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Table of Contents - Special Paper 381

Hydraulic tests of Miocene volcanic rocks at Yucca Mountain and Pahute Mesa and implications for groundwater flow in the Southwest Nevada Volcanic Field, Nevada and California

by Arthur L. Geldon

Introduction 1

Location of Study Area		 2
Regional Geology 2

Regional Groundwater Hydrology		 4
    Hydrostratigraphic Units 7
    Groundwater in the Younger Tertiary Tuff and Lava Flows Hydrostratigraphic Unit 13

Hydraulic Tests		 24
    Well Completion and Instrumentation 24
    Flow Distribution in Boreholes 28
    Earth Tides and Barometric Effects 30
    Analytical Methods 33
    Constant-Rate Pumping, Injection, and Airlift Tests 33
    Slug-Injection and Swabbing Recovery Tests 35
    Analytical Uncertainty 36
    Effects of Test Scale on Determination of Hydraulic Properties 36

Hydraulic Properties		 38
    The C-holes Complex 39
    Pumping Test in UE-25 c#3, May 22 to June 1, 1995 44
    Miscellaneous Hydraulic Tests at the C-holes Complex, 1984–1998 49
    Pumping Test in UE-25 c#3, May 8, 1996, to November 12, 1997 52
    Drill Hole Wash 57
    Frenchman Flat 59
    Well Cluster ER-20-6, Western Pahute Mesa 60
    Knickerbocker Site, Western Pahute Mesa 63

Distribution of Hydraulic Conductivity		 64
    Relation of Lithology to Hydraulic Conductivity 67
    Hydraulic Conductivity Distribution at Yucca Mountain 67
    Hydraulic Conductivity Distribution at Pahute Mesa 67

Summary and Conclusions		 67
Appendix A 73
Appendix B 74
References Cited 90