U.S. Department of the Interior 

U.S. Geological Survey

Hydrologic Properties and Ground-Water Flow Systems 

of the Paleozoic Rocks in the Upper Colorado River Basin 

in Arizona, Colorado, New Mexico, Utah, and Wyoming, 

Excluding the San Juan Basin

Regional Aquifer-System Analysis

Professional Paper 1411-B

UTAH

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USGS
Hydrologic Properties and Ground-Water 

Flow Systems of the Paleozoic Rocks 

in the Upper Colorado River Basin in 

Arizona, Colorado, New Mexico, Utah, and 

Wyoming, Excluding the San Juan Basin

By ARTHUR L. GELDON

REGIONAL AQUIFER-SYSTEM ANALYSISUPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1411-B
U.S. DEPARTMENT OF THE INTERIOR 

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY 

Charles G. Groat, Director

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.

Reston, Virginia 2003

Library of Congress Cataloging-in-Publication Data

Geldon, Arthur L.

Hydrologic properties and ground-water flow systems of the paleozoic rocks in the Upper Colorado River Basin in Arizona, Colorado, 

New Mexico, Utah, and Wyoming, excluding the San Juan Basin / by Arthur Geldon.

p. cm. (U.S. Geological Survey professional paper ; 1411-B) (Regional aquifer-system analysis)

Includes bibliographical references.

ISBN 0-607-98594-1

1. Groundwater Colorado River Watershed (Colo.-Mexico) 2. Geology,

Stratigraphic Paleozoic. I. Title. II. Series. III. Series: Regional aquifer-system analysis 

GB1022 .G45 2002 

551.49'09791'3--dc21 2002023651

For sale by U.S. Geological Survey, Information Services 

Box 25286, Denver Federal Center 

Denver, CO 80225
FOREWORD

THE REGIONAL AQUIFER-SYSTEM ANALYSIS PROGRAM

The Regional Aquifer-System Analysis (RASA) program was started in 1978 after a congressional mandate to develop quantitative appraisals of the major ground-water systems of the United 

States. The RASA program represents a systematic effort to study a number of the Nation's most 

important aquifer systems which, in aggregate, underlie much of the country and which represent 

important components of the Nation's total water supply. In general, the boundaries of these studies 

are identified by the hydrologic extent of each system and accordingly transcend the political subdivisions to which investigations have often arbitrarily been limited in the past. The broad objective 

for each study is to assemble geologic, hydrologic, and geochemical information, to analyze and 

develop an understanding of the system, and to develop predictive capabilities that will contribute to 

the effective management of the system. The use of computer simulation is an important element of 

the RASA studies, both to develop an understanding of the natural, undisturbed hydrologic system, 

and of any changes brought about by human activities, as well as to provide a means of predicting 

the regional effects of future pumping or other stresses.

The final interpretive results of the RASA program are presented in a series of U.S. Geological 

Survey Professional Papers that describe the geology, hydrology, and geochemistry of each regional 

aquifer system. Each study within the RASA program is assigned a single Professional Paper number, and where the volume of interpretive material warrants, separate topical chapters that consider 

the principal elements of the investigation may be published. The series of RASA interpretive 

reports begins with Professional Paper 1400, and thereafter will continue in numerical sequence as 

the interpretive products of subsequent studies become available.

Charles G. Groat 

Director
FOREWORD

THE REGIONAL AQUIFER-SYSTEM ANALYSIS PROGRAM

The Regional Aquifer-System Analysis (RASA) program was started in 1978 after a congressional mandate to develop quantitative appraisals of the major ground-water systems of the United 

States. The RASA program represents a systematic effort to study a number of the Nation's most 

important aquifer systems which, in aggregate, underlie much of the country and which represent 

important components of the Nation's total water supply. In general, the boundaries of these studies 

are identified by the hydrologic extent of each system and accordingly transcend the political subdivisions to which investigations have often arbitrarily been limited in the past. The broad objective 

for each study is to assemble geologic, hydrologic, and geochemical information, to analyze and 

develop an understanding of the system, and to develop predictive capabilities that will contribute to 

the effective management of the system. The use of computer simulation is an important element of 

the RASA studies, both to develop an understanding of the natural, undisturbed hydrologic system, 

and of any changes brought about by human activities, as well as to provide a means of predicting 

the regional effects of future pumping or other stresses.

The final interpretive results of the RASA program are presented in a series of U.S. Geological 

Survey Professional Papers that describe the geology, hydrology, and geochemistry of each regional 

aquifer system. Each study within the RASA program is assigned a single Professional Paper number, and where the volume of interpretive material warrants, separate topical chapters that consider 

the principal elements of the investigation may be published. The series of RASA interpretive 

reports begins with Professional Paper 1400, and thereafter will continue in numerical sequence as 

the interpretive products of subsequent studies become available.

Charles G. Groat 

Director
CONTENTS

	Page

Foreword........................................................................................................................................................... Ill

Abstract............................................................................................................................................................. Bl

Introduction....................................................................................................................................................... 2

Location of Study..................................................................................................................................... 2

Previous Investigations............................................................................................................................. 4

System of Numbering Wells and Springs................................................................................................ 4

Acknowledgments..................................................................................................................................... 6

Methods of Analysis ......................................................................................................................................... 6

Porosity..................................................................................................................................................... 6

Permeability.............................................................................................................................................. 6

Hydraulic Conductivity............................................................................................................................ 11

Transmissivity........................................................................................................................................... 14

Storativity.................................................................................................................................................. 17

Yield.......................................................................................................................................................... 18

Physical Setting................................................................................................................................................. 18

Topography............................................................................................................................................... 18

Middle Rocky Mountains................................................................................................................. 18

Wyoming Basin................................................................................................................................ 19

Southern Rocky Mountains.............................................................................................................. 20

Colorado Plateaus............................................................................................................................. 22

Climate...................................................................................................................................................... 22

Drainage.................................................................................................................................................... 25

Regional Geology.............................................................................................................................................. 29

General Hydrologic Properties of the Paleozoic Rocks.................................................................................... 34

Hydrologic Properties of the Four Corners Aquifer System............................................................................. 41

Flathead Aquifer....................................................................................................................................... 43

Thickness and Lithology.................................................................................................................. 43

Porosity and Permeability................................................................................................................ 46

Hydraulic Conductivity and Transmissivity .................................................................................... 46

Yields From Wells and Springs ....................................................................................................... 48

Gros Ventre Confining Unit..................................................................................................................... 48

Thickness and Lithology.................................................................................................................. 48

Permeability and Hydraulic Conductivity ....................................................................................... 48

Yields from Wells and Springs........................................................................................................ 48

Bighorn Aquifer........................................................................................................................................ 50

Thickness and Lithology.................................................................................................................. 50

Porosity and Permeability................................................................................................................ 50

Hydraulic Conductivity and Transmissivity.................................................................................... 50

Yields from Wells and Springs........................................................................................................ 52

Elbert-Parting Confining Unit.................................................................................................................. 52

Thickness and Lithology.................................................................................................................. 52

Porosity and Permeability................................................................................................................ 53

Hydraulic Conductivity and Transmissivity .................................................................................... 55

Yields from Wells and Springs........................................................................................................ 55

Redwall-Leadville Zone of the Madison Aquifer.................................................................................... 56
VI CONTENTS

	Page

Thickness and Lithology.................................................................................................................. B58

Porosity and Permeability................................................................................................................ 58

Hydraulic Conductivity, Transmissivity, and Storativity................................................................. 59

Yields from Wells and Springs........................................................................................................ 67

Darwin-Humbug Zone of the Madison Aquifer...................................................................................... 70

Thickness and Lithology.................................................................................................................. 72

Porosity, Permeability, and Hydraulic Conductivity ....................................................................... 72

Transmissivity .................................................................................................................................. 72

Yields from Wells and Springs........................................................................................................ 72

Hydrologic Properties of the Four Corners Confining Unit.............................................................................. 72

Belden-Molas Subunit.............................................................................................................................. 74

Thickness and Lithology.................................................................................................................. 74

Porosity and Permeability................................................................................................................ 74

Hydraulic Conductivity and Transmissivity.................................................................................... 78

Yields from Wells and Springs........................................................................................................ 79

Paradox-Eagle Valley Subunit................................................................................................................. 79

Thickness and Lithology.................................................................................................................. 80

Porosity and Permeability................................................................................................................ 80

Hydraulic Conductivity and Transmissivity .................................................................................... 85

Yields from Wells and Springs........................................................................................................ 86

Hydrologic Properties of the Canyonlands Aquifer.......................................................................................... 87

Cutler-Maroon Zone................................................................................................................................. 88

Thickness and Lithology.................................................................................................................. 90

Porosity and Permeability................................................................................................................ 90

Hydraulic Conductivity and Transmissivity .................................................................................... 95

Yields from Wells and Springs........................................................................................................ 96

Weber-DeChelly Zone............................................................................................................................. 99

Thickness and Lithology.................................................................................................................. 99

Porosity and Permeability................................................................................................................ 99

Hydraulic Conductivity, Transmissivity, and Storativity................................................................. 104

Yields from Wells and Springs........................................................................................................ 105

Park City-State Bridge Zone.................................................................................................................... 107

Thickness and Lithology.................................................................................................................. 109

Porosity and Permeability................................................................................................................ 109

Hydraulic Conductivity and Transmissivity .................................................................................... 115

Yields from Wells and Springs ........................................................................................................ 115

Ground-Water Movement................................................................................................................................. 117

Recharge to the Paleozoic Rocks............................................................................................................. 120

Precipitation...................................................................................................................................... 121

Interbasin Flow................................................................................................................................. 126

Streamflow ....................................................................................................................................... 126

Flow Paths................................................................................................................................................ 126

Circulation in the Four Comers Aquifer System ............................................................................ 126

Effect of the Four Corners Confining Unit on Circulation............................................................. 133

Circulation in the Canyonlands Aquifer.......................................................................................... 134

Rates of Ground-Water Movement.......................................................................................................... 137

Discharge from the Paleozoic Rocks ....................................................................................................... 138

Seepage to Streams and Springs...................................................................................................... 138

Withdrawal from Wells.................................................................................................................... 140

Evapotranspiration............................................................................................................................ 143

Leakage to Mesozoic and Tertiary Rocks ....................................................................................... 143

Interbasin Flow................................................................................................................................. 143

Ground-Water Budget for the Upper Colorado River Basin................................................................... 144

Summary and Conclusions................................................................................................................................ 144

Selected References.......................................................................................................................................... 147
CONTENTS VII

PLATES

(Plates are in pocket)

PLATE 1. Map showng geographic features of the Upper Colorado River Basin and vicinity in Arizona, Colorado, New Mexico, Utah, and Wyoming.

2. Map showing unit-averaged porosity and hydraulic conductivity of the Redwall-Leadville zone of the Madison aquifer in the Upper Colorado River 

Basin and vicinity in Arizona, Colorado, New Mexico, Utah, and Wyoming.

3. Map showing composite transmissivity of and maximum yields from the Redwall-Leadville zone of the Madison aquifer in the Upper Colorado 

River Basin and vicinity in Arizona, Colorado, New Mexico, Utah, and Wyoming.

4. Map showing unit-averaged hydraulic conductivity and composite transmissivity of the Paradox-Eagle Valley subunit of the Four Corners confining 

unit in the Upper Colorado River Basin and vicinity in Arizona, Colorado, New Mexico, Utah, and Wyoming.

5. Map showing unit-averaged porosity and hydraulic conductivity of the Cutler-Maroon zone of the Canyonlands aquifer in the Upper Colorado River 

Basin and vicinity in Arizona, Colorado, New Mexico, Utah, and Wyoming.

6. Map showing composite transmissivity of and maximum yields from the Cutler-Maroon zone of the Canyonlands aquifer in the Upper Colorado 

River Basin and vicinity in Arizona, Colorado, New Mexico. Utah, and Wyoming.

7. Map showing unit-averaged porosity and hydraulic conductivity of the Weber-De Chelly zone of the Canyonlands aquifer in the Upper Colorado 

River Basin and vicinity in Arizona. Colorado, New Mexico, Utah, and Wyoming.

8. Map showing composite transmissivity of and maximum yields from the Weber-De Chelly zone of the Canyonlands aquifer in the Upper Colorado 

River Basin and vicinity in Arizona, Colorado, New Mexico, Utah, and Wyoming.

9. Map showing unit-averaged porosity and hydraulic conductivity of the Park City-State Bridge zone of the Canyonlands aquifer in the Upper 

Colorado River Basin and vicinity in Arizona, Colorado. Utah, and Wyoming.

10. Map showing composite transmissivity of and maximum yields from the Park City-State Bridge zone of the Canyonlands aquifer in the Upper 

Colorado River Basin and vicinity in Arizona, Colorado, Utah, and Wyoming.

11. Map showing potentiometric surfaces of the Madison and Canyonlands aquifers in the Upper Colorado River Basin and vicinity in Arizona. 

Colorado, New Mexico, Utah, and Wyoming.

12. Map showing difference between potentiometric heads in the Canyonlands aquifer and Madison aquifer in the Upper Colorado River Basin and 

vicinity in Arizona, Colorado, New Mexico, Utah, and Wyoming.

13. Map showing average linear velocity of water in the Redwall-Leadville zone of the Madison aquifer and Weber-De Chelly zone of the Canyonlands 

aquifer in the Upper Colorado River Basin in Arizona, Colorado, New Mexico, Utah, and Wyoming.

ILLUSTRATIONS

FIGURE 1. Map showing areas covered by ground-water reports in the Upper Colorado River Basin................................................................................ B5

2. Map showing generalized distribution of thermal gradients in deep boreholes in the Upper Colorado River Basin......................................... 10

3. Graph showing relations for sandstone and carbonate rocks between permeability determined from cores and permeability

determined from drill-stem tests at closely spaced sites \n the Upper Colorado River Basin ............................................................................ 13

4. Photograph showing Uncompahgre River at Ouray, Colorado, near site of well OX-3 (NMB44-07-31cbd3)................................................ 15

5. Graph showing drawdown in well OX-3 (NMB44-07-31cbd3 ) at Ouray. Colorado, during aquifer test of April 25, 1988............................ 16

6-9. Photographs showing:

6. Landscapes of the Middle Rocky Mountains physiographic province: A, Wind River Mountains; B, Western Uinta

Mountains............................................................................................................................._^ 19

7. Landscapes of the Wyoming Basin physiographic province: A, Green River Basin; B. Rock Springs Uplift......................................... 20

8. Landscapes of the Southern Rocky Mountains physiographic province: A. Elk Mountains; B, Sawatch Range..................................... 21

9. Landscapes of the Colorado Plateaus physiographic province: A, Monument Upwarp; B, Paradox Basin.............................................. 23

10. Graph showing average annual precipitation in the Upper Colorado River Basin and location of sites used in analyses

of climatic data.................................................................................................................................................................................................... 24

11. Graphs showing relations of precipitation and temperature to altitude in the Upper Colorado River Basin...................................................... 26

12. Map showing watersheds and average discharges of the Green and Colorado Rivers upstream from Lees Ferry, Arizona ............................. 28

13. Graph showing total monthly discharges of the Colorado River below Glenwood Springs, Colorado, and the Green River near

Green River, Wyoming, during water year 1984, and for the Colorado River at Lees Ferry, Arizona, during water year 1982....................... 30
VIII CONTENTS

Page 

14-18. Maps showing:

14. Generalized geology of the Upper Colorado River Basin and vicinity..................................................................................................... B31

15. Distribution of Precambrian rocks in the Upper Colorado River Basin.................................................................................................... 32

16. Distribution and thickness of the Paleozoic rocks in the Upper Colorado River Basin............................................................................ 33

17. Lithology of the Mesozoic rocks in contact with Paleozoic rocks in the Upper Colorado River Basin................................................... 35

18. Thickness of the Mesozoic and Tertiary rocks above the Paleozoic rocks in the Upper Colorado River Basin...................................... 36

19. Diagram showing range in typical permeability and hydraulic-conductivity values of sedimentary rocks....................................................... 39

20. Plots showing frequency distribution of porosity in Paleozoic sedimentary rocks of the Upper Colorado River Basin ................................... 40

21. Diagram showing relation of porosity to variations in the composition and texture of Paleozoic sedimentary rocks of the

Upper Colorado River Basin............................................................................................................................................................................... 41

22. Plots showing frequency distribution of pore-scale permeability in Paleozoic sedimentary rocks of the Upper Colorado

River Basin...................................................................................^ 42

23. Diagram showing relation of pore-scale permeability to variations in the composition and texture of Paleozoic rocks of

the Upper Colorado River Basin......................................................................................................................................................................... 43

24. Plots showing relation of pore-scale permeability to depth below land surface in the Redwall-Leadville zone of the Madison

aquifer and Weber-De Chelly zone of the Canyonlands aquifer........................................................................................................................ 44

25. Map showing thickness and lithology of the Flathead aquifer........................................................................................................................... 45

26. Plots showing relation of geophysically determined porosity to depth below land surface in the Sawatch Quartzite near

Eagle, Colorado..........................................................................................................^.......^^ 46

27-29. Maps showing:

27. Transmissivity distribution in the Flathead aquifer in the Upper Colorado River Basin and vicinity...................................................... 47

28. Thickness and lithology of the Gros Ventre confining unit...................................................................................................................... 49

29. Thickness, lithology, and unit-averaged hydraulic conductivity of the Bighorn aquifer.......................................................................... 51

30. Plot showing relation of geophysically determined porosity to depth below land surface in the Bighorn Dolomite near

Big Piney. Wyoming..........................................................................................................................................................................^ 53

31. Plot showing relation of porosity to pore-scale permeability in dolomite samples from the Muav Limestone................................................. 53

32. Map showing thickness and lithology of the Elbert-Parting confining unit....................................................................................................... 54

33. Plot showing frequency distribution of porosity in samples of dolomite and sandstone from the Elbert Formation......................................... 55

34. Map showing estimated distribution of unit-averaged porosity in the Elbert-Parting confining unit................................................................ 57

35-37. Plots showing:

35. Frequency distribution of pore-scale permeability in samples of dolomite and sandstone from the Elbert Formation ........................... 58

36. Relation of porosity to pore-scale permeability in sandstone samples from the Elbert Formation .......................................................... 59

37. Frequency distribution of hydraulic conductivity in the Elbert Formation............................................................................................... 59

38. Map showing estimated areal distribution of unit-averaged hydraulic conductivity in the Elbert Formation................................................... 60

39. Map showing estimated distribution of composite transmissivity in the Elbert Formation ............................................................................... 61

40. Plot showing frequency distribution of yields from the Elbert-Parting confining unit...................................................................................... 62

41. Map showing thickness and lithology of the Redwall-Leadville zone of the Madison aquifer.......................................................................... 63

42-48. Plots showing:

42. Frequency distribution of porosity in samples of limestone and dolomite from the Redwall-Leadville zone of

the Madison aquifer...............................................................................................................................^^ 64

43. Relation of geophysically determined porosity to depth below land surface in component geologic units of the

Redwall-Leadville zone of the Madison aquifer....................................................................................................................................... 66

44. Relation of porosity to pore-scale permeability in samples of limestone and dolomite from the Redwall-Leadville

zone of the Madison aquifer...................................................................................................................................................................... 67

45. Frequency distribution of hydraulic conductivity in limestone and dolomite intervals of the Redwall-Leadville zone

of the Madison aquifer .............................................................................................................................................................................. 68

46. Relation of the hydraulic conductivity of the Madison Limestone to depth below land surface in boreholes at the

Whiterocks River damsite. Utah ............................................................................................................................................................... 69

47. Head recovery in well OX-5 (NMB44-07-3 Icbd4 ) during "airlift test" of Leadville Limestone at Ouray, Colorado,

July 15, 1987.......................................................................................................................^^ 70

48. Frequency distribution of yields from the Redwall-Leadville zone of the Madison aquifer.................................................................... 71

49. Map showing thickness and lithology of the Darwin-Humbug zone of the Madison aquifer............................................................................ 73

50. Map showing thickness, lithology, and unit-averaged hydraulic conductivity of the Belden-Molas subunit of the Four

Corners confining unit........................................................................................................................................................................................ 75

51. Plot showing frequency distribution of porosity in carbonate rocks and shale from the Hermosa Formation................................................... 76

52. Map showing estimated distribution of unit-averaged porosity in the Belden-Molas subunit of the Four Corners

confining unit...................................................................................................................................................................................................... 77
CONTENTS IX

Page 

53-56. Plots showing:

53. Frequency distribution of pore-scale permeability in samples of shale from the Hermosa Formation.................................................... B78

54. Residual drawdown in well DH-13 (SC08-84-07caa) at Ruedi Dam site, Colorado, during bailing test of Belden

Formation in March 1963 ......................................................................................................................................................................... 78

55. Frequency distribution of hydraulic conductivity in the Belden-Molas subunit of the Four Corners confining unit.............................. 79

56. Frequency distribution of yields from the Belden-Molas subunit of the Four Corners confining unit.................................................... 80

57. Map showing thickness and lithology of the Paradox-Eagle Valley subunit of the Four Corners confining unit............................................ 81

58. Plot showing frequency distribution of porosity in carbonate rocks, sandstone, and anhydrite from the Paradox-Eagle Valley

subunit of the Four Corners confining unit......................................................................................................................................................... 83

59. Map showing estimated distribution of unit-averaged porosity in the Paradox-Eagle Valley subunit of the Four Corners

confining unit...................................................................................................................................................................................................... 84

60-63. Plots showing:

60. Relation of porosity to pore-scale permeability in limestone samples from the Paradox-Eagle Valley subunit

of the Four Corners confining unit............................................................................................................................................................ 85

61. Frequency distribution of local-scale permeability in the Paradox-Eagle Valley subunit of the Four Corners

confining unit............................................................................................................................................................................................ 86

62. Frequency distribution of hydraulic conductivity in the Paradox-Eagle Valley subunit of the Four Corners

confining unit...........................................................................................................................................................................................^ 87

63. Frequency distribution of yields from the Paradox-Eagle Valley subunit of the Four Corners confining unit....................................... 89

64. Map showing thickness and lithology of the Cutler-Maroon zone of the Canyonlands aquifer........................................................................ 91

65-68. Plots showing:

65. Frequency distribution of porosity in samples of sandstone and carbonate rocks from the Cutler-Maroon zone

of the Canyonlands aquifer....................................................................................................................................................................... 92

66. Relation of geophysically determined porosity to depth below land surface and lithology in component geologic

units of the Cutler-Maroon zone of the Canyonlands aquifer................................................................................................................... 94

67. Relation of porosity to pore-scale permeability in sandstone samples from the Cutler-Maroon zone of the

Canyonlands aquifer................................................................................................................................................................................. 95

68. Frequency distribution of local-scale permeability in the Cutler-Maroon zone of the Canyonlands aquifer........................................... 96

69. Map showing distribution of local-scale sandstone permeability in the Cutler-Maroon zone of the Canyonlands aquifer

in southeastern Utah and southwestern Colorado............................................................................................................................................... 97

70-73. Plots showing:

70. Frequency distribution of hydraulic conductivity in the Cutler-Maroon zone of the Canyonlands aquifer................................................ 98

71. Relation of hydraulic conductivity to depth below land surface and lithology in component geologic units of the

Cutler-Maroon zone of the Canyonlands aquifer in northwestern Colorado............................................................................................ 100

72. Residual drawdown in well DH-16 (SC08-84-07bdc) at Ruedi Dam site, Colorado, during bailing test of Maroon

Formation in April 1963 ........................................................................................................................................................................... 101

73. Frequency distribution of yields from the Cutler-Maroon zone of the Canyonlands aquifer................................................................... 102

74. Map showing thickness and lithology of the Weber-De Chelly zone of the Canyonlands aquifer.................................................................... 103

75-78. Plots showing:

75. Frequency distribution of porosity in samples of sandstone from the Weber-De Chelly zone of the Canyonlands aquifer.................... 104

76. Relation of geophysically determined porosity to depth below land surface in component geologic units of the

Weber-De Chelly zone of the Canyonlands aquifer: A, Tensleep Sandstone; B. Weber Sandstone; C, White Rim Sandstone;

D. De Chelly Sandstone............................................................................................................................................................................ 106

77. Frequency distribution of local-scale permeability in the Weber-De Chelly zone of the Canyonlands aquifer...................................... 107

78. Relation of porosity to pore-scale permeability in sandstone samples from the Weber-De Chelly zone of the Canyonlands aquifer.... 107

79. Map showing estimated distribution of unit-averaged pore-scale permeability in the Weber-De Chelly zone of

the Canyonlands aquifer in southeastern Utah, northeastern Arizona, and northwestern New Mexico ............................................................ 108

80. Plot showing frequency distribution of hydraulic conductivity in the Weber-De Chelly zone of the Canyonlands aquifer............................. 109

81. Map showing estimated storativity distribution in the Weber-De Chelly zone of the Canyonlands aquifer..................................................... Ill

82. Plot showing frequency distribution of yields from the Weber-De Chelly zone of the Canyonlands aquifer................................................... 112

83. Map showing thickness and lithology of the Park City-State Bridge zone of the Canyonlands aquifer .......................................................... 113

84-88. Plots showing:

84. Frequency distribution of porosity in samples of sandstone, dolomite, and limestone from the Park City-State

Bridge zone of the Canyonlands aquifer................................................................................................................................................... 114

85. Frequency distribution of pore-scale permeability in the Park City-State Bridge zone of the Canyonlands aquifer.............................. 116

86. Relation of porosity to pore-scale permeability in samples of sandstone and dolomite from the Park City-State

Bridge zone of the Canyonlands aquifer................................................................................................................................................... 117

87. Frequency distribution of hydraulic conductivity in the Park City-State Bridge zone of the Canyonlands aquifer................................ 118

88. Frequency distribution of yields from the Park City-State Bridge zone of the Canyonlands aquifer...................................................... 119

89. Geologic section showing head differences between the Canyonlands aquifer and the Madison aquifer of the Four Corners

aquifer system in southeastern Utah................................................................................................................................................................... 120
CONTENTS

90-92. Maps showing:

90. Concentration of dissolved solids in water from the Redwall-Leadville zone of the Madison aquifer.................................................... B122

91. Concentration of dissolved solids in water from the Weber-De Chelly zone of the Canyonlands aquifer.............................................. 123

92. Recharge and discharge areas for the Paleozoic rocks in the Upper Colorado River Basin..................................................................... 124

93. Generalized geologic section across the White River Plateau showing ground-water circulation in the Paleozoic rocks ................................ 129

94. Plot of log against temperature for water from the Leadville Limestone discharging from the Redstone 21-9 well at

Glenwood Springs, Colorado.............................................................................................................................................................................. 130

95. Graph showing comparison of major ion chemistry modeled by CHILLER and analyzed ground water from Leadville Limestone

at Glenwood Springs, Colorado.......................................................................................................................................................................... 131

96. Plots showing recorded discharges of thermal springs at Ouray, Colorado, 1987 to 1988................................................................................ 132

97. Geologic section from the Piceance Basin to the White River Plateau indicating the potentiometric surface for the Canyonlands

aquifer and potential spring locations................................................................................................................................................................. 135

98. Photograph showing Kendall Warm Springs (SB39-110-36) issuing from the Phosphoria Formation and flowing over terrace

deposits into the Green River north of Pinedale, Wyoming............................................................................................................................... 136

99. Photograph showing Placerville Warm Spring (NMB44-1 l-34ddd) issuing from travertine deposits at the base of an outcrop

of the Cutler Formation at Placerville, Colorado................................................................................................................................................ 137

100. Schematic representation of ground-water movement with respect to stratigraphy in the Kaibab Plateau in Arizona..................................... 139

101. Schematic section showing potential spring locations on the flanks of an uplifted area ................................................................................... 140

TABLES

TABLE 1. Hydrogeologic nomenclature for Precambrian, Paleozoic, and Mesozoic rocks in the Upper Colorado River Basin

used in Regional Aquifer-System Analysis reports............................................................................................................................................ B3

2. Types of aquifer tests and methods of analysis used in determining hydrologic properties of Paleozoic rocks in the

Upper Colorado River Basin .............................................................................................................................................................................. 7

3. Equations relating porosity to pore-scale permeability for hydrogeologic units composed of Paleozoic rocks in the

Upper Colorado Basin ......................................................................................................................................................................................^ 8

4. Comparison of closely obtained drill-stem test and core-permeability values for Paleozoic rocks in the Upper Colorado

River Basin .................................................................................................................................................................................^ 12

5. Summary of lithologic and hydrologic properties of the hydrogeologic units composed of Paleozoic rocks in the Upper

Colorado River Basin ......................................................................................................................................................................................^ 37

6. Porosity and pore-scale permeability statistics for the Bighorn aquifer............................................................................................................. 52

7. Porosity and pore-scale permeability statistics for the Elbert-Parting confining unit........................................................................................ 56

8. Porosity and pore-scale permeability statistics for the Redwall-Leadville zone of the Madison aquifer.......................................................... 65

9. Porosity and pore-scale permeability statistics for the Paradox-Eagle Valley subunit of the Four Corners confining unit.............................. 82

10. Hydraulic conductivity of the Paradox Member of the Hermosa Formation in Borehole GD-1 (SLD30-21-21ddd)..................................... 88

11. Hydraulic conductivity of the Paradox Member of the Hermosa Formation in Borehole DOE-1 (SLD23-20-05badi).................................. 88

12. Porosity and pore-scale permeability statistics for the Cutler-Maroon zone of the Canyonlands aquifer......................................................... 93

13. Values of hydraulic conductivity in the Cutler-Maroon zone of the Canyonlands aquifer determined by pressure-injection

tests at dam sites in northwestern Colorado ....................................................................................................................................................... 99

14. Porosity and pore-scale permeability statistics for the Weber-De Chelly zone of the Canyonlands aquifer..................................................... 105

15. Values of hydraulic conductivity and transmissivity in the Weber-De Chelly zone of the Canyonlands aquifer determined

from pumping, flowing-well, and injection tests in the Upper Colorado River Basin and vicinity................................................................... 110

16. Porosity and pore-scale permeability statistics for the Park City-State Bridge zones of the Canyonlands aquifer........................................... 115

17. Estimated average annual volumes of precipitation and ground-water recharge, 1941-70, in the northern Uinta Basin and

Uinta Mountains ......................................................................................................................................................................................^ 125

18. Estimated average annual volumes of precipitation and ground-water recharge, 1931-80, in the Upper Colorado River

Basin, excluding the San Juan Basin.................................................................................................................................................................. 125

19. Estimated annual interbasin flow contributing recharge to Paleozoic rocks in the Upper Colorado River Basin............................................. 127

20. December 1986 water production from oil and gas fields where the principal reservoir is in Paleozoic rocks of the Upper

Colorado River Basin ......................................................................................................................................................................................... 128

21. Measured ground-water outflows to streams from Paleozoic rocks in the Upper Colorado River Basin, excluding the San Juan Basin......... 141

22. Summary of known discharges from Paleozoic rocks to streams, springs, and wells in the Upper Colorado River Basin, excluding

the San Juan Basin, as of 1988 ..................................................................................................................................................................... 142

23. Ground-water consumption by evapotranspiration and seepage in areas where Paleozoic rocks are at or near land surface in the

Upper Colorado River Basin .............................................................................................................................................................................. 143

24. Estimated ground-water budget for the Paleozoic rocks of the Upper Colorado River Basin, excluding the San Juan Basin.......................... 144
CONTENTS XI

CONVERSION FACTORS AND VERTICAL DATUM

This report uses inch-pound units as the primary system for all numerical data except dissolved-solids concentrations. Dissolved-solids concentrations are 

given in milligrams per liter (mg/L), a metric unit approximately equivalent to parts per million in the inch-pound system at concentrations of less than 

7,000 mg/L. Inch-pound units can be converted to metric units with the following multiplication factors:

Multiply By To obtain

acre (acre)

acre-foot (acre-ft)

acre-foot per year (acre-ft/yr)

barrel (42 gallons) per day

barrel per day per foot (bbl/d/ft)

cubic foot per second (ft3/s)

cubic foot per second per mile (ft3/s/mi)

cubic foot per second per square mile (ft3/s/mi2 )

cubic foot per day (ft3/d)

foot (ft)

foot per day (ft/d)

foot squared per day (ft2/d)

gallon (gal)

gallon per minute (gal/min) 

inch (in.)

inch per year (in/yr) 

mile (mi)

mile per year (mi/yr)

pound per square inch (lb/in")

pound per cubic inch (lb/in3)

square foot (ft )

square inch per pound (in2/lb)

square mile (mi )

0.4047

0.001233

0.001233

0.00184

0.00604

0.02832

0.01760

0.01093

0.02832

0.3048

0.3048

0.0929

3.785

0.06308

25.4

25.4

1.609

1.609

0.07037

0.02768

0.0929

14.2

2.59

square hectometer

cubic hectometer

cubic hectometer per year

liter per second

liter per second per meter

cubic meter per second

cubic meter per second per kilometer

cubic meter per second per square kilometer

cubic meter per day

meter

meter per day

meter squared per day

liter

liter per second

millimeter

millimeter per year

kilometer

kilometer per year

kilogram per square centimeter

kilogram per cubic centimeter

square meter

square centimeter per kilogram

square kilometer

Temperature in degrees Fahrenheit (°F) can be converted to temperature in degrees Celsius (°C) by the following equation:

°C = 5/9(°F-32)

A millidarcy (md) is 0.987 x 10 11 centimeter squared.

National Geodetic Vertical Datum of 1929 (NGVD of 1929 A geodetic datum derived from a general adjustment of the first-order level nets of both the United

States and Canada, formerly called "Sea Level Datum of 1929."
REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN IN ARIZONA, COLORADO, 

NEW MEXICO, UTAH, AND WYOMING, EXCLUDING SAN JUAN BASIN

HYDROLOGIC PROPERTIES AND GROUND-WATER 

FLOW SYSTEMS OF THE PALEOZOIC ROCKS IN THE

UPPER COLORADO RIVER BASIN IN ARIZONA,

COLORADO, NEW MEXICO, UTAH, AND WYOMING,

EXCLUDING THE SAN JUAN BASIN

By ARTHUR L. GELDON

"All winter long snow falls on its mountain-crested rim, filling the gorges, half burying the forests, and 

covering the crags and peaks with a mantle woven by the winds from the waves of the sea. When the summer 

sun comes this snow melts and tumbles down the mountainsides in millions of cascades. A million cascade 

brooks unite to form a thousand torrent creeks; a thousand torrent creeks unite to form half a hundred rivers 

beset with cataracts; half a hundred roaring rivers unite to form the Colorado, which rolls, a mad, turbid stream, 

into the Gulf of California."

John Wesley Powell, 

The Exploration of the Colorado River and Its Canyons

ABSTRACT

The hydrologic properties and ground-water flow systems of Paleozoic 

sedimentary rocks in the Upper Colorado River Basin were investigated under 

the Regional Aquifer-System Analysis (RASA) program of the U.S. Geological 

Survey in anticipation of the development of water supplies from bedrock aquifers to fulfill the region's growing water demands. The study area, in parts of 

Arizona. Colorado. New Mexico, Utah, and Wyoming, covers about 

100,000 square miles. It includes parts of four physiographic provinces the 

Middle Rocky Mountains, Wyoming Basin, Southern Rocky Mountains, and 

Colorado Plateaus. A variety of landforms. including mountains, plateaus, 

mesas, cuestas, plains, badlands, and canyons, are present. Altitudes range from 

3,100 to 14,500 feet. Precipitation is distributed orographically and ranges from 

less than 6 inches per year at lower altitudes to more than 60 inches per year in 

some mountainous areas. Most of the infrequent precipitation at altitudes of less 

than 6,000 feet is consumed by evapotranspiration. The Colorado and Green 

Rivers are the principal streams; the 1964-82 average discharge of the Colorado 

River where it leaves the Upper Colorado River Basin is 12.170 cubic feet per 

second (a decrease of 5,680 cubic feet per second since construction of Glen 

Canyon Dam in 1963).

On the basis of their predominant lithologic and hydrologic properties, the 

Paleozoic rocks are classified into four aquifers and three confining units. The 

Flathead aquifer. Gros Ventre confining unit. Bighorn aquifer, Elbert-Parting 

confining unit, and Madison aquifer (Redwall-Leadville and Darwin-Humbug 

zones) make up the Four Corners aquifer system. A thick sequence, composed 

mostly of Mississippian and Pennsylvania!! shale, anhydrite, halite, and 

carbonate rocks the Four Corners confining unit (Belden-Molas and ParadoxEagle Valley subunits) overlies the Four Corners aquifer system in most areas

and inhibits vertical ground-water flow between the Four Corners aquifer 

system and the overlying Canyonlands aquifer. Composed of the uppermost 

Paleozoic rocks, the Canyonlands aquifer consists, in ascending order, of the 

Cutler-Maroon, Weber-De Chelly, and Park City-State Bridge zones. The 

Paleozoic rocks are underlain by a basal confining unit consisting of 

Precambrian sedimentary, igneous, and metamorphic rocks and overlain 

throughout most of the Upper Colorado River Basin by the Chinle-Moenkopi 

confining unit, which consists of Triassic formations composed mostly of shale.

The largest values of porosity, permeability, hydraulic conductivity, transmissivity, and artesian yield are exhibited by the Redwall-Leadville zone of the 

Madison aquifer and the Weber-De Chelly zone of the Canyonlands aquifer. 

The former consists almost entirely of Devonian and Mississippian carbonate 

rocks; the latter consists mostly of Pennsylvania!! and Permian quartz sandstone. Unit-averaged porosity in hydrogeologic units composed of Paleozoic 

rocks ranges from less than 1 to 28 percent. Permeability ranges from less than 

0.0001 to 3,460 millidarcies. Unit-averaged hydraulic conductivity ranges from 

0.000005 to 200 feet per day. The composite transmissivity of Paleozoic rocks 

ranges from 0.0005 to 47.000 feet squared per day. Artesian yields to wells and 

springs (excluding atypical springflows) from these hydrogeologic units range 

from less than 1 to 10.000 gallons per minute. The permeability and watersupply capabilities of all hydrogeologic units progressively decrease from 

uplifted areas to structural basins.

Recharge to the Paleozoic rocks is provided by direct infiltration of precipitation, leakage from streams, and ground-water inflows from structurally 

continuous areas west and north of the Upper Colorado River Basin. The total 

recharge available from ground-water systems in the basin from direct precipitation and stream leakage is estimated to be 6,600,000 acre-feet per year. 

However, little of this recharge directly enters the Paleozoic rocks. The recharge 

from interbasin flow is estimated to be about 1,000 acre-feet per year.

Bl
REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

Within the Four Corners aquifer system and Canyonlands aquifer, ground 

water moves from peripheral and internal highlands to the eastern Great Divide 

Basin, the confluence of the Yampa and Green Rivers, the San Juan Basin, and the 

confluence of the Colorado and Little Colorado Rivers (in the Lower Colorado 

River Basin). Estimated rates of lateral ground-water movement within the 

Redwall-Leadville zone of the Madison aquifer and the Weber-De Chelly zone of 

the Canyonlands aquifer range from 0.000001 to 600 feet per day.

Water in the Paleozoic rocks discharges to streams, springs, and wells, is 

consumed by evapotranspiration where the Paleozoic rocks are at or near land 

surface, rises into Mesozoic and Tertiary rocks in structural basins along subregional flow paths, or flows out of the Upper Colorado River Basin into adjacent hydrologic basins. Total discharge to springs and streams is estimated to 

equal or exceed 810,000 acre-feet per year. Total withdrawals of water from 

water, oil. and gas wells is less than 82,000 acre-feet per year. Outflow to the 

Lower Colorado River Basin, as determined from the combined discharge of 

springs issuing from Paleozoic rocks in Marble Canyon and the canyon of the 

Little Colorado River, is less than 170,000 acre-feet per year. Outflows to the 

Hanna and San Juan Basins, losses to evapotranspiration. and leakage to 

Mesozoic and Tertiary rocks cannot be quantified at present.

INTRODUCTION

In anticipation of increased water use for the development 

of coal and oil resources and to meet the needs of an expanding 

population, the U.S. Geological Survey (USGS) from 1981 to 

1990 undertook a systematic appraisal of the ground-water 

resources of the Upper Colorado River Basin (UCRB). This 

study, known as the Upper Colorado River Basin Regional 

Aquifer-System Analysis (UCRB-RASA), was part of a nationwide investigation of regional aquifers by the USGS (Sun, 

1986). According to Taylor and others (1983, 1986), specific 

objectives of the UCRB-RASA were:

1. Identification of aquifers and confining units among consolidated sedimentary rocks of Cambrian to Tertiary age;

2. Determination of the extent thickness, and hydrologic characteristics of aquifers and confining units;

3. Determination of the water-supply potential of aquifers;

4. Determination of the geochemical characteristics of the 

ground water;

5. Analyses of the regional ground-water flow systems under 

steady-state conditions; and

6. Analysis of the flow-system responses to hypothetical 

ground-water withdrawal or injection.

The results of the UCRB study are presented in USGS 

Professional Paper 1411, which consists of several chapters. 

This report, Professional Paper 1411-B, briefly describes the 

geology of the Paleozoic rocks in the UCRB and extensively 

describes the hydrologic properties and ground-water flow 

systems of these rocks. This report synthesizes geological, 

geochemical, geophysical, and hydrological information from 

numerous published reports and files of unpublished data. Some 

original geochemical and aquifer-test data were incorporated 

into the study to support interpretations. Sources for geologic 

material used in this report include unpublished petroleum 

industry borehole logs prepared by the American Stratigraphic 

Company, lithologic logs provided by the Bureau of

Reclamation (written commun., 1983-85), and measured stratigraphic sections contained in published reports cited herein. 

Sources for hydrologic data used in this report include unpublished drill-stem test, geophysical, and core data compiled by 

Petroleum Information Corporation, unpublished injection-test 

information supplied by the Bureau of Reclamation (written 

commun., 1983-85), unpublished pumping and bailing test 

information compiled by the Colorado Division of Water 

Resources, State Engineer's Office, unpublished well and 

spring data provided by the City of Ouray (written commun., 

1988), unpublished material in files of the USGS, and published 

reports cited herein.

Within this report, hydrologic properties are discussed for 

the Paleozoic rocks in general and by hydrogeologic unit. A 

hydrogeologic unit for the purposes of this study is defined as a 

group of geologic formations and parts of formations that are 

related stratigraphically and share similar or related lithologic 

and hydrologic properties. As indicated in table 1, the Paleozoic 

rocks in this study were classified into 11 hydrogeologic 

units four aquifers, three confining units, and subdivisions of 

aquifers and confining units. This classification was based on 

the predominant characteristics of each hydrogeologic unit, 

because the lithology of most units varies extensively 

throughout the UCRB. An aquifer for the purposes of this study 

is defined as a group of formations and parts of formations that 

transmit water to wells and springs throughout most of the 

UCRB. Confining units consist of a group of formations and 

parts of formations composed of heterogeneous rock types that 

generally tend to inhibit vertical ground-water movement but 

locally may transmit water.

The classification of hydrogeologic units used in this report 

differs somewhat from previous reports on the hydrogeology of 

the Paleozoic rocks in the UCRB that were published during the 

UCRB-RASA (table 1). The current classification scheme 

represents: (1) An evolution of thought based on increasing 

amounts of hydrologic and geologic information that became 

available as the RASA investigation progressed; and (2) an 

attempt to accommodate guidelines for naming aquifers and 

confining units in regional-scale studies of complex groundwater systems that were adopted by the USGS several years 

after the UCRB-RASA began (Laney and Davidson, 1986).

LOCATION OF STUDY

The UCRB, as defined by the Colorado River Compact of 

1922, encompasses the drainages of the Green and Colorado 

Rivers above the mouth of the Paria River at Lees Ferry, Ariz., 

and the internally drained Great Divide Basin of Wyoming. The 

UCRB includes about 113,500 mi2 of land in western Colorado, 

eastern Utah, southwestern Wyoming, northeastern Arizona, 

and northwestern New Mexico (pi. 1). Because the San Juan 

Basin, an area of about 14,600 mi2 , was excluded for separate 

investigation, this report does not include most of the land in 

New Mexico and some of the land in southwestern Colorado
INTRODUCTION B3

TABLE 1. Hydrogeologic nomenclature for Precambrian, Paleozoic, and Mesozoic rocks in the Upper Colorado River Basin

used in Regional Aquifer-System Analysis reports

Component geologic units

Chinle Formation, Dolores Formation, 

Moenkopi Formation, Woodside Shale, 

and Dinwoody Formation; upper State 

Bridge and Goose Egg Formations

Kaibab, Toroweap, Park City, and 

Phosphoria Formations; lower State 

Bridge and Goose Egg Formations

Tensleep. Weber-De Chelly, and Coconino 

Sandstones; White Rim Sandstone 

(ofBaars. 1962); Wells Formation; 

Fryingpan and Schoolhouse Members 

of Maroon Formation (Johnson, 1989; 

Johnson and others, 1990)

Ranchester Limestone Member of 

Amsden Formation; upper member of 

Hermosa Formation; Gothic Formation 

(of Langenheim, 1952): Minturn, 

Morgan, and Rico Formations; main 

body of Maroon Formation, undifferentiated Cutler and Supai Formations; 

Halgaito Shale, Elephant Canyon 

Formation, Cedar Mesa Sandstone, 

and Organ Rock Shale of Cutler Group 

(Baars, 1962); Wescogame Formation 

and Esplanade Sandstone of Supai 

Group (McKee, 1982); Hermit Shale

Moffat Trail Limestone Member of 

Amsden Formation, Paradox Member 

of Hermosa Formation, Eagle Valley 

Evaporite, Round Valley Limestone, 

Manakacha Formation of Supai Group

Horseshoe Shale Member of Amsden 

Formation, Doughnut Shale, Surprise 

Canyon Formation, Watahomigi 

Formation of Supai Group, Molas 

Formation, lower member of Hermosa 

Formation, Belden Formation

Humbug Formation. Bull Ridge 

Member of Madison Limestone, 

Darwin Sandstone Member of 

Amsden Formation, upper 

Mission Canyon Limestone

Dyer Dolomite, Ouray Limestone, Oilman 

Sandstone, Leadville Limestone, main 

bodies of Madison and Lodgepole 

Limestones, lower Mission Canyon 

Limestone, Redwall Limestone

Elbert, Parting, Darby, and Temple Butte 

Formations, Cottonwood Canyon 

Member of Lodgepole and Madison 

Limestones

Mauv Limestone and equivalents, Maxfield 

Limestone, Lynch Dolomite Gallatin 

Limestone, Peerless and Dotsero 

Formations, Manitou Dolomite, Harding 

Sandstone. Fremont Limestone. Bighorn 

Dolomite, Ophir Shale, Bright Angel 

Shale and equivalents, Gros Ventre 

Formation, upper Lodore Formation

Tintic Quartzite, Tapeats Sandstone and 

equivalents, Flathead Sandstone, lower 

Paleozoic Lodore Formation. Sawatch 

Quartzite, and Ignacio Quartzite

Red Creek Quartzite, granitic and 

metamorphic rocks; Uncompahgre 

Formation, Uinta Mountain Group, 

Unkar Group, Nankoweap Formation, 

and Chuar Group

Hydrogeologic 

unit of Taylor 

and others 

(1986)

Lower Mesozoic 

confining layers

Upper Paleozoic 

aquifers and 

confining layers

Middle Paleozoic 

aquifers

Lower Paleozoic 

aquifers and 

confining layers

Basal Paleozoic 

aquifer

Not considered

Hydrogeologic 

unit of LindnerLunsford 

and others 

(1985)

Lower Mesozoic 

confining layers

Upper Paleozoic 

aquifers

Upper Paleozoic 

confining layers

Middle Paleozoic 

aquifers

Lower Paleozoic 

aquifers and 

confining layers

Basal Paleozoic 

aquifer

Not considered

Hydrogeologic 

unit of Weiss 

(1990)

Not considered

Sandstone and red 

bed aquifer

Not considered

Limestone and 

dolomite aquifer

Not considered

Hydrostratigraphic 

unit of Geldon 

(1986, 1989a,b, c, d)

Triassic confining layer

Permian shale and 

carbonate rocks 

hydrostratigraphic 

unit

Pennsylvanian 

and Permian 

sandstone hydrostratigraphic unit

Pennsylvanian 

and Permian 

red beds and 

carbonate rocks 

hydrostratigraphic 

unit

Mississippian and 

Pennsylvanian 

carbonate rocks 

and evaporites 

hydrostratigraphic 

unit1

Mississippian and 

Pennsylvanian 

shale and 

carbonate rocks 

hydrostratigraphic 

unit

Mississippian 

carbonate and 

clastic rocks 

hydrostratigraphic 

unit

Denvonian and 

Mississippian 

carbonate rocks 

hydro stratigraphic 

unit

Canyonlands aquifer

confining Four Cornes unit

Madison aquifer

Devonian carbonate 

and clastic rocks 

hydrostratigraphic 

unit

Cambrian and Ordovician 

carbonate rocks hydrostratigraphic unit

Cambrian shale hydrostratigraphic unit

Cambrian sandstone 

hydrostratigraphic unit

Precambrian confining 

layer

Nomenclature in this paper

Hydrogeologic 

unit

Confining unit 

consisting of 

Mesozoic rocks 

(ChinleMoenkopi 

confining unit)

Park City-State 

Bridge zone

Weber-De Chelly 

zone

Cutler-Maroon zone

Paradox-Eagle 

Valley subunit

Belden-Molas 

subunit

Darwin-Humbug 

zone

Redwall-Leadville 

zone

Elbert-Parting 

confining unit

Bighorn aquifer

Gros Ventre 

confining unit

Flathead aquifer

Basal confining unit

Ground-water

system

applicable Not 

Four Corners 

aquifer 

system

Not considered

^n Geldon (1986 and 1989c), this unit is referred to as the Pennsylvanian carbonate rocks and evaporites hydrostratigraphic unit because in the area of these two reports, 

northwestern Colorado, no Mississippian rocks are included in the hydrogeologic unit.
B4 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

and northeastern Arizona that are in the UCRB. About 

100,000 mi~ of the UCRB are covered by this report. Because 

hydrogeologic interpretations in the report are based in part on 

data from areas peripheral to the UCRB, discussions in the 

report extend beyond the boundaries of the UCRB.

The UCRB, excluding the San Juan Basin, extends from 

latitude 35°46'N to latitude 43°27'N and from longitude latitude 

105x°38'W to longitude 112°19'W. The UCRB, excluding the 

San Juan Basin, has maximum dimensions of about 560 mi 

from north to south and about 320 mi from east to west.

The UCRB is sparsely inhabited. According to the 

U.S. Water Resources Council (1978, p. 5), the total population 

in the UCRB (including the San Juan Basin) in the mid-1970's 

was about 344,000. About 68 percent of this population was in 

western Colorado; 12 percent was in Wyoming; 15 percent was 

in the Unita Basin area of northeastern Utah; and the remaining 

5 percent was in the Canyonlands area of southeastern Utah (see 

pi. 1 for locations of areas mentioned). The average population 

density is about four people per square mile, but much of the 

land is uninhabited. Most of the area's population is clustered in 

the towns of Grand Junction, Montrose, Delta, Paonia, 

Glenwood Springs, Aspen, Craig, Steamboat Springs, Meeker, 

Gunnison, Cortez, and Durango, Colo.; Price, Vernal, Manila, 

Moab, Monticello, and Blanding, Utah; Rock Springs, Green 

River, Pinedale, and Kemmerer, Wyo.; Page and Kayenta, Ariz.; 

and Shiprock and Farmington, N. Mex.

PREVIOUS INVESTIGATIONS

Several comprehensive investigations of water resources in 

the UCRB preceded the present (RASA) study. Reports by 

La Rue (1916), lorns and others (1965), and Liebermann and 

others (1988) were devoted mainly to discussion of surface water. 

Surface- and ground-water data compiled for the study by lorns 

and others (1965) were published in a separate report by lorns and 

others (1964). Additional ground-water data were compiled in a 

report by Price and Waddell (1973). Price and Arnow (1974) 

discussed the general availability and quality of ground water in 

the basin, with emphasis on developing ground-water resources 

and the impacts from such development. The U.S. Water 

Resources Council (1978) compiled demographic, physiographic, climatologic, mineralogic, and water-resource data and 

analyzed water-re source use. Rouse (1967) compiled data on 

saline springs and other saline inflows to streams in the UCRB. 

Warner and others (1985) systematically determined groundwater contributions to the salinity of streams in the UCRB.

Many local ground-water investigations in the UCRB 

provided information used in this study. Areas covered by interpretive reports representative of the ground-water literature for 

the UCRB are shown in figure 1. Other reports are cited 

throughout the text and in the "Selected References" section. 

Some of the information used in this study was obtained from 

reports on the hydrogeology of areas adjacent to or near the

UCRB. In this category were reports by Metzger (1961), Akers 

and others (1962), Twenter and Metzger (1963), Akers (1964), 

Bredehoeft (1964), Whitcomb and Lowry (1968), Cooley 

(1976, 1985), Konikow( 1976), Huntoon (1983), Thayer (1983), 

Downey (1984), Kreitler and others (1985), and McCulley

(1985).

Several reports produced during the UCRB-RASA contain 

hydrologic information about the Paleozoic rocks. Taylor and 

others (1986) discussed the hydrogeologic framework of the 

UCRB. Lindner-Lunsford and others (1985) presented a generalized interpretation of the hydrogeology of Paleozoic aquifers 

in the UCRB. Geldon (1986, 1989c) characterized the hydrogeology of the Paleozoic rocks in northwestern Colorado. 

Geldon (1989a, 1989b) presented a summary of information 

contained in this report. Some of the drill-stem test data used in 

this study were obtained from a report by Teller and Chafin

(1986). Most of the hydrologic data used in the study were 

published in a report by Geldon (1989d). Weiss (1990) 

presented results of modeling studies of the Paleozoic rocks in 

the southern part of the UCRB.

SYSTEM OF NUMBERING WELLS AND SPRINGS

Wells and springs are numbered in this report according to 

the Bureau of Land Management system. The first one or two 

letters in the site-identification number represent the principal 

survey meridian. The UCRB is referenced to seven different 

meridians. Symbols adopted for these meridians in this report 

are:

G - Gila and Salt River

N - Navajo

NM - New Mexico

S - Sixth

SL - Salt Lake

U - Uintah

UT - Ute

Letters and numbers following the symbol for the principal 

survey meridian in the site-identification number refer, in 

order, to quadrant, township, range, section, quarter section, 

quarter-quarter section, quarter-quarter-quarter section, and 

number of well or spring within the smallest physical 

boundary (multiple ground-water sites within the smallest 

physical boundary are numbered consecutively). Quadrants 

and divisions of sections are labeled from A to D in a counterclockwise direction starting with the northeast quadrant or 

section division. Quadrant designations are upper case; 

section division designations are lower case. Dashes are used 

to separate township, range, and section designations. As an 

example, a well numbered SC06-89-09bdaj is the first well in 

the northeast quarter of the southeast quarter of the northwest 

quarter of Section 9, Township 6 South, Range 89 West, in the 

southwest quadrant of the Sixth principal survey meridian.
INTRODUCTION B5

BOUNDARY OF

UPPER COLORADO

HIVER 8AS!i\i

"WYOMING

Welder and

McGreevy

(19661

Berry 

(1960)

/No report coverage "~ -nX

\ i Maxwell

...~, Brogden 

Sumsion ' and Giles 

(1977)

(JRS Corporation (1982;, 1983]

EXPLANATION

Boundary of area covered 

by cited report Areas of 

overlap between adjacent 

studies arc not shown

AREA EXCLUDED 

FROM STUDY

25 50 75 100 MILES

25 50 75 100 KILOMETERS

FIGURE 1. Areas covered by ground-water reports in the Upper Colorado River Basin. (Many other interpretive and data reports 

provided ground-water information for the study area. Reports shown here are either the most comprehensive for the areas they 

cover or are representative of other reports covering the same area, as of 1987.)
B6 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

ACKNOWLEDGMENTS

The author is indebted to Michael Galloway, Terra Therma, 

Inc.; Donald Tail, formerly of ARCO; Charles (Chuck) Spencer, 

U.S. Geological Survey Oil and Gas Branch; Thomas 

Zancanella and William Lorah, Wright Water Engineers; 

Redstone Corporation; Glenwood Hot Springs Lodge and Pool; 

Bureau of Reclamation, Grand Junction, Denver, and Salt Lake 

City offices; the Colorado Division of Water Resources, State 

Engineer's Office (Denver); and David Vince, Town Planner for 

the City of Ouray, Colo., for furnishing information and 

assistance in the preparation of this report. The author also 

would like to thank Steven Meyer, formerly with the 

U.S. Geological Survey, for his work in compiling data and 

carrying out other tedious assignments essential to the completion of this investigation.

METHODS OF ANALYSIS

Studying the hydrogeology of the UCRB required extensive 

searches for sparsely distributed data and diverse approaches to 

data analysis. Methods of analysis used to describe hydrologic 

properties are described thoroughly in this section.

POROSITY

Porosity values were obtained by laboratory methods and by 

interpretation of geophysical logs. In the laboratory, porosity is 

determined by saturating, weighing, oven drying, and 

reweighing a sample and then converting the weight of the 

water lost in drying the sample to the total sample volume 

(Freeze and Cherry, 1979, p. 337). Most of the 7,665 laboratorydetermined values of porosity used in this study were determined from plugs of core taken from boreholes. These values 

were obtained from unpublished data files of Petroleum 

Information Corporation. Six of the porosity values were determined from outcrop samples; this information was reported by 

Hood (1976) and Hood and Patterson (1984).

Porosity also can be determined from sonic, bulk-density, or 

neutron logs. Sonic logs record the transit time of an acoustic 

pulse traveling from a probe through the formation and back to a 

receiver. Bulk-density logs record the intensity of induced 

gamma radiation backscattered and absorbed by a formation. 

Neutron logs record the intensity of neutron radiation deflected 

by a formation. Logging principles and procedures are described 

by Schlumberger Limited (1972, 1974), Schlumberger Well 

Services (1984), and Keys (1988). Fox and others (1975) used 

sonic logs calibrated against a curve of interval transit time versus 

measured porosity in boreholes in the Bighorn, Wind River, and 

greater Green River Basins. Data for 11 boreholes in the greater 

Green River Basin were integrated into this study. As part of the 

RASA study, Gregory Wetherbee and William Van Liew 

(U.S. Geological Survey, written commun., 1986) used sonic,

bulk-density, and neutron logs, in combination, to determine 

porosity in 99 borehole intervals; required physical parameters of 

the sandstone and carbonate rocks studied were based on calibration of geophysical logs against measured core-porosity values 

from about 20 boreholes.

To determine the regional distribution of porosity within a 

hydrogeologic unit, unit-averaged porosity values at grid 

centers on a 10-mi x 10-mi grid or in individual boreholes 

were contoured. Unit-averaged porosity values were calculated 

from the median porosity of each rock type present at the grid 

center or in the borehole and the proportion of the total thickness represented by each rock type. In contouring the unitaveraged values, sparsely distributed measurements of 

geophysically determined or laboratory-determined porosity in 

borehole intervals were used as a guide.

No information was available to determine whether reported 

values of porosity used in this study were total or effective. 

Considering the methods used to obtain these values, all values 

were assumed to be effective porosity.

PERMEABILITY

Permeability and hydrologic properties that can be calculated from permeability, such as hydraulic conductivity, are 

scale-dependent (Dagan, 1986). Values of permeability or 

hydraulic conductivity differing by orders of magnitude 

commonly are obtained depending on whether laboratory tests, 

field tests, or numerical modeling methods are used. For 

example, Bredehoeft and others (1983) found that field (slug 

test) and laboratory measurements of the hydraulic conductivity 

of Cretaceous shale in South Dakota could be one to three 

orders of magnitude smaller than values of hydraulic conductivity indicated by numerical modeling. At Gibson Dome, in 

southeastern Utah, regional finite-difference modeling indicated that a horizontal hydraulic conductivity of 0.03 ft/d probably is typical of rocks in the area (INTERA Environmental 

Consultants, Inc., 1984, p. 82). However, penneameter tests of 

core samples from a borehole at Gibson Dome indicated horizontal hydraulic-conductivity values ranging from 0.000068 to 

0.0042 ft/d, and drill-stem tests of the lower Paleozoic rocks at 

Gibson Dome indicated horizontal hydraulic-conductivity 

values ranging from 0.0034 to 0.068 ft/d (Thackston and others, 

1984, p. 67).

The problem of the test volume in determining hydrologic 

properties was addressed by Dagan (1986) from a statistical 

viewpoint. Dagan considered three scales: the pore scale, the 

local scale, and the regional scale. The pore scale, which can be 

assessed by laboratory measurements of core, is on the order of 

0.3-3 ft. The local scale, which can be addressed by single-well 

or multiple-well aquifer tests, is on the order of the aquifer thickness in the horizontal and vertical planes (typically 30-300 ft). 

The regional scale (measured in miles in the horizontal plane) is 

much larger than the aquifer thickness and presumably would be 

conducive to resolution by numerical modeling.
METHODS OF ANALYSIS B7

Increasing values of permeability and hydraulic conductivity with increasing scale are best understood in terms of the 

degree of heterogeneity introduced as the volume of rock under 

consideration expands. At the pore scale, permeability and 

hydraulic conductivity depend mainly on the void spaces 

(pores) between rock grains and, in less than perfect samples, 

cracks and vugs. At the local scale, permeability measurements 

take into account large openings, such as joints, fault planes, 

and solution channels. At the regional scale, lateral variations in 

lithology also can affect results.

In discussing permeability throughout this report, efforts 

were made to avoid mixing pore-scale and local-scale values 

(regional-scale values generally were not available) in the same 

context. For example, in preparing maps or plots of permeability distribution for a hydrogeologic unit, pore-scale values 

first were converted to local-scale values, or vice versa, 

depending on the purpose of the illustration. (An analogous 

situation would be to prepare a potentiometric-surface map 

using only heads from the same interval within a lithologically 

heterogeneous aquifer). Although the reason for the scale

dependence of permeability may not have been ascertainable 

for all data used in this report, following Dagan (1986), 

laboratory-determined permeability and equivalent laboratorydetermined permeability (permeability estimated from porosity, 

for example) in this report are called pore-scale permeability. 

Field-determined permeability and equivalent field-determined 

permeability (permeability estimated from laboratorydetermined permeability or hydraulic conductivity) are called 

local-scale permeability.

Pore-scale permeability usually is determined with a 

permeameter, a device that measures the rate at which water or 

gas (typically, nitrogen or air) moves through a sample of rock 

(Freeze and Cherry, 1979, p. 335-337). Assumptions inherent 

in the methods used to determine pore-scale permeability and 

other hydrologic properties studied during the UCRB-RASA 

are summarized in table 2. For this study, 7,659 measurements 

of pore-scale permeability based on plugs of borehole core 

(compiled by Petroleum Information Corp., unpub. data) and 

6 measurements based on outcrop samples (reported by Hood, 

1976, and Hood and Patterson, 1984) were available.

TABLE 2. Types of aquifer tests and methods of analysis used in determining hydrologic properties of Paleozoic

rocks in the Upper Colorado River Basin

[T, transmissivity; S, storativity; K, hydraulic conductivity; k, intrinsic permeability; N/A, not applicable]

Category yp 

6 J of test

I Pumping

well

Pumping

well

Pumping

well

Pumping

well

Pumping

well

II Flowing

well

Flowing

well

Drill

stem

III Pressure

injection

Slug

injection

IV Permeameter

Permeameter

Assumed test conditions 1

Constant

Discharge

Discharge

Discharge

Discharge

Discharge

Head

Head

Discharge

Head,

discharge

Fluid

volume

Fluid

volume

Discharge,

head

Changing

Head

Head

Head

Head

Head

Discharge

Discharge

Head

Not

relevant

Head

Head

Not

relevant

Confining 

layer

Nonleaky

Nonleaky

Nonleaky

Leaky

Leaky

Nonleaky

Leaky

Nonleaky

Not

relevant

Not

relevant

Not

relevant

Not

relevant

Test 

phase

Production

Recovery

Production,

recovery

Production

Production,

recovery

Production,

recovery

Production

Recovery

Entire

Entire

Entire

Entire

Where 

data 

obtained

Production

well

Production

well

Observation

well

Production

well

Observation

well

Production

well

Production

well

Production

well

Injection

well

Injection

well

Rock

samples

Rock

samples

Methods of analysis

Type-curve 

matching

Theis

(1935)

Theis

(1935)

Theis

(1935)

Hantush

(1960)

Hantush

(1960)

Jacob and

Lohman

(1952)

Hantush

(1959)

N/A

N/A

Cooper

and others

(1967)

N/A

N/A

Straight-line

Cooper and Jacob

(1946)

Theis (1935).

Cooper and

Jacob (1946)

Cooper and Jacob

(1946)

N/A

N/A

Jacob and Lohman

(1952)

N/A

Horner(1951)

N/A

Ferris and Knowles

(1963)

N/A

N/A

Direct solution 

of an equation

Lohman (1979)

N/A

N/A

N/A

N/A

N/A

N/A

Earlougher(1977);

Geldon(1989c)

Bureau of

Reclamation

(1974)

N/A

Freeze and

Cherry (1979)

Freeze and

Cherry (1979)

Hydrologic 

properties

T

T

T. S

T

T, S

T

T

k

K

T

k

k

'All analytical methods for categories I and II assume infinitesimal well diameter and instantaneous release from storage.
REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

Additional pore-scale permeability values were obtained 

from equations relating permeameter-determined permeability 

to porosity, as was done by Bredehoeft (1964) in a study of 

porosity and permeability in the Tensleep Sandstone in the 

Bighorn Basin, Wyo. (location shown on pi. 1). Porosity was 

plotted against permeameter-determined permeability by 

hydrogeologic unit and rock type for 7,516 samples. This 

resulted in the development of nine equations for estimating 

pore-scale permeability from porosity (table 3). These nine 

equations update versions appearing in an article by Geldon 

(1985b), based on an improved understanding of the stratigraphy and a more accurate identification of the sampled intervals. Regardless of hydrogeologic unit, the results of this study 

indicate that there generally is vague to excellent correlation 

between porosity and pore-scale permeability in sandstone, but 

no correlation to little correlation between these properties in 

carbonate rocks. As discussed later in this report, this observation is interpreted to indicate that pore-scale permeability in 

sandstone is related mainly to grain size, sorting, and degree of 

cementation, whereas pore-scale permeability in carbonate 

rocks depends mostly on fractures and vugs.

Drill-stem-test results from reports by Woodward-Clyde 

Consultants (1982) and Teller and Chafin (1986) and from 

unpublished files compiled by Petroleum Information

Corporation furnished 405 values of local-scale permeability. 

Most of these values (258) were determined by the method of 

Horner (1951). As described by Bredehoeft (1965), this method 

involves plotting pressure in the well bore during a shut-in 

period against log [(t + Af)/A?]. Permeability is calculated from 

the straight-line portion of the plot with the following equation:

162.6 qv (1)

h(p -p )

O "W

where

k = permeability, in millidarcies; 

q = discharge rate, in barrels/day; 

pw = well-bore pressure, in pounds per square inch; 

p0 - undisturbed formation pressure, in pounds per square

inch;

h = thickness of the tested interval, in feet; 

v = viscosity, in centipoise. 

t = flow period, in minutes; and 

A? = shut-in period, in minutes.

All of the variables necessary to solve equation 1 for permeability, except viscosity and discharge, generally are measured 

directly. Viscosity usually is estimated from the temperature of

TABLE 3. Equations relating porosity to pore-scale permeability for hydrogeologic units composed 

of Paleozoic rocks in the Upper Colorado Basin

[<, less than; p. porosity]

0

1ta

 o 

fi

"fi

o

c

ta

U

'3

3

SUJ

^3

o o

<3

o

Hydrogeologic unit

Park City-State Bridge zone

Weber-De Chelly zone

Cutler-Maroon zone

Paradox-Eagle Valley subunit

Belden-Molas subunit

Rock type

Sandstone

Dolomite

Limestone

Sandstone

Sandstone

Limestone

Sandstone

Dolomite

Limestone

Shale

Anhydrite

Dolomite

Limestone

Equation1

Jt =

k =

k =

k =

k =

k 

k =

0.022 £-°-41P

0.0091 <?°-46p

0.017ea46P

0.017ea35P

0.035 e°-25P

0.019<?037P

0.017eL2P

Correlation coefficient 

(R)

0.67

.83

<.60

.87

.66

<.60

.61

<.60

.62

<.60

<.60

.95

<.60

Number of 

observations

30

521

76

2.636

292

195

37

722

1,649

41

15

7

10

U

Darwin-Humbug zone 

Redwall-Leadville zone

Sandstone 

Dolomite

Dolomite 

Limestone

<.60 

<.60 

<.60 

<.60

19

9

435

513

Elbert-Parting confining unit 

Bighorn aquifer

Sandstone 

Dolomite

Dolomite

k = 0.010 <?°- 69P 

k = 0.0032 <?°-74P

.77

<.60

.81

125

89

45

*No equation shown if the regression coefficient was less than 0.60.
METHODS OF ANALYSIS B9

the water in the test interval. During this investigation, viscosity 

usually was estimated from equations given by Teller and 

Chafin (1986, p. 9). These equations are:

= 1.93 - [0.818 xLog(0.556xTB -22.8)],

Tn - 50° to 120° ts

u = 0.935 - [0.367 x Log(0.556 x TR - 57.8)], 

D = 120° to 425°

(2)

(3)

where

H - dynamic viscosity, in centipoise; and 

TB = temperature in the test interval, in degrees 

Fahrenheit.

If the temperature in the test interval was not measured, it was 

estimated from the thermal gradient in the borehole and the testinterval depth. If the thermal gradient was unknown, it was estimated from figure 2, a map of thermal gradients prepared from 

temperatures recorded during drill-stem tests (Woodard-Clyde 

Consultants, 1982; Teller and Chafin, 1986; Petroleum 

Information Corporation, unpublished) and from published 

thermal-gradient information in reports by American 

Association of Petroleum Geologists and U.S. Geological 

Survey (1976), Barren and Pearl (1977), Law and others (1980), 

MacMillan (1980), Law and Smith (1983), Bostick and 

Freeman (1984), and Nuccio and Johnson (1984).

Drill-stem-test discharges were calculated by the following 

equation:

q = 20.5 R/t (4)

where

q = the discharge rate, in barrels/day (to obtain the 

discharge rate in gallons per minute, a constant of 

0.60 was used instead of 20.5); 

R = length of fluid-filled drill stem, in feet; and 

t = the flow period, in minutes.

The constant in equation 4, 20.5, assumes a standard drill-stem 

diameter of 3.83 in (Bredehoeft, 1965) and is equal to 0.01422 

barrels per foot x 1,440 minutes per day; the constant, 0.60, is 

based on the assumption of 42 gallons per barrel. In order to use 

the drill-stem test to calculate permeability, it was decided arbitrarily in this investigation that the recovered fluid had to be at 

least 75 percent water or some form of water, such as muddy, 

salty, oil-cut, or gas-cut water.

Where data were insufficient for a Horner plot, summary 

information for the test was used to estimate local-scale permeability. One hundred forty-seven values of local-scale permeability were obtained from summary data by using two different 

methods.

If the information from two flow periods and two shut-in 

periods was available, local-scale permeability was determined 

by the following equation:

k =

162.6 qv + Af.)]

(5)

hi p p 

( w l W 2

where

fj = the initial flow period, in minutes; 

?2 = the final flow period, in minutes; 

Afj = the initial shut-in period, in minutes; 

Ar2 = the final shut-in period, in minutes; 

pw = the reported pressure during the initial shut-in period,

in pounds per square inch; and

pw = the reported pressure during the final shut-in period, 

in pounds per square inch; and all other variables 

are the same as in equation I .

Equation 5 was derived from equation 1 by substitution of 

variables for each flow period and shut-in period separately into 

the original equation, subtraction to eliminate p from the equation, rearrangement of variables, and solution of simultaneous 

equations. An evaluation of equation 5 using data from actual 

drill-stem tests indicated that the equation gives reasonable 

results only if the following criteria are met: 

1 . The initial flow period should be at least 3 to 5 minutes long;

2. The second flow period should not differ from the first by 

more than 150 minutes;

3. The ratio of the initial shut-in period to flow period must be 

significantly different from the ratio of the final shut-in 

period to flow period; and

4. The initial shut-in pressure must exceed the final shut-in

pressure.

If the summary information for a drill-stem test failed to meet 

these criteria, the test was not used to calculate permeability by 

this "two-flow-period" method.

Drill-stem tests with one flow period or an initial flow 

period of less than 3 to 5 minutes and decreasing shut-in pressure could be analyzed from summary information using an 

equation given by Earlougher (1977):

162.6

h\p

V H'! W,

where

a formation constant ranging from 0.99 to 1 .06 ((3 can 

be ignored if unknown because it approximately 

equals 1); and all other variables are the same as in 

previous equations.
BIO REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

 2.0 Line of equal thermal gradient 

Interval 0.2 degrees Fahrenheit per 

100 feet

 Borehole with measured thermal 

gradient

National Oceanic and Atmospheric 

Administration weather station 

Number is average annual air 

temperature at station in degrees 

Fahrenheit. If fewer than two 

temperatures were recorded in a 

borehole, the gradient was calculated 

as the difference between the 

borehole temperature and the 

ambient average annual air 

temperature divided by the depth at 

which the temperature was recorded

AREA EXCLUDED 

FROM STUDY

25

I

75 100 MILES

25 50 75 TOO KILOMETERS

FIGURE 2. Generalized distribution of thermal gradients in deep boreholes in the Upper Colorado River Basin.
METHODS OF ANALYSIS Bll

In addition to local-scale permeability values obtained 

from drill-stem tests, 182 values of local-scale permeability 

were estimated from pore-scale permeability on the basis of 

equations developed during this study. These equations were 

determined from paired values of core and drill-stem test 

permeability values obtained from 22 stratigraphic intervals 

penetrated by either a single borehole or two boreholes no 

more than 5 mi apart (table 4). If the data from two boreholes 

were used, assurance that the data came from the same stratigraphic interval was based on the lithology of the formation 

and the apparent dip of stratigraphic markers between the 

boreholes. For each of the stratigraphic intervals, the drillstem test permeability was plotted against the maximum value 

of core permeability and the arithmetic and geometric means 

of the core permeability values independent of rock type and 

by rock type. The largest correlation coefficients resulted 

when rock type was considered. For sandstone, the drill-stem 

test permeability was found to be related most closely to the 

geometric mean of the core permeability values (fig. 3A). For 

carbonate rocks, the drill-stem test permeability was found to 

be related most closely to the arithmetic mean of the core 

permeability values (fig. 3B).

On the basis of figure 3, local-scale permeability can be estimated from pore-scale permeability by the following equations:

:, = 1.4 k 1 s

0.65

k, = 3.5 k 1 c

0.80

(7)

(8)

where

A*j = local-scale permeability, in millidarcies, 

ks = pore-scale permeability for sandstone, in millidarcies; and 

kc = pore-scale permeability for carbonate rocks, in

millidarcies.

Because equations 7 and 8 are based on small numbers of 

paired values, their use is dependent on required precision. They 

were considered sufficiently reliable where used in the UCRBRASA.

HYDRAULIC CONDUCTIVITY

Hydraulic-conductivity values used in this study were determined either by calculation from permeability values, by analysis of pressure-injection tests, or by calculation from 

transmissivity values. Transmissivity was determined either by 

constant rate, airlift, or step-drawdown pumping tests, bailing 

tests, slug tests, or flowing-well tests.

Five hundred eighty-eight values of hydraulic conductivity were calculated from permeability data. The permeability data consisted of 405 determinations from drill-stem

tests, 135 estimates from laboratory-determined (pore-scale) 

permeability, and 47 estimates from porosity determined 

from borehole geophysical logs. One value of hydraulic 

conductivity was estimated from pressure-recovery data 

obtained during a flowing-well test of the Leadville 

Limestone near McCoy, Colo. Hydraulic conductivity was 

calculated from the flowing-well test after first estimating 

local-scale permeability using equation 5 (the two-flow 

period equation).

In this study, hydraulic conductivity was calculated from 

permeability by one of three equations, depending on the 

amount of information available for determining properties of 

the recovered fluid. If the temperature of the fluid was known, 

then viscosity could be estimated using equation 2 or 3. If the 

dissolved-solids concentration also was known, then hydraulic 

conductivity was calculated from the following equation 

(Weiss, 1982):

k x 1 +

K =

77)5/1,000 

300

365 v

(9)

where

K - hydraulic conductivity, in feet per day; 

k = local-scale permeability, in millidarcies; 

v = viscosity, in centipoise; and

TDS = dissolved-solids concentration, in milligrams 

per liter.

If only the temperature of the fluid was known or could be estimated, the following equation was used:

K = k/365v (10)

where all variables are the same as in equation 9. If neither the 

temperature nor the dissolved-solids concentration was known, 

the following equation (modified from Teller and Chafin, 1986, 

p. 9) was used:

K = Jt/410.5 (11)

where

K = hydraulic conductivity at 60°F, in feet per day; 

and k is the same as in equation 9.

The factor, 410.5, is based on the fact that rock with a 

permeability of 1 millidarcy can transmit water at a rate of 

0.00243 ft3/d/ft2 at 60°F.

Hydraulic conductivity was calculated directly from the 

results of 210 pressure-injection tests in 16 wells at 6 damsites. 

The data from these tests, and, in most cases, the calculated 

hydraulic-conductivity values were made available by the
B12 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

TABLE 4. Comparison of closely obtained drill-stem test and core-permeability values for Paleozoic rocks in the Upper Colorado River Basin 

[Compared sites are no more than 5 miles apart; equivalent intervals identified by lithology and apparent dip of formation tops; dashes indicate not applicable]

Geologic 

unit

Cutler

Formation

Tensleep

Formation

Weber

Sandstone

Weber

Sandstone

Weber

Sandstone

Hermosa

Formation

Hermosa

Formation

Hermosa

Formation

Hermosa

Formation

Hermosa

Formation

Hermosa

Formation

Hermosa

Formation

Hermosa

Formation

Hermosa

Formation

Hermosa

Formation

Hermosa

Formation

Hermosa

Formation

Hermosa

Formation

Redwall

Limestone

Redwall

Limestone

Elbert

Formation

Elbert

Formation

Drill-stem 

test site

NMB38-15-21bcb

SB26-89-06ca

SB04-103-32cc

SLA03-25-28bb

SLD05-22-23cba

GA41-28-llca

GA41-30-16cdb

NMB33.5-20-16cba

NMB33.5-20-25cb

NMB33.5-20-25cb

SLD38-25-05dda

SLD40-21-12dd

SLD40-21-14aaa

SLD40-23-14caa

SLD40-24-07bdc

SLD40-25-23cb

SLD41-23-12dd

SLD41-25-26cc

SLD23-17-16da

GA41-28-03bd

GA37-29-35bbc

GA41-28-03bd

Interval 

(in feet below 

land surface)

Top

3,628

6,418

1.140

11,675

4,047

4,876

5,000

5,843

5.800

5,850

5,392

5,623

5.170

5,627

6,165

5,931

5,557

5,364

8,682

5,569

3,415

5.945

Bottom

3.655

6,472

1,180

11,885

4,169

5,040

5,051

5.863

5,850

5,902

5,452

5.751

5.251

5,700

6,240

5,953

5,606

5.394

8,814

5.693

3,483

6,032

Drillstem test 

permeability 

(in millidarcies )

1.4

.13

1.7

.14

17

13

1.6

.44

1.1

4.0

1.2

.16

17

30

.70

28

200

14

32

13

6.0

1.5

Core

site

NMB38-15-21bcb

SB26-90-01cda

SB03-104-12bba

SLA03-24-22bda

SLD05-22-23cba

GA41-28-03cab

GA41-30-21cab

NMB33.5-20-16cba

NMB33.5-20-22bc

NMB33.5-20-21dac

SLD37-25-32cad

SLD40-21-14aaa

SLD40-21-14aaa

SLD40-23-13bdd

SLD40-24-22aba

SLD40-25-26bbb

SLD4 1-23-1 2aaa

SLD41-25-32bbd

SLD23-17-17ada

GA41-28-04dab

GA37-29-35bbc

GA41-28-04dab

Interval . . , 

. ., , , Arithmetic (in feet below 

mean of land surface )

values

Top

3,629

6,338

9,303

9,044

4,053

4,775

5,074

5,843

5.694

5.721

5,665

5,370

5.231

5.696

5,893

5,953

5,592

5,347

8.693

5,702

3,442

5,974

within 

Bottom . . , interval

3,651 7.9

6,391 4.7

9,343 2.3

9,264 .41

4.166 68

4.787 23

5,117 .18

5,863 .62

5,732 2.1

5.771 9.8

5,675 .17

5,414 .11

5.250 13

5.751 3.1

5.919 .06

5,979 9.3

5,642 12

5,377 1.2

8,824 6.3

5,720 3.0

3.466 8.9

5,988 23

Geometric , , . 

. Maximum 

mean of . , value Lithology values , . ,, . within of interval within interval interval

3.2 40 Arkosic

sandstone

.52 51 Quartz

sandstone

.41 22 Quartz

sandstone

.022 9.0 Quartz

sandstone

31 380 Quartz

sandstone

115 Dolomite

1.0 Limestone

4.9 Limestone

and

dolomite

45 Limestone

and

dolomite

60 Mostly

dolomite

.38 Anhydrite

and shaly

dolomite

1.7 Limestone

and

dolomite

120 Limestone

and

dolomite

47 Limestone

.43 Limestone

60 Limestone

146 Mostly

limestone

27 Limestone

and

anhydritic

limestone

73 Dolomite

13 Cherty

dolomite

1.1 24 Dolomitic

and

quartzitic

sandstone

1.0 179 Sandstone
METHODS OF ANALYSIS B13

100

A SANDSTONE

10

0.1

Correlation coefficient = 0.80

I I

0.01

200

0.01

0.1 1 10 100 

GEOMETRIC MEAN OF CORE PERMEABILITY VALUES, IN MILLIDARCIES

1,000

Correlation coefficient = 0.78

0.1 1 10 100 

ARITHMETIC MEAN OF CORE PERMEABILITY VALUES, IN MILLIDARCIES

1,000

FIGURE 3. Relations for sandstone and carbonate rocks between permeability determined from cores and permeability 

determined from drill-stem tests at closely spaced sites in the Upper Colorado River Basin.
B14 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

Bureau of Reclamation (Salt Lake City and Denver offices, 

written commun., 1983-1985). The methods and analytical 

procedures used in the tests are described by Bureau of 

Reclamation (1981b, p. 249-266). The relevant equation is:

K = 30.661n(L/r) 

LH

where

K = hydraulic conductivity, in feet per day; 

Q - discharge, in gallons per minute; 

L = test interval, in feet; 

r = well radius, in feet; and 

H = head, in feet.

Hydraulic conductivity was calculated from 63 pumping, 

bailing, airlift, injection, and slug tests by dividing the transmissivity value obtained from the test by the test-interval thickness 

(methods of determining transmissivity from these tests are 

described in the next section). In a flowing-well test of the 

Leadville Limestone at Glenwood Springs, Colo., the hydraulic 

conductivity was calculated by dividing the thickness of the 

Redwall-Leadville zone, rather than the thickness open to the 

well (28 percent of the zone), because water is believed to be 

transmitted to the well used in the test by faults and fractures 

that permeate the entire Redwall-Leadville zone.

Regional distributions of unit-averaged hydraulic conductivity in hydrogeologic units were determined by two methods. 

For hydrogeologic units with sufficient data, values of hydraulic 

conductivity for intervals representative of the lithology of the 

entire hydrogeologic unit at the sites where these values were 

obtained were contoured. For hydrogeologic units with sparse 

data, unit-averaged hydraulic conductivity was determined at 

grid centers on a 10-mi x 10-mi grid from the thickness of each 

rock type in the hydrogeologic unit at the grid center and the 

median values of hydraulic conductivity for the individual rock 

types in the hydrogeologic unit. These estimated values were 

then contoured.

TRANSMISSIVITY

Very few determinations of transmissivity by aquifer tests 

were found during an extensive search of published reports and 

files of governmental agencies. For this reason, aquifer tests of 

formations in the UCRB from areas beyond the boundaries of 

the UCRB were used to support hydrogeologic interpretations. 

Accordingly, 14 flowing-well tests of the Flathead Sandstone, 

Madison Limestone, and Tensleep Sandstone in the Bighorn 

Basin, about 115 mi northeast of the crest of the Wind River 

Mountains (Cooley, 1985), and 2 pumping tests of the Coconino 

Sandstone in the Lower Colorado River Basin, 80 to 100 mi 

south of the UCRB (Akers, 1964; Cooley and others. 1969), 

were incorporated into the database.

Within the UCRB, only 15 constant-rate pumping tests were 

found. These included one test in the Cutler Group and upper 

member of the Hermosa Formation (Thackston and others, 

1984, p. 21-31), two tests in the Weber Sandstone (Hood, 1976, 

p. 53-54; Sumsion, 1976, p. 51-59), six tests in the De Chelly 

Sandstone (Cooley and others, 1969), and six tests in disturbed 

blocks (caprock) of the Paradox Member of the Hermosa 

Formation (Wollitz and others, 1982). The latter tests were 

given little weight in interpretation of the hydrologic properties 

of the Paradox Member because the data curves were not 

convincingly analyzable by the method used, and the transmissivity of the caprock probably differs from that of the rock in 

place. The 15 pumping tests were analyzed by either the Theis 

(1935) nonequilibrium solution, the Theis (1935) recovery 

method, or the Cooper and Jacob (1946) modification of the 

Theis nonequilibrium solution. Test procedures are described 

by Lohman (1979). The equations for the Theis nonequilibrium 

solution are:

T = -2-

4ns

(13)

where

T = transmissivity, in feet squared per day; 

Q = discharge, in cubic feet per day; 

s = drawdown, in feet, at the type-curve match point; and 

= the nonleaky well function of u, at the type-curve 

match point.

/ S 

477

(14)

where

r = distance from the center of the well, in feet;

S = storativity, dimensionless;

t = time since flow started, in days; and

T is the same as in equation 13.

The equation for the Theis recovery and Cooper-Jacob 

methods, assuming u, < 0.01, is:

(15)

As

where

T = transmissivity, in feet squared per day; 

Q = discharge, in gallons per minute; and 

sj = change in drawdown, residual drawdown, 

recovery, in feet, over 1 log cycle of time.

or
METHODS OF ANALYSIS B15

An "airlift" pumping test of the Cutler Group and upper 

member of the Hermosa Formation (Woodward-Clyde 

Consultants, 1982; Thackston and others, 1984) provided one of 

only two composite transmissivity values for the entire thickness of the Cutler-Maroon zone of the Canyonlands aquifer. The 

test was done by displacing water from a well using compressed 

air and monitoring the recovery of head (pressure). Although 

not specifically stated, the recovery data presumably were 

analyzed using equation 15.

The data from an aborted step-drawdown pumping test of 

the Leadville Limestone at Ouray, Colo. (fig. 4), that was done 

in 1988 were analyzed by separating the total drawdown into 

components related to individual increments of discharge 

added during the test. For example, from 1 to 5 minutes, with 

the pump discharging at a rate of 49.6 gal/min, total drawdown 

remained constant at 4.44 ft. Therefore, it was assumed that 

the drawdown related to the first increment of discharge 

remained constant at 4.44 ft throughout the test. At 6 minutes, 

the discharge was increased by 49.7 gal/min, and the 

drawdown increased to 10.22 ft. Therefore, the drawdown

FIGURE 4. Uncompahgre River at Ouray. Colorado, near site of 

well OX-3 (NMB44-07-31cbd3 ). Cliffs above the river are 

Leadville Limestone of Mississippian age.

attributed to the second increment of discharge (49.7 gal/min) 

at 6 minutes was 10.22 ft - 4.44 ft = 5.78 ft. Values of drawdown attributed to the second discharge increment from 6 to 

12 minutes were plotted against the log of time, and a trend 

was extrapolated for further calculations. At 14 minutes, the 

discharge was increased by 51.7 gal/min, and the total drawdown was 16.00 ft. The drawdown attributable to the second 

increment of discharge at 14 minutes was determined from the 

extrapolated trend of drawdown with time to be 11.1 ft. Thus, 

the drawdown attributable to the third increment of discharge 

at 14 minutes was 16.00 ft - 4.44 ft -11.1 ft = 0.46 ft. Continuation of this process for all subsequent measurements of 

drawdown during the test allowed calculation of the drawdown with time attributable to each of the five increments of 

discharge added during the pumping test. The semilog plots of 

drawdown against time for all but the first discharge increment 

(fig. 5) were analyzed using equation 15, and the separate 

transmissivity values determined were averaged to obtain a 

solution for the test (discussed in the section on the RedwallLeadville zone).

Two bailing tests in the Belden and Maroon Formations 

were analyzed by applying equation 15 to residual drawdown 

data from these tests; another bailing test in the Belden 

Formation was analyzed using the method of Skibitzke (1958). 

The data for these tests, all of which were done in 1963 during 

site investigation for Ruedi Dam near Meredith, Colo. (location 

shown on pi. 1), were provided by the Bureau of Reclamation 

(written commun., 1985). The Skibitzke (1958) equation is:

T -

V

4ns't

(16)

where

T = transmissivity, in feet squared per day; 

V = volume bailed, in cubic feet; 

s' = residual drawdown, in feet; and 

/ = time since bailing stopped, in days.

An "airlift" test of the Leadville Limestone at Ouray was 

done on July 15, 1987. All of the water in a 320-ft-deep, flowing 

well was blown out using compressed air during a 5-minute 

period. Recovery of the water level in the well then was monitored. Since the water in the well was removed essentially 

instantaneously, the test could be analyzed as a slug test using 

the method of Cooper and others (1967) and type curves 

prepared by Reed (1980).

Three slug tests done in salt beds of the Paradox Member of 

the Hermosa Formation by Rush and others (1980) provided 

additional transmissivity data. These tests also were analyzed 

by the method of Cooper and others (1967).

Thackston and others (1984) described four injection tests 

of the Redwall Limestone at a site on the Monument upwarp. 

Transmissivity and hydraulic conductivity were determined
B16 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN. EXCLUDING THE SAN JUAN BASIN

10

15

I

20

25

30

35

TTT

Extrapolated drawdown trend 

Drawdown S2 due to discharge increment AO 2 

Drawdown S 3 due to discharge increment Ada 

Drawdown S 4 due to discharge increment AQ 4 

Drawdown SB due to discharge increment AQs

I I \

10 100 

TIME SINCE DISCHARGE INCREMENT STARTED, IN MINUTES

1,000

FIGURE 5. Drawdown in well OX-3 (NMB44-07-31cbd3 ) at Ouray, Colorado, during aquifer test of April 25, 1988. (Drawdown during the 

first increment of discharge did not change with time and is not shown. The drawdown during the fifth increment of discharge apparently was 

affected by a barrier boundary about 32 minutes after this increment began. Data from the test were provided by David Vince, City of Ouray, 

written commun., 1988.)

from these tests using equations 1 and 15. For each property, the 

calculated values from the four tests were so similar that the 

average was considered to be a reasonably good indication of 

the property being determined. These average values were 

added to the database.

Two flowing-well tests of the Leadville Limestone were 

analyzed. One of these, at McCoy, Colo., was analyzed using 

equation 5 to obtain local-scale permeability. Permeability was 

converted to hydraulic conductivity by equation 11 and to transmissivity by multiplying the hydraulic conductivity by the testinterval thickness.

A flowing-well test of the Leadville Limestone at Glenwood 

Springs, Colo. (Geldon, 1989c), was made during this study and 

analyzed using an extensive monitoring network. Changes in 

head in the production well at Glenwood Springs were observed 

directly by means of a standpipe attached to the well. Discharge 

was measured by the orifice-plate method (Bureau of

Reclamation, 1981b, p. 233-242). Four observation wells and 

three springs were monitored at Glenwood Springs in addition 

to the production well. A recording barometer was set up near 

the site to adjust recorded water levels for changes in 

atmospheric pressure. Test data from the Glenwood Springs test 

were analyzed by the straight-line method of Jacob and Lohman 

(1952) and the type-curve matching method of Hantush (1960). 

The equation for the Jacob-Lohman method is:

= 0.183x 1,440 (17)

where

T = transmissivity, in feet squared per day; and 

A (s/Q)d = change in specific discharge over 1 log cycle of 

time, in feet per gallon per minute.
METHODS OF ANALYSIS B17

The equation for the Hantush (1960) type-curve matching 

method is:

192.5 QH(\i)

4ns

(18)

where

T = transmissivity, in feet squared per day; 

Q = discharge, in gallons per minute; 

s - drawdown or recovery at type-curve match point; in

feet; and

//(u) = the leaky aquifer with storage in the confining bed 

well function of u at the type-curve match point; 

and 

).i = the same as in equation 14.

Thirty-eight specific-capacity (pumping, bailing, and airlift) 

tests on file with the Colorado Department of Natural 

Resources, Division of Water Resources, Office of the State 

Engineer, provided the remaining transmissivity values. Transmissivity was estimated from specific capacity using either of 

two equations. If the well radius and pumping duration were 

known, then the following equation from Lohman (1979, p. 52) 

was used:

Q (19)

2.3 Log 2.25 Tt

where

Q = discharge, in cubic feet per day; 

sw - drawdown, in feet; 

T - transmissivity, in feet squared per day; 

t = pumping time, in days; 

rw - radius of well, in feet; and

S = storativity, dimensionless, and assumed equal to the 

test interval thickness multiplied by 0.000001.

If only the discharge and drawdown were known, then transmissivity was estimated using the following equation from Driscoll 

(1986, p. 1021):

2,000 Q (20)

where all variables are the same as in equation 18, except that T 

is in gallons per day per foot.

Regional distributions of composite transmissivity in the 

hydrogeologic units were determined for each unit by 

contouring grid-center values on a 10-mi x 10-mi grid. If a 

measured or estimated value of transmissivity representative of 

the entire thickness of a hydrogeologic unit was near a grid

center, it was used for the grid-center value. Otherwise, the gridcenter value was obtained by multiplying the unit-averaged 

hydraulic conductivity by the thickness of the hydrogeologic 

unit at the grid center. Contouring of the grid-center values was 

guided by the structural setting.

STORATIVITY

Conventionally, storativity is calculated from observationwell drawdown or recovery data in a pumping or flowing-well 

test (see Lohman, 1979). Only the flowing-well test of the 

Leadville Limestone at Glenwood Springs done during this 

study provided data sufficient for the calculation of storativity. 

The equation used was:

S =

_ 4Tt\i

1,440/

where 

S 

T

t

= storativity, dimensionless;

= transmissivity, in feet squared per day;

= time at type-curve match point, in minutes; 

r = distance of observation well from production well,

in feet; and 

u = a type-curve match point.

Specific storage equals the storativity divided by thickness. 

The regional range in storativity for the Redwall-Leadville zone 

of the Madison aquifer was estimated from specific storage in 

the Glenwood Springs area and the range in thickness of the 

Redwall-Leadville zone in the UCRB. Specific storage in the 

Glenwood Springs area was calculated from the storativity of 

the Leadville Limestone determined during the flowing-well 

test at Glenwood Springs and the thickness of the RedwallLeadville zone at Glenwood Springs.

Storativity also can be estimated from porosity and known 

or assumed physical constants of water and rock, as described 

by Lohman (1979, p. 9):

S =

+ *

(22)

where 

S 

<D

Y

b

P

= storativity, dimensionless;

= porosity, in percent;

= specific weight of water, which equals 0.036 pounds

per cubic inch; 

= aquifer thickness, in feet; 

= compressibility of water, which equals 0.0000033

square inch per pound; and 

= compressibility of the rock skeleton, in square inches

per pound.
B18 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

The regional distribution of storativity in the WeberDe Chelly zone of the Canyonlands aquifer was estimated using 

equation 22, values of porosity and thickness determined on a 

10-mi x 10-mi grid, and the compressibility of the Cretaceous 

Fox Hills Sandstone (0.0000011 in2/lb), as reported by Taylor 

(1968).

YIELD

Yield values reported in this study, unless otherwise noted, 

are artesian flows into or from wells or from springs. The well 

flows include discharges measured at the surface and discharges 

from specific horizons recorded during drilling or aquifer tests. 

Much of the yield data was calculated from the volume of fluid 

recovered during drill-stem tests (using equation 4). If more 

than one flowing interval was penetrated in a borehole or in 

closely spaced boreholes, the largest yield was used in characterizing the hydrogeologic unit in the area where the data were 

obtained. More than 800 yield values were available for 

interpretation.

Maps showing regionally distributed yields indicate the 

yield to be expected from the most productive horizon in a 

hydrogeologic unit under artesian (natural flow) conditions. 

Larger yields might occur if more than one producing horizon 

were penetrated by a well. Larger yields also could be obtained 

by pumping at a rate exceeding the natural flow rate (which 

would cause the water level in the well to be lowered). Smaller 

yields might occur if a well did not penetrate the most productive horizon or penetrated only a fraction of the thickness of this 

horizon.

For each hydrogeologic unit, determination of the probability of obtaining a certain yield was biased not only by the 

method of selecting data for this study but also by selectiveness 

in the original yield determinations. First, only wells drilled for 

a water supply that produced usable quantities of water were 

included in the database. Second, only drill-stem tests that 

produced enough water to calculate a discharge were included 

in the database. Third, drill-stem tests preferentially were 

conducted in intervals with a potential for petroleum production; less permeable intervals routinely were not tested, and 

intervals capable of yielding large quantities of water but not 

economically producible quantities of petroleum might have 

been overlooked. Finally, where springs were observed, generally only flows from the largest springs were measured or 

reported. Taking into account the nonrigorous sampling procedures, the true probability of a particular yield from a hydrogeologic unit at any site may differ from what is indicated by maps 

in this report.

PHYSICAL SETTING

In the UCRB, recurrent tectonic activity from Precambrian 

to Quaternary time, a period of more than 600 million years, has 

molded the terrain into extremely diverse landforms. Precipitation varies with the topography. The combination of topography 

and precipitation determines the course and discharge of the 

region's streams, and all of the above factors affect where water 

is added to or discharged from the Paleozoic rocks. Circulation 

of water in the Paleozoic rocks, therefore, not only is a function 

of the lithologic and hydrologic properties of these rocks but 

also is a reflection of the past and present effects of structural 

disturbance and erosion and the vagaries of a climate that is ever 

changing in both time and space.

TOPOGRAPHY

In the UCRB, the forces of running water, snow and rain, 

glaciers, and wind have carved a tremendous thickness of sedimentary, igneous, and metamorphic rocks into a jumbled landscape of mountains, plateaus, plains, and valleys. At the 

confluence of the Green and Colorado Rivers in Utah, the geologist and explorer, John Wesley Powell (1895) wrote,

Wherever we look there is but a wilderness of 

rocks deep gorges where the rivers are lost below 

cliffs and towers and pinnacles, ten thousand 

strangely carved forms in every direction, and beyond 

them mountains blending with the clouds.

The UCRB includes parts of four physiographic 

provinces the Middle Rocky Mountains, Wyoming Basin, 

Southern Rocky Mountains, and Colorado Plateaus (pi. 1). The 

land surface generally lies between altitudes of 5,000 to 8,000 ft 

(above the NGVD of 1929), but mountains rise as high as 

12,000 to 14,500 ft in altitude, and canyons 1,000 to 3,000 ft 

deep are common. The lowest point in the area, where the 

Colorado River leaves the basin at Lees Ferry, Ariz., is at an altitude of about 3,100 ft.

MIDDLE ROCKY MOUNTAINS

The Middle Rocky Mountains physiographic province in 

the UCRB and vicinity includes the Wind River Mountains, 

Gros Ventre Range, Overthrust Belt, Uinta Mountains, and 

Yampa Plateau (pi. 1). The northwest-trending Wind River 

Mountains (fig. 6A) rise abruptly above the Green River Basin 

to the southwest to altitudes in excess of 13,500 ft. Dissected 

erosional surfaces that cap the Wind River Mountains descend 

gradually northeastward to a series of cuestas and hogbacks 

flanking the Wind River Basin. The Gros Ventre Range is a 

northwest-trending but subdued extension of the Wind River 

Mountains. The Overthrust Belt consists of several north- to 

northwest-trending, steep-sided mountain ranges, ridges, and
PHYSICAL SETTING B19

intermontane valleys. Mountain crests exceed 11,000 ft in the 

northern part of the area but decrease in altitude southward; in 

the southern part of the area, mountains give way to ridges, 

which rise only 500 to 1,000 ft above adjacent lowlands. The 

Uinta Mountains and Yampa Plateau, together, form an unusual 

east-trending range. In the western Uinla Mountains, a sinuous 

arete with many spurs and pyramidal peaks 12,000 to 13,500 ft 

in altitude rises 1,000 to 2,000 ft above a broad-crested upland 

surface (fig. 6B). In the eastern Uinta Mountains, Browns Park

and narrow canyons of the Yampa and Green Rivers segment 

the range into four plateaus Cold Spring Mountain, Diamond 

Mountain, Douglas Mountain, and Blue Mountain. Plateau 

surfaces range from 8,000 to 9,700 ft in altitude.

WYOMING BASIN

The Wyoming Basin physiographic province in the UCRB 

and vicinity includes the Hoback, Green River, Great Divide, 

and Washakie Basins (collectively referred to as the greater

FIGURE 6. Landscapes of the Middle Rocky 

Mountains physiographic province: 

A. Wind River Mountains Square Top 

Mountain, composed of Archean gneiss, is 

reflected in Upper Green River Lake near 

the headwaters of the Green River north of 

Pinedale, Wyoming. B. Western Uinta 

Mountains Mount Agassiz, composed 

mostly of quartzite of the Proterozoic Uinta 

Mountain Group, towers above a meadow 

northeast of Kamas, Utah.

B
B20 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

Green River Basin); the Sand Wash and Hanna Basins; the 

Sweetwater Arch; and the Rock Springs and Rawlins Uplifts 

(pi. 1). All of the basins are characterized by undulating, sagecovered plains and badlands locally rising to low hills, buttes, 

mesas, and isolated mountains (fig. 1A). The floors of the basins 

generally lie at altitudes between 6,000 and 7,500 ft. However, 

cuestas bordering the Rock Springs and Rawlins Uplifts 

(fig. IB) and scattered buttes, such as the Oregon Buttes, crest

at altitudes between 7,500 and 8,500 ft, and in the Sand Wash 

Basin, the Williams Fork and Elkhead Mountains tower 2,000 

to 5,000 ft above adjacent lowlands.

SOUTHERN ROCKY MOUNTAINS

The Southern Rocky Mountains physiographic province in 

the UCRB and vicinity includes the Sierra Madre; Park, Gore, 

Rabbit Ears, Front, and Sawatch Ranges; Elk, West Elk, and

FIGURE 7. Landscapes of the Wyoming 

Basin physiographic province: A. Green 

River Basin Bluffs underlain by the 

Tertiary Wasatch and Green River 

Formations near La Barge, Wyoming. 

B. Rock Springs Uplift A cuesla of 

Cretaceous sandstone and shale flanks the 

eroded interior of the uplift known as the 

Baxter Basin, east of Rock Springs, 

Wyoming.

* * - *:»

B -mtZJ
PHYSICAL SETTING B21

San Juan Mountains; White River and Gunnison Plateaus; and 

the Middle Park and Eagle Basins (pi. 1). In the words of Frank 

Waters (quoted in Boddie and Boddie, 1984, p. 44),

With all their infinite variations, the mountains 

comprise not only heaving waves of forest, but jutting 

cliffs, abysmal gorges, and deep sunless canyons, 

vast open parks and tiny arctic meadows, small blue 

lakes, gushing warm geysers, mineral springs, cold

trout pools, lacy falls, heavy cataracts and great 

soggy marshes, cones and craters of extinct volcanoes, bristling hogbacks, rolling hills of sage and 

cedar, high groves of aspen, immense flat-topped 

mesas, solitary bluffs, and weirdly eroded buttes.

The Southern Rockies are the backbone of the continent, 

giving rise to four great rivers the Platte, Rio Grande, and 

Arkansas, which flow to the Atlantic, and the Colorado, which

FIGURE 8. Landscapes of the Southern 

Rocky Mountains physiographic province: 

A. Elk Mountains Two 14-thousand-foot 

peaks, Maroon Peak (14,156 feet) on the 

left and Pyramid Peak (14,018 feet) on the 

right, flank an alpine basin at the head of 

Maroon Creek, between Aspen and 

Crested Butte, Colorado. All of the rocks 

exposed belong to the Pennsylvanian and 

Permian Maroon Formation. The view is 

north from West Maroon Pass. B. Sawatch 

Range Mount Harvard (14,420 feet) and 

neighboring peaks composed of 

Proterozoic igneous and metamorphic 

rocks. View is southeast from Mount 

Belford(14,197feet).

B
B22 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

flows to the Pacific. Fifty-four peaks (twenty-nine in the 

UCRB) in the San Juan Mountains, Elk Mountains (fig. 8A), 

Gore Range, Sawatch Range (fig. &B), and Front Range exceed 

14,000 ft in altitude. Peaks of 12,000 to 13,000 ft in altitude are 

so common that many are unnamed.

Below the mountain summits, the land descends in a series 

of dissected erosional surfaces to high plateaus and intermontane basins. The White River Plateau is a broad, lava-capped 

highland that is bordered on the west by the sinuous Grand 

Hogback Monocline and transected near its southern end by 

Glcnwood Canyon, a 1,800-ft-deep gorge carved by the 

Colorado River. The Gunnison Plateau is a narrow upland 

underlain by Precambrian crystalline rocks into which the 

Gunnison River has incised a 2,000-ft-deep gorge known as the 

Black Canyon. Surfaces of the White River and Gunnison 

Plateaus generally lie at altitudes between 9,000 and 12,000 ft. 

In the Eagle Basin and Middle Park, streams meander through 

wide alluvial valleys bordered by terraces, low hills, and 

isolated mountains. Surface altitudes in these basins generally 

range from 5,000 to 8,000 ft.

COLORADO PLATEAUS

The Colorado Plateaus province is the largest and most 

topographically diverse region in the UCRB. The outstanding 

topographic features include high, forested plateaus; broad, 

inwardly sloping, dissected plateaus with intricately eroded 

escarpments; terraced plateaus and plains studded with buttes, 

mesas, arches, and spires; eroded domes ringed by cuestas; flatbottomed valleys flanked by parapet-like ridges; snowcapped, 

laccolithic mountains; and, everywhere, tortuous, vertically 

walled canyons (fig. 9). As Powell (1895) wrote,

Every river entering *** has cut a canyon; every 

lateral creek has cut a canyon; every brook runs in a 

canyon; every rill born of a shower and born again of 

a shower and living only during these showers has cut 

for itself a canyon; so that the whole [area] is 

traversed by a labyrinth of these deep gorges.

The Colorado Plateaus physiographic province in the UCRB 

and vicinity includes the Uinta, Piceance, Henry Mountains, 

Kaiparowits, Kaibito, Blanding, and Black Mesa Basins; the 

Uncompahgrc, Defiance, Kaibab, Coconino, and San Francisco 

Plateaus; the High Plateaus region of Utah, which includes the 

Paunsaugunt, Table Cliffs, Aquarius, Awapa, Fish Lake, and 

Wasatch Plateaus; the Capitol Reef and Paradox Basin Fold and 

Fault Belts; the Castle Valley, San Rafael Desert, Grand ValleyMontrose Valley, and Gallup Sags; the Marble and Four Corners 

Platforms; and the San Rafael Swell, Circle Cliffs Uplift, 

Monument Upwarp, Tyende Saddle, Douglas Creek Arch, Chuska 

Mountains, Echo Cliffs, Preston Bench, and Mogollon Slope 

(pi. 1). Six groups of laccolithic mountains the Abajo, Henry, 

and Carrizo Mountains, Sleeping Ute Mountain, Navajo 

Mountain, and La Sal Mountains are scattered throughout these 

areas. Although the Axial Basin Arch continues the structural

trend between the Middle and Southern Rocky Mountains (Stone, 

1986, fig. 1) and probably should be included in one of those physiographic provinces, traditionally, and in this report, it is considered part of the Colorado Plateaus province.

The Colorado Plateaus province, in general, lies between 

altitudes of 5,000 and 7,000 ft; but, as described by Gregory and 

Moore (1931, p. 12-14):

*** the downward departures *** are approximately equal in amount to the upward departures ***. 

For the region as a whole, changes in altitude are 

abrupt; gentle slopes arc conspicuously absent. 

Above the valley floors the plateau benches rise by 

steps, bench after bench, and into the benches the 

streams are sunk an equal amount ***. The plateau 

benches are so continuous that canyons which cut 

their edges appear at a distance as insignificant 

breaks in a horizontal skyline ***.

Surfaces of the Uncompahgre, Defiance, and Kaibab Plateaus; the 

High Plateaus region of Utah; and the Chuska Mountains generally lie between altitudes of 7,500 and 11,500 ft; escarpments of 

the inwardly sloping broad plateaus that comprise the Piceance, 

Uinta, Kaiparowits, and Black Mesa Basins crest at altitudes 

between 7,000 and 11,000 ft; peak altitudes of laccolithic mountains and isolated erosional and structurally raised mountains, 

such as Juniper Mountain, Cross Mountain, the Danforth Hills, 

Elk Ridge, Thousand Lake Mountain, and Canaan Peak, range 

from 8,000 to 13,000 ft. Canyons 1,000 to more than 3,000 ft deep 

include Unaweep Canyon and Ute Canyon in the Uncompahgre 

Plateau, Canyon De Chelly in the Defiance Plateau, and numerous 

canyons of the Colorado, Green, San Juan, Dolores, San Miguel, 

Dirty Devil, San Rafael, Escalante, and Paria Rivers.

CLIMATE

The climate of the UCRB varies from arid in the lowlands 

that are in the rain shadow of mountains and plateaus forming 

the western boundary to humid in the mountains and higher 

plateaus. The average annual precipitation ranges from less than 

6 to more than 40 inches (fig. 10), generally increasing with 

increasing altitude (fig. 11). In the part of the UCRB that docs 

not include the San Juan Basin, the average annual precipitation 

is about 15 inches (as discussed later in this report).

Average precipitation amounts can be misleading in arid and 

semiarid parts of the UCRB, where monthly accumulations 

recorded at weather stations can be the result of a single storm or 

a few downpours of local extent (Gregory, 1938, p. 15). In these 

areas, average annual precipitation can vary considerably from 

year to year. At Moab, Utah, for example, the average annual 

precipitation is 8.18 inches, but recorded precipitation has ranged 

from 3.02 inches in 1956 to 15.96 inches in 1918(Sumsion, 1971, 

p. 7). At Scofield Dam, in the Book Cliffs region of Utah, the 

average annual precipitation is 16.0 inches, but precipitation 

ranged from 6.77 to 32.03 in/yr between 1931 and 1975 (Waddell
PHYSICAL SETTING B23

FIGURE 9. Landscapes of the Colorado 

Plateaus physiographic province: 

A. Monument Upwarp looking southwest 

from the Island in the Sky district. In the 

foreground is the White Rim Bench, which 

is capped by the White Rim Sandstone and 

underlain by the Organ Rock Shale, both of 

which are in the Permian Cutler Group (of 

Baars, 1962). In the distance, cliffs of 

Jurassic Wingate Sandstone. Kayenta 

Formation, and Navajo Sandstone rise 

above the Green River at the entrance to the 

Maze. B. Paradox Basin southeast of Moab, 

Utah. La Sal Mountains, underlain by 

Tertiary igneous rocks, rise above cliffs of 

Jurassic Entrada Sandstone.

to ' r-» - * V--"" "V, ' £. » '

and others, 1981, p. 5). The consequence of these observations is 

that one cannot necessarily eliminate the possibility of groundwater recharge occurring in areas with small average annual 

precipitation because in some years, the annual precipitation or 

the accumulation from individual storms in these areas may be so 

large that some precipitation may infiltrate to the water table.

Precipitation in the UCRB predominantly results from eastward moving cyclonic storms in the winter months and northeasterly moving convection cells in the summer months 

(Gregory, 1938, p. 15; lorns and others, 1965, p. 10). The

cyclonic storms (which originate in the Pacific Ocean) bring 

prolonged rain or snow, whereas the convection storms (which 

originate in the Gulf of Mexico) produce brief but intense localized rain. Reflecting these dichotomous sources of precipitation, many areas have dual precipitation peaks one between 

December and March and a second between July and October. 

Examples include the Paradox Basin (Rush and others, 1982), 

Uinta Mountains (Hood and Fields, 1978), Uinta Basin (Price 

and Miller, 1975), San Juan Mountains (Eckel and others, 

1949), Capitol Reef Fold and Fault Belt (Smith and others,
B24 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

BOUNDARY OF;

UPPER COLORADO

RIVER BASIN

o

nj-p'm o ,. 

EXPLANATION 

1 I j Climatic zone indicated in figure 1 1

 20 Line of equal average annual

precipitation, 1951-80 in Colorado, 

1931-60 in remainder of Upper 

Colorado River Basin Interval, in 

inches, is variable

Weather station operated by National 

Oceanic and Atmospheric 

Administration (NOAA)

Weather station operated by U.S. 

Geological Survey during a hydrologic 

study

 AREA EXCLUDED 

FROM STUDY

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 10. Average annual precipitation in the Upper Colorado River Basin and location of sites used in analyses of climatic data.

(Modified from Price and Arnow, 1974; Doesken and others, 1984.)
PHYSICAL SETTING B25

1963), Navajo-Hopi Reservations (Cooley and others, 1969), 

and the High Plateaus region of Utah (Gregory, 1951; Plantz, 

1985). However, some areas, such as the Four Corners Platform 

(Irwin, 1966) and Monument Valley (Gregory, 1938), have a 

single precipitation peak, which occurs between July and 

October. The minimum monthly precipitation often occurs in 

early autumn or late spring but can occur at any time during the 

year from site to site within a geographic area (National 

Oceanic and Atmospheric Administration, 1930-85).'

A substantial amount of precipitation is consumed by evapotranspiration. Evapotranspiralion rates generally decrease 

inversely with altitude as the temperature decreases (fig. 11) but, 

nevertheless, are large throughout much of the study area. For 

example, in the Cottonwood Wash watershed near Cortez, Colo., 

the average annual precipitation is 17 inches; evapotranspiration in 

this area was estimated, on the basis of climate statistics and physiographic features, to range from 60 to 90 percent of the annual 

precipitation from 1979 to 1982 (Geldon, I985a. p. 10-14). At 

Black Mesa, in northeastern Arizona, Eychaner (1983, p. 9 11) 

indicated that as much as 46 percent of the ambient precipitation 

on the Jurassic Navajo Sandstone is consumed by evapotranspiration. At Scofield Dam, in the Book Cliffs region of Utah, 

measured lake evaporation exceeds the average annual precipitation by 26 in/yr (Waddell and others, 1981, p. 6). Total evaporative 

losses from lakes and reservoirs in the Upper Colorado River 

Basin were estimated by the U.S. Water Resources Council (1978, 

p. 17) to be 800.000 acre-ft/yr. In general, evapotranspiration 

exceeds precipitation from April to October; during the remainder 

of the year, especially at altitudes above 6,000 ft, evapotranspiration is a minor component of the water budget (see, for example, 

Waddell and others, 1981, p. 7; Geldon, 1985a, p. 14).

DRAINAGE

The watershed of the Colorado River is the ninth largest 

river system in the country in terms of discharge and the fifth 

largest system in terms of drainage area (Iseri and Langbein, 

1974). West of the Continental Divide, only the Columbia and 

Sacramento Rivers have larger discharges; only the Columbia 

River has a larger drainage area.

The Colorado River is formed by the confluence of five 

major tributaries the Green, Upper Colorado, San Juan, Little 

Colorado, and Gila Rivers. All but the Little Colorado and Gila 

join the Colorado in the upper part of the basin, which was 

formally defined by the Colorado River Compact of 1922. This 

compact officially divided the upper and lower parts of the 

Colorado River watershed at a point 1 mi downstream from the

Includes reports published under the name of predecessors of 

the National Oceanic and Atmospheric Administration, including the 

U.S. Weather Bureau, 1930 to 1964, and the Environmental Science 

Service Administration, 1965 to 1970.

confluence of the Paria and Colorado Rivers near Lees Ferry, 

Ariz. This point has no hydrological significance in terms of 

either the surface-water or ground-water systems.

Prior to 1921, the Colorado River above the confluence with 

the Green River was known as the Grand River, and the 

combined flows of the Green and Grand Rivers were known as 

the Colorado River. On July 25, 1921, the Colorado Legislature 

extended the name "Colorado River" to the headwaters of the 

Grand River for political reasons (Fradkin, 1981, p. 35).

The Little Colorado and Gila Rivers, formerly integral parts 

of the Colorado River system, are now depleted severely by irrigation diversions and are mostly dry channels except during 

seasonally high flows. The Colorado River itself is depleted 

severely by irrigation demands in its lower reaches and no 

longer flows to its historical outlet, the Gulf of California 

(Fradkin, 1981, p. 319-341).

In the upper basin, the Green and Colorado Rivers and their 

tributaries (fig. 12) comprise more than 17,000 mi of streams 

with more than 322,000 acres of lakes and reservoirs 

(U.S. Water Resources Council, 1978, p. 10). The combined 

storage capacity of the 82 largest reservoirs in the basin (individual storage capacities of more than 5,000 acre-ft) is about 

38,000,000 acre-ft (Liebermann and others, 1988, p. 16-18). 

Lake Powell, with a storage capacity of 27,000,000 acre-ft, 

contains 71 percent of the surface-water storage. Other reservoirs with a storage capacity of more than 200,000 acre-ft 

include Flaming Gorge and Fontenelle (Green River), Navajo 

(San Juan River), Strawberry (Strawberry River), Blue Mesa 

(Gunnison River), Lake Granby (Colorado River), McPhee 

(Dolores River), and Dillon (Blue River).

In the words of Powell (1895), the streams of the upper 

basin.

Born in the cold and gloomy solitudes of the 

* * * mountain region, have a strange, eventful 

history as they pass down through gorges, tumbling 

in cascades and cataracts, until they reach the hot, 

arid plains of the Lower Colorado.

The Colorado River begins on the east side of Mount 

Richthofen, in the Front Range of Colorado (lorns and others, 

1965, p. 2). The Green River originates at Peak Lake, beneath 

Fremont Peak in the Wind River Mountains of Wyoming 

(Fradkin, 1981, p. 34-^-2). The two streams converge below the 

White Rim Bench, at the head of Cataract Canyon, 60 mi southeast of Green River, Utah, and 35 mi southwest of Moab, Utah. 

Historically, the Colorado River was constrained in deep 

canyons Cataract, Glen, Marble, and Grand for almost all of 

the more than 500 river miles between the confluence point and 

the Grand Wash Cliffs in Arizona. The lower part of Cataract 

Canyon and most of Glen Canyon are now flooded by Glen 

Canyon Dam and Lake Powell.

The Colorado River at its confluence with the Green has a 

larger discharge but a smaller drainage area. This situation 

results from the distinctly different topography of the two
B26 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

Zone I Zone I

25

15

I I I I I I I I

i I i i i i i 0

4,000 5,000 6,000 7,000 8,000 9,000 10,00011,00012,00013,000

Zone II

CC 

HI

C Y= 0.0021*- 0.012 

Correlation 

coefficient = 0.65

 * 

I I _L

3,000 4,000 5,000 6,000 7,000 8,000 9,00010,00011,00012,00013,000

Zone III

E Y =0.0030*-5.2

Correlation coefficient = 0.89

I I I I _L I I

3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,00011,00012,00013,000

ALTITUDE, IN FEET ABOVE 

NATIONAL GEODETIC VERTICAL DATUM OF 1929

y=-0.0035*+62.3 B 

Correlation 

coefficient = 0.49

LU 4,000 5,000 6,000 7,000 8,000 9,00010,00011,00012,00013,000

OL 

555

LICO

LU

g 5°

LU

D 45

Zone II

LU 40

235 

£

y= -0.0036* + 63.8 

Correlation 

coefficient = 0.83

D

3,000 4,000 5.000 6,000 7,000 8,000 9,00010,00011,00012,00013,000

Zone III

y = -0.0035* +69.6 F 

Correlation coefficient = 0.98

60

55

50

45

40

35

30

25

3,000 4,000 5,000 6,000 7,000 8,000 9,00010,00011,00012,00013,000

ALTITUDE, IN FEET ABOVE 

NATIONAL GEODETIC VERTICAL DATUM OF 1929

FIGURE 11. Relations of precipitation and temperature to altitude in the Upper Colorado River Basin. (Plots / and./ modified 

from Geldon, 1985a, p. 11; plots K and L modified from Cooley and others, 1969, p. 29J
PHYSICAL SETTING B27

Zone IV Zone IV 1 ! I ! I T

G x=0.0038x-6.2 * 

Correlation coefficient = 0.71

T

I 

CJ

35

30

25

20

15

10

5

0

3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,00011,00012,000

ZoneV

o

s

30

25

T

j/=0.0051x-19.0 

Correlation coefficient = 0.98

8,000 9,000 10,000

Zone VI

20

17.5

15

12.5

10

7.5

5

2.5

3,000

K y=0.0022x~2.9

Correlation coefficient = 0.76

_L

4,000 5,000 6,000 7,000

ALTITUDE, IN FEET ABOVE 

NATIONAL GEODETIC VERTICAL DATUM OF 1929

8,000

\ I \ I 

X =-0.0048*+70.7 H 

Correlation 

coefficient = 0.91

3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,00011,00012,000

Zone V

-0.0037x 

Correlation 

coefficient = 0.95

9,000 10,000

Zone VI

35

3,000

y=-0.0028x+68.7 L 

Correlation coefficient = 0.89

4,000 5,000 6,000 7,000

ALTITUDE, IN FEET ABOVE 

NATIONAL GEODETIC VERTICAL DATUM OF 1929

8,000

FIGURE 11. Relations of precipitation and temperature to altitude in the Upper Colorado River Basin. (Plots 7 and J modified from 

Geldon, 1985a, p. 11; plots K and L modified from Cooley and others, 1969, p. 29) Continued.
B28 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

10

94

E;OUNDARY OF

UPPFP COLORADO

RIVER BASIN

EXPLANATION

20 30 Discharge, in thousand cubic 

feet per second

Above scale applies to Colorado and Green 

Rivers and to tributaries near confluence points 

where discharges exceed about 400 cubic feet 

per second. Discharges of Colorado and Green 

River headwaters and tributaries upstream from 

confluence points are shown schematically. The 

historical {pre-Lake Powell) discharge of the 

Colorado River is shown graphically where the 

river leaves the watershed

Approximate point at which discharge was 

measured Number is average annual 

discharge, in cubic feet per second

AREA EXCLUDED 

FROM STUDY

17,850 (Historical) 

12,170 (After Lake Powell)

50

_L_

75 100 MILES 

I

50 75 100 KILOMETERS

FIGURE 12. Watersheds and average discharges of the Green and Colorado Rivers upstream from Lees Ferry, Arizona. (Compiled from 

Druse and Rucker, 1984; Duncan and others, 1984a, 1984b; ReMillard and others, 1984; and White and Garrett, 1982.)
REGIONAL GEOLOGY B29

watersheds. Upstream from the confluence, the Colorado River 

flows mostly through mountainous terrain with a humid 

climate. However, the Green River flows mostly through arid 

and semiarid plains and plateaus.

The Colorado River at its confluence with the Green River 

has an average discharge of about 8,000 ft3/s. The principal 

tributaries of the Upper Colorado River (those with individual 

discharges of more than 150 ft3 /s) are the Gunnison River, 

Roaring Fork, Dolores River, Eagle River, Blue River, and 

Plateau Creek (fig. 12). The Green River at its mouth has an 

average discharge of about 6,600 ft3/s. Its principal tributaries 

are the Yampa River, White River, New Fork, Duchesne 

River, Blacks Fork, San Rafael River, and Price River 

(fig. 12). Downstream from the confluence of the Colorado 

and Green Rivers, four rivers the San Juan, Dirty Devil, 

Escalante, and Paria enter the Colorado River (fig. 12). 

Prior to construction of Glen Canyon Dam and the filling of 

Lake Powell, the Colorado River at Lees Ferry, Ariz., had an 

average discharge of 17,850 ft3/s. After the gates of the dam 

were closed in 1963, the discharge at Lees Ferry (as of 1982) 

averaged 12,170 ft3/s, a net reduction from the preconstruction discharge of 5,680 ft3/s.

The Colorado and Green Rivers gain streamflow from 

tributaries, ground-water discharge, and irrigation return 

flows and are depleted by transbasin diversions, irrigation 

diversions, seepage to aquifers, and evapotranspiration. On 

the basis of measured springflows and previous assessments 

of ground-water contributions by Rush and others (1982), 

URS Corporation (1983), and Warner and others (1985), 

cumulative spring and seep inflows to the Green and 

Colorado Rivers between the most upstream gaging stations 

and Lees Ferry, Ariz., were determined to be 833 ft3/s. On the 

basis of unaccounted gains in these reaches, irrigation return 

flows are estimated to be at least 739 ft 3 /s. Less than 

10 percent of the streamflow in the Green and Colorado 

Rivers, thus, is attributed to direct ground-water discharge 

and irrigation return flow.

Transbasin diversions occur from the Colorado, Green, 

Fraser, Blue, Gunnison, Eagle, Fryingpan, Little Snake, Big 

Sandy, Duchesne, Strawberry, Navajo, Piedra, San Juan and 

San Rafael Rivers, Los Pinos River, the Williams and Roaring 

Forks of the Colorado River, and the Henrys Fork of the Green 

River (Liebermann and others, 1988, p. 14 15). According to 

Liebermann and others (1988, p. 13), total transbasin diversions 

from the UCRB during water years 1973 82 averaged 

1,020 ft3/s annually.

Water for irrigation is diverted from the Colorado and Green 

Rivers and most sizable tributaries. Measured losses from the 

Green River in Wyoming average 269 ft3/s. Most of this is attributable to irrigation diversion, but some may be due to evaporation 

from Fontenelle Reservoir. Irrigation diversions from the 

Colorado River in Middle Park and Grand Valley, Colo., are estimated to average as much as 353 ft3/s. If about 65 percent of the

water diverted for irrigation in the Upper Colorado River Basin 

returns to streams, as indicated by the U.S. Water Resources 

Council (1978, p. 17), then on the basis of return flows reported 

earlier (739 ft3/s), total irrigation diversion from the Colorado and 

Green Rivers could be about 1,140 ft3/s.

Since 1963, the largest water losses from the Colorado 

and Green Rivers have been the result of storage in Lake 

Powell, evaporation from the reservoir, and seepage of water 

from the reservoir into adjacent Mesozoic and Paleozoic 

rocks. According to Thomas (1986, p. 14 15), annual 

leakage from the reservoir to the underlying aquifers is about 

600,000 acre-ft/yr. As a result of this leakage, ground-water 

levels in wells within 10 mi of the reservoir are known or estimated (by finite-difference modeling) to have risen by less 

than 25 to 500 ft between 1963 and 1983.

Except for regulated reaches downstream from dams, 

streamflows vary substantially during the year throughout the 

watershed. Seasonal flows typically are highest in spring and 

early summer and lowest in late fall and early winter. About 

70 percent of the annual runoff occurs from early April to late 

July (U.S. Water Resources Council, 1978, p. 10). This runoff is 

derived mostly from snowmelt. Thunderstorms produce high 

flows of short duration from July through October. From 

November to April, most streams are at or near base flow, except 

during periods of storm-induced runoff. As seen in the 1984 

records of the Colorado River below Glenwood Springs, Colo., 

and the Green River near Green River, Wyo. (fig. 13), monthly 

discharges of perennial streams in mountainous regions are 

similar in timing to, but larger in amplitude (per square mile of 

drainage area) than, these fluctuations in lowland regions. As 

seen in the 1982 record of the Colorado River at Lees Ferry, Ariz. 

(fig. 13), seasonal discharge fluctuations are suppressed in 

reaches regulated by dams; such discharge fluctuations are 

controlled mainly by the timing of demands for water.

REGIONAL GEOLOGY

Rocks exposed in the UCRB are Precambrian to Tertiary in 

age (fig. 14). The Precambrian and Paleozoic rocks typically are 

exposed in the center and on the flanks of uplifted areas. 

Mesozoic rocks have widespread surface exposure, particularly 

in the southern part of the UCRB. Tertiary sedimentary rocks 

form most of the surface area in the Piceance, Uinta, Sand 

Wash, and greater Green River Basins. Tertiary intrusive and 

extrusive rocks are widespread in the Colorado Plateaus and 

Southern Rocky Mountains physiographic provinces. Thrust 

faults, particularly in the Overthrust Belt, Gros Ventre Range, 

Wind River Mountains, and Uinta Mountains, and high-angle 

normal and reverse faults in the High Plateaus region, 

Uncompahgre Plateau, Paradox Basin, and the Southern Rocky 

Mountains have had a pronounced effect on the distribution of 

the exposed rocks.
B30 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

700

600

500

400

300 -

200

100 -

A. Station 09085100, Colorado River below 

Glenwood Springs, Colo.; drainage area 

= 6,013 square miles

B. Station 09217000, Green River near Green 

River, Wyo.; drainage area = 9,740 square 

miles

C. Station 0938000, Colorado River at Lees 

Ferry, Ariz.; drainage area = 111,800 square 

miles

OCT NOV DEC 

1983 

1981

JAN FEE MAR APR MAY JUNE JULY AUG SEPT

1984 

1982

FIGURE 13. Total monthly discharges of the Colorado River below Glenwood Springs, Colorado, 

and the Green River near Green River, Wyoming, during water year 1984, and for the Colorado 

River at Lees Ferry, Arizona, during water year 1982. (Water year 1984 discharge for the Colorado 

River at Lees Ferry is not shown because of atypically large releases from Glen Canyon Dam in 

response to floodwaters entering Lake Powell during that year.)

Precambrian granitic, metamorphic, and sedimentary rocks 

underlie the Paleozoic rocks (fig. 15) with subtle to pronounced 

angular unconformity. Archean to Late Proterozoic granitic and 

metamorphic rocks compose most of the Precambrian complex. 

However, slightly metamorphosed to unmetamorphosed sedimentary and volcanic rocks are present in a few areas. In the 

San Juan Mountains and vicinity, an 8,000-ft-thick sequence of 

quartzite, slate, and phyllite, belonging to the Early and Middle 

Proterozoic Uncompahgre Formation, underlies the Paleozoic 

rocks. In and near the Uinta Mountains and Uinta Basin, a 

24,000-ft-thick sequence of quartzite, sandstone, and shale, 

belonging to the Middle and Late Proterozoic Uinta Mountain

Group, underlies the Paleozoic rocks. From the Grand Canyon to 

the vicinity of the Paria River in northeastern Arizona and southeastern Utah, a 13,000-ft-thick sequence of quartzite, sandstone, 

conglomerate, breccia, shale, limestone, and basalt, belonging to 

the Middle to Late Proterozoic Unkar Group, Nankoweap 

Formation, and Chuar Group, underlies the Paleozoic rocks.

The thickness of Paleozoic formations present in the UCRB 

ranges from 0 to about 18,000 ft (fig. 16). All systems except the 

Silurian are represented. The Paleozoic rocks were deposited 

during five advances and retreats of the sea. Cambrian to Lower 

Mississippian formations consist mostly of limestone and dolomite, although thick intervals of sandstone, quartzite, and shale
REGIONAL GEOLOGY B31

43

BOUNDARY OF 

UPPER COLORADO - 

RIVER BASIN 41'

EXPLANATION 

^H^g Tertiary igneous rocks 

|____ Tertiary sedimentary rocks

Mesozoic rocks 

|____| Paleozoic rocks 

| I Precambrian rocks

 High-angle fault Dashed where 

concealed

Thrust fault Dashed where 

concealed. Teeth on upper plate

Graben 

Fault zone

Anticline Arrow shows direction 

of plunge

Syncline 

Monocline

A A' Location of geologic section 

shown in figure 90

 AREA EXCLUDED 

FROM STUDY

0 25 50 75 100 KILOMETERS

FIGURE 14. Generalized geology of the Upper Colorado River Basin and vicinity. 

(Modified from Geldon, in press, pis. 1 and 2.)
B32 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

110=

Landcr

108 C

s~ \ Rock Springs I

. No data \ o i

1/ Rawlins

EXPLANATION

Middle and late Proterozoic 

unmetamorphosed to slightly 

metamorphosed sedimentary rocks

Archean and Proterozoic granitic 

rocks

Archean and Proterozoic metamorphic 

rocks

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

 AREA EXCLUDED 

FROM STUDY

0 25 50 75 100 MILES 

I_____|_____|_____I_____i

0 25 50 75 100 KILOMETERS

FIGURE 15. Distribution of Precambrian rocks in the Upper Colorado River Basin. 

(Modified from Geldon, in press, pi. 4.)
REGIONAL GEOLOGY B33

110°

43-

42

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

Thickness of Paleozoic rocks, 

in feet

0

0 to 2,000 

2.000 to 4.000 

4.000 to 6,000 

6,000 to 8,000 

8,000 to 10,000 

10,000 to 14,000 

14,000 to 18.000

 AREA EXCLUDED 

FROM STUDY

0 25 50 75 100 MILES 

I_____|_____|_____1_____|

0 25 50 75 100 KILOMETERS

FIGURE 16. Distribution and thickness of the Paleozoic rocks in the Upper Colorado River Basin. 

(Modified from Geldon, in press, pi. 3.)
B34 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

are present. These lower and middle Paleozoic formations are 

overlain by much thicker Upper Mississippian to Permian 

formations. The younger formations consist mostly of sandstone, conglomerate, and shale, but variably thick intervals of 

carbonate rocks occur, and thick deposits of bedded to diapiric 

anhydrite and halite are present, particularly in the Paradox and 

Eagle Basins. Deposition of the Upper Mississippian to 

Permian formations was affected substantially by uplift and 

subsidence. Consequently, pronounced lateral variations in 

lithology are characteristic of the Pennsylvanian and Permian 

rocks.

The Paleozoic rocks are overlain in most areas by Triassic 

formations that are predominantly composed of shale. Locally, 

lower parts of the Triassic formations in contact with the 

Paleozoic rocks consist partly or entirely of sandstone, 

conglomerate, or limestone (fig. 17). Contacts between the 

Paleozoic and Triassic rocks are gradational to unconformable. 

In small areas within the Southern Rocky Mountains and 

Piceance Basin, the Triassic rocks were removed by preJurassic erosion, and the Wingate and Entrada Sandstones of 

Jurassic age overlie the Paleozoic rocks with pronounced 

angular unconformity. Triassic rocks also are missing in a few 

small areas within the Overthrust Belt. In these areas, the 

Wasatch Formation, a unit of Tertiary age consisting mostly of 

shale and fine-grained sandstone, unconformably rests upon the 

Paleozoic rocks (fig. 17). The total thickness of Mesozoic and 

Tertiary rocks overlying the Paleozoic rocks ranges from 0 to 

about 27,000 ft (fig. 18).

GENERAL HYDROLOGIC PROPERTIES 

OF THE PALEOZOIC ROCKS

The 11 hydrogeologic units consisting of Paleozoic rocks 

each possess distinctive lithologic and hydrologic properties, 

which are summarized in table 5. For comparison, typical 

ranges in permeability and hydraulic conductivity exhibited by 

sedimentary rocks are shown in figure 19. Use of the relative 

terms small, moderate, and large in discussions of permeability 

and hydraulic conductivity in this report are referenced to this 

figure. In regard to transmissivity and yield, the following 

ranges apply:

Relative 

term

Small 

Moderate

Large

Transmissivity 

(feet squared 

per day)

0.0005-1 

1-100 

100-50,000

Yield 

(gallons 

per minute)

<l-50 

50-500 

500-50,000

Indicative of variable lithology and tectonic setting, all 

hydrogeologic units exhibit ranges in hydrologic properties 

spanning several orders of magnitude (table 5). Variations 

within a hydrogeologic unit vertically can be as large as variations laterally across the UCRB. Ranges overlap but, in general, 

aquifers are characterized by larger values of unit-averaged 

porosity, permeability, and hydraulic conductivity, composite 

transmissivity, and sustained yields than confining units.

All hydrogeologic units are most permeable and, therefore, 

have the largest yields of water in uplifted areas. Fractures associated with uplift serve as conduits for downward percolation of 

meteoric water and streamflow and connect confining units 

with aquifers, resulting in a localized capability of confining 

units to supply water. Conversely, all hydrogeologic units 

decrease in permeability and water-supply capability away from 

uplifted areas (toward structural basins) as fractures associated 

with uplift become less common. The permeability and watersupply capabilities of hydrogeologic units in structural basins 

have been reduced further by compaction beneath thousands of 

feet of Mesozoic and Tertiary rocks and cementation by 

mineral-laden solutions migrating down structural and topographic gradients.

Among rock types commonly present in the hydrogeologic 

units composed of Paleozoic rocks, sandstone, with a median 

porosity of 8.0 percent, is the most porous (fig. 20). Next, in order 

of decreasing median porosity, are dolomite (4.6 percent), limestone (2.8 percent), shale (2.4 percent), and anhydrite and halite 

(0.4 percent). Among clastic rocks, porosity is smallest in sandstone cemented with silica, calcite, dolomite, or anhydrite; intermediate in sandstone with matrix minerals, such as glauconite or 

clay; and largest in generally friable, micaceous and arkosic sandstone (fig. 21). The porosity of clastic rocks also increases as the 

grain size increases and is larger in coarse-grained and gravelly 

sandstone than in shale or very fine-, fine-, or medium-grained 

sandstone.

Among carbonate rocks, porosity generally is smallest in 

varieties containing impurities that impart a laminar texture, 

such as shaly, carbonaceous, or algal limestone and dolomite, 

and largest in varieties that are susceptible to dissolution around 

inclusions, such as cherty, anhydritic, or vuggy limestone and 

dolomite. The porosity of carbonate rocks also varies with 

increasing graininess and is larger in chalky, earthy, sandy, and 

sucrosic varieties than in crystalline and cryptocrystalline (finegrained) varieties. The porosity of brecciated limestone and 

dolomite appears to be small, despite an inherently fractured 

nature, and probably was reduced by calcite cement in the fractures of the samples that were analyzed.

Pore-scale permeability, like porosity, is influenced mainly 

by sedimentary composition and texture. The median pore-scale 

permeability of sandstone in this study was 4 times larger than 

the median pore-scale permeability of dolomite and 10 times 

larger than the median pore-scale permeability of limestone
GENERAL HYDROLOGIC PROPERTIES OF THE PALEOZOIC ROCKS B35

110°

42°'

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

Upper part

of Goose Egg

Formation

EXPLANATION

Area where Paleozoic rocks crop 

out

Area where Paleozoic rocks are 

missing because of erosion or 

nondeposition or are thrust under 

Precambrian rocks

Area where Mesozoic rocks are 

missing and Paleozoic rocks are 

overlain by the Tertiary Wasatch 

Formation

Mesozoic lithologies

Shale with thin sandstone, limestone, 

or anhydrite layers

Shale and limestone with sandstone 

and anhydrite layers

Sandstone and conglomerate with 

shale layers

Formation contact

Facies change within a formation

AREA EXCLUDED 

FROM STUDY

75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 17. Lithology of the Mesozoic rocks in contact with Paleozoic rocks in the Upper Colorado River Basin

(Modified from Geldon, in press, pi. 4.)
B36 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

110

43

42

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

Thickness of Mesozoic and 

Tertiary rocks, in feet

0 to 2,500 

0 to 5,000 

2,500 to 5,000 

5.000 to 10.000 

10,000 to 15,000 

15,0001020,000 

20.000 to 25,000 

25,000 to 27,000

Paleozoic rocks missing 

because of erosion or 

nondeposition

AREA EXCLUDED 

FROM STUDY

25 50 75 100 MILES

I I I I I

0 25 50 75 100 KILOMETERS

FIGURE 18. Thickness of the Mesozoic and Tertiary rocks above the Paleozoic rocks in the Upper Colorado River Basin.

(Modified from Geldon, in press, pi. 3.)
TABLE 5. Summary oflithologic and hydrologic properties of the hydrogeologic units composed of Paleozoic rocks in the Upper Colorado 

[<, less than]

£3

A

Canyonlan

c

3

OJD

C

C

c 

o

£

o 

U

_

OJ

'3

S"

S-i

1

3

Hydrogeologic 

unit

Park City-State 

Bridge zone

Weber-De Chelly 

zone

Cutler-Maroon 

/one

Paradox-Eagle 

Valley subunit

Belden-Molas 

subunit

Madison aquiferDarwin-Humbug 

zone

Madison aquiferRedwall-Leadville

General 

lithology

Variable proportions of shale, 

sandstone, carbonate rocks, 

gvpsum-anhvdrite, chert, and

phosphorite.

Quartz sandstone with minor 

conglomerate, shale, and 

carbonate rocks.

Variable proportions of arkosic to 

quartzose sandstone, conglomerate, shale, and carbonate 

rocks.

Variable proportions of shale, 

gypsum-anhydrite, halite, 

limestone, and dolomite, 

with subordinate sandstone.

Shale with subordinate carbonate 

rocks and minor gypsumanhydrite and sandstone.

Interbedded sandstone, shale, 

carbonate rocks, and breccia, 

with minor gypsum.

Limestone and dolomite with

minor bedded and nodular 

chert, shale, and sandstone. 

Increasing dolomite in proportion to limestone from uplifts

to basins.

Thickness 

(feet)

0-800

0-4,000

0-16,500

0-9,700 

where bedded: 

salt diapirs as 

much as 15.000

0-UOO

0-800

0-2.500

Porosity 

(percent)

Range <0.1 to 22. 

Median values are: 

sandstone - 7.4; 

limestone - 3.4;

Unit- averaged range 

is 2 to 6.

Range <0. 1 to 28. Median 

value for sandstone is 

8.0. Unit-averaged range 

is 1 to 28.

Range 0.4 to 20. 

Median values are: 

arkosic sandstone - 1 1 .6; 

quartz sandstone - 7.3; 

limestone - 2.4. 

Unit-averaged range 

is 2 to 14.

Range<0.1 to 3 2.

Median values are:

dolomite - 6.1; 

limestone - 3.5; 

shale- 1.8; 

anhydrite - 0.4; 

halite - 0.4.

Unit-averaged range 

is <1 to 6.

Range and median values 

for individual rock types 

probably similar to 

above unit. Unitaveraged range is

<2 to 6.

Range 1.4 to 16 in 13 

samples of sandstone.

Range 0.3 to 22.

Median values are:

dolomite- 6.5; 

limestone - 1 .7. 

Unit- averaged range

is <1 to 11.

Permeability 

(millidarciesl

Pore-scale range is <0.01 

to 1,450. Local-scale range 

is 0.0049 to 330. Medians 

of pore-scale values are:

sandstone - 0.04; 

limestone - 0.01.

Strong correlation between

porositv and pore-scale permeability for sandstone. Range of 

pore-scale values is <0.01 to 

3,080. Range of local-scale 

values is 0.014 to 380. Median 

pore-scale sandstone permeability value is 0.40.

Pore-scale range is 0.0007 1 to 

232. Local-scale range is 

0.00078 to 68. Medians of 

pore-scale values are: sandstone - 0.46; limestone - 0.01

Pore-scale range is <0.0001

to 3,460. Local-scale range

is 0.0031 to 550. Medians 

of pore-scale values are: 

dolomite - 0.21; 

limestone - 0.10; 

anhvdrite and halite - <0.01 ;

sandstone - 0.01; 

shale -<0.01;

Range in pore-scale permeability 

and median values for individual rock types probably 

similar to above unit. Range in 

local-scale permeability is

0.001 2 to 130.

Pore-scale permeabilitv of sandstone ranged from 0.08 to 60 

in 13 samples. Local-scale 

permeability of dolomite, 

sandstone, and shale in a drillstem test near Maybell, Colo.,

No correlation between porositv

and permeability. Pore-scale

range is <0.01 to 940. Localscale range is 0.02 to 1 ,800. 

Medians of pore-scale

values are: dolomite - 0.10;

limestone - <0.01 .

Hydraulic 

conductivity 

(feet per day)

Range is 0.0000 12 

to 0.80, with a 

median of 0.006. 

Unit-averaged

range is 0.00001 

tol.

Range is 0.000034

to 61, with a 

median of 0.012. 

Unit-averaged 

range is 0.00005 

to 20.

Range is 0.000002 

to 10, with a 

median of 0.15. 

Unit-averaged 

range is 0.00005 

to 10.

to 1.5, with a 

median of 0.005. 

Unit-averaged 

range is 0.00001 

to 0.03.

Range is 0.00001 3 

to 0.54, with a 

median of 0.0046. 

Unit-averaged 

range is 0.00001

to 0.10.

0.71 in Maybell 

drill-stem test.

Range is 0.00005

to 200, with a

median of 0.023. 

Unit-averaged 

range is 0.00005

to 200.

Transmissivity 

(feet squared 

per day)

Composite values range fro

0.005 to 70, depending on 

lithology and developmen

fracture and solution chan

nels. Largest values in 

uplifted areas.

Composite values range fro

0.01 to 6,000, depending 

cementation and to a less

degree, on fracturing. Val

decrease from uplifted ar

to basins.

Composite values range fro

0.0005 to 10,000, depend

on thickness, lithology, a

development of fractures 

solution channels. Larges

values in uplifted areas.

Transmissivity probably

depends on lithology and 

the development of fractu

and solution channels. Ba

on lithology alone, compo

transmissivitv is estimate

to range from 0.05 to 15.

Composite values range fro

0.001 to 50, depending 

mainly on development o

fractures and solution cha

nels, which decrease awa

from uplifted areas.

Composite transmissivity e

Maybell drill-stem test, ba

on thickness and hydrauli

conductivity; could be as 

much 1,000 where aquife

consists mostly of fractur

and cavernous limestone.

Composite values range fro

0.01 to 47,000, primarily

depending on developmen

fractures and solution cha

nels, which decrease awa

from uplifted areas.
TABLE 5. Summary oflithologic and hydrologic properties of the hydrogeologic units composed of Paleozoic rocks in the Upper Colorado River 

[<, less than]

Four Corners aquifer system

Hydrogeologic 

unit

Elbert-Parting 

confining unit

Bighorn aquifer

Gros Ventre 

confining unit

Flathead aquifer

General 

lithology

Variable proportions of shale, 

sandstone, quartzite, limestone, dolomite, and gypsumanhydrite.

Limestone and dolomite with 

subordinate shale and minor 

sandstone.

Shale with subordinate sandstone 

and carbonate rocks.

Sandstone and quartzite with 

subordinate carbonate rocks, 

shale, and conglomerate.

Thickness 

(feet)

0-700

0-3,000

0-1,100

0-800

Porosity 

(percent)

Range in the Four 

Corners area is 0.3 to 

12. Median values are: 

sandstone - 6.1; 

dolomite - 1.9. 

Unit-averaged range 

is <2 to 5.

Based on laboratory and 

geophysical measurements at four sites, 

known range is 0. 1 to 

13. Unit-averaged range 

is 1 to 5.

No data.

In one borehole, geophysically determined range is 

0.5 to 24; median is 12.

Permeability 

(millidarcies)

For the Four corners area, porescale range is <0.01 to 179, 

and local-scale range is 0.021 

to 95. Medians of pore-scale 

values are: sandstone - 0.42; 

dolomite - <0.01.

Based on 56 measurements, 

known range in pore-scale 

permeability is <0.01 to 157. 

Local-scale permeability at 13 

sites ranges from 0.029 to 23.

Based on one drill-stem test in 

this unit and three injection 

tests in Proterozoic shale, estimated range in local-scale 

permeability is <0. 1 8 to 29.

Based on six drill-stem tests, 

known range in local-scale 

permeability is 0.003 to 42.

Hydraulic 

conductivity 

(feel per day)

Range in the Four 

Corners area is 

0.000051 to 0.25. 

with a median 

of 0.004. Unitaveraged range is 

0.00005 to 0.25.

Conversion inin-situ 

permeability data 

indicates a range 

of 0.000071 to 

0.056, with a 

median of 0.007.

Conversion of insitu permeability 

data indicates a 

range of 0.00044 

to 0.07.

Conversion of 

local-scale 

permeability data 

and two aquifer 

tests of Precambrian quartzite 

indicate a range 

of 0.000007 to 3.

Transmissivity 

(feet squared 

per day)

Composite values in the Fou

Corners area range from 

0.008 to 200, depending 

mainly on lithology and 

the degree of fracturing.

Composite values based on 

thickness and hydraulic 

conductivity at 1 1 sites 

range from 0.1 to 6.

No data.

Based on six drill-stem tests 

the UCRB and three flow

well tests in the Bighorn 

Basin, range in composite 

transmissivity probably is 

0.001 to 300, depending o

degree of fracturing and 

cementation.
GENERAL HYDROLOGIC PROPERTIES OF THE PALEOZOIC ROCKS B39

SMALL MODERATE

SANDSTONE

LARGE

CEMENTED FRIABLE

SHALE

UNFRACTURED FRACTURED

CARBONATE ROCKS

UNFRACTURED

10 10

-5

10

-4

10

-3

10

-2

10

-1

10

I

FRACTURED

1CT

1

CAVERNOUS'

10* 10° 10° 10' 10°

PERMEABILITY, IN MILLIDARCIES

J_ J_

10 10

-7 10"

10

-5

10

-4

10

-3

10 10 1 10 10 

HYDRAULIC CONDUCTIVITY, IN FEETHER D>

10

FIGURE 19. Range in typical permeability and hydraulic-conductivity values of sedimentary rocks. 

(Modified from Freeze and Cherry. 1979. p. 29; Heath, 1983, p. 13.)

(fig. 22). Median values of pore-scale permeability for shale, 

anhydrite, and halite were found to be less than 0.01 millidarcy 

(md), and a few values in the range of 0.0001 to 0.01 md were 

obtained for each of these rock types. The number of evaporite 

analyses may be insufficient to be representative of evaporite 

permeability regionwide. By way of comparison, Thayer (1983, 

p. 7) reported that the pore-scale permeability of four samples 

of Mississippian anhydrite in and near the Powder River Basin 

of Montana and Wyoming ranged from 0.01 to 0.06 md, with a 

mean value of 0.03 md. Kreitler and others (1985, p. 151) 

reported that bedded halite in the Salado Formation of Permian 

age at Carlsbad, N. Mex. (location of city shown on pi. 1) was 

found to have pore-scale permeability ranging from 0.0001 to 

0.001 md and local-scale permeability ranging from 0.003 to 

0.02 md.

Sandstone and carbonate textures affect pore-scale permeability in much the same manner as they affect porosity 

(fig. 23), although some varieties of sandstone, limestone, and 

dolomite were found to be more or less permeable than otherwise would be expected from their relative porosity. Consistent 

with results reported by McComas (1963) for the Paradox 

Basin, algal limestone samples were found to have disproportionately large permeability with respect to porosity. McComas 

attributed this situation to inherent vugginess in algal reef 

deposits. Several varieties of limestone, including anhydritic, 

cherty, shaly, sucrose, and chalky varieties, were found to be 

more permeable than corresponding varieties of dolomite with

larger porosity. This may reflect a tendency reported by 

McComas of dolomite formed by replacement of limestone to 

have many unconnected vugs causing small permeability 

despite large porosity.

Because of lithologic variability, carbonate rocks and sandstone within hydrogeologic units display little correlation 

between pore-scale permeability and sampling depth. In the 

Redwall-Leadville zone of the Madison aquifer, for example, 

the pore-scale permeability of dolomite has the same range at 

nearly every depth sampled (fig. 24). Similarly, in the WeberDe Chelly zone of the Canyonlands aquifer, the range in the 

pore-scale permeability of sandstone is virtually independent of 

sampling depth. However, in the latter hydrogeologic unit, 

median values of pore-scale permeability decrease with proximity to land surface. These observations imply that the porescale permeability of sandstone aquifers probably is affected by 

leaching of cementing minerals from outcrops and near-surface 

horizons and redeposition of these minerals in deeper horizons. 

In carbonate aquifers, pore-scale permeability may be independent of depth because of processes that occurred in the distant 

past, prior to the rocks being buried to present depths. Such 

processes could include: (1) Diagenetic alteration of limestone 

to dolomite by seawater shortly after deposition; and (2) development of karst topography during times when rocks that are 

now deeply buried were at or near the surface (particularly 

during the Pennsylvanian-Permian uplift of the ancestral Rocky 

Mountains).
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HYDROLOGIC PROPERTIES OF THE FOUR CORNERS AQUIFER SYSTEM B41

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Cherty

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Silty

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Medium-grained

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Anhydritic

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Shale

Quartzite

Anhydrite 

Halite

SANDSTONE MISCELLANEOUS

FIGURE 21. Relation of porosity to variations in the composition and texture of Paleozoic 

sedimentary rocks of the Upper Colorado River Basin.

HYDROLOGIC PROPERTIES OF THE 

FOUR CORNERS AQUIFER SYSTEM.

According to Laney and Davidson (1986, p. 6), an aquifer 

system is defined as

*** a heterogeneous body of intercalated permeable and poorly permeable material that functions 

regionally as a water yielding hydraulic unit; it 

comprises two or more permeable beds (aquifers) separated at least locally by aquitards (confining units) that 

impede ground-water movement but do not greatly 

affect the regional hydraulic continuity of the system.

Within the UCRB, the Paleozoic rocks from the top of the 

Precambrian rocks that form the basal confining unit to the top 

of the Darwin-Humbug zone of the Madison aquifer that lie 

immediately below the Four Corners confining unit satisfy the 

criteria of Laney and Davidson (1986) to be considered a single 

aquifer system because: (1) Confining units within the interval, 

although regionally extensive, generally are much thinner than 

aquifers; (2) in many places, confining units within the interval 

are no less permeable than aquifers and transmit water with the 

aquifers as a single entity; and (3) confining units within the 

interval pinch out locally, such that overlying and underlying 

aquifers are in direct contact.
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HYDROLOGIC PROPERTIES OF THE FOUR CORNERS AQUIFER SYSTEM B43

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Chalky

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Phosphatic 

Fine-grained

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Coarse-grained 

Gravelly

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Quartzitic 

Anhydritic 

Glauconitic

Quartzitic

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Anhydrite 

Halite

g

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0.032

0.01

0.0001

LIMESTONE

FIGURE 23.

DOLOMITE SANDSTONE MISCELLANEOUS

-Relation of pore-scale permeability to variations in the composition and texture 

of Paleozoic rocks of the Upper Colorado River Basin.

The Four Corners aquifer system (table 1) consists, in 

ascending order, of the Flathead aquifer, Gros Ventre confining 

unit, Bighorn aquifer, Elbert-Parting confining unit, and 

Madison aquifer. The Madison aquifer is subdivided into two 

lithologically distinct zones: the Redwall-Leadville zone and 

the Darwin-Humbug zone. Each of the aquifers, confining units, 

and zones, except the Madison aquifer, is named after component geologic units that typify the water-transmitting properties 

of the hydrogeologic unit. The name "Madison aquifer' 1 is 

extended into the UCRB from the adjacent Northern Great 

Plains region (Downey, 1984). The Four Corners aquifer system 

is named for the importance of included aquifers in the four 

States that meet at the Four Corners Arizona, Colorado, New 

Mexico, and Utah. The aquifer system name is not meant to be 

areally restrictive; included aquifers are equally important in the 

Wyoming part of the UCRB.

FLATHEAD AQUIFER

The Flathead aquifer consists of the Tintic Quartzite, 

Tapeats Sandstone and equivalents, Flathead Sandstone, 

lower part of the Lodore Formation, Sawatch Quartzite, and 

Ignacio Quartzite (table 1). Component geologic units are 

Early to Late Cambrian in age and become younger from west 

to east. The ability of these component geologic units to 

supply water to wells and springs depends mostly on the

amount of cementation by silica and carbonate minerals and 

the degree of fracturing, which are related to past and present 

structural settings. In many areas, the component geologic 

units are so tightly cemented that they are not a dependable 

source of water. The Ignacio Quartzite in southwestern 

Colorado, for example, was considered by Whitfield and 

others (1983, table 3) to yield water only through fractures. In 

contrast, where component geologic units are friable to 

moderately cemented, they are reliable sources of water. The 

Flathead Sandstone in the Rawlins Uplift, for example, 

readily yields water to wells (Berry, 1960, p. 14). Because of 

these regional variations in water-supply capability, the 

Flathead aquifer can be expected to function as an aquifer 

subregionally in the UCRB.

THICKNESS AND LITHOLOGY

The Flathead aquifer is 0 to more than 800 ft thick (fig. 25). 

Throughout the region, the aquifer consists almost entirely of 

friable to quartzitic sandstone and quartzite, some of which is 

conglomeratic. In most areas, a basal conglomerate, a few feet 

to more than 50 ft thick, is present. Carbonate rocks account for 

5 to 20 percent of the aquifer and increase toward depositional 

centers, particularly in northwestern Colorado, where the 

sandstone and quartzite commonly are dolomitic. Shale layers 

become more prevalent toward the upper part of the aquifer and 

can be nearly as abundant as sandstone and quartzite layers on 

the southern and eastern edges of the UCRB. Component
REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

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ZONE OF MADISON 

AQUIFER, DOLOMITE

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6. WEBER-DE CHELLY ZONE _ 

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AQUIFER, SANDSTONE

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PERMEABILITY, IN MILLIDARCIES 

EXPLANATION

Range in pore-scale permeability Dashed between outliers 

Bar is the median value at the sampling depth. Asterisk next to bar 

indicates median is less than the smallest value on the x-axis. Number 

in parentheses is the number of analyses at the sampling depth

Outlier at sampling depth

FIGURE 24. Relation of pore-scale permeability to depth below land surface in the Redwall-Leadville zone 

of the Madison aquifer and Weber-De Chelly zone of the Canyonlands aquifer.
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS AQUIFER SYSTEM B45

43

42

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

Area where Flathead aquifer is missing 

because of erosion or nondeposition

Area where Flathead aquifer consists 

of sandstone, quartzite, and 

conglomerate with less than 20 

percent shale or carbonate interbeds

Area where Flathead aquifer consists 

of sandstone, quartzite, and 

conglomerate with 20 to 45 percent 

shale interbeds

Area where Flathead aquifer consists 

of sandstone, quartzite, and 

conglomerate with 20 to 45 percent 

shale and carbonate interbeds

Line of equal thickness Location is 

approximate in Wyoming and 

northeastern Utah. Interval is 200 feet

 AREA EXCLUDED 

FROM STUDY

0 25 50 75 100 MILES

I_____|_____[_____|_____|

0 25 50 75 100 KILOMETERS

FIGURE 25. Thickness and lithology of the Flathead aquifer. 

(Modified from Geldon, in press, pi. 6.)
B46 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

geologic units in the Flathead aquifer are overlain in most areas 

conformably to gradationally by Cambrian shale and carbonate 

formations. However, in some areas, such as the eastern Great 

Divide Basin, eastern Uinta Mountains, and the Sawatch Range, 

component geologic units are overlain unconformably by 

carbonate and clastic rocks of Cambrian to Mississippian age.

POROSITY AND PERMEABILITY

Virtually no quantitative information regarding the porosity 

of the Flathead aquifer was found. Geophysically determined 

porosity in a borehole near Eagle, Colo., ranged from 0.5 to 

24 percent, with a median value of 12 percent (fig. 26). Porosity 

values of 10 percent or less at depths of 10,945, 11,005, and 

11,040 ft in this borehole probably correspond to intervals of 

dolomite that crop out in Glenwood Canyon nearby. Other variations in porosity may indicate lithologic changes from sandstone to quartzite. Because vertical variations in hydrologic 

properties tend to approximate regional variations, one can 

anticipate that unit-averaged porosity could vary regionally 

from less than 5 to more than 20 percent.

Measured values of local-scale permeability in this hydrogeologic unit vary by five orders of magnitude. Values of local-scale 

permeability determined from five drill-stem tests in the Great 

Divide, Piceance, and Paradox Basins ranged from 0.003 to 

6.5 md, with a median value of 0.44 md. These values are typical 

of cemented sandstone with small to moderate permeability 

(fig. 19). In contrast, a drill-stem test on the Monument Upwarp 

indicated a local-scale permeability value of 42 md, typical of 

friable sandstone with moderate permeability. Regional trends 

cannot be extrapolated from the limited data.

HYDRAULIC CONDUCTIVITY AND TRANSMISSIVITY

On the basis of the available data, regional variations in 

hydraulic conductivity appear to be substantial. In the Great 

Divide, Piceance, and Paradox Basins, hydraulic-conductivity 

values determined from five drill-stem tests ranged from 

0.000007 to 0.016 ft/d, with a median value of 0.001 ft/d. In 

contrast to these small to moderate values, the hydraulic 

conductivity determined from a drill-stem test in an uplifted 

area, the Monument Upwarp, was 0.11 ft/d. The maximum 

hydraulic conductivity in uplifted areas is unknown, but it 

probably is at least as large as the hydraulic conductivity of 

similar strata in the underlying Uinta Mountain Group of 

Proterozoic age. Three pressure-injection tests of quartzite in 

the Uinta Mountain Group on the south flank of the Uinta 

Mountains by the Bureau of Reclamation (written commun., 

1983) indicated hydraulic-conductivity values ranging from 

0.29 to 0.40 ft/d. From an aquifer test nearby. Hood (1976, 

p. 63) estimated a hydraulic-conductivity value of 3 ft/d for 

the Uinta Mountain Group. If the values for the Proterozoic 

rocks are analogous, maximum values of hydraulic conductivity in the Flathead aquifer would appear to be between 0.1 

and 3 ft/d, in the range of friable sandstone with large 

hydraulic conductivity.

10,850

10,875 -

10,900 -

Sonic log 

Density log 

Neutron log

11,225

10 15 20 

POROSITY, IN PERCENT

FIGURE 26. Relation of geophysically determined porosity to 

depth below land surface in the Sawatch Quartzite near Eagle, 

Colorado.

The composite transmissivity of the Flathead aquifer probably ranges from 0.001 to 300 ft2/d. Hydraulic-conductivity 

values determined from drill-stem tests and the thickness of the 

aquifer at the sites of these tests indicate a composite transmissivity range of 0.0011 to 41 ft2/d (fig. 27). The previously 

mentioned aquifer test of the Uinta Mountain Group indicated a 

transmissivity of 190 ft/d. This latter value compares favorably 

with results of three flowing-well tests of the Flathead Sandstone 

on the faulted margin between the Bighorn Basin and the Bighorn 

Mountains (about 140 mi northeast of Pincdalc, Wyo.) that were
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS AQUIFER SYSTEM B47

,320 

L 250 -94

BOUNDARY OF

UPPER COLORADO'

RIVER BASIN

41

0.33

A-- 1-0.19

43 c c *

V207

190

"

0.38

0.0011

EXPLANATION

Type of test on which transmissivity 

value is based Number shown is 

transmissivity in feet squared per day

190

 Pumping test in Precambrian rocks

A 0.38

.94

Drill-stem test

Flowing-well test

/

 AREA EXCLUDED 

FROM STUDY

25 50 75 100 MILES

I I I I I

0 25 50 75 100 KILOMETERS

FIGURE 27. Transmissivity distribution in the Flathead aquifer in the Upper Colorado River Basin and vicinity.
B48 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

reported by Cooley (1985, p. 39). Transmissivity values determined from these tests ranged from 1 to 320 ft2/d. Similarly large 

values of transmissivity might be possible where the Flathead 

aquifer is present on the flanks of fault-bounded uplifts in the 

UCRB.

YIELDS FROM WELLS AND SPRINGS

Variations in well and spring discharges reflect the wide 

recorded range in the transmissivity of the Flathead aquifer. 

In 10 drill-stem tests throughout the UCRB, yields ranged 

from 0.60 to 26 gal/min, with a median value of 3.8 gal/min. 

Similarly, springs issuing from the Tapeats Sandstone in the 

Grand Canyon were estimated by Metzger (1961, p. 128) to 

have discharges of less than 1 to 5 gal/min, and a spring 

issuing from the Sawatch Quartzite in the Elk Mountains 

(SC14-85-22dda) was determined by the U.S. Geological 

Survey (unpublished) to have a discharge of 25 gal/min. In 

contrast to these small discharges, a spring issuing from the 

Flathead Sandstone in the Rawlins Uplift discharges at a rate 

of 100 gal/min (Berry, 1960, p. 51). Two warm springs in the 

Elk Mountains that might be issuing from either the Sawatch 

Quartzite or overlying formations of Cambrian to 

Mississippian age also have moderate discharges. Cement 

Creek Warm Spring (SC14-84-18cac) discharges at rates of 

60 to 80 gal/min from travertine deposits above the contact 

between Paleozoic rocks and Precambrian granitic rocks 

(Barrett and Pearl, 1977, p. 109) and may be related to a 

topographically and fault-controlled local flow system. 

Ranger Warm Spring (SC14-85-22dda) discharges at rates 

of 132 to possibly 250 gal/min (Barrett and Pearl, 1977, 

p. 112) and appears to be related to a fault that passes 

directly through the site of the spring. As indicated by flows 

from wells completed in the Flathead Sandstone in the 

Bighorn Basin (Cooley, 1985), discharges of 800 to 

3,000 gal/min might be possible from the aquifer on the 

faulted margins between basins and uplifts within the UCRB.

GROS VENTRE CONFINING UNIT

The Gros Ventre confining unit consists of the Ophir Shale, 

Bright Angel Shale and equivalents, Gros Ventre Formation, 

and the upper part of the Lodore Formation (table 1). Component geologic units are Early to Late Cambrian in age and 

become younger from west to east. Geologic units included in 

this hydrogeologic unit generally are considered to have negligible permeability. For example, Lines and Glass (1975) state 

that the Gros Ventre Formation in the Overthrust Belt consists 

of "poorly permeable rock." Hood and Danielson (1981, p. 16) 

indicate that the Ophir Shale in the Henry Mountains Basin has 

"very low permeability." According to Metzger (1961, p. 116), 

"***the most important hydrologic characteristic of the Bright 

Angel Shale in the Grand Canyon area is the retardation of the

downward percolation of ground water." Based on the 

consensus of opinion and limited data, this hydrogeologic unit 

was classified as a confining unit during this investigation.

THICKNESS AND LITHOLOGY

The Gros Ventre confining unit is 0 to 1,100 ft thick 

(fig. 28). Regionally, the confining unit is composed of claystone, siltstone, and sandy shale with subordinate interbeds of 

sandstone, limestone, and dolomite. The sandstone commonly 

is micaceous and glauconitic, but quartzitic layers are present 

near the base and margins of the confining unit. At the margins 

of depositional centers, sandstone and shale tend to be present 

in subequal amounts. Carbonate layers progressively increase in 

abundance toward depositional centers, where they can be as 

abundant as shale layers. From the Uinta Mountains south to the 

margins of the UCRB, component geologic units generally are 

overlain conformably to gradationally by Cambrian carbonate 

formations. North of the Uinta Mountains, however, the 

Gros Ventre Formation is overlain unconformably in most areas 

by carbonate and clastic rocks of Cambrian to Mississippian 

age.

PERMEABILITY AND HYDRAULIC CONDUCTIVITY

Because of its generally poor ability to supply water, the 

Gros Ventre confining unit virtually has been overlooked in 

hydrologic investigations. Consequently, little hydrologic data 

were obtained for this unit. No porosity information was found 

during this investigation. A drill-stem test of the Bright Angel 

Shale in the Paradox Basin (located at SLD 30-24-10da) indicated a local-scale permeability value of 0.18 md and a 

hydraulic-conductivity value of 0.00044 ft/d for an interval of 

interbedded sandstone, siltstone, and shale. In the western Uinta 

Mountains, pressure-injection tests of the Proterozoic Red Pine 

Shale, a unit similar to the Ophir Shale, may indicate upper 

limits of permeability and hydraulic conductivity for the Gros 

Ventre confining unit. A test of interbedded sandstone and siltstone in the Red Pine Shale indicated a local-scale permeability 

value of 10 md and a hydraulic-conductivity value of 0.025 ft/d; 

tests of fractured siltstone and shale indicated local-scale 

permeability values of 2.2 and 29 md and hydraulicconductivity values of 0.006 and 0.07 ft/d (Bureau of 

Reclamation, written commun., 1983). Available data indicate 

that intervals within the Gros Ventre confining unit that either 

are fractured or contain substantial interbeds of sandstone probably have moderate permeability and hydraulic conductivity. 

Intervals that are unfractured or composed mostly of shale probably have small permeability and hydraulic conductivity. The 

limited data do not permit estimates of transmissivity.

YIELDS FROM WELLS AND SPRINGS

Although the Gros Ventre confining unit generally retards 

ground-water movement, discharges to wells and springs may 

occur from the more permeable layers. A drill-stem test in the
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS AQUIFER SYSTEM B49

42

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

I ' ' .' ' Area where Gros Ventre confining unit 

is missing because of erosion or 

nondeposition

[ | Area where Gros Ventre confining unit 

consists of shale with less than 20 

percent sandstone and carbonate 

interbeds

Area where Gros Ventre confining unit 

consists of shale with subordinate 

sandstone interbeds

Area where Gros Ventre confining unit 

consists of shale with subordinate 

sandstone and carbonate interbeds

Area where Gros Ventre confining unit 

consists of shale with subordinate 

carbonate interbeds

 200 Line of equal thickness Interval is 

200 feet ice0/--.

AREA EXCLUDED 

FROM STUDY

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 28. Thickness and lithology of the Gros Ventre confining unit. 

(Modified from Geldon, in press, pi. 8.)
B50 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

Paradox Basin induced a flow of 8 gal/min from the Bright 

Angel Shale. Four springs issuing from this formation in the 

Grand Canyon each have estimated discharges of less than 

1 gal/min (Metzger, 1961, p. 128), and a spring issuing from the 

formation in the canyon of the Little Colorado River was estimated by McCulley (1985, p. 13) to have a discharge of 

6 gal/min. These data indicate that typical yields from this 

confining unit probably do not exceed 25 gal/min. However, a 

spring (SB26-113-07db) near La Barge, Wyo., that issues from 

a sandy lens in the Park Shale Member of the Gros Ventre 

Formation discharges at an estimated rate of about 900 gal/min 

(Lines and Glass, 1975). According to Bertagnolli (1941, 

p. 1743), the water issuing from this spring probably originates 

in the Bighorn Dolomite and is forced to the surface where the 

stratigraphic and hydraulic continuity of the Bighorn is interrupted by a fault. The issuance of the spring from the Gros 

Ventre Formation, therefore, is coincidental and does not result 

from lateral movement of water through the confining unit.

BIGHORN AQUIFER

The Bighorn aquifer consists of the Muav Limestone and 

equivalents, Maxfield Limestone, Lynch Dolomite, Gallatin 

Limestone, Dotsero Formation, Peerless Formation, Manitou 

Dolomite, Harding Sandstone, Fremont Limestone, and 

Bighorn Dolomite (table 1). Component geologic units generally are considered to be Middle Cambrian to Late Ordovician 

in age. Water availability from this hydrogeologic unit appears 

to depend mostly on fractures and solution openings. In the 

Bighorn Dolomite in the Overthrust Belt, for example, there are 

large volumes of poorly permeable rock, but water is readily 

discharged from solution-enlarged fractures (Lines and Glass, 

1975). In southeastern Utah, the Lynch Dolomite transmits 

water mostly through fractures and karst zones (Rush and 

others, 1982; Weir and others, 1983a). On the south rim of the 

Grand Canyon, the Muav Limestone is an aquifer because of the 

characteristic development of solution channels (Metzger, 

1961, p. 117). The fractures and solution channels that make 

this hydrogeologic unit an aquifer in and near uplifted areas 

probably are not well developed in structural basins, and, in 

these latter areas, the unit may be too intact to transmit much 

water. Shale layers, which are abundant locally, also would 

impede ground-water movement. Because of these regional 

variations in water-supply capability, this hydrogeologic unit 

can be expected to function as an aquifer subregionally in the 

UCRB.

THICKNESS AND LITHOLOGY

The Bighorn aquifer is 0 to more than 3,000 ft thick 

(fig. 29). Regionally, the aquifer consists of limestone and dolomite with subordinate shale layers and generally less than 

5 percent sandstone layers. The Cambrian carbonate rocks 

within the Bighorn aquifer typically are glauconitic and oolitic

and contain flat-pebble or edgewise conglomerate layers; in the 

Four Corners area, the rocks are shaly. The Ordovician 

carbonate rocks within the aquifer can be granular, crystalline, 

or fine grained, and the Manitou Dolomite tends to be siliceous. 

Shale and sandstone layers account for less than 20 percent of 

the aquifer and are most abundant toward its bottom and 

margins, where component geologic units grade into other 

Cambrian formations. In all areas, the geologic units that 

compose the Bighorn aquifer are overlain unconformably by 

Devonian and Mississippian rocks.

POROSITY AND PERMEABILITY

On the basis of samples mostly from the Muav Limestone in 

the Four Corners area, porosity in the Bighorn aquifer is estimated to range from 0.1 to 13 percent. In 46 samples of dolomite from three borehole intervals in the Muav Limestone, the 

porosity ranged from 0.1 to about 13 percent, with a median 

value of 1.8 percent (table 6). In a borehole near Big Piney, 

Wyo., the Bighorn Dolomite exhibited a range in geophysically 

determined porosity of 0.6 to 9.3 percent and a median porosity 

of 5.0 percent (fig. 30). The unit-averaged porosity at the four 

data sites, where data is obtained, is estimated to range from 1.5 

to 5.0 percent.

The available data indicate that the Bighorn aquifer characteristically exhibits moderate permeability. In 56 samples of 

dolomite and sandstone from the Muav Limestone, pore-scale 

permeability ranged from less than 0.01 to 157 md, with median 

values of less than 0.01 md for the dolomite and 0.85 md for the 

sandstone (table 6). For the dolomite, there appears to be a crude 

relation between porosity and pore-scale permeability (fig. 31). 

Using this relation (for which an equation is given in table 3), 

the Bighorn Dolomite near Big Piney, Wyo., was estimated to 

have a unit-averaged pore-scale permeability value of 0.13 md, 

which, according to equation 8, is equivalent to a local-scale 

permeability value of 0.68 md. In comparison, 10 drill-stem 

tests of beds equivalent to the Muav Limestone and Lynch 

Dolomite in southeastern Utah and northeastern Arizona indicated values of local-scale permeability ranging from 0.029 to 

23 md; the median of these values was 2.9 md. The available 

data are insufficient for extrapolation of regional trends in 

permeability.

HYDRAULIC CONDUCTIVITY AND TRANSMISSIVITY

The permeability data discussed in the previous section are 

equivalent to a range in hydraulic conductivity of 0.000071 to 

0.056 ft/d and a median hydraulic conductivity of 0.007 ft/d. As 

shown in figure 29, unit-averaged hydraulic conductivity in the 

Bighorn aquifer in the Four Corners area ranges from 0.00075 

to 0.056 ft/d, and near Big Piney, Wyo., the unit-averaged 

hydraulic conductivity is 0.0017 ft/d.

On the basis of the available values of unit-averaged 

hydraulic conductivity and the thickness of the Bighorn aquifer 

at sites where these hydraulic-conductivity values were determined, the range in composite transmissivity for the aquifer is
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS AQUIFER SYSTEM B5I

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

[;.'- ' ] Area where Bighorn aquifer is missing 

because of erosion or nondeposition

Area where Bighorn aquifer consists 

of limestone and dolomite with less 

than 20 percent shale and sandstone 

interbeds

Area where Bighorn aquifer consists 

of limestone and dolomite with 

subordinate shale interbeds

____ Area where Bighorn aquifer consists 

of limestone and dolomite with 

subordinate sandstone and shale 

interbeds

 200 Line of equal thickness Interval is

200 feet

Data sites Number shown is estimated 

unit-averaged hydraulic conductivity, in 

feet per day 

0.0017

 Site at which estimate is based on median 

of geophysically determined porosity 

values in a borehole interval

0.056

 Site al which estimate is based on mean 

of laboratory-determined permeability 

values in a borehole interval 

0.013

A Site at which estimate is based on

permeability determined by one or more 

drill-stem tests

 AREA EXCLUDED 

FROM STUDY

25

I

50

I

100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 29. Thickness, lithology, and unit-averaged hydraulic conductivity of the Bighorn aquifer.

(Modified from Geldon, in press, pi. 9.)
B52 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

TABLE 6. Porosity and pore-scale permeability statistics for the Bighorn aquifer

[In this and all subsequent compilations of porosity and permeability statistics, the number of observations fora rock type does not equal the sum of observations 

for subcategories because (1) many samples of a rock type were not classifiable into a subcategory; and (2) many samples were classifiable into more than one 

subcategory. For example, a sample described as "shaly, fine-grained sandstone" could be included in the statistical analyses of sandstone, shaly sandstone, and 

fine-grained sandstone. Samples that were described as combinations of mutually exclusive rock types, such as "limestone and shale" were rejected for the statistical analysis of either rock type. Samples that were described as combinations of mutually exclusive textures, such as "crystalline to sucrose limestone," were 

included in the statistical analysis for the rock type but were rejected for the statistical analysis of either texture; <, less than]

Rock type

Dolomite

Shaly

Vuggy

Medium-grained

All

Sandstone

Minimum

O.I

1.7

7.0

0.1

2.5

Porosity 

(percent)

Maximum

8.1

12.6

12.6

12.6

8.2

Median

2.1

3.5

11

1.8

4.6

Number of 

observations

20

9

4

46

10

Pore-scale permeability 

(millidarcies)

Minimum

<0.01

.01

.10

<.01

.01

Maximum

157

157

157

157

5.5

Median

<O.OI

1.6

3.6

<01

.85

Number of 

observations

20

9

4

46

10

estimated to be at least 0.10 to 6 fr/d. Composite transmissivity 

values probably are larger than 6 ft2/d in uplifted areas where 

the Bighorn aquifer is faulted and yields large quantities of 

water to springs (see discussion in next section). Composite 

transmissivity values probably are smaller than minimum estimates where the Bighorn aquifer is sparsely fractured (in the 

interiors of structural basins) or contains abundant shale 

interbeds.

YIELDS FROM WELLS AND SPRINGS

Yields to most wells and springs from the Bighorn 

aquifer are less than 500 gal/min. In 13 drill-stem tests of the 

Muav Limestone, Lynch Dolomite, and Bighorn Dolomite, 

discharges ranged from 3.0 to 41 gal/min, with a median 

value of 7.5 gal/min. Numerous springs and seeps issuing 

from the Muav Limestone in the Grand Canyon have 

discharges ranging from less than 1 to 10 gal/min, and 

collectively, the springs at Hermit Creek and Indian Gardens 

discharge at rates of 200 to 300 gal/min (Metzger, 1961; 

Cooley, 1976). In the Overthrust Belt, three springs issuing 

from the Bighorn Dolomite have discharges of 125 to 

450 gal/min. These data indicate that under most circumstances, yields from the Bighorn aquifer are likely to be in 

the small to moderate range. Near faults, however, large 

discharges may be possible. As previously mentioned, a 

spring near La Barge, Wyo., with a discharge of about 

900 gal/min probably is caused by water traveling along a 

fault from the Bighorn Dolomite to a permeable bed in the 

Gros Ventre Formation. Another spring in the Overthrust 

Belt (SB34-118-26aad) discharges from the Bighorn 

Dolomite at a rate of 3,200 gal/min (Lines and Glass, 1975). 

The location of this spring, too, is controlled by a fault, and 

some of the flow probably is from the Lodgepole and 

Mission Canyon Limestones of the overlying RedwallLeadville zone of the Madison aquifer.

ELBERT-PARTING CONFINING UNIT

The Elbert-Parting confining unit consists of the Darby, 

Parting, Elbert, and Temple Butte Formations, and the 

Cottonwood Canyon Member of the Lodgepole and Madison 

Limestones (table 1), which are Late Devonian to Early 

Mississippian in age. The confining unit is so heterogeneous 

that its capability to supply water mostly depends on the rock 

types that are present in an area and, secondarily, on whether 

carbonate rocks contain solution channels and(or) whether the 

rocks, in general, are fractured. Large parts of the Elbert 

Formation, for example, consist of negligibly permeable rock; 

but in the Four Corners area, sandstone and carbonate beds in 

the lower part of the formation produce water (INTERA 

Environmental Consultants, Inc., 1984). The Darby Formation 

does not transmit water readily to wells, but near faults in the 

Overthrust Belt, springs issue from the formation (Lines and 

Glass, 1975). Similarly, the Parting Formation generally is not 

known to transmit water, but in a well that was drilled at the 

fault-bounded southern end of the Park Range (SC02-84-03), 

the flow from the well apparently increased when fractured 

quartzite in the lower part of the Parting Formation was penetrated (unpublished consultant's report furnished by the 

Colorado Division of Water Resources, written commun., 

1984). Regionally, the hydrogeologic unit impedes flow in more 

places than it transmits water and, therefore, it was classified as 

a confining unit in this investigation.

THICKNESS AND LITHOLOGY

The thickness of the Elbert-Parting confining unit ranges 

from 0 to more than 1,000 ft (fig. 32). Regionally, the 

confining unit is characterized by highly variable proportions 

of limestone, dolomite, sandstone, quartzite, shale, and anhydrite. Generally, the Darby, Elbert, and Temple Butte 

Formations gain carbonate rocks at the expense of clastic
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS AQUIFER SYSTEM B53

layers westward across the UCRB, and the Parting Formation 

becomes more carbonaceous toward the center of its depositional area. In most areas, carbonate rocks comprise at least 

50 percent of the confining unit. Shale layers generally 

account for at least one-third of the confining unit and locally 

exceed carbonate layers in abundance. Sandstone and 

quartzite layers rarely compose more than one-third of the 

confining unit, but they predominate on the southeastern edge 

of the Darby-Cottonwood Canyon depositional area, on the 

northeastern edge of the Parting depositional area, and at the 

base of the Elbert Formation. Anhydrite layers account for as 

much as 10 percent of the confining unit in the Overthrust Belt 

west of Kemmerer, Wyo. Component geologic units in

15,700

15,725

15,975 -

16,000

BOREHOLE 

SB29-114-08

Sonic log 

Density log _ 

Neutron log

POROSITY, IN PERCENT

FIGURE 30. Relation of geophysically determined porosity to 

depth below land surface in the Bighorn Dolomite near Big 

Pincy, Wyoming.

1,000

100

in

LJ

o tr.

10

CO

<

0.1

0.01

0.001

5 10 

POROSITY, IN PERCENT

15

FIGURE 31. Relation of porosity to pore-scale permeability 

in dolomite samples from the Muav Limestone.

Wyoming and the Grand Canyon area are overlain unconformably by Mississippian carbonates, whereas the Elbert and 

Parting Formations generally are overlain conformably by 

formations of Devonian to Mississippian age.

POROSITY AND PERMEABILITY

The only porosity data found for the Elbert-Parting 

confining unit were for the Elbert Formation, but on the basis 

of the lithologic similarity of the Elbert Formation to the 

other component geologic units, it is presumed that these data 

are representative of the entire confining unit. The available 

data indicate a porosity range of 0.3 to about 12 percent for 

rock types within the confining unit (fig. 33 and table 7). 

Sandstone, with a median porosity of 6.1 percent, is more 

porous than dolomite, with a median porosity of 1.9 percent 

(table 7). On the basis of relatively few analyses, shale and 

quartzite both appear to have median porosity values of about 

1 percent. On the basis of lithologic composition and median 

porosity values for the common rock types that are present, 

unit-averaged porosity for the Elbert-Parting confining unit is 

estimated to range regionally from less than 2 to about 

5 percent (fig. 34).
B54 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

-^ ."-"l- ' " *." ." -" *-* '.* '.* * " '-" '-" *-" 'N

:.-.:: . ': : -l::}.: :-V: :-V: '.:: >$: ::-.: I

EXPLANATION

Area where Elbert-Parting confining unit 

is missing because of erosion or 

nondeposition

Area where Elbert-Parting confining unit 

consists of limestone, dolomite, and 

shale with less than 20 percent 

sandstone and quartzite interbeds

Area where Elbert-Parting confining unit 

consists of limestone, dolomite, shale, 

sandstone, and quartzite

Area where Elbert-Parting confining unit 

consists of sandstone, quartzite, and 

shale with less than 25 percent 

carbonate interbeds

 200 Line of equal thickness Interval, in feet, 

is variable

AREA EXCLUDED 

FROM STUDY

25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 32. Thickness and lithology of the Elbert-Parting confining unit. 

(Modified from Geldon, in press, pi. 10.)
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS AQUIFER SYSTEM B55

35

30

25

>- 20

a

15

10

\ I I I I 

DOLOMITE

_L J_

5 6 7 8 9 10 

POROSITY, IN PERCENT

11 12 13 14 15

20

15 -

g10

1 I I T~ 

SANDSTONE

0 1 5 6 7 8 9 10 11 12 13 14 15 

POROSITY, IN PERCENT

FIGURE 33. Frequency distribution of porosity in samples 

of dolomite and sandstone from the Elbert Formation.

Interpretations of permeability in the Elbert-Parting 

confining unit also are based entirely on information for the 

Elbert Formation. These data indicate that pore-scale permeability ranged from less than 0.01 to 179 md, with median 

values of 0.42 md for sandstone, 0.02 md for quartzite, and 

less than 0.01 md for dolomite and shale (table 7 and fig. 35). 

Pore-scale permeability is crudely related to porosity in sandstone samples (fig. 36) but is not related to porosity in dolomite samples (table 3). In 30 drill-stem tests, local-scale 

permeability ranged from 0.021 to 95 md, with median values 

of 2.3 md in intervals without shale and 1.2 md in intervals 

with shale. Together, the laboratory and field data indicate 

that the confining unit has small to moderate permeability, 

which is highly dependent on proportions of sandstone, dolomite, and shale.

HYDRAULIC CONDUCTIVITY AND TRANSMISS1VITY

The permeability data discussed in the previous section are 

equivalent to a range in hydraulic conductivity of 0.000051 to 

0.25 ft/d (fig. 37). The median of these values is 0.004 ft/d and 

is twice as large for intervals without shale (0.006 ft/d) than for 

intervals with shale (0.003 ft/d). Unit-averaged hydraulic 

conductivity of the Elbert Formation, based on tests of lithologically representative intervals, is estimated in the Four Corners 

area to range from 0.00005 to 0.25 ft/d, increasing from basins 

to uplifted areas (fig. 38).

The composite transmissivity of the Elbert Formation, 

based on areal distributions of unit-averaged hydraulic conductivity and thickness of the formation, is estimated to range from 

0.008 to 200 ft2/d (fig. 39). The transmissivity of this formation 

probably is as large as that of any other component geologic unit 

in the Elbert-Parting confining unit because the Elbert 

Formation is the most consistently water bearing of these 

geologic units. Therefore, although the minimum values of 

composite transmissivity for the Elbert-Parting confining unit 

may be less than that for the Elbert Formation, it is not likely 

that the confining unit is more transmissive where it is 

composed of geologic units other than the Elbert Formation, 

except possibly along thrust faults in the Overthrust Belt. Tentatively, the range in composite transmissivity for this confining 

unit is estimated to be that of the Elbert Formation.

YIELDS FROM WELLS AND SPRINGS

Yields from the Elbert-Parting confining unit typically are 

negligible to moderate. In the Four Corners area, many drillstem tests produced negligible quantities of water, but 29 tests 

produced discharges ranging from 1.5 to 58 gal/min. The 

median value for these tests was 8.5 gal/min. In the Overthrust 

Belt, one of three springs known to be issuing from the Darby 

Formation (SB33-117-24b) has a discharge of 40 gal/min 

(Lines and Glass, 1975), which is consistent with discharges 

from the Elbert Formation. However, two springs in the
B56 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

TABLE 7. Porosity and pore-scale permeability statistics for the Elbert-Parting confining unit

[<, less than]

Rock type

Dolomite

Crystalline

Shaly

Sandy

All

Sandstone

Glauconitic

Shaly

Quartzitic or dolomitic

Fine-grained

Medium-grained

Coarse-grained

All

Quartzite

Shale

Minimum

0.5

.4

.4

.4

2.0

.8

1.1

.8

1.1

2.7

.8

1.0

.3

Porosity 

(percent)

Maximum

7.4

5.2

3.7

7.4

6.5

8.5

11.9

12.2

10.6

8.4

12.2

4.1

2.5

Median

1.7

2.0

2.2

1.9

5.0

5.3

6.9

6.5

5.7

5.3

6.1

1.2

1.4

Number of 

observations

56

54

35

92

7

23

36

83

18

12

121

5

5

Pore-scale permeability 

(millidarcies)

Minimum Maximum

<0.01 7.0

<.01 .36

<.01 <.01

<.01 7.0

<.01

<.01 .04

<.01 62

<.01 24

<.01 179

<.01 7.0

<.01 55

<.01 179

<.01 .11

<.01 .05

Median

<0.01

<.01

<.01

<.01

.01

.10

1.0

.81

.32

1.6

.42

.02

<.01

Number of 

observations

56

54

35

92

7

23

36

83

18

12

121

5

5

Overthrust Belt (SB38-115-03bca and SB38-115-03bcd) have 

discharges of 900 and 1,100 gal/min (Lines and Glass, 1975). 

These two large springs issue in a zone of thrust faults and could 

be outlets for water traveling along fault planes from the 

Lodgepole and Mission Canyon Limestones. As indicated in 

figure 40, the two large springs clearly are outliers and, consequently, they are not considered representative of the waterbearing properties of the Elbert-Parting confining unit.

REDWALL-LEADVILLE ZONE OF 

THE MADISON AQUIFER

The Redwall-Leadville zone of the Madison aquifer consists 

of the Dyer Dolomite, Ouray Limestone, Oilman Sandstone, 

Leadville Limestone, and Redwall Limestone; the main bodies of 

the Lodgepole and Madison Limestones; and the lower part of the 

Mission Canyon Limestone (table 1). Component geologic units 

mostly are Late Devonian to Late Mississippian in age. Although 

pore-scale permeability in the Redwall-Leadville zone is relatively small, the zone transmits water through a system of interconnected solution channels and fractures nearly everywhere that 

it occurs. Examples include the Madison Limestone in the 

Rawlins Uplift (Berry, 1960) and Uinta Mountains (Hood, 1976); 

the Leadville Limestone in the White River Plateau (Teller and 

Welder, 1983), and the Redwall Limestone in the San Rafael 

Swell (Hood and Patterson, 1984) and Grand Canyon (Metzger, 

1961). The relatively large and omnipresent permeability of the 

Redwall-Leadville zone, according to Lines and Glass (1975), 

exists because some of the solution channels in the aquifer developed during Pennsylvanian uplift of the region. Older carbonate

units do not possess these ancient solution features and have solution permeability only near modern uplifted areas. In contrast, the 

Redwall-Leadville zone, because of its relict solution channels, 

can be permeable even where it is deeply buried. Indeed, the 

Redwall-Leadville zone in the Paradox Basin is more permeable 

than all other Paleozoic and Mesozoic rocks except some Jurassic 

sandstone formations (Rush and others, 1982; Weir and others, 

1983a; Whitfield and others, 1983).

The importance of fracturing and solution channels to 

flow through the Redwall-Leadville zone is demonstrated by 

interception of streamflow at outcrops of the Madison 

Limestone. In Sinks Canyon on the north flank of the Wind 

River Mountains, the entire flow of the Middle Popo Agie 

River disappears into a cavern in the Madison Limestone, 

emerging about half a mile downstream as springs from the 

Tensleep Sandstone (Whitcomb and Lowry, 1968). On the 

south flank of the Uinta Mountains, the entire flows of Big 

Brush Creek, Pole Creek, and the three branches of the Dry 

Fork of Ashley Creek disappear into caves or sinkholes in the 

Madison Limestone. Springs issuing from the Madison 

Limestone, Pennsylvanian and Permian Weber Sandstone, 

Permian Park City Formation, and Triassic Moenkopi 

Formation downstream from these sinks have been traced by 

dye tests to the sinks (Maxwell and others, 1971). Springs 

issuing in Big Brush Creek and Pole Creek are traceable to 

sinks directly upstream. However, water disappearing into 

sinks on the Dry Fork of Ashley Creek emerges as springs 

not only in the Dry Fork but also in Deep Creek and the main 

fork of Ashley Creek (see figs. 1 and 2 of Maxwell and 

others, 1971). The tracer tests confirmed long-held
HYDROLOGIC PROPERTIES OF THE FOLR CORNERS AQUIFER SYSTEM B57

110

43--

42"

EXPLANATION

V

Pinednle \ ° Lander

109 108'

BOUNDARY OF

UPPER COLORADO'

RIVER BASIN

[ '/'. ' '.' j Area where Elbert-Parting confining unit 

is missing because of erosion or 

nondeposition

 2 Line of equal estimated unit-averaged 

porosity Location is approximate. 

Interval is 1 percent 

3.0 

 Site of a borehole lithologically

similar to the entire Elbert-Parting 

confining unit in the area, from which 

samples were obtained for porosity 

measurements Number is the mean 

of porosity values from the interval

AREA EXCLUDED 

FROM STUDY

25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 34. Estimated distribution of unit-averaged porosity in the Elbert-Parting confining unit.
B58 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

o.c

100 

80 

60

40

20

n

PERMEABILITY, IN MILLIDARCIES 

01 0.1 0.32 1.0 3.2 10

-

-

1 

DOLOMITE

-

-

1 ______ | 

-3.0 -1.0 -0.5 0 0.5 1.0 

LOG (BASE 10) OF PERMEABILITY, IN MILLIDARCIES

0.( 

50

40 

30 

20 

10 

n

PERMEABILITY, IN MILLIDARCIES 

)01 0.1 0.32 1.0 3.2 10 32 100 320 1,000

-

i 

SANDSTONE

-

-3.0 -1.0 -0.5 0 0.5 1.0 1.5 2.0 2.5 

LOG (BASE 10) OF PERMEABILITY, IN MILLIDARCIES

3.0

FIGURE 35. Frequency distribution of pore-scale permeability in 

samples of dolomite and sandstone from the Elbert Formation.

hypotheses that a well-developed system of interconnected 

fractures and solution channels exists in the Madison 

Limestone and, by extension, other limestone formations 

comprising the Redwall-Leadville zone. Therefore, the 

Redwall-Leadville zone can be expected to function as an 

aquifer throughout the UCRB.

THICKNESS AND L1THOLOGY

The thickness of the Redwall-Leadville zone ranges from 0 

to 2,500 ft (fig. 41). Limestone, dolomite, and bedded and 

nodular chert compose more than 95 percent of the RedwallLeadville zone, with the proportion of limestone to dolomite 

decreasing away from uplifted areas. Regionally, careful tracing 

of stratigraphic markers between outcrops and boreholes indicates that limestone beds grade laterally into dolomite beds, 

such that neither the proportions nor sequence of limestone and 

dolomite can be used to establish contacts between Devonian 

and Mississippian formations. Sandstone and shale, 

concentrated in the interval between Devonian and 

Mississippian carbonate rocks and at the top of the 

Mississippian sequence, account for 5 to 10 percent of the 

Redwall-Leadville zone in areas interpreted to have been sites 

of shallow marine or intermittently subaerial deposition. The 

upper surface of the Redwall-Leadville zone is an unconformity 

that progressively truncates older rocks from west to east across 

the region. Shale layers, channel sandstone, or a rubble of 

carbonate and chert blocks in a matrix of shale or sandstone 

generally is present above the unconformity.

POROSITY AND PERMEABILITY

The porosity of carbonate rocks in the Redwall-Leadville 

zone depends on both composition and texture. Limestone 

porosity ranged from 0.3 to 15 percent, with a median value of 

1.7 percent (fig. 42). Dolomite, on the average, is nearly four 

times more porous than limestone. Dolomite porosity ranged 

from 0.3 to about 22 percent, with a median value of 6.5 percent 

(fig. 42). In all types of limestone, median porosity ranged from 

about 1 to 3 percent (table 8). Dolomite porosity clearly is larger 

in varieties with a tendency for solution cavities to develop 

around inclusions, such as cherty, anhydritic, or vuggy dolomite, than in laminar varieties, such as shaly dolomite (table 8). 

On the other hand, a study by Thayer (1983) of the Madison 

Limestone in and near the Powder River Basin of Montana and 

Wyoming found that porosity and pore-scale permeability in 

this formation can be reduced substantially by secondary 

anhydrite, chert, and calcite in pores and fractures. Thayer 

(1983, fig. 24) also found that porosity in the Madison 

Limestone is independent of sampling depth, except possibly at 

depths of 3,000 ft or less. Because of lithologic variation and, 

possibly, variations in fracture development, porosity in the 

Redwall-Leadville zone of the Madison aquifer in the UCRB 

also shows no systematic variation with depth (for example, see
HYDROUOGIC PROPERTIES OF THE FOUR CORNERS AQUIFER SYSTEM B59

1,000

100

Lu

O

IT

g

10

CQ

< 

LU

E 0.1

D_

0.01

0.001

% *

 

 - . » *

5 10 

POROSITY, IN PERCENT

15

FIGURE 36. Relation of porosity to pore-scale permeability 

in sandstone samples from the Elbert Formation.

fig. 43). On the basis of limestone to dolomite ratios, median 

values of porosity for limestone and dolomite, and scattered 

measurements, unit-averaged porosity in the study area is 

estimated to range regionally from less than 1 to 1 1 percent 

(pi. 2).

Most samples of limestone and dolomite in this hydrogeologic unit, regardless of texture, have little pore-scale permeability, although some samples can be very permeable. The 

pore-scale permeability of limestone ranges from less than 0.01 

to 940 md, with a median value of less than 0.01 md. The porescale permeability of dolomite ranged from less than 0.01 to 

673 md, with a median value of 0.10 md. Median values of 

pore-scale permeability were less than 0.01 md for all varieties 

of limestone, whereas several varieties of dolomite, including 

anhydride or chcrty, crystalline, and vuggy dolomite, had 

median values of pore-scale permeability of 0.01 md or larger 

(table 8). On the average, dolomite appears to be at least 

10 times more permeable than limestone at pore scale.

In neither dolomite nor limestone does there appear to be 

any correlation between porosity and pore-scale permeability 

(fig. 44). This is attributed to the influences of secondary

mineralization, fracturing, and solution on permeability. 

Carbonate rocks with large porosity and small pore-scale 

permeability probably have large unconnected vugs or may 

have pores partially filled with secondary calcite, silica, or 

anhydrite. Carbonate rocks with small porosity and relatively 

large pore-scale permeability probably contain fractures (see 

Thaycr, 1983, p. 19-20).

Permeability values determined from field tests span the 

range from unfractured carbonate rocks with small permeability 

to fractured rocks with large permeability. In 136 drill-stem 

tests, local-scale permeability values ranged from 0.02 to 

1,800 md, with a median value of 5.6 md. Local-scale permeability values of limestone ranged from 0.30 to 42 md, with a 

median value of 2.9 md. Local-scale permeability values of 

dolomite ranged from 0.027 to 540 md, with a median value of 

12 md. Therefore, both the laboratory and drill-stem-test data 

indicate that dolomite in this hydrogeologic unit is more permeable than limestone.

HYDRAULIC CONDUCTIVITY, TRANSMISSIVITY, 

AND STORATIVITY

Hydraulic conductivity in intervals of the RedwallLeadville zone ranges from small to large. In 172 tests of 

various kinds (pi. 2), the hydraulic conductivity of limestone 

and dolomite intervals ranged from 0.00005 to 200 ft/d, with a 

median value of 0.023 ft/d. Median values for limestone and 

dolomite were not significantly different in these tests (fig. 45). 

Pressure-injection tests by the Bureau of Reclamation at a 

damsite in the Uinta Mountains indicate that the hydraulic

HYDRAULIC CONDUCTIVITY, IN FEET PER DAY 

0.000032 0.0001 0.00032 0.001 0.0032 0.01 0.032 0.1 0.32

u.u

7.5

2.5

0 

-4 5 -4 0 -3 5 -3 0 -2 5 -2.0 -1 .5 -1 .0 -0

LOG (BASE 10) OF HYDRAULIC CONDUCTIVITY, 

IN FEET PER DAY

FIGURE 37. Frequency distribution of hydraulic conductivity 

in the Elbert Formation.
B60 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

I____| Uplifted area

UP Uncompahgre Plateau

SM San Juan Mountains

DC -Defiance Plateau and Chuska

Mountains

MU Monument upwarp 

SC San Rafael Swell, Circle Cliffs

uplift, and Capitol Reef fold

and fault belt

Structural basin

PB Paiadox Basin

BT Blanding Basin and Tyende saddle

FP Four Corners platform

BM Black Mesa Basin

HB Henry Mountains Basin

 0.0 1 Line of equal unit-average hydraulic

conductivity Location is approximate. 

Interval, in feet per day, is variable

 Boundary of uplifted area or structural 

basin

Data sites

Hydraulic conductivity calculated from 

permeability determined by one or 

more drill-stem tests

Hydraulic conductivity calculated from the 

mean of laboratory-determined 

permeability values in a borehole 

interval

 AREA EXCLUDED 

FROM STUDY

25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 38. Estimated areal distribution of unit-averaged hydraulic conductivity in the Elbert Formation.
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS AQUIFER SYSTEM B61

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

10 Line of equal composite

transmissivity Location is 

approximate. Interval, in feet 

squared per day, is variable

 AREA EXCLUDED 

FROM STUDY

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 39. Estimated distribution of composite transmissivity in the Elbert Formation.
B62 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

YIELD, IN GALLONS PER MINUTE 

0.10 0.16 0.25 0.40 0.63 1.0 1.6 2.5 4.0 6.3 10 16 25 40 63 100 160 250 400 630 1,000 1,600 I T

§4 

O

"I I T

-1.0 -0.8 -0.6 -0.4 -0.2 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 

LOG (BASE 10) OF YIELD, IN GALLONS PER MINUTE

2.2 2.4 2.6 2.8 3.0 3.2

FIGURE 40. Frequency distribution of yields from the Elbert-Parting confining unit.

conductivity of carbonate rocks appears to be related more to 

bedding thickness, joint spacing, brecciation, openness of 

fractures, vugginess, and the presence of chert nodules and beds 

than to composition (fig. 46). Reflecting the greater amount of 

open fractures and solution channels in uplifted areas, unitaveraged hydraulic conductivity increased from 0.00005 ft/d in 

structural basins to 200 ft/d in uplifted areas (pi. 2).

Aquifer tests at Ouray, Colo., indicate how dependent transmissivity in the Redwall-Leadville zone is on fractures and 

solution channels. Drawdown with time caused by four 

successive increments of discharge in a step-drawdown 

pumping test of well OX-3 (fig. 5) indicated values of transmissivity ranging from 130 to 280 ft2/d, with an average value of 

about 200 ft2/d. At completion, the flow into well OX-3 was 

measured as 120 gal/min. Located just 245 ft from well OX-3, 

well OX-5 (NMB44-07-31 cbd4) flowed at a rate of only 

2 gal/min. As illustrated in figure 47, head recovery in 

well OX-5 during an airlift test of the Leadville Limestone on 

July 5, 1987, indicated the following:

T =

= Tt/rc = 1.0

r 2S

a = = 0.001

1.Ox 0.29ft

(23)

(24)

3,600 sec x 1 day/86,400 sec

= 2ft2/d

where 

T

t

rf.

S =

transmissivity, in feet squared per day; 

time since slug removed, in seconds; 

radius of casing, in feet; 

effective well radius, in feet; and 

storativity, dimensionless.
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS AQUIFER SYSTEM B63

BOUNDARY OF 

UPPER COLORADO 

RIVER BASIN

2,500

EXPLANATION

[/.' '. '.' '. | Area where Redwall-Leadville zone is 

missing because of erosion or 

nondeposition

Area where Redwall-Leadville zone 

consists of limestone with subordinate 

dolomite and less than 10 percent 

shale and sandstone interbeds

Area where Redwall-Leadville zone 

consists of dolomite with subordinate 

limestone and less than 10 percent 

shale and sandstone interbeds

 200 Line of equal thickness Interval is 200 

feet, except along western edge of study 

area in Wyoming, where interval is 

variable

AREA EXCLUDED 

FROM STUDY

25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 41. Thickness and lithology of the Redwall-Leadville zone of the Madison aquifer. 

(Modified from Geldon, in press, pi. 11.)
FREQUENCY FREQUENCY

*n

o c

50

fl) D-

- = ft05

aD.

o

 <

z -1"o _> m fsjo

OZ -

s

-o

ca50

,

V:mr

r-a-o en 50n Oc73 

> D 

O 

73< tn 73CDm X

n

rDz 

o

Hm

C 

> ZCD
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS AQUFER SYSTEM B65

TABLE 8. Porositv and pore-scale permeability statistics for the Redwall-Leadville zone of the Madison aquifer

[<. lessthan|

Rock type

Limestone

Oolitic

Shaly

Fossiliferous

Anhydritic or cherty

Algal

Crystalline

Sucrosic

All

Dolomite

Shaly

Fossiliferous

Anhydritic or cherty

Vuggy

Fine-grained

Crystalline

All

Shale

Sandstone

Chert 1

Anhydrite'

Minimum

1.2

.3

.4

1.2

1.0

.3

1.4

.3

1.6

3.2

.8

2.0

.7

.5

.3

1.5

.9

.6

.3

Porosity 

(percent)

Maximum

3.1

4.1

5.1

3.9

2.8

10.0

3.2

15.0

10.0

15.9

17.1

15.4

4.9

21.3

21.6

4.0

21

19

1.3

Median

2.4

.8

2.6

1.9

1.6

1.2

1.8

1.7

3.3

5.7

8.3

10.2

1.9

7.8

6.5

2.8

13

11

.6

Number of 

observations

10

48

149

10

16

243

8

513

49

8

112

17

8

175

435

2

6

4

10

Pore-scale permeability 

(millidarcies)

Minimum Maximum Median

<o.oi <o.oi <o.ni

<.OI 20.0 <.OI

<.OI 3.1 <.01

<.01 356 <.01

<.01 389 <.OI

<.01 940 <.01

<.01 <.OI <.OI

<.01 940 <.01

<.01 5.9 <.01

<.01 24 <.01

<.01 13.3 <.01

<.01 13.3 2.4

<.01 <.01 <.01

<.01 335 .05

<.()! 673 .10

< ,

.03 1 19 24

.28 .72 .45

.01 .06 .03

Number of 

observations

10

48

149

10

16

244

8

513

49

8

112

17

8

175

435

2

6

3

4

Samples from the Powder River Basin and vicinity in northeastern Wyoming and south-central Montana (from Thayer, 1983. p. 7). Values in median columns 

are the means of analyses; the median values were not reported.

The substantial differences in transmissivity and yield determined in the 245 feet between wells OX-3 and OX-5 indicate 

that the Leadville Limestone at Ouray is extremely heterogeneous. Hydrologic and geologic reports prepared by consultants 

for the City of Ouray (David Vince, City of Ouray, written 

commun., 1988) indicate that this heterogeneity probably is 

related to a site's position with respect to the Ouray or Portland 

Creek faults, splays from these faults, or fracture zones related 

to the faulting. One consultant concluded that all 12 of the hot 

and warm springs mapped at Ouray issue from faults, joints, or 

bedding planes, and none appear to be related to folds, breccia 

zones, or formational contacts.

The maximum value of transmissivity for the RedwallLeadville zone of the Madison aquifer in the UCRB was determined during the RASA study from a flowing-well test of the 

Leadville Limestone at Glenwood Springs, Colo. (see Geldon, 

1989c, for test description and interpretation). This test was 

done in November 1984. In the test area, the Redwall-Leadville

zone consists of the Dyer Dolomite and Leadville Limestone, 

which are transected by faults and, consequently, are highly 

fractured. Caves in the Leadville Limestone, some of which 

contain hot water and steam, are visible near the test site. 

During the aquifer test, a geothermal well (SC06-89-09bba) 

was allowed to flow for 4 days, discharging a volume of 

10.5 million gallons of water. This discharge decreased head in 

the production well by about 8 ft, lowered head in an observation well about 0.8 mi away by about 1 ft, and reduced 

discharges from springs within a radius of 1,100 ft. From analyses of drawdown and recovery data from the production and 

observation wells, a median transmissivity value of 47,000 ft /d 

was calculated.

As shown on plate 3, the composite transmissivity of the 

Redwall-Leadville zone is estimated to range regionally from 

0.01 to 47.000 ft2/d. These estimates are based on three aquifer 

tests and the regional distributions of the thickness and unitaveraged hydraulic conductivity of the Redwall-Leadville zone. 

For comparison, three aquifer tests of the Madison Limestone in
17,550

17,60017,650

17,700

17,750

O <

17,800

17,850

17,900

I- 17,950

18,00018,05018,10018,150

18,200

I

MADISON 

LIMESTONE IN

BOREHOLE 

SB19-112-22CC

0 10 15

8,150

20

LEADVILLE 

LIMESTONE IN

BOREHOLE 

NMB38-18-04

Sonic log Density log Neutron log

8,425 - 8,450

10 15 20 

POROSITY, IN PERCENT

9,950

10,00010,050 - 10,100 - 10,150 - - 10,200 - 10,250 - 10,300 - 10,350 - 10,400 - 10,450

30 0

REDWALL

LIMESTONE IN

BOREHOLE

SLD23-18-20

73sO

z >

1

 rimJO

in

fI-o

s

JO

8JO

> D 

O

2 <a73 CO

tn X n

c

D

o

FIGURE 43. Relation of geophysieally determined porosity to depth below land surface in component geologic units of the Redwall-Leadville zone of the Madison aquifer.

Z CD
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS AQUIFER SYSTEM B67

1,000

100

Kj 10

o 

<r

CD 

<

0.1

0.01

0.001

LIMESTONE

1,000

100

a 10 I

5 10 

POROSITY, IN PERCENT

15

0.1

0.01

0.001

DOLOMITE

£^3& ^

 ®

«

«

; .

 «

10 15 

POROSITY, IN PERCENT

20 25

FIGURE 44. Relation of porosity to pore-scale permeability in samples of limestone and dolomite 

from the Redwall-Leadville zone of the Madison aquifer.

the Bighorn Basin of Wyoming indicated transmissivity values 

ranging from 72 to 1,900 ft2/d (Cooley, 1985, p. 39). Downey 

(1984, p. 22 23) estimated the transmissivity of the Lodgepole 

and Mission Canyon Limestones in the Powder River Basin of 

northeastern Wyoming and south-central Montana to range from 

less than 250 to more than 4,000 ft2/d using the three-dimensional 

finite-difference model of Trescott (1975). Drill-stem tests of the 

Madison Group in Montana indicated transmissivity values 

ranging from 0.043 to 5,400 ft2/d (Konikow, 1976, p. 10; 

Downey, 1984, p. 23). Step-drawdown pumping tests at one site 

in Montana indicated transmissivity values of 32,000 to 

45,000 ft2/d. Collectively, the data from Wyoming and Montana 

indicate a transmissivity range of 0.043 to 45,000 ft2/d for rocks 

equivalent to those of the Redwall-Leadville zone, which 

supports the estimated range in composite transmissivity for the 

Redwall-Leadville zone in the UCRB.

The aquifer test at Glenwood Springs indicated a storativity 

of 0.0005. Dividing this value by the thickness of the RedwallLeadville zone in the test area (280 ft) gives a specific storage 

of 0.000002 ft" 1 . If this specific storage applies for the entire 

UCRB, then the storativity where the Redwall-Leadville zone is 

at least 100 ft thick would range from 0.0002 to 0.005.

YIELDS FROM WELLS AND SPRINGS

Yields from the Redwall-Leadville zone of the Madison 

aquifer to wells and springs are small to moderate in most areas 

of the UCRB, but they can be very large in uplifted areas near 

faults (pi. 3). Yields from 227 drill-stem tests, flowing wells, 

and springs ranged from less than 1 to 45,000 gal/min, with a 

median value of 24 gal/min (fig. 48). Yields from wells in 

basins typically are less than 50 gal/min, whereas many wells 

and springs in or on the margins of uplifted areas discharge at 

rates of several hundred to several thousand gallons per minute 

(see, for example, Boettcher, 1972; Hampton, 1974; Lines and 

Glass, 1975; Hood and others, 1976; Sumsion, 1976). Flowing 

wells with large discharges include the Redstone 21-9 well 

(SC06-89-09bba) at Glenwood Springs, Colo., (1,500 to 

2,300 gal/min), and the Paradise no. 3 well (SC02-84-02bc) at 

McCoy, Colo. (3,200 to 9,400 gal/min). Large springs include 

Big Spring (UB01-08-17cbb) in the Uinta Mountains (2,240 to 

6,940 gal/min), Hogsback Spring (SB26-114-01 bac) in the 

Overthrust Belt (5,500 gal/min), and the Yampa Hot Spring 

(SC06-89-09ada) at Glenwood Springs, Colo. (2,950 gal/min). 

Collectively, 18 hot springs and seepage areas at Glenwood 

Springs discharge at a rate of 4,300 gal/min (Geldon, 1989c). 

Geothermal wells and springs at Ouray, Colo., discharge at
B68 REGIONAL AQUIFER SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

HYDRAULIC CONDUCTIVITY, IN FEET PER DAY 

D.OOODI 0.000032 o.oooi 0.00032 0.001 0.0032 0.01 0.032 0.1 0.32 1.0 3.2 10 32 100 320

8 

6 

4 

2

0

-5

-

LIMESTONE

-

0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0 0.5 1.0 1.5 2.0 2.

LOG (BASE 10} OF HYDRAULIC CONDUCTIVITY, IN FEET PER DAY

HYDRAULIC CONDUCTIVITY, IN FEET PER DAY 

0.000010.0000320.00010.000320.001 0.0032 0.01 0.032 0.1 0.32 1.0 3.2

^u

15

>

CJ

Sio

a

Lil

1C

U_

5 

n

1 1

DOLOMITE

- -

_ ...._

-5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0 0.5 

LOG (BASE 10} OF HYDRAULIC CONDUCTIVITY, IN FEET PER DAY

FIGURE 45. Frequency distribution of hydraulic conductivity in limestone and dolomite intervals 

of the Redwall-Leadville zone of the Madison aquifer.
BOREHOLE DH-109 

(UA02-01-07abc)

Limestone and limestone breccia

Vuggy, thin to medium 

bedded, laminated finely

to coarsely crystalline

limestone with abundant

shale .and carbonaceous

partings

Q X LU t/) tr.

Sandstone and siltstone

Siltstone and shale

X

IOo 

358

oI2G

acn cn |

400

BOREHOLE DH-107 

(UA02-01-07acb)

I I I I I I I

Limestone and chert

Vuggy,,thick,bedded, finely to 

coarsely crystalline limestone wtthshale and carbo.naceous partings

Limestone breccia

Vuggy,,thfn'-to medium 

bedded/.laminated finely

,to;co'arse(y. crystalline

liniestone',yvith abundant

shale and carbonaceous

partings

0.001 0.01 0.1 

HYDRAULIC CONDUCTIVITY, IN FEET PER DAY

10

FIGURE 46. Relation of the hydraulic conductivity of the Madison Limestone to depth below land surface in boreholes at the Whiterocks River damsite, Utah

(data furnished by Bureau of Reclamation, written commun., 1983-85). m
B70 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

1.0

0.9

0.8

0.7

0.6

> 0.5

0.4

0.3

0.2

0.1 -

Type curve of Cooper and others (1967) 

for o< = 0.001. Match is at 0 = 1 and 

T = 3,600 seconds

I I I

100 1,000 10,000 100,000

TIME, IN SECONDS

FIGURE 47. Head recovery in well OX-5 (NMB44-07-31cbd4) during "airlift test" of Leadville Limestone at Ouray, Colorado, 

July 15, 1987 (data from David Vince, City of Ouray, written commun., 1988).

average rates ranging from 2 to 340 gal/min, and, collectively, 

seven warm and hot springs at Ouray discharge from the 

Leadville Limestone or overlying alluvium at an average rate of 

672 gal/min (David Vince, City of Ouray, written commun., 

1988).

The largest discharges from the Rcdwall-Leadville zone 

result from unusual hydrological conditions. Pole Creek Spring 

(UB03-02-34d), with a discharge ranging from 900 to 

11,000 gal/min, is the outlet for Pole Creek Sink (Maxwell and 

others, 1971, p. 17). Blue Spring (GA32-07-3 Ib) and two other 

springs in the canyon of the Little Colorado River with discharges 

ranging from 11,000 to 45,000 gal/min (Cooley, 1976) are outlets 

for the entire Four Corners aquifer system and probably the 

Canyonlands aquifer, as well, for all of the area between the 

Uncompahgre Plateau and Mogollon Rim (see pi. 1 for locations 

of these areas). Springs issuing downstream from sinks or in 

subregional discharge areas result more from unique topographic

situations and the flow-system configuration than from the transmissivity of the Redwall-Leadville zone and, consequently, are 

considered atypical of the Redwall-Leadville zone in the UCRB.

DARWIN-HUMBUG ZONE OF 

THE MADISON AQUIFER

The Darwin-Humbug zone of the Madison aquifer is present 

only in and near the Uinta Mountains and Uinta Basin and on 

the flanks of uplifts bordering the greater Green River Basin 

(the Overthrust Belt, Gros Ventre Range, and Wind River 

Mountains). It consists of the Humbug Formation, the Bull 

Ridge Member of the Madison Limestone, the upper part of the 

Mission Canyon Limestone, and the Darwin Sandstone 

Member of the Amsden Formation (table 1). Component 

geologic units are Early to Late Mississippian in age.
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS AQUIFER SYSTEM B71

Little has been written about the water-supply capabilities of 

the geologic units that compose the Darwin-Humbug zone, and 

few data have been collected to quantify hydrologic properties of 

this zone. In the Uinta Mountains, the Humbug Formation 

contains fractures, solution channels, and breccia zones that can 

transmit water. A combination of these features allows the flow 

of Little Brush Creek to disappear into a cavern in the Humbug

Formation, travel through the Humbug Formation to the Madison 

Limestone, and emerge as a spring in Brush Creek (Maxwell and 

others, 1971). The Darwin Sandstone Member of the Amsden 

Formation probably transmits water readily in the UCRB because 

it yields small quantities of water to wells and springs in the 

Bighorn Basin (Cooley, 1985, p. 8). Based on their lithology, the 

Bull Ridge Member of the Madison Limestone and the upper

0.25 0.40 0.63

40

1.0 1.6 2.5 4.0 6.3 10 16

35

30

25

(j 

I 20

a

15

10

YIELD, IN GALLONS PER MINUTE 

25 40 63 100 160 250 400 630 1,000 1,6002,500 4,000 6,30010,00016,00025,00040,000 63,000

"1 I I I I i I I I I I T

Springs

Wells

-0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8

LOG (BASE 10) OF YIELD, IN GALLONS PER MINUTE

FIGURE 48. Frequency distribution of yields from the Redwall-Leadville zone of the Madison aquifer.
B72 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

Mission Canyon Limestone probably have hydrologic properties 

similar to the Humbug Formation and Darwin Sandstone 

Member. Where fractures, solution channels, breccia zones, or 

loosely cemented sandstone interbeds are absent, the DarwinHumbug zone probably docs not transmit much water. For this 

reason and because of its limited distribution, the DarwinHumbug zone can be expected to function as an aquifer 

subregionally in the UCRB.

THICKNESS AND LITHOLOGY

The thickness of the Darwin-Humbug zone ranges from 0 

to more than 600 ft (fig. 49). The hydrogeologic unit consists 

of variable proportions of limestone, dolomite, sandstone, 

shale, solution breccia, and gypsum. Carbonate rocks account 

for more than 75 percent of the Darwin-Humbug zone in the 

centers of depositional areas. Sandstone layers increase in 

abundance away from depositional centers as carbonate layers 

decrease. Carbonate layers typically are brecciated, and sandstone layers are brecciated in the western part of the UCRB. 

Gypsum layers are abundant at the northern end of the Hoback 

Range in Wyoming. Contacts with Mississippian and 

Pennsylvanian formations that comprise the overlying Four 

Corners confining unit generally are conformable.

POROSITY, PERMEABILITY, AND 

HYDRAULIC CONDUCTIVITY

Regional variations in porosity cannot be established with 

certainty from the limited data that were obtained during this 

study. In 13 samples of sandstone from the Humbug Formation, 

porosity ranged from 1.4 to 16 percent, with a median value of 

8.6 percent. It is estimated that the Darwin Sandstone Member of 

the Amsden Formation and sandstone layers in the upper part of 

the Mission Canyon Limestone and Bull Ridge Member of the 

Madison Limestone have a similar range in porosity. The porosity 

of carbonate layers probably is similar to that of carbonate rocks 

in the Rcdwall-Leadville zone of the Madison aquifer (see 

table 8) into which the Darwin-Humbug zone grades.

The small amount of permeability and hydraulic-conductivity 

data for the Darwin-Humbug zone that was available was consistently in the moderate range. Samples of sandstone from the 

Humbug Formation obtained from a borehole near Jensen, Utah 

(SLD05-23-18cca), had pore-scale permeability values ranging 

from 0.08 to 60 md, with a median value of 7.5 md (which is 

equivalent to a hydraulic-conductivity value of 0.011 ft/d). A 

drill-stem test in a borehole (SB08-99-17) near Maybell, Colo., 

indicated a local-scale permeability value of 292 md and a 

hydraulic-conductivity value of 0.71 ft/d for interbeddcd dolomite, sandstone, and shale in the Humbug Formation. These data 

are too limited to be representative of regional variations in 

permeability and hydraulic conductivity within the DarwinHumbug zone that might be expected from the lithology of the 

zone.

TRANSMISSIVITY

The drill-stem test near Maybell indicated a transmissivity 

of 110 ft/d for the Humbug Formation, assuming that the 

tested interval is representative of the entire formation at the 

test site. The drill-stem test was done on the Axial Basin Arch, 

which, like other uplifted areas, contains a fracture system that 

enhances secondary permeability and transmissivity. It is estimated that transmissivity values in structural basins are 

smaller than the value indicated by the drill-stem test on the 

Axial Basin Arch. Conversely, transmissivity values in areas 

with well-developed networks of solution channels and fractures, such as the southeastern Uinta Mountains, are estimated 

to be larger than the value indicated by the Maybell drill-stem 

test. On the basis of the rock types present in the DarwinHumbug zone and the existence of fracture-solution channel 

networks within this zone, the Darwin-Humbug zone is 

believed to be almost as transmissive as the Redwall-Leadville 

zone in places, and its transmissivity tentatively is estimated 

to range from 0.01 to 1,000 ft2/d.

YIELDS FROM WELLS AND SPRINGS

Yields of water from the Darwin-Humbug zone to wells 

typically do not exceed 50 gal/min. In four drill-stem tests of 

the Humbug Formation and the Darwin Sandstone Member 

of the Amsden Formation, yields ranged from 7.2 to 

34 gal/min, with a median value of 8.7 gal/min. However, a 

spring issuing from the Humbug Formation in the Uinta 

Mountains (UB02-07-36aba) has an estimated discharge of 

900 gal/min. According to Hood (1976, p. 11), such large 

discharges are possible from the Humbug Formation wherever a karst topography has developed. By analogy, similarly 

large discharges to wells and springs from the upper part of 

the Mission Canyon Limestone and the Bull Ridge Member 

of the Madison Limestone may be possible where karst 

topography has developed in the Overthrust Belt, Gros 

Ventre Range, and Wind River Mountains.

HYDROLOGIC PROPERTIES OF THE 

FOUR CORNERS CONFINING UNIT

Overlying the Four Corners aquifer system throughout 

most of the UCRB is a thick stratigraphic sequence 

composed mostly of shale, anhydrite, gypsum, halite, and 

carbonate rocks that generally inhibits ground-water movement between overlying and underlying aquifers. These 

rocks comprise the Four Corners confining unit, which is 

absent only in Wyoming east of the Overthrust Belt and north 

of the Rock Springs Uplift, in the central UCRB on and adjacent to the Uncompahgre Plateau, and along the southwestern edge of the UCRB in and adjacent to the High
HYDROLOG1C PROPERTIES OF THE FOUR CORNERS CONFINING UNIT B73

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

 /." *.*." -1 Area where Darwin-Humbug zone is 

missing because of erosion or 

nondeposition

i Area where Darwin-Humbug zone

consists of sandstone and shale with 

less than 25 percent carbonate 

interbeds

Area where Darwin-Humbug zone 

consists of sandstone, shale, 

limestone, and dolomite Carbonate 

rocks commonly are brecciated. Gypsum 

is present iocaily

 200 Line of equal thickness Interval, in feet, 

is variable

/ ' .' ' .' ' .' ' .'-'l 1TAH' .'A .' '' ' IJf-'' ." ' '." ' .' ' .' ' .' ' .' ' ."^ .feilsmiSn'w X- /.' ;. ,

/ - . . . y'/Tl>.-'X-'.r.®''. » . . . . -. ^t-. ;^*sfti'-TV. -v

V:-v .Binff.

& 

, * 7j£_

\Shiprock

, Durango

 "/

:is. /r '.NEW-:

/ MEXICO '//,:'/ '' 

'#///.-

^ :--^'

\ AREA EXCLUDED 

FROM STUDY

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 49. Thickness and lithology of the Darwin-Humbug zone of the Madison aquifer. 

(Modified from Geldon, in press, pi. 12.)
B74 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

Plateaus region. The Four Corners confining unit is divisible 

vertically into two subunits with different lithologic and 

hydrologic properties, the Belden-Molas and Paradox-Eagle 

Valley subunits.

BELDEN-MOLAS SUBUNIT

The Belden-Molas subunit of the Four Corners confining 

unit consists of the Horseshoe Shale Member of the Amsden 

Formation, Doughnut Shale, Surprise Canyon Formation, 

Watahomigi Formation. Molas Formation, lower member of 

the Hermosa Formation, and Belden Formation (table 1), 

which are Late Mississippian to Middle Pennsylvanian in 

age. Because component geologic units are mostly shale, the 

Belden-Molas subunit generally has negligible permeability. 

In the Paradox Basin, for example, drill-stem tests of the 

Molas Formation and lower member of the Hermosa 

Formation produce so little water that only the Paradox 

Member of the Hermosa Formation and, in some of the area, 

the Ignacio Quartzite are considered to be less permeable 

(Rush and others, 1982: Weir and others. 1983a; Whitfield 

and others, 1983). The Doughnut Shale in the Uinta Mountains (Sumsion, 1976, p. 23), Uinta Basin (Hood, 1976, 

p. 11), and San Rafael Swell (Hood and Patterson, 1984, 

p. 55), the Horseshoe Shale Member of the Amsden 

Formation in the Rawlins Uplift (Berry, 1960, p. 13) and 

Overthrust Belt (Lines and Glass, 1975), and the Supai 

Group (including the Watahomigi Formation) in the Grand 

Canyon (Metzger, 1961, p. 118) also yield little or no water. 

The Belden Formation generally produces little or no water, 

but spring and artesian-well discharges occur in the White 

River Plateau and Elk Mountains where faults allow movement of water into the formation from the Leadville 

Limestone (Barren and Pearl, 1977, p. 85: Geldon. 1989c). 

On the basis of predominant characteristics, this hydrogeologic unit is a major impediment to ground-water movement throughout the UCRB and, thus, was classified as part 

of a confining unit in this investigation.

THICKNESS AND LITHOLOGY

The thickness of the Belden-Molas subunit ranges from 0 

to more than 3,000 ft (fig. 50). Regionally, the hydrogeologic 

unit consists predominantly of dark gray, black, and red shale 

with subordinate limestone, dolomite, and sandstone and 

minor gypsum. In most areas, shale accounts for 50 to more 

than 75 percent of the Belden-Molas subunit. However, in the 

Washakic Basin and depositional centers south of the Uinta 

Mountains and Axial Basin Arch, limestone and dolomite 

layers can equal or exceed shale layers in abundance, and, 

locally, carbonate rocks account for more than 75 percent of 

the unit. Sandstone layers compose about one-third of the

unit where it thins on the flanks of uplifted areas. Contacts 

with Upper Mississippian and Pennsylvanian geologic units 

generally are conformable to gradational.

POROSITY AND PERMEABILITY

In considering the hydrologic properties of the Belden-Molas 

subunit, quantitative assessment was hindered by the sparse 

distribution of available data, most of which is from the lower 

member of the Hermosa Formation. However, it was possible to 

estimate hydrologic properties using data from approximately 

synchronous geologic units containing different proportions of 

the same rock types. In this analysis, data from the Paradox and 

upper members of the Hermosa Formation, Round Valley 

Limestone. Amsden Formation, and Cutler Formation were used.

The available data indicate that hydrologic properties of the 

Belden-Molas subunit depend on both lithology and structural 

setting. In 17 samples of limestone and dolomite from the lower 

member of the Hermosa Formation, porosity ranged from 0.3 to 

7.9 percent, with a median value of 2.1 percent (fig. 51). On the 

basis of 48 samples of shale from the Hermosa Formation 

(fig. 51), it is estimated that the porosity of shale in the BeldenMolas subunit ranges from less than I to 13 percent, with a 

median value of about 2 percent. Analyses of samples from the 

Molas, Hermosa, and Cutler Formations indicate that in the 

Belden-Molas subunit, the median porosity of quartz sandstone 

probably is between 6 and 7 percent, and the median porosity of 

arkosic (red) sandstone probably is between 10 and 11 percent. 

On the basis of lithologic composition and the above-cited 

values of median porosity, it is estimated that the unit-averaged 

porosity of the Belden-Molas subunit ranges regionally from 

less than 2 to about 6 percent (fig. 52).

The permeability of the Belden-Molas subunit varies 

from small to moderate. In 17 analyses of limestone and 

dolomite from the lower member of the Hermosa Formation, 

pore-scale permeability ranged from less than 0.01 to 45 tnd, 

with a median value of less than 0.01 md. On the basis of 48 

analyses for the entire Hermosa Formation (fig. 53), the 

pore-scale permeability of shale in the Belden-Molas subunit 

is estimated to range from less than 0.0001 to 18 md, with a 

median value of less than 0.01 md. On the basis of 176 analyses of samples from the Molas and Hermosa Formations, 

the pore-scale permeability of sandstone in the BeldenMolas subunit is estimated to range from 0.0001 to 25 md, 

with a median value of about 0.01 md. Because the data are 

limited, it is impossible to state conclusively whether porescale permeability in the Belden-Molas subunit depends on 

porosity, but a relationship appears to exist for dolomite 

(table 3).

Values of local-scale permeability in the Bcldcn-Molas 

subunit reflect the influence of fracturing and other secondary 

openings and are larger, on the average, than values of pore-scale 

permeability. In 15 drill-stem tests, local-scale permeability
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS CONFINING UNIT B75

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

r.. .. .1

];. '/.' ';.[ Area where Belden-Molas subunit is 

missing because of erosion or 

nondeposition

____ Area where Belden-Molas subunit consists 

of shale, limestone, and dolomite with 

less than 10 percent sandstone interbeds

Area where Belden-Molas subunit consists 

of shale, limestone, dolomite, and 

sandstone

 200 Line of equal thickness Interval is 200 

feet, except north of Glenwood Springs, 

Colorado, where interval us 1,000 feet

Data sites Number is hydraulic conductivity, in 

0.007 feet per day

0.05 

A Site at which unit-averaged hydraulic

conductivity was estimated from permeability 

determined by one or more drill-stem tests 

0.007 

 Site at which unit-averaged hydraulic

conductivity was determined by one or more 

bailing tests

I AREA EXCLUDED 

FROM STUDY

50

I

75 100 MILES

I_____|

25 50 75 100 KILOMETERS

FIGLRH 50. Thickness, lithology, and unit-averaged hydraulic conductivity of the Belden-Molas subunit of the Four Corners confining unit.

(Modified from Geldon, in press, pi. 13.)
B76 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

A. CARBONATE POROSITY IN LOWER MEMBER OF HERMOSA 

FORMATION

o

Dolomite 

Limestone

23456 

POROSITY, IN PERCENT

B. SHALE POROSITY IN THE HERMOSA FORMATION

20

15

310

a

5678 

POROSITY, IN PERCENT

10 11 12 13

FIGURE 51. Frequency distribution of porosity in carbonate rocks and shale from the Hermosa Formation.
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS CONFINING UNIT B77

 . . . . . .V4X-::-.:-\ n

I-.'-/.'-'. .H-pl'.1rt'a.K-'.-.-^. Lander

42

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

 .' -' ] Area where Belden-Molas subunit is 

missing because of erosion or 

nondeposition

2.5 Line of equal estimated unit-averaged 

porosity Location is approximate. 

Interval is 0.5 percent, except in a 

small area northeast of Cortez, 

Colorado, where interval is 1 percent

AREA EXCLUDED 

FROM STUDY

50 75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 52. Estimated distribution of unit-averaged porosity in the Belden-Molas subunit of the Four Corners confining unit.
B78 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN. EXCLUDING SAN JUAN BASIN

0.00001

50

40

PERMEABILITY. IN MILLIDARCIES 

0.1 0.32 1.0 3.2 10 32 100

>- 30

O

u. 20

10

-5.0 -1.0 -0.5 0 0.5 1.0 1.5 

LOG (BASE 10) OF PERMEABILITY, IN MILLIDARCIES

2.0

FIGURE 53. Frequency distribution of pore-scale permeability 

in samples of shale from the Hermosa Formation.

ranged from 0.0012 to 130 md, with a median value of 1.1 md. 

Most of the tested intervals consisted of limestone or dolomite 

and shale; two intervals also contained sandstone.

HYDRAULIC CONDUCTIVITY AND TRANSMTSSIVITY

The drill-stem test data for the Belden-Molas subunit discussed 

in the previous section are equivalent to hydraulic-conductivity 

values with a range of 0.000029 to 0.32 ft/d. Bailing and pressureinjection tests at the Ruedi Dam site that were conducted by the 

Bureau of Reclamation (written commun.. 1985) indicate additional values of hydraulic conductivity. Two pressure-injection 

tests in a 44-ft-thick interval of gypsiferous mudstone and siltstone 

of the Belden Formation in well DH-61 (SC08-84-l7bac2 ) indicated an average hydraulic-conductivity value of 0.54 ft/d. Nine 

pressure-injection tests in a 102-ft-thick interval of sandstone, siltstone, and mudstone of the Belden Formation in well DH-62 

(SC08-84-l7bacj) indicated hydraulic-conductivity values 

ranging from 0.089 to 5.9 ft/d: a bailing test in this same well that 

was analyzed by the method of Skibitzke (1958) indicated a 

hydraulic-conductivity value of 0.073 ft/d. Residual drawdown 

data for a bailing test in well DH-13 (SC08-84-07caa), perhaps, 

indicate the most representative hydraulic-conductivity value for 

the Belden Formation in the Ruedi Dam area. These data, shown in 

figure 54, were obtained from an 86.4-fl-thick section of gypsiferous siltstone and claystone. During the test, 3.7 gallons were 

bailed in 225 minutes, which is equivalent to an average discharge 

of 0.016 gal/min, or 3.2 ft/d. The transmissivity calculated using 

equation 15 was:

-r _ 35.2 x 0.016 gal/min _ 

(2.78-1.82)ft

ft'M

and the hydraulic conductivity, calculated by dividing the transmissivity by the test-interval thickness, was 0.007 ft/d.

The complete range in hydraulic-conductivity values for the 

Belden-Molas subunit determined from 15 drill-stem tests. 

3 laboratory determinations of permeability, the average of 

2 injection tests in 1 borehole interval, and 2 bailing tests is 

0.000013 to 0.54 ft/d, (fig. 55); the median of these hydraulicconductivity values is 0.0046 ft/d. Keeping in mind that the data 

are skewed toward the relatively few aquifer tests in the BeldenMolas subunit that yielded water, the range in and median 

values for this hydrogeologic unit probably are smaller than 

what can be ascertained from the available data. In areas where 

the Belden-Molas subunit is mostly shale and deeply buried, the

2 345 

TIME SINCE BAILING STARTED 

TIME SINCE BAILING STOPPED

FlGlRE 54. Residual drawdown in well DH-13 (SC08-84-07caa) at 

Ruedi Dam site, Colorado, during bailing test of Belden Formation 

in March 1963 (data from Bureau of Reclamation, written commun., 

1985).
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS CONFINING UNIT B79

0.00 

5

4 

2

L1J 

O

CC"" 2

1 

n

HYDRAULIC CONDUCTIVITY, IN FEET PER DAY 

0010.0000320.00010.00032 0.001 0.0032 0.01 0.032 0.1 0.32 1.0

1 1

5

-

-5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0 

LOG (BASE 10) OF HYDRAULIC CONDUCTIVITY, IN FEET PER DAY

FIGURE 55. Frequency distribution of hydraulic conductivity in the 

Belden-Molas subunit of the Four Corners confining unit.

hydraulic conductivity probably is negligible. Conversely, intervals of loosely consolidated sandstone and siltstone that are 

present in uplifted areas and shallow basins, such as the Eagle 

Basin, eastern Paradox Basin, and Kaibab Plateau, may have 

hydraulic-conductivity values that are larger than the maximum 

known value for the Belden-Molas subunit. On the basis of the 

limited available data, unit-averaged hydraulic conductivity is 

estimated to range from 0.00001 to less than 1.0 ft/d (fig. 55). 

The composite transmissivity of the Belden-Molas subunit, as 

determined from regional distributions of unit-averaged 

hydraulic conductivity and thickness and the bailing tests in 

wells DH-13 and DH-62, is estimated to range from 0.001 to 

50 ft2/d.

YIELDS FROM WELLS AND SPRINGS

Reflecting the generally small transmissivity, well and 

spring discharges from the Belden-Molas subunit rarely exceed 

30 gal/min (fig. 56). In 15 drill-stem tests, yields from the 

Belden Formation, Doughnut Shale, Molas Formation, and 

lower member of the Hermosa Formation ranged from 1.0 to 

30 gal/min, with a median value of 9.4 gal/min. Many other 

drill-stem tests, however, produced loo little water to obtain a 

measurable discharge. During drilling of an exploration hole 

(SC08-84-14baa) at the Ruedi Dam site, water flowed from 

faulted and brecciated shale and limestone in the Belden

Formation at a rate of more than 100 gal/min, but this discharge 

decreased to 8 gal/min by the time the hole was completed 

(Bureau of Reclamation, Denver, Colo., written commun., 

1985). Four springs issuing from the Belden Formation at 

Dotsero, Colo., discharge at rates of 9 to 18 gal/min, but some 

of the water discharging from these springs may originate in the 

Leadville Limestone of the underlying Madison aquifer. The 

largest known yields from the Belden-Molas subunit in the 

UCRB are to two springs on the White River Plateau. These 

springs, according to Teller and Welder (1983), have moderate 

yields of 102 to 266 gal/min.

PARADOX-EAGLE VALLEY SUBUNIT

The Paradox-Eagle Valley subunit of the Four Corners 

confining unit consists of the Moffat Trail Limestone Member 

of the Amsden Formation, the Round Valley Limestone, the 

Eagle Valley Evaporite, the Paradox Member of the Hermosa 

Formation, and the Manakacha Formation of the Supai Group 

(table 1). Component geologic units are Late Mississippian to 

Middle Pennsylvanian in age. Together with the Belden-Molas 

subunit, the Paradox-Eagle Valley subunit so thoroughly retards 

ground-water movement that aquifers above and below are 

effectively isolated, except in areas of structural disturbance. In 

the Paradox Basin, for example, studies by Thackston and 

others (1981), Woodward-Clyde Consultants, Inc. (1982), and 

INTERA Environmental Consultants, Inc. (1984), concluded 

that water in the Paradox Member is isolated from any regionally connected flow system and that significant vertical and 

horizontal movement of water through this geologic unit is 

possible only where bedded evaporites that form most of the 

Paradox Member are penetrated by open fractures and faults or 

thinned by plastic deformation. Studies by the U.S. Geological 

Survey in the Paradox Basin (Rush and others, 1982; Weir and 

others, 1983a. 1983b; Whitfield and others, 1983) found that 

only 24 percent of all drill-stem tests in the Paradox Member 

produced enough water to calculate a meaningful discharge and 

that the Paradox Member was less permeable than all other 

geologic units of Cambrian to Tertiary age in the area. The 

Eagle Valley Evaporite, which is very similar to the Paradox 

Member, is presumed to be nearly as resistant to ground-water 

movement, although it locally supplies small quantities of fresh 

to brackish water to wells and springs (Brogden and Giles, 

1976a; Giles and Brogden, 1976). Nothing is known about the 

water-bearing properties of the Round Valley Limestone, 

Moffat Trail Limestone Member, or Manakacha Formation, but 

an unspecified interval of cherty limestone in the Amsden 

Formation in the Overthrust Belt (if not the Moffat Trail 

Limestone Member, then a lithologically similar interval) 

discharges a small quantity of water to a well (Lines and Glass, 

1975), and small springs issue from unspecified intervals in the 

Supai Group in the Grand Canyon (Metzger, 1961). Because the 

most important characteristic of this hydrogeologic unit is its
B80 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

1.0

>- 

(J

2 -

1.6 2.5 4.0 6.3

YIELD, IN GALLONS PER MINUTE 

10 16 25 40 63 100 160 250 400

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8

LOG (BASE 10) OF YIELD, IN GALLONS PER MINUTE

2.0 2.2 2.4 2.6

FIGURE 56. Frequency distribution of yields from the Belden-Molas subunit of the Four Corners confining unit.

resistance to ground-water movement, the Paradox-Eagle 

Valley subunit was classified as part of a confining unit in this 

investigation.

THICKNESS AND LITHOLOGY

The thickness of the Paradox-Eagle Valley subunit ranges 

from 0 to more than 6,000 ft (fig. 57), except in small areas of 

the Paradox Basin where salt diapirs as much as 15,000 ft 

thick are present. Regionally, the Paradox-Eagle Valley 

subunit consists of varying proportions of limestone, dolomite, shale, sandstone, gypsum-anhydrite, and halite. 

Gypsum-anhydrite, halite, shale, and minor carbonate rocks 

are the dominant rock types in and near the Paradox and Eagle 

Basins. This hypersaline facies grades outward in and near the 

two basins into a penesalinc facies composed of limestone, 

dolomite, shale, gypsum-anhydrite, and sandstone, which, in 

turn, grades outward into a marine-shelf facies composed of 

limestone and dolomite with subordinate shale and minor 

sandstone. The marine-shelf facies predominates from the 

Uinta and Sand Wash Basins to the northern edge of the 

UCRB. On the southern edge of the UCRB, a facies consisting 

of red shale and sandstone, subordinate carbonate rocks, and 

minor gypsum-anhydrite is present. Contacts between component geologic units and geologic units that comprise the overlying Canyonlands aquifer generally are gradational to 

disconformable.

POROSITY AND PERMEABILITY

Porosity in the Paradox-Eagle Valley subunit varies widely 

from place to place and within vertical sequences because of 

considerable variations in lithology. Sandstone and dolomite, 

with median porosities of about 6 to 7 percent, are the most 

porous rock types (table 9). On the basis of 176 analyses of 

samples from the Molas and Hermosa Formations (fig. 58), sandstone porosity in the Paradox-Eagle Valley subunit is estimated 

to range from 0.1 to 21 percent, with a median value of about 

7 percent. In 729 analyses of dolomite from the Paradox-Eagle 

Valley subunit, porosity ranged from 0.1 to 31 percent, with a 

median value of 6.1 percent. In 1,649 analyses of limestone from 

the Paradox-Eagle Valley subunit, porosity ranged from less than 

0.1 to 32 percent, with a median value of 3.5 percent. For both 

dolomite and limestone, median porosity in the Paradox-Eagle 

Valley subunit generally was found to be larger in varieties with a 

tendency toward dissolution around inclusions, such as cherty or 

vuggy limestone and cherty, anhydritic, or vuggy dolomite, than 

in shaly varieties (table 9). Median porosity also was larger in 

granular (sucrose, chalky, or earthy) varieties of limestone and 

dolomite than in fine-grained or crystalline varieties. The porosity 

of shale in the Paradox-Eagle Valley subunit is estimated from 

samples from the entire Hermosa Formation to range from less 

than 1 to 13 percent, with a median value of about 2 percent. The 

porosity of anhydrite and halite in the Paradox-Eagle Valley 

subunit, based on 19 analyses of samples from the Paradox 

Member, is estimated to range from 0.2 to 2.5 percent, with a
HYDROLOCIC PROPERTIES OF THE FOUR CORNERS CONFINING UNIT B8I

42

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

 "." *.*" "' "."* ".*" ".* / Rnwlins

EXPLANATION

Area where Paradox-Eagle Valley 

subunit is missing because of erosion 

or nondeposition

Area where Paradox-Eagle Valley

subunit consists of limestone, dolomite, 

and shale with less than 10 percent 

sandstone interbeds and less than 5 

percent anhydrite interbeds

Area where Paradox-Eagle Valley

subunit consists of limestone, dolomite, 

shale, sandstone, and anhydrite

Area where Paradox-Eagle Valley subunit 

consists of anhydrite, gypsum, halite, 

and shale with less than 25 percent 

sandstone and carbonate interbeds

 400 Eine of equal thickness Interval, in 

fee[ is variable

AREA EXCLUDED 

FROM STUDY

50 75 100 MILES 

I r- I_____|_____|

0 25 50 75 100 KILOMETERS

FIGURE 57. Thickness and lithology of the Paradox-Eagle Valley subunitof the Four Corners confining unit.

(Modified from Geldon, in press, pi. 14.)
BS2 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

TABLE 9. Porosity and pore-scale permeability statistics fur the Paradox-Eagle Valley subunit of the Four Corners confining unit

[<. less than]

Rock type

Halite

Anhydrite

Shale 1

Sandstone"

Limestone

Fossiliferous

Shaly

Anhydritic

Algal

Dolomitic

Vuggy

Cherty

Brecciated

Crystalline

Fine grained

Sucrosic

Chalky

Earthy

All

Dolomite

Shaly

Anhydritic

Limy

Cherty

Vuggy

Fine grained

Crystalline

Earthy

Sucrosic

All

Minimum

0.2

2

.3

.1

.2

.3

.2

.8

.3

.3

1.4

.5

<.l

.3

.1

.4

2.4

<.l

.4

.6

.1

2.0

2.9

.3

.3

1.6

.3

.1

Porosity 

(percent)

Maximum

0.6

2.5

13

21

13.3

19.0

21.7

17.6

27.3

28.5

21.9

4.3

18.1

27.3

26.5

16.8

19.7

32.1

20.3

22.6

21.6

24.6

31.1

13.7

31.1

13.0

31.0

31.1

Median

0.4

.4

1.8

6.6

1.7

2.5

2.8

5.8

6.3

6.8

10.7

2.4

2.5

3.0

6.9

10.1

12.0

3.5

3.8

10.2

12.3

12.6

13.3

3.0

7.2

7.7

11.8

6.1

Number of 

observations

4

15

48

176

52

158

142

35

177

238

78

9

618

92

187

9

12

1.649

76

86

103

21

122

29

301

17

72

729

Pore-stale permeability 

(millidarcies)

Minimum Maximum

<0.()0()l 0.00022

.00017 27

<.001 18

.00019 25

<.OI 142

<.OI 142

<.01 43

<.01 22

<.()! 84

<.OI 2,435

<01 585

.03 1 14

<.01 2,435

<.()! 54

<.OI 1,291

<.OI 6.9

.00039 4.4

.00039 2.435

<.01 33

<.01 1,644

<.()! 3,460

<.01 699

.04 3,460

<.01 19

<.OI 3,460

.01 1.5

<.01 145

<.01 3,460

Median

0.0001

.04

<.01

.01

.05

.05

.17

.70

.18

1.3

2.8

.20

.04

.03

.79

.30

.32

.10

.01

4.9

5.8

.81

31

.04

.59

.08

1.2

.21

Number of 

observations

4

15

48

176

52

158

142

35

177

238

78

9

618

92

187

9

12

1,649

76

86

103

21

122

29

301

17

72

729

Includes samples from all members of the Hermosa Formation. 

"Includes samples from all members of the Hermosa Formation and the Molas Formation.

median value for each rock type of 0.4 percent. On the basis of 

lithologic composition and the above-cited median porosity 

values, unit-averaged porosity in the Paradox-Eagle Valley 

subunit is estimated to range regionally from less than 1 to more 

than 5 percent (fig. 59).

The permeability of the Paradox-Eagle Valley subunit 

varies from small to large, depending on the types of rocks 

present and the degree of fracturing and solution from area to 

area. Pore-scale permeability, which ranges from less than 

0.0001 to 3,460 md, is largest in dolomite and limestone,

intermediate in sandstone and anhydrite, and smallest in shale 

and halite (table 9). Carbonate textures affect pore-scale permeability in much the same way that they affect porosity. There 

appears to be no relation between pore-scale permeability and 

porosity for most rock types in this hydrogeologic unit (table 3). 

However, pore-scale permeability is related very crudely to 

porosity in limestone (fig. 60) and sandstone (table 3).

Reflecting the influence of secondary openings, median 

values of local-scale permeability are larger than median values 

of pore-scale permeability in carbonate, evaporite, and shale
FREQUENCY

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B84 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

BOUNDARY OF 

UPPER COLORADO ' s 

RIVER BASIN .../

108"

%^t$3^ '.vjxtiMitfG-'.1-' '. ' " :-v '-::/-::/o 

v.^VvVvy.-y.-v^vVvy-'y

)'." ' '." ' ".' " ".' ' '.' ' '.' ' './ Rawlhts

EXPLANATION

 '. ' . \ Area where Paradox-Eagle Valley

subunit is missing because of erosion 

or nondeposition

2 Line of equal estimated unit-averaged 

porosity Location is approximate. 

Interval is 1 percent

4.6

 Site of a borehole lithologically

similar to the entire Paradox-Eagle 

Valley subunit in the area, from which 

samples were obtained for porosity 

measurements Number is the mean 

of porosity values from the interval

AREA EXCLUDED 

FROM STUDY

0 25 50 75 100 MILES

I I_____|_____I_____|

I I I T I

0 25 50 75 100 KILOMETERS

FIGURE 59. Estimated distribution of unit-averaged porosity in the Paradox-Eagle Valley subunit of the Four Corners confining unit
HYDROLOGIC PROPERTIES OF THE FOUR CORNERS CONFINING UNIT B85

intervals. In 131 determinations (including 93 drill-stem tests, 

3 slug tests, and 35 calculations from the average pore-scale 

permeability in a borehole interval), local-scale permeability 

ranged from 0.0031 to 550 md, with a median value of 2.3 md 

(fig. 61). In tested intervals consisting entirely of limestone and 

dolomite, local-scale permeability ranged from 0.017 to 

350 md, with a median value of 7.1 md. In intervals consisting 

of carbonate rocks with shale, anhydrite, or halite interbeds, 

local-scale permeability ranged from 0.10 to 550 md, with a 

median value of 1.2 md. In intervals consisting entirely of shale, 

anhydrite, and halite, local-scale permeability ranged from 

0.0031 to 33 md, with a median value of 1.2 md. The local-scale 

permeability of halite was found in six tests to range from less 

than 0.01 to 8.4 md, with a median value of 0.36 md.

HYDRAULIC CONDUCTIVITY AND TRANSMISSIVITY

Values of hydraulic conductivity determined from the previously discussed permeability data and three slug tests ranged 

from 0.000008 to 1.5 ft/d (fig. 62), with median values of 

0.018 ft/d for limestone and dolomite intervals, 0.0036 ft/d for 

carbonate intervals with shale and evaporite interbeds, and 

0.0016 ft/d for intervals consisting of halite or anhydrite. On the 

basis of measurements of pore-scale permeability in a borehole in 

the Green River Basin (SB 14-112-06bab), the unit-averaged 

hydraulic conductivity of the Round Valley Limestone and the 

Moffat Trail Limestone Member of the Amsden Formation in 

most areas can be expected to be near the median hydraulic 

conductivity of carbonate rocks in the Paradox-Eagle Valley 

subunit and range from 0.01 to 0.03 ft/d (pi. 4). Three drill-stem 

tests in the Paradox Basin confirm that predominantly carbonate 

parts of the Paradox Member of the Hermosa Formation and the 

Eagle Valley Evaporite also can be expected to have unitaveraged hydraulic-conductivity values between 0.01 and 

0.03 ft/d. A drill-stem test near Meeker, Colo., and two drill-stem 

tests in the Henry Mountains Basin indicate that unit-averaged 

hydraulic-conductivity values of the Paradox Member and the 

Eagle Valley Evaporite should range from 0.003 to 0.007 ft/d 

where these geologic units consist of interbedded limestone, 

dolomite, sandstone, shale, and anhydrite. Drill-stem tests at six 

sites in the Paradox Basin indicate that unit-averaged hydraulicconductivity values of the Paradox Member and the Eagle Valley 

Evaporite should range from 0.002 to 0.006 ft/d where these 

geologic units consist of interbedded carbonate rocks, anhydrite, 

and shale. Drill-stem tests at five sites in the Paradox Basin, 

including GD-1 (table 10), indicate that unit-averaged hydraulicconductivity values of the Paradox Member and the Eagle Valley 

Evaporite should range from 0.001 to 0.005 ft/d where these 

geologic units consist mostly of interbedded anhydrite, gypsum, 

halite, and shale. Where the evaporites and interbeds are severely 

disturbed by diapiric intrusion, slug-injection tests at Salt Valley, 

in the Paradox Basin (table 11), indicate that unit-averaged 

hydraulic-conductivity values can be expected to range from less 

than 0.00001 to 0.00033 ft/d. Extrapolating from the above data,

10,000

o.oooi 10 20 

POROSITY, IN PERCENT

30 40

FIGURE 60. Relation of porosity to pore-scale permeability in limestone samples from the Paradox-Eagle Valley subunit of the Four 

Corners confining unit.

unit-averaged hydraulic conductivity in the Paradox-Eagle 

Valley subunit, then, can be expected to range regionally from 

less than 0.0001 to about 0.03 ft/d (pi. 4).

Based mainly on regional distributions of thickness and unitaveraged hydraulic conductivity, the composite transmissivity of 

the Paradox-Eagle Valley confining unit is estimated to range 

from about 0.05 to 15 ft2/d (pi. 4). These values are small to 

moderate. Because structural setting mostly was ignored in estimating composite transmissivity, actual values could be larger 

within and adjacent to uplifted areas, where all rock types tend to 

be fractured, and carbonate rocks tend to be cavernous. Actual 

values could be smaller in the center of structural basins because 

the effects of compaction were not considered. Given these limitations, the distribution of composite transmissivity appears to 

differ markedly north and south of the Uncompahgre Plateau. 

North of the plateau, there appears to be a progressive increase in 

transmissivity westward from the Eagle Basin and White River 

Plateau to the vicinity of the Uinta Mountains and Uinta Basin. 

This trend is caused by a lithologic change from predominantly 

shale and evaporites to predominantly carbonate rocks in the 

direction of increasing transmissivity. South of the Uncompahgre
B86 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

Plateau, areas of alternately small and moderate transmissivity 

have a northwesterly alignment, in part because of lithofacies 

variations, but mainly because of the prevailing structural trend.

YIELDS FROM WELLS AND SPRINGS

Yields from the Paradox-Eagle Valley subunit to wells and 

springs typically are small, but moderate yields can occur. In 66 

drill-stem tests, yields from the Paradox Member of the 

Hermosa Formation, Round Valley Limestone, and Eagle 

Valley Evaporite ranged from 0.21 to 103 gal/min (fig. 63). 

Many other drill-stem tests produced either too little water or 

too much mud, oil, or gas to calculate a water yield. According 

to Hood and Patterson (1984, p. 54), a petroleum test well in the

San Rafael Swell flowed water at rates of 20 to 146 gal/min 

while being drilled. South of Glenwood Springs, Colo., wells 

developed in the Eagle Valley Evaporite yield water at rates of 

5 to 25 gal/min with unspecified drawdowns (Brogden and 

Giles, 1976a). Springflows from this hydrogeologic unit occur 

rarely. Stinking Springs (SLD24-24-21c), which issues from 

the Paradox Member of the Hermosa Formation in the Paradox 

Basin, has a discharge of 20 to 30 gal/min (Ritzma and 

Doelling, 1969, p. 106); Onion Creek Spring (SLD24-24-22), 

in the same area, has a discharge of 55 gal/min (Rouse, 1967, 

p. 19). Tripp Hot Spring (NMB36-09-10bcb) and Trimble Hot 

Spring (NMB36-09-l5bcb) near Durango, Colo., issue from 

the Paradox Member through overlying colluvium with

PERMEABILITY, IN MILLIDARCIES

0.001 0.0032 0.01 0.032 0.1 0.32 1.0 3.2 10

30

32 100 320 1,000

T T

25

Other

Halite or anhydrite

Shale, anhydrite, and halite

Limestone, dolomite, and 

shale, anhydrite, or halite

Limestone and dolomite

20

o

UJ 

OL

> 15

10

-3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0 0.5 1.0 1.5 

LOG (BASE 10) OF PERMEABILITY, IN MILLIDARCIES

2.0 2.5 3.0

FIGURE 61. Frequency distribution of local-scale permeability in the Paradox-Eagle Valley 

subunit of the Four Corners confining unit.
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER B87

HYDRAULIC CONDUCTIVITY, IN FEET PER DAY

0.000001 0.0000032 0.00001 0.000032 0.0001 0.00032 0.001 0.0032 0.01 0.032 0.1

30

0.32 1.0

T T

25

20

13 15 

O

10

I I I

Other

Halite or anhydrite

Shale, anhydrite, and halite

Limestone, dolomite, and 

shale, anhydrite, or halite

Limestone and dolomite

-6.0 -5.5 -5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 

LOG (BASE 10) OF HYDRAULIC CONDUCTIVITY, IN FEET PER DAY

-0.5 0.5 1.0

FIGURE 62. Frequency distribution of hydraulic conductivity in the Paradox-Eagle Valley subunit

of the Four Corners confining unit.

discharges of 15 to 24 gal/min (Barrett and Pearl, 1977, p. 240- 

242). Big Sulphur Spring (SC08-84-16aa), which issues from 

the Eagle Valley Evaporite near Meredith, Colo., has a 

discharge of 150 gal/min (Rouse, 1967, p. 14). Another spring 

issuing from the Eagle Valley Evaporite near Dotsero, Colo., 

Big Spring (SC05-86-05), was reported by lorns and others 

(1964) to have a discharge of 450 gal/min. However, water 

issuing from this spring probably originates in the Leadville 

Limestone and rises to the surface through interconnecting 

faults. Under most circumstances, discharges to wells and 

springs from the Eagle Valley Evaporite and other component 

geologic units of the Paradox-Eagle Valley subunit are not 

likely to exceed 150 gal/min.

HYDROLOGIC PROPERTIES OF THE 

CANYONLANDS AQUIFER

Rocks equivalent to the C multiple-aquifer of the Navajo 

and Hopi Indian Reservations in Arizona, New Mexico, and 

Utah (Cooley and others, 1969) extend throughout the UCRB. 

The C multiple-aquifer extends from the upper part of the Supai 

Group to the Kaibab Formation and, thus, includes all Paleozoic 

rocks above the Four Corners confining unit. To be consistent 

with current guidelines of the U.S. Geological Survey for 

naming hydrogeologic units (Laney and Davidson, 1986), the 

C multiple-aquifer herein is named the Canyonlands aquifer
REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

TABLE 10. Hydraulic conductivity of the Paradox Member of the 

Hermosa Formation in Borehole GD-1 (SLD30-21-21ddd)

[Drill-stem test data were compiled from Woodward-Clyde Consultants, Inc., 

1982, table 9-2. Location of borehole shown on plate 4]

Interval below 

Kelly bushing1 

(feet)

2,540-2,600

2,600-2,760

2,760-2,960

2,960-3,100

3,100-3,330

3,330-3,530

3,530-3,660

3,660-3,800

3,800-3,940

3,940^,030

4,030^,230

4,230-4,730

4,730^,950

4,950-5,090

5,090-5,200

5,200-5,340

5,340-5,450

Lithology

Limestone

Dolomite, anhydrite, shale

Limestone, dolomite, anhydrite, shale

Limestone, dolomite, anhydrite, shale

Anhydrite, shale, halite

Anhydrite, shale, halite

Halite

Anhydrite

Anhydrite, shale, halite

Halite

Anhydrite shale, halite

Halite with anhydrite and shale

Anhydrite, shale, halite, limestone

Anhydrite, shale, halite

Halite

Anhydrite, limestone, shale

Halite with minor interbeds

Estimated average

Hydraulic 

conductivity 

(foot squared 

per day)

0.000046

(.0004)

.00042

.00065

(.004)

.0041

(.002)

.019

.0051

(.002)

.0030

(.002)

(.003)

.0011

(.002)

.013

(.002)

.0036

'Altitude of Kelly bushing is 4,949.2 feet above NGVD of 1929.

2Unless enclosed in parentheses, value was obtained from a drill-stem test. 

Values in parentheses are estimates based on the median hydraulic conductivity of the rock types in the interval or the measured value for an interval of 

similar lithology in the borehole.

because of its importance as a source of water in the 

Canyonlands region of Utah, as well as in other deeply dissected 

areas of the UCRB.

The Canyonlands aquifer vertically is divisible into three 

zones with different lithologic and hydrologic properties. The 

lowermost zone, the Cutler-Maroon zone, consists mostly of 

interbedded clastic and carbonate rocks and is named after the 

two geologic units within the zone most characteristic of its 

lithology and most often used as sources of water. The middle 

zone, the Weber-De Chelly zone, consists almost entirely of 

quartz sandstone and is named for the two most prominent 

water-bearing formations within this zone. The uppermost 

zone, the Park City-State Bridge zone, consists alternately of 

carbonate rocks, carbonate and clastic rocks, or shale and is 

named for the two geologic units most representative of the 

extensive regional variations in lithology within the uppermost zone.

CUTLER-MAROON ZONE

The Cutler-Maroon zone of the Canyonlands aquifer 

consists of a very thick sequence of variably permeable clastic 

and carbonate rocks of Early Pennsylvanian to Late Permian 

age that are hydraulically connected by fractures associated 

with folds, faults, and igneous intrusions. Component 

geologic units include the Ranchester Limestone Member of 

the Amsden Formation; the upper member of the Hermosa 

Formation; the Gothic, Minturn, Morgan, Rico, Supai, and 

Cutler Formations; the Elephant Canyon Formation, Halgaito 

Shale, Cedar Mesa Sandstone, and Organ Rock Shale of the 

Cutler Group; the Wescogame Formation and Esplanade 

Sandstone of the Supai Group; the main body of the Maroon 

Formation (excluding the Schoolhouse and Fryingpan 

Members); and the Hermit Shale (table 1).

The most permeable component geologic unit is the Cedar 

Mesa Sandstone, which has both intergranular and fracture 

permeability (Richter, 1980, p. 19). The lower 150 feet of this 

formation is the source of numerous small to moderately sized 

springs in the ruggedly dissected Canyonlands area of southeastern Utah (Ritzma and Doelling, 1969, p. 64 65; Sumsion 

and Bolke, 1972, p. 48; Richter, 1980, p. 9-11). The Cedar

TABLE 11. Hydraulic conductivity of the Paradox Member of the 

Hermosa Formation in Borehole DOE-1 (SLD23-20-05badl)

[Slug test data were compiled from Rush and others, 1980. Location of 

borehole shown on plate 4; <, less than]

Interval below 

land surface 

(feet)

626-738

738-771

771-918

918-951

951-1,063

1,063-1,076

1,076-1,187

1,187-1,197

1,197-1,276

31,276-4,276

Lithology

Salt

Interbeds

Salt

Interbeds

Salt

Interbeds

Salt

Interbeds

Salt

Salt with interbeds

Estimated average

Hydraulic 

conductivity 

(feet per day)

'(0.0001)

2(.0003)

'(.0001)

.00033

.00013

.000033

4«.00001)

.00003

'Estimate based on data for interval 951-1,063 feet.

2Estimate based on data for interval 918-951 feet.

3Total thickness estimated from borehole DOE-3 (SLD23-20-05bad). 

This borehole penetrated 3,520 feet of the Paradox Member without reaching 

the base of this unit.

4Estimate based on a slug test in DOE-3 between depths of 728 and 

4,061 feet. The tested interval consisted of salt with interbeds. No systematic 

decline in water level was detected, indicating a very small hydraulic 

conductivity.
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER B89

YIELD, IN GALLONS PER MINUTE

0.10 0.16 0.25 0.40 0.63 1.0 1.6 2.5 4.0 6.3 10 16 25 40 63 100 160 250 400 630 1,000 

20 

18

16

14

12

g,0

-1.0 -0.8 -0.6 -0.4 -0.2 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 

LOG (BASE 10) OF YIELD, IN GALLONS PER MINUTE

2.2 2.4 2.6 2.8 3.0

FIGURE 63. Frequency distribution of yields from the Paradox-Eagle Valley subunit of the Four Corners confining unit.

Mesa Sandstone also yields small to moderate quantities of 

water to wells in the Canyonlands area, including supply wells 

in Canyonlands National Park (Sumsion and Bolke, 1972, 

p. 52) and Natural Bridges National Monument (Huntoon, 

1977, p. 19-20; Hand, 1979, p. 7-8).

Component geologic units of the Cutler-Maroon zone that 

mostly consist of interbedded sandstone and shale are not as 

permeable as the Cedar Mesa Sandstone but supply water 

throughout a much larger area. Within these units, including the 

Minturn Formation, Gothic Formation, Cutler Formation, Supai 

Formation, main body of the Maroon Formation, and the Supai 

Group, generally small to moderate discharges of water to wells 

and springs occur where downward percolation is prevented by 

discontinuous layers of shale, fine-grained sandstone, or 

carbonate rocks. Most of the water transmitted by these 

geologic units is from intervals of sandstone or conglomerate, 

which have both intergranular and fracture permeability. Other 

rock types have mostly fracture or solution permeability (see 

Richter, 1980, p. 13). Of the geologic units comprising this category, the main body of the Maroon Formation is most widely 

used for water supplies (Brodgen and Giles, 1976a; Giles and 

Brogden, 1976; Wright Water Engineers (1979). The Maroon 

Formation is the principal bedrock aquifer supplying water to 

wells in the Roaring Fork Valley between Glenwood Springs

and Aspen, Colo., and is the source of numerous springs in the 

Elk Mountains, including Arsenic Spring (SCI 1-87-35) and 

Conundrum Hot Springs (SCI2-85-16ac). The Minturn 

Formation supplies small quantities of water to wells in the 

McCoy and Minturn areas of Colorado (Colorado Division of 

Water Resources, Office of the State Engineer, unpublished 

well permits). The Gothic Formation supplies small quantities 

of water to springs near Crested Butte, Colo. (Giles, 1980). The 

Cutler Formation supplies small to moderate quantities of water 

to wells and widely scattered springs on the edges of the 

San Juan Mountains and Uncompahgre Plateau and in the 

Paradox Basin (Sumsion, 1971, p. 37-39; Richter, 1980, p. 9, 

20; Whitfield and others, 1983, p. 62-88; U.S. Geological 

Survey, unpublished data). The Supai Group yields small quantities of water to wells and springs in the Defiance Plateau area 

but generally does not transmit water readily (Akers and others, 

1962, p. 3); in the Grand Canyon area, for example, only one 

small spring is known to issue from this unit (Metzger, 1961, 

p. 118).

Component geologic units of the Cutler-Maroon zone that 

consist of interbedded carbonate rocks, sandstone, and shale, 

including the Morgan, Elephant Canyon, and Rico Formations, 

the upper member of the Hermosa Formation, and the 

Ranchester Limestone Member of the Amsden Formation, have
B90 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

little intergranular permeability and transmit water mainly 

through fractures and solution channels (Richter, 1980, p. 13). 

Within these geologic units, sandstone and sandy limestone 

layers are the principal sources of water, particularly where they 

are underlain by shale or fine-grained limestone. Geologic units 

in this category are not often used to obtain water because 

water-bearing properties vary considerably and are unpredictable. The Morgan Formation, for example, generally is not 

water bearing, but it supplies small to large quantities of water 

to springs in the Jones Hole area at the eastern end of the Uinta 

Mountains (Sumsion, 1976, p. 45) where the formation is cut by 

faults and the overlying Weber-De Chelly zone is unsaturated. 

The Elephant Canyon and Rico Formations function mainly as 

a basal confining layer for the Cedar Mesa Sandstone; but in the 

Canyonlands area, small springs issue from fractured limestone 

layers in the upper 50 feet of these formations (Huntoon, 1979; 

Richter, 1980, p. 9). The upper member of the Hermosa 

Fonnation typically supplies small quantities of water to wells 

and springs throughout southeastern Utah and southwestern 

Colorado (Richter, 1980, p. 21-23; Thackston and others, 1981, 

p. 205), but large discharges can occur in fault zones where the 

permeability has been enhanced by fracturing (Huntoon, 1977, 

p. 7 8). According to Lines and Glass (1975), small discharges 

are possible from the Ranchester Limestone Member of the 

Amsden Formation, even though spring discharges are 

unknown, and few water wells are completed in this unit.

Component geologic units of the Cutler-Maroon zone that 

mostly consist of shale and very fine-grained sandstone, 

including the Organ Rock, Halgaito, and Hermit Shales, are 

negligibly permeable, even where transected by fractures. 

These units yield little or no water in most areas, functioning 

mainly as confining layers for the Cedar Mesa Sandstone and 

the Coconino, White Rim, and De Chelly Sandstones of the 

overlying Weber-De Chelly zone (Metzger, 1961, p. 118; 

Richter, 1980, p. 13; Rush and others, 1982, p. 15). However, a 

few small springs are known to issue from the Halgaito Shale in 

the Monument Upwarp (Ritzma and Doelling, 1969, p. 78-79).

The Cutler-Maroon zone has a tendency to produce water 

everywhere that it occurs, but because of thick intervals of 

negligibly permeable rock within this zone, wells hundreds to 

thousands of feet deep may produce little or no water. Because 

the depth at which water will be present in a well and the 

amount of discharge are unpredictable, the Cutler-Maroon zone 

can be expected to function subregionally as an aquifer in the 

UCRB.

THICKNESS AND LITHOLOGY

The thickness of the Cutler-Maroon zone ranges from 0 to 

more than 10,000 ft (fig. 64). Regionally, this zone consists of 

highly variable proportions of sandstone, conglomerate, shale, 

limestone, dolomite, and gypsum-anhydrite as a result of abrupt 

facies changes related to syndepositional uplift and subsidence. 

Sandstone and conglomerate generally make up 50 to more than 

75 percent of the Cutler-Maroon zone within and adjacent to the

Sawatch and Gore Ranges, the Elk and San Juan Mountains, the 

White River, Uncompahgre, Defiance, and Kaibab Plateaus, 

and the Paradox Basin. The sandstone in these areas 

predominantly is red, arkosic, micaceous, coarse grained, and 

friable; most of the interbeds are siltstone or mudstone; 

carbonate intervals are thin and sparsely distributed. Away from 

these areas, the rocks become predominantly gray, green, tan, 

and pink; arkosic sandstone layers become finer grained, more 

indurated, and less numerous; quartz sandstone intervals 

thicken and predominate over arkosic intervals; siltstone and 

mudstone intervals thicken and equal or exceed sandstone in 

abundance; limestone and dolomite intervals thicken and 

compose as much as 45 percent of the zone; thin gypsum or 

anhydrite beds occur locally. In northern and central parts of the 

UCRB, the Cutler-Maroon zone consists of limestone and dolomite with subordinate shale interbeds, generally less than 

25 percent sandstone interbeds, and locally, minor interbeds of 

gypsum or anhydrite. Contacts between component geologic 

units and overlying Pennsylvanian and Permian rocks generally 

are conformable to gradational, but local unconformities exist. 

In southeastern Utah east of the Monument Upwarp and in 

western Colorado south of the Piceance Basin, component 

geologic units of the Cutler-Maroon zone generally are the 

youngest Paleozoic rocks and are overlain conformably to 

unconformably by Mesozoic rocks.

POROSITY AND PERMEABILITY

The porosity of the Cutler-Maroon zone varies considerably 

from place to place and within vertical sequences because of 

extreme variations in lithology. Sandstone is the most porous 

rock type within this zone. In 299 analyses, sandstone porosity 

ranged from 0.8 to about 20 percent, with a median value of 

9.1 percent (fig. 65). The median porosity of sandstone varieties 

generally increases with decreasing cement and clay content 

and increasing grain size (table 12). Limestone and dolomite, on 

the average, are about one-third as porous as sandstone. In 

210 analyses, the porosity of limestone and dolomite ranged 

from 0.4 to 16 percent, with median values of 2.4 percent for 

limestone and 3.3 percent for dolomite (fig. 65). In 10 analyses, 

shale porosity ranged from 0.5 to about 12 percent, with a 

median value of 4.7 percent, but given the small number of analyses, these figures probably are not statistically significant. On 

the basis of the porosity of shale in all of the hydrogeologic 

units composed of Paleozoic rocks, it is estimated that median 

shale porosity in the Cutler-Maroon zone probably is between 2 

and 4 percent. On the basis of lithologic composition, median 

porosity values for common rock types, and sparsely distributed 

laboratory and geophysically determined site averages, unitaveraged porosity in the Cutler-Maroon zone is estimated to 

range regionally from about 2 to 14 percent (pi. 5).

Borehole geophysical logs show no obvious relation 

between porosity and depth but confirm a strong relation 

between porosity and lithology. In figure 66A, a geophysical log
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER B91

BOUNDARY OF 

UPPER COLORADO -^ 

RIVER BASIN

EXPLANATION

[.' ' '.' ' '.'I Area where Cutler-Maroon zone is 

missing because of erosion or 

nondeposition

Area where Cutler-Maroon zone consists 

of quartzose to arkosic sandstone with 

subordinate conglomerate and shale 

interbeds and minor to subordinate 

carbonate interbeds

Area where Cutler-Maroon zone consists 

of limestone and dolomite with minor 

to subordinate shale, sandstone, and 

gypsum interbeds

Area where Cutler-Maroon zone consists 

of shale with minor to subordinate 

sandstone and carbonate interbeds 

and minor gypsum interbeds

Area where Cutler-Maroon zone consists 

of limestone, dolomite, sandstone, and 

shale

200 Line of equal thickness Interval, in feet, 

is variable

 AREA EXCLUDED 

FROM STUDY

25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 64. Thickness and lilhology of the Cutler-Maroon zone of the Canyonlands aquifer. 

(Modified from Geldon, in press, pi. 15.)
B92 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

SANDSTONE 

Red (mostly arkosic)

Light-colored (mostly 

quartzose)

01234567 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 

POROSITY, IN PERCENT

70

60

50

> 40

O

LU 

K.

\ \ \

20

10

/Z.

CARBONATE ROCKS

Y//y/\ Dolomite 

Limestone

I I

012345 7 8 9 10 11 12 13 14 15 16 17 18 19 20 

POROSITY, IN PERCENT

FIGURE 65. Frequency distribution of porosity in samples of sandstone and carbonate rocks 

from the Cutler-Maroon zone of the Canyonlands aquifer.
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER B93

TABLE 12. Porosity and pore-scale permeability statistics for the Cutler-Maroon zone of the Canyonlands aquifer

[<, less than]

Rock type

Sandstone

Limy

Shaly

Friable

Silty

Fine grained

Medium grained

Coarse grained

Gravelly

Mostly arkosic 

(red-colored)

Mostly quartzose 

(light-colored)

All

Limestone

Dolomite

Shale

Minimum

1.2

1.2

5.8

.8

1.2

5.1

6.3

9.2

1.4

.8

.8

.4

.7

.5

Porosity 

(percent)

Maximum

6.7

20.4

18.2

17.9

20.4

14.9

18.6

18.9

20.4

20.0

20.4

16.0

14.0

11.9

Median

5.0

6.2

12.1

4.5

6.4

9.2

15.4

13.7

11.6

7.3

9.1

2.4

3.3

4.7

Number of 

observations

8

56

11

51

62

32

27

21

153

145

299

194

16

10

Pore-scale permeability 

(millidarcies)

Minimum Maximum

<0.01 <0.01

<.OI 5.2

<.01 34

<.01 8.9

<.01 27

<.01 5.2

.02 232

<.l 45

<.01 232

.0007 1 27

.00071 232

<.01 120

<.01 .98

<.01 .30

Median

<0.01

<.01

2.5

.09

<01

<.l

6.0

6.7

2.0

.01

.46

.01

.04

<.01

Number of 

observations

8

56

II

51

62

32

27

21

153

145

299

194

16

10

in a borehole drilled into the Cutler Formation, variations in 

porosity reflect the alternation of arkosic sandstone and shale 

intervals. However, individual sandstone or shale intervals 

cannot be distinguished. In figure 66B, a geophysical log in a 

borehole drilled into the Cedar Mesa Sandstone, intervals of 

siltstone or siltstone and quartz sandstone are distinctly less 

porous than intervals of quartz sandstone. In figure 66C, a 

geophysical log in a borehole drilled through several formations 

of different lithology, formation tops are clearly visible on the 

basis of changes in porosity. A distinct increase in porosity 

occurs at the contact between the Organ Rock Shale and the 

Cedar Mesa Sandstone. A distinct decrease occurs at the contact 

between the Cedar Mesa Sandstone and the lithologically 

diverse Elephant Canyon Formation. Within the lower formation, intervals of quartz sandstone or sandstone with limestone 

clearly are more porous than intervals of sandstone and siltstone 

or sandstone and dolomite. Carbonate intervals are the least 

porous. Variations in the porosity of sandstone in the Cedar 

Mesa Sandstone and Elephant Canyon Formation probably are 

attributable to variations in grain size and the amount of 

carbonate or silica cement.

Like porosity, pore-scale permeability in the Cutler-Maroon 

zone varies with lithology (table 12). In 299 analyses, the porescale permeability of sandstone ranged from 0.00071 to 232 md 

and generally increased with decreasing cement and clay 

content and increasing grain size (table 12). In 210 analyses, the 

pore-scale permeability of carbonate rocks ranged from less

than 0.01 to 120 md and, on the average, was about an order of 

magnitude smaller than for sandstone. In 10 analyses, the porescale permeability of shale ranged from less than 0.01 to 

0.30 md and was much smaller, on the average, than for all other 

rock types. Although median values of pore-scale permeability 

increase in about the same manner as median values of porosity 

for varieties of sandstone and carbonate rocks, a relation 

between the two properties appears to exist only for sandstone 

(table 3). As seen in figure 67, even this relationship is vaguely 

defined.

Local-scale permeability in the Cutler-Maroon zone 

depends not only on lithology but also on structural setting. In 

71 determinations, local-scale permeability ranged from 

0.00078 to 68 md, with a median value of 1.5 md (fig. 68). Intervals composed entirely of either sandstone or carbonate rocks 

were found to be more permeable than intervals containing 

shale interbeds. No significant differences in local-scale permeability were detected between sandstone and carbonate intervals. This indicates that secondary openings, such as fractures 

and solution channels, enhance the relatively small pore-scale 

permeability of carbonate rocks. Because secondary openings 

increase and cementation decreases toward uplifted areas, localscale permeability of the Cutler-Maroon zone increases from 

structural basins to uplifted areas (fig. 69). In the Paradox Basin, 

local-scale permeability also appears to be affected by the 

northwest-trending anticlines and grabens that characterize the 

area.
SURFACE LAND BELOW FEET, IN DEPTH, 

Tl 

O

I o X) -h 

2L 3" 

P re el

^« s^

S

o 

EL

PS

. § 8

3

tg.

» £ ^ ^ 2. P |'i

p ^i 

3 3" 

.

8- PJ

g I 

o £' 

o a 

O p 

3 1 

-a 3 o - 

3 > 

O 

UQ

SANDSTONE MESA CEDAR 

I I I ! I 

CANYON ELEPHANT 

FORMATION

nvNOioan waisAS-HHdinov HHddn SISAIVNV oav>ioiO3 HHAIH 'Misva ONiarmxn am NVS Nvnr Nisva 
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER B95

1,000

100

10

o

DC

5 0.1

cc

LU 

Q0.01

0.001

0.0001

n r 

«

10 15 

POROSITY, IN PERCENT

20 25

FIGURE 67. Relation of porosity to pore-scale permeability in sandstone samples from the Cutler-Maroon zone of the Canyonlands 

aquifer.

HYDRAULIC CONDUCTIVITY AND TRANSMISSIVITY

Hydraulic conductivity in the Cutler-Maroon zone, like 

local-scale permeability, ranges from small to large depending 

on lithology and structural setting. In 224 determinations 

(132 pressure-injection tests, 10 pumping tests, 6 bailing tests, 

2 airlift tests, and 74 conversions from permeability or porosity 

determined by drill-stem tests, in the laboratory, or by geophysical methods), hydraulic-conductivity values ranged from 

0.000002 to 10 ft/d (fig. 70), with a median value of 0.15 ft/d. 

Injection tests of the Maroon and Morgan Formations by the 

Bureau of Reclamation at four sites in northwestern Colorado 

indicated values of hydraulic conductivity that ranged from 

0.037 to 4.6 ft/d (table 13). In these tests, sandstone intervals 

generally were more permeable than shale or limestone intervals, with many limestone and shale intervals taking in little or 

no water. Considerable variation in hydraulic conductivity 

among intervals with similar lithology may be related to the 

degree of fracturing, but there is no consistent variation in 

hydraulic conductivity with depth below land surface (fig. 71). 

The median hydraulic conductivity from 70 tests in five boreholes at the Ruedi Dam site, 0.76 ft/d, is very close to the 

hydraulic conductivity determined from a plot of residual

drawdown with time during a bailing test of another borehole at 

the Ruedi Dam site. The data from this test (fig. 72) indicated 

the following:

Discharge = 40° gal = 4.6 gal/min; 

87 mm

~ . . .. 35.2 x 4.6 gal/min Transmissmty = (64g _ 3g92)ft

= 63 ft2/d; and

Hydraulic conductivity = (63 ft /d)/64 ft = 0.98 ft/d.

The injection and bailing tests, together, indicate an average 

hydraulic conductivity of about 0.9 ft/d for the 3,400-ft-thick 

section of the Cutler-Maroon zone at Ruedi Dam.

On the Monument Upwarp, four aquifer tests of the Cedar 

Mesa Sandstone and underlying formations composed of 

carbonate and clastic rocks indicated hydraulic-conductivity 

values ranging from 0.0011 to 0.027 ft/d (based on data reported 

byHuntoon, 1977, p. 19; Hand, 1979, p. 13; Hood and Daniel son, 

1981, p. 64-65; Woodward-Clyde Consultants, Inc., 1982, 

table 9-2; and Thackston and others, 1984, p. 26). However, an 

aquifer test of the Cedar Mesa Sandstone, alone, indicated a 

hydraulic-conductivity value of 2.5 ft/d (Richter, 1980, p. 18). 

The five aquifer tests on the Monument Upwarp, as in northwestern Colorado, indicate that shale and carbonate interbeds in 

the Cutler-Maroon zone have less potential to transmit water than 

sandstone.

Ranging from 0.001 to 10 ft/d, median values of hydraulic 

conductivity for sites on the Monument Upwarp and in 

northwestern Colorado define fairly well the range in unitaveraged hydraulic conductivity typical of uplifted areas. In 

contrast, drill-stem tests in structural basins generally indicate 

values of unit-averaged hydraulic conductivity ranging from 

0.00005 to 0.001 ft/d (pi. 5). Only in the vicinity of fold axes, 

faults, and igneous intrusions do values of unit-averaged 

hydraulic conductivity in structural basins approach those 

recorded in uplifted areas. In the structurally complex Paradox 

Basin, for example, unit-averaged hydraulic-conductivity 

values of 0.003 to 0.02 ft/d have been obtained from drill-stem 

tests (pi. 5).

The composite transmissivity of the Cutler-Maroon zone 

conforms to the distribution of hydraulic conductivity, being 

larger in uplifted areas than in structural basins. Regionally, transmissivity is known from 13 widely scattered aquifer tests to range 

from 0.005 to about 900 ft2/d (pi. 6). These 13 values and regional 

distributions of unit-averaged hydraulic conductivity and thickness indicate the composite transmissivity of the Cutler-Maroon 

zone probably ranges from less than 0.001 to greater than 

1,000 ft2/d (pi. 6). The Cutler-Maroon zone appears to be the
B96 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

PERMEABILITY, IN MILLIDARCIES

0.0001 0.00032 0.001 0.0032 0.01 0.032 0.1 0.32 1.0 3.2 

20

320 1,000

Other

Limestone and dolomite 

Carbonate rocks and shale 

Shale

Sandstone and shale 

SS'Si-l Sandstone

-4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0 0.5 1.0 

LOG (BASE 10) OF PERMEABILITY, IN MILLIDARCIES

FIGURE 68. Frequency distribution of local-scale permeability in the 

Cutler-Maroon zone of the Canyonlands aquifer.

2.5 3.0

most transmissive at the southern end of the Park Range, from the 

Sawatch Range and White River Plateau to the Axial Basin Arch 

and Uinta Mountains, in the Circle Cliffs Uplift the Abajo 

Mountains, and La Sal Mountains, and from the Monument 

Upwarp to the Chuska Mountains and Defiance Plateau.

YIELDS FROM WELLS AND SPRINGS

Yields from the Cutler-Maroon zone of the Canyonlands 

aquifer are small to moderate in most areas (pi. 6). In 175 determinations, artesian discharges from wells and springs ranged 

from 0.1 to 900 gal/min, with a median value of 6.7 gal/min 

(fig- 73).

The smallest discharges from the Cutler-Maroon zone 

consistently occur in structural basins; discharges from wells in 

these areas rarely exceed 10 gal/min. In the Paradox Basin, 

however, fractures associated with faulting, folding, and 

igneous intrusion locally have enhanced permeability, making 

yields from wells and springs of 10 to 300 gal/min possible. In 

the Henry Mountains and Blanding Basins and on the Four 

Corners Platform, fractures associated with igneous intrusions 

locally make yields of 10 to 50 gal/min possible from wells.

The largest discharges from the Cutler-Maroon zone 

consistently occur in uplifted areas, where fracturing, karst 

development, and weathering of cementing minerals from

sandstone have enhanced permeability. In the Needles Fault 

Zone on the Monument Upwarp, for example, discharges from 

wells and springs, including Big Spring (SLD32-18-29dbd), 

commonly range from 50 to 125 gal/min (Huntoon, 1979, 

p. 43). On the White River Plateau and in the Elk and Uinta 

Mountains, springs with discharges of 50 to 100 gal/min, 

such as Dutch Spring (SC03-92-08bdc), Cold Iron Spring 

(SC10-88-04), and Burnt Springs (SB07-104-13bca), are not 

uncommon (lorns and others, 1964; Sumsion, 1976; Teller and 

Welder, 1983), and springs with discharges of 400 to 

900 gal/min, such as Stump Spring (SC03-92-23baa), 

Mitten Fault Spring (SB07-103-20dbc), and Arsenic Spring 

(SCI 1-87-35), can occur near faults (Rouse, 1967; Sumsion, 

1976; Teller and Welder, 1983). The water from these large 

fault-controlled springs may be partly derived from 

Mississippian carbonate rocks affected by the faults. 

Numerous springs issuing from the Cutler-Maroon zone in 

Jones Hole (SLD03-25-01b) in the eastern Uinta Mountains, 

have a combined discharge of 16,650 gal/min (Hood, 1976, 

p. 34 35). However, these springs result more from draining 

of the entire Canyonlands aquifer into a topographic sink than 

from the transmissivity of the Cutler-Maroon zone alone. 

Under normal conditions, discharges from the Cutler-Maroon 

zone to wells and springs are not likely to exceed 900 gal/min.
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER B97

110

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

Uplifted area

CU -Circle Cliffs Uplift

SC San Rafael Swell and Capitol Reef

fold and fault belt 

MU Monument Upwarp 

SM San Juan Mountains 

UP Uncompahgre Plateau

Structural basin

HP -- High Plateaus region

KP Kaiparowits Basin

HB Henry Mountains Basin

PB Paradox Basin

BT Blanding Basin and Tyende Saddle

FP Four Comers platform

 0. 1 Line of equal local-scale sandstone

permeability Location is approximate. 

Interval, in millidarcies, is variable

 Boundary of uplifted area or structural 

basin

2.5

Data sites Number is local-scale sandstone 

permeability, in millidarcies

Calculated from mean pore-scale 

permeability in a borehole interval

Calculated from mean pore-scale 

permeability of samples from an outcrop 

(reported by Jobin, 1962. p. 145 146)

Calculated from mean porosity in a borehole 

interval

Determined by a drill-stem test

 AREA EXCLUDED 

FROM STUDY

100 MILES

_I

0 25 50 75 100 KILOMETERS

FIGURE 69. Distribution of local-scale sandstone permeability in the Cutler-Maroon zone of the Canyonlands 

aquifer in southeastern Utah and southwestern Colorado.
B98 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING THE SAN JUAN BASIN

HYDRAULIC CONDUCTIVITY, IN FEET PER DAY 

0.000001 0.0000032 0.00001 0.000032 0.0001 0.00032 0.001 0.0032 0.01 0.032 0.1 0.32

45

1.0 3.2 10

40

35

30

25

O

20

15

10

5 -

|____ Other

____ Limestone and dolomite 

Kx\\N Carbonate rocks and shale 

| ] Shale

Sandstone and shale 

Nx:'i-'"fi'-:.' Sandstone ± minor shale

0

-6.0 -5.5 -5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0 0.5 1.0

LOG (BASE 10) OF HYDRAULIC CONDUCTIVITY, IN FEET PER DAY

FIGURE 70. Frequency distribution of hydraulic conductivity in the Culler-Maroon zone of the Canyonlands aquifer.
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER B99

TABLE 13. Values of hydraulic conductivity in the Cutler-Maroon zone of the Camonlands aquifer determined b\ pressure-injection tests

at dam sites in northwestern Colorado

[Data are from Bureau of Reclamation, written commun.. 1983-85]

Location

SC08-84-l8bab

SC08-84-l8bad

SC08-84-07cdc,

SC08-84-07cdc2

SC08-84-I8bah

SC01-9]-]8acb

SC01-9l-18bdd

SBOI-91-31baC]

SB01-91-3lbac3

Sb()6-94-18dba

Sb06-94-18acd

Borehole

DH-30

DH-31

DH-50

DH-51

DH-1000

DH-2

DH^4

DH-1

DH-2

DH-J

DH-7

Interval below 

land surface 

(feet)

Top

2

4

6

2

35

110

8

9(1

110

14

11

Bottom

300

36

86

100

1,001

212

243

260

150

261

313

Formation Rock types

Maroon

Maroon

Maroon

Maroon

Maroon

Maroon

Maroon

Maroon

Maroon

Morgan

Morgan

Ruedi Dam site

Sandstone with shale

Sandstone with shale

Sandstone with shale

Sandstone with shale

Sandstone with shale

Lake Avery Dam site

Sandstone with siltstone

Sandstone with siltstone

Sawmill Mountain Dam site

Sandstone with siltstone

Sandstone with mudstone

Juniper Mountain Dam site

Limestone and shale

Limestone, shale, and sandstone

Hydraulic conductivity 

(feet per day)

Minimum

0.12

.60

.21

1.3

.043

.072

.081

.92

1.8

.069

.037

Maximum

4.6

3.0

4.2

4.4

1.5

.85

.73

2.7

3.7

1.2

.94

Median

0.86

.90

1.0

3.0

.062

.20

.25

2.2

2.9

.20

.21

Mean

1.1

1.1

1.5

2.9

.23

.27

.32

2.0

2.8

.41

.41

Number 

of tests

19

18

5

4

25

9

14

17

8

7

6

WEBER-DE CHELLY ZONE

The Weber-De Chelly zone of the Canyonlands aquifer 

consists of the Wells Formation, Tensleep Sandstone. Weber 

Sandstone, White Rim Sandstone, De Chelly Sandstone, 

Coconino Sandstone, and the Schoolhouse and Fryingpan 

Members of the Maroon Formation (table 1). Component 

geologic units are Middle Pennsylvanian to Early Permian in 

age. Regionally composed mostly of well-sorted quartz sandstone, the Weber-De Chelly zone generally has at least some 

intergranular permeability and is capable of yielding small to 

moderate supplies of water to wells and springs nearly everywhere the zone is present. Component geologic units, such as 

the Tensleep Sandstone in the Rawlins Uplift (Berry, 1960), 

the Wells Formation in the Overthrust Belt (Lines and Glass, 

1975), the Weber Sandstone in the eastern Uinta Mountains 

(Sumsion, 1976), and the De Chelly Sandstone in the Defiance 

Plateau and Chuska Mountains (Harshbarger and Repenning, 

1954; Cooley and others, 1969), commonly are used to supply 

water to wells. However, these geologic units are so permeable 

that they may be nearly or entirely drained where they crop out 

in uplifted areas and are relatively thin (Metzger, 1961; 

Cooley and others, 1969; Sumsion and Bolke, 1972). In many 

of these uplifted areas, the only water supplies from the 

Weber-De Chelly zone are obtained from the bottom few feet, 

where downward-percolating meteoric water has ponded 

above less permeable shale or carbonate layers in the underlying Cutler-Maroon zone. The proportion of the UCRB

where the Weber-De Chelly zone is unsaturated is relatively 

small and, therefore, the hydrogeologic unit can be expected 

to function as an aquifer throughout most of the UCRB.

THICKNESS AND LITHOLOGY

The thickness of the Weber-De Chelly zone ranges from 0 

to about 4.000 ft (fig. 74). Over most of the UCRB, this hydrogeologic unit consists of light-colored quartz sandstone with 

generally thin interbeds of siltstone, mudstone, limestone, 

dolomite, and anhydrite that comprise no more than 10 percent 

of the thickness. However, carbonate rocks constitute 10 to 

30 percent of the Weber-De Chelly zone on the western edge 

of the UCRB, from the Wasatch Plateau north to the 

Overthrust Belt, and in parts of the Green River and Great 

Divide Basins. Shale layers constitute as much as 30 percent 

of the Weber-De Chelly zone near its eastern and western 

depositional edges in Colorado, Utah, and New Mexico. 

Gypsum and anhydrite account for 5 to 10 percent of the 

Weber-De Chelly zone in a small area north and west of the 

Rock Springs Uplift. Contacts between component geologic 

units and overlying formations of Permian and Triassic age are 

gradational to unconformable.

POROSITY AND PERMEABILITY

Because it predominantly consists of well-sorted quartz 

sandstone, the Weber-De Chelly zone consistently is more 

porous than any other hydrogeologic unit in the UCRB. In 

2,618 analyses, sandstone porosity ranged from less than 0.1 to
BIOO REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN. EXCLUDING SAN JUAN BASIN

1 1 II II IT H 1

TALUS , i 

_ DH-1 (SB01-91-31bac,) r ' 

WEBER SANDSTONE f 

MAROON FORMATION /

^

II I I I I II I

Gravel, cobbles and 

boulders

Very fractured, finegrained quartz 

sandstone

Fine-grained sandstone

Fine to coarse sandstone

Very fractured, finegrained arkosic 

sandstone

Very fractured siltstone

Very fractured, finegrained sandstone

50

100

150

200

250

300

0.1 1.0 10 100 1,000

50

100

150

200

250

< 300

DH-1000 (SC08-8418bab)

MAROON 

FORMATION

Fine-grained arkosic 

sandstone

Sandstone and shale

Fine- to coarse-grained sandstone

Fine-to medium-grained

arkosic sandstone

and shale

0.01

25

0.1 1.0 10

50

100

150

200

250

i 1 1 1 1

DH-62 (SC08-84-17bac2> r ~

MINTURN H 

FORMATION I

[ ~

 P

II ! I I I I

Sandstone and siltstone

Sandstone, siltstone, mudstone

Siltstone

Siltstone and mudstone

Mudstone

0.1 1.0 10

I I I I I II

DH-7 (SB06-94-18acd)

50

100

150

200

250

300

350

Fine-grained limestone with scattered 

shale interbeds and sparse joints

Sandy mudstone

MORGAN FORMATION

Fine-grained sandstone and mudstone

Fractured mudstone

I I I I I I

0.001 0.01 0.1 

HYDRAULIC CONDUCTIVITY, IN FEET PER DAY

1.0

FIGURE 71. Relation of hydraulic conductivity to depth below land surface and lithology in component geologic units of the CutlerMaroon zone of the Canyonlands aquifer in northwestern Colorado (hydraulic-conductivity values from injection-test data furnished 

by Bureau of Reclamation, written commun., 1983-85).
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER B101

8.0

7.5

7.0

6.5

Z 6.0

o

Q

1

<r

Q 

I

(75

LU

<r

5.5

5.0

4.5

4.0

3.5

3.0

\ \

_L _L

6 7 8 9 10

TIME SINCE BAILING STARTED

TIME SINCE BAILING STOPPED

20 30 40 50 60 70 80 90100

FIGURE 72. Residual drawdown in well DH-16 (SC08-84-07bdc) at Ruedi Dam site, Colorado, during bailing test 

of Maroon Formation in April 1963 (data from Bureau of Reclamation, written conimun., 1985).

27.7 percent, with a median value of 8.0 percent (fig. 75). 

Friable, micaceous, and shaly varieties were found to be more 

porous than indurated (limy or quartzitic) varieties; coarsegrained sandstone was found to be more porous than very finegrained (silty), fine-grained, and medium-grained varieties 

(table 14). Though few in number, analyses of porosity in shale, 

carbonate rocks, and anhydrite indicate that these rock types, on 

the average, are less porous than sandstone in this hydrogeologic unit (table 14).

Borehole geophysical logs confirm that considerable variations in porosity can result from variations in sandstone texture 

and the presence of shale, carbonate, or evaporite interbeds. In 

figure 76A, for example, porosity in the Tensleep Sandstone at 

a site on the northern edge of the Great Divide Basin ranges 

from about 1 to 15 percent, probably reflecting variations in the 

amount of silica and carbonate cement; the relatively small 

porosity between depths of 4,810 and 4,850 ft probably indicates dolomite interbeds. In figure 16B, porosity in the Weber

Sandstone at a site on the Axial Basin Arch ranges from about 

3 to 15 percent, again probably reflecting variations in the 

degree of cementation and also the presence of siltstone and 

feldspathic sandstone interbeds. In figure 76C, porosity in the 

White Rim Sandstone at a site at the eastern edge of the 

San Rafael Swell ranges mostly from 11 to 15 percent, probably 

reflecting generally uniform grain size and cementation; intervals of small porosity between depths of 2,450 and 2,525 ft and 

at depths of about 2,900 and 3,025 ft probably indicate that 

carbonate or shale interbeds are present. In figure 76/3, the 

porosity of the De Chelly Sandstone at a site on the western 

edge of the Monument Upwarp ranges from less than 1 to about 

5 percent, indicative of considerable induration and, probably, 

interstitial clay and feldspar minerals that typically are present 

in this formation. Representative of vertical variations in 

porosity regionwide, these four examples emphasize the importance of sandstone texture in determining unit-averaged 

porosity.
B102 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

YIELD, IN GALLONS PER MINUTE 

0.10 0.16 0.25 0.40 0.63 1.0 1.6 2.5 4.0 6.3 10 16 25 40 63 100 160 250 400 630 1,000

30 | 

-1.0 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0

LOG (BASE 10) OF YIELD, IN GALLONS PER MINUTE

FIGURE 73. Frequency distribution of yields from the Cutler-Maroon zone of the Canyonlands aquifer.

The largest values of unit-averaged porosity in the WeberDe Chelly zone occur in uplifted areas, where sandstone 

outcrops and subcrops commonly are leached of cementing 

minerals. In the Uinta Mountains, San Rafael Swell, Defiance 

Plateau, and San Francisco Plateau (a physical feature shown on 

pi. 1 that is beyond the political boundaries of the UCRB but 

within the boundaries of the ground-water system), the average 

porosity at outcrops of the Weber, White Rim, De Chelly, and 

Coconino Sandstones ranges from 11 to 28 percent (data from 

Cooley and others, 1969, p. 46-47, pi. 5; Hood, 1976, p. 31; and 

Hood and Patterson, 1984, p. 62-63). Unit-averaged porosity in 

this zone decreases substantially away from outcrop areas, as 

sandstone layers become more firmly cemented by silica and 

carbonate minerals precipitated from ground water (Bredehoeft, 

1964; Fox and others, 1975). In the greater Green River Basin,

the unit-averaged porosity of the Tensleep Sandstone, Weber 

Sandstone, and Wells Formation decreases from more than 15 

to less than 5 percent toward the interior of the basin (Fox and 

others, 1975). On the basis of a large, regionwide distribution of 

geophysical and laboratory measurements of porosity and estimates of porosity from pore-scale permeability (using an equation given in table 3), it is estimated that unit-averaged porosity 

in the Weber-De Chelly zone ranges regionally from about 1 to 

28 percent, increasing from structural basins to uplifted areas 

(pi. 7).

Permeability in the Weber-De Chelly zone also depends on 

lithology and structural setting and ranges from small to large. 

Pore-scale permeability in 2,618 analyses of sandstone ranged 

from less than 0.01 to 2.115 md, with a median value of 0.40 md 

(table 14). Local-scale permeability in 127 determinations
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER B103

BOUNDARY OF 

UPPER COLORADO 

RIVER BASIN

_ -. .V-'-' O

 . '. . '. .-V/.'-'pfi^^-v:-'.-. Landei

Rock Springs

WYOMING

EXPLANATION

Area where Weber-De Chelly zone is 

missing because of erosion or 

nondeposition

Area where Weber-De Chelly zone 

consists of quartz sandstone with 

conglomerate layers and less than 

10 percent shale and carbonate 

interbeds

Area where Weber-De Chelly zone 

consists of quartz sandstone with 10 

to 30 percent shale interbeds

Area where Weber-De Chelly zone 

consists of quartz sandstone with 10 

to 30 percent limestone and dolomite 

interbeds

 200 Line of equal thickness Interval is 200 

feet, except in Strawberry valley area 

(northwest of Price, Utah), where interval 

is 2,000 feet

 AREA EXCLUDED 

FROM STUDY

25 50 75 100 MILES

 i '

0 25 50 75 100 KILOMETERS

FIGURE 74. Thickness and lithology of the Weber-De Chelly zone of the Canyonlands aquifer. 

(Modified from Geldon, in press, plate 16.)
B104 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

300 r

250

200

> 

o

Z> 150 

O

100

50

0 L01234567 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 25 25 26 27 28 

POROSITY, IN PERCENT

FIGURE 75. Frequency distribution of porosity in samples ol sandstone from the Weber-De Chelly zone of the Canyonlands aquifer.

ranged from 0.014 to 380 md, with a median value of 0.96 md 

(fig. 77). As indicated in table 14, friable and shaly varieties of 

sandstone, on the average, are more permeable than indurated 

(limy or quartzitic) varieties. Because grain size and cementation are two of the three factors that determine porosity (the 

other being sorting), it is not surprising that pore-scale permeability in the Webcr-De Chelly zone is closely related to 

porosity (fig. 78 and table 3). Permeability variations not attributable to porosity probably can be explained by varying degrees 

of fracturing (Berry, 1960; Mctzger. 1961; Akers and others, 

1962; Whitcomb and Lowry, 1968; Sutnsion and Bolke, 1972; 

Lines and Glass, 1975; Hood, 1976). Because fracturing 

increases and cementation decreases toward uplifted areas, the 

Weber-De Chelly zone generally is more permeable in uplifted 

areas than in structural basins (fig. 79).

HYDRAULIC CONDUCTIVITY, TRANSMISSIVITY, 

AND STORATIVITY

The hydraulic conductivity of the Weber-De Chelly zone 

commonly is small to moderate, but within and on the margins 

of uplifted areas (down hydraulic gradients from unsaturatcd 

outcrops), the hydraulic conductivity can be large. Hydraulic 

conductivity in 169 aquifer tests and calculations from localscale permeability ranged from 0.000034 to 61 ft/d, with a 

median value of 0.012 ft/d (fig. 80). Values of hydraulic 

conductivity determined from pumping, flowing-well, and 

pressure-injection tests in and near uplifted areas ranged from 

0.01 to 20 ft/d (table 15), whereas values determined from 

40 drill-stem tests in basins or on the margins between basins 

and uplifts ranged from 0.000034 to 0.92 ft/d. On the basis of a 

large number of porosity, permeability, hydraulic conductivity,
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER B105

and transmissivity determinations, it is estimated that the unitaveraged hydraulic conductivity of the Weber-De Chelly zone 

ranges regionally from 0.00005 to 20 ft/d, increasing from 

structural basins to uplifted areas (pi. 7).

The composite transmissivity of the Weber-De Chelly zone, 

as indicated by aquifer tests listed in table 15 and regional distributions of thickness and unit-averaged hydraulic conductivity, 

is estimated to range from 0.01 to 6,000 ft2/d (pi. 8). Values of 

less than 1 fr/d typically occur in structural basins, whereas 

aquifer tests in uplifted areas commonly indicate transmissivity 

values of 100 to more than 1,000 ft2/d. The largest value of 

transmissivity in the Weber-De Chelly zone, 6,000 ft2/d, was 

estimated from the specific capacity determined during a 

pumping test of the Weber Sandstone at the western end of the 

Uinta Mountains. That this value is at least the right order of 

magnitude is indicated by two conventionally analyzed aquifer 

tests of the Weber Sandstone in the eastern Uinta Mountains 

analyzed using standard methods. These tests indicated transmissivity values ranging from 1,400 to 4,000 fr/d.

The storativity of the Weber-De Chelly zone was estimated 

on the basis of regional distributions in thickness and unitaveraged porosity, using equation 22. Where the aquifer is more 

than 100 ft thick, the storativity was estimated to range from 

less than 0.0001 to 0.0013 (fig. 81).

YIELDS FROM WELLS AND SPRINGS

Yields from the Weber-De Chelly zone are small to 

moderate in most areas (pi. 8). In 177 determinations, artesian 

yields from wells and springs ranged from 0.1 to 2,200 gal/min,

with a median value of 16 gal/min (fig. 82). With permeability 

reduced by cementation in structural basins, wells in these areas 

typically yield less than 25 gal/min. In uplifted areas where 

formations that comprise the Weber-De Chelly zone crop out, 

only the base of these formations may be saturated, and in these 

areas, springs issuing from the saturated zone typically have 

discharges of 0.1 to 5 gal/min. In uplifted areas where the 

component geologic units are buried, moderate to large 

discharges are possible. Olson Spring (SB23-88-20aaa), for 

example, issues from the Tensleep Sandstone in the Rawlins 

Uplift at a rate of 200 gal/min (Berry. 1960. p. 50-51). Echo 

Park well no. 3 (SB07-103-32adb) flows water from the Weber 

Sandstone in the eastern Uinta Mountains at rates of 35 to 

150 gal/min (Sumsion, 1976, p. 42^4-5). Large springs, which 

may be related to nearby thrust faults, issue from the Wells 

Formation in the Overthrust Belt (Lines and Glass, 1975) and 

from the Weber Sandstone in the Uinta Mountains (Hood and 

others, 1976; Hood, 1977). Examples include Ratliff Spring 

(SLD02-22-31adc), with a discharge of 1,350 gal/min, Hams 

Fork Spring (SB29-1 1 8-1 3bad), with a discharge of 

1,600 gal/min, and Warm Springs (UB01-08-30ddb), with a 

discharge of 2,200 gal/min.

Faults also appear to be responsible for discharges of 

500 gal/min or more from the Weber-De Chelly zone on the 

flanks of the Wind River Mountains. Kendall Warm Spring 

(SB39-110-36) issues from the Phosphoria Formation on the 

northwestern flank of these mountains at a rate of about 

2,900 gal/min. Because such large discharges are not typical

TABLE 14. Porosity and pore-scale permeability statistics for the Weber-De Chelly zone of the Canyonlands aquifer

[<, less than]

Rock type

Sandstone

Limy or quar&itic

Anhydritic

Micaceous

Friable

Shaly

Very fine grained

Fine grained

Medium grained

Coarse grained 

to gravelly

All

Shale

Limestone and 

dolomite

Anhydrite

Minimum

<0.1

3.8

4.9

2.7

1.8

<.l

.3

.7

<.l

4.6

.6

2.7

Porosity 

(percent)

Maximum

21.8

7.9

16.2

14.6

25.0

19.9

27.6

27.7

20.7

27.7

11.2

6.0

2.7

Median

2.0

5.7

8.3

9.4

10.4

7.0

6.4

5.9

11.4

8.0

6.8

1.4

2.7

Number of 

observations

735

7

27

36

155

161

1,408

461

23

2,618

8

8

1

Pore-scale permeabil 

(millidarcies)

Minimum Maximum

<0.01 970

<.()! .30

<.01 3.2

<.0 1 30.0

<01 933

.01 35

<.()! 2,115

<.()! 1.780

<.()! 1.364

<.01 2,115

<.01 .25

<.01 .24

<.01 <01

ity

Median

0.03

<.01

<.01

1.8

.88

.12

.15

.10

2.6

.40

<.01

.01

<.01

Number of 

observations

735

7

27

36

155

161

1,408

461

23

2,618

8

8

1
60

S

A. TENSLEEP SANDSTONE 

(SB26-90-11)

R WEBER 

SANDSTONE 

(SB02-98-10)

15 6,47 5 L 20 0 3,075 10 15 20 0 5

POROSITY, IN PERCENT

C. WHITE RUM 

SANDSTONE 

(SLD24-13-11)

7,550

_ 7,600 /-

7,650 - D. DE CHELLY SANDSTONE (SLD21-18-23) Sonic log Density log Neutron log

15 7,700 20 0 10 15 20

jo

5O

O

 fl rn50> >  < 0"0

m

73

nO5

JO>D O /oPi 50on 

Zn r

c

D 

O

FIGURE 76. Relation of geophy sically determined porosity to depth below land surface in component geologic units of the Weber-De Chelly zone of the Canyonlands aquifer:

A, Tensleep Sandstone; B, Weber Sandstone; C, White Rim Sandstone: D. De Chelly Sandstone.

z c 

z63I Z
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER BI07

PERMEABILITY, IN MILLIDARCIES

0. 

30

25 

20 

15

10 

5 

n

D1 0.032 0.1 0.32 1.0 3.2 10 32 100 320 1,0

-

-

-

-2.0 -1.5 -1.0 -0.5 0 0.5 1.0 1.5 2.0 2.5 

LOG (BASE 10) OF PERMEABILITY, IN MILLIDARCIES

3.0

FIGURE 77. Frequency distribution of local-scale permeability 

in the Weber-De Chelly zone of the Canyonlands aquifer.

of the Phosphoria Formation, it is presumed that most of the 

water issuing from this spring is produced by the disruption of 

ground-water circulation in the Tensleep Sandstone by the 

Wind River fault, a thrust fault that separates the Wind River 

Mountains from the Green River Basin. Kendall Warm Spring 

is situated right on this fault. Similarly, two flowing wells 

located on a thrust fault on the southeastern flank of the Wind 

River Mountains (SB33-99-35ad and SB33-100-25ca) also 

yield large quantities of water (500-540 gal/min) from the 

Tensleep Sandstone (Whitcomb and Lowry, 1968).

The largest discharges from the Weber-De Chelly zone in the 

UCRB occur from springs downstream from sinks in Mississippian 

carbonate rocks. Such springs, including Dry Fork Springs 

(SLD03-20-05c), Ashley Creek Springs (SLD03-20-01d), and 

Big Brush Creek Springs (SLD02-21-24c), discharge from the 

Weber Sandstone at seasonably variable rates that range from 500 

to 9,000 gal/min (Maxwell and others, 1971; Hood and others, 

1976). However, these discharges arc more a consequence of 

topography than aquifer properties and are unlikely to be produced 

by wells or springs in typical hydrogeologic settings.

PARK CITY-STATE BRIDGE ZONE

The Park City-State Bridge zone of the Canyonlands 

aquifer consists entirely of Permian geologic units, including 

the Phosphoria, Park City, Kaibab, and Toroweap Formations 

and the lower parts of the Goose Egg and State Bridge 

Formations (table 1). Component geologic units generally have 

little intergranular permeability, but secondary permeability is 

imparted by fractures and solution channels. Consequently, 

small to moderate discharges to wells and springs from the Park 

City and Phosphoria Formations can occur in the Overthrust 

Belt (Lines and Glass, 1975) and Uinta Mountains (Hood and 

others, 1976), and small discharges are possible from the 

Toroweap and Kaibab Formations in the San Rafael Swell 

(Hood and Danielson, 1981), Capitol Reef Fold and Fault Belt 

(Marine, 1962), and northern Arizona (Metzger, 1961; Akers, 

1964; Cooley and others, 1969). The State Bridge and Goose 

Egg Formations generally are not water bearing, but even these 

formations can yield small quantities of water to wells and 

springs from laterally persistent beds of sandstone, siltstone, or 

limestone (Berry, 1960; Brogden and Giles, 1976a; Giles and 

Brogden. 1976). Where the Park City-State Bridge zone is

10,000 F

1,000 -

100 -

C/3 

L1J

o

CC 

<

0.01

0.001

10 20 

POROSITY, IN PERCENT

FIGURE 78. Relation of porosity to pore-scale permeability in 

sandstone samples from the Weber-De Chelly zone of the 

Canyonlands aquifer.
BIOS REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

110

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

Area where Weber-De Chelly zone is 

missing because of erosion or 

deposition

Uplifted area

CU Circle Cliffs Uplift

DC Defiance Plateau and Chuska

Mountains

MU Monument Upwarp 

SC Sari Rafael Swell arid Capitol Reef

fold and fault belt

Structural basin

CS Castle Valley Sag and Sari Rafael

Desert

BT Blanding Basin and Tyeride Saddle 

FP Four Corners Platform 

HB Henry Mountains Basin 

HP High Plateaus region 

KB Kaiparowits. Kaibito, and Black

Mesa Basins 

PB Paradox Basin

 W Line of equal unit-averaged porescale permeability Location is 

106 / 4 approximate. Interval, in millidarcies, 

is variable

39

2.7

13

Boundary of uplifted area or structural 

basin

Data sites Number is unit-averaged porescale permeability, in millidarcies

Mean of values for samples from an outcrop

Mean of values for samples from a borehole 

interval

Median of values from a borehole 

geophysical log

Estimated from permeability determined by 

one or more drill-stem tests

AREA EXCLUDED 

FROM STUDY

25

I

100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 79. Estimated distribution of unit-averaged pore-scale permeability in the Weber-De Chelly zone of the Canyonlands 

aquifer in southeastern Utah, northeastern Arizona, and northwestern New Mexico.
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER B109

HYDRAULIC CONDUCTIVITY, IN FEET PER DAY 

0.00001 0.000032 0.0001 0.00032 0.001 0.0032 0.01 0.032 0.1 0.32 1.0 3.2 10 32 100

30

25

20

15

10

5

0

-5

-

0 -4 5 -4 0 -3

 ;

I

.5 -3 .0 -2 5 -2.0 -1 5 -1 .0 -0

-

'

5 0 0.5 0.1 1.5 0.

LOG (BASE 10) OF HYDRAULIC CONDUCTIVITY, IN FEET PER DAY

RGURE 80. Frequency distribution of hydraulic conductivity in the Weber-De Chelly 

zone of the Canyonlands aquifer.

water bearing, it generally is connected hydraulically to the 

underlying Weber-De Chelly zone. In northern Arizona, for 

example, wells commonly are completed in both the Kaibab 

Formation and Coconino Sandstone (Akcrs, 1964). Composed 

largely of shale and other rocks with little permeability over 

large parts of the UCRB and missing because of erosion or 

nondeposition in most of the area south and east of the confluence of the Green and White Rivers (fig. 83), the Park CityState Bridge zone can be expected to function as an aquifer 

subregionally in the UCRB.

THICKNESS AND LITHOLOGY

The thickness of the Park City-State Bridge zone ranges 

from 0 to 800 ft (fig. 83). In Wyoming and northwestern 

Colorado, a facies consisting of red shale with subordinate 

sandstone, gypsum-anhydrite, limestone, and dolomite grades 

westward into a depositional sequence consisting of varying

proportions of limestone, dolomite, greenish-gray to black 

shale, phosphatic shale, phosphorite, chert, and sandstone. To 

the south, in Utah and Arizona, the shale and phosphatic intervals pinch out, and gypsum-anhydrite layers locally account for 

5 to 30 percent of the Park City-State Bridge zone. Geologic 

units in the Park City-State Bridge zone are overlain conformably to unconformably by Triassic formations composed mostly 

of shale.

POROSITY AND PERMEABILITY

Large variations in porosity are exhibited by the diverse 

rock types that compose the Park City-State Bridge zone 

(fig. 84), but sandstone consistently is the most porous rock 

type (table 16). In 32 analyses, sandstone porosity ranged from 

0.7 to 17.9 percent, with a median value of 7.4 percent. In 521 

analyses, dolomite porosity ranged from less than 0.1 to 

22.4 percent, with a median value of 2.1 percent. Median
B110 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

TABLE 15. Values of hydraulic conductivity and transmissivity in the Weber-De Chelly zone of the Canyonlands aquifer determined from 

pumping, flowing-well, and injection tests in the Upper Colorado River Basin and vicinity

[Dashes indicate not applicable; nd indicates no data; (A) indicates approximate]

Test site

Tensleep

area 1

Tensleep

area

Tensleep

area

Sawmill

Mountain

Sawmill

Mountain

Sawmill

Mountain

Echo Park

Big Brush

Creek

Big Brush

Creek

Kamas

area2

Taylor

Canyon

Taylor

Canyon

Taylor

Canyon

Defiance

Plateau

Defiance

Plateau

Defiance

Plateau

Defiance

Plateau

Defiance

Plateau

Defiance

Plateau

Leupp

area3

St. John's

area4

Name

Mills

Davis

Hamilton

Ranch

DH-1

DH-2

DH-3

Well 3

Stauffer

Chemical

Stauffer

Chemical

Unnamed

Well 1

Well 2

Well 3

EPNG

N-1.N-2

Ganado

School

Nazlini 2

10T-239

10T-272

17 wells

Unnamed

237-1

Borehole

Location

SB44-87-08dcd

SB47-89-l.3aab

SB50-90-14bbd

SB01-91-31bacl

SB01-91-31bac3

SB01-91-31bac2

SB07-103-32abd

SLD02-22-29dcd

SLD02-22-32bcb

SLD02-06-16cda

SLD27-1 7.5-01 ddc

SLD27-18-IOaaa

SLD27-18-09baa

GA26-25-16

GA27-26-26C

NB02-09-16b

NB03-10-15

NB05-10-20

GA22-12-12(A)

GA12-28-18(A)

Type

of test

Flow

Flow

Flow

Pressureinjection

do.

do.

Flow

Pumping

Pumping

Pumping

Flow

Pumping

Pumping

Pumping

Pumping

Pumping

Pumping

Pumping

Pumping

Pumping

Pumping

Formation 

tested

Tensleep

Sandstone

Tensleep

Sandstone

Tensleep

Sandstone

Weber

Sandstone

Weber

Sandstone

Weber

Sandstone

Weber

Sandstone

Weber

Sandstone

Weber

Sandstone

Weber

Sandstone

White Rim

Sandstone

White Rim

Sandstone

White Rim

Sandstone

De Chelly

Sandstone

De Chelly

Sandstone

De Chelly

Sandstone

De Chelly

Sandstone

De Chelly

Sandstone

De Chelly

Sandstone

Coconino

Coconino

Sandstone

and Kaibab

Formation

Hydraulic conductivity Transmis- 

(feet per day) sivity

Site Area (feet squared 

average average per day)

nd - 290

nd -- nd 150

nd - 140

2.8-38 10 nd

3.0-61 17 11 nd

3.7-5.6 4.7 nd

17 - - 4,000

.1 - 1.400-2.700

3.0 - 1.6 200

20 - -- 6,000

1.5 - 200

.19 - .72 24

.48 - 80

.2V-.67 40-93

47

.13 - 68

.47 - 89

.20 - .35 100

.067 - 24

.013-3.5 -- 7.5^190

nd - - 4,700

nd - - 3,200

Analytical method 

(if known)

Estimate from

specific capacity

Analysis of

recovery data

Analysis of

recovery data

do.

Estimate from

specific capacity

do.

do.

do.

do.

Estimate from

specific capacity

do.

do.

do.

do.

do.

Computed from

drawdown data

Source of data

Cooley(1985,

p. 39)

do.

do.

Bureau of

Reclamation

(unpublished)

do.

do.

Sumsion(1976,

p. 51-58)

Hood (1976.

p. 53-54)

do.

Hood (1976,

p. 54-56)

Sumsion and

Bolke(1972.

p. 42)

do.

do.

Cooley and

others (1969,

p. 46^7)

do.

do.

do.

do.

Davis and

others (1963);

McGavock

and others

(1966)

Cooley and

others (1969,

p. 46^17)

Akers (1964,

p. 67)

'in Bighorn Basin, about 100 to 130 mi north of Upper Colorado River Basin (location of area shown on pi. 1). 

In Wasatch Range, about 16 mi west of Upper Colorado River Basin (location of area shown on pi. 1). 

3In Lower Colorado River Basin, about 84 mi south of Upper Colorado River Basin (location of area shown on pi. 1). 

4In Lower Colorado River Basin, about 97 mi south of Upper Colorado River Basin (location of area shown on pi. 1).
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER Bill

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

,'."/.' -'/.' | Area where Weber-De Chelly zone is 

missing because of erosion or 

nondeposition

 0.0008 Line of equal estimated Storativity 

Location is approximate. Interval is 

O.OnOl (dimerisionless)

AREA EXCLUDED 

FROM STUDY

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 81. Estimated storativity distribution in the Weber-De Chelly zone of the Canyonlands aquifer.
B112 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVLR BASIN. EXCLUDING SAN JUAN BASIN

YIELD, IN GALLONS PER MINUTE

0.10 0.16 0.25 0.40 0.63 1.0 1.6 2.5 4.0 6.3 10 16 25 40 63 100 160 250 400 6301,0001,6002,5004,000 

30 T T T

25

20

15

a

UJ

cc

10

1.0 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6

LOG (BASE 10) OF YIELD, IN GALLONS PER MINUTE

FIGURE 82. Frequency distribution of yields from the Weber-De Chelly zone of the Canyonlands aquifer.

porosity values for most varieties of dolomite ranged from 1 to 

2 percent, but the median porosity was about 4 percent in shaly 

dolomite and vuggy dolomite and about 10 percent in sandy 

dolomite. Limestone is somewhat more porous than dolomite 

on the average, although maximum values of limestone porosity 

are smaller than maximum values of dolomite porosity. In 

76 analyses, limestone porosity ranged from 1.2 to 9.7 percent, 

with a median value of 3.4 percent. On the basis of three analyses, the porosity of anhydrite and shale appear to be consistent 

with values obtained for these rock types in other hydrogeologic 

units composed of Paleozoic rocks in the UCRB. Thus, median 

anhydrite porosity is estimated to be less than 1 percent, and 

median shale porosity is estimated to be between 2 and 

4 percent. From the distribution of rock types in this hydrogeologic unit, median porosity values for these rock types, and the

mean of laboratory-determined porosity values from widely 

scattered boreholes, it is estimated that the unit-averaged 

porosity of the Park City-State Bridge zone ranges regionally 

from about 2 to 6 percent (pi. 9).

Permeability in the Park City-State Bridge zone ranges 

from small to large. Pore-scale permeability in 629 analyses of 

sandstone, dolomite, and limestone ranged from less than 0.01 

to 1.450 md (fig. 85). with median values of 0.04 md for sandstone, 0.06 md for dolomite, and 0.01 md for limestone. For 

sandstone and dolomite, a crude relation exists between porescale permeability and porosity (fig. 86). Most varieties of dolomite have median values of pore-scale permeability between 

0.01 and 0.03 md, but sandy and vuggy varieties are considerably more permeable than other varieties (table 16). Local-scale 

permeability in the Park City-State Bridge zone is significantly
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER BIB

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

Area where Park City-State Bridge zone 

is missing because of erosion or 

nondeposition

Area where Park City-State Bridge zone 

consists of shale with minor to 

subordinate carbonate, sandstone, 

gypsum/anhydrite, and phosphorite 

interbeds

Area where Park City-State Bridge zone 

consists of limestone and dolomite 

with subordinate shale, chert, and 

phosphorite interbeds and minor 

sandstone and anhydrite interbeds

Area where Park City-State Bridge zone 

consists of limestone, dolomite, and 

sandstone with minor to subordinate 

shale, chert, phosphorite, and 

gypsum/anhydrite interbeds

 200 Line of equal thickness Interval is 200 

feet

AREA EXCLUDED 

FROM STUDY

25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 83. Thickness and lithology of the Park City-State Bridge zone of the Canyonlands aquifer. 

(Modified from Geldon, in press, plate 17.)
BI14 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN. EXCLUDING SAN JUAN BASIN

O

7

6

5

O

LU

z> 4

a

LU

CC

LJ_

3

2

1 

n

-

-

-

 

-

-

| 

| |

SANDSTONE

 i

-

-

~

WjHI-l 

mK-t £1

 i i ~~

-

ou

25

20

fc

LU

13 15

0

LU

CC

u_

10

5

n

-

-

-

-

I III

LIMESTONE

-

 i 

 

-

01 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 

POROSITY, IN PERCENT

0 123456789 10 

POROSITY, IN PERCENT

160

140

120

100

Z> 80 

O

60

40

20 -

\ I

DOLOMITE

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

POROSITY, IN PERCENT

FIGURE 84. Frequency distribution of porosity in samples of sandstone, dolomite, and limestone 

from the Park City-State Bridge zone of the Canyonlands aquifer.
HYDROLOGIC PROPERTIES OF THE CANYONLANDS AQUIFER BUS

TABLE 16. Porosity and pore-scale permeability statistics for the Park City-State Bridge zones of the Canyonlands aquifer

[<, less than]

Rock type

Dolomite

Phosphatic

Limy

Anhydritic

Vuggy

Shaly

Fine-grained

Crystalline

Sandy

All

Limestone

Sandstone

Shale

Anhydrite

Minimum

0.2

.8

.7

.7

.5

.3

.2

.9

<.l

1.2

.7

4.5

.4

Porosity 

(percent)

Maximum

10.5

5.3

14.7

12.8

6.9

3.5

21.8

15.7

22.4

9.7

17.9

4.5

.4

Median

1.1

2.2

2.2

3.9

4.3

.9

1.5

10.2

2.1

3.4

7.4

4.5

.4

Number of 

observations

42

52

50

33

15

39

303

29

521

76

32

1

2

Pore-scale permeability 

(millidarcies)

Minimum Maximum

0.01 46

<.01 .50

<.01 21

.01 88

<.01 21

<.01 23.6

<.01 88

.03 36

<.01 1,450

<.01 102

<.01 187

<.01 <.01

.01 -39

Median

0.03

<.01

.03

.07

.01

.03

.03

.89

.06

.01

<01

<01

.20

Number of 

observations

42

52

50

33

15

39

303

29

521

76

32

1

2

larger than pore-scale permeability because of fracturing and 

solution. In 20 drill-stem tests and 15 conversions from porescale permeability, local-scale permeability in intervals 

composed mostly of limestone, dolomite, or sandstone ranged 

from 0.0049 to 330 md, with a median value of 2.4 md. 

Insufficient data were available to determine the range in 

permeability and median permeability values for shale, chert, 

phosphorite, or anhydrite, which comprise much of the Park 

City-State Bridge zone in northwestern Colorado and much of 

Wyoming.

HYDRAULIC CONDUCTIVITY 

AND TRANSMISSIVITY

On the basis of the previously discussed permeability data, 

hydraulic conductivity in intervals of the Park City-State 

Bridge zone composed mostly of limestone, dolomite, or sandstone was determined to range from 0.000012 to 0.80 ft/d, with 

a median value of 0.006 ft/d (fig. 87). It is estimated that unitaveraged hydraulic conductivity in the center of the Green 

River, Great Divide, Washakie, and Sand Wash Basins, where 

the Park City-State Bridge zone is deeply buried and predominantly composed of shale, is no larger than the smallest 

recorded interval values. Toward the center of uplifted areas, 

where the Park City-State Bridge zone is fractured and predominantly composed of carbonate rocks and sandstone, unitaveraged hydraulic conductivity may be as large as 1 ft/d. 

Regionally, unit-averaged hydraulic conductivity is estimated to 

range from 0.00001 to 1 ft/d, increasing from structural basins 

to uplifted areas (pi. 9).

On the basis of regional distributions of unit-averaged 

hydraulic conductivity and thickness and an empirical relation 

between transmissivity and the discharge of wells and springs 

(discussed below), the composite transmissivity of the Park CityState Bridge zone is estimated to range from 0.005 to 70 ft2/d 

(pi. 10). No estimates of composite transmissivity can be made 

for the least permeable geologic unit within this zone, the State 

Bridge Formation, but the transmissivity of the State Bridge 

Formation should be about the same as the lithologically similar 

Goose Egg Formation, which comprises the Park City-State 

Bridge zone along the eastern edge of the UCRB in Wyoming. In 

general, the composite transmissivity of the Park City-State 

Bridge zone increases from structural basins to uplifted areas.

YIELDS FROM WELLS AND SPRINGS

Yields from the Park City-State Bridge zone to wells and 

springs typically are small to moderate (pi. 10), but large yields 

are possible where composite transmissivity values exceed 

50 ft/d. In 52 determinations, artesian yields from wells and 

springs ranged from 0.39 to 2,870 gal/min, with a median value 

of 13 gal/min (fig. 88). In general, yields, in gallons per minute, 

were found to be related to composite transmissivity, in feet 

squared per day, by a factor of 10 to 1. Thus, where composite 

transmissivity ranges from 0.01 to 1 ft2/d, yields can be expected 

to range from 0.1 to 10 gal/min. Such yields typically are reported 

for drill-stem tests in structural basins or on the margins between 

basins and uplifts. Yields of 10 to 100 gal/min, which arc typical 

of the Park City Formation in the Ashley Valley oil field (pi. 10), 

characterize discharges on the flanks of uplifted areas.
B116 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

PERMEABILITY, IN MILLIDARCIES

0.001 0.1 0.32 1.0 3.2 10 32 100 320 1,0003,20010,000 

300 

250

200

>- 

o

D 150

a

100

50

0.001 

35 i 

O

30

25

20

15

10

0 

-3.0

0.001

15.0

12.5

10.0

§ 7 ' 5

5.0

2.5

"T ~T

DOLOMITE

-3.0 -1.0 -0.5 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 

LOG (BASE 10) OF PERMEABILITY, IN MILLIDARCIES

PERMEABILITY, IN MILLIDARCIES 

0.01 0.032 0.1 0.32 1.0 3.2 10 32 100 320 1,000

LIMESTONE

-2.0 -1.5 -1.0 -0.5 0 0.5 1.0 1.5 2.0 

LOG (BASE 10) OF PERMEABILITY, IN MILLIDARCIES

2.5 3.0

PERMEABILITY, IN MILLIDARCIES 

0.01 0.032 0.1 0.32 1.0 3.2 10 32 100 320 1,000

SANDSTONE

-3.0 -2.0 -1.5 -1.0 -0.5 0 0.5 1.0 1.5 2.0 2.5 3.0 

LOG (BASE 10) OF PERMEABILITY, IN MILLIDARCIES

FIGURE 85. Frequency distribution of pore-scale permeability in the Park City-State 

Bridge zone of the Canyonlands aquifer.
GROUND-WATER MOVEMENT B1L7

1,000

100

10

<

LU 

5 

EC 0.1

0.01

0.001

SANDSTONE

10,000

1,000 -

100 -

(JI

m 

<

10 

POROSITY, IN PERCENT

15 20

0.01

0.001

10 15 

POROSITY, IN PERCENT

FIGURE 86. Relation of porosity to pore-scale permeability in samples of sandstone and dolomite 

from the Park City-State Bridge zone of the Canyonlands aquifer.

The largest discharges from the Park City-State Bridge zone 

occur in uplifted areas, where the rocks are most fractured. As 

an example, springs and flowing wells near Kemmerer, Wyo., in 

the Overthrust Belt, discharge from the Phosphoria Formation at 

rates of 200 to 300 gal/min (Lines and Glass, 1975). At the eastern end of the Uinta Mountains, Taylor Ranch Warm Spring 

(SLD02-22-24ccd) discharges from the Park City Formation at 

rates varying between 112 and 449 gal/min (Maxwell and 

others, 1971, p. 21). Such discharges probably represent the 

maximum possible at the eastern end of the Uinta Mountains, 

where the Park City-State Bridge zone is extensively fractured 

and permeable but less than 100 ft thick. As the unit thickens 

toward the western end of the range, it is estimated that discharges may exceed 500 gal/min, approaching discharges 

reported in the Wind River Mountains. At the southeastern end 

of the Wind River Mountains, a flowing well (SB30-96-07b) 

discharges from the Park City Formation at a rate of 700 gal/min 

(Whitcomb and Lowry, 1968). At the northern end of the Wind 

River Mountains, Kendall Cold Spring (SB38-110-25) discharges from the Phosphoria Formation at a rate of 628 gal/min 

(Rouse, 1967, p. 3-4). As noted previously, Kendall Warm 

Spring, with a discharge of about 2,900 gal/min, also discharges

from the Phosphoria Formation in the Wind River Mountains. 

However, as shown in figure 88, the discharge from this spring 

clearly is an outlier for the Park City-State Bridge zone. For 

reasons explained previously, Kendall Warm Spring probably is 

an outlet for water rising from the Tensleep Sandstone along the 

Wind River fault.

GROUND-WATER MOVEMENT

Though aquifers and confining units can be distinguished by 

hydrologic properties, it is apparent from the preceding discussion that all hydrogeologic units composed of Paleozoic rocks in 

the UCRB store and transmit water. Ground water moves not only 

from recharge areas to discharge areas within aquifers but from 

aquifers to aquifers through confining units throughout the 

UCRB. Primarily, ground water flows from structurally and topographically raised areas to structural basins and the incised 

canyons of the Colorado and Green Rivers and major tributaries. 

Movement occurs along regional, intermediate (subregional), and 

local flow paths (see Freeze and Cherry, 1979, p. 192-199, for a 

discussion of flow paths).
B118 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

HYDRAULIC CONDUCTIVITY, IN FEET PER DAY

0.00001 0.000032 0.0001 0.00032 0.001 0.0032 0.01 0.032 0.1 

10

9 -

0.32

Shale and dolomite 

Sandstone

Dolomite, limestone, and 

sandstone

-5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 

LOG (BASE 10) OF HYDRAULIC CONDUCTIVITY, IN FEET PER DAY

-0.5

FIGURE 87. Frequency distribution of hydraulic conductivity in the Park City-State 

Bridge zone of the Canyonlands aquifer.

Within the Four Corners aquifer system, aquifers and 

confining units are connected hydraulically by fractures, 

solution channels, and permeable beds, and head differences 

from the top to the bottom of the aquifer system generally are 

less than 500 ft. The Redwall-Leadville zone of the Madison 

aquifer transmits most of the water in the Four Corners aquifer 

system, and heads within this hydrogeologic unit define the 

potentiometric surface for the aquifer system (pi. 11). 

Subregional aquifers and confining units in the Four Corners 

aquifer system transmit water as lithologic, structural, topographic, and weathering conditions permit.

The Four Corners confining unit separates the Four Corners 

aquifer system from the Canyonlands aquifer, except in areas of 

structural disturbance or where the confining unit is missing 

because of erosion or nondeposition. Because of the effectiveness

of the Four Corners confining unit in retarding vertical groundwater movement, head differences between the Canyonlands 

aquifer and Four Corners aquifer system in many areas exceed 

1,000 ft (fig. 89).

In the Canyonlands aquifer, the Weber-De Chelly zone 

transmits most of the water. Where the Weber-De Chelly zone 

pinches out and becomes unsaturated in the eastern part of the 

UCRB, the Cutler-Maroon zone becomes the dominant watertransmitting zone within the Canyonlands aquifer. The potentiometric surface of the Canyonlands aquifer (pi. 11) is a 

composite of heads in the Weber-De Chelly and Cutler-Maroon 

zones where each zone is dominant. In the Cutler-Maroon and 

Park City-State Bridge zones, water is transmitted as lithologic, 

structural, topographic, or weathering conditions permit. 

Contiguous permeable intervals in some areas hydraulically 

connect the zones within the Canyonlands aquifer; in other
GROUND-WATER MOVEMENT B119

areas, thick intervals of negligibly permeable rocks isolate 

permeable intervals within zones or sever hydraulic connection 

between zones within the aquifer.

Vertical head gradients between the Canyonlands aquifer and 

the Four Corners aquifer system indicate that water can be 

recharged to the Four Corners aquifer system by downward movement from the Canyonlands aquifer even in areas where the Four 

Corners aquifer system is deeply buried. In other areas, vertical 

head gradients favor upward movement of water from the Four 

Corners aquifer system to the Canyonlands aquifer. In figure 89, 

for example, vertical head gradients between the Canyonlands 

aquifer and Four Corners aquifer system indicate a potential for 

downward ground-water movement in the Monument Upwarp 

and upward ground-water movement in the Blanding Basin.

Patterns of ground-water movement within the Paleozoic 

rocks are complicated further by lithologic variability within 

underlying Precambrian rocks and overlying Mesozoic rocks. As 

a result of this variability, distinctions in some areas between 

hydrogeologic units composed of Paleozoic rocks and those 

composed of Precambrian or Mesozoic rocks are somewhat arbitrary. For example, in the Uinta Mountains and vicinity, in the 

Lees Ferry area, and in a few other areas throughout the UCRB

where the uppermost Precambrian rocks are sedimentary (fig. 15), 

Precambrian sandstone, conglomerate, and limestone probably 

transmit water together with the Four Corners aquifer system. In 

areas where the lowermost Mesozoic rocks consist largely of 

sandstone, conglomerate, or limestone (fig. 17), the Mesozoic 

rocks commonly are connected hydraulically to the Canyonlands 

aquifer. For example, in the Defiance Plateau area, many wells 

draw water from the De Chelly Sandstone of Permian age and the 

overlying Shinarump Conglomerate Member of the Chinle 

Formation of Triassic age (Davis and others, 1963). In some areas 

where the uppermost or lowermost Paleozoic formations consist 

mostly of shale or quartzite, the Paleozoic rocks have more in 

common with the underlying basal and overlying ChinleMoenkopi confining units than with the hydrogeologic units to 

which the Paleozoic rocks have been assigned. For example, 

where the State Bridge Formation, Goose Egg Formation, or shaly 

members of the Park City and Phosphoria Formations comprise 

the uppermost Paleozoic rocks, the uppermost Paleozoic rocks 

and lowermost Triassic rocks generally function together to 

impede ground-water movement.

0.10 0.16 0.25 0.40 0.63 1.0

10

1.6 2.5 4.0

YIELD, IN GALLONS PER MINUTE 

n i i i i i i i i i r~ 6.3 10 16 25 40 63 100 160 250 400 6301,0001.6002,5004,0006,30010,000

>u

a

-1.0 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 

LOG (BASE 10) OF YIELD, IN GALLONS PER MINUTE

FIGURE 88. Frequency distribution ot yields from the Park City-State Bridge zone of the Canyonlands aquifer.
B120 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COEORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

A

FEET 

9,000 -,

8,000 - 

7,000 -

A'

NGVD 

of 1929

-1,000

MONUMENT UPWARP 

Grand Gulch Plateau

San 

Juan 

River

10 MILES

0510 KILOMETERS 

VERTICAL EXAGGERATION APPROXIMATELY X10

EXPLANATION 

Geologic and hydrologic units Four Corners confining unit

Jurassic rocks 

Triassic rocks

Canyonlands aquifer

Cutler Group (of Baars, 1962) 

and Rico Formation

Upper member of Hermosa 

Formation

| IPhp I Paradox Member of Hermosa 

Formation

IPhlm Lower Member of Hermosa

Formation and Molas Formation

Four Corners aquifer system 

Ml Leadville Limestone

D Devonian rocks

1

Contact between geologic units Dashed and queried where underlying geology 

is unknown

Potentiometric surface for the Canyonlands aquifer From plate 2 

Potentiometric surface for the Four Corners aquifer system From plate 2 

Fault Arrows indicate relative direction of movement 

Borehole

FIGURE 89. Geologic section showing head differences between the Canyonlands aquifer and the Madison aquifer of the Four Corners 

aquifer system in southeastern Utah. (Modified from Thackston and others, 1981, p. 210. Location of section shown in fig. 14.)

RECHARGE TO THE PALEOZOIC ROCKS

Recharge to the Paleozoic rocks occurs from precipitation, 

either directly or by stream-flow losses, and from interbasin 

flow. In general, recharge areas are characterized by downward 

ground-water movement, losing streams, unsaturated rock, 

water-table conditions, and fresh ground water. In contrast,

discharge areas are characterized by predominantly upward 

ground-water movement, gaining streams, springs, flowing 

artesian wells, and brackish to briny ground water.

The largest potential for recharge exists where head differences between the Canyonlands aquifer and the Four Corners 

aquifer system are the most positive. Head differences between 

the Canyonlands aquifer and the Redwall-Leadville zone of the
GROUND-WATER MOVEMENT B121

Madison aquifer, as indicated on plate 12, range from less than 

-3,500 to more than +3,500 ft. A large potential for recharge 

can be inferred where head differences are more positive than 

+3,500 ft. Among areas where such large head differences occur 

are the Wind River, Uinta. Elk, Abajo, and Elkhead Mountains; 

La Sal Mountains; the Sierra Madre; the Park and Sawatch 

Ranges; the Uncompahgre and Kaibito Plateaus; the Cattle 

Creek Plateau (southern) section of the White River Plateau; the 

Wasatch and Fish Lake Plateaus (northern) section of the High 

Plateaus region; the Tavaputs Plateau, Roan Plateau, and Grand 

Mesa sections of the Uinta and Piceance Basins; the Sweetwater 

Arch; an arcuate area extending from the San Juan Mountains 

through the Sage Plain and Elk Ridge to the Grand Gulch 

Plateau; and several grabens in the Paradox Basin, including the 

Verdure, Lisbon Valley, and Big Gypsum Creek grabens. 

According to Metzger (1961) and Cooley and others (1969), 

predominantly downward ground-water movement also 

prevails in the Kaibab Plateau area.

Recharge and discharge areas and ground-water flow paths 

can be discerned from hydrochemical data as well as potentiometric heads. Areas in which the Redwall-Leadville zone of the 

Madison aquifer and the Weber-De Chelly zone of the 

Canyonlands aquifer contain freshwater (dissolved-solids concentrations of 1,000 mg/L or less) can be regarded as recharge areas 

for the Paleozoic rocks. Areas in which the Redwall-Leadville and 

Weber-De Chelly zones contain brackish to saline or briny water 

(dissolved-solids concentrations of 1,000 to as much as 

300,000 mg/L) can be regarded as discharge areas for the 

Paleozoic rocks. The distribution of dissolved solids in water from 

the Redwall-Leadville and Weber-De Chelly zones is shown in 

figures 90 and 91. Together with topography, the distribution of 

average annual precipitation, the locations of losing and gaining 

reaches of streams, and the locations of springs, hydrochemical 

and potentiometric head data indicate that numerous recharge 

areas for the Paleozoic rocks exist within and peripheral to the 

UCRB (fig. 92).

PRECIPITATION

Precipitation is the major source of recharge to the 

Paleozoic rocks. Rain and snow falling on mountaintops, 

plateaus, ridges, mesas, and buttes infiltrate outcropping 

Paleozoic rocks or slowly percolate down through overlying 

volcanic and sedimentary rocks. Snowcover and storms of 

several days' duration prolong recharge. In contrast, summer 

thunderstorms provide little recharge because most of the rain 

from these storms immediately evaporates or runs off into 

stream channels. Recharge from precipitation is possible in 

areas receiving as little as 10 inches of average annual precipitation. For example, the Rawlins Uplift, with 11 inches of 

average annual precipitation, the San Rafael Swell, with 8 to 

12 inches of average annual precipitation, and the Rainbow 

Plateau, with about 10 to 12 inches of average annual precipitation, all are reported to be recharge areas for Paleozoic and 

Mesozoic rocks (Berry, 1960; Cooley and others, 1969; Hood

and Patterson, 1984). In most areas, including structural basins, 

altitudes above 5,900 ft generally receive at least 10 inches of 

precipitation in most years (fig. 11). On the basis of climatic 

studies in the region (previously cited in this report), it is estimated that evapotranspiration consumes between 45 and 

90 percent of precipitation at altitudes between 6,000 and 

9,000 ft, less precipitation at higher altitudes, and nearly all 

precipitation at lower altitudes.

Because of the lack of data, it is impossible to accurately 

determine the average annual evapotranspiration and, hence, 

the average annual recharge from precipitation to groundwater systems in the UCRB, excluding the San Juan Basin. 

However, for the entire UCRB. lorns and others (1965, p. 10) 

calculated that the average annual precipitation was about 

93,000,000 acre-ft and the average annual evaporation from 

water surfaces was 575,000 acre-ft (0.6 percent of the average 

annual precipitation). Subtraction of the water-surface evaporation and known stream outflows from the UCRB from the 

average annual precipitation would result in an unrealistically 

large estimate of recharge.

In a study of the northern Uinta Basin, encompassing an 

altitude range of 4,650 to 13,000 ft (similar to the entire UCRB) 

and an area of 5,200 mi2, Hood and Fields (1978, p. 20) estimated recharge as a function of topography and precipitation 

and concluded that only about 10 percent of the average annual 

precipitation was available for recharge to aquifers in Paleozoic, 

Mesozoic, and Tertiary rocks in the area (table 17).

The results of a ground-water modeling study in southeastern Utah by Dunbar and Thackston (1985) also are enlightening. This study area was approximately 6,140 mi and 

encompassed an altitude range of 3,500 to 12,700 ft. Direct 

surface recharge to the uppermost layer of Paleozoic rocks was 

estimated as a function of precipitation rates, topography, and 

the extent of outcrops of the Triassic Moenkopi and Chinle 

Formations (which in the area of the study comprise the lowermost confining unit above the Paleozoic rocks the ChinleMoenkopi confining unit). Through calibration, empirical relations developed by Eakin and others (1951) and Fiero (1968) 

applied to the local topographic and precipitation data were 

modified, resulting in estimates of recharge ranging from 0.05 

to 0.55 in/yr in areas where the Paleozoic rocks are not covered 

by the Chinle-Moenkopi confining unit. The total recharge to 

Paleozoic rocks in the area was estimated to be 8.09 IV/s 

(5,900 acre-ft/yr), which would indicate that 99.8 percent of the 

ambient average annual precipitation (3,100,000 acre-ft/yr, 

according to Dunbar and Thackston, 1985, fig. 5.1) does not 

reach the Paleozoic rocks in the area of the study.

Given the different methods of estimating recharge from 

precipitation in past studies within the UCRB, any figure 

presented in this report must be considered tentative. If one uses 

the simplified method of Hood and Fields (1978), then, as shown 

in table 18, the total precipitation influx to the UCRB, excluding 

the San Juan Basin, is estimated to be 83,000,000 acre-ft/yr and 

the recharge available to ground-water systems (not necessarily
B122 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

110=

42

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

No Data

PlrwdHeVV'.'-VV O

I \. /. . > Lande

EXPLANATION

Dissolved-solids concentration 

in milligrams per liter

Less than 1,000 

1,000 to 10,000 

10,000 to 100,000 

More than 100.000

Area where Redwall-Leadville 

zone is missing because of 

erosion or nondeposition

 - Line of equal dissolved-solids 

concentration Dashed 

where approximately located

AREA EXCLUDED 

FROM STUDY

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 90. Concentration of dissolved solids in water from the Redwall-Leadville zone of the Madison aquifer. (Modified from 

Lindner-Lunsford and others, 1985; Briant Kimball, U.S. Geological Survey, written commun., 1990.)
GROUND-WATER MOVEMENT B123

42'

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

EXPLANATION

Dissolved solids-concentration 

in milligrams per liter

Less than 1.000 

1,000 to 3,000 

3,000 to 10,000 

10,000 to 35,000 

More than 35,000

'_ ';] Area where Weber-De Chelly 

zone is missing because of 

erosion or nondeposition

 - Line of equal dissolved-solids 

concentration Dashed 

where approximately located

 AREA EXCLUDED 

FROM STUDY

25

I

50 

I

75

0 25 50 75 100 KILOMETERS

FIGURE 91. Concentration of dissolved solids in water from the Wcber-De Chelly zone of the Canyonlands aquifer.

(Modified from Lindner-Lunsford and others, 1985.)
B124 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

GROS 

VENTRE

HOBACK RANGE 

BASIN

TUNP 

RANGE

BOUNDARY OF 

UPPER COLORADO 

RIVER BASIN

EXPLANATION

Recharge area for Paleozoic rocks 

Discharge area for Paleozoic rocks

Reach of stream crossing outcrops of 

Paleozoic rocks with measured or 

estimated base-flow gain

Reach of stream crossing outcrops of 

Paleozoic rocks with measured or 

estimated base-flow loss

Flowing well completed in Paleozoic 

rocks

Spring issuing from Paleozoic rocks 

with a discharge of 50 gallons per 

minute or more

Spring issuing from Paleozoic rocks 

with a discharge of less than 50 

gallons per minute

 AREA EXCLUDED 

FROM STUDY

75 100 MILES

0 25 50 75 100 KILOMETERS

FIGURE 92. Recharge and discharge areas for the Paleozoic rocks in the Upper Colorado River Basin.
GROUND-WATER MOVEMENT B125

TABLE 17. Estimated average annual volumes of precipitation and ground-water recharge, 1941-70, in the northern 

Uinta Basin and Uinta Mountains (Hood and Fields, 1978)

[less than; < , equal to or less than]

Precipitation zone 

(inches)

<8

8-10

10-12

12-14

14-16

16-18

18-20

20-22

22-24

24-26

26-30

30-34

34-38

38<42 

Totals

(rounded)

Acres 

(acres)

295,800

507,200

293,000

258.000

241,500

241,600

230,800

221,300

165,900

132,100

243,700

266,000

167,300

12,500

3,277,000

Estimated average annual precipitation

Feet

0.58

.75

.92

1.08

1.25

1.41

1.57

1.73

1.89

2.06

2.31

2.64

2.96

3.25

Acre-feet

171.600

380,400

269,600

278,600

301,900

340.700

362,400

382,800

313,600

272,100

562,900

702,200

495,200

40,600

4,870,000

Estimated average annual 

ground-water recharge

Percentage of 

precipitation

0

0

1

2

2

5

5

10

10

15

15

20

25

25

Acre-feet

0

0

2,700

5,600

6,000

17,000

18,100

38,300

31,400

40,800

84,400

140,400

123,800

10,200

500,000

TABLE 18. Estimated average annual volumes of precipitation and ground-water recharge, 1931-80, in the Upper Colorado River Basin, 

excluding the San Juan Basin (based on planimeter measurements of contoured areas in fig. 10)

[<. less than; >, greater than]

Precipitation zone 

(inches)

<6

6-10

10-20

20-30

30-40

>40 

Totals

(rounded)

Area 

(acres)

2,209,939

21,344,557

29,765,971

7.912,128

3,919,686

745,741

66,000,000

Estimated average annual precipitation

Feet

0.42

.67

1.25

2.08

2.92

3.75

Acre-feet

928,174

14,300,853

37,207,464

16,457,226

11,445,483

2,796,529

83,000,000

Estimated average annual 

ground- water recharge

Percentage of 

precipitation

0

0

3

13

23

25

Acre-feet

0

0

1,116,224

2,139,439

2,632,460

699,132

6,600,000
B126 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

to aquifers composed of Paleozoic rocks) is 6,600,000 acre-ft/yr 

(1.2 in/yr). If Dunbar and Thackston (1985) are correct, most of 

this potential recharge is captured by aquifers in Mesozoic and 

Tertiary rocks, and little of this water moves downward into the 

Paleozoic rocks.

INTERBASIN FLOW

As seen on plate 11, surface-water and ground-water divides 

peripheral to the UCRB coincide in all but a few areas. 

However, potentiometric contours indicate that ground water 

flows into the UCRB from the Sierra Madre, the south flank of 

the Sweetwater Arch, the Hoback Basin, the Overthrust Belt, 

the east flank of the Wasatch Range and northwestern corner of 

the Uinta Basin, the High Plateaus region, and the Kaibab 

Plateau. In each of these areas, Quaternary surface-water 

divides have been superimposed upon preexisting structures. 

The Paleozoic rocks of the UCRB extend beneath these surfacewater divides and crop out in the areas providing recharge to the 

UCRB. Distances to these recharge areas from the boundary of 

the UCRB range from less than 1 to 21 mi.

The volume of interbasin flow providing recharge to 

Paleozoic rocks in the UCRB can be estimated from Darcy's 

Law (Freeze and Cherry, 1979, p. 16) using topographic maps, 

geologic maps (figs. 14,41,65, and 74), and hydraulic gradients 

and transmissivity values for the Madison and Canyonlands 

aquifers (from pis. 3, 6, 8, and 11). This approach assumes that 

flow into the UCRB from hydrogeologic units other than the 

Redwall-Leadville zone of the Madison aquifer and the CutlerMaroon and Weber-De Chelly zones of the Canyonlands 

aquifer is inconsequential. As shown in table 19, the total 

volume of interbasin flow contributing recharge to Paleozoic 

rocks in the UCRB is estimated to be about 1,000 acre-ft/yr. The 

recharge from interbasin flow is less than 1 percent of the estimated recharge from precipitation available to aquifers in 

Pale'nsozoic, Mesozoic, and Tertiary rocks in the UCRB.

STREAMFLOW

Not all of the precipitation that becomes recharge directly 

infiltrates aquifers in the UCRB. Some of this precipitation runs 

off into streams and then infiltrates bedrock beneath or along 

the channels. Ephemeral streams crossing outcropping or shallowly buried Paleozoic rocks are believed to provide recharge in 

the Rawlins Uplift (Berry, 1960, p. 31), Sierra Madre (Welder 

and McGreevy, 1966), San Rafael Swell (Hood and Patterson, 

1984, p. 30), Dirty Devil River Basin (Hood and Danielson,

1981. p. 32), northwestern Paradox Basin (Rush and others,

1982. p. 29), Navajo and Hopi Indian Reservations (Cooley and 

others, 1969, p. 40), and northern Uinta Basin (Hood and Fields, 

1978, p. 32-33). In the latter area, recharge from streams is estimated to be only 4 percent of the average annual recharge to the 

aquifers that are present.

Streamflow losses from perennial streams to Paleozoic 

rocks can be substantiated in only a few areas. Where the 

Dolores River crosses the Big Gypsum graben, the base-flow

discharge of the river decreases from 38 to 31 ft3/s (Warner and 

others, 1985). Most of the lost streamflow is believed to seep 

into Mesozoic rocks along the channel, but some may be infiltrating outcropping carbonate, clastic, and evaporitic rocks of 

the Pennsylvanian Hermosa Formation. In the headwater 

reaches of Ashley Creek, Brush Creek, and Little Brush Creek, 

all or part of the streamflow in individual creeks disappears into 

Mississippian carbonate rocks through in-channel sinkholes 

and caves (Maxwell and others, 1971). Most of the lost streamflow emerges shortly downstream as springs issuing from 

Pennsylvanian, Permian, and Triassic formations. Some, 

however, remains as ground water in the Paleozoic rocks (Feltis, 

1966, p. 12).

FLOW PATHS

Because of highly variable topography within and peripheral to the UCRB, water in the Paleozoic rocks of the UCRB is 

forced to flow toward local and subregional outlets, rather than 

toward a single, regional discharge area (pi. 11). Although some 

ground water flows vertically through the Four Corners 

confining unit, the generally small permeability of this 

confining unit inhibits interchange of water between the underlying Four Corners aquifer system and the overlying 

Canyonlands aquifer. Ground-water movement in the Paleozoic 

rocks ultimately is directed mainly toward four areas the 

eastern Great Divide Basin (between the Rawlins Uplift and 

Sierra Madre), the confluence of the Yampa and Green Rivers, 

the San Juan Basin, and the confluence of the Colorado and 

Little Colorado Rivers. The fourth area is in the Lower 

Colorado River Basin, just south of the politically defined 

boundaries of the UCRB.

CIRCULATION IN THE FOUR CORNERS 

AQUIFER SYSTEM

Ground-water circulation in the Four Corners aquifer 

system is constrained by the Continental Divide from the 

San Juan Mountains to the Sierra Madre and by potentiometric 

divides elsewhere. In this report, these potentiometric divides 

are called the Wind River-Northern Great Plains divide from 

the Sierra Madre through the Rawlins Uplift and Sweetwater 

Arch to the Wind River Mountains; the Upper Colorado River 

Basin-Basin and Range divide from the Gros Ventre Range and 

Overthrust Belt through the Uinta Mountains and Wasatch 

Range to the High Plateaus and Kaibab Plateau; the Black Mesa 

divide from the Kaibito Plateau through Black Mesa to the 

Defiance Plateau; and the San Juan-Chuska divide from the 

Chuska Mountains to the San Juan Mountains. Within the 

UCRB, subregional ground-water flow paths in the Four 

Corners aquifer system are influenced by six potentiometric 

divides the Uinta-Park, Tavaputs, Grand Mesa-White River, 

Eagle, Circle Cliffs, and Monument divides (pi. 11).
GROUND-WATER MOVEMENT B127

TABLE 19. Estimated annual interbasin flow contributing recharge to Paleozoic rocks in the Upper Colorado River Basin 

[A question mark indicates the value is a rough estimate based on topographic and geologic maps and extrapolation of data from other areas]

Aquifer zones

Weber-De Chelly zone

Cutler-Maroon zone

Redwall-Leadville zone

Weber-De Chelly zone

Cutler-Maroon zone

Redwall-Leadville zone

Weber-De Chelly zone

Cutler-Maroon zone

Redwall-Leadville zone

Weber-De Chelly zone

Cutler-Maroon zone

Redwall-Leadville zone

Weber-De Chelly zone

Cutler-Maroon zone

Redwall-Leadville zone

Weber-De Chelly zone

Cutler-Maroon zone

Redwall-Leadville zone

Weber-De Chelly zone

Cutler-Maroon zone

Redwall-Leadville zone

Total

Average transmissivity . , , .. Flow-path width 

,- , Average hydraulic gradient .. (feet squared per day) fc J fc (feet)

5.1

1.5

.36(7)

.39(7)

1.7

.76(7)

.81(7)

8.5

1.4 (?)

1.2 (?)

5.6

1-2 (?)

.64

.90 (?)

1.4(?)

1.4(?)

Sierra Madre

0.011

Missing

Ground-water and surface-water divides coincide

Sweetwater Arch

.052

.052

.019

Hoback Basin

.0086

.0086

.025

Overthrust Belt

.043

.043

.0094

Uinta Basin

.014

Missing

.018

High Plateaus

.026

.026

.029

Kaibab Plateau

Missing

.047

Ground-water and surface-water divides coincide

105,600

279,840

279,840

369,600

121,440

121,440

168,960

42,240

42,240

15,840

142,560

279,840

667,920

667,920

401,280

174,240

Annual interbasin flow 

contributing recharge 

(acre-feet per year)

50

0

0

183

44

23

15

6.6

29

129

21

1.5

94

0

50

94

131

138

0

96

0

1,120

North of the Uinta-Park divide, water in the Four Corners 

aquifer system primarily moves from peripheral and internal 

highlands toward the eastern edge of the Great Divide Basin, 

where it flows through a gap between the Rawlins Uplift and 

Sierra Madre into the Hanna Basin. Large springs, such as 

Hogsback Spring (SB26-114-Olbac) and Sheep Creek 

Spring (SLA02-19-16bcb) in the Overthrust Belt, oil and gas 

field pumpage in the Overthrust Belt and Rock Springs Uplift 

(table 20), and a few water wells in the Rawlins area deplete 

some of the water in circulation. In the interior of the greater 

Green River and Sand Wash Basins, water under the influence 

of strongly upward hydraulic gradients seeps up into 

Pennsylvanian and Permian rocks.

Between the Uinta-Park and Tavaputs divides, circulation in 

the Four Corners aquifer system is directed primarily toward the 

confluence of the Yampa and Green Rivers on the southeast 

flank of the Uinta Mountains (Geldon, 1986). However, some of

the water in circulation issues as springs in recharge areas, and 

some flow is directed toward the Glenwood Springs area and 

Eagle Basin by the Grand Mesa-White River and Eagle divides.

Considerable volumes of water discharge from the aquifer 

system not far from the recharge areas between the Uinta-Park and 

Tavaputs divides. For example, Teller and Welder (1983, p. 12) 

indicate that springs and seeps entering a 4-mi reach of Rifle 

Creek where it is incised into the White River Plateau upstream 

from the Rifle Falls Fish Hatchery have a combined discharge of 

28 ft3/s. Bowles Fish Hatchery Spring (SC08-83-09), in the 

Sawatch Range, has a discharge of 1,123 gal/min (lorns and 

others, 1964).

According to URS Corp. (1983), the combined discharge 

of seeps and springs into Glenwood Canyon between Dotsero 

and Glenwood Springs is 30.2 ft3/s; the combined flow of hot 

springs and seeps at Glenwood Springs is about 4,300 gal/min 

(Geldon, 1989c). The topography and geology of the
B128 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

TABLE 20. December 1986 water production from oil and gas fields where the principal resen'oir is in Paleozoic rocks of the

Upper Colorado River Basin

[Location of most oil and gas fields shown on pi. 11. Source of data is Petroleum Information Corp., written commun., 1987]

Field

Lost Soldier 

Wertz-Mahoney

Brady

O'Brien Springs

Happy Springs

Butcher Knife 

Springs

Moxa

Rangely

Ashley Valley

Elk Springs

Moffat

Danforth Hills

Upper Valley

Boundary Butte

Barker Dome

Perron 

Subtotal

Greater Aneth

Marble WashTowaoc

Long Canyon

Bug

Tohonadla

Patterson Canyon

Turner BluffCowboy

Papoose Canyon

Teec Nos Pos 

Subtotal

Table Rock

Lake RidgeFogarty CreekDry Piney

Greater Lisbon

Salt Wash

Dry Mesa

McElmo 

Subtotal 

Total

State

Wyoming

Wyoming

Wyoming

Wyoming

Wyoming

Wyoming

Colorado

Utah

Colorado

Colorado

Colorado

Utah

Utah, 

Arizona

Colorado

Utah

Utah,

Colorado

Colorado

Utah

Utah

Utah

Utah

Utah

Colorado

Arizona

Wyoming

Wyoming

Utah

Utah

Arizona

Colorado

Type

Oil, gas

Oil, gas

Oil

Oil

Gas

Gas

Oil

Oil

Oil

Oil

Oil

Oil

Oil, gas

Oil

Oil

Oil

Oil

Oil

Oil

Oil

Oil

Oil

Oil

Gas

Gas

Gas

Oil, Gas

Oil

Oil

Oil

Principal Paleozoic ,_ , Other reservoirs reservoirs(s)

Canyonlands aquifer

Tensleep Sandstone, Madison Limestone, Flathead 

Amsden Formation Sandstone, Triassic, Jurassic, 

and Cretaceous rocks

Weber Sandstone Jurassic and Cretaceous rocks

Tensleep Sandstone Jurassic and Cretaceous rocks

Park City Formation Cretaceous rocks

Morgan Formation Cretaceous rocks

Morgan Formation Cretaceous rocks

Weber Sandstone Triassic, Jurassic, and Cretaceous rocks

Weber Sandstone, Jurassic and Cretaceous rocks 

Park City Formation

Weber Sandstone

Weber Sandstone and Triassic, Jurassic, and Cretaceous rocks

Pennsylvanian rocks

Weber Sandstone Triassic, Jurassic, and Cretaceous rocks

Permian rocks

Cutler and Hermosa Formations

Hermosa Formation

Permian rocks

Four Corners confining unit

Paradox Member of Hermosa Formation

Paradox Member of Hermosa Formation

Paradox Member of Hermosa Formation

Paradox Member of Hermosa Formation

Paradox Member of Hermosa Formation

Paradox Member of Hermosa Formation

Paradox Member of Hermosa Formation

Paradox Member of Hermosa Formation

Paradox Member of Hermosa Formation

Four Corners aquifer system

Madison Limestone Weber Sandstone, Jurassic, 

Cretaceous, and Tertiary rocks

Madison Limestone, Jurassic and Cretaceous rocks 

Bighorn Dolomite

Leadville Limestone, Permian rocks

Devonian rocks

Redwall Limestone

Leadville Limestone

Leadville Limestone Cutler Formation

Water production

Gallons 

per minute

8,620

311

109

6.9

.23

.058

15,046

1,086

17

3.5

.12

578

65

1.6

.12

25,845

2,243

1.2

.45

.28

.96

4.8

3.2

.56

.44

2,255

45

121

164

.56

3.7

18

352.3

28,452

Cubic feet 

per second

19.2

.69

.24

.015

.00051

.00013

33.5

2.4

.038

.0078

.00027

1.3

.15

.0036

.00027

57.6

5.0

.0026

.0019

.062

.0021

.011

.0071

.0012

.00098

5.09

0.10

.27

.37

.0012

.0082

.040

0.79

63.5
GROUND-WATER MOVEMENT B129

Glenwood Springs area and the chemistry of water 

discharging at Glenwood Springs indicate that most of the 

water reaching Glenwood Springs is from areas to the south 

(pi. 11 and fig. 93). The water discharging at Glenwood 

Springs is a sodium chloride type with an average dissolvedsolids concentration of about 20,000 mg/L (Geldon, 1989c). 

Plots of log Q/K (defined in fig. 94) against temperature, 

drawn from output of the speciation program SOLVEQ 

(Spychcr and Rccd, 1989a) for minerals in equilibrium with 

water discharging from the Leadville Limestone at Glenwood 

Springs, indicate a water-rock equilibration temperature of 

about 90°C (fig. 94). Assuming this equilibration temperature 

and recharge similar in composition to the least evolved water 

from the Maroon Formation in the Crystal River-Cattle Creek 

area (Brogdcn and Giles, 1976a), the reaction-flow-path 

model CHILLER (Spycher and Reed, 1989b) successfully 

simulated the chemistry of the water discharging at Glenwood 

Springs (fig. 95) by the following flow path:

a. Meteoric water with a temperature of about 5°C infiltrates 

the Maroon Formation on the Cattle Creek Plateau or in 

the Elk Mountains.

b. Descending through about 9,000 ft of the Maroon 

Formation, Gothic Formation, Eagle Valley Evaporite, 

and Belden Formation, the water is heated to about 90°C 

and reacts sequentially with aluminosilicate minerals, 

gypsum, halite, and illite.

c. In the Leadville Limestone and Dyer Dolomite, the water 

travels toward Glenwood Springs, equilibrating with carbonate minerals along the flow path.

d. At Glenwood Springs, the water rises rapidly along faults, 

cools to 49°C, and in the process, precipitates micaceous 

minerals, kaolinite, calcite, hematite, and quartz.

The Continental Divide and the Eagle ground-water divide 

direct flow in the Four Corners aquifer system toward the center 

of the Eagle Basin where tremendous artesian pressures have

6,000 -

4,000

10 MILES

_|

10 KILOMETERS

VERTICAL EXAGGERATION X8.6 

NATIONAL GEODETIC VERTICAL DATUM OF 1929

EXPLANATION

Geologic units

Tertiary basalt

Mesozoic rocks and State Bridge 

Formation

Weber Sandstone. Maroon 

Formation, and Minturn 

Formation

Eagle Valley Evaporite, Belden 

Formation, and Molas 

Formation

Fault Arrows indicate relative direction of movement 

Direction of ground-water flow

Leadville I .imestone and Dyer 

Dolomite

Parting Formation, Manitou 

Dolomite, Dotsero Formation, 

and Sawatch Quartzite

Precambrian igneous and 

metamorphic rocks

FIGURE 93. Generalized geologic section across the White River Plateau showing ground-water circulation 

in the Paleozoic rocks (location of section is shown on pi. 11).
B130 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN. EXCLUDING SAN JUAN BASIN

-10

-15

-20

Quartz

Albite

Microcline

Muscovite

Phlogopite

Kaolinite

Hematite

Anhydrite

Serpentine

Tremolite

Equilibration temperature 

indicated by the intersection 

of trend lines for quartz, 

albite, microcline, phlogopite, 

kaolinite, hematite, and 

anhydrite with log Q/K = 0 line 

at about 90°C

25 50 75 100 125 150 175 

TEMPERATURE, IN DEGREES CELSIUS

200 225 250

FIGURE 94. Plot of log (- rrr: . ^ ) against temperature for water from the Leadville Limestone Equilibrium constant

discharging from the Redstone 21-9 well at Glenwood Springs, Colorado.

built up. One well in this area (SC02-84-02bc), after penetrating the Leadville Limestone, created a geyser 300 ft high 

and produced a discharge that decreased with time from 9.500 

to 3,200 gal/min (Hampton, 1974; Colorado Department of 

Natural Resources State Engineers Office, written commun., 

1983). However, in 1988, this well and others in the area with 

similarly large discharges were not known to be in use.

Between the Tavaputs and Uinta-Park divides and west of 

the Grand Mesa-White River divide, several springs on the 

south flank of the Uinta Mountains, such as Big Spring 

(UB01-08-l7cbb), Indian Big Spring (UB02-02-05dbb), and 

Pole Creek Spring (UB03-02-34d), discharge large volumes 

of water from the Four Corners aquifer system not far from 

sources of recharge. Pole Creek Spring, for example, has a 

discharge that varies seasonally from 2 to 25 ft3/s (Maxwell 

and others, 1971, p. 15). However, considerable volumes of

ground water do not discharge locally but flow to the far end 

of the subregional flow path and emerge at Split Mountain 

Warm Spring (SLD 04-24-16cdd), which has a discharge of 

2.700 gal/min.

South of the Tavaputs divide and north of the Circle Cliffs and 

Monument divides, water in the Four Corners aquifer system 

moves west from the San Juan Mountains, south and east from 

the San Rafael Swell-Capitol Reef-High Plateaus area, and 

northwest from the Elk Ridge-Abajo Mountains area (Hanshaw 

and Hill. 1969. p. 271-272; INTERA Environmental 

Consultants, Inc., 1984. p. 59). Because of faulting and topography, several springs with an average combined discharge of 

672 gal/min issue from the Leadville Limestone at Ouray, Colo. 

(David Vince, City of Ouray, written commun., 1988). The 

discharges of some of these springs are relatively constant, 

whereas others vary substantially throughout the year (fig. 96) in
GROUND-WATER MOVEMENT B131

response to melting of the snowpack in the San Juan Mountains. 

Geothermal wells in use by the City of Ouray in 1988 flowed at a 

combined average rate of 388 gal/min. (Other geothermal wells 

have been completed at Ouray but were not in use in 1988.) In the 

western Paradox Basin and vicinity, ground water moves into 

closed depressions in the potentiometric surface, resulting in 

stagnation. According to Thackston and others (1981, p. 219), 

this stagnant water is trapped in density-driven convection cells. 

Some of the water in the Paradox Basin is pumped from oil and 

gas fields, such as the greater Lisbon oil field (table 20).

Between the Monument, Black Mesa, and San Juan-Chuska 

divides, all water in the Four Coiners aquifer system apparently 

moves toward the vicinity of the San Juan River and the greater 

Aneth oil and gas fields (pi. 11). This water apparently moves 

up into the Four Corners confining unit, where it is pumped 

from oil and gas wells.

All water in the Four Corners aquifer system south of the 

Circle Cliffs divide and west of the Black Mesa and Monument 

divides that is not discharged along local flow paths to springs or 

pumped from wells ultimately discharges as springs into the 

canyon of the Little Colorado River or in Marble Canyon southwest of Lees Ferry, Ariz. (INTERA Environmental Consultants, 

Inc., 1984, p. 59). Some of the springs in this area are so low in 

dissolved solids (for example, Vasey's Paradise Spring, which has 

a dissolved-solids concentration of 163 mg/L) that they 

undoubtedly are sustained mostly by precipitation on plateaus 

bordering the canyons. Most of the springs, however, discharge 

water that has traveled farther from areas of recharge. Some of the 

water, in fact, may have traveled considerable distances through 

Pennsylvanian and Permian rocks and descended into the Four 

Corners aquifer system through fractures and faults associated 

with the East Kaibab monocline south and east of the Little

30,000

10,000

cc 1,000

cc 

0

o

s

100

8 10

Simulated ground water 

Bedstone 21-9 well water 

Vapor Caves Spring 

Yampa Spring 

Graves Spring

DS 

CA 

MG 

NA 

K

Dissolved solids

Calcium

Magnesium

Sodium

Potassium

HC03 Bicarbonate 

SO4 Sulfate 

CL Chloride 

Si02 Silica 

F Fluoride

0.5

DS CA MG NA K HCO3

DISSOLVED CONSTITUENTS

SO, CL SiO 2

FIGURE 95. Comparison of major ion chemistry modeled by CHILLER (Spycher and Reed, 1989b) and analyzed 

ground water from Leadville Limestone at Glenwood Springs, Colorado.
DISCHARGE, IN GALLONS PER MINUTE DISCHARGE, IN GALLONS PER MINUTE

c7r 

v

^ '

o *n r^r ^ iD p

^ rT 5' f

8 cn =^ r

a,s

o ..

11

-r- a ? ~*

2. r5 (3 E 8 ^

y i b £

c

00

^5 ^

cE^cc

c

n «,0 >n <D > t_

C

C m§ <-3 C

* 1I" g° i ~J M

? T)1 ^ °D 1i Z3 <3.3 O

D- c_3 1

"J 

Tl D m

3 ro

CD 

^ i 8 »

3 >

" 20

«

^

-<

1

A > >

NJ O 

O

CO -P* <J\ Oi - S § S § E

1

........... i

,_!

1

1

I

1

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1 1

j a D C 3 C

Z233 CD 

n tx - ^J 

^

W 33 S" 

Z

(V3

?

C<

Cnm

g -^ 

oO

ao

zm

"> 

S

CO >

S^

3000

1 1

1 1

§

1

I

Si

1

n § a

i

^ ^ 

^ 

m

fao 

m

i -S *2 

wo -

1

j S3

t

<

C

r

cr5 r

c

c

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/

(C 

rCc

rtr

c

c

c

cc
GROUND-WATER MOVEMENT B133

Colorado River (Cooley, 1976, p. 8-9). The combined flow of all 

springs discharging in the canyon of the Little Colorado River 

averages about 100,000 gal/min (223 ft3/s); Blue Spring, the 

largest single contributor, has a discharge of 42,000 to 

45,000 gal/min (Cooley, 1976, p. 5-8). The combined flow of all 

springs discharging in Marble Canyon is about 5,000 gal/min 

(11 ft3/s); Vasey's Paradise Spring (GA36-05-27b), the largest 

single contributor, has a discharge of 45 to 4,500 gal/min (Cooley, 

1976; McCulley, 1985). An undetermined amount of the water 

discharging in the canyon of the Little Colorado River and in 

Marble Canyon originates in areas to the south of the UCRB and 

represents outflow from the Lower Colorado River Basin.

EFFECT OF THE FOUR CORNERS 

CONFINING UNIT ON CIRCULATION

Despite its effectiveness in inhibiting ground-water movement, the Four Corners confining unit contains water in isolated 

layers and lenses. According to Charles Spencer (U.S. Geological 

Survey, oral commun., 1986), much of this water is connate. 

Water pumped from the Paradox Member of the Hermosa 

Formation in some of the oil and gas fields listed in table 20 may 

fit this interpretation. Unfortunately, any interpretation of the 

effect of the Four Corners confining unit on ground-water movement is hindered by a paucity of data. Sufficient data for interpretation exist only for the Paradox Basin and adjacent areas of 

southeastern Utah and in the Eagle Basin and adjacent areas of 

northwestern Colorado.

In the Paradox Basin and adjacent areas, including the 

Henry Mountains Basin, Monument Upwarp, and Blanding 

Basin, the prevailing direction of ground-water movement 

through the Four Corners confining unit appears to be vertical. 

Seemingly in contradiction, Hanshaw and Hill (1969, p. 277) 

presented a map of the potentiometric surface for the Paradox 

Member of the Hermosa Formation indicating a regionally 

interconnected flow system. This map, however, is based primarily on head data for the marine shelf facies of the Paradox 

Member, a sequence of interlayered carbonate rocks and sandstone at the top and margins of the member. The bulk of the 

Paradox Member consists of shale and evaporites, not carbonate 

rocks and sandstone. When head data are plotted for the entire 

Paradox Member, as was done by Thackston and others (1981, 

p. 214), there appear to be no geographic trends. Thus, a regionally interconnected flow system is not likely to exist in the 

Paradox Member.

Hydrochemical data for the Paradox Member support interpretations based on potentiometric-head data. According to 

Thackston and others (1981, p. 215), water in the Paradox 

Member is either a sodium chloride or calcium chloride type 

with substantial concentrations of magnesium and sulfate. The 

dissolved-solids concentration in this water ranges from 6,700 

to 440,000 mg/L (Rush and others, 1982, p. 45; Weir and others, 

1983a, p. 48 and 1983b, p. 40; Whitfield and others, 1983, p. 49; 

INTERA Environmental Consultants, Inc., 1984, p. 61), with no 

discernible geographical trends (Thackston and others, 1981,

p. 215). The salinity of the water and the apparent absence of 

geographical trends in the dissolved-solids concentration indicate that water in the Paradox Member largely is isolated from 

any active regional flow system (Thackston and others, 1981, 

p. 215).

Vertical flow through the Paradox Member, however, is 

suggested by differences in potentiometric head between overlying and underlying aquifers (for example, see Rush and 

others, 1982, p. 13; Weir and others, 1983a, p. 29) and by the 

similar chemistry of water in the Paradox Member and underlying Mississippian carbonate rocks in the Four Corners 

aquifer system. According to Hanshaw and Hill (1969, 

p. 285), this similarity indicates that the Four Corners aquifer 

system in the Paradox Basin is recharged primarily by water 

percolating down through the Paradox Member. Nearly all 

investigators in the Paradox Basin agree that vertical flow is 

restricted to discrete discontinuities, such as faults, joints, 

stratigraphic pinch-outs, the margins of igneous intrusions, or 

the edges of salt diapirs (for example, see Rush and others, 

1982, p. 12; Whitfield and others, 1983, p. 21). Springs issuing 

from the Paradox Member, including Tripp and Trimble Hot 

Springs (Barrett and Pearl, 1977, p. 241), Stinking Spring 

(Ritzma and Doelling, 1969, p. 106-107), and Onion Creek 

Spring (Rouse, 1967, p. 19), represent either water rising 

along faults in areas having upward head gradients or meteoric 

water descending through fractures in outcrops near which the 

springs issue. Typically, these springs have discharges of less 

than 100 gal/min.

Similar to the Paradox Member in the Paradox Basin, the 

Eagle Valley Evaporite in the Eagle Basin, White River Plateau, 

and Elk Mountains contains water traveling mostly along local 

flow paths. All known springs and wells that discharge water 

from the Eagle Valley Evaporite are located in stream valleys; 

with one exception, the concentration of dissolved solids in this 

water ranges from 250 to 2,600 mg/L (Rouse, 1967, p. 14; 

Brogden and Giles, 1976a; Giles and Brogden, 1976). Considering the topographic setting and chemical quality, most of the 

water appears to originate as precipitation on nearby outcrops; 

some may be seepage from channel alluvium.

Some of the water in the Eagle Valley Evaporite is water 

in transit between the Canyonlands aquifer and Four Corners 

aquifer system. This water has been in circulation longer and 

consequently is more saline than water typically discharging 

from the formation to springs and shallow wells. As an 

example, Big Spring at Dotsero, Colo., has a dissolved-solids 

concentration of 10,700 mg/L (lorns and others, 1964, 

p. 678-679). The water issuing from Big Spring probably 

originated on the White River Plateau, descended through the 

Leadville Limestone and other aquifers, then rose to the 

surface at the base of the uplift along flanking faults. As noted 

previously, saline springs discharging from the Leadville 

Limestone at Glen wood Springs, Colo., are attributable to 

downward percolation of meteoric water through the Eagle
B134 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

Valley Evaporite in uplifted areas to the south. As in the 

Paradox Member of the Hermosa Formation, vertical movement through the Eagle Valley Evaporite would be negligible 

without the existence of discrete discontinuities, such as 

faults and joints.

Extrapolating from the above information, it would appear 

that subregional flow in conjunction with the Canyonlands 

aquifer occurs in the upper part of the Four Corners confining 

unit, particularly in areas beyond the depositional extent of 

evaporite facies in the Eagle Valley Evaporite and Paradox 

Member of the Hermosa Formation. Within areas containing 

thick deposits of shale and evaporites, flow is dominated by 

water in transit between the Canyonlands aquifer and the Four 

Corners aquifer system along faults, joints, and other vertical 

discontinuities and by local, topographically controlled flow 

paths. In areas characterized by extensive faulting, such as the 

Verdure and Lisbon Valley grabens in Utah or the Cattle Creek 

graben in Colorado, considerable exchange of water between 

aquifers above and below the Four Corners confining unit can 

occur (URS Corporation, 1982, 1983; INTERA Environmental 

Consultants, Inc., 1984, p. 139-143).

CIRCULATION IN THE CANYONLANDS AQUIFER

Flow in the Canyonlands aquifer is greatly influenced by 

topography and facies changes within hydrogeologic units 

that make up the aquifer, more so than in the Four Corners 

aquifer system. Numerous small to moderately sized springs 

issuing from the Canyonlands aquifer in uplifted areas within 

a few miles of where water enters the aquifer (fig. 97) indicate 

that, in the Canyonlands aquifer, local flow paths are at least 

as important as subregional flow paths in the movement of 

ground water.

As in the Four Corners aquifer system, the Canyonlands 

aquifer is demarcated by the Continental Divide from the 

San Juan Mountains to the Sierra Madre and potentiometric 

divides elsewhere. In places, the potentiometric divides do not 

coincide with the political boundaries of the UCRB (pi. 11). 

These potentiometric divides are the Wind River-Northern 

Great Plains divide on the north, the Upper Colorado River 

Basin-Basin and Range divide on the west, the San JuanMonument divide on the southeast, and according to Cooley 

and others (1969, pi. 5), a divide possibly in the vicinity of the 

Mogollon Slope (location shown on pi. 1) on the south. Within 

the UCRB, potentiometric divides affecting the movement of 

water in the Canyonlands aquifer include the Uinta-Park and 

Tavaputs divides.

North of the Uinta-Park divide, water in the Canyonlands 

aquifer moves from peripheral highlands and the internal 

Rock Springs Uplift to the edges of structural basins, where it 

discharges to springs, is pumped from wells, or rises into 

Mesozoic and Tertiary rocks. Moderate to large springs, such 

as springs on La Barge Creek (SB29-117-0lad) and Hams 

Fork (SB26-18-13bad), and a few water wells deplete much

of the water recharged in the Overthrust Belt within a few 

miles of where the water enters the Canyonlands aquifer. 

Pinching out of the geologic units that comprise the 

Canyonlands aquifer a few miles south of Kendall, Wyo., and 

disruption of the aquifer by the Wind River fault have 

produced warm and cold springs at Kendall (fig. 98) with a 

combined discharge of about 8 ft3/s. These springs probably 

represent all of the water entering the Canyonlands aquifer 

from the Gros Ventre Range and Wind River Mountains along 

the northern boundary of the UCRB. Wells and springs, such 

as Olson Spring, in the Rawlins area also deplete water from 

the Canyonlands aquifer, and oil wells in the Great Divide 

Basin and Rock Springs Uplift (pi. 11 and table 20) withdraw 

large quantities of water from the aquifer. A cone of depression more than 1,000 ft deep apparently exists around the Lost 

Soldier-Wertz-Mahoney oil fields (pi. 11). Most of the water 

not pumped from wells or discharged from springs probably 

rises into Mesozoic or Tertiary rocks in the Green River, Great 

Divide, and Washakie Basins because of large upward head 

differences in these areas (pi. 12). Ultimately, some ground 

water flows out of the UCRB into the Hanna Basin through a 

gap between the Rawlins Uplift and Sierra Madre.

Between the Uinta-Park and Tavaputs divides, water in the 

Canyonlands aquifer moves from peripheral and internal highlands toward the Yampa and Green Rivers. Ground water 

recharged on the east side of the area flows toward the Piceance 

and Eagle Basins and then moves northwesterly to the Yampa 

River valley (Roger L. Hoeger, consulting hydrologist, written 

commun., 1969). Numerous small to moderately sized springs, 

such as Conundrum Hot Spring (Barrett and Pearl, 1977), intercept water recharged in the mountainous regions. In addition, 

numerous water wells completed mostly in the Maroon 

Formation in and near Glenwood Springs, Colo., discharge 

water from the Canyonlands aquifer at a combined rate of about 

900 gal/min (Wright Water Engineers, 1979). Ground water 

entering the Canyonlands aquifer on the west side of the area 

flows into the interior of the Uinta Basin and then moves northeast and east along the valleys of the Green and Duchesne 

Rivers toward the Yampa River (Hood and Fields, 1978, p. 34). 

Several large to very large springs, such as Warm Springs 

(UB01-08-30ddb), Ratliff Spring (SLD02-22-31adc), and 

Ashley Creek Springs (SLD03-20-01d), drain the Canyonlands 

aquifer at the base of the Uinta Mountains (Maxwell and others, 

1971, p. 15; Hood and others, 1976, p. 34-35). Also, water 

wells completed mostly in the Weber Sandstone in and near the 

Uinta Mountains discharge water from the aquifer at a 

combined rate of about 2,700 gal/min. By far, the largest 

pumpage from the Canyonlands aquifer between the Uinta-Park 

and Tavaputs divides comes from the Rangely and Ashley 

Valley oil fields. The combined water production from these 

two oil fields in December 1986 was nearly 36 ft3/s (table 20). 

Water not pumped from wells or discharged to springs along 

local flow paths rises into Mesozoic and Tertiary rocks in the
GROUND-WATER MOVEMENT B135

PICEANCE BASIN

WHITE RIVER PLATEAU 

Big Beaver North Fork

Creek White River

C'

10 15 20 KILOMETERS 

VERTICAL EXAGGERATION X8

EXPLANATION

Hydrogeologic units

Tertiary rocks

Mesozoic rocks

Canyonlands aquifer

Park City-State Bridge zone 

Weber-Ue Chelly zone 

Cutler-Maroon zone

Paradox-Eagle Valley subunit of 

Four Corners confining unit

Undifferentiated

- - Potentiometric surface for Canyonlands aquifer based on heads in 

Weber-De Chelly zone

1

Potentiometric surface for Canyonlands aquifer based on heads in 

Cutler-Maroon zone

Borehole

FIGURE 97. Geologic section from the Piceance Basin to the White River Plateau indicating the potentiometric surface 

for the Canyonlands aquifer and potential spring locations (location of section shown on pi. 11).
B136 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

FIGURE 98. Kendall Warm Springs 

(SB39-1 10-36) issuing from the 

Phosphoria Formation and flowing over 

terrace deposits into the Green River 

north of Pinedale, Wyoming.

vicinity of the Green and Yampa Rivers or flows toward the 

Jones Hole area at the eastern end of the Uinta Mountains 

(pi. 1 1). The combined flow of all springs in Jones Hole is 

37 ft3/s (Hood and others, 1976, p. 34-35).

South of the Tavaputs divide, water movement in the 

Canyonlands aquifer is influenced more strongly by topography 

than in any other part of the UCRB. West of the Green and 

Colorado Rivers, water in the Canyonlands aquifer moves from 

the San Rafael Swell, Circle Cliffs Uplift, High Plateaus, and 

Kaibab Plateau toward the valleys of the Price, San Rafael, 

Dirty Devil, Escalante, and Paria Rivers (Hood and Patterson, 

1984, p. 31-33). Between the Green and Colorado Rivers and 

the San Juan-Monument divide, water in the Canyonlands 

aquifer flows from the Uncompahgre Plateau, San Juan 

Mountains, Monument Upwarp, and Defiance Plateau toward 

the valleys of the Colorado, Green, Dolores, and San Juan 

Rivers (Cooley and others, 1969, pi. 5; Richter, 1980, fig. 10; 

Weir and others, 1983b, pi. 2; INTERA Environmental 

Consultants, Inc., 1984).

Some recharge to the Canyonlands aquifer south of the 

Tavaputs divide occurs around the edges of laccolithic mountains, whereas grabens in the area can be conduits for groundwater movement to or from the aquifer. In the Henry Mountains, 

for example, meteoric water infiltrates the Canyonlands aquifer 

along the fractured margins of igneous intrusions (Hood and 

Danielson, 1981, p. 32-36). Ultimately, however, this water 

ascends under a moderately upward hydraulic gradient into 

Mesozoic rocks in the Henry Mountains Basin (pi. 12). The 

Abajo Mountains, La Sal Mountains, and the intervening Sage 

Plain are considered to be a major recharge area for the 

Canyonlands aquifer in the Paradox Basin (Thackston and 

others, 1981; Weir and others, 1983b; Ackerman and Rush,

1984). This recharge may be augmented by upward leakage of 

water from the Four Corners aquifer system between the 

Paradox Valley and Sinbad Valley grabens because salt deposits 

normally present between the Canyonlands aquifer and Four 

Corners aquifer system have been plastically deformed and are 

thin or absent between Paradox Valley and Sinbad Valley (Weir 

and others, 1983b, p. 26). Gains in strearnflow by the Dolores 

River near Gateway, Colo., and by the Colorado River in the 

Salt Valley and Spanish Valley grabens might be, in part, also 

related to upward leakage. Conversely, leakage from the 

Canyonlands aquifer to the Four Corners aquifer system probably is occurring in the Big Gypsum Creek, Lisbon Valley, and 

Verdure grabens (Richter, 1980, p. 38; INTERA Environmental 

Consultants, Inc.. 1984, p. 165).

South of the Tavaputs divide, numerous small to moderately 

sized springs drain the Canyonlands aquifer wherever canyons 

are entrenched into plateau surfaces. At the western edge of the 

Uncompahgre Plateau, for example, Placerville Warm Spring 

issues from the Cutler Formation where the San Miguel River is 

incised into the plateau (fig. 99). Abetted by the large permeability of rocks that form most of the surface area in the 

Canyonlands region, numerous seeps and springs issue from the 

Cedar Mesa and White Rim Sandstones not far from where 

water infiltrates these formations (Sumsion and Bolke, 1972; 

Huntoon, 1977; Hand, 1979; Richter, 1980; Rush and others, 

1982). One such spring (SLD31-20-30add) occurs at the base 

of Angel Arch in the Needles district of Canyonlands National 

Park. The largest spring in the Monument Upwarp, Big Spring 

(SLD32-l8-29dbd). discharges into Gypsum Canyon at a rate 

of 125 gal/min (Huntoon. 1979). At the edges of the Defiance 

Plateau, numerous small to moderately sized springs issue from 

the De Chelly Sandstone (Davis and others, 1963).
GROUND-WATER MOVEMENT B137

FIGURE 99. Placerville Warm Spring 

(NMB44-ll-34ddd) issuing from travertine deposits at the base of an outcrop 

of the Cutler Formation at Placerville, 

Colorado. The spring location appears to 

be controlled by intersecting faults. On 

August 15, 1988, the date the spring was 

photographed, its discharge was 3.5 gallons per minute.

South of the Tavaputs divide and west of the San JuanMonument divide, very little water is withdrawn from the 

Canyonlands aquifer by wells. The only oil or gas fields in the 

area with significant water production from the Canyonlands 

aquifer, Upper Valley and Boundary Butte, discharged water at 

a combined rate of 643 gal/min in December 1986 (table 20). A 

few domestic and stock wells are completed in the Canyonlands 

aquifer in the San Miguel River valley (Ackerman and Brooks, 

1985), near Moab, Utah (Sumsion, 1971), in Canyonlands 

National Park and Natural Bridges National Monument 

(Sumsion and Bolke, 1972; Huntoon, 1977), and in the 

Defiance Plateau area (Davis and others, 1963; McGavock and 

others, 1966).

All water in the Canyonlands aquifer south of the Tavaputs 

divide, west of the San Juan-Monument divide, and north of the 

Mogollon Slope that is not discharged locally to wells or springs 

either rises into Mesozoic rocks in structurally low areas, such 

as the Castle Valley Sag, Paradox Basin, or Chinle Wash area 

(pi. 12), or flows out of the UCRB into canyons of the Colorado 

River (Marble Canyon) and Little Colorado River south of Lees 

Ferry, Ariz. A few small springs issue from the Coconino 

Sandstone and Supai Group in these canyons (Metzger, 1961, 

p. 128), but according to Cooley (1976, p. 8-9), the primary 

mechanism of discharge from the Canyonlands aquifer south of 

Lees Ferry is the downward movement of water along faults and 

fractures to the Four Corners aquifer system. Therefore, some 

of the water in springs issuing from the Four Corners aquifer 

system in Marble Canyon and the canyon of the Little Colorado 

River, such as Blue Spring, represents subregional discharge 

from the Canyonlands aquifer.

RATES OF GROUND-WATER MOVEMENT

If geochemical effects on ground-water movement, such as 

osmotic effects, density gradients, chemical reactions between 

the water and host rock, adsorption, and diffusion are ignored, 

rates of lateral ground-water movement can be estimated for 

two regional water-bearing zones, the Redwall-Leadville zone 

of the Madison aquifer and the Weber-De Chelly zone of the 

Canyonlands aquifer, based on the following equation:

V =

77 (25)

where

V = average linear velocity, in feet per day;

T - transmissivity, in feet squared per day;

/ = hydraulic gradient, in feet per foot;

<I> = porosity, dimensionless; and

b = thickness of aquifer, in feet.

Rates of ground-water movement through the RedwallLeadville and Weber-De Chelly zones represent maximum 

values for all Paleozoic rocks in the UCRB because no other 

hydrogeologic units are more permeable.

In the Redwall-Leadville zone of the Madison aquifer, 

lateral ground-water velocities are estimated to range from 

0.000001 to 0.001 ft/d in structural basins and from 0.001 to 

600 ft/d on the flanks and in the centers of uplifted areas 

(pi. 13). Rates of movement in excess of 10 ft/d are estimated to 

occur only in the southern part of the White River Plateau, 

where the rocks are cavernous and extensively faulted and 

fractured. At estimated rates of movement in this hydrogeologic
B138 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

unit, it would take ground water between 14,500 and 

14,500,000 years to travel 1 mi laterally in structural basins but 

only between 9 days and 14,500 years to travel 1 mi laterally in 

and on the flanks of uplifted areas.

Tn the Weber-De Chelly zone of the Canyonlands aquifer, 

lateral ground-water velocities are estimated to range from 

0.000005 to 0.001 ft/d in structural basins and from 0.001 to 

2 ft/d on the flanks and in the centers of uplifted areas (pi. 13). 

It would take water moving through this hydrogeologic unit 

between 14,500 and 2,900,000 years to travel 1 mi laterally in 

structural basins but only between 7.2 and 14,500 years to travel 

1 mi laterally in and on the flanks of uplifted areas.

In general, estimated average linear velocities indicate that 

water moving through the Paleozoic rocks along subregional 

flow paths from upland recharge areas to structural basins is 

slowed by decreasing transmissivity and hydraulic gradients in 

the direction of movement. In the center of structural basins, 

lateral ground-water movement essentially stagnates, and the 

prevailing direction of movement is upward into Mesozoic and 

Tertiary rocks.

DISCHARGE FROM THE PALEOZOIC ROCKS

Water in the Paleozoic rocks discharges to streams, springs, 

and wells, is consumed by evapotranspiration where the rocks 

are at or near land surface, seeps up into Mesozoic and Tertiary 

rocks in structural basins, or flows out of the UCRB into 

adjacent hydrologic basins. Discharge areas for the Paleozoic 

rocks are shown in figure 92. The greatest potential for 

discharge probably occurs in areas where head differences 

between the Canyonlands aquifer and the Four Corners aquifer 

system are more negative than -500 ft (pi. 12). These areas 

include valleys within the Overthrust Belt; the Green River, 

Great Divide, Washakie, Sand Wash, Eagle, Piceance, 

Blanding, Paradox, and San Juan Basins; topographically low 

parts of the Uinta Basin; the southern Henry Mountains Basin; 

upper Chinle Valley; Castle Valley; the San Rafael Desert; the 

Wasatch Plateau, lower reaches of the Yampa, Duchesne, 

Dolores, Green, Dirty Devil, and San Juan Rivers; Marble 

Canyon; and the canyon of the Little Colorado River.

SEEPAGE TO STREAMS AND SPRINGS

In areas where the Paleozoic rocks are at or near land 

surface, discharges to streams, springs, and seeps account for 

the largest ground-water outflow (see, for example, Hood and 

Fields, 1978). Discharges to springs and seeps commonly occur 

along local flow paths by one of four mechanisms: (1) Intersection of the land surface and potentiometric surface; (2) prevention of downward ground-water movement by negligibly 

permeable layers; (3) downdip changes in permeability within 

aquifers; or (4) fault severing of aquifers.

Most commonly, local discharge to springs and streams 

develops where deep canyons are incised below the potentiometric surface of an aquifer (fig. 97). Springs and seeps issue 

from fractures and caverns etched into cliffs bordering the 

canyons. Representative springs include Vasey's Paradise 

Spring in Marble Canyon (Cooley, 1976, p. 7); numerous 

springs in canyons draining the White River Plateau (lorns 

and others, 1964; Teller and Welder, 1983); and saline springs 

issuing along the Colorado River in Cataract Canyon 

(Thackston and others, 1981, p. 208). Discharges from these 

springs can fluctuate substantially in response to seasonal and 

annual variations in precipitation. The discharge of Vasey's 

Paradise Spring, for example, ranges from 45 to 

4,500 gal/min.

Ground water discharges locally from plateaus, buttes, 

and mesas in the Colorado Plateaus province where downward percolating ground water encounters a formation or 

layer with small to negligible permeability and is forced to 

flow laterally toward bounding escarpments. Such contact 

springs are numerous throughout the Monument Upwarp, on 

the flanks of the Defiance Plateau, and in the Grand Canyon 

(fig- 100).

On the homoclinal edges of uplifted areas, including the 

Rawlins Uplift, San Rafael Swell, Circle Cliffs Uplift, and 

Monument Upwarp, springs can develop in response to 

changes in permeability within an aquifer (Huntoon, 1983, 

p. 18-29). Typically, as aquifers become less fractured and 

more cemented away from the axes of uplifts, hydraulic 

conductivity decreases by several orders of magnitude. 

Water flowing downdip is rejected and either flows upward 

into overlying formations or discharges at springs (fig. 101).

Along the thrust-faulted margins of mountain ranges, 

including the southwestern flank of the Wind River 

Mountains and Gros Ventre Range, the north and south flanks 

of the Uinta Mountains, and the east flanks of the Salt River 

and Wyoming Ranges, aquifers typically are severed by 

faults, producing separate circulation systems in the hanging 

wall and foot wall (fig. 101). Large springs typically develop 

in the hanging wall where aquifers are thrust against formations with negligible permeability and water is forced to rise 

along the fault to the surface. Representative of this type of 

spring, Hogsback Spring on La Barge Creek near La Barge, 

Wyo., issues from the Lodgepole and Mission Canyon 

Limestones in the hanging wall of the Darby-Hogsback 

Thrust Fault (Lines and Glass, 1975). Measured discharges 

from this spring range from 4,000 to 5,500 gal/min (Lines and 

Glass, 1975; U.S. Geological Survey, unpub. data).

In most areas where the Paleozoic rocks are at or near 

land surface, spring discharges and seepage to channel alluvium along subregional and local flow paths enhance the 

discharge of through-flowing streams. Measured gains in 

streamflow in reaches where Paleozoic rocks compose all or
GROUND-WATER MOVEMENT B139

KAIBAB PLATEAU GRAND 

CANYON

NGVDof 1929

1,500

1,000

500 

FIGURE 100. Schematic representation of ground-water movement with respect to stratigraphy 

in the Kaibab Plateau in Arizona. (Modified from Metzger, 1961, pi. 14.)
B140 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

HOMOCLINAL 

MARGIN

MOUNTAIN 

UPLIFT

FAULTED 

MARGIN

Springs Springs

NOT TO SCALE

EXPLANATION 

Tertiary rocks 

Mesozoic rocks 

Paleozoic rocks 

Precambrian rocks

Fault Arrows indicate 

relative direction of 

movement

FIGURE 101. Schematic section showing potential spring locations on the flanks of an uplifted area.

(Modified from Huntoon, 1983, p. 14.)

most of the bedrock range from 0.61 to 7.0 ft3/s/mi; most 

gains range from 1 to 3 ft3 /s/mi (table 21). Streams with 

measured gains in discharge from Paleozoic rocks include 

the Colorado, Green, White, Blue, Eagle, Crystal, 

Fryingpan, Roaring Fork, San Rafael, Dolores (excluding 

Big Gypsum valley), and Uncompahgre Rivers (Rush and 

others, 1982, p. 34-42; Weir and others, 1983b, p. 34; 

Warner and others, 1985). The Duchesne River, where it 

leaves the western Uinta Mountains, is believed to gain 

streamflow from Paleozoic, Mesozoic, and Tertiary rocks 

(Hood, 1977, p. 14). The San Juan River, where it cuts 

through Paleozoic rocks in the Monument Upwarp, and the 

Yampa River, where it is incised into Paleozoic rocks in the 

eastern Uinta Mountains, also are believed to be gaining 

streams (Cooley and others, 1969, p. 44; Sumsion. 1976, 

p. 41). Small streams with perennial flow attributable to 

ground-water discharge from Paleozoic rocks include 

Maroon, Gypsum, Sweetwater, Deep, and Rifle Creeks 

(Teller and Welder, 1983; Warner and others, 1985). Total 

ground-water outflows to springs and streams from 

Paleozoic rocks within the Upper Colorado River Basin are 

known to be at least 1,113 ft3/s or about 810,000 acre-ft/yr 

(table 22). Undoubtedly, additional springs and seeps exist 

but have not been recorded.

WITHDRAWAL FROM WELLS

Water production from wells completed in the Paleozoic 

rocks is insignificant in most areas of the UCRB. In uplifted 

areas, where these rocks are at or near land surface, scattered 

wells provide water for domestic or stock use, usually at rates 

of less than 50 gal/min. However, a few of these wells 

discharge water at rates of 100 to 3,000 gal/min. Most of this 

production occurs in the McCoy, Aspen, Crested Butte, Telluride, Ouray, and Glenwood Springs areas of Colorado 

(Bryant, 1972; Hampton, 1974; Wright Water Engineers, 

1979; Giles, 1980; Ackerman and Brooks, 1985; City of 

Ouray, written commun, 1988); in and near the Uinta 

Mountains (Hood, 1976; Hood and others, 1976; Sumsion, 

1976); in the Overthrust Belt (Lines and Glass, 1975) and 

Rawlins Uplift (Berry, 1960); in and near the Defiance 

Plateau (Davis and others, 1963; McGavock and others, 1966; 

Levings and Farrar, 1977a); and in the Paradox Basin and 

Canyonlands areas of southeastern Utah (Feltis, 1966; Ritzma 

and Doelling, 1969; Sumsion, 1971; Sumsion and Bolke, 

1972; Hand, 1979; Richter, 1980; Weir and others, 1983a; 

Hood and Patterson, 1984). The total potential discharge of 

all water wells completed in the Paleozoic rocks as of 1988, 

that could be determined from published and unpublished 

data, is about 50 ft3 /s, or about 36,000 acre-ft/yr (table 22). 

Because some of these wells were not in operation when
GROUND-WATER MOVEMENT B141

visited between 1984 and 1988 and because others may be 

operating at less than their reported capacities, the current 

(1988) production of water from these wells is assumed to be 

less than 36,000 acre-ft/yr.

The largest withdrawals of water from Paleozoic rocks occur 

in conjunction with oil and gas production. As shown in tables 20 

and 22, oil and gas wells completed mostly in Paleozoic reservoirs in the Rangely, Lost Soldier-Wertz-Mahoney, greater

Aneth, Ashley Valley, Upper Valley, Brady, greater Lisbon, and 

23 smaller fields or consolidated fields produced water at a 

combined rate of about 63 ft3/s, or about 46,000 acre-ft/yr, in 

December 1986 (data from Petroleum Information Corporation, 

written commun., 1987). Actual water production from the 

Paleozoic rocks alone is unknown but has to be less than 

46,000 acre-ft/yr because some production from these fields is 

from Mesozoic rocks.

TABLE 21. Measured ground-water outflows to streams from Paleozoic rocks in the Upper Colorado River Basin,

excluding the San Juan Basin

Stream Reach

Base flow

Channel geology Gain Len§th 

(cubic feet of reach

per second) (miles)

Unit gain Inferred 

(cubic feet discharge from 

per second Paleozoic rocks 

per mile)

Source 

of data

Carbonate and clastic rocks

Colorado 

River

Eagle 

River

Sweetwater 

Creek

Deep 

Creek

Rifle 

Creek

Glenwood Canyon, 

Colo.

Headwaters to 

Avon, Colo.

Headwaters to 

Colorado River

Headwaters to 

Colorado River

Huffman Gulch to 

Rifle Falls, Colo.

Sawatch Quartzite to Belden Formation; some Precambrian rocks

Sawatch Quartzite to Minturn 

Formation some Precambrian 

rocks and till

Leadville Limestone to Eagle 

Valley Evaporite

Sawatch Quartzite to Belden 

Formation; minor Precambrian 

rocks

Leadville Limestone to Maroon 

Formation

30 17

83 38

27 16

11 14

28 4

1.8 All

2.2 More 

than half

1.7 All

.79 All

7.0 All

URS Corporation 

(1983)

Warner and others 

(1985)

Warner and others 

(1985)

Warner and others 

(1985)

Teller and Welder 

(1983)

Mostly clastic rocks

Colorado 

River

Colorado 

River

Colorado 

River

Crystal 

River

Cisco, Utah, to mouth 

of Green River

Mouth of Green 

River to Hite, Utah

Kremmling to 

Dotsero. Colo.

Headwaters to 

Carbondale. Colo.

Hermosa, Rico, and Cutler 

Formations and Mesozoic rocks

Hermosa Formation and Cutler Group

Eagle Valley Evaporite to State Bridge 

Formation; some Mesozoic and 

Precambrian rocks

Mostly Eagle Valley Evaporite to 

Maroon Formation; some Leadville

300 97

95 54

34 56

84 42

3.1 More 

than half

1.8 All

.61 Most

2.0 More 

than half

Rush and others 

(1982)

Rush and others 

(1982)

Warner and others 

(1985)

Warner and others 

(1985)

North Fork 

White 

River

Dolores 

River

Dolores 

River

Maroon 

Creek

Eagle 

River

Gypsum 

Creek

Trappers Lake to 

Buford, Colo.

Headwaters to 

Rico. Colo.

Gateway, Colo., 

to Cisco, Utah

Above Aspen 

Highlands Ski 

area, Colo.

Avon to 

Gypsum, Colo.

Headwaters to 

Gypsum, Colo.

Limestone. Mesozoic and igneous 

rocks and till

Mostly Morgan and Maroon 62 12 

Formations and Weber Sandstone; 

some stream and glacial alluvium

Mostly Hermosa, Rico, and Cutler 25 20 

Formations; some Mesozoic and 

Precambrian rocks

Cutler Formation and Mesozoic rocks 46 19

Mostly Maroon Formation; some 35 17 

Mesozoic and igneous rocks

Mostly shale and evaporites

Mostly Eagle Valley Evaporite; some 34 22 

Maroon Formation and Mesozoic 

rocks

Mostly Eagle Valley Evaporite; some 34 30 

Maroon Formation and till

5.2 

1.3

2.4 

2.1

1.6 

1.1

Most

More 

than half

About half 

Most

More 

than half

More 

than half

Boyle and others

(1984)

Warner and others

(1985)

Warner and others 

(1985)

Warner and others 

(1985)

Warner and others 

(1985)

Warner and others 

(1985)
B142 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

TABLE 22. Summary of known discharges from Paleozoic rocks to streams, springs, and wells in the Upper Colorado River Basin,

excluding the San Juan Basin, as of 1988

[<, less than or equal to; >, greater than or equal to]

Area

North of Uinta Mountains

and Axial Basin Arch

Between Uinta Mountains

and Uncompahgre Plateau

South of Uncompahgre

Plateau

Four Corners aquifer system and 

Four Corners confining unit

Discharge point

Springs in the Overthrust Belt

Springs in the Rawlins Uplift

Sheep Creek Spring (Uinta Mountains)

Water wells in the Rawlins Uplift

Miscellaneous gas-field pumpage 1

Subtotal (rounded)

Miscellaneous springs in the Uinta Mountains2

Split Mountain Warm Spring (Uinta Mountains)

Springs in the Elk Mountains

Bowles Hatchery Spring (Sawatch Range)

Springs and seeps in Glenwood Canyon

Springs on the White River Plateau

Seepage to Rifle Creek

Seepage to Sweetwater Creek

Seepage to Deep Creek

Seepage to Eagle River

Water wells in the McCoy area

Water wells in the Glenwood Springs area

Subtotal (rounded)

Springs in the San Juan Mountains

Water wells at Ouray, Colo.

Aneth oil-field pumpage

Lisbon oil- and gas-field pumpage

Miscellaneous oil- and gas-field pumpage

Subtotal (rounded )

Total (rounded)

Discharge 

(cubic feet 

per second)

27.2

0

6.5

1

.4

35

41.5

6.0

.9

2.5

30.2

5.8

27.7

3<27

3 11

3<46

425

54.5

228

2.2

1.5

5.0

.4

.1

9

272

Canyonlands aquifer

Discharge point

Springs in the Overthrust Belt

Springs in the Rawlins Uplift

Kendall Springs (Wind River Mountains )

Water wells in the Overthrust Belt

Lost Soldier- Wertz-Mahoney oil-field pumpage 1

Miscellaneous oil- and gas-field pumpage

Miscellaneous springs in the Uinta Mountains"

Jones Hole Springs (Uinta Mountains)

Springs in the Elk Mountains

Seepage to Crystal River

Seepage to North Fork White River

Seepage to Colorado River

Seepage to Maroon Creek

Seepage to Eagle River

Seepage to Yampa River

Water wells in and near the Uinta Mountains

Water wells in the Glenwood Springs area

Rangely oil-field pumpage

Ashley Valley oil-field pumpage

Springs in the San Juan Mountains and

Paradox Basin

Springs on the Monument Upwarp

Springs on the Defiance Plateau

Seepage to Colorado River

Seepage to Green River

Seepage to San Juan River

Seepage to Dolores River

Seepage to Dirty Devil and San Rafael Rivers

Water wells in San Miguel River Valley

Water wells in southeastern Utah

Water wells in the Defiance Plateau area

Miscellaneous oil- and gas-field pumpage

Discharge 

(cubic feet 

per second)

5.6

.4

7.8

1

19.2

.9

35

13.9

37.0

2.4

3>19

3>47

3>14

3<35

3<8

3<109

6

2

33.5

2.4

329

.6

1.5

.4

3>304

3<54

3<171

3>47

3±1

.1

4

5

1.5

590

954

Water production from oil and gas fields is for December 1986. Production rates may not be representative of average 1986 production because of monthly 

fluctuation. Production figures were obtained from Petroleum Information Corporation (written commun., 1987) for fields indicated on State maps to be 

producing mostly from Paleozoic reservoirs. Some fields produce from both the Four Corners aquifer system and the Canyonlands aquifer (both in Paleozoic 

rocks), and some produce from Paleozoic and Mesozoic rocks. Listings in this table reflect the dominant producing horizon. 

"Springs originating from streamflow losses to sinks immediately upstream are not included.

3Estimate based on ground-water seepage rates and approximate length of stream bordered by formations in either the Four Corners aquifer system or 

Canyonlands aquifer.

Reported discharges from three wells not known to be in use in 1987. 

"Average discharge of Redstone 21-9 geothermal well in 1984 aquifer test and Wright well. Both wells were not in use in 1987.
GROUND-WATER MOVEMENT B143

EVAPOTRANSPIRATION

Evapotranspiration is estimated to consume a large amount 

of the ground water in stream valleys and negligible amounts 

elsewhere. Because of a generally shallow water table along 

streams, water there is easily evaporated from soil, alluvium, 

and the uppermost layers of bedrock and is taken up readily by 

plants. Evapotranspiration around springs and in stream valleys 

where Paleozoic rocks are at or near the surface has been estimated in various studies to consume ground water at rates of 

between 0.5 and 2 ft/s per square mile of phreatophyte cover 

(table 23). In the northern Uinta Basin, more ground water is 

lost to evapotranspiration than is discharged to springs and 

streams (Hood and Fields, 1978).

LEAKAGE TO MESOZOIC AND TERTIARY ROCKS

Upward leakage of water from Paleozoic to Mesozoic and 

Tertiary rocks occurs around the edges and in the interior of 

structural basins (see Hampton, 1974). The largest proportion of 

upward movement occurs along discrete vertical discontinuities, such as faults, joints, stratigraphic pinch-outs, or the 

margins of igneous intrusions or salt diapirs (Rush and others, 

1982, p. 12; Whitfield and others, 1983, p. 21; INTERA 

Environmental Consultants, 1984, p. 139-143). Ultimately, 

ground water rising in structural basins discharges to throughflowing streams. The Green, Colorado, Yampa, Dolores, 

San Juan, and Dirty Devil Rivers are the principal loci for 

upward ground-water movement in structural basins (pi. 12). 

Because of uncertainties in the vertical hydraulic-conductivity 

values and vertical hydraulic gradients in the Paleozoic rocks of 

the UCRB, the rate of upward leakage from the Paleozoic rocks 

cannot be estimated. However, because the structural basins in 

which this leakage is believed to occur generally are arid, it is

estimated that leakage of water from Paleozoic rocks to 

Mesozoic and Tertiary rocks is the principal mechanism of 

recharge to the Mesozoic and Tertiary rocks in these areas.

INTERBASIN FLOW

Peripheral divides and hydraulic gradients prevent groundwater outflow from the study area in all but three places. 

Between the Rawlins Uplift and Sierra Madre, ground water 

flows out of the Great Divide Basin and into the Hanna Basin, 

part of the Northern Great Plains regional aquifer system (see 

Downey, 1984). In the southeastern corner of the study area, 

ground water flows under the Four Corners Platform into the 

San Juan Basin, which is part of the UCRB but was studied 

separately. While outflows to both the Hanna and San Juan 

Basins are believed to represent a small proportion of the annual 

ground-water discharge from the Paleozoic rocks of the UCRB, 

substantial quantities of ground water flow beneath the Kaibab 

Plateau and Marble Platform toward the confluence of the 

Colorado and Little Colorado Rivers (INTERA Environmental 

Consultants, Inc., 1984, p. 59), which is in the Lower Colorado 

River Basin.

According to Cooley (1976, p. 8), the combined flow of all 

springs and seeps in the Little Colorado River where it flows 

into the Colorado River ranged from 217 to 232 ft /s and averaged 223 ft3/s between 1950 and 1967. Some of this water 

represents local recharge from the Kaibab and Coconino 

Plateaus and Marble Platform or recharge from the 

San Francisco Plateau and Mogollon Rim (in the Lower 

Colorado River Basin), but a considerable amount of the water 

originates in the Defiance Plateau and Monument Upwarp areas 

of the UCRB (Cooley, 1976, p. 13).

TABLE 23. Ground-water consumption by evapotranspiration and seepage in areas where Paleozoic rocks 

are at or near land surface in the Upper Colorado River Basin

[<, Less than]

Ground-water outflow

Drainage area Location ., (square miles)

Area covered

by phreatophytes 

(square miles)

Evapotranspiration

(acre-feet 

per year)

(cubic feet per 

second per 

square mile)

Springs 

and seeps 

(acre-feet 

per year)

Source of data

Blanding-Durango area 4,600

Dolores River Basin 3,000

Moab-Monticello area 1,900

Green River-Moab area 3,000

Lower Dirty Devil River Basin 4,300

South flank of Uinta Mountains 5,200 

and northern Uinta Basin

Paradox Basin

21.9 27,000 1.7 

57.4 45,000 1.1 

23.4 32,000 1.9 

39.1 24,000 .86

Henry Mountains Basin 

93.8 30,000 .44 

Uinta Mountains and Uinta Basin 

347 160,000 .64

<200 Whitfield and others (1983, p. 47)

110,000 Weir and others (1983b, p. 37)

210,000 Weir and others (1983a, p. 44)

81,000 Rush and others (1982, p. 44)

75,000 Hood and Danielson (1981, p. 44)

130,000 Hood and Fields (1978, p. 18-19)
B144 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

Springs issuing from the Paleozoic rocks in Marble 

Canyon have a combined discharge of 11 ft /s, most of which 

comes from Vasey's Paradise Spring and two other springs 

(McCulley, 1985, p. 13). According to McCulley (1985), the 

outflow from springs in Marble Canyon is a mixture of water 

recharged west of the Colorado River on the Kaibab Plateau 

and water moving southwesterly from the Kaiparowits 

Basin.

The combined flow of all springs issuing from Paleozoic 

rocks in the canyon of the Little Colorado River and in 

Marble Canyon averages 234 ft3/s (170,000 acre-ft/yr). The 

preceding discussion indicates that a considerable amount of 

this springflow appears to be outflow from the UCRB to the 

Lower Colorado River Basin.

GROUND-WATER BUDGET FOR THE 

UPPER COLORADO RIVER BASIN

The ground-water budget for the UCRB cannot be 

determined accurately because of considerable uncertainty 

in determining several of the water-budget components. 

What is known is summarized in table 24. Resolution of 

uncertainties awaits additional data collection. At present, 

only a generalized model of the southern UCRB has been 

done by Weiss (1990). Detailed modeling of the entire 

UCRB is needed to verify or revise the information presented 

in this report.

TABLE 24. Estimated ground-water budget for the Paleozoic rocks 

of the Upper Colorado River Basin, excluding the San Juan Basin

[<, less than; >, greater than]

Water-budget component

Annual volume 

(acre-feet)

Inflows

Infiltration of precipitation

Interbasin ground-water flow

Outflows

Springs and seepage

Well withdrawals 

Water wells 

Oil and gas wells

Evapotranspiration

Leakage to Mesozoic and Tertiary rocks

Interbasin flow 

To Hanna Basin 

To San Juan Basin 

To Lower Colorado River Basin

<6,600,000 

1,000

>810,000

<36,000 

<46,000

Unknown 

Unknown

Unknown 

Unknown 

< 170,000

SUMMARY AND CONCLUSIONS

The Upper Colorado River Basin (UCRB), excluding parts 

of the San Juan Basin, is an area of about 100,000 mi2 . The 

UCRB is included in four physiographic provinces the 

Middle Rocky Mountains, Wyoming Basin, Southern Rocky 

Mountains, and Colorado Plateaus. Numerous uplifts and structural basins occur within each province, segmenting the UCRB 

into a variety of landforms, including mountains, plateaus, 

cuestas, hogbacks, mesas, plains, badlands, intermontane 

basins, river valleys, and canyons. The general surface of the 

UCRB lies at altitudes between 5,000 and 8,000 ft, but mountains and plateaus rise to altitudes as high as 14,500 ft, and 

streams are entrenched to altitudes as low as 3,100 ft.

In general, precipitation is distributed orographically. 

Average annual precipitation ranges from less than 6 inches in 

lowlands to more than 60 inches in some mountains but it fluctuates by more than 15 inches from year to year in some areas. 

Average precipitation exceeds 10 in/yr at altitudes above 

5,900 ft. At lower altitudes, most of the precipitation is 

consumed by evapotranspiration. At higher altitudes, most of 

the precipitation between April and September is consumed by 

evapotranspiration. Within the part of the UCRB covered by this 

study, precipitation averages about 15 in/yr.

The Colorado and Green Rivers are the principal streams in 

the UCRB. At its confluence with the Green River, the Colorado 

River has an average discharge of about 8,000 ft3/s, about 

1,400 ft3/s more than the average discharge of the Green River, 

even though the Green River at the confluence is longer and has 

a larger drainage area. Tributaries of the Colorado and Green 

Rivers with average discharges in excess of 500 ft3/s include the 

San Juan, Gunnison, Yampa, Roaring Fork, Dolores, White, 

New Fork, Duchesne, and Eagle Rivers. Eighty-two reservoirs 

in the basin have a combined storage capacity of 38 million 

acre-ft, 71 percent of which is in Lake Powell. Between 1963 

and 1982, an average annual reduction of 5,680 ft3/s in the 

discharge of the Colorado River where the river leaves the 

UCRB is attributable to construction of Glen Canyon Dam and 

Lake Powell. Leakage of water from Lake Powell into adjacent 

Paleozoic and Mesozoic rocks caused ground-water levels near 

the lake to rise by as much as 500 ft between 1963 and 1983.

Paleozoic rocks in the UCRB were classified in this report 

into 11 hydrogeologic units on the basis of the predominant 

lithologic and hydrologic characteristics of sedimentary 

sequences that persist throughout most of the basin. However, 

each of these sequences is heterogeneous because of various 

proportions of included rock types and various degrees of fracturing, solution channeling, cementation, and compaction. In 

general, all hydrogeologic units are most permeable and, therefore, have the largest sustained yields to wells and springs in 

uplifted areas and are least permeable in the interiors of structural basins. However, within comparable structural settings, 

there is little relation between permeability and depth of burial. 

The permeability of sandstone appears to be closely related to
SUMMARY AND CONCLUSIONS B145

porosity and, hence, grain size and the degree of cementation. 

In contrast, the permeability of carbonate rocks generally is not 

related to porosity but depends more on the presence of fractures and solution openings. Ranges overlap, but relative to 

confining units, aquifers characteristically have larger unitaveraged porosity, permeability, and hydraulic conductivity, 

larger composite transmissivity, and larger sustained yields to 

wells and springs.

The lower six hydrogeologic units composed of Paleozoic 

rocks constitute the Four Corners aquifer system. At the bottom 

of this aquifer system, the Flathead aquifer contains as much as 

800 ft of friable to firmly cemented sandstone and quartzite with 

minor carbonate rocks, shale, and conglomerate. Gradationally 

overlying the Flathead aquifer, the Gros Ventre confining unit 

consists of as much as 1,100 ft of sandy shale with subordinate 

sandstone and carbonate rocks. Above the Gros Ventre 

confining unit, the Bighorn aquifer consists of as much as 

3,000 ft of limestone and dolomite with subordinate shale and 

minor sandstone. Above the Bighorn aquifer, the Elbert-Parting 

confining unit consists of as much as 700 ft of variably 

interbedded carbonate rocks, sandstone, quartzite, shale, and 

anhydrite.

The uppermost aquifer in the Four Corners aquifer system 

is the Madison aquifer, which includes the Redwall-Leadville 

zone and the overlying Darwin-Humbug zone. The RedwallLeadville zone, which is as much as 2,500 ft thick, consists of 

limestone and dolomite, with minor sandstone and shale, and 

sparse to abundant chert layers, fragments, and nodules. Dolomite in the Redwall-Leadville zone increases in proportion to 

limestone basinward. The Darwin-Humbug zone, which is as 

much as 800 ft thick and limited in distribution, consists of variable proportions of limestone, dolomite, sandstone, shale, solution breccia, and gypsum.

The Redwall-Leadville zone of the Madison aquifer is the 

most transmissive hydrogeologic unit in the Four Corners 

aquifer system, and, consequently, hydrologic properties of this 

zone represent maximum values for the aquifers and confining 

units that make up the Four Corners aquifer system. Unitaveraged porosity in the Redwall-Leadville zone ranges from 

less than 1 to 11 percent; local-scale permeability (permeability 

determined by aquifer tests or calculated from laboratorydetermined values) ranges from 0.02 to 1,800 md; unit-averaged 

hydraulic conductivity ranges from 0.00005 to 200 ft/d; 

composite transmissivity ranges from less than 0.01 to 

47,000 ft2/d; storativity where the aquifer is at least 100 ft thick 

is estimated to range from 0.005 to 0.0002. Artesian (natural) 

yields from wells and springs typically range from less than 1 to 

10,000 gal/min.

Between the Four Corners aquifer system and the uppermost hydrogeologic units composed of Paleozoic rocks is the 

Four Corners confining unit, which in ascending order, includes 

the Belden-Molas and Paradox-Eagle Valley subunits. The 

Belden-Molas subunit, which is as much as 4,300 ft thick, 

consists of shale with subordinate carbonate rocks and

sandstone, and minor gypsum. The Paradox-Eagle Valley 

subunit generally is less than 9,700 ft thick, but small diapiric 

intrusions in the Eagle and Paradox Basins are estimated to be 

as much as 15,000 ft thick. The Paradox-Eagle Valley subunit 

consists of various proportions of carbonate rocks, shale, sandstone, gypsum-anhydrite, and halite. Unit-averaged porosity in 

the Four Corners confining unit ranges from less than 1 to 

6 percent; local-scale permeability ranges from 0.0012 to 

550 md; unit-averaged hydraulic conductivity ranges from 

0.00001 to 0.03 ft/d; composite transmissivity ranges from 

0.001 to 50 ft2/d. Artesian yields from wells and springs typically range from less than 1 to 150 gal/min.

The upper three hydrogeologic units composed of Paleozoic 

rocks form the Canyonlands aquifer, which in ascending order, 

includes the Cutler-Maroon, Weber-De Chelly, and Park CityState Bridge zones. The Cutler-Maroon zone, which is as much 

as 16,500 ft thick, consists of highly variable proportions of 

arkosic sandstone, quartz sandstone, conglomerate, shale, 

carbonate rocks, and gypsum-anhydrite. The Weber-De Chelly 

zone, which may be as much as 4,000 ft thick, consists of friable 

to firmly cemented quartz sandstone with minor shale and 

carbonate rocks. The Park City-State Bridge zone, which is as 

much as 800 ft thick, consists of highly variable proportions of 

shale, carbonate rocks, sandstone, gypsum-anhydrite, phosphorite, and chert.

Within the Canyonlands aquifer, the Weber-De Chelly zone 

transmits most of the water, but where this zone pinches out 

south and east of the Colorado River and north of the San Juan 

River, the Cutler-Maroon zone is the most transmissive part of 

the Canyonlands aquifer. Within the Canyonlands aquifer, unitaveraged porosity ranges from 1 to 28 percent; local-scale 

permeability ranges from 0.00078 to 380 md; unit-averaged 

hydraulic conductivity ranges from 0.00001 to 20 ft/d; 

composite transmissivity ranges from 0.00005 to 10,000 ff/d; 

and artesian yields from wells and springs range from less than 

1 to 2,900 gal/min. Storativity in the Weber-De Chelly zone 

where it is more than 100 ft thick is estimated to range from 

0.00003 to 0.001.

Recharge to the Paleozoic rocks occurs in peripheral and 

interior highlands primarily from precipitation on outcrops, 

infiltration of meteoric water through overlying strata, or 

leakage of runoff from stream channels. Recharge is possible in 

areas receiving as little as 10 inches of precipitation annually. 

The total direct and indirect recharge from precipitation is estimated to be less than 6,600,000 acre-ft/yr. On the western and 

northern edges of the UCRB, additional recharge is provided by 

ground-water inflows from structurally continuous areas separated from the UCRB by Quaternary surface-water divides. This 

recharge is estimated to be about 1,000 acre-ft/yr. In general, 

recharge areas are characterized by predominantly downward 

ground-water movement, losing streams, unsaturated rock, 

water-table conditions, and relatively fresh ground water. The 

largest potential for recharge exists where head differences 

between the Canyonlands and Madison aquifers are the most
B146 REGIONAL AQUIFER-SYSTEM ANALYSIS UPPER COLORADO RIVER BASIN, EXCLUDING SAN JUAN BASIN

positive. The principal recharge areas, on this basis, are the 

Wind River, Uinta, Elk, Abajo, and Elkhead Mountains; La Sal 

Mountains; the Sierra Madre, Park, and Sawatch Ranges; the 

Uncompahgre, Kaibito, Kaibab, and White River Plateaus; the 

High Plateaus region; topographically high areas in the Uinta 

and Piceance Basins; the Verdure, Lisbon Valley, and Big 

Gypsum Creek grabens in the Paradox Basin; and an arcuate 

area extending from the San Juan Mountains through the Sage 

Plain to the Monument Upwarp.

Because of highly variable topography within and peripheral to the UCRB, water in the Paleozoic rocks of the UCRB is 

forced to flow toward local and subregional outlets, rather than 

toward a single, regional discharge area. Although some water 

flows vertically through the Four Corners confining unit, the 

generally small permeability of this confining unit inhibits 

interchange of water between the underlying Four Corners 

aquifer system and the overlying Canyonlands aquifer. Within 

the Four Corners aquifer system and Canyonlands aquifer, 

water generally moves from structural and erosional highlands 

toward structural and fluvial basins. Ground-water movement in 

the Paleozoic rocks ultimately is directed mainly toward four 

areas the eastern Great Divide Basin (between the Rawlins 

Uplift and Sierra Madre), the confluence of the Yampa and 

Green Rivers, the San Juan Basin, and the confluence of the 

Colorado and Little Colorado Rivers. The fourth area is in the 

Lower Colorado River Basin, just south of the UCRB.

Average linear velocities of water in the Redwall-Leadville 

zone of the Madison aquifer and the Weber-De Chelly zone of 

the Canyonlands aquifer can be estimated from the distributions 

of composite transmissivity, hydraulic gradient, thickness, and 

unit-averaged porosity in these hydrogeologic units. Rates of 

lateral ground-water movement in the Redwall-Leadville zone 

of the Madison aquifer are estimated to range from 0.000001 to 

600 ft/d. At these rates, it would take between 14,500,000 years 

and about 9 days for water to travel 1 mi laterally. Rates of 

lateral ground-water movement in the Weber-De Chelly zone of 

the Canyonlands aquifer are estimated to range from 0.000005 

to 2 ft/d. At these rates, it would take between 2,900,000 and 

7.2 years for water to travel 1 mi laterally. Average linear velocities decrease from uplifted areas to structural basins as a consequence of decreasing hydraulic gradients and transmissivity 

basinward.

Water in the Paleozoic rocks discharges to streams, springs, 

and wells, is consumed by evapotranspiration where the rocks 

are at or near land surface, seeps upward into Mesozoic and 

Tertiary rocks in structural basins, or flows out of the UCRB 

into adjacent hydrologic basins. In general, discharge areas are 

characterized by upward ground-water movement, gaining 

streams, springs, flowing artesian wells, and brackish to briny 

ground water. The largest potential for discharge exists where 

head differences between the Canyonlands and Madison aquifers are the most negative. The principal discharge areas, on this 

basis, are the greater Green River Basin, the San Juan Basin, the 

southeastern Piceance and Uinta Basins, the eastern Paradox

Basin, the southwestern Henry Mountains Basin, the upper 

Chinle Valley, the San Rafael Desert, Castle Valley, and the 

lower reaches of the Colorado, Green, Yampa, Dolores, Dirty 

Devil, and Little Colorado Rivers.

In areas where Paleozoic rocks are at or near land surface, 

discharges to springs and streams are the largest ground-water 

outflow. Discharges to springs and streams commonly occur 

along local flow paths by one of four mechanisms: (1) Intersection of the topographic and potentiometric surfaces, (2) prevention of downward percolation by negligibly permeable layers, 

(3) downdip changes in permeability within aquifers, or (4) fault 

severing of aquifers. Springflow and seepage along subregional 

and local flow paths augment streamflow at rates commonly 

between 1 and 3 ft3/s per mile of channel bordered by Paleozoic 

rocks. Streams with measured or inferred gains in discharge from 

Paleozoic rocks include the Colorado, Green, San Juan, Yampa, 

White, Dolores, Crystal, Fryingpan, Roaring Fork, Eagle, Blue, 

Dirty Devil, San Rafael, and Uncompahgre Rivers and Maroon, 

Sweetwater, Deep, Gypsum, and Rifle Creeks. Total known 

outflows to springs and streams within the UCRB are estimated 

to equal or exceed about 810,000 acre-ft/yr.

Water production from Paleozoic rocks is negligible in most 

areas. In uplifted areas, where the rocks are at or near land 

surface, scattered wells provide water for domestic and stock 

use at rates of generally less than 50 gal/min, but a few wells 

discharge water at rates of 100 to 3,000 gal/min. If all water 

wells known to be completed in the Paleozoic rocks were in 

operation in 1988, their total production would be about 

36.000 acre-ft/yr. Considerable water production also occurs 

from oil and gas fields in which the principal reservoir is the 

Paleozoic rocks. The largest of these fields are the Rangely, Lost 

Soldier-Wertz-Mahoney, Aneth, Upper Valley, Brady, and 

Ashley Valley fields. In December 1986, the 30 oil and gas 

fields in the UCRB that produced mostly from reservoirs in the 

Paleozoic rocks yielded water at a combined rate of about 

46,000 acre-ft/yr.

Evapotranspiration is estimated to consume a large amount 

of ground water in stream valleys and negligible amounts elsewhere. Evapotranspiration around springs and in stream valleys 

where Paleozoic rocks are at or near land surface consumes 

ground water at estimated rates of 0.5 to 2 ft3/s per square mile 

of phreatophyte cover.

Leakage of ground water from the Paleozoic rocks to 

Mesozoic and Tertiary rocks is believed to occur around the 

edges and in the interior of structural basins, principally in the 

vicinity of vertical discontinuities such as faults, stratigraphic 

pinch-outs, or the edges of igneous intrusions or salt diapirs. 

This leakage, which could not be quantified because of insufficient data, may be the principal mechanism of recharge to 

Mesozoic and Tertiary rocks in the interior of deep, generally 

arid structural basins within the UCRB.

Peripheral ground-water divides and hydraulic gradients 

prevent ground-water outflow from the study area in all but 

three places. Between the Rawlins Uplift and Sierra Madre,
SELECTED REFERENCES B147

ground water flows out of the Great Divide Basin into the 

Hanna Basin. Ground water also flows between the Monument 

Upwarp and Defiance Plateau beneath the Four Corners 

Platform and into the San Juan Basin (a part of the UCRB that 

was excluded from this study). A third flow path from the 

UCRB directs water under the Kaibab Plateau and Marble 

Platform to the confluence of the Colorado and Little Colorado 

Rivers in the Lower Colorado River Basin. Outflows to the 

Hanna and San Juan Basins are unknown but are believed to be 

a small part of the annual ground-water budget for the Paleozoic 

rocks. However, springs issuing from Paleozoic rocks near the 

confluence of the Colorado and Little Colorado Rivers have a 

combined average discharge of 170,000 acre-ft/yr. Although 

some of this springflow represents water recharged locally and 

water moving along subregional flow paths from the Lower 

Colorado River Basin, a considerable amount of this springflow 

is outflow from the UCRB.

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__ USGS U-S- DEPARTMENT OF THE INTERIOR 

science for a changing world U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1411-B

Geographic features PLATE 1

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MONUMENT 

UPWARP

KAIPAROWITS 

BASIN

PRESTON 

BENCH

AREA EXCLUDED FROM STUDY

114'

41° ., 41°

39° I 39°

MIDDLE

ROCKY

MOUNTAINS

BASIN ANDJRANGE

L.

35° I

114'

104°

112°

110°

50

_L

100 MILES

_J

I I I

0 50 100 KILOMETERS

INDEX MAP SHOWING LOCATION OF UPPER COLORADO RIVER BASIN 

WITH RESPECT TO PHYSIOGRAPHIC PROVINCES

EXPLANATION

Topography

38°

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

107°

Mountain ranges Peak altitudes range from 10,000 to 14,000 feet above 

NGVD of 1929

Isolated mountains Peak altitudes range from 9,000 to 12,000 feet above 

NGVD of 1929

High plateaus Surface altitudes range from 8,000 to 12,000 feet above 

NGVD of 1929

Broad, dissected plateaus Surface altitudes range from 6,500 to 11,000 feet 

above NGVD of 1929 on plateau rims and from 5,000 to 6,500 feet in 

interior of plateaus. Plateau escarpments are ruggedly dissected and 1,000 to 

4,000 feet high

Stair-stepped plateaus Incised by canyons and surmounted by buttes and 

mesas. Surface altitudes generally between 4,000 and 8,000 feet above 

NGVD of 1929

Irregular topography Lowlands flanked by ridges, cuestas, and mesas that are 

incised by deep canyons. Altitudes range from 4,500 to 9,500 feet above 

NGVD of 1929

Rolling plains, hills, and low mountains Surface altitudes generally 6,000 to 

8,500 feet above NGVD of 1929. Hills and mountains rise 1,000 to 3,000 

feet above plains

Plains, badlands, and mesas with isolated hills and mountains Surface 

altitudes range from 6,000 to 7,500 feet above NGVD of 1929 north of the 

Uinta and Piceance Basins; from 4,000 to 7,000 feet above NGVD of 1929 

south of the Uinta and Piceance Basins

mc

35'

110°

1:2,000,000

25

I

50

I

75 100 MILES

J

25

r

50

~T

75

_____

I

100 KILOMETERS

TOPOGRAPHY

111° 110

25

109°

1:2,000,000

50 75 100 MILES

25 50 75 100 KILOMETERS

CITIES, RIVERS, PHYSICAL FEATURES, NATIONAL PARKS, AND INDIAN RESERVATIONS

Base from U.S. Geological Survey 

U.S. base map, 1:2,500,000

GEOGRAPHIC FEATURES OF THE UPPER COLORADO RIVER BASIN AND VICINITY IN ARIZONA, COLORADO, NEW MEXICO, UTAH, AND WYOMING

By

Arthur L. Geldon 

2002
^USGS __ U.S. DEPARTMENT OF THE INTERIOR 

science fora changing world U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1411-B

Porosity and hydraulic conductivity of the Redwall-Leadville zone PLATE 2

Geldon. A.L., 2002. Hydrologic properties and ground-water flow systems of the Paleozoic rocks in the Upper 

Colorado River Basin in Arizona. Colorado. New Mexico. Utah, and Wyoming, excluding the San Juan Basin

110°

43'

42

- 40°

AREA EXCLUDED FROM STUDY

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

25

I

1:2,000,000 

50 75

I

108°

100 MILES

I I I I 

25 50 75 100 KILOMETERS

UNIT-AVERAGED POROSITY

110°

43'

 ,V40°

i '

' /

^ 1 / ' ^ ' ^ , i

1 ray/ ^ d tataJH^ ^ , vX

-~' *. , - - V-~- A

/ - . i 7 - -iJ- - _/

AREA EXCLUDED FROM STUDY

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

25

I

1:2,000,000 

50 75 100 MILES

25

I 

50

I 

75 100 KILOMETERS

UNIT-AVERAGED HYDRAULIC CONDUCTIVITY

EXPLANATION

Area where the Redwall-Leadville zone is missing because of erosion or 

nondeposition

Unit-Averaged Porosity

Line of equal estimated unit-averaged porosity Location is approximate. 

Interval is 1 percent

4.4

5.4

Site at which unit-averaged porosity was estimated as the mean of 

laboratory-determined values in a borehole interval at least 100 feet 

thick and representative of the lithology of the Redwall-Leadville zone 

at the site Number shown is mean porosity in the interval, in percent

Site at which unit-averaged porosity was estimated as the median of

geophysically determined values in a borehole interval at least 100 feet 

thick Number shown is median porosity in the interval, in percent

Unit-Averaged Hydraulic Conductivity

Relative unit-averaged hydraulic conductivity

Large

Moderate

Small

-0.01- Line of equal estimated unit-averaged hydraulic conductivity Dashed 

where approximately located. Interval, in feet per day, is variable

Limit of data 

Data sites

Site at which estimate was based on permeability determined by a drill-stem 

test

Site at which estimate was based on the mean of laboratory-determined 

permeability values in a borehole interval

Site at which estimate was based on the average of hydraulic-conductivity 

values determined by pressure-injection tests in a borehole interval

Site at which estimate was based on transmissivity determined by a pumping 

or flowing-well test

Base from U.S. Geological Survey 

U.S. base map, 1:2,500,000 UNIT-AVERAGED POROSITY AND HYDRAULIC CONDUCTIVITY OF THE REDWALL-LEADVILLE ZONE OF THE MADISON AQUIFER IN THE UPPER COLORADO RIVER BASIN AND VICINITY

IN ARIZONA, COLORADO, NEW MEXICO, UTAH, AND WYOMING

By

Arthur L. Geldon 

2002
__ USGS U.S. DEPARTMENT OF THE INTERIOR

science for a changing world U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1411-B

Transmissivity of and maximum yields from the Redwall-Leadville zone PLATE 3

Geldon, A.L., 2002, Hydrologic properties and ground-water flow systems of the Paleozoic rocks in the Upper 

Colorado River Basin in Arizona. Colorado. New Mexico, Utah, and Wyoming, excluding the San Juan Basin

42

AREA EXCLUDED FROM STUDY

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

107C

25

I

1:2,000,000

50

I______

75

I

108°

100 MILES

I I I I 

25 50 75 100 KILOMETERS

COMPOSITE TRANSMISSIVITY

43'

1,000

,^.40°

VASEYS

PARADISE

SPRING

< 10ft Ci \ // <> 

H^<j <-°^ (NcHilp CREEkJ 

-f Ke'- i-,' v SPRING /

WYOMING

\j£OLORAD

/ '^ i 

<^2<a-\

vx St^A^l - , \

I // *£' *~'*v

\\*J WW'^-/>,.J ?r,Ti,/,7 C C ,"'.

x .^--

' / *.,'-.<->

^ N^-Garfield ^-X-Garfield .

:-^-ii3 

', ' /' ' "

\ . \ \ \

^, \\\

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

'l! '\'\:

\ \

AREA EXCLUDED FROM STUDY

BLUE-" V 

SPRING

25

I

1:2,000,000 

50

I____

75

I

108°

100 MILES

n i i i

25 50 75 100 KILOMETERS

MAXIMUM YIELDS

EXPLANATION

Area where the Redwall-Leadville zone is missing because of erosion or 

nondeposition

Composite Transmissivity

Relative composite transmissivity

Large

Moderate

Small

-10- Line of equal estimated composite transmissivity Location is approximate. 

Interval, in feet squared per day, is variable

Limit of data 

Data sites

Site of pumping or flowing well test from which transmissivity was calculated by 

analysis of drawdown- or recovery-versus-time data

Site of pumping test with specific capacity data from which transmissivity was 

estimated

Maximum Yields

 wo--

Relative maximum yield

Large

Moderate

Small

Line of equal maximum yield from wells and springs under artesian 

conditions Dashed where approximately located. Interval, in gallons per 

minute, is variable

Data sites

Borehole Yield is flow into or from well

Spring Labeled if discharge equals or exceeds 1,000 gallons per minute. 

Largest discharge (Blue Spring) is 45,000 gallons per minute

Base from U.S. Geological Survey 

U.S. base map, 1:2,500,000 COMPOSITE TRANSMISSIVITY OF AND MAXIMUM YIELDS FROM THE REDWALL-LEADVILLE ZONE OF THE MADISON AQUIFER IN THE UPPER COLORADO RIVER BASIN AND VICINITY

IN ARIZONA, COLORADO, NEW MEXICO, UTAH, AND WYOMING

By

Arthur L. Geldon 

2002
uses U.S. DEPARTMENT OF THE INTERIOR 

science for a changing world U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1411-B

Hydraulic conductivity and transmissivity of the Paradox-Eagle Valley subunit PLATE 4

Geldon, A.L., 2002, Hydrologic properties and ground-water flow systems of the Paleozoic rocks in the Upper 

Colorado River Basin in Arizona. Colorado, New Mexico, Utah, and Wyoming, excluding the San Juan Basin

43

-;40°

^i' 'V/?

1 w. -s__£. I ^ /_

 , v , i -v' -^ v

^ ^>;cxO ^ :::

r

^ig: :-v. -;---:.(----

UTAH 

RIZONA

AREA EXCLUDED FROM STUDY

110°

42

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

X - - V ' " 'J ' N \

~ ' x -v - _'/ - \

^^\^L^^ \

, , ^^^oai) ; \

^,v ' , , i, t'^Vx ;, ,

-. - s^~t* * 

_ x- \'X- x 'X~ _»

->^>^ '^'x- /'v''^V/"V^^ ; ; /.it/

^\T- - ',' *-,'. ^ ^ > - '_' ^ .>V- - - '_' ^ . - ^x--i

/^f '> i x / / * s

' ^-TL^ri ' f ~* ' ~:^~

-.' - C^i-Sy^r^-^^

AREA EXCLUDED FROM STUDY

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

107°

25

1:2,000,000 

50 75

I

100 MILES

I

25

1:2,000,000

50

I______

75 100 MILES

25 50 75 100 KILOMETERS

UNIT-AVERAGED HYDRAULIC CONDUCTIVITY

\ I I I 

25 50 75 100 KILOMETERS

COMPOSITE TRANSMISSIVITY

EXPLANATION

Area where the Paradox-Eagle Valley subunit is missing because of erosion 

or nondeposition

Unit-Averaged Hydraulic Conductivity

Relative unit-averaged hydraulic conductivity

Moderate 

Small

-0.01- Line of equal estimated unit-averaged hydraulic conductivity Location is 

approximate. Interval, in feet per day, is variable

Limit of data 

Data sites

Site at which unit-averaged hydraulic conductivity was estimated from hydraulic 

conductivity of intervals in a borehole. Interval hydraulic-conductivity values 

were calculated from transmissivity values determined from slug tests

Site at which unit-averaged hydraulic conductivity was estimated from

permeability values obtained from drill-stem tests or laboratory measurements 

for borehole intervals representative of the Paradox-Eagle Valley subunit 

where the data were obtained

Composite Transmissivity

Relative composite transmissivity

Moderate 

Small

 70- Line of equal estimated composite transmissivity Location is approximate. 

Interval, in feet squared per day, is variable

Limit of data

Base from U.S. Geological Survey 

U.S. base map, 1:2,500,000 UNIT-AVERAGED HYDRAULIC CONDUCTIVITY AND COMPOSITE TRANSMISSIVITY OF THE PARADOX-EAGLE VALLEY SUBUNIT OF THE FOUR CORNERS CONFINING UNIT

IN THE UPPER COLORADO RIVER BASIN AND VICINITY IN ARIZONA, COLORADO, NEW MEXICO, UTAH, AND WYOMING

By

Arthur L. Geldon 

2002
_ USGS U.S. DEPARTMENT OF THE INTERIOR 

science for a changing world U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1411-B

Porosity and hydraulic conductivity of the Cutler-Maroon zone PLATE 5

Geldon, A.L., 2002, Hydrologic properties and ground-water flow systems of the Paleozoic rocks in the Upper 

Colorado River Basin in Arizona, Colorado, New Mexico, Utah, and Wyoming, excluding the San Juan Basin

J:'''^:^J^\'<'Y\

\ h ' '/.- -/\>X' ' 'V- - \ , A. \\J^ - .-^ . Y- X, 'oxv--, - \

r ii r ". » v <. -^ _-> \S ^ ' I-: N

43°

108°

^^:>J ^W$:m&mm^ ftVtt^,^^ : - 1%^: \ :-; -:: ~C^^^=f- 

*£&£*&; 

>-^-> I > - i 

* 

. 

. \ ,W\ 

f s I I 

- 

y 

: ; /. 

'I 

r ' x 

I / 

: ld 

W 

x~f^^

^ J I / A'vA^-, A'V;V'', ,\<x*'s£\ A'V;. ^v^',;/'V/^;,;^"i-^^',^''"i-,Vx;.

 ^ I *" '^ll~^.*^~ " ^ ' ~ N ' ~ ' V ' ~ N.

4.3

v7

-Hoc-./fpnni41 C

I /\l ' \

I / I

-10- ^

?, ^ \ v ~>^y^ ' ; T ' x V N i-y x ^--o-, ii - i ' / ~' r

/'-' fio't S\jlr^ur^ir^s^J^-V^^--'/ 

 ^ ^ . v ^ /L ,\ _\. x - ^ , * A(

106°

39°

^

I Gre

38°

Monticell. &

107°

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

Lake -\ t 

Powell tt^S^

uranc

37°

^

~T

Pagosa 

Springs,

Navajo 

, Reservoir

37°

y. ,ita fFajfrnington

AREA EXCLUDED FROM STUDY

109°

J

-' 36°

25

I

1:2,000,000

50 75

I

108°

100 MILES

\ I T I 

25 50 75 100 KILOMETERS

UNIT-AVERAGED POROSITY

42

(_JWYOMfN 

V--i;-x/Vio7° ^ ^//r---<^

P7 /, '//X i/ I \ .

; s

AREA EXCLUDED FROM STUDY

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

1 125x- '

25

I

1:2,000,000

50 75

I

100 MILES

i i r i

25 50 75 100 KILOMETERS

UNIT-AVERAGED HYDRAULIC CONDUCTIVITY

EXPLANATION

Area where the Cutler-Maroon zone is missing because of erosion or 

nondeposition

Unit-Averaged Porosity

Line of equal estimated unit-averaged porosity Location is approximate. 

Interval is 1 percent

6.6

Site at which unit-averaged porosity was estimated from the mean of 

laboratory-determined values in borehole intervals representative of 

the entire Cutler-Maroon zone at the site Number shown is the mean 

porosity of the interval, in percent

Unit-Averaged Hydraulic Conductivity

Relative unit-averaged hydraulic conductivity

Large

Moderate

Small

-001- Line of equal estimated unit-averaged hydraulic conductivity Location 

is approximate. Interval, in feet per day, is variable

Limit of data

Data sites Number shown is hydraulic conductivity or average hydraulic 

conductivity at the site, in feet per day

Site at which estimate was based on permeability determined by one or more 

drill-stem tests

Site at which estimate was based on the mean of laboratory-determined 

permeability values in a borehole interval

Site at which estimate was based on the median of geophysically determined 

porosity values in a borehole interval

Site at which estimate was based on the average of hydraulic-conductivity 

values determined by pressure-injection tests in a borehole or boreholes

Site at which estimate was based on the transmissivity determined from a 

pumping test

Site at which estimate was based on the transmissivity determined from a 

bailing test

Site at which estimate was based on the transmissivity determined from an 

"airlift test"

Base from U.S. Geological Survey 

U.S. base map, 1:2,500,000 UNIT-AVERAGED POROSITY AND HYDRAULIC CONDUCTIVITY OF THE CUTLER-MAROON ZONE OF THE CANYONLANDS AQUIFER IN THE UPPER COLORADO RIVER BASIN AND VICINITY

IN ARIZONA, COLORADO, NEW MEXICO, UTAH, AND WYOMING

By

Arthur L. Geldon 

2002
__ uses _ U.S. DEPARTMENT OF THE INTERIOR 

science fora changing world U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1411-B

Transmissivity of and maximum yields from the Cutler-Maroon zone PLATE 6

Geldon. A.L, 2002. Hydrologic properties and ground-water flow systems of the Paleozoic rocks in the Upper 

Colorado River Basin in Arizona, Colorado. New Mexico, Utah, and Wyoming, excluding the San Juan Basin

43

 40°

C^::-^\#FX-

^x^^'^-^;

ir( ^OMfNG

jr'>^x ;/'~',-':: ,v^~<

ty :f- -: v\ L-V'-X' :lA^

/^ ' 

AREA EXCLUDED FROM STUDY

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

107°

25

I

1:2,000,000

50

I______

75

I

100 MILES

I I I I 

25 50 75 100 KILOMETERS

COMPOSITE TRANSMISSIVITY

110°

43

o'7

42

'-; ' '-^^rrx--- V^: f-; ':-.-V-'-; ':-.\J f 

^^rlT/^^V:^-;^;^^^/

AREA EXCLUDED FROM STUDY

39

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

112

107 C

25

I

1:2,000,000

50 75

I

108°

100 MILES

_I

1 I I I 

25 50 75 100 KILOMETERS

MAXIMUM YIELDS

-w-

 

o

EXPLANATION

Area where the Cutler-Maroon zone is missing because of erosion or 

nondeposition

Composite Transmissivity

Relative composite transmissivity

Large

Moderate

Small

Line of equal estimated composite transmissivity Location is approximate. 

Interval, in feet squared per day, is variable

Limit of data

Data sites Number shown is transmissivity, in feet squared per day 

Site at which transmissivity was determined from a pumping test 

Site at which transmissivity was determined from a bailing test

A Site at which transmissivity was estimated from pressure injection tests and 

thickness determined from a cross section

Maximum Yields

Relative maximum yield

Large

Moderate

Small

Line of equal maximum yield from wells and springs under artesian 

conditions Dashed where approximately located. Interval, in gallons per 

minute, is variable

Limit of data 

Data sites

Well Discharge during a drill-stem test, flow to a well during drilling, or flow 

from a well after completion is indicated

Spring Discharge is an average at some sites. The largest springs mentioned 

in the text are shown

wo--

Base from U.S. Geological Survey 

U.S. base map, 1:2,500,000 COMPOSITE TRANSMISSIVITY OF AND MAXIMUM YIELDS FROM THE CUTLER-MAROON ZONE OF THE CANYONLANDS AQUIFER IN THE UPPER COLORADO RIVER BASIN AND VICINITY

IN ARIZONA, COLORADO, NEW MEXICO, UTAH, AND WYOMING i 

; By

Arthur L. Geldon 

2002
USGS U.S. DEPARTMENT OF THE INTERIOR

science fora c/ranffins worW U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1411-B

Porosity and hydraulic conductivity of the Weber-De Chelly zone PLATE 7

Geldon, A.L, 2002, Hydrologic properties and ground-water flow systems of the Paleozoic rocks in the Upper 

Colorado River Basin in Arizona. Colorado, New Mexico, Utah, and Wyoming, excluding the San Juan Basin

 W-XvV..^

°i^^^W2&A::>-

FIERCOLOBA RIVERBASIN

rfi ////- ' -'- i V ; - - 'J \(\ 6t« / \ -Wt^-*-0"

4$F$ir^^ N P-V'-Yf-iw-i^'X? \\\ V-^-..'---^

 1

AREA EXCLUDED FROM STUDY

107°

1:2,000,000

25 -i-H25 50

50 75 100 MILES

i i 

75 100 KILOMETERS

UNIT-AVERAGED POROSITY

43°

 -' 40°

AREA EXCLUDED FROM STUDY

BOUNDARY OF

UPPER COLORADO

R IVER BASIN

25 50 75 

j______|______L 

i I T I 

25 50 75 100 KILOMETERS

UNIT-AVERAGED HYDRAULIC CONDUCTIVITY

EXPLANATION

Area where the Weber-De Chelly zone is missing because of erosion or 

nondeposition

Unit-Averaged Porosity

-5 Line of equal estimated unit-averaged porosity Dashed where approximately 

located. Interval is 5 percent

Data Sites

Site at which esimate was based on mean porosity of samples from a borehole 

interval

Site at which esitmate was based on mean porosity of samples from an outcrop

Site at which estimate was based on median porosity in a borehole interval 

determined by a combination of sonic, neutron, and density logs

Site at which estimate was based on mean porosity in a borehole interval 

determined by a sonic log

Site at which estimate was based on permeability or hydraulic conductivity 

using equations 7 and 11 and equations in table 3

Unit-Averaged Hydraulic Conductivity

Relative unit-averaged hydraulic conductivity

Large

Moderate

Small

1 - - Line of equal estimated unit-averaged hydraulic conductivity Dashed 

where approximately located. Interval, in feet per day, is variable

Data Sites Labeled sites are discussed in the text or listed in table 15

x Site at which estimate was based on median porosity in a borehole interval, as 

determined from geophysical logs

 Site at which esitmate was based on the mean laboratory-determined 

permeability of samples from an outcrop or borehole interval

A Site at which estimate was based on permeability determined by one or more 

drill-stem tests

+ Site at which estimate was based on the average of pressure-injection tests in a 

borehole interval

* Site at which estimate was based on transmissivity determined by a pumping, 

flowing-well, or bailing test

Base from U.S. Geological Survey 

U.S. base map, 1:2,500,000

UNIT-AVERAGED POROSITY AND HYDRAULIC CONDUCTIVITY OF THE WEBER-DE CHELLY ZONE OF THE CANYONLANDS AQUIFER IN THE UPPER COLORADO RIVER BASIN AND VICINITY

IN ARIZONA, COLORADO, NEW MEXICO, UTAH, AND WYOMING

By

Arthur L. Geldon 

2002
__ U.S. DEPARTMENT OF THE INTERIOR

science for a changing world U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1411-B

Transmissivity of and maximum yields from the Weber-De Chelly zone PLATE 8

Geldon, A.L., 2002, Hydrologic properties and ground-water flow systems of the Paleozoic rocks in the Upper 

Colorado River Basin in Arizona. Colorado, New Mexico, Utah, and Wyoming, excluding the San Juan Basin

43'

42

Kamas 

well

'- ':.-'V*:'"-3.-??

'if- '^ ( C-V '-~-'*' -'? -'

x )'~-\ 1 ' ^ ' - - ' "Sitverton _' ".'^ - ) I ,~/v - -s', .~,9r

jfe? I a

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

4,70(5

Leupp 

well

100 MILES 

~~l J

100 KILOMETERS

COMPOSITE TRANSMISSIVITY

43

Hams

Fork

Spring

Warm Springs

Flaming Gorge

ReseruoirJ) Stauff.r WYOMING 

OLORAD

loosevelt \ /Ashley

AREA EXCLUDED FROM STUDY

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

112

25

I

1:2,000,000

50

I______

75

I

100 MILES

I I I I 

25 50 75 100 KILOMETERS

MAXIMUM YIELDS

EXPLANATION

Area where the Weber-De Chelly zone is missing because of erosion or 

nondeposition

Composite Transmissivity

Relative composite transmissivity

Large

Moderate

Small

-10 Line of equal estimated composite transmissivity Location is approximate. 

Interval, in feet squared per day, is variable

6,000

Aquifer test from which transmissivity was determined Number shown is 

transmissivity, in feet squared per day. Labeled wells are listed in table 15

Maximum Yields

wo--

Relative maximum yield

Large

Moderate

Small

Line of equal yield from wells and springs under artesian conditions 

Dashed where approximately located. Interval, in gallons per minute, is 

variable

Limit of data 

Data sites

Borehole Discharge during a drill-stem test, flow into a well during drilling, 

or flow from a well after completion is indicated. Wells mentioned in text 

are labeled

Spring Moderate to large springs mentioned in the text and other large 

springs are labeled

Base from U.S. Geological Survey 

U.S. base map, 1:2,500,000 COMPOSITE TRANSMISSIVITY OF AND MAXIMUM YIELDS FROM THE WEBER-DE CHELLY ZONE OF THE CANYONLANDS AQUIFER IN THE UPPER COLORADO RIVER BASIN AND VICINITY

IN ARIZONA, COLORADO, NEW MEXICO, UTAH, AND WYOMING

By

Arthur L. Geldon 

2002
USGS U.S. DEPARTMENT OF THE INTERIOR

science fora changing world U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1411-B

Porosity and hydraulic conductivity of the Park City-State Bridge zone PLATE 9

Geldon, A.L., 2002. Hydrologic properties and ground-water flow systems of the Paleozoic rocks in the Upper 

Colorado River Basin in Arizona. Colorado. New Mexico. Utah, and Wyoming, excluding the San Juan Basin

43'

42

1 / t t-lar-jtij oot-vf i

(^OJflgsO^ffl

'A

1-6v I'\ j .-x=rtjv\ ' " -

^ X^-^-fv;/^-^ 

"-'/''"' Xx ~»V~R> - ~ *' °~' "' ^^^^T^^^^^lr 

J^-'^

- if N \ : x \- Of \ : V- ~ x \ : ^tf*. \^>^^(^r^ \ S

~, ,' ' _- V VXS 

^^X - ~ .x - ,vNx .-. V

 \' ^^^^V'x^^s^^^^crx; ' :y ^ ^B^H3 u.: -: -.- ^^5^T^WT' .N -N>r>A < x :>.-;: - 5 -; 

' - - - -> -

^.t \LT2 '-i \ x \7 ' - i \ \

l / 'xN^'^" , /^'V^^01 ^ 'Xl/Gun^on 'x ^ 

- - i%' - esereir x xTQ- - - ' ' ^ 1

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

/'-'>x-^r/^.10!

AREA EXCLUDED FROM STUDY

\ /

107C

25

I

1:2,000,000

50

I______

75

I

108°

100 MILES

I I I I 

25 50 75 100 KILOMETERS

UNIT-AVERAGED POROSITY

43°

/ II* x\

/ x I |X

:v

108"

St

k p?

^tenelle 

ruoir

I / O

Qo

o

/0.00022

B.oidi i i

NO 

DATA

^ 1,1

0.00001>

U1 mmerer

,r

I I 

I I

/0.03lJ I I "T 

I 

( I

I RodT\ > 

Rivtr

A ).021 &

J07°

-'

41° \ MU^OMING

nr

NO __ 

DATA /iiachesne

V<*

NO 

DATA

W-r;

/

106°

39°'

 "_ -s. \ v *rs v \ ^.^^ ~ -s

^^^;vV^-'^V\ 

/ js,; i/i^jvz^,'; rVi^i^ /A "V% - R^^r: -JSjj:,',-:'- I,

0.0086.

oa/ / ^X^^-'-~"''V- ^-'-'^- --|"'^ A/ ^^-i^ :' :: V-^' :: * : - r^ ^ ::

/7^ -T^Y /^' - ' : ;- 'V '*?- ' : ',~> /" ^' - 'f x/

^ /i /^;^'':::^W^: V-"T>- : v 

6 ^ />;^^^r:- : ;^;:v\^;V::.] ;^

ff ', - ^',:V^^^::^xl'V::-r h:

;^^;^^^>s^^^^^o

^Bl^; ;-'i:' ^l ip^v ^; xv, 'I:«v/-'-^

38°

0.00063

' ^vT'

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

urangd

Pagosa 

Springs,

NO

^ s~T,

x,-

Ferry

";v?J:,v:

^

;NI 

'-" ^ '/

v ShjpYick

37°

ICO

;, Reservoir

lington

i / > '

AREA EXCLUDED FROM STUDY

36°

'107°

-'36°

25

I

1:2,000,000

50

I____

75

I

108°

100 MILES

I 

25 50 75

I 

100 KILOMETERS

UNIT-AVERAGED HYDRAULIC CONDUCTIVITY

EXPLANATION

Area where the Park City-State Bridge zone is missing because of erosion 

or nondeposition

Unit-Averaged Porosity

-3 Line of equal estimated unit-averaged porosity Dashed where approximately 

located. Interval is 1 percent

3.6

Site at which unit-averaged porosity was estimated as the mean of 

laboratory determined values in a borehole interval representative of 

the entire Park City-State Bridge zone at the site Number shown is the 

mean porosity in the interval, in percent

Unit-Averaged Hydraulic Conductivity

Relative unit-averaged hydraulic conductivity

| I Moderate 

Small

-0.07 

0.015

0.021

Line of equal estimated unit-averaged hydraulic conductivity Dashed 

where approximately located. Interval, in feet per day, is variable

Limit of data

Data Sites Number shown is hydraulic conductivity, in feet per day

Site at which estimate was based on permeability determined by a drill-stem 

test

Site at which esitmate was based on the mean of laboratory-determined 

permeability values in a borehole interval

Base from U.S. Geological Survey 

U.S. base map, 1:2,500,000 UNIT-AVERAGED POROSITY AND HYDRAULIC CONDUCTIVITY OF THE PARK CITY-STATE BRIDGE ZONE OF THE CANYONLANDS AQUIFER IN THE UPPER COLORADO RIVER BASIN AND VICINITY

IN ARIZONA, COLORADO, UTAH, AND WYOMING !

By

Arthur L. Geldon ' 

2002
USGS U.S. DEPARTMENT OF THE INTERIOR

science for a changing world U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1411-B

Transmissivity of and maximum yields from the Park City-State Bridge zone PLATE 10

Geldon, A.L., 2002, Hydrologic properties and ground-water flow systems of the Paleozoic rocks in the Upper 

Colorado River Basin in Arizona, Colorado, New Mexico, Utah, and Wyoming, excluding the San Juan Basin

43'

42

AREA EXCLUDED FROM STUDY

110

Kendall Warm Spring 

Kendall Cold Spring

43'

42

 40°

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

107 C

25

I

1:2,000,000

50

I______

75

I

108°

100 MILES

 '^ig Gorge o 

 "> j ) Taylor Ranch 

rm Spring

ks£9§£a

^ ' , ,>/V ' 'v ' , ,\l'J > 'v ' ,1/1 W' l - '\ , I r, ' -^ ' , , I , V' , '^ ' , , I/ ', ', ^,

x ' -v^3 - - _' ^ ' "-A-- ' ' ^ ' r^-V- i ' ^ ' X^- - - ' "feHufidc ., -/- i / x ' 1 ,. \J_.. . ^ ]^K'/, -^~/^'/^~^~,'^'^' ^ -.'.'-'/, - ^ \ 's ?'?, - rr^- -*io7-

^>C' - - '- - i - ^i_^-^Q^ i - V ^- V- - ,-'--',, , -Silvferforr '< -J^-'

AREA EXCLUDED FROM STUDY

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

107°

25

I

1:2,000,000

50

I______

75

I

100 MILES

25 50

I I 

75 100 KILOMETERS 25 50 75

I 

100 KILOMETERS

COMPOSITE TRANSMISSIVITY MAXIMUM YIELDS

EXPLANATION

Area where the Park City-State Bridge zone is missing because of erosion 

or nondeposition

Composite Transmissivity

Relative composite transmissivity

Large

Moderate

Small

-10- Line of equal estimated composite transmissivity Location is approximate. 

Interval, in feet squared per day, is variable

Limit of data

Maximum Yields

Relative maximum yield

Large

Moderate

Small

 10- Line of equal yield from wells and springs under artesian conditions 

Location is approximate. Interval, in gallons per minute, is variable. Map is 

based on maximum measured, reported, or estimated values in boreholes or 

survey sections

Limit of data 

Data sites

Borehole Discharge during a drill-stem test, flow into a well during drilling, 

or flow from a well without drawdown after completion is indicated

Spring Large springs mentioned in the text are labeled

Base from U.S. Geological Survey 

U.S. base map, 1:2,500,000 COMPOSITE TRANSMISSIVITY OF AND MAXIMUM YIELDS FROM THE PARK CITY-STATE BRIDGE ZONE OF THE CANYONLANDS AQUIFER IN THE UPPER COLORADO RIVER BASIN AND VICINITY

IN ARIZONA, COLORADO, UTAH, AND WYOMING i

By

Arthur L. Geldon , 

2002
__ _ _ _ _ U.S. DEPARTMENT OF THE INTERIOR

science fora changing world U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1411-B

Potentiometric surfaces of the Madison and Canyonland aquifers PLATE 11

Geldon, A.L, 2002. Hydrologic properties and ground-water flow systems of the Paleozoic rocks in the Upper 

Colorado River Basin in Arizona, Colorado, New Mexico, Utah, and Wyoming, excluding the San Juan Basin

, Lake Ridge-^ 

Fogarty CreekDry Piney gas

I I I "» I'N^V*",

| \U\Voj ^

^} (

V^^rsi/- ~/ v

'07j5fStL\ A^-r-^f, /1' v

\ f,? I § /' ,U., 

A-jig /S L--'^)-'^ --\-~ \ x^-A^^u

5 ^X/V>V-\C/ /^iSrTsG 'K'

-

m-^f^ -3 \\ X- \ *<&,\, ^~^'^>'^',\'6>t

*\ ^ \v ''~- ~\ ' -,' ~ ^ ~ c& ' \

^^'^^fc^-^

^ AX\\V-_.} V^VTrV * x '<-ta

i I 4\>( p^f^ I i r//^K/ iw\*\ ' i /A<v Wvk /

Bowles Fish

Hatchery

Spring JunctToij '

:^v/f''^

NO DATA

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

Vaseys

Paradise

Spring

112

107°

25

I

1:2,000,000 

50

I____

75

I

100 MILES

J

I 

25 50

I 

75

I 

100 KILOMETERS

REDWALL-LEADVILLE ZONE OF MADISON AQUIFER

. Kendall 

Warm 

Spring

108°

s< -'Happy Springs

I . / n:i f.^i^

O'Brien Springs 

oil field

' ~ '~. 40°

^ /^ "^w: 7: -'- A-' - '^^1S?^1&^ H^ *^' ^Nc

) ' ))-y^''\ &*2L£ip \

'^r^tsafrttoalj-: \

,-.' ^ .SDrir^cal ' -. ' - 

>c^ r::V^

t W -J'-' -V-- ' 'V -

-n^ 0"^" r- r '

-,,-A. ^'J- -A38= 

- - - y - i_J- '-.'_/

risii^-rrr!

£^-Z->! \

EW MEXICO

Boundary

Butte

oilfield

-^-5,000 

EXPLANATION

Area where the Redwall-Leadville, Weber-De Chelly, or Cutler-Maroon 

zone is missing because of erosion or nondeposition

Potentiometric contour Shows altitude at which water level would have stood 

in tightly cased wells. Dashed where approximately located. Arrow indicates 

direction of ground-water movement assuming the aquifer is isotropic. 

Contour interval, in feet, is variable. National Geodetic Vertical Datum of 

1929. For the Weber-De Chelly and Cutler-Maroon aquifers, potentiometric 

contours south of latitude 37° are based in part on Cooley and others (1969, 

fig. 9); Levings and Farrar (1977a, 1977b, 1977c); and Eychaner (1983, 

fig. 3); potentiometric contours between Grand Junction and Glenwood 

Springs, Colorado, are based in part on topography

Limit of data

- Ground-water divide Dashed where approximately located

 B' Location of hydrogeologic section shown in figures 94 and 98

Eastern extent of Weber-De Chelly zone as a fully saturated, productive 

hydrogeologic unit East of this line the Weber-De Chelly zone pinches 

out and where present is partially saturated to unsaturated. The principal 

productive zone in the Canyonlands aquifer east of the line is the 

Cutler-Maroon zone. Heads shown west of the line are for the Weber-De 

Chelly zone. Heads shown east of the line are for the Cutler-Maroon zone. 

At the line heads in the Weber-De Chelly and Cutler-Maroon zones are 

equal, and heads for both zones are shown

Data sites

Borehole Static water level is plotted

Flowing well Altitude of land surface is plotted if static water level is not 

known

Spring Altitude of land surface is plotted. Springs with discharges of 

1,000 gallons per minute or more are plotted

Sink Altitude of land surface is plotted

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

1:2,000,000

25

___I

~~i r

25 50

50

I

75 100 MILES

i i 

75 100 KILOMETERS

WEBER-DE CHELLY AND CUTLER-MAROON ZONES OF CANYONLANDS AQUIFER

Base from U.S. Geological Survey 

U.S. base map, 1:2,500,000

POTENTIOMETRIC SURFACES OF THE MADISON AND CANYONLANDS AQUIFERS IN THE UPPER COLORADO RIVER BASIN AND VICINITY,

IN ARIZONA, COLORADO, NEW MEXICO, UTAH, AND WYOMING

By

Arthur L. Geldon 

2002
USGS U.S. DEPARTMENT OF THE INTERIOR

science for a changing world U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1411-B

Difference between potentiometric heads, Canyonlands and Madison aquifers PLATE 12

Geldon, A.L.. 2002. Hydrologic properties and ground-water flow systems of the Paleozoic rocks in the Upper 

Colorado River Basin in Arizona. Colorado. New Mexico. Utah, and Wyoming, excluding the San Juan Basin

43

42

WYOMING

OLORA"

_ - i x x ' Y L - ~ i ' ^

s ~ ~ //T - ^

^ l ^ ~ .^ \I' X \ N ~

AREA EXCLUDED FROM STUDY

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

\l

119°^^ 112

107°

25

1:2,000,000 

50 75

108°

100 MILES

I 1 I I 

25 50 75 100 KILOMETERS

EXPLANATION

Area where either the Canyonlands aquifer, Madison aquifer, or both 

aquifers are missing because of erosion, nondeposition, or faulting

Difference, in feet, between potentiometric heads in the Canyonlands 

aquifer and Four Corners aquifer system

3,500 to 4,500 

2,500 to 3,500 

1,500 to 2,500 

500 to 1,500

-500 to 500

-1,500 to-500

-2,500 to -1,500

-3,500 to -2,500

Limit of data

Base from U.S. Geological Survey 

U.S. base map, 1:2,500,000 DIFFERENCE BETWEEN POTENTIOMETRIC HEADS IN THE CANYONLANDS AQUIFER AND MADISON AQUIFER

IN THE UPPER COLORADO RIVER BASIN AND VICINITY IN ARIZONA, 

COLORADO, NEW MEXICO, UTAH, AND WYOMING

By

Arthur L. Geldon 

2002
__ USil W u-s- DEPARTMENT OF THE INTERIOR

science for a changing world U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1411-B

Linear velocity of water in the Redwall-Leadville and Weber-De Chelly zones PLATE 13

Geldon, A.L.. 2002. Hydrologic properties and ground-water flow systems of the Paleozoic rocks in the Upper 

Colorado River Basin in Arizona, Colorado, New Mexico, Utah, and Wyoming, excluding the San Juan Basin

110°

110°

43'

AREA EXCLUDED FROM STUDY

43°

' v i \

HP'\ ;A '«ajK \ . 106°JA

V'V"- t^^fx ^'V.'V-'-' 1 ^''^^

- \/- - HttSulphuASpririgs' ' >-^^ \ ./

X ^/ ^ x ^ ^^-4 -* ^^ ^ ^ 1

*S' <-,- 4 >4^-r77-^D v x ' ,-) 

~ '. ^N - x/TA" :,' - '--4

BOUNDARY OF

UPPER COLORADO

RIVER BASIN

AREA EXCLUDED FROM STUDY

EXPLANATION

Area where the Redwall-Leadville or Weber-De Chelly zone is missing 

or unsaturated

 0.001 Line of equal estimated average linear velocity Interval, in feet per day, 

is variable

 Limit of data

BOUNDARY OF 

UPPER COLORADO 

BASIN

25

1:2,000,000

50 75 100 MILES

25

I

1:2,000,000

50

I______

75

I

108°

100 MILES 

_I

25 50 75 100 KILOMETERS

25

i r i

50 75 100 KILOMETERS

REDWALL-LEADVILLE ZONE OF MADISON AQUIFER WEBER-DE CHELLY ZONE OF CANYONLANDS AQUIFER

Base from U.S. Geological Survey 

U.S. base map, 1:2,500,000

AVERAGE UNEAR VELOCITY OF WATER IN THE REDWALL-LEADVILLE ZONE OF THE MADISON AQUIFER AND WEBER-DE CHELLY ZONE OF THE CANYONLANDS AQUIFER

IN THE UPPER COLORADO RIVER BASIN IN ARIZONA, COLORADO, NEW MEXICO, UTAH, AND WYOMING

By

Arthur L. Geldon 

2002