FLOOD00189

• County: Denver
• Community: Denver, Lakewood
• Stream Name: Weir Gulch Tributaries
• Title: Major Drainageway Planning
• Date: 7/1/1978
• Prepared For: Denver County
• Prepared By: UDFCD
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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CHAPTER 1
INTRODUCTION

must be in sufficient detail to enable communities to plan ahead with
the allocation of funds for the improvements.

C. METHOD OF ANALYSIS
The methods and procedures used in the analysis are based on the
criteria set forth in the consultant agreement, the "Urban Storm Drainage
Criteria Manual", applicable current codes, available computer programs, and
other accepted analytical procedures. Subsequent to data gathering and
field reconnaissance, work commenced to establish basin and sub-basin
boundaries.
For each sub-basin, the area, length, length to centroid, slope, and
imperviousness was defined for existing and future conditions. Design storms
were obtained by using data provided in Project Reuse (7), which lists the
design storms for each township in the Denver metropolitan area. The two
major basins considered are located in T4S, R68W, and R69W. Since the
greater portion of both basins is located in T4S, R69W, the precipitation
data for that Township was used. The unit hydrographs and the storm
hydrographs were determined by using a computer program developed by
Leonard Rice Consulting Water Engineers, and a computer program developed
by the Urban Drainage and Flood Control District. The hydrographs of the
sub-basins were combined by calculating the travel time of one-half of
the peak flow between two design points and defining it as the lag time.
A preliminary design was prepared based on the recommendations made in
the Phase A Report and the comments received from the Urban Drainage and
Flood Control District, the City and County of Denver, and the City of Lakewood.
The preliminary design is in sufficient detail to allow the estimate of
construction costs for improvements, land acquisition costs and costs for
operation and maintenance.

A. AUTHORIZATION
This study covering the 1st Avenue and Dakota Avenue Tributaries
of Weir Gulch and the Depew Street Sub-basin of the 1st Avenue Tributary
was authorized by the Urban Drainage and Flood Control District in joint
sponsorship with the City and County of Denver and the City of Lakewood.
The terms of the contract between the sponsors and Centennial Engineering,
Inc., dated October 5, 1976, allowed initiation of the work on the Phase A
Report on January 3, 1977. The printed Phase A Report was submitted on
October 17, 1977. Addendum 1 to the Phase A Report was authorized on
January 4, 1978, with immediate initiation of the work. The printed
Addendum 1 to the Phase A Report was submitted on March 17, 1978.
Authorization to proceed with Phase B was given by letter dated
March 3, 1978. The authorization included the Depew Street Sub-basin.

B. PURPOSE AND SCOPE
The purpose of this study is to develop major drainageway planning foy'
two tributaries of Weir Gulch, the 1st Avenue Tributary, the Dakota Avenue
Tributary and the Depew Street Sub-basin of the 1st Avenue Tributary. During
Phase A of this study the primary emphasis was on hydrological and
hydraulic analysis of existing drainage facilities and the development and
comparison of improvement alternates. The comparison was based on
benefit/cost analysis, the environmental impact, and engineering feasibility.
During Phase B of this study the primary emphasis is on review of the Phase A
recommendation, preliminary design of the recommended improvements, and the
preparation of a cost estimate. The preliminary design and the cost estimate

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