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

I

Gather and assemble information available regarding drainage facilities, either planned or

A Report.

since preparation of the Phase

constructed

1

I

INTRODUCTION

I.

I

Update the hydrologic and hydraulic aspects of the drainage area to reflect the drainage

improvements selected by the project sponsors.

2.

GENERAL

A.

I

Solicit public mput regarding the drainage improvements selected by the project sponsors

3

Urban Drainage and Flood Control District

the

study authorized by

of a

part

s

This report

I

for preliminary design

Drainageway Planning and Flood Hazard Area

the agreement regarding Major

(UD&FCD) in

995

0,

dated Apri

(ARAPCO) and Tributaries,

Big Dry Creek

for

(FHAD)

Delineation

I

improvements including plans,

Prepare a preliminary design of the selected drainage

4

consists of the entire Big Dry Creek

1-

in Figure

The study area, shown

No. 9501.08)

(Agreement

mprovements.

of said

s

profiles, and detai

the City of Englewood, the City of

City of Littleton

watershed which encompasses parts of the

Greenwood Village, Arapahoe County and Douglas County.

I

Prepare a detailed cost estimate for the selected drainage improvements with costs separated

5.

by jurisdiction and adjusted into drainageway improvement costs including contingencies,

part (Phase A) covers the hydrological. hydraulic,

The first

s divided into three parts.

The study

,I

legal and

services,

engineering and construction

relocation costs,

utility

traffic costs,

1996

report was finalized on July 12,

The Phase A

and alternative evaluation aspects of the study.

annual

of

value

present

and

costs,

acquisition

property

costs,

inistrative

adm

the

prepared, covers

was

this report

which

for

(Phase B)

second part

The

(Refererrce 22)

I

operation/maintenance costs.

s the FHAD, which was finalized on

The third part

preliminary design ofthe selected alternative

Provide a discussion on prioritization of the selected drainage improvements.

6

summarized herem, was submitted for

6),

9, 1996. The Hydrology Report (Reference

November

I

1996

12,

1995 and was finalized on July

0,

review on November

I

B Report a summary of the study's analysis, discussions, results

Present in a written Phase -

7.

PURPOSE AND SCOPI:

B.

the improvements selected to address the drainage problems identified in the Phase

and

,I

A Report.

to update the original master plan report for Big Dry Creek, Major

IS

The purpose of this study

0)

975 (Reference

Drainageway Master Plan Big Dry Creek, dated June

I

MAPPING AND SURVEYS

C.

975 including

sInce

This update has been necessitated by several factors which have changed

I

were prepared by Landmark Mapping under separate contract
00'

The topographic maps for this project

development conditions, channel conditions and improvements,

and use assumptions,

111

changes

with 2-foot

=

"

a scale of

were compiled and prepared at

with UD&FCD. The plan maps

s believed that these changes are

and the general public's perceptions, desires and requirements. It

,I

2.0

n electronic format as an AutoCAD Version

were submitted

The maps

ntervals

contour

not in the best interests

s

of such significance that continued future reliance on the 1975 master plan

994

topography was compiled from aerial photographs taken on December 2

The

drawing.

of the project sponsors nor the affected citizens and businesses

I,

of existing

sizes and configurations

the

showing

Culvert and bridge diagrams were provided

Base mapping for the hydrologic maps consist ofU.S.G.S. quadrangle maps

drainage structures.

is as follows

B part of the study

Drainageway Planning Phase

The general scope of the Major

I

-1

of Agriculture Soil

types and hydrologic soil groups.

Department

the U.S

prepared by

Conservation Service were used to determine soil

surveys

Soil

000'

"

at a scale of

I

I