate sub-

drainage features,
watershed

storm

boundaries and existing

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slope, and

length,

(i.e.. area,

The physical parameters

the major

within

watersheds

Pertinent Drainage Studies
Flood Insurance Study
City and Zoning Maps

.

.
.

mperviousness) of each sub-watershed were then defined and the design storm hydrographs

percent
developed for the various recurrence

:1

the Colorado Urban Hydrograph Procedure

the UD&FCD and the

intervals using
information was obtained from

The design rainfal

(CUHP, Reference 3)

City of Englewood
. Trail Plans

I

4)

depths (Reference

rainfall

hour NOAA

City of Greenwood Village
. Horseman's Park Construction Plans

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1-3

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