PROJ00173

• Contract/PO #: C153369
• Contractor Name: St. Vrain and Left Hand Water Conservancy District
• Water District: 0
• County: Boulder
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

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II SECTION 1.
SECTION 2.
II 2.1
2.2
2.3
I 2.4
:1 2.5
2.6
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II SECTION 3.
SECTION 4.
'II 4.1
4.2
4.3
,il 4.4
4.5
1 4.6
II 4.7
SECTION 5.
5.1
::1 5.2
5.2.1
5.2.2
, 5.2.3
il 5.3
5.3.1
5.3.2
[I 5.4
5.5
5.5.1
II 5.5.2
5.5.3
5.5.4
il 5.6
5.6.1
5.6.2
5.5.3
;1 SECTION 6.
~I 6.1
6.2
6.3
6.4
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TABLE OF CONTENTS

INTRODUCTION .............................................. 1- 1

GENERAL INFORMATION ....................................... 2- 1
Location, Size, and General Setting ....................... 2- 1
Topography and Drainage ................................... 2- 1
So; 1 and Rock Outcrops .................................... 2- 3
Vegetation ................................................ 2- 3
C1 imate ................................................... 2- 4
Ex i s t i n9 Land Use ......................................... 2 - 4

PROJECT DESCRIPTION ....................................... 3- 1

INVESTIGATIVE PROCEDURE ................................... 4- 1
Review of Geological Literat~re ........................... 4- 1

Topographic Mapping ....................................... 4- 1
Geologic Mapping ........................................... 4- 1
Geopnysical Inves~igations ................................ 4- 2
Drilling and Down-the-Hole Testing ........................ 4- Z

Joint Surveys.............................................. 4- 4
Geologil.: Cross Sections ................................... 4- 4

GEOLaGY ................................................... 5- 1
Geomorpho logy ................................................ 5- 1
Soil and Rock Materials .................................... 5- 1
General Statements ....................................... 5- 1
Surficial Deposits of Quaternary Age ................... 5- 2

Bedrock Un; ts ............................................. 5- 2
Geologic Structure .......................................... 5- 2
Regional Structure ...................................... 5- 2
Site-Specific Structure ................................ 5- 3

Ground Water .............................................. 5- 6
Mineral Resources ......................................... 5- 7
C~nstruction Materials ................................. 5- 7

Building Stone .... ............. ... ... ..... ... .......... 5-10
Metallic Minerals................ ............ .......... 5-10
Other Minerals.......................................... 5-11
Seismicity................................................ 5-11
General Statments and Definitions ...................... 5-11
Seisomological Setting in Western United States ........ 5-14
Seisomclogical Setting in Colorado and at
the Coffintop Site ..................................... 5-15

CONCLUSIONS AND RECOMMENDATIONS ........................... 6- 1
Fundamental Conclusion .................................... 6- 1
Dam Foundation ............................................ 6- 1
Dam Abut'Tlents .............................................. 6- 2
Seismicity and the Design Earthquake ...................... 6- 3

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