FLOOD06025

• County: Boulder
• Community: Louisville
• Stream Name: Coal Creek, Rock Creek
• Basin: South Platte
• Title: Major Drainageway Planning
• Date: 11/1/1982
• Prepared For: Boulder County
• Prepared By: WRC Engineering, Inc.
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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I, INTRODUCTION

presented to the City Council on March 23, 1982. The final alignment for the

Outfall System was selected and ,WRC was authorized to proceed with preparation

of the plan on April 2, 1982. This report presents the preliminary design of

the reconunended Out fall System for the Louisville/Boulder County area.

A. Authorization

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This study for the Planning of Louisville/Boulder County Area Outfall

System was authorized under the terms of the contract between the Urban Drainage

and Flood Control District (UD&FCD), City of Louisville, Boulder County, and

Water Resources Consultants, Inc. (WRC), dated July 10, 198 I (Agreement No, 80-

12.3). The Notice to Proceed for the project was dated July 23, 1981, at which

time the pencil manuscripts for the mapping were submitted to WRC. The mapping

of the basin was accomplished under separate contract between the UD&FCD and

Landmark Mapping, Ltd.

C. Mapping and Surveys

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B, Purpose and Scope

The topographic maps were prepared by Landtnark Mapping, Ltd. under separate

contract with the UD&FCD, The plan maps were compiled and prepared at a scale of

I" = 200' with 4-foot contour interval, The topography was compiled by photo-

grammetry from photographs taken on April 23, 1982. The ground surface elevations

along the selected outfall alignment were obtained by Landmark Mapping, Ltd, uSlng

standard aerial mapping techniques and are accurate to within I-foot. These data

were plotted on the profile sheets contained herein and used for preliminary design

purposes,

The study was performed in two phases, the Criteria Development phase and
the Outfall System Planning phase.

D. Acknowledgement

The purpose of the Criteria Development was to establish a basinwide drainage

design and technical criteria to be used for all drainage analysis of subdivision

plats, planned unit developments, or other proposed construction within the Louis-

ville/Boulder County area. The criteria was also utilized in the development and

evaluation of alternate outfall systems (second phase of the work), The criteria

was published in April, 1982 (Reference-I) and accepted by the City for administra-

tion. Included in the document are drainage policies, subdivision planning require-

ments, as well as hydrologic and hydraulic evaluation and design criteria.

This report was prepared by Water Resources Consultants, Inc. under the

guidance of and the coordination with an advisory committee comprised of:

* Mr, David I, Blanchard / City of Louisville - City Engineer

* Mr, Ken Huson / City of Louisville - Staff Engineer

* Mr. Mike G, Serlet / Boulder County - Drainage Engineer

~ Mr. Ben Urbonas / Urban Drainage and Flood Control District - Project

Director

The purpose of the Outfall System Planning phase was to develop and evaluate

alternate alignments and drainage designs for the Outfall Systenl, For the purposes

of this analysis, an Outfall System is a drainage system designed to serve 130 acres

or more of tributary urban area. Several alternatives were developed and evaluated

for the 20.3 miles of drainageways. The alternatives and recommendations were

The following individuals on the staff of Water Resources Consultants, Inc.

have contributed to the preparation and completion of this report:

* Mr. A. S. Andrews, P,E, - Project Director

* Mr. William P. Ruzzo, P.E. - Project Manager

~ Mr. Alan J. Leak - Water Resources Engineer

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