Groundwater Flow in Part of the Little Missouri River Basin, North Dakota

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1970 Groundwater flow in part of the Little iM ssouri River Basin, North Dakota Thomas M. Hamilton University of North Dakota

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Recommended Citation Hamilton, Thomas M., "Groundwater flow in part of the Little iM ssouri River Basin, North Dakota" (1970). Theses and Dissertations. 121. https://commons.und.edu/theses/121

This Dissertation is brought to you for free and open access by the Theses, Dissertations, and Senior Projects at UND Scholarly Commons. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of UND Scholarly Commons. For more information, please contact [email protected]. GROUNDWATER FLOW IN PART OF THE LITTLE MISSOURI RIVER BASIN, NORTH DAKOTA

by Thomas M Hamilton B. s. in Geology, Capital University, 1965 M~ s. in Geology, University of North Dakota, 1967

A Dissertation Submitted to the Faculty of the University of North Dakota in partial.fulfillment of the requirements for the Degree of Doctor of Philosophy

Grand Forks, North Dakota

June 1970 f.. i I I l

This dissertation submitted by Thomas M Hamilton 1n partial fulfillment of the requirements for the Degree of Doctor of Philosophy from the University of North Dakota is here·by approved by the Faculty Advisory Comm1 ttee under whom the work has been done.

Chairman) ~~.-{__~~ #~~~-e jj:l ! ·~ II

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Dean of the Graduate School

310328 Permission

Title Groundwa. ter Flow· in Part of the ----...... _ ...... a.;..-=...... --= ...... ---- ...... ------

Little Missouri River Basin, North Dakota

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In presenting this dissertation in partial fulfillment of the requirements for a graduate degree from the University of North Dakota. I agree that the Library of ·this University shall make it .freely available for inspection. I further agree that permission for extensive copy ing for scholarly purposes may be granted by the professor who supervised my dissertation work or, in his absence, by the Chairman of the Department or the Dean of the Graduate School. It is under stood that any copying or publication or other use of this dissertation or part thereof for financial gain shall not be allowed without my written per mission. It is also understood that due recog nition shall 'be given to me and to the University of North Dakota in any scholarly use which may be made of any material in my dissertation.

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iii ACKNOWLEDGMENTS

I am grateful to many individuals and organizations for their assistance and support during the course of this study. All members of my committee. and particularly the chairman. Dr. Lee Clayton. are gratefully acknowledged for their many useful criticisms and suggestions during the course of this project. The other members of the committee are Drs. Walter Moore. Frank Karner. Edwin Noble. and Vera Facey. Mr. Quentin Paulson and Mr. Henry Trapp. Jr. of the U. s. Geological Survey, Bismarck. North Dakota are ac lcnowledged for their advice and for supplying some much needed basic data. Many other members of the u. s. Geol ogical Survey provided suggestions and services. I would like to thank the North Dakota State De partment of Health for allowing me access to their files of water analyses and for supplying copies of them. The National Park Service was most cooperative and allowed me access to normally restricted areas of the North and South Units of Theodore Roosevelt National Memorial Park. Mr. Harold Ziebarth of the Department of Geology. University of North Dakota spent many hours assisting me

iv ~-

with some phases of the labo~atory work. His efforts were greatly appreciated. The two persons who have supplied the most incentive for the completion of this project are my wife, Carolyn, and my son, Scott. My appreciation cannot be fully ex pressed. I am grateful to the u. s. Geological Survey, Water Resources Division for funding the first two years of this project. The collection and analysis of much of the data would not have been possible without this support. I am also grateful to the North Dakota Geological Survey, Dr. Edwin Noble, State Geologist, for field expense support during the summer of 1969. The University of North Dakota Computer Center donated many hours of machine ..time for data analysis •

V TABLE OF CONTENTS Page

ACKNOW'LEDGNENTS • • • • • • • • • • • • • • • • • • iv LIST OF TABLES •• • • . . . . . • • • • • • • • • • • i.x LIST OF ILLUSTRATIONS. • • • • • • • • • • • • • • • X

ABSTRACT •••• • • • • • • • • • • • • • • • • • • • xiii

INTRODUCTION. • • • • • • • • • • • • • • • • . . . • 1 Purpose • • • • • • • • • • • • • • • • • • • • 2 General Setting and Climate ••••••••• • 3 Terminology and Concepts ••••••.••••• • 3 Terms and concepts pertaining to the flow system •••••••••• • 3 Terms and concepts pertaining to the water chemistry •••••••• • 8 Previous and Present Studies ••••••••• • 9 Evaluation of Recent Work •••••••••• • 10 General theoretical background of groundwater flow ••••••••• • 10 Application and expansion of flow theory ••••••••••••• • 13 The Prairie Profile ••••••• • 1L1- Small-basin flow system ••••• • 17 Discussion and comparison of the models • • • • • • • • • • 17 Groundwater chemistry •••• • • • • • • 20 An Approach to Defining the Little Missouri River Flow System •• • • • • • • • • 22 • 24 OBSERVATIONS. • • • • • • • • • • • • • • • • • • • 24 Topography and Stratigraphy• • • • • • • • • • • • • • • 24 Topograph Y. • • • • • • • • • • • 26 Stratigraphy. • • • • • • • • • • • • • • 29 · Pierre Shale• • • • • • • • • • • • 32 Fox Hills Formation• • • • • • • 32 Hell Creek Formation. • • • • • • • Tullock, Ludlow, and • 33 Cannonl>all Formations• • • •• 33 ~ongue Biver Formation. • • • • • • TABLE OF CONTENTS Page

ACKNOl>JLEDGNENTS • • • • • • • • • • • • • • • • • • • iv LIST OF TABLES. • • • • • • • • • • • • • • • • • • • ix LIST OF ILLUSTRATIONS • • • • • • • • • • • • • • • • X ABSTRACT. • • • • • • • • • • • • • • • • • • • • • • Xiii INTRODUCTION. • • • • • • • • • • • • • • • • • • • • 1 Purpose • • . • • • • • • • • • • • • • • • • • 2 General Setting and Climate • • • • • • • • • • 3 Terminology and Concepts. • . • • • s • • • • • • 3 Terms and concepts pertaining to the flow system. • • • • • • • • • • 3 Terms and concepts pertaining to the water chemistry. • • • • • • • • 8 Previous and Present Studies. • • • • • • • • • 9 Evaluation of Recent Work • • • • • • • • • • • 10 General theoretical background of groundwater flow • • • • • • • • • • 10 Application and expansion of flow theory • • • • • • • • • • • • • • 13 The Prairie Profile • • • • • • • • 1Li, Small-basin flow system • • • • • • 17 Discussion and comparison of the models • • • • • • • • • • 17 Groundwater chemistry • • • • • • • • • • 20 An Approach to Defining the Little Missouri River Flow System. • • • • • • • • • 22

OBSERVATIONS. • • • • • • • • • • • • • • • • • • • • 24 Topography and Stratigraphy • • • • • • • • • • 24 Topography. • • • • • • • • • • • • • • • 24 Stratigraphy. . . • • • • • • • • • • • • 26 Pierre Shale. • • • • • • • • • • • 29 Fox Hills Formation • • • . • • • • J2 Hell Creek Formation. • • • • • • • 32 Tullock, Ludlow, and Cannonball Formations • • • • • • JJ Tongue River Formation. • • • • .. • 33

vi Page

Sentinel Butte Formation. • • • • • 34 Summary of the bedrock stratigraphy •••••• • • • • • 35 River alluViU,u •••••• • • • • • 35 Structure contour map on the Pierre Shale •••• • • • • • 38 Hydroge ology. • • • • • • • • • • • • • • • • • 43 Shallow groundwater •••••• • • • • • 43 Deep groundwater •••••••• ...... 46

FLOW-SYSTEM EVALUATION •••••• • • • • • • • • • • 51 Potential Distribution ••••••••••••• 51 The regional flow pattern •••••••• 58 The total flow vector ••••••• 61 Groundwater Chemistry ••••••••••••• 62 Deep groundwater chemistry •••••••• 63 Water from the Fox Hills Formation ••••••• • • • • • 63 Water from the Hell Creek Formation ••••••• • • • • • 75 Water from the Cannonball Formation •••••••••••• 84 Water samples from the Ludlow and Tongue River Formations ••• 91 Samples from springs •••••••• 91 Calcium-magnesium facies •••••• 94 Summary of the groundwater chemical flow system ••••••• 99 Chemistry of shallow groundwater~ •••• 102 Seepage Contributions to the Valley Fill Sediment •••••••••••••••• 115 Seepage from the stream channel at high stage • • • • • • • • • • • • • 115 Infiltration through ephemeral stream channels •••••••••••• 116 Seepage contributions from deep groundwater •••••••••••• 120 Possible relative orders.of magnitude ••••••••••••••• 121

CONCLUSIONS...... • • • • • • • • • . . • 123

Summary of Conclusions ••••••• • • • • • • 123 Usefulness of Present Groundwater Flow-System Models •••••••• ~ . . . . • 125

APPENDICES ••••• • • • • • • • • . . • • • • • • • 126 Appendix A: METHODS OF DATA COLLECTION AND A.i.'\J'ALYSIS. • • • • • • • • • • • • • • • • 127

vii Page

~·Ia ter Level Neasurements. • • • • • • • • 127 Collection of Water Samples ••••••• 130 .4..nalysis of Water Samples • • • • • • • • 132 Elevation Determinations ••••••••• 139 Location Format ••••••••••••• 140 Appendix B: SAMPLE LOGS •••••••••••• 143 Appendix C: ELEVATION OF THE PIERRE SHALE ••• 156

REFERENCES CITED. • • • • • • • • • • • • • • • • • • 175

viii LIST OF TABLES Table Page 1. Values of gradient in the discharge area with respect to the flow components •• • • 57 2. Variation in ppm total hardness (ca++ and Mg+~ as CaC03) with depth of 169 water samples from the recharge areas •••• • • 96

ix LIST OF ILLUSTRATIONS Figure Page 1. Location map of the part of North Dakota considered 1n this study ••••••• • • • 2. The vertical (V), lateral (La), and longitudinal (L) components of groundwater flow. • • • • • • • • • • • • • • • • 6 J. The horizontal component (H), the flow resultant (R), and· the total flow vector (T) of groundwater flow. • • • • • • • • • 7

4. The Prairie Profile ••• • • • • • • • • • • • 16 5. Small-basin flow systems determined by a mathematical model ••••••••••••• 19 6 .. General view of the badlands bordering the Little Missouri River, North Dakota •• • • 25 General view of isolated buttes on the regional eastward-sloping surface •• • • • 27 8. Generalized map showing the approximate boundary of the Williston basin and some major structural trends within the 'basin. • 28

9. Geologic map of the study area •••• • • • • Jl 10. Subsurface cross section in the center of the study area ••••••••• • • • • 37 11. Location of oil wells used in constructing a structure contour map •••••••• • • 40 12. Structure contour map on top of the Pierre Shale •••••••••••• • • • • 42 \ 13. Location map of' deep-groundwater wells f'rom which data was obtained •••• • • • • 48 14. Relationship of well depth and static water level •••••••••••• • • • • 49

x. Figure Page 15. Pattern of groundwater flow in the Little Ivlissouri valley, North Dakota ••••• • • 52 16. Pattern of groundwater flow in the Little Missouri valley, North Dakota ••••• • • 54 17. Pattern of groundwater flow in the Little Hissouri valley, North Dalwta. • • • • • • 56 18. Pattern of regional groundwater flow ••• • • 60 19. Sodium in relation to total cations in water samples from the discharge area. • • • • • 64 20. Chemical analysis diagram of groundwater from the Fox Hills Formation ••••• • • 21. Map showing the variation of the sulfate bicarbonate ratio in groundwater from the Fox Hills Formation•••••••• • • 68 22. Map showing the variation of fluoride in ppm in groundwater from the Fox Hills Formation. • • • • • • • • • • • • • • • • 70 23. Map showing the variation of chloride in ppm in groundwater from the Fox Hills Formation. • • • • • • • • • • • • • • • • 72 24. Map showing the variation of total dis solved solids in epm in groundwater from the Fox Hills Formation •••• • • • 74 25. Chemical analysis diagram of groundwater from the Hell Creek Formation ••••• • • 76 26. Map showing the variation of the sulfate bicarbonate ratio in groundwater from the Hell Creek Formation • • • • • • • .. • • • 78 27. Map showing the variation of chloride in ppm in groundwater from the Hell Creek Formation. • • • • • • • • • • • • • • • • Bo 28. Map showing the variation of the total dis solved solids in epm in groundwater from the Hell Creek Formation ••••••••• 8J 29. Chemical analysis diagram of groundwater from the Cannonball Formation ••••• • • 85

Xi ~!

11 1,, Figure Page 30. Map showing the variation of total dis solved solids in epm in groundwater from the Cannonball Formation ••••• • • 87 31. Chemical analysis diagram of groundwater from the Ludlow Formation ••••••• • • 92 32. Chemical analysis diagram of groundwater from the Tongue River Formation •••• • • 93 33. Chemical analysis diagram of groundwater from springs ••••••••••••• • • 95 34. Bicarbonate as a function of sulfate in groundwater samples from the discharge area ••••••••••••••••••• 100 35. Cross section showi11.E.; the general regional vertical variation in cation facies •••• 103 36. Cross section showing the general regional vertical variation in anion facies •••• 104 37. Generalized cross section showing the south to north variation of anion facies in the discharge area ••• • • • • 105 38. Water chemistry of two shallow groundwater samples indicating dilution resulting from seepage from the Little Missouri River ••••••••••••••••• • • 106 39. Chemical analysis diagram of shallow groundwater •••••••••••• • • • • 108 4o. Chemical analysis diagram of surface water samples ••••••••••• • • • • 110 41. Relationship of measured to calculated pH for some shallow groundwater samples •• 112 42. Relationship of measured to calculated pH for some surface-water samples. • • • • 113 43. Cumulative infiltration as a function of' time. • • • • • • • • • • • • • • • • • 118 44. Schematic diagram of the packer-gauge assembly used to measure the water pressure of flowing wells ••••• • • • • 129 45. Diagram illustrating the location format. . . 142 ABSTRACT

The Little Nissouri valley in western North Dakota is deeply incised into slightly permeable i"Iesozoic and Cenozoic sediments. An evaluation of the groundwater flow in part of this valley was 'based on the present groundwater flow-system models. Abrupt changes in the hydrochemical facies have been explained relative to a continuous flow system. The Little Missouri valley ls the discharge area of a regional groundwater flow system; it affects the po tential distribution of the flow system for a minimum of 1.000 feet below the valley floor. The discharge area is approximately the same width as the valley floor and has a ratio of the vertical to longitudinal flow component (in terms of' gradient) of at least 100. The groundwater divides in the center of the study area are asymmetrically spaced relative to the discharge area and underlie the surface-water divides. The recharge area to the west of the valley has a higher potential and steeper gradient than the eastern recharge area as a result of its higher elevation and overall lower per meability.

Xiii Lithology strongly controls the groundwater chemistry. The highest concentrations of dissolved solids are asso ciated with some of the shortest groundwater flow paths; this water usually contains abundant sulfate. Sodium is the dominant cation (comprising 90 to 99 percent of the total cations) in the discharge area and. below a depth of about 200 feet in the recharge areas. This sodium facies is the result of the exchange of sodium for calcium by cation exchange minerals in the sediment. Groundwater rich in calcium and magnesium occurs where much of the calcium and magnesium exchange capacity of the sediment has probably been exhausted .• Repeating anion facies occur in a vertical section of the flow system. Bicarbonate facies, occurring at depths of several hundred feet are attributable to a sequence of reactions initiated by the reduction of sulfate. The total change of the groundwater chemistry as a result of

this reduction is (1) a decrease in the absolute amount

of sulfate , ( 2) an increase in the amount of blear bona te •.

(J) an indirect increase in sodium, and (4) an increase in the total dissolved solids. The highly-permeable valley-fill sediment receives seepage contributions related to three sep~rate sources. The probable order of relative importance of these con tributions is (1) seepage from the regional groundwater flow system, (2) seepage through the beds of ephemeral

xiv streams during runoff, and (J) seepage through the river banks at high stream stage. Huch of the groundwater in the valley-fill sediment probably leaves the basin as underflow. The cations in the groundwater of the valley-fill sediment are composed of as much as 50 percent calcium and magnesium. This high percentage may be explained as a reversal of the cation-exchange equilibrium when calcium rich clays, that were eroded from the recharge areas, are brought into contact with the sodium-rich groundwater of the regional discharge area. INTRODUCTION

Most appra1sals of the quant1ty and ava1lab111ty of groundwater are presently d1rected toward the short- term econom1cs of 1ts w1thdrawal and cons1der a ground water system only 1n terms of d1screte aqu1fers. Water contr1buted from other parts of the system 1s often con

s1dered 1n such terms as 11 lealcage 11 , which if taken 11 ter ally, imply the existence of a defect or abnormality in

the system. This water is 11 a.bnormal 11 only as a result of assumptions and 11m1tat1ons placed on the system for purposes of evaluatio.n. The permeable uni ts of a ground water flow system may be the least 1mportant or only of proport1onally equal importance 1n many types of studies. The 1mportance of evaluating groundwater in terms of quantity, qual1ty, and flow-rate and d1rection of movement is not confined to hydrological studies. Pollution stud1es of the movement of contaminants, geological studies of d1agenes1s, botanical studies of certa1n plant commun1t1es, and engineering evaluations of slope stability are affected by one or more aspects of groundwater. The necessity of considering all aspects of groundwater in terms of a con t1nuous system is obvious.

l 2 The microscopic (1ntergranular) aspects of groundwater flow under natural conditions cannot ·be described at present because there is no means of describing the in finitesimal nature of the medium through which it moves. However, boundary-valued models that describe the large scale movement and chemistry of groundwater in terms of continuous flow systems have been proposed. The general applicability of existing models has been demonstrated for areas ranging in size from thousands of square miles (Maxey, 1968; Hitchon, 1969a·and 1969b) to a few square miles or less (Heyboom, 1967a; Williams, 1968). The models are constantly being improved. Testing is essential on all scales and under varying conditions of climate, geology, and topography in evaluation of their total usefulness (or uselessness) in groundwater studies.

Purpose

The purpose of this report is to present a preliminary evaluation of the groundwater flow system of part of the Little Missouri River basin in western North Dakota. Spe cific considerations include (1) the lateral extent of the regional discharge area, (2) the minimum depth effects of the river valley on the flow system, (3) the distribution and possible controls of groundwater-chemical facies, and {4) a first order approximation of the importance of sep arable sources of groundwater seepage to the valley fill J sediment.

General Setting and Climate

The study area is located in part of the Little Missouri River basin in western North Dakota (fig. 1). The area is sparsely populated; for example, Billings County has a population density of about one person per square mile, and much of the area is not easily accessible. The climate of the study area is typical of most of the semiarid Great Plains. The average annual rainfall is 14 to 15 inches; extreme variation from this average occurs locally. Most of the precipitation falls during thunderstorms of short duration and high intensity between April a.nd September. The mean potential evaporation is about J to 4 times the mean annual precipitation. The temperature averages about 40 to 42 degrees Fahreheit.

Terminology and Concepts

The purpose of this section is to define terms and concepts which are used in this report and not specifically described elsewhere. Terms and concepts pertaining to the flow system A flow system as defined by T6th (196J, p. 4806) is ••• a set of flow lines in which any two flow lines adjacent at one point of ,. the flow region 4

Figure 1.--Location map of the pa.rt of North Dakota considered in this study. The North and South Units of Theodore Roosevelt National Memorial Park are outlined.

--...... ------'----- 5

_ _j T, ll./8i

N. !-I-+---+--+--t--,.-l-fll.-r.'-~~..J..-.....;;.;..ir-,,l-...-1--..:::\

NORTH T DAKOTA 14'i

N ,...i-+--+---~~+.--1---4--4---+~0:.;::i.:.:N:..:..N=--i

II cJ NATIONAL PARK BOUNDARY . I _ __,_ __ - _j -

STARK T; 138: Ni-;+--+--+-----11;:-::;,.-,I---+---+--+---+---{

Ti 13'j N.1 ;---- ' SLOPE 6 remain adjacent through the whole region; they can be intersected anywhere by an uninterrupted surface across which flow takes place 1n one direction. Three types of flow systems are recognized, depending on the relationship to topography and t~e flow path lengths involved. {1) A local flow s;z:stem 1s developed between an adjacent topographic high and low and has flow path lengths ranging from a few feet to a few thousand feet. (2) An intermediate flow system is developed between inter mediate topographic highs and lows in the basin and gen erally has flow path lengths ranging from a few to several thousand feet. {J) A regional flow system is developed between the highest and lowest regionally significant topographic features in a 'basin and generally has flow path lengths measured in miles. Groundwater flow is three-dimensional and can be resolved into components and resultants. The components · (fig. 2) are the longitudinal component which is parallel to a river or divide, the vertical component (either up or down), and the lateral component which is normal to the ,,----- /I Ji // I I I /______I ; I I 1___ 1r-, I V I ' -~La----~11' Figure 2.--The vertical {V), lateral (La), and longitudinal (L) components of groundwater flow. 7 plane of the longitudinal and vertical components (parallel to the direction of maximum basin slope). These three components can be resolved into a flow resultant, a horizontal component and a total flow vector (Meyboom, van Everdingen, and Freeze, 1966) as shown in figure 3.

Figure 3.--The horizontal component (H), the flow resultant (R), and the total flow vector (T) of groundwater flow. The horizontal flow component is approximated by maps of the piezometric surface or water table and the flow resultant is approximated by cross sections of the flow field. A flow-system cross section is constructed by con touring values of potential in the plane of the section and by drawing flow resultants at right angles to the equipotential lines (for homogeneous isotropic conditions).

An equipotential line can only be terminated at right angles on an impermeable boundary of the flow field. Most cross sections representing field conditions must be constructed with a consideration of anisotropic conditions in the sed iment and vertical exaggeration of the section. Under these conditions, (1) equipotential lines and flow resultants 8 are refracted at a permeability interface according to the tangent law (Hubbert, 19Lr,o, p. 943), and (2) flow resul tants constructed on a vertically exaggerated section can no longer be drawn normal to equipotential lines but must be corrected for the distortion (van Everdingen, 1963). A recharge area is an area in which the groundwater

potential decreases with dep·th. A discharge area is one in which the potential increases with depth. The direction of potential change at depth may, in some cases, be re versed if the boundary between two flow systems is exceeded.

The water table is defined as a,. surface of a flow system at atmospheric pressure. Terms and concepts pertaining to the water chemistry The concentration of chemical constituents in water may be expressed in various ways. Two units for expressing concentration are used in this report. They are (1) parts per million(ppm), which expresses the parts by weight of

dissolved matter in a million parts by weight of solution and (2) equivalents per million (epm), which is the normality X 103 • A hYdrochemical tacies is a lateral or vertical sub- division ot a bOdy of water Which is distinguishable from other parts ot th e same system on the basis of its ~- character. mh C"CmJ.Cal le Classification that 1s use various facies foll d to designate ows that or Back (1960) in terms ot the 'and 1s 8%J>ressed Percentage (based Oll equJ.Yl&lents ]JeJ: •f,, ....Jon) 8 are refracted at a permeability interface according to the tangent law (HU:hbert, 1940, p. 94.3), and (2) flow resul tants constructed on a vertically exaggerated section can no longer 'be drawn normal to equipotential lines but must be corrected for the distortion (van Everdi:ngen, 196.3). A rechar~e area is an area in which the groundwater

potential decreases with dep·th. A discharge area is one in which the potential increases with depth. The direction of potential change at depth may, in some cases, 'be re versed if the boundary between two flow systems is exceeded.

The water t:ible is defined as a.,. surface of a flow system at atmospheric pressure. Terms and concepts pertaining to the water chemistry The concentration of chemical constituents in water may be expressed in various ways. ·Two units for expressing concentration are used in this report. They are (1) parts per million(npm), which expresses the parts by weight of dissolved matter in a million parts by weight of solution a~d (2) equivalents per million (epm), which is the normality X 103. A hydrochemical facies is a lateral or vertical sub division of a 'body of water which is distinguishable from other parts of the same system-on the basis of its chemical character. The classification that is used to designate various facies follows that of Back (1960), and is expressed in terms of the percentage (based on equivalents per million) 9 of cations, anions, or both. A facies term which stands alone (either cation.or anion or a combination) indicates that the ion content of the water is composed of at least 90 percent of that member (for example, bicarbonate water indicates that the anions are composed of at least 90 percent bicarbonate). Double anion terms (for example 'bicarbonate-sulfate) describe water that is composed of at least 50 percent ·but less than 90 percent of the first named member {bicarbonate); the second member is greater than 10 but less than 50 percent of the total anions. A calcium-magnesium fac1es indicates that the cations are composed of at least 90 percent calcium and magnesium. But, a calcium-sodium facies represents water in which the calcium and magnesium comprise at least 50 percent of the total cations. These few examples represent the general scheme of the class ification.

Previous and ~resent Studies

No formal studies of the groundwater movement in the study area had been made prior to 1967, but reference to the occurrence and general chemical character of the . groundwater was included in reports of regional and state wide surveys {Riffenburg, 1925; Simpson, 1929; Abbott and Voedisch, 1938; North Dakota State Dept. of Health, 1964). Tables of well schedules for individual counties were 10 compiled during the 1930's as a part of a project of the ~'larks Progress Administration. Data :from a few, shallow observation wells in the area are included in various u. s. Geological Survey reports. At the present time the u. s. Geological Survey is completing a groundwater resource evaluation of Stark and Hettinger Counties, which adjoin and partially overlap the eastern side of the study area.

Evaluation of Recent Work

Ger.eral theoretical background of groundwater flow The movement of groundwater has long been known to proceed in the direction of decreasing head, and this concept formed the basis for depicting and interpreting directions of movement of groundwater by constructing p1ezometric maps. No satisfactory mathematical expression of this condition·was available until Hubbert's (1940) work in which he described the energy potential (f) at any point in the system in terms of the measurable physical properties of the system. This relationship, for general three dimensional flow, was expressed as a generalization of the Bernoulli equation in the form

p 2 ~ = gZ + ( dP + V , (1) JPo e 2 where g is the acceleration due to gravity, Z is the height above a datum, P is pressure, e is the density of the 11 fluid, and Vis the velocity of the fluid. The elements of the equation can be considered as potential energy 2 (gZ), flow energy (~), and kinetic energy(~). If the density is constant or if its functional relationship to Pis lmown, then integration yields a constant, provided four conditions hold: (1) flow is along a streamline,

(2) the fluid is incompressible, (J) the fluid is friction less, and (4) the system is in a steady state. Condition

(J) holds only for ideal fluid flow; therefore, the re lationship would not be constant on a given groundwater flow line but would decrease in the direction of flow. The expression of kinetic energy can be eliminated from the equation in its application to groundwater flow 'because of the extremely low velocities involved, reducing the equation to the form

= gZ + iP g• (2) ~ '1?o e

Integration yields

P-Po g Z + -, {J) e which can be further simplified (Hubbert, 1940, p. 802) to

~ = gh, (4) where his elevation to which water rises in a piezometer inserted to some point in the system. The result in this form is energy per unit mass with dimensions, in terms of length (L), time (T), and mass (M), of (L/T) 2 • A different 12 form of this expression can be derived ·by dividing equation

4 by gravity (g) to yield P-P ~ = Z + )t O = h, (5) where ~ is the specific weight (~g). The potential in this :rorm can be interpreted as energy per unit weight (ft-lb/lb). The dimensions are

This form is convenient because the measurement or~ in terms of h can be made from the free surface in a piezometer and reported as feet of water. The magnitude of~ in this form is generally referred to as the piezometric or total head. Another important concept in evaluating a flow system is the relationship expressed by Darcy's law. A general form for this law is given as

V = -K g,h (6) dl' where Vis velocity of flow, dh/dl is the·differential change of head (h) with length of flow (1) and is referred to as the hydraulic gradient, and K is a proportionality constant (hydraulic conductivity). The negative sign indicates that flow is in the direction of decreasing potential.. !t.uch recent research has been devoted to the validity of Darcy's law as it is related to both rate of :flow and the intergranular forces of fine-grained sediment 13 (non-Darcy flow). Meyboom (1966a) summarizes the literature in a general discussion of these concepts. These aspects are not considered here. Application and expansion of flow theory Following the publication of Hubbert•s paper, little work was done with the application of basic flow theory to stratified media on a large scale. Much research was de voted to developing and improving pump-test theory in search of a means for evaluating the permeability (hydraulic conductivity) of aquifers. A general model (one which uses botanic, geologic, pedologic, and hydrologic conditions) for predicting basin-wide and inter'basin groundwater flow was not developed until the early 1960 1 s. Meinzer (1927) had earlier described the occurrence of phreatophytes and the usefulness of such observations in groundwater studies. Neyboom (196:3) described the groundwater flow conditions in the semiarid prairie of Saskatchewan, Canada. The re sulting model, based on field observations, was referred ; to as the Prairie Profile. At about the same time Toth . ' (196:3) presented a theoretical treatment of groundwater flow in small basins. The conclusions obtained from these two approaches will be compared later. The concept of qualitative and quantitative applications in the form of digital modeling of regional groundwater flow systems was treated by Freeze and Witherspoon (1966, 1967, and 1968). They presented mathematical models (1966) for nonhomogeneous anisotropic conditions that have steady state solutions 14 obtainable by digital computer. These models were tested under varying conditions of water ta'ble and permeability configuration (1967) and resulted in several conclusions pertaining to the properties of regional flow systems. Two of those conclusions are of particular interest: (1) recharge areas are consistently larger than discharge areas (p. 623) and (2) discontinuites in permeability associated with stratigraphic pinchouts can create unanti cipated recharge and discharge areas (p. 634). The third of this series of papers (1968) considered quantitative evaluation of theoretical flow nets and their comparison with field examples. Hitchon {1969a and 1969b) applied concepts of fluid flow in an analysis of the effects of geology and topog raphy on fluid migration in a large sedimentary basin. He concluded that the effect of large river valleys on fluid potential distributions was observable to depths of at least 5,000 ft (1969a, p. 193), and that the flow system was affected significantly by high permeability zones at depth, even if they were not of basin-wide extent (1969b, p. 468). The Prairie Profile.-Meyboom (1963) combined the observations of several workers with his own and presented a model which he felt made mapping of the flow system possible using information from many scientific disciplines. He felt that this model was particularly well suited to conditions in western Canada, hence the name Prairie 15 Profile. The flow conditions of the model were established on the basis of topography and geology (p. 9). By definition the Prairie Profile consists of a central topographic high bounde& at either side by an area. of lower elevation. Geolog ically the profile is made up of two layers of dif.ferent permeability, the upper layer having the lower permeability. Through the profile is a steady flow of groundwater from the area of recharge to the area of discharge. The ratio of permeabilities is such that groundwater flow is essentially downward through the material of low permeability and lateral and upward through the underlying more permeable layer. The potential distribution in the profile is governed by the differential equation of Laplace. The model (fig. 4) depicts a large-scale flow system bounded by topographically significant lows on which is superimposed local flow systems. The Prairie Profile differs from the classical model of an artesian system in that it does not require outcrop of the aquifer updip from the artesian area and it does not limit recharge to the outcrop area, thereby, greatly increasing the area of recharge. The model also presents the possibility that in a local flow system one could drill a well that shows an increase in head with depth followed by a decrease with depth when the basal limit of the local system has been exceeded. The recharge area may contain fresh-water phreat ophytes. The discharge areas of the model are charac terized by accumulations of sodium salts, alkali soils, and vegetation that is both alkali tolerant and phreat ophytic. ---

· · pla1a's a,.:! n'.,~~ sr,:1;: dee~- --App,oximate bounda1ies of1echarie area of deep layer-~ \1)is,chart!and shal'.011 area: r.o~;ni sa::ne ·~ell\ m,:\s.

P,ecipitation Discharge aiea in sidehill valley: 300 l~~i·---I I I I """"'l """''. \ "'"' ""'" •"' J,reaolda,;>llaA:r,,r;:\::;-}r"""' . - t I I '" feet Area of dee;>_ 1000 ")'(- -IIOt,ing V, ell$ eoo ""'"'"'"''""''"'""' I . I ' ~-'-'..L.----_, ------i------t---\-- __v' / / / &>>""'·""'". . '"''" I-" 600 '<~ .J,. 'f...._ I ---:} k',.,/-\ >{ -1.. • ""' °' ,!,00mr•;-.1'\:l,,''f'• i:'"~SL~:C~~~·:!!/!!~!-'!3!!;;:~~~.Jc:i·,:::.,.,,,,,;·.'·.. ,.~ .. ~7'""~.-.~~·-~ . ·"'"""-~-~~·C'::;.:.,:·';',~--~r-$0 .. ,.. ,.. ...-.-:,.,.•.:: :·,..-.•: ·:: .-:c~-::,,

p;,r:;ri:>n of ft.:,,v ill de•;> 1,,., .. .. _a!Jlao, -· Direction of no-''· • •••••.•••••' - Lht cf n11.:1J he.:1d • ••••••••• - -

Figure 4,--The Pra1r1e Profne, from Meyboom (1966, P• 2?), 17 Small-basin flow system.-Toth (1963) developed a mathematical model for groundwater flow with specified boundary conditions starting with Hubbert's (1940) equation for potential distribution. The model is for small basins (upper limit of several hundred square miles, p. 4797) U..'1.derlain by isotropic homogeneous material and bounded by symmetrical divides. The water table was represented as a horizontal surface under assumed sinusoidal topography. The half width of the theoretical basin was taken to be 20,000 feet, and values for depth to the horizontal imper meable boundary ranged from 1,000 to 10,000 feet. Inspection of flow systems derived from this model (fig. 5) indicates the existence of three different mag nitudes of groundwater flow systems, (1) local, (2) inter mediate, and (3) regional. Discussion and comparison of the models.-The models are different in approach, one theoretical and one prac tical. The situation they depict is in all major aspects the same. The applicability of some assumptions in T6th 1 s model, particularly homogeneous isotropic conditions, and to some extent symmetrical drainage divides, may not seem consistent with actual conditions. But T6th states (p. 4811) ••• in drainage basins, do~m to depths at which basin-wide extended layers of' con trasting low permeability are found, ground water motion may be treated as an uncon fined flow through a homogeneous medium. This neglects, by de:f'inition. stratigraphic discontinuities 18

Figure 5.--Small-basin flow systems determined by a mathematical model, from Toth (1963, p. 480?). 19

., ;;.

() .,E

.. ,, ::. ·;,.. 0 .. - -:; -~,,, r} . I • I i I I D · I ..

~... g0 o. (\J "..

D. t

0 V " -V ..' "t~.. o; . . M. 20 which might cause significant chanee in the flow system (Freeze and Witherspoon, 1967). Toth," however, considered this condition theoretically in an earlier paper (1962). Variation from the assumed conditions could be expected to occur, ·but can ·be handled mathematically by determination of the proper functional relationship; it does increase the complexity of the analysis. Apparently the major point of disagreement between the two authors is the scale to which a flow system can , develop. Toth maintains that no large scale systems (several tens of miles) can be established in any area except one having a gentle continuous slope and no locai relief (p. 4808). Meyboom notes (196J, p. 27) field evidence indicating that large scale systems are possible, even in areas of significant local relief. Groundwater chemistr:'{ Groundwater chemistry has important practical aspects, particularly in terms of its quality for consumption and irrigation and as it is used in oil exploration. Some chemical constituents have been used in studies of ground water occurrence. For example, bromide concentrations have been used to differentiate salinity sources (l?iper, Garrett, and others, 1953). The first extensive treatment of changes in water chemistry with respect to position and time was given by Chebotarev {1955). His data was from several thousand water samples which ranged in composition from brine to 21 fresh. Based on an analysis of this data he proposed the following g:-oui1.dwa.ter chemical sequence and stated:

Because: of the differi::mt mobility of the chemical elenents and the nature of the physical-che~ical processes in the sub surface reservoir, the geochemical types of water change with the increase of the total salinity as well as with increas in,g depth, and the following series hold good:

Simply stated. the sequence means that the most soluble products remain in solution, or the greater the length of time that watar has been in contact with the sediment, the greater the concentration of chloride and total dis solved solids. Water chemistry reflects residence in the sediment and should therefore be a qualitative tool in studies of direction of groundwater flow. Brown (1963) elaborated on this concept. Others have employed it as either a primary ~eans of evaluating direction of flow (Charron. 1965; Back, 1960) or as a secondary indicator (Meyboom 1966b; T6th, 1968). Va:i::·iations of Chebotarev•s sequence have been cited in studies of groundwater flow systems, but deviation is usually explained as occurring 1n a system of insufficient magnitude to produce the complete sequence, or as a result of 11 unusua.1n lithologic effects. 22

.An Approach to Defining the Little 1'1issouri River Flow System

A general model of the Little Missouri River flow system was conceived early in the study to serve as a guide for data collection. The valley bottom was assumed to be a discharge area because of its low topographic position and because the stream flows during most extended dry periods. Evidence supporting the existence of a discharge area in the Little Missouri valley is the pres ence of phreatophytes (Meinzer, 192?) on the valley floor, the presence of springs and seeps, and localized accumu

; lations of alkali salts along the base of the valley wall I l' ! (Eeyboom. 1966b). The most common phreatophyte is PoPulus sargentii (plains cottonwood), which in a semi arid environment is a definite phreatophyte (Mey'boom, 1967, p. 32). The valley-bottom soils are not good flow-system indicators because they are immature as a result of much recent alluviation (Hamilton, 1967; Everitt, 1968). The valley is a groundwater discharge area; however, the magnitude of the flow system (the vertical and lateral extent) could not be determined without examining the physical and chemical properties of the system. Most of the data came from the discharge end of the regional flow system because the majority of wells tapping this system are located there. Very few deep wells exist 2.3 outside the valley. The private wells drilled in the uplands are shallow and most are probably related to the discli.a.rge ends of locally controlled groundwater flow systems. The local groundwater systems are an important part of the total system but they could not 'be individually evaluated on the scale of this study. A few deep municipal wells do exist in the recharge area and they furnished the few data points at the end of the system. It was necessary to locate groups of wells that would yield accurate data (See appendix A) and would 'be aligned at nearly right angles to the valley axis so they could be used to construct flow-system cross sections. Although deep wells have been drilled in the Little Missouri River valley for many years the area is not highly developed, and it was difficult to find closely spaced wells penetrating to similar depths in some areas. ~.any of the older wells are of unknown depth and in some instances the casings are badly corroded. No measurements or samples were collected from the latter wells. OBSERVATIONS

Topography and Stratigraphy

The establishment and maintenance of ·a groundwater flow system is primarily controlled by two factors: (1) topography, which provides the relief that drives the system, and (2) the permeability (vertical and lateral) of the material which influences the rate and direction of movement. It follows then, that the more that is lmown about both of these factors, the more easily de finable the flow system should be. Topography The major topographic feature of the study area is the Little Missouri River valley. The valley imposes a significant steepening on the regional eastward slope of the land surface. This local steepening averages slightly less than five times the regional slope in the southern part of the study area, about five times the regional slope in the center, and more than five times in the north ern part. The Little Missouri River is bounded by an area of badlands several miles wide (fig. 6 ) • Only a few tribu t;aries sustain a measurable flow throughout most of the 24 25

Figure 6.--General view of t he badlands borderi ng the Little Missouri River, North Dakota. r 26 year; the vast majority are ephemeral. The drainage pattern is dendritic and completely integrated. The land surface is broken by isolated buttes, some rising several hundred feet above the regional surface (fig. 7). Nany of these buttes are imposing features, but because of their isolation their total affect on the regional topography is small when compared to the Little Missouri valley. The Little Missouri valley is topographically bounded to the west and northwest by the deep Yellowstone River valley, to the north by the Missouri River trench (now Lake Sakakawea), and less abruptly to the east by several east-sloping valleys. Stratigraphy The study area is entirely contained within the

Williston basin (fig. 8 ) • The basin contains significant sedimentary deposits ranging in age from Cambrian to Quaternary. The sediments of primary concern in this report range from late Cretaceous to early Tertiary in age. The stratigraphic units considered in this report include the section from the Cretaceous Pierre Shale through the Paleocene Sentinel Butte Formation. Younger strata crop out, but they occur as isolated exposures on butte tops, and are not considered significant in the flow-system evaluations. The included discussions of the stratigraphy draw most heavily on two sources, Frye (1969)

a 27

1gur e 7 .--Ge e r a l v i e -.., of 1 .- olate d bu t e """ on the r eg a nal astwa a -ulop ng s ur a ce. The p icture wa s taken loold :ng we st from t he South Un i t of Th d ore ::- oos v e l t a t ional ·'.emorial Pa.,,,ke 28

..... _._,---

Montana WILLISTON BASIN North Dakota

Figure 8.--Generalized map showing the approximate bound ary of the ~iilliston basin and some major structural trends within the 'basin·. 29 and Royse (1967), who con~ucted field and laboratory investigations of tfle surficial exposures of much of this section and compiled the literature. Hennen (1943) con structed a west-east surface and subsurface cross section of the Tertiary and upper Cretaceous deposits. No other subsurface studies of these formations were found. A map of the outcropping stratigraphic units of the study area is shown in figure 9. The beds dip northward and eastward. Because of the importance of the relative permeabilities on the flow system, a brief description of the formations follows. Pierre Shale.-The oldest formation considered is the Cretaceous Pierre Shale. It is significant to the study because it is considered to be the basal impermeable bound ary of the regional flow systems that are established in overlying units. The Pierre crops out in the southern part of the study area, along the crest of the Cedar Creek anticline. The formation is composed of predominantely blue-gray marine shales that are as much as 2,000 feet thick. The contact between the Pierre Shale and the overlying Fox Hills Formation is gradational (Feldman, 1967, p. 37). Feldman describes the contact in outcrop {p. 41) in Bow man County (sec. 4, T. 131 N., R. 106 W.) as being grada tional through a·bout 10 feet, with a change from dark blue shale, containing gypsum, jarosite, and scattered concre tions. to buff or yellow fine grained sand. 30

Figure 9.--Geologic map of the study area, after Carlson (1969), Frye (1969), and Royse (19P7). 31

R102W RIOCW R."l8W R.q,w R'l!iW 1~-<1-~--1--aw -·--r -- -1 ~~ +--+---+---1·-__,!,...__ - --1t -- ; . l ' l f I -~ · 1 · l ,)J O---:J '- MILES :r-----+--...---.,..._-~-~- t- --- . :.. --lt I I ·1 ' ! .. j . 1 ~-i,r· 1'-"-'-::;.,,,..-1~f-.+-~ ,---

I i' l I h NORTH DAKOTA I I t 1 -----H ~------' .. L., I J I i LEGEND

D SENTINEL BUTTE I. >- a:: IDlllll TONGUE ·1 ~ RIVER I J ,~ T_JT ~ Ct: r: 1~ :·, Lu ~ LUDLOW I f\ ! ~ !·; · l. 1i ~ TULLOCK ------1 ~ CJ. HELL . I w CREEK ------I 0 L [___ J ~ ~ FOX HILLS l ~ i u ~ PIERRE. ! -,!

R10:::w RIOOW f? '18W 32 Fox Hil1s Form,3.. tion. -The Cretaceous Fox Hills Forma tion consists of near-shore and shoreline marlne·sand, silt, and clay. The formation is about 100 feet thick in outcrop along the Cedar Creek anticline, but thickens basinward to more than 250 feet in the subsurface of the study area. The upper part of the formation contains a light gray sand unit called the Colgate Member. This sand has a wide lateral extent and occurs in the subsur face throughout the study area. Hell Cree Jr Formation. -,.The Hell Creek Formation is of late Cretaceous age and is composed of nonmarine and · brackish-water clay, silt, and sand with some lignite. (I. Frye {1969) measured stratigraphic sections and indicated that laterally persistent sands occur near the top and bottom of the formation in the southern parts of the study area. The contact between the Hell Creek and Fox Hills Formations varies from gradational to unconformable (Frye. 19691 p. 22). Taylor (1965. p. 4) descrlbed a basal Hell Creek sand in eastern Montana which was medium to coarse

grained.,. This sar1d pinches out between eastern Hontana and western North Dakota. where the contact is generally marked by a basal Hell Creek lignite. lignitic clay, or bentonite (Frye, 1969). The thickness of the Hell Creek may exceed 450 feet in places. though an average of 350 reet is probably more typical. JJ Tulloc}(. Ludlo1;-J, and Cannonball Formations.-Over lying the Hell Creelr Formation is a sequence of Paleocene sediments, the Tullock, Ludlow, and Cannonball For mations, which because of complex facies relationships, are treated as a composite interval. The ·westerly Tullock and Ludlow Formations are of nonmarine and brackish-water origin and are time equiva lents of the more easterly marine Cannonball Formation. The Tullock Formation is not recognized in the subsurface of the study area because of a lack of sufficient criteria and control and the following discussion refers only ~o the Ludlow and Cannonball Formations. The Ludlow Formation is composed predominately of clay, lignite, and some sand lenses. The Cannonball For I, ,,~,, '·; mation is composed of sand, silt, and clay. Two tongues of' the Cannonball separated by about 150 feet of Ludlow Formation were recognized in western North Dakota by Brown (1962, p. 8), based on marine fossils recovered from the exposures. The Ludlow-Cannonball interval varies greatly in thickness from west to east, 'but 200 to JOO feet ls be lieved to be typical in the study area.' Ton~ue River Forrr~tion.-The Paleocene Tongue River Formation is generally a buff to light gray (in outcrop) seQuence of non.."!larine sediments that were deposited as the Can..'Ylonball Sea retreated from North Dakota. The sediments are priw~rlly clay, silt, and some sand and lignite. A 34 widespread sand lies at the base of the formation and may attain a thickness of more than 40 feet. Two relatively con tlnuous thick lignite beds or ligni tic shale beds are present? the Harmon lignite,about 150 feet above the base and the HT Butte bed in the uppermost part of the formation. The bright Tongue River conformably overlies the somber Ludlow Formation in the study area. The thickness of the Tongue River Formation is generally between 300

and SOO feet. Sentinel Butte Formation.-The Sentinel Butte For mation, of late Paleocene age, is the uppermost strati graphic unit considered in this study. It overlies the Tongue River Formation and differs from it by the presence of more somber-colored beds. Royse (1967, p. S) indicated that this color difference is predominantely a weathering phenomenon which cannot be used to distinguish the for mations in the subsurface. The two formations have sim ilar lithologies. but the Sentinel Butte is more sandy. The contact between the Sentinel Butte and Tongue River Formations was found by Royse (1967, p. 3) to be distin guishable on the basis of three criteria: a marked change in color in outcrop, a perslstent.lignitic horizon in the uppermost Tongue River (HT Butte), and the presence of a sandy unit in the base of the Sentinel Butte. The greatest thickness of the Sentinel Butte Formation is in the northern part of the study area where it may exceed 600 feet. 35

31~::1:-:.?cI'Y of b2~:roc}: s·s:~·.s.t.ir:::::·athy. -The strata overlying

the Pierre Shale a11 G pred.omi:'1a tely tine grained. Some pe:rsista11t; lignites are presa11t il'1 the Tongue River For-

~ation, and sand bees of significant lateral persistence occur L.1. the uppermost Fox Hills. Cannonball, and basal

'I'ongue IUver a1~d Sentinel Butte Forma.tions. Numerous local lenses of sand occur throughout the section. A cross section of the subsurface stratigraphy in the area of the South Unit of Roosevelt Park 1s shown in figure 10. The data for this cross section came ~rom logs of water wells in the area (appendix B). Two of the logs have been published (Simpson, 1929) and one is from a North Dalwta State Water Com.mission test hole 1n Stark County. The rema.inir.;.g logs were obtained from the· files of the u. s. Geological Survey in Bismarck. North Dakota. and through personal contact with private well drillers.

River alluvium.-The recent alluvial fill in the Little Hissouri valley is a signif'icant deposit in connection with discussions o-:f groundwater flow because of its relatively high per~eability. The alluvial fill averages three fourths of a mile wide .. At the surface it is clayey, sandy silt. Samples from seven test holes drilled by the North Dakota State water Commission i11. the South Unit of' 2oosevelt Parle in 196.3 {Project No. 1.326) are uncon solid.s:ced sand and gravel consisting mostly of q11.2.r::z. and limestone, with occasional ous

,:.::.1d. ;c.8tamorphic pebbles. The thickness is et.bout 20 ':;o 36

Figure 10 .. --Subsurface cross section in the center of' the study area.

- ---.._..._,.. ··------·-----·------. 2700, 2700

SENTINEL 2)00 BUTTE1(1' &UTTEF'M 11I-- ? -- ? --- - 2500 ALLWIUM ---· TONGUE RIVER fM

,' TONGUE _!-t~!'----- ? ?--- 2000 RIVER FM -- 2000 ------:· LUDLOW FM

LUDLOW.FM --7 CANNONBALL FM I I_,) '1 --·- CANNONBALL FM- LUDLOW FM--~· ISOO SEDIMENT 1500 C'.mNONf.:\LL---- tM --:-11-- I LUDLOW [M _ r- - fil SAND AND GRAVEL HELL CREEK ;L/ --- 0 LIGNnT FM IOOFL --- 13 SAND, SILTY AND CLAYEY SAND I MILE FOX HILLS - fl SILT fM IOOO 0 CLAY AND UNDlfFERENTIATED IOOO R. qq W.

T.13~ ---1-J

/ 38 JO feet.

Struc tu.re contour m2 p on the Pierre Shale. -Electric and radiation logs from oil wells (fig. 11) were used to draw a contour map on the top of the Pierre Sha.le (fig. 12). The elevation of tops in individual wells is given in appendix C. The Pierre Shale is as su.med to ·be the basal impermeable ·boundary of the regional flow system in the area; therefore, the Pierre can be viewed as a flow system

11 basement u. The map indicates that several structural features are present in the area. The structural feature in the southwestern corner is the.Cedar Creek anticline which trends from northwest to southeast. In the northeastern cornei- of the study area the southern end .of Nesson anticline is apparent. The primary center of deposition throughout much of the history of the Williston basin is just to the north of the study area on the western flank of the Nesson anticline. The trends of several minor structural elements are conspicuous as flattening or noses on the regional dip. This map also shows the rather low dips within the araaa The dip of the Pierre Shale is greatest on the northeastern flank of the Cedar Creek anticline, but there it is only about 50 f't/mi (about! degree). Farther to the north the dip is considerably less.· Because of' its low :permeability, as a result of its fine-grained character, 11111

Figure 11.--Location of oil wells used in constructing a structure contour map.

11111_..______40

F NORTH t J DAKOTA bJ

CONTROL WEU.

WI NDGS. WELL NUMBER 41

Figure 12.--Structure contour map on the top of the Pierre Sr..a.10~ 'I'he contours are in feet above mean sea leYel. .

,' t. 42

NORTH ih I f I DAKOTA I l '

I CONTOUR ON TOP OF aPIERRE SHALE ) l APPROXIMATE' POSITION ( OF CONTOUR

~ SURFACE EXPO'SURE ."'.ifl Of PIERRE SHALE CONTOUR INTE:RVAL "' 100 f'EET

R.IOOW R."18W

5 4J and because of its very low dip the Pierre Shale qualifies as a nearly impermeable and horizontal basal flow system bou..YJ.dary.

Hydrogeology

In the following brief description of the general hydrogeologic conditions a distinction is made between shallow and deep groundwater on the basis of physical and chemical data. The relationship ot' the two will be demonstrated later. Shallow groundwater In this study, shallow groundwater is defined as that which occurs in Quaternary alluvial sediment. The base flow of' the Little Missouri River is maintained by water discharged rrom the alluvium, therefore, the water at base-flow stage is assumed to have a chemical character similar to the shallow groundwater. Data were obtained from pits, shallow domestic and test wells, and surface water observations. The shallow groundwater is maintained primarily by contributions from three sources: (1) the deep ground water (bedrock flow systems), (2) recharge through the channel banks during periods when the stream stage is higher than the groundwater table (this increment con ·tributed to the shallow groundwater is called bank storage (Linsley, et. al., 1958) and is discharged to the stream 44 during the recessibnal stage), and (3) infiltration through the bed of ephemeral tributaries dur1ng runoff. Infiltration through the surface of the alluvial fill is not conside~ed a significant source of recharge • .rlost precipitation in western North Dakota. occurs as rain during the late spring and summer months. The soil prob ably has a high moisture deficiency (no figures are avail able) and therefore most water falling on the valley fill surface goes to replenish the deficiency. This condition ,;,;as observed during the summer of 1969 when an abnormally large amount of precipitation fell during a period of a rew weeks. Even after one week of rain, which exceeded 7 inchesi the wetted front did not exceed a depth of 3 to 4 feet. Recharge through the surface of the valley fill might occur during periods of very intense rainfall (several inches per day) or in areas of abundant drying cracks. Rainfall of extreme intensity does occur infre quently. However, the amount of recharge resulting from a storm of' extreme intensity is probably not significant in comparison to the total ysarly recharge from all sources. No observations have been made of the possible recharge

I" from snow and frost melt. Drying cracks have been ob se:rved but no quantitative data as to their extent or significance to recharge are available. The transverse gradient of the shallow groundi·ra ter is very low, probably on the order of 1 ft/mi. The sradient was so low that it could not be measured within the limits 45 of precision of the instruments being used. The longi tudinal gradient averages 5 to 6 ft/mi. High transverse gradients 1·mre associated with special recharge conditions, such as the release of bank storage, or infiltration through excavations on or along the valley fill. An example of localized infiltration was associated with an excavation about 1 mile south of the South Unit of Roosevelt Park. The site is a road-bed aggregate pit in bedrock abutting river terrace sediment. The pit acted as a collecting basin and impounded water running off an adjoining hillside. The stream channel was approximately 500 feet west of and JO feet below the excavation. During periods of high rainfall (such as the summer of 1969) a large amount of infiltration was induced through this excavation. The effect on the stream channel was apparent. The stream bank opposite the excavation underwent mass movement apparently in response to increased hydrodynamic pressure. The channel bottom at this location was very soft (almost quick) shortly a.fter the heavy rains. This condition persisted for several days. Isolated con ditions of a similar nature were observed in other areas along the Little Missouri River. As a result of groundwater contributions from several sources, some of which are transient, the alluvial water chemistry may show· considerable local variation. However, 1·;;ith the establishment of base-flow conditions in the river, the water chemistry soon reaches an equilibrium and does 46 not show significant variation over a distance of several tens of miles. The water can be generally classified according to the dominant ions present as sodium-calcium sulfate-bicarbonate water. Deep ~roundwater In this study, deep groundwater ls defined as that which occurs in sediment older than Quate:"ne,ry; more specif ically? it is water occurring 1n the Fox Hills through Sentinel.Butte Formations. The type of the grou.~dwater flow system involved ranges :from regional to local. Data · were obtained from wells (fig. 13) and springs. lilt~; A plot of static water level (measured from the land surface) against well depth is shown in figure 14. The plotted data shows two diverging trends. The trend above the zero-line shm·.rs an increase in water level with depth indicating that these wells are in a discharge area. All data which plotted above the zero-line were from wells located on the valley floor of the Little r11s souri B.1 ve r. The trend below the zero-line shows a decrease in water level with depth indicating that these wells are in a recharge area (these data were from wells located 1.5 to 2.5 miles east and west of the Little Nissouri valley). This qualitative evaluation substantiates the earlier assumption that the valley is a discharge area. water chemistry (excluding springs and samples fro::;;. local flow systems) shows both vertical and t0ral variation. One invariant throughout the discharge area Figure 13.--Location map of deep-groundwater wells .from which data was obtained. 48

o- ,.-,.n

NORTH T DAKOTA II./~ N.! . ! ]_ Tl 1411Ji N.'--"---~~-\ o WELL LOCATION '•i j '·.1

' c..-...:._ ___ ..;,-_-,--_+1-I , .··11 I ! ' ' +----. I . 1 J- ·1 I ~,---.--· ·_1.... __ L ---,--..J --.- ___ r__ L_,..... ___J • · I I , 'ii*• I ! 1 1 r · 1 ! 1 ····1·--1- : .. - -1- - 1-·. --! ! t ' • 1 i 1 .i tT l------+-----i----1----.---·- . J ·-~ •• ----I I I ! i ! ·l j ·r-~-T_..1_1 __ J _l__ J_l __ Lr__ ·-i--.l.·1 ' . . I I : I t-+- I I -;--t- ---+- ---t--- _j , . 1· r a' i • 1' I • I ' ' . I 1 I j • 1 1 RI04W RI02W. RIOOW R'l8W. +20 I

z H

0 0 0 0 0 0 0 0 0 \I"\ 0 0 \I"\ ,-I N N WELL DEPTH IN FEET

Figure.14 .. --Relationship or well depth and static water level. 50 and below a depth of a few hundred feet in the rec:r.arge areas is the almost complete absence of calcium and mag nesium.. The ·v-ra ters in a broad sense can be classif led according to the dominant ions present as sodium bicar bonate-sulfate grading to sodium bicarbonate from south to north. Water from springs and a few of the wells sampled is derived from local flow systems. r,1any of the springs sampled were associated with lignites and were located nea::i:: the base of' isolated hills .. The source of recharge was through the hill, and the flow path lengths ranged from a few hundred to a few thousand feet. Chemical analyses from separate local flow systems indicate high variation L~ quality, with ~ost analyses yielding values of total dissolved solids greatly in excess of samples from larger flow systems with flow paths at least a few miles in length. This is in opposition to the commonly accepted generalization that the concentration of total

. . dissolved solids varies directly with the length of flow path (Chebotarev, 1955). Obviously more than just flow path length needs ·to be considered in western North Dakota. FLO~v-SYSTEM EVALUATION

Potential Distribution

The potential distribution of the flow system is represented by three vertical cross sections (figs. 15, 16, 17) constructed at nearly right angles to the axis of the Little I1issouri valley. In constructing these cross sections it was assumed that steady-state flow exists. This assumption is justifiable because drillers indicate that present values of total head are not significantly different from original values; in some cases the period of time involved is several tens of years. A variation in total head of a few feet is consid ered insignificant in comparison with a total saturated thickness of more than 1,000 feet. Some reports of sig nificant decline in total head can be attributed to either faulty well completion or casing failure. The angle of intersection of the flow resultants and equipotential lines in these sections were corrected for vertical exag geration using the procedure developed by van Everdingen (1963). The cross sections (figs. 15, 16, 17) depict several important features of the flow system. (1) The potential .51 b 11111 52

"zsoo

II /-'TTLE MO. RIVER LE I ~r, . I - \ .,,,,, / I \ .!,- • / \ , ______,, I ' \. ------\ \ • / \0~7!_ ..,...,.,. :21, I I'--, _.,,,

~~ ,r -- • - ...... ,.... . _ ---\ ".ilu• • r---- - .I --.... ----- ______,_.,.- r--_ ------·------\ ,,,_, ------l --·- 2"100 -- _,,.,,,-, - ''ll't1 o2SO'- ..-- f \. .,; ..... ••., r ------

I? 102W. POINT OF 22 0 MEASUREMENT T / I 'iO r--.....,..~-//--t------1 ,..M/ a ,,, ~,- LINE 01" tQUAL HEAi) IN •EE.T - 27 ... DIRECTION OF MAIN FLOW

APPROXIMATE ti.OW RESULTANT INDEX

Figure 15.--Pattern of groundwater flow in the Little Missouri valley, North Dakota. The diagonal pattern indicates the approximate top of the Pierre Shale. 53

Figure 16.--Pattern of groundwater flow in the Little Missouri valleyp North Dakota. The diagonal pattern indicates the approximate top of the Pierre Shale. r··--~~*'"Lt '."'//1'"';1~, _( . ,1 J"wi~~.)1.""~ .., ~

280({ 2.800'

~:~' "";:_:, d , · 1 - 1 I \ - I I I I _____ .,, I I \ '------22.50 - I 2000 \ I I \ / I / I \ · "'"ll.2 ..1 •zzc-, · 'iiio" · •2i,~ 0 220(~ I \.• -- I ;~,- --· _I •l:10 =,;. --~ ~~ ~~ ------t J. ·f ------~~ ...... _ ' ~----~ ---2350----- \.J\ .{::"

1000

R.102. w. R.IOIW

I' _,,so.,, LIN£ OF EQUAL HEAD IN rEET ,~1~4- 2oo'L / 2000' .... DIRECTION OF MAIN F'LOW POINT INO£X or • MEASUREMtNT . APPROXIMATE FLOW RESULTANT o' o· .55

II')

Figure 17.--Patte:rn of' groundwater flow in the Little Hissou:ci valley, North Dakota. The diagonal pattern indicates the approximate top of the Pierre Shale. .. ,,,,b,jJ,~

2,00' uoo'

? I - - ? APP~ ox IM ATE BL[ /UTTLE[R' MO. / - ---, - -- - -,--I - -, I I WATER TA RIV ~-- ..- I J _ I 2000 _-:::-:,------::-.r I I ~~,-, .. ~·-· 1 - / / I I ==p..:~- cl / / I I \ c'i / / I ' '1 I \ .,-'\= I I I _/ \ ,.._ -- -~ / I I f \ _:=::=:=:-w;

- tlill ,t.22J"I ",ZllO Ct

7 .:·--'-'' "':'C:,~~W,('P1/1'.~0Z!/,W-'7CJf:',!1{!(1Y,(/$,$/&!/.///.///,X;f!~

'-10() '100. R 102 W R. 101 W. POINT or • MEASU~EMENT T. / l'H, .. -2150~ LINE OF EQUAL H£,A.I) IN / . FEET N.

'::-1~-~ 2oo'L-,. - DIRECTION OF MAIN FLOW ..... 2000 INDEX APPROXIMATE FLOW RESULTANT

·-----"'\'-, ~t~ ,,.. ~~ ':.: ~~-: ~~h.~:- ~ _-,~::._ -~ ~~ ~..:· ft .. r ~ "'~ ... ~,~-~"!\.'~ ~ 2c ..-· ~ 57 distribution is focused a.round a. groundwater s1nk that coincides with the trench of the Little !1issouri River. The potential decreases ·upward, indicating that the valley is a discharge area. (2) The movement of ground water is affected by the Little Missouri trench down to at least the top of the Pierre Sh.ale. No evaluation of oil-well drill-stem tests below the Pierre Shale has been made; therefore, no conclusions can be reached as

to t:he maxim·um. depth effect of the trench. (J) The flow components or largest magnitude (lateral and vertical) are contained in the plane of the cross section. Typical values, in terms of the gradient of the three components in the discharge area, are given in table 1. The values indicate that the longitudinal component is at most about 1 percent of the vertical. (4) The groundwater flow

Table 1 .. --Va.lues of gradient in the discharge area with respect to the flow components.

Range of values (ft/ft)

Lateral 2 Component 1 x 10- to 7 X 10-J

Longitudinal _I..!, Component 1 X 10-J to 6 X 10 .

Vertical 1 Component 2 X 10-1 to 1 X 10-

,. 58 lines are directed tm·iard the river from opposite sides of the regior...al system. The flow lines converge in the discharge area, which is approximately the same width as the valley bottom. The re.,;,:iona1 flow pattern. T.he regional flow pattern is represented (fig. 18) by a section through the center of the study area. The ground·wa ter divides are not symmetrical with respect to the river. The divide of the western half of the flow system is at least 22 miles from the valley, and the eastern divide abo_ut 12 miles from the valley. The groundwater divides correspond approximately to the i,, surface-water divides. In the eastern half of the flow system the groundwater moves up the regional dip from the recharge to the discharge area. The vertical components in the discharge area and the eastern recharge area are of similar magnitude,, where as the near-surface part of the western recharge area has a vertical recharge component, a·bout twice the ver tical discharge component. This difference can be ex plained by examining hydrogeologic differences in the ~low 'i field. The western recharge area -is 200 feet higher than the easter11 recharge areai resulting in a larger potential in the western recharge area; that is, the values of total head are greater than in the eastern system. However, the potential distribution around the discharge area is nearly 59

F'i,gure 18.--Pattern of regional groundwater flow. The c:ross section extends .:f'rom T .. 140 N., R. 106 W. to 'I'~ 139 N~" R.. 98 W.. The diagonal pattern indicates the approximate top of the Pierre Shale. 60

- -- 'o 0 'o 0 0 0 I- 0 0 N e ..."""'< • I I I ,. I () ~ I \ . l '-\ 0 \ ~ ... \ 0 \ ~----- i \ \ \ - - 0 " - 1- -0...."' ...... 1 - J i

'\ \ • \ \ '• • J "c9 l - / "' / / . /" / / __ ,,,/' I I / / ,..__/ •

'o 'o 0 0 2 \,JI 61 symmetrical, indicating that the greater potential of the irestern system has been dissipated in the recharge area. The closely spaced lines of equal head indicate (fig. 18) that the dissipation occurs in the vertical recharge component. Why is the energy dissipation restricted to the vertical component of the western recharge area? The flow path of this system is longer; why is the excess energy not used up over this greater distance? An examination of oil and water well logs suggests that the overall permeability in the western recharge area

is less than in both the discharge area and eastern re J. ., charge a~ea. Sand units of significant thickness are j' absent down to depths of 1,000 feet below the surface in the western recharge area. If the amount of recharge per unit area can be assumed equivalent for both systems, then a direct application of Darcy•s law requires that the system of lower permeability have a steeper gradient. Therefore, the larger values of total head and the steeper gradient in the western recharge area can be explained by its higher topographic position and 1t relative lower permeability. The total flow vector .. -T6th (1963) suggested that the longitudinal component (along the trench) of groundwater flo1,;r would be of little significance compared with the lateral and vertical components in a vertical cross section constructed parallel to the dominant topographic slope (essentially normal to the trench). If this reasoning ls 62 valid, a projection of the total flow vector on the plane of the cross section is a good approximation of the total flow vector. This assumes that the sediment can be considered homogeneous and isotropic; that is, the ratio of horizontal to vertical permeability is one (Kh:Kv, = 1.0). In the Little Nissou.ri River discharge area, the vertical gradient is at least 100-times larger than the longitudinal gradient. If the anisotropy were Kh:Kv = 100, the total flow vector would be oriented at about 45 degrees to the horizontal and the flow resultants in a vertical cross section would not be close approximations of the total flow vector. A value of anisotropy of 100 is not unlikely. I 1,;eyboom, van Everdingen, and Freeze (1966, p. 40) con cluded that the discrepancy between the flow resultant and total flow vector can be measured by installation of triangularly nested piezometers; this was not possible in this study. It can only be assumed, at this point, that the total flow vector is significantly inclined downstream {relative to the slope of the river valley) in the dis charge area. Further consideration of the total flow vector will be made in a discussion of the groundwater chemistry.

Groundwater Chemistry

Chemical analyses from more than JOO samples were evaluated during the study; over 50 percent of the samples

.:-ire from deep groundwater sources. 63

Deep .o.7rou:..·xlHater chemistri

The type and abundance of chemical constituents in the deep groundwater varies both laterally and vertically.

The cations are dominated by sodium in the regional dis charge area and below a depth of' 200 to JOO feet in the rechai~ge areas. The abundance of sodium in relation to total cations in the discharge area is shown in figure 19. The cations of all but four of the samples plotted are composed of 95 percent or more sodium. The figure contains Qata from samples ranging in depth from 100 to 1,500 feet below the valley floor. The anion portion' of the water ,: samples fror:i the discharge area is of variable character. ,, The chemical facies in the Little Missouri flow system are sulfate, sulfate-bicarbonate, bicarbonate-sulfate, bicar bonate, and bicarbonate-chloride.

Water from the Fox Hills Formation.-All samples from the Fox Hills Formation are represented by figure 20. The water is classified as sodium bicarbonate-sulfate in the southern part of the discharge area grading to sodium bicarbonate-chloride in the northern part. Only three samples from the recharge areas were evaluated; these are classifled as sodium sulfate-bicarbonate water. The data points in figure 20 are connected by dashed lines because they probably represent a gradational change~ However, ·che cha.np;e occurs rather abruptly over a di e of s.bout 8 miles (T. 144 N. to T. 145 N.). Unfortunately, no wells penetrate to the Fox Hills Formation in this

C 64

32 I JO..! i 281

26 ilI I :~j ' 20~I E-i <: 0 18~ i-'.l ~ 6 I' <: .L -· 8 0 14 I E-i ! 12~ (i) 10J

aJI I 6j 4 21I 0~ 0 4 8 12 16 20 24 28 32 epm SODIUM

Figure 19 .. --Sodium in relation to total cations in wat.er samples from the discharge area. 65

, !, I ,~.

ti::; ~I:' 1:

CATION$ PERCENTAGE REACTING VALUl:S ANIONS

Figu:c8 20.--Chemical analysis diagram of groundwater from Fox Hills Formation. The darkened regions indi cate .the areas of sample plots.

I // 00 .interval .. ?he variation of sulfate with respect to bicarbonate

is s:1.own by ::tigure 21.. A t:rend toward a decrease in sulfate relative to bica:rbonate from south to north is

obviousu The spatial distribution of fluoride (fig. 22) and chloride (fig. 23) shows a rather constant increase from south to north. The concentration of total dissolved solids (in reactive equivalents per million, fig. 24) is relatively constant throughout the discharge area, with the exception of the northern-most and southern-most areas. From the western recharge area (T. 140 N., R. 106 W.) to the discharge area there is a decrease in sulfate relative to bicarbonate, an increase in chloride, an increase in fluoride, and a decrease in total dissolved solids. Several reaso!"..able explana tlons of these chemical trends are possible. Chloride is very soluble relative to the other constituents and once in solution should remain in solution; therefore a trend toward an increase in chloride indicates long residency. Considering that the flow path is at least a few tens of miles long in the Fox Hills Formation and that flow rates generally decrease with depth (T6th, 1968, p .. 27), it ls conceivable that some water in the Fox Hills Formation has been there for at least; .several thousand and possibly several tens of thousands of years. Apparently there is a very limited source l 1 t of chloride in this system, because the values are much L Ir'~~------

Figure 21. --I·1ap showing the variation of the sulfate bicarbonate ratio in groundwater from the Fox : > J )i ~i Hills Formation. ~ . 68

Ti 1148i N.1... ---- ·1 r--1 NORTH ' : ' \ ' ( DAKOTA , b=1! __I . __ .. ·------'\

• J 8W IJ0' :Jt' I

?isu.re 22 .. --l!1s~p s;·10wing the variation of fluoride in ppm in grou...~dwater from the Fox Hills Formation. 70

--,- .,_ I I 1 ! !

RID4W R.102W R.lOOW R.98W --, !

Firru:re 23~--iYiap shm·0'"ing the variation of chloride in ppm ground.water from the F'ox Hills Formation ..

I I j I j •

l~0~--+--+--+--+--+--+--+----+--+---+1_··.---,/'·~1 I .

__J.._ i ___ j !

.NORTH \ T, DAKO:_J ,~~ I i I I _J N ~---- : i ! I LJ_r_L ___ I_ ' Tl ·-·--i-L-j jlf/1 I ti N.i . .r": ,?,, ..

Ti lY2J Ni,_ ---+--+----+---1rc----+--+----+---+----1: i :__I-;- ·jr]

-,--.l.i !

'*'• I R.!OOW R'ISW. 73

?:.cttl'.'-<3 24 .. --Hap showing the variation of total dissolved sol in epm in groundwater from the Fox Hills Fo:rraation. R104W R i..-::;;;02;...;.W.;.;,.. __ R.100 W ~;..:.;R...::'lB:...W.:..:;_· _-,;.:.;.R...:.%=-W...:.·.---rR-''l_'1 _W TL_ I "\ ~· 152, .v;:,"i,__A ~,,..1~.I -, : I : NI \..}i '· I ' I I l / ~'""'1.- - -- -· + -+----i---i--_.;~------·-t---·- 4--

! ij i -, II i \r ' I I {1 Tf--]~ ·1-----\ 150~- I - 1 N. W __.;.....------+---.;_-----·~ -f-- , I I

., '

j I Th __ c_ IYOj ; Niyt"!'1-- i i-i-- T• i 138: i Ni

- ' R 8W 75 lower than might be expected. Nevertheless, there is an increase northward in the discharge area. This may indi cate the presence of a significant longitudinal component (northward) of the total flow vector, or it may indicate that the west to east flow length (normal to the valley axis) is greater to the north. Possibly more chloride is available in the northern end of the study area (fossil water?) and the increase is not reflecting' flow-path length. Fluoride is similar to chloride in its chemical behavior (though much less abundant) and explanations of fluoride variation analogous to those for chloride varia tion appear plausible.

Total dissolved solids remain relatively constant or I" ,:, :; show only a slight increase northward. Assuming that similar lithologies occur throughout the study area, the nearly constant concentration of dissolved solids indicates that flow-path lengths are nearly equal; this tends to negate the existence of a significant longitudinal flow vector. The removal of sulfate from the system does not appear related to length of flow-path. A discussion of its disappearance is included in a following section.

~Jater from the Rel 1 Creek Forrna tion.-All samples from the Hell Creek Formation are represented by figure 25. The water can be classi~ied as sodium bicarbonate-sulfate grading to sodium bicarbonate. The variation of sulfate with respect to bicar·bonate (fig. 26) shows a decrease in sulfate northward. Chloride (fig. 27) increases south to ?6

l'CHCCNTAGl RtACTINil VAlUCS

Figuxe 25.--Chemical analysis diagram of groundwater from the Hell Creek Formation. The darkened regions indicate the areas of sample plots. i I !

i:' I

I f

Figure 26 .. --:Viap shm·ri:ng the variation of the sulfate bica:..~oonata ratio in groundwater from the Hell Formation .. 78

RI04W R 0.BW R,q4w J52,T~ ' N! r."$, il\-+----!----!----4--'---..;.._------i---4.----1 I !; Tt-·JJ--i--+----+--+---+---+----+---1--+---+-~ 150; N. V------1---+---+--+------.... i __ ji T: !l/8,

N. r-!-+---+--i----,--.;.._(l~,....,..;::,....Jc---_,.....b.:f'--+--1 i ...... 'i J NORTH Tf-+---+--l--.:...:J;l.L:.l!--1-----1---+----+----+-----i DAKOTA 14,i N. ! t'---,r---+-----""'4--""'"-+------+---4f---'-----' I I • ' i Tf-J-,-..L--,-. .L. -

14'1!N.! I · i. ! ! I i

. ' l I ,. '

,~111\1 t i i II

RlDC:.W RJ04W RI02W R.100W R.'18W 79

Ii'ir:;ur0 27 o --tia:p showing -c:.:.'le variation of chloride in ppm in grounuwater from the Hell Creek Formation. --

. -,------·- _/ J~ O---'..J "MILES \

i h NORTH Tf l \ DAKOTA IN.i 'I" i b) ____ _j !------··-""-·· ·+ ! T~--,--'·-,-·-1-L.] .

Th 138! ' Nj ... , • I I I ! . . l. .

-----··------·-----' .. ! ! i ! .Ll.

·-----tr ~ i ; is i : ! 'LL.. ____ .1...... _ __.___ ...... _ __ ~_ ...... ___ ..1_. -- - L.-_l_--~· _j L----R-.I-OG._w_.___ R_.10_4_w--:---R-.1-0_2"_N ___ R_.1o_o_w ___ ,. R_. 9_sw_.______l

---- C 81 north, then falls off to a low constant value in the north. The distribution of total dissolved. solids {fig. 28) shows a northward increase. The near disappearance of chloride can be accounted for in two ways: (1) a lithologic change northward with little or 110 chloride available for solution, or, {2) flushing of the system by either very rapid turnover of water or 11 fossil 11 flushing resulting from Pleistocene glaciation in the area or" the northern Little Missouri River and to the east of the study area {Clayton, 1969). However, the minimum amount of time since glaciation is about 10,000 years and assuming flow path ler,,gths on the order of 20 milest the rate of groundwater movement would have to be less than 10 feet per year to retain any Pleistocene water .. A groundwater flow rate of 10 feet or ss per year is not inconceivable; however, it is improb able that an adjustment toward chemical equilibrium could not be attained in a period of 10t000 years, unless glacial flushing was so intense that it removed all soluble chlo-

' rides from the system. Flushing from below would not explain the disappearance of chloride, but {J) a decrease in 1.:pward seepage from the Fox Hills Formation, which contains abundant chloride in this area. could account for the chloride reduction in the Hell Creeke The general northward increase in total dissolved solids appears contrary to the chloride distribution; the generally accepted view is that both chloride and total ---...'.,.. l

Fisure 28~ --:.~ap show·i:rJ,:~ the varia-;;1.on of the total dis solved solids in epm in groundwater from the Hell C:ceelr: Fo:r·mation .. ' .

C 84 dissolved solids increase with a. lo:c.g flow pa th. A possible chemical mechanism account· for an increase in total dissolved solids but not related to flow-path lensth is included in the followir1g section. Hater f:rom _the Cannonba11 Formation. -A plot of chem ical constituents {fig. 29) in water from the Cannonball Formation indicates that the only chemical facies occurring at this stratigraphic position is a sodium bicarbonate type. Sulfate and chloride are essentially absent through out the area. Total dissolved solids (fig. JO) in general increase south to north; both sodium and bicarbonate increase northward. l '

i-Jhy should water at this position in the flow system be so consistently devoid of sulfate? Either sulfate is not available in the unit or it is being removed as rapidly as it is introduced. It is not likely that sulfate is not available because the Cannonball is overlain and underlain by sediments containing sulfate water (at least in the southern part of the study area), and as a result of the groundwater flow (as potential distributions indicate) there must be 1ntercl:"!B.nge at various places in the system.. Therefore, it seems probable that sulfate is being intro duced into the formation and is being removed by some process .. l,.n explanation for the removal of sulf~~e involves the rec.uction of sulfate to suli'ide. This process was con cluded by Cederstrom (1946) to be the mechanism generating 83

:-L1·' NORTH i DAKOTA f ; \ µ \

T:------+- 142/ . NI-!_ __,.._~--+---

!) •

. J I L1 1~1 T;l- _f ___ .._ .J T ·1 __ _i_T__ -,-.L 1 l __ l 132i I : • I i . N. l_i------~:?.=· ,-I _ __,..1 __•___ . ---1 ! : :n.~ i I

-'-I-..--L----~:-;:-:J u·-----~----c,~---"----R.10'-W RIDYW Rl02W R.IOOW R.9 8W 85

iii,

CATIONS f'(J!CCNTAGE REACTING VALUES ANIONS

Figure 290--Chemical analysis diagram of groundwater from the Cannonball Formation .. The darkened regions indicate the areas of sample plots. ZQ

I.' i F·igu:i."'e 30, --leap s.howi:r.g the var1a tion of total dissolved ~~'; solids in ei'.)m in groundwater from the Cannonball Forna.tion .. 87

R.':SW R.'l(.W

I. 150' N. ,,,_,---i------1---....._--1-----1-----1----1

___ jI

\ h: NORTH DAKOTA

Ir -----1- - _j_' ' . !

T! 11-10! ! N. '-·---+-----t--,--

Tf 1381 N. ;;-'-+---t--t----f<::--~'--+----i---+--1----;----,

·,--- --,- . I I

132iTi1-· NJ. i I i i I i RI04W R102W. R.IOOW R.98W r' 88 ' carbon dioxide and resulting in increased bicarbonate in I~1' ground.water in Virginia •. Feely and Kulp (1957) employed reactions rzsulting from sulfate reduction to explain salt-dome sulfur deposits. The reduction of sulfate occurs when it comes in contact with organic matter. Using the simplest organic

compound, methane (CH4), Krauskopf (1967, p. 276) presents the reduction reaction

2H+ + S04-- + CH4~H2S +CO2 + 2H2o AF0 = -24. 8 kcal (7)

in which sulfur is reduced I~rom a +6 to a -2 valance state.

This kind of a reaction has been demonstrated in the laboratory only with more complex organic compounds, never with methane; therefore. the reaction is only symbolic. Reduction in the presence of organic matter proceeds too

slowly to be significant unless a catalyst in the form of anaerobic bacteria is p:resent (Krauskopf, 1967); this group of sulfate-reducing bacteria are classified under a

single genus!> Desulfovlbrio (Feely and Kulp, 1957, p. 1809).

'.'2here is evidence for the existence of free orga.nic matter

in water from the Cannonball Formation. A flowing well

(sec. 2) T.. 141 N ~ j) R .. 101 W.) was observed to be period- ically emitting mi::.1.ute globules of znaterial which rose to the surface of a stock tank end produced an iric.&scent sheen. The frequency of emission was about 10 secon~s over a pe:r.iod of obseTvation of several minutes. Iridescent 89 surfaces on other stock tanks had earlier been noticed but 11ere the ti~e considered to be a result of CO;;.- tami:c.ationo Apparently some immiscible liquid is present in the formation; an organic compound seems probable. One necessary i11.gredient for sulfate reduction is apparently readily available in the Cannonball Formation. Feely and Kulp (1957, p. 1810) cite evidence indi cating that anaerobic bacteria are known to occur at depths exceeding 1,500 feet. They also indicate that the optimum bacterial growth is between the pH values of 6.J and 8.,6 (p. 1809); the pH values of Cannonball water are contained within this range. The products of sulfate reduction indicated by eq-.1.a.tion 7 are hydrogen sulfide (H2S), carbon dioxide

(co2 ) and water. Carbon dioxide and water can be con sidered to be respiration products of the bacteria, and the energy loss (24.8 kcal) is the amount utilized by the bacteria in the .conversion process. The reduction of sul fate is but a first step in altering the groundwater chem istry as a consequence of the products of the reaction

(EzS and co2 ). Hydrogen sulfide is a weak acid and can dissociate:

_..:::... .,..,.+ + ,.,.s- H2 S -.-n.· n • (8)

io:.'lizatio:1. is incomplete some H2s can rer:.10.in in solu tion as a dissolved gas. .fl.... ~ odor HzS was noticec:. .:-,t some wells bottomed in the Cannonball. The second product of 90

tion 7, co 2 , combines with water to f'orm carbonic acid (H2co3), which can ionize to forn hydrogen ions ( ) and bicarbonate (Hco3-):

(9)

'I'he increase in hydrogen ions as indicated by equations

8 and 9 can result in the solution of Caco3 to form ca++ and .r~~¥c,.. v3 - : (10)

The direct effect of sulfate reduction is an increase in

Rco3- (high values are characteristic of the Cannonball Form.a tion) and Ca+-:-. However, it was. noted earlier tr..a t

Ca+T is essentially nonexistent in the groundwater (with the exception of the upper 200 to JOO feet of sediment in the recharge areas). The removal of CaT+ could be the result or cation exchange in clay minerals and zeolites.

A general example of the process involved for zeolites is:

Na-Zeolite + ca++~ Ca-Zeollte + NaT. (11)

This reaction would increase the Na+ concentration. The net result of reactions 7 through 11 ls a decrease ::::.o, - ._,, 4 , an increase in Hco3- and Na+, and as a consequence an increase in the total dissolved solids. These ::cesults are che.ra.cteristic of water samples :f'rom the Ca:'11:o:nball Formation, and the qualitative reaction scheme

:)resented ls believed to ·be a reasonable e:x:plar..ation of 91 observed chemical cl1.anges. These types or reactions might also account for chemical.changes occurring in water fro.:n other units in the northern end of the study area .. (·b.ter sa.rnPles f::...~orn the LudJ.ow and Tong;ue River For- m,:>.tlons.-The Ludlow and Tongue River Formations are the highest stratigraphic units sampled .. Water from the Lud low is represented graphically by figure Jl. and can be classified as sodium bicarbonate-sulfate grading to sodium bicarbor...ate (south to north). The Tongue River Formation contains the shortest and shallowest flow paths of the wells

sampled., Grou:-1.di·m.ter motion in the Tongue River Formation

is more affected by local topography than any of the deep er m~itsu These conditions are reflected by the var1- abili ty of its water chemistry, which is represer~ted by figure 32 .. Chemical facies range from sodium sulfate bicarbonate to sodium bicarbonate. As with previously discussed units, low values of sulfate occur in the north ern part of the discharge area. Some of the highest values of total dissolved solids were obtained from sulfate-rich samples of Tongue River water, indicating that abundant soluble sulfides and sulfates a.re present in the sediment or the recharge areas. Samples f~om snrings.-A few samples from springs located along the toe of the valley wall of the Little

!1issouri River were analyzed. The springs were associated ·;,rith lignites and the groundwater flow path was :relE"'·cively short, on the order of' a. fei·.r hu.Yl.dred feet. The samples 92

CATIONS P£RC£(1TAGE RUCTING VALUE$

Figure 31 Q --Chemical analysis diag1."'am of groundwater from the L-C'..dlow Formation. The darkened regions indi cate the areas of sample plots. 93

CATIONS l'CHC[NTAGt R[ACTING VALU[S ANIC>NS

f::; I' F.:..guz·e J2 ~ --Chemical a:n.alysis diagra:.:n of groundwater from 10 -;-1.-;-:::.c., .. _\;;;, 'T'o..,,.,r-···c- •-i:)U.C B.,- .J..V"·-e,... _ -"Ro.,.,r·•~--..,.!.+- ~ o·.,.i•o mll~e~ • dark· e""ed.ir..L. regi- O""S._,. indicate the areas of sample plotse i·Jere CO;;;.lJOscd of 1Jredominately sodlurn sulfate water (f • JJ); however one sample contained JO percent (of

total catio:;.1s) calcium and magnesiu.:n.. Spri:'lg locations along the valley wall were marked by accumulations of whi sodium-sulfate salts. Spring water has a chemical character similar to samples from shallow wells in the discharge area with the exception that the spring water contains more calcium and magnesium. The largest values for total dissolved solids (upwards of JOO total equiv alents per million) were from spring samples. Ca1cium-m.ai:i:nesium facies.-Calcium and magnesium concentrations in groundwater are apparently inversely related to flow-path length. Therefore calcium and mag nesium decrease with depth in the recharge areas. Copies of water-analysis worksheets were obtained from the North Dakota State Department of Health and values of total hardness (calciu.~ and magnesium as Caco3 in ppm) of 169 samples from all parts of the study area were used to evaluate the decrease of calcium and magnesium with depth. The :majority of these samples were from private

:·:ells.. The samples were collected by the owners in most cases. The only analyses evaluated were those with re ported depths and locations. Samples from the Little Mis- sou~ri valley were excluded from the evaluation~ The re sults (table 2) indicate that the amount of calciUJn and uagnesiun does decrease with depth and that a rat:1er e.brupt

G occurs between 200 to JOO feet. Below JOO feet the 95

PERCENTAGE llEACTING VALUES

;•'igura :33. --Chemical analysis diagram of water from s PI' i11.g s • IWiiaflttftlllldllr11ro·t1lW11\11Mf"tllrr 1h11ii*:i ~lfi\tlill', ., e'fI ll'll'i, (<,if NII , 1111, r i'IOI...... ij'? ' ... ·. •1 ·'"Y'I. '. ,.·. ··.··»,. . '. . ,,. . , .. ·· . · ...... · .·.. . . · . . . ·,·.. . ,,.·. ••.. · · · 1 ,~ r 11 I Uilltiiillffl lh]ISrfJilflff!'tiilW'rl'J"'~I•''"fjf•J1if1t11lll'.1iilJtll(lliJIJ)1ifri

++ ++ blo 2 c ~H~Varj.ation in ppm ha:cdno s s ( Ca as Caco ) with depth of 169 wa samples from the recharge arcaR, 3

~-~ ,.t...,., ·.. -•< ..... ··'"''·"'"''''""""""- ·"'"'" ,_-.,.., ___ ,u.;,,::;•, ..hM"",· .,, •..,""'"'~'= "~ ~, ,..,,..,,,,,.v.·4:,•.f·,iy~_,..,.,,.,,..._..,:,.,•·"·"'..t1 """-" Y~u=:.~s··.. ..-,,::.·,:~"""""" ..,.,.,,,, .,...,,,..,.,,."::, .. ·::,., "'' ::::::.•. _,.. -. "·=· ,,o,.- " • ···:v-.""· ,., •..,~..,--_,._ ""'""""''"'-"·"·'-~"'~ ..:..: .- ..,_,. t--,,.,,.. ___ ...... ,,..,,,_,+-· .,,,,....,,_,,~ •:,_.,.,_,,,,_"'"'-~'"·..,.,.·~-"'"~ .... ,. .,....,,.,...,.~,.,.- •.,, .. ...,..,.,_,..,. __ "''-',.;,""~"'---'"'"''"'"''-·-'"'''_.,.,.,,.,~:.:;rac-·~o."'--- = J<-t., .....-. ,·•~"···"''·""" - ...~ .. ,.,.,..,,¥.·=: u,:;.,··,, =-· .,,.,.- ''-·'""""'' ,..-.~-..,,., ·ta.:t·•-,,.,, __,,...,.,, . ...,.."'"·'·-'•V· i •. ·•-·•""'<'•l<· ..... , Depth (ft) 0··50 5t•,100 101~

Percent of total sample '22.-5 2463 1554 10.,0 4, • .5 3.0 5.3 15, O

-; ..,_....,."""'""'""r,·..-.,--_..,.,._ ... ., .. _ . ..,.._. --~-;::IJU~·-.,.._,.,.,.,.,....,,.,.,,..,.-,.,.,u,._..._.._y,,c~soi;..:c::-._.,-.....---.---,::;:a,t.;o,:M,.,...... ,.,...__,_,. _____ rn:.>J_l_'"n"' __~- -=·~-·i"''""_.....,_,..,..,,_,.,.r,,.,.....-...,, ..-.- ..... ,. ,_ ... ,,_.,.,,.. __ v,oi-.-,,.,,,,~•'>u,,,..,....._ ___.,

Hlgh Vfalne 3230 231.0 988 1012 81+0 200 h,o '°O,

Low Value 9 6 5 10 1.4 25 10 1 _.,.,,._,,.,_... -,,,_.,.,.,...,..,.,"°"""...--"'.,....--=-,.,.,._ ____.~~=--..oo.. __ _,, __.._...... , __ ,_,, . ._;,;;,,,:,~-=--.,,.----~.----~~.--.-..._""' _ __.,,.,.,_.,,...,._ ...... ""..;,. ,,-.,...·-•ec ___ .,.,..,_.,_.,..,..,.,..~.,--.,. ....- .. .,..,. ..,

Moan 793 578 301 235 210 64 19 15

Stand:,,:. Devlr-,t 718 l.J.68 285 228 308 68 9.,9 10 97

values are equivalent to those in the discharge area. J,.....,_

analogous situation i':a s observed by Renick ( 1924) in r.:cnta.:na. He attributed the decrease in calcium and magnesiu:;i and increase in sodium to cation exchange by silicate minerals .. r1inerals occurring in the sediment of the flow· system

that; are capable of cation exchan.ge are clay minerals (in ir.1.tere;:canular spaces and in bentoni te beds) and probably zeolites. A general equation for cation exchange for

' zeolites (equation 11) indicates equilibrium between Na+ <' 1 • ..i.. I a11.d Cn T • members. Sodium is readily given up in exchange for ca++,.. even for very dilute ca++ solutions. However. the reverse reaction (Ca-Zeolite exchanging ca++ for Na+) occurs only when the concentration ratio (Na+)/(Ca++) is much greater than 1 (Krauskopf, 1967, p. 162).

llfhy must the groundwater move through at least 200 feet of sediment, on the average, before exchange equi librium is established? Some of the most important vari ations to be conside:r·ed are {1) the distribution of cation

exchange minerals in the sediment, {2) the rate of cation length of time that the water has been in contact with the sediraent (the rate of downward move- ~ent), and\~)I I possible additions with depth of ca··,J.-l,... and ng·- -t-+ to the water in this zone. {1) The distribution in the sediment of minerals with

cation exche:.nge capacity is unknown. Renicl..: ~1924,

l). 70) indicates that zeolltes and clays ·with high exchange 98 cs:.:;s:.city Ci.O occur ve1--t:cally throug;hout an equivalent

Dakota .. (2) The time required for cation exchange in clay minerals ra~ges from almost instantaneous to several hours, depending on the conditions and minerals involved (Grim,

1c"·-·- )00 ~ p.. ?OO)- , " neaction time for some zeolites may be (3) G:roundwa.ter moves very slowly through most sedime1-1t; itl tl1e sectio1'l. Thus, a givet1 pa1~ticle of water shoul& be in contact with most cation-exchange r.'linerals lo~s enough for nearly complete exchange to occur .. (4) The

-cn.1c• • • J:;:en:.:..-:g " or- ·c1'us• • • zo11e •oy aa.'di· +-1·.., ons_ oi-"-- Ca++ and i'-on,o- ++ with d.epth ca.nnoJc ·be accui~ately evaluated t1ith the available

A rcasohable explanation of the thickness of this zo:::1e of groundwater rich in Ca++ and l1ig++ is that it is a

~es~lt of the near-exhaustion of the exchange capacity of the sedime;.'l t. ~ The water chem.is try :!:'eflec ts the pre sent position of a dow~ward migrating front of altered sediment (the o:rig~nally Na-rich clays and zeolites have been altered to Ca types)~ with the most complete alteration occurring near the surfaceo Hany f'acto:rs relating to diagenesis of the sediment a~a involved in this process§ If the surf&cs of the sedi- r:,e::~·c rerr:ains at the same position with time (low·ering by e::::.:-osicn is minim3.l), the thickness of the altered zone of c:::cio:c-1 e:xchar:r:e minerals would increc:.se with time; likewise, 99

.!..../.. depth of Ca'· and Me;++_rich groundwater would also inc:cease. ::i:owever, erosion in western North Da1rnta is

.;..-.-.~-·"'a.' C::::.J.-'J.. (C•ay·"'o-..,-i.. V .I,.., i If the rate or surface loweri:".lg is eq_ual to the rate of migration of the doi-mward moving front then the thickness of the altered zone would be maintained with time. The relative rates of these two p1~ocess are ur.Jrnown. Summary of the .o:roundwater chemical flow s;ystem.-The variation of chemical facies of the Little Missouri River g:;.."'ou:1dwater flow system at first appears to be best eval uated on the basis of individual stratigraphic units. :t,'f.any or'' the observations appear almost contradictory to the conclusion that the Little Missouri valley is the locus of convarging groundwater flow lines of a single regional flow system. There is typically much vertical variation of bicarbonate and sulfate in the study area. The relation ship between bicarbonate and sulfate in samples from all stratigraphic horizons in the discharge area is shown in the scatter diagram, rigure 34. The samples with the highest values of sulfate are from the areas of the short est groundwater f'low path. Several conclusions can be d.:ra-wn from this nonlinear plot. (1) Sulfate readily goes into solution in the groundwater of western North Dakota and is an indicator or your..g groundwater. (2) The trend a:~pea1~s to be asymptotic to a reacting value of 2,JJJ)roxi- me.tely 8 to 9 equivalents per million of bicarbonate. This value is 1:nterp:.~eted as the bicarbonate base line and

I • 100

8 7 ,. 611------.------.-~.-.-----,----+ o 1 2 J 4 .5 . 6 7 · 8 9 10 11 12 13 14 15 16 17 18

,,) ' epm SULFATE

Figure 34.--Bicarbonate as a function of sulfate in ground water samples from the discharge area. 101 probably represents the initial amount of HC03- formed in the presence of free co2 in the re ct.:....:::ge areas. ( 3) A disproportionate increase in Hco3- relative to the decrease in so4-- is a result of sulfate reduction; Hco3- and S04- comprise at least 90 percent or more of the total anions in all but .a few samples. '.Phe very low values of chloride in samples from all but the deepest parts of the flow system probably reflect an absence of soluble chlorides in most of the sediment. The marked decrease in chloride from south tq north in water from the Hell Creek Formation may be the result of flushing by a very active flow system induced in the north ern part of the study area 'by Pleistocene glaciers. Or the decrease in chloride may indicate a decrease in upward seepage from the underlying Fox Hills Formation. This could indicate a separation in the flow system in which the Fox Hills Formation no longer participates in the Little Missouri River flow system but assumes a more longitudinal flow component. A lack of sufficient data prevents a more thorough analysis in the northern end of the study area, and the complexity of the water chemistry makes further elaboration on the total flow vector difficult. A generalization of the Chebotarev sequence for the Little Missouri flow system, beginning in a recharge area. might be as follows. 102

Eco.,- or HC03 - + u·""'O 4 -- --;;11'- s O4 -- + ECOJ - .)

804----;;i"' S01_;, -- + r~C03 - -;,... nCOJ - + S04 -- -~

The general vertical variation in cations in the regional flow system {west to east) is shown by f'igure 35. The distribution of anion facies {west to east) is shown by fig1.U~e J6. The variation of anion facies along the longi tudinal flow component {south to north) in the discharge area is a.p:proxi:r.ia.ted by figure J7. It is obvious that the presence of these alternating facies prevents placing a single analysis of bicarbonate-sulfate water at a unique position within the flow system.

li..na.lyses of water samples from oil-well drillstem tests of formations just below the Pierre S.b.ale indicate that on the average this water contains about 100 times more chloride and at least 10 times more total dissolved solids than water from the Fox Hills Formation. Apparently the Pierre Shale forms a signi:ficant groundwater-chemical bou..Yldal"'Y in western North Dakota. Chemistry of sha11ow 12:roundwater The chemistry of shallow groundwater samples may show considerable local variation in amou:.1t of the major con stituents. Figure .38 represents two samples collected at the sawe time from approxi:r.iately the same depth be the vra:tsr table. The sample wells were aligned normal to the . 3000' 3000'

~-· 0 'u)

vu..__------==i"oo·

20018000 D 10.t~ c1•+ Mfs:.'lO% D. N/>qO%

Figu:c·a 35. ,.. -cross section shouing the general reglonal vertical varisi.tion in cation facies. rrho line of the sectlon corresponds to figure 18. 3000'

? ..... 0 .{::- .? .______...:______~-======:=! .. oo· kJ soi:; oR so~-HC03 . D HCOi-SO~ 2'°00 so~-HC03 HCO.i

Flcu:ce 36.--Cross section showing the regional vertical variation in e.nion faoles., 'I'he line of the section corresponds to figure 18. 1 1 ""'"" -· r 11 Iii 1Fillif'llltiiU1i'lllit11Mf (t wti'\i"11±iiti 1\r,rn ini'~1* frwa111/Wfiltlffl#ti,th1rri'~iliti~o'.lilllllfllll--

s N 2~oo'r-,·~~iiijt~~J~@rf __ r·-' 0 so/-LIN, I.J, D Hco;-soy-- -- PIERRE SHALE

-----·------cf

Figure 37. -·~Generalized cross r;ection showing the south to north variation of anion facies ln the dlscharge area. 106

I £ i B + + (Y'\ (Y'\ rl + + 0 0 ..:::t C) al bO 0 C) 0 C) ~ ::r:; rt.}

~ Sample No. 260 Sample No. 261

Figu:~c J8 .. --~·later chemistry of two shallow g-:coundwe.ter sampl0s indicating dilution resulting :·ram seepage f::com the Little Nissouri River. 107

:c· iv ex· c l10..nr10 l ;

..s.11d. :r:m-:~ber 260 i,:as ?O feet f:cor:l the rive:.~. The sample nea:rect

st:rtc;::::.m resulted from dilution of the shallow .srou:nd-

·,~·u by seepar,;e f:rom the stream; large a.mounts of rainfall

£'lad resulted. in prolonged high stage. is difficult to

scribe the ave:cage shallow groundwater chemistry because

o:~ this type of transient condition.

A fetr widely spaced (covering about 120 river miles)

samples of s]:1..allow grou...."ldwater. collected during extended

:periods of low stream stage. are assumed to be represen tative of the normal chemical conditions (fig. 39)o The ·waters are predominately sulfate-bicarbonate; calcium plus 2agnes~um comprise from 30 to 50 percent of the total cations .. Most of the samples showing the lowest percentages

of sulfa are from the northern end of the study area. Eowever, the limited amount o-:f data does not warrant pro posing this as a real trend~

Stream flow at low stage is maintained by groundwater

seepage; therefore, samples at low stage should be indic- s~ive cf tha chemical character of the groundwatere It was obse:-cved that the ttle JYiissouri River consisted of reac;1es cf alternating increasi11.g and dec::cea.sing flow at

-i ·"1.e. ,"'. ,'.. ,~o-·,,s.,... 196? ...... (..A,,.., -.i,,J. 4•'-''"f2) <,A,. V,. I f several discharge meas- the course of one 2.::t~:;.c;:c:-:.oon.

at t::1e sout:-.e::::n bounde.:ry of the South u~1i·~ Ti"'

::::1oosevalt ParJc, where the d.ischa:r-ge was 17. 5 cf s * 1rreasure- --11 J

SUPERSATU.?,.. ATED

7.5 r=; [:;4

.-~-.jr-• ::::i U) ,._.,~ 7.0 ~ r ~ -aI-,-, 6.5 I 6.o

UNDERSATUHATED R I a i • 6.5 7.0 7.5 a.o 8.5 pH C.ALCULATED

Figure 420--Relationship of measured to calculated pH for sor::.e surface-water samples .. The calculated· pli is for solutions in contact with calcite. The stippled area indicates assumed equilibrium. is e,ssun8d that a larr;e quaYJ.tity of t:r~e shallow grour1d:1ater is a rzsult of seepage from the deep flow system, only one aspect of the shallow ground.water chemistry remains U..."'l-

.. !-.J- .. + .. t- :r·esolved.. Tl'le concentration of Ca· · and f:/Jg in the deep :--;:coundiirater has been shown to be consistently very low beneath a depth of about 200 f'eet from the ground surface

J -L... ' ' in the :recharge areas. whereas Ca·· and r'ig ;-, comprise 30 to 50 percent of the total cations in the shallow grou..."'ld- i·w.ter. It was concluded in the previous section that the upp,::n~ 200 feet of sediment in the recharge areas has probably had the original Na-rich zeolites and clays altered to a certai:.."1 extent to Ca-rich types. The bullr of the fine gr·ained sediment filling the valley has been derived from erosion of sediment in the recharge areas. That sediment contains Ca-rich zeolites and clays. It was also noted 6arliar that the equation for cation exchange (equation 11) is reversible only with a concentration ratio of (Na+)/

(ca+-r) rc,uch greater than 1. However, this is the case in deep groundwater, which in the discharge area has a concen-cral,J.on· ~· ra-c·1 o or~ a:c· 1 eas-c · 90 :i.~ The ca+T a~id,., .1.'lo~1~++ in the shallow groundwater are increased relative to Na+ by cation exchane;e? w·ith equilibrium being maintained as -enc co11ce:1. ..Cre~tion ratio approaches 1. '.I'he :n:ost; consistent characteristic of' the she.1low groundi.rater chemistry is its apparent haphazardness" d.ete,ils of' the che:.a.ical system a.re poorly understood.. :r-:ow·- :.~elation to the chemistry of the deep ,grou:'ldwater.

S0apage Contributions to the Valley Fill Sediment

The purpose of this section is to provide a rudi-

rr:en-ca:r;y- analysis or the relative relationships of various

saepage contributions to the shallow groundwater system.

3ee"tJa~e :frorn. the streo.rn che.. nneJ_ at hiR~h stafre

t·ihen the level of water in a .cha.nzi.el is above the

g:rour~dwate:c· table the potential gradient is reversed and

·wa te:r moves f':rom the chari_ne 1 into the sediment• resulting

in mou:.1di::.-ig of ·wa. te:r adja.ce1'lt to the stream. This con

t:~ibution to groundwater ls called bank storage. During

the flood wave recession the gradient is again reversed

a.rod water in bank storage is released to the stream. A

result of ba:nk storage. in a stream having highly permeable

ba::-1k sediment i can be a smoothing of the flood peal::~

Evida:nce of bank storage along the Little Ivrissouri

River is the dil~tion of the shallow groundwater chemistry

by seepage from the river (fig. J8) and the slight increases

il:. grow... dwater head duri?'..g the passage of a :t'lood wave.

The channel bottom of the Little Missouri River consists

G:cavelly sand Ol" sa::i.d.y ,gravel are the :p:~e.c.o::1ina te

sedi;;i:,2:;nt types below char.n0l level. The sedimer:t :-,.z.s a.

:.~e1a ti vely high hydraulic conductivity. 116

sedir.:.e11.t loctd d·i1J.:·i:1.g flood s~2... ge. Sa::nples collected at

flood. stage and a.llovred to settle for an extended period .. can ];;ave a mud slurry which is about one-third or more of the volurn.e of the sample. Values of suspended sediment

exceeding 25,000 ppm i;,rere reported by the u. s. Geological Survey (1956, p. 222). As a result of this abundant sus pended sediment a ~ud seal (Harrison and Clayton, 1970,

p. 223) is formed on the channel bottom and banJrn when the stream is losing water to groundwater storage. T·he seal is effective in reducing the amount of water that can move

into banlc storage. The amount of bank storage for a given flood depends on many factors, such as the stage height and length of

a flood •. the position of the water table prior to the flood,

and the effect of the mud seal. ::i:,'.",filtrf'.t1on throui::th ephemeral stream channels

The vast majority of tributaries of the Little Mis so1.:.Xi River are ephemeral arroyos with channel bottom ';-Jidths ra.:n.ging from. a few feet to a few tens of feet. The

cl'iannel bottom sediment is predomi:r..antly sandy gravel with accumulations of silt and clay in the pore spaces. Streams

or this type typically have large losses of water as a

resu:t of infiltration (Babcock and Cushing, 1942; Qashu

and Euo 1, . 1967) • R":.:t.~off in these streams, result from

the typical higl-: intensity and short duration sumr;";~::· rains

of ·western North Dakot&, shows a rapid peak and recession. 117

The arno-u.1.Lt of· inf il tra:Cion ~nay be highly variable

on such fac to:cs e.s channel shape 1 sedinent type, the na.tu.:re and :..~ate of su:r·:face flow, antecedent moisture conditions, a:nd the a::.:;.ount of sus~Jended sedLnent. Infiltrometer measurements were made in two channels using a si:r1,c3le piece of thick-walled, 8-inch casing which had a cutting edge. The most difficult part of obtaining measuremants was carrying the instrument. However, less sturdy tubes would not withstand being driven li· to 2 i'eet

L1to the channel bottom. A constant head of 1 foot was rr.:.ai11tc.L1ed. d:ul"ing the period of measurement. TcG iltration rate was determined from the slope of' the cumulative infiltration (fig. 4.3). Johnson (196.3) d.escribsd the apparatus and methods used in determining infiltration :rates and discussed the large number of factors that effect ir..:tiltration~ He notes (p. 15) that, as a :::-esult of the many factors involved, a :particular rate for a given sediment type is nvirtually nonexistentn.

'T"""l .J..J.. general two rates of infiltration for the channel sedim.znt ·v.rere found, very fast and very slow. Very slow

::::·ates were controlled by low permeability layers. These le.ye:."s ;;1ere encountered at various depths in about one- ct the measurementsQ They are relat2:d. to a.rea.s of

on the char..nel bottom towa:rd the end. of a :.~1.mof f

:oca.. J.. ~ni·11--:;1-ation :eates. 118

Q l i r l I , Q I r O. 5~ L I J I I I ! /0 r ,::: " ~ ~: 1J fcq , µ.. I t z Ow 4i H

~ 0 l H 0 8 / I-, E--,; 1-l <; I / ;~ 0,.2-1 ::::i,.·""'i pf~ v J 0 I •i ..,I t I 0 -1 O .1 -! !0 0 5 10 1.5 TIME IN MINUTES

r1:

7 ~ igu:::.".a 4J.,--Cumulative in!"'iltration as a function of time. il'crs:cio:--. rc.tos for tests not encountering a low

• n Q 1 2 1Jer1:1eabili t;/ r l~\:irl[:;ea. I 1~0:,-n v ""-X .... 0- .i.·~/1.1_•.nv .. ~o.., 7 ·X. ir.J-J- su:.1ing th,:;.t local lo1i·1 permeability layers occupy an area eq_u:.valent to one-fourth of the cha.:nnel bottom, the ave-:rage 2 ra ·ce' 01:., er.-.... :i: ec t·1. ve 1n1· ... i~· 1 -era· ·::;ion· · ~\l'OU-1 d 'oe ·_=:-:a·uced, '= to J X 10- ft/min. A thin layer of mud-cracked sediment covers the bottom of all ephemeral cha.:i.'1:.tl.els during dry periods and probably represents a mud seal that was formed during :ru..""l off. This condition was not introduced in the infiltTo meter tests. Even though this thin seal is probably only slightly pe::cmeable, very large gradients are induced across it duTing peTiods of r'Llnoff so that significant quantities of water may move through it. P.:n effective infiltration rate of 1 X 10-2 ft/min may therefore be a. reasor..a.ble sstimate for the ephemeral streams of western North Dakota. Hagmaier (1970) arrived at a value of approximately 25 miles of stream cha1~~el length/mi2 of area borderir.ig

-the Little Hissouri River. This value was determined from the asrial photos of a tributary basin near the center of -~his study a:r-ea.8 A chan:t1el width of 5 feet is a reasonable average value {Hagmaier, 1970? rroral communication 11 ) for ttis basin .. There is therefore, about 7 X 105 ft2 of 2 cha:i."'.!l"lel bottom./rn.i bordering the river ..

:J and of' 1 hour duration {a reaso:"18.ble estimate tor a

-i -~·."'.""' "-h,..,,._ ... - ..4..--\..I•.,. ..;..i:.,,.,,.._.;,.,J.,.,,,.c.1·".i·"'arJ..·) - J.."ndi·ca~-,.,s \,,i'\;,, L,,1,,..,;;:;;.,. V V.\.J.,.,..e to+-:e,..,J..v~ recharge may be 120 ,.. J 2 ..,., >,o-- ,- h X i uri) f' -·- j~,, .J..· '-"' ,..1 L<.v -r -- - V .!.....i. or a oo·: ..:::c 2 pex·cent o:f the total

:""'err:.aind.e:;.~ moves longitudinally dotm the t:ribut.s.ry valley fill and is added to the shallow groundwater storage of ·chz Little Nissouri valley.

Values o:f recharge associated with intiltra.tion through

the e.:phe:a1e::ca.l stream channels may vary by several orders of Iri.agnitude for a given runoff period depending on a large nu.:r::lber o:"' conditions. However, the approximation presented hare indicates that a large quantity of' rec.b.a.rge to both shallow and deep groundwater may be through the bed of ephemeral streams.

Seep:1.rce co::r:::::cibutions f::com deep p.;roundwate::c The seepase contribution from the regional f'low system

·co the valley fill sediment could be accurately calculated it values of hydraulic conductivity were known for the predomin...:;-~tely poorly permeable sediment unde::clyinz the valley fill. Values of hyd::caulic conductivity for the d.ee:pe::c, :more permeable sediment~s ( such as basal Tongue Riv-er s&.:.""~d) are of :no use in estimating seepage contributions to

·che valley fill, because the rate is controlled by the ss perrr.eable overlying sediments .. If the ave::cage sedi-

-::~e1-;.t 1..::.nd..e:"'lying the -relley is composed p:rim~":rily of sll t s.r:.d clay ':hen an esti:me.te of the hydraulic cond:,:,c~ivity

2 1 t b""'- 1 -X 10- J.""'+:/n-,:;;y·_v - • c-r1e-""rc~-~~ en,~ "'9"8 0, '"'~- ~,,-:."'' s~·es.. _,

::;0:::1..sral values of hydra:0.lic conductivity ranging :t:com about 1.21 "' to 10-;, ·.{·t,/d.ay for rni;~t;u:ces of silt clay. hyd.ra.ulic can-

dir1g I'·Iot.mtE':..il~ Sl1ale il'l

Ca.:r.;2.da is G.bout 5 X 10-2 ft/day, o~ tritiru::: counts.

..:\pplying value 1 X 10-2 ft/day in y 1 s law for "' : ftL of area us a seepage gradien~ of 1.5 X 10-l ft/ft 2 yie a. ira.lue of seepa0e/ft which is 1.5 X 10-3 ft:3/day. The width of the :cegional discharge area has been st101•m to coincide approxi:w.ately to the width of the valley

:floor, which avc:r·age s tl:.i.ree-fourths of a mile. Summing the

&rwu:nt of see-oarro/ft2 over a 1 foot wide strip of valley f yields 6 ft) /day/ft of valley ler...gth or a·bout J X 104

Pt")ss 1 b}.e 1~e1ati ve o~crle-rs of rns.. g~1.i tu.. de

The calculations :presented above are understood to be only ss estimates involving many assumptions and un.-

;n1owns q They we:r-e m.e.de to point to areas of possible

evalu.a. t:.on ..

The dry weatheJ.." 11 low water discharge of' the Little :,,:12sour·i during s~"'llller and early fall~ averages s.bou.t 10 to 15 cfs at the Medora gaging station (sec. 27,

T ~ :L~o N. ~ R.. 102 t:J ~) ~ There is very little change in discharge for many tens of miles up or dowI1 the river· ..

s a;::;_om~t of 'base flow could probably be su::iplied entirely

recl"'.:.arge by infiltration throue;h ephe::::1e:ce..:. :;.22

p0:-c1i:Gaole valley :till sediment u..Y1d.er the river {as under-

tlo,;,r) and out; of the ·basine A base flow analysis of the

Little l~issouri River would therefore give only a minimal

i:1.dicatio:::1 o:f the total grou..'l'ldwater storage in the basin.

The exact order of importance c/ ·t.he three sources of

seepage to the valley rill sediment is unlmown. However, ·tan}:: storage is probably not as signif ica.nt a contributor as e.ither of the other two sources, and because seepage from the ::cegio:l'...al flow· system is continuous ~che probable

oTder is (1) seepage from the regional flow system 7 {2)

s.s:cpa0 e tr.i.rough the ·bed of ephemeral tributaries, and (J) seepage t;h1Aou.gh the stream banks at high stream stage.

::1ecr.a.rge to the regional flow groundwater system m.ay be prirr.arily controlled by infiltration through the beds

of low o:rdez· e:pheueral streams. CONCLUSICNS

Summary of Conclusions

The results of the study supporJ the following interpretations. (1) The Little Nissouri valley is the discharge area of a regional groundwater flow system.

(2) The discharge area is approximately the same width as the valley floor.

{J) The valley affects the groundwater potential at least down to the top of the Pierre Shale. at a depth of greater than 1,000 reet below the valley floor.

(4) The ratio of the vertical to longitudinal flow components (in terms of the gradient) is at least 100 in the discharge ar6a.

(5) The groundwater divides, in the center of the study area, are asymmetrically spaced and correspond approximately to the surface-water divides. (6) The western recharge area of the regional flow system has a higher potential and steeper gYadient than the eastern recharge area as a result of its higher eleva- tlon and overall lower permeability. 123 ( 7) Th,:: groundws.t0r chemistry is chc.r.s;.c terized by

.a sodium facies in the disc::-1arg2 arc&. c:.1-;.d bc:low a depth of about 200 feet in the recharge areas. (8) The domi~ant anions {either bicsrbonatc or sulfate) and the total dissolved solids show vertical and lataral variation. Much of the variation is attributable to a sequence of chemical reactions initiated by the reduction of sulfate. (9) The water chemistry re~lects several lithologic characteristics. (a) There is an abundance of soluble sulfate in the sediment of the recharge areas. (b) The sediment contains minerals with high cation-exchange capacity which are being altered from predominantly sodium-rich types to calcium-rich types in the recharge

{c) l11uch of the sediment is apparently devoid of soluble chlorides~ (d) A reduction in total dissolved solids alo::.--ig some flow paths reflects dia.genesis or" the eedimen~ by precipitation of dissolved constituents from g:-ound.wa.ter. (10) The probable order of importance ot seepage contributions to the valley-fill sediment is, (a) seepage from. the regior..al flow syste.m, (b) seepage th.rough the bottom of ephemeral tributary char.nels, and (c) seepage

Host of the groundwater i:n the vall..::y-:::... ::.11 sed.::::cnt leavas t.he basin as underflow. 12.5 ('.i.2) Othar more tentative conclusio::1s are suggested.

(a) :,:uch o'f: the recharge to the regional flow syst0m may be throug~ tho bods of low order ephe~eral streams. (b) Reduced chloride concentrations in so~e Ullits in the nor~tern end of the study area may be the result of flushing by an activ~ flow system associated with Pleistocene gla- ciors. (c) The Pierre Sha.le is a signif'icant groundwater- chei.:1is try boundary.

Usefulness of Present Groundwater Flow-System Models

Application of the physical concepts of existing :tlow-systetn mcd.0ls appears to be most useful in ground water studi~s in western North Dakota. The models can form a basis for maximizing quantitative interpretations fro2 a minimum of plan..~ed sampling. Tha cham.ical variables are more complex and a large deviation from a general mod.el may be expected. However, the variatim1 of groundwater facies can be reasonably c.xplained when considered in terms of a continuous flow system. .4.? P2}JD I CE S 1V1E'I'HOD3 OF DATA COLLECTION J... ND .P-..NALYSIS

lfJa ter Level .M:easurs,·1ents /

An accurate measurement of the static water surface in a well requires tr.cat two conditions be met. (1) Tha level measured must be assumed to indicate the potential s.t the bottom or the casing; that is~ the casing is not p0rforated and is sealed in the borehole so that no upward

can occur., (2) The level measured should be con- sta::..'.d:; fo:r the time of measurement (recovery :from pumping or:· .flowing of the well should be nearly complete) ,, dssurance that these conditions are satisfiad is sometimes slight, particula::'lY for vary old wells or wells "that we:ce poorly completed. ~.:any of the wells completed L'l recc~:.t y8ars in western North Dakota. are being cemented, which~ "v,rh.e:;.-i done with car~, should seal the ca.sing to the

bo:~ahole a::1.d eliminate upward lea.l{ageo Thzrefore 9 if the cer.o.ented and not rusted ·c~:roTigh. the

::· i:::-s-::: cor:d.it ion will be sa tis:fied. The saco~& co~d~tion

- - .,..., '-....·0,.,.,;;.J,. satisfied if suff!cient time is OW<:::d

_:r:atG 2:quilibrium conditions to be established and i:t' the:."e 127 128

teet a~ most)v for the values of total head used in this

·:r::e c.etc:rmina.tio:n of the water level in wells was

:a:~u.0 w·ith a:..1. electric water-level indicator (Soiltest,

1'!0C.8...L··• ' - .,....p.U-~- 7 0"o .d·. ) ., The total head was determined by sub- tra.ct:.ng the :measured. depth below the lar..d surface from

"c.:10 land.-s....:.rface elevation ..

The sta. tic pressure of water in flowi:1.g wells was t.cte:--r.:1i;10d using a bou:rd.011 gauge. The p1"e ssure reading was

co~1v0::cted to feet of water 11 and this amom11t was a.ddad to t~·-e J..e..11d su:rface eleve. tion to yield the total head,. Attach- i:·1g the gauge to e. casing that was constantly flowing pre- sen sor::1e 3n~oblems, particularly for high pressuJ:'e wells

\' (35 to 100 psi). The proble~ was solved by using a right e,:.::.glG pipe: with one end attached to a gauge and a packer The device was designed i:n such a way t::-.:.a\:; the ps.c1i::ers ·were interchar.gable:; so that pipes ranging t:r·o:c. 5/8-inch to 1!0 -inch could be sealed., T::.e packers were

:i_Je ~ Il the casing ·was nearly round a very tight seal • r 129

'\cker

~ r-,' ---- '-; -H ~ ~ -~'~'~-~~~~ -tj- - ~lNut \ -, • \__Connectirlg Pipe

F igu:;..~0 L:,LJ• ., --Schematic diagram of the pa.cke:r-gauge asser.1bly used to measure the watar pressure of flowing wells.

- 1111 :1.JO

c culd. be o Ota i::1ed C>

closa estimate o~ the potential. The amou...·1:C of shut-in time rs~ged from one half to several hours. When the gauge shoI•Jed. no detectable cb.ange in pressure with t.ime it ,·ms assumed that; sta. tic conditions had been reached.

Collection of Water Samples

Collec·;;ion of water sa;aples that a:-ce representative of' t::le sou:r-ce at the time of collec tio:n is essential if an inte:.~~::retc. -cio::.:. o:t· the chemical processes is to be u:'lde:r- Ex~ct procedures fox collecting different types of

·,:atei,. sarnples 1rary among investigators. The procedure

:.:'."ollm,;red. by the U. s. Geological Survey is outlined by

2.ainwater and. Tr1..atcher (1960)., The source of water sampled ::.n this study included spri11gs and seeps~ su:rf'ace -;,rater~

.s.:::d. g:c-ou...vid.vra ter (from . both flowing and nm1flowi:ng we.lls).

In this study the samples were collected in high density

polyeth;7le:a.e bottles with polyethylene-lined bakeli te

'I'he sa::nple bottles were rinsed several ti:nes '(.Jith ·;he 11ra.ter to be sampled before collect1on., The

tightly secured and

pl.as tic tape to insu:ce a." 1...,a.. s+-'i..r..:....t23 · sea_:..· - a.:;1.r.1.11t!· · 1J1

The gres.t;est nw.:1ber oz" surface-water sa=:ples we:-e

station at i1edoTa, f.Jcrth Da}:ota under varying states of discharge and suspended-sedillient co1-:c8::1tratio~1.. An attempt was ma.de to sample ne£.:.r the cante:.~ of' flow; howeve;.~, this was impossible at high stage.

Sanples containing abu.... ">1da.nt suspended. sediment were allowed

to settle 7 and the clear water was p:;.petted into fresh

G:round.wa te1~ samples ca.r;ie from three kinds of' wells:

s1::allo~·;r sample wells (cased, hand-augered wells a few feet d.aep)~ pumped wellsg and flowing wells. In each case the collection methods varied slightly a_ The shallow wells were installed in valley-f'ill sediment r."'or the purpose of collecting water samples. Sam-

:::iles ·were collected by lowering a. device to the bottom of

the casir.g, tripping a. stopper, and allowing it to fill. l-:any of the pumped ·wells a.re in excess of 150 feet deep~ some were several hundred feet deep. This situation ~Jrese:'lts 'che possibility of a. considerable a.mount of .stagr;ant water being present in the ca.sing if the well

h2.d not been pu.mped for a period o'f: timeg In this case

tf'ie -,~·ell was pumped until the casing was c:.2.2.::-ed of stagnant

HUtc::r· be:::"ore tte sample was collected.

suT~sce and flowed continuously. This eliminated the 132

,;·;·:;.ic~'1 i:.1.t;:coduced ail." i;:::Go the sample. 'I[iis undesirable situation was avoided where possible by cho}ring dm·m the

Analysis of Water Samples

All m2.jor chemical constituents, pH, and specific c;ond.uctance of J09 samples ·were determined as a pa:rt of t;.1is study. Other chemical analyses obtained from the North ;)akota State Department of Health and the u. s. Geological Survey {a1.1alysis by the North Dakota State Water Coiilillission) were evaluated. The following discussion of methods pertains only to those samples tr.at I analyzed. The method of analysis during the fi:rst field season (1967) followed procedures recommended by Hach Chemical Sodium and potassium values were calcula·ced for these samples; therefore less emphasis ls placed on their accuxacy.,

During the field season of 1968 some constituents ,I· ·were analyzed in the :field s.t the time of collection in a:.-: a:;::;tem.pt to determine if the wa te:r chemistry had a.l tered

o:."8.. "cor·y., F ielcl analysis was abandoned bece..us:e : t :·:as ti.::a co~stL~ing and the working conditions were ~cor~ .. s..na::::,tical procedures maintain their accuracy only within

C o~ the field and labo~atcry a:1.alyses indicated that no significant changes occu:rred. during transpo:r·c. The followir....;:; procedures e.re desc:ribed in the order which the samples were analyzed. Estimates of repro- ducibility were de-termined by duplicate analyses of' about 15 percent of the samples.

The pH was measured in the laboratory with a Beckrna.n Zerornatic pE r.1eter. The instrument was standardized with a buffer solution of pH 7.0 and checked. frequent;ly with b~ffered solutions of pli 5.0 and 10.0$ All solutions were temperature corrected.Q The readings were reproducible to

l·'.:easurements at the time of collection !'Jere rcade with a Beckr'aan model 180 portable pH metero The instrument was standardized against a buffer solution prior to each measurement .. A check against the zeroma.tic indicated that this instrUlilent gave relatively stable results i:f standard ized before ~a.ch measurement. No significant change in the pH of the solution was a.ssu..rned if the va:."'iation bet't'reen :::'ield and laborato::cy measurements was within !0 • .3 pH ur.1.J.t. A v2;.:cie.tio11 large::- ·cha.n this value occur:rei o:.'lly fox a. few samp:es~ ~his discrepancy might, in some cases, be the

tl1.s pH of those I~· ieLa. ~ - samp1 es not being ,,'C:'.c.su.rcd. ,1ncie:r st;ntic conditions. ~ap~od~cible streaming potential corr0sponding to -0.10

:;;E u;.:.i:cs at a water velocity of 1 ft pe::c sec.

Alt:a.linity, a.s used in wate:;.."" chemistry, refers to ·..:;he cs,p.9..city of a water 'co neutralize strong acids to p5: L:-.5 (Rainwater and Tb..z.tcher, 1960, Pe 93) .. Tt'.i.e deter- rrriY'..a.tion was made by titrating a 50.0 ml sample with a The relative amounts of car- oonate a:ncl bica:r·bo:nate were determined from the titration. Tne end points of the titration were taken as pE 8.2

(carbonate) ar1d. pH 4~5 (bicarbonate) following the pro cedu:re of Rainwater and Thatcher (1964, p., 94), who indi- c.ate that these pH values a.re the inflection points on a g:;..~aph of a titration of Nazco3 with. H2 SOi.,!.Q This should have given good results for the predorni:'latly sodium- bicarbonate groundwate1~ :::":rem deep sources» 'but m;ay have ~n~?oduced an error in samples containing considerable ar:io..:cn:cs of othe:r· constituents .. The values for total ssl}mlinity as Caco3 were reproducible to within 2 percent.

Calci1X11 and magnesium in solution impart the property

Oc,lled J:12.:cd.ness., The determi:r...a. tions were made by ti tratlon using a standard solution called Eexa Ver {P~1ch Chemical

--r'~ict,..,,._ n is" "Cna'1 na.ne give to a G~02 :: t:cJ_utior::. ot

1 "'O.~d ,. 8 u \c,. :.ng .1.\ KOE:) and. -·· -.,. ,·, ·--- ~.- .~ .. '. - ... .,..~ -· -. ·~'...:.. \,,,' ""- ~.-~.. V _... _ _;,~-' .·· -~- ·. .,,, ·'"""

\ I •

co..]_c i"V.. ra accurate

-:'"1.,.....,.;: v_\,,., ..,_ on

J.~asul ts ppm r... or

-: !-, ~ ...... '· .;. ';)Vv j

...... -.- · .. , ...... -~' "

·- ' - M I •.·.-.!...-"I used. -,..,~ ~, ... ~ '""' ct: ...... """.;..,._ ;.;;, ,_,_, __" r;;.. v-

"'! r,--·.;"' "'"'· ~"'- - r vi~-·- ... J~·~_ ...... ;.._,j J •

co::1cl: ..Gions"

s d0t;z;;r~11inat;io:..1 rDay be ord(;!r

:flame,. A

Sodiu::c. sa:nple was plac

~- ,.. ;:; ~:'• -..:.~ ...... l..

..~- ,- ,t: ~--: ,.r;,~..;..::_~' ~ ;: "':"!"-_,.. , ,.._ ,_ ~..:.... IJ~ ·~-·_._,

..::, ,---~ - . ~ ·~· .....;._,,,_. .._, . •..,1..;., V -,..· ~'-.. ...-,- ..

c,f.'

r:: c-cc:::.s ..),.

T~e largest deviation to be ex-

fo:.~ ::·op1"0G.l,1.c ibili ty is

lica. conco1:tra ..Cici.1s "£-Jere deterrnined !'.Yi tl'l the Fisher II, ~od.el 81)

silicornoly·bda:ce sodit=.ID. sulfite 62.5 to 675 mu)

:":con. a calib::cation curva d.eriYGd from standard

j,,... C prod1...1c i ·01 e

-- "' _, vV ..:..,,v.):) ::Jl:)Iil~ ,-- ,.,.._ l;: "" '.J:. -

.. ; -? ~~- ',. -- ~ - . ~ .,:_ - ... ..,,t_;__ ,_:._-'-"Cj_O~

-, - - "'! - - ~

• --~""'-""~' V •,.,),

·coher {1960,

t:.:..o:: ..,cc

sample

had

~·-"t'":""'..... -"1. v~..i...... '.,;..:(;..,S

.:. ..,..,

·-l, ui:-

.:.. V

iOYl3o a~alytical ex~or. Va.lv.0 s for pe:ccent-..:;r:ror were deter-

:ai:ned by

Elevation Dete:.:mi11.a tio:ns

only r.1aps 01100D.pas s entire area

The Little riiis sou:."'i HiVer has been the souther~ bo~~er of the SoU

.-~, ,l'.. ";""" ·:~ .·~. ":,..,, r-; ... r, .-~ ,,.._ ~·".\ - - ...,;r,M .. ._.... _.:;i .J...1...... ,C VJ. r> , ~ _: ...... -0 ,.. {l.,-,,, _...... :...... ,-._

control stat;ions

30ca:t:..se the of vo~tic~l. v~riationz fro~ ona site to

about; o::::e

Tl:1e

obtai11cd r::.:CS"i; sam.-

Loca ticn Foi~~~c

::.c

---:i .... ~ •., .....:;...... :_ I,.,.,•, .,_ M<'.' ... ' --.. <.n;~:,:,. ,,,,.,...~-V ,:,. -·;.. ..,., ,,.,. ) "

._,._ ~ - .,,..~ .. -, _": ..,,.. •M~• >-v..~.- _...,., - '..i - --~..;.,.J:;

sec. 26,

102 is i~ s cy the

02-26cba.~ 1! ii :;..._..-,47-62-loooo u

l!·.5v=·~2:ii2.g::2.r.i j_llust::r·.s.::ing the: location torma.t~ :re~ 7ra~? {1963, P~5). s ~he cross sect~on

1 /"\ \ .J. \.) J u

t;o

iv~te wall drillers. A

of t.r.1.e s. Survey at

., ... ,.... ·,· '-'J':...'lo' 11.}0-102-11c~dd

2265

Der:/:h (f(=;et)

Alluvium: 1 ,, ,: ;:_ ~&~ty clsy------.... .) .:....,1 G1..... ::.:.. ...ve ------10 25

ji'ox1::;ue Bi ver }7'01'"*rnfltio1.1.:: r:: r:: b:.c:.::dy C lay----u------JO _,_,) Co~l------5 60 s~ndy 10 70 clsy------7-:; Lime st;one------) ,..,I "l ~ ,, GTay clay------82 ... ):J Streaks of s~nd------50 205 u110..1.e------("'t) -"! 35 240 18 258 Coal------I, Sh~le------ ...,. 262 1 26J Shale~Coal------gray------2 265 Coal------.,_'I 266 Sh~le, sundy----~------9 2?5 Coal------6 281 Shale, sand streaks------300 19~· Eo..1.,.d. shell------...;---- J. J01 6 307 Shale,a------light g~ay------17 J24 4 328 Sh~le~Ccul------~------greenish------12 JL:,O 4 344 Sc~Q------~------ "'.) Sh~le------ ..) JL~7 Sand------~-----~ 3 350 Sh~le------ 15 J65 J J68 \ Coal------ 7 375 \ Shale------~•------• 45 420 SandySand------shale------4.5 424 .. 5 11.;,0-l C2-10bdd

ElGV.:

.;.. ~he well w~s o=is~na~~Y tri 1 to 825 v and later deep.8ne6. to 12.33 x"ee~~.

Tl'1iOJ{l1e ss

No record------82.5. 825 Ca~nonball FoT~ation: .:.3ar:.ds~t;one------830

~udloii Forrr!at;io?.t.! Do.rJr sha.le with thi:.1. coal st~eaks------59 889 Hell Cxeel::: Fo::cr:Iatio:r.:.:: Sand?ock------~------14, 903 Dar~ sh3le------142 :!.045 Sst.l."':!.cir·ock------10 1055 shale------90 1145 Light; sanely shale------J2 1177 Fox Hills ::?crma"cion: 'l ... s::~i1d.------· .J..!. 1188 Da.1... lr sliale------ 8 1196 Sand------~------37 12JJ ~lllt1vium: Sur~~ce soil------Gr~y clay------11 Yellow clsy------.,1, sc~r1d 8.:r1d e;:ro.. ,lel------1... _,;.: Tongue For:r:1~t;io:.1: Yellow cley------ 34 't'~ hi. ~ce sn:1.d.------ 38 ·.St;.ndstone; r~St:cd.------L~O 51 cl~y------ .52 Cc~l------Cz .. ~·t,on8..ceous s}1ale------2 54 . Gl""C:.:..';/ sc~:"ld.------ 86 140 Snndy cl~y------ 8 148 D2rk cl2y------~------ 4 -../-'1 ~? Cc.::~1~ ti .r.:...;..:.:"'lla.------JO 182 \:j l"°!i t;e so2.psT;o:::e------26 208 cl&Y------11 219 iii~~ht rsi,..ay cl2..y------19 238 ,... /' clsy------.:;;o 291.i, loose fine sana------26 320 sahdy clay------10 3JO Ludloi,1 For:::o.. t; io11: 5 s~~iy cl&y------ 15 BlU·S ClCky------ 11 i.S2Y.:cly c1.ay------26 ~5 c_ay------15 Sa::i{~s-cone ~ l'12..1.'*d.------2 21ue clay------L~1 Sc:.:::d..y blue claJ.r---.------11 3lue clay, hard------18 8cndy clay------4

82:r~Cs·C:oT..:.·e---.------2 10 ,.., . .) ·'·

~~~o olay------r :)z·,.:.~1: cl,;_;,y, hc~1~.:t------I 3oapsto~e------8 Co~l------2 I1~~~s sa:1.C.., hard------31 Fine sandy cl~y------35 140-102-26bbo, continued

Tl1!0Y:11ess I)e 1:;tl:1 Source Litholo~y (feet) (-,"se,c)

L udlov-1 Folnom;:it; ion: 7 613 s~ndstone------Coal------2 615 Gray clc..y------2 617 Scapstone1 hard------53 670 Cannonball tion: Quic1tse..:'1d.------ 1_o ,, 686 Stone 1 hard------ 3 689 Fine sand------26 715 Ludlow Form~tion (?): Co~l------2 717 So~pstone------9 726 Coal------4 730 Blue clay------ 10 740 Coul------4 744 Hell Cree}:;: Fo:r-:nation ('t'): Dark clay------ 26 770 Co~l------ 4 774 Blue cl~y------~------JO 804 Coal------5 809 .:. Elue clay------~------..J 814 Coal------8 822 Soapstone, hard------38 860 4 864 Coal------.., ,, D~rk shale, ha~d---~------.1.0 880 Co~l------~- 10 890 Dark clay, hard------ 50 940 Fine sand and sandstone------22 962 c; Blue clay------_.,; 967 B:rmr:n. shs.le, carbonaceous------8 975 Coal------2 9?7 Soft sna~e------ 41 1018 fiaxd shale------22 1040 :?ox Rills Formation: Soft~ fine silty sand------69 1109 140-102-26cbb

3lev.: 2276

Com:::ient: The log of this well ( 1 92 9 , p • 7 8 ) • Thickness J:ept,h Source ~ithclo~y (feet) (f,2et}

Alluvium: Sand------JO JO Tongue River Formation: Coal------7--- 1 31 Soapstone------44 75 Coal------0.5 75.5 Soapstone and sand------47.5 123 Coul------23.5 1L}6. 5 Soapstone and sand------J9.5 186 Quicksand------85 271 Ludlow Formc~tion: Soapstone------5 276 Coal------~------2.5 2?8.5 3o~pstone and s~ndstone------85.5 J64 Coal------7.5 371.5 Ss.ndstone and sh&le------22.5 J94 Coal------~-- 2 396 Soa.ps ...cone and sa1.1.dst;o:J.e------18 41L:- ss:.nd.1,,oclr------5 l.~19 So.c:.pstone------24 443 ..,".\ 446 Soapstone------~-~------Co.c:.1------ 38 J..J-84 Coal--~------2 486 Soapstone------~------ 12 498 Coal------~------2 500 Cannonball Fo:rm&'.tion: Soapstone------14 511-~ Iia.1.-sd sei.ndroc]c------5 519 Fossil shells, soapstone, and sandstone------~------50 569 Quicksand------35 604 Ludlow Formation: Co~l------2 606 ; Soapstone------,, 609 Coal------_,"' 614 Soapstone------.,,...,,:; c; 669 140-102-26cbb, Continue&

(feet)

So~pstone with fcssil------2 671 ~u.:.cJcsc.:.--::.d------l. 8 689

"'--~.. ·m,,+ '1.· Lud.low .l V- -4--'-"' V - o·rl.J. {\ ':')• • SoQpstone------ 72 7c.-1v,;;. Co~l------5 766

8l..J,4 Sonpsto~e------ 78~. .) 8L't7 Co~l------~------', t:. Sonpztone------.,JJ 882 Co~l------1 883 '

1J9-10:i-10ccc. :Slev. : 2595

C cr.o.msnt;: The log or this well is from Sinpson ( 192 9, p. 7 8) •

'I hi c lme s s De":!th

Li ~chclo-~y (-,."'ce·-)\ ..!. V .,. L, (f'~et) Sentinel Butte FoTm~tion: .56 56 Sh&le------ ~ r:7 Co~l------.J.. .I, Shale------29 86 To:ague River l7 orrna tion: " Coal------~ ...!. .G 98 1Lr8 246 Sha~e------,,.....,, ..., ? ....-ioc~-:------.I 249 ~~ J Sh~le------64 )J.. Ccsl------9 J22 Sh~le----~------99 421 Sand and shale------135 556 Ludlow Formation {?): 2L;, .580 Rock------6 ,586 Send and shale------45 6.31

,I. f11 139-99-21ccc

O',., ) Elev.: 2620 This lo~ cont~ tentative p!c for t;}1e :3e:.-rti::.el E/u.tt;e-·::onf~.ue Rive:... 11'0::--it;ue Ri-r...rer-Lud.lo~·r co:c:t;~ct;5:Q These ~'Jic}rs ,:,rere e..greed. 1,·rit;h and l.~1.corporat;ed. in~o the cross sactiono The top of the cc~::1:ao:rJ.ball Fo:cE1s.. tion 1·re..s ~"lot i1.aidice.:Ced on the logv That pick is solely the responsibility of the writer. rrhic1:ness De~oth (feet) (feet)

Se:a.t;i11el Eut;te ?orrnc~tion: ·:;:'o~osoil? dn:rk yellowish gray, -vej,,_~y :1:,., ine sandy loSt.m------1 1 ' yellowish r;;ray to dusky ~te=:.lotI ~·Ji th iron st;nins t.o

b2~01~:"::is}-1 gJ}o.. y ~ silty~ soft 9 oxidited------19 20 6 26 8/_::..le te------, l i:':~ht to med.i ur;1. e;:::·o..y and brownish-blacki silty, c~rbcn~ceoust smooth, tight---- 14 40 ' ligh~ gray to light [Sl'*ee!1.l.sh rsr~y tii ~h Oroitin stains, silty------~------10 50 Sh2,le. :moderate de.rk greenish sr:ny, s&ndy------9 59 s~ndstc~e. dark greenish gray r::.r.. d bI·o,:,rnish black. fine. clc.yey, c~rbon~ceous in part, soft------9 68 3c~nd..stone, da~~Jr gxeenish gray 1 t·i.ne s.nd medium, contains l te flakesi fairly clean, .... ·:\rec.1:ly consolidated.------ .L .!. 79 Ss.. :"!.dst:vr1e, gree11ish grsy 7 .:11clu!"a "C;eG.------2 81

:32,nd.stona 9 d.arlr greenish gTay,

f i::"le medium 1 weal{ly consolidnted------~---- 7 88 .31:ale, white, sandy, clayey, ,.. soft------£.. 90 5.'.:;,:J.C:.S'cO::.-:e, 2cS clDOVe, taJrns .~ -, . ~luid------98 ------2 100 ~ te. blz.ck and brom1, soft ... ,, .... ;I tal~es drilli11.g; lluid-- 15 ~ J.. .J ' ~ight greenish g~uy, sil·t;y, srnootht moderat;ely l:L":rd-- ..,c; 120 .. 139-99-21. CCC~ Co:.::t i:'lUed. Th!c~nass pth

Ser:.tinel Con tl.1:11-2:d: t,.,.· l~.".';> 1 ·:'.:.I UJ._.._._e,;? to F~l""C~";.l ~ s 1\r~ t;l"'l tt1i:"l j_t::..yers o::"' ~.ql~i te on!tio clay------20 lL~O 10 150 g~~y------10 160

18 178 Siltstone------(?), yellowish-gray, l1ir;l"".:ly calca:;_~eous ~ ind:1.:-...r.a~ted--- 1 179

S~12le 1• m·edi u.in g1~a.:,;r, bentor1i tic-- 9 180 1 te------.L. 189 bl"lc~le ~ r~s &:..oov0------ 11 200 ' interbedded med~i.lill gray, silty. c,nd. dr.,.:r·}{ g:r·eenish gr·ay, , c;,1.nd v""J:li t:e so:t'-t; clay------14 21LI- s~one ~ gTeenish gray~ i1"1d.t1r·at;cd-.------ 3 217 Shale, greenish g~ay and medium gr~y~ silty------ 9 226 Shale1 g~eenish gray &nd mediu~ gray~ bentonitic------10 2-:i"".,,o

Tongue Rivel" Formation: 9 245 Shale~ me&iu~ gray, t • with ~hin interbeds of yellowish buSI... slj_gi1.t;l~y calca:-..eous sil·t sto1"J.e o:.~ i:n.dt1~~a ted bento11i ts--- 12 2 ..,~? . cerbonaceous------ L~ 261 Shalei ~edit:tm gray, silty------ 10 271 Shale, bro't·mish blao):, cnrD0~1aceous------5 276 ;ll Ligni te------~-- 3 279 ':11 Shale, light; gx~y, var;/ sil·Cy-- 4 283 Sc..r-1.d.stor~·e, lig.h:t; grs~Y i ve:cy fine, '=<~ semiconsoli~ated------.,) 337 , sandy------L:., 341 ·co}:'.!.e ~ e..s abo"'Ve ~ some- bu..tc ,..., w~~t claysy------C: .365

Sa11.d.s.:co11.e ~ lj_1-~r.i.t; oli""le g~ay, very :t~i11e ~vo fi:.:1,a ~ cleu..:r.:.e11

·tl1.art above j se::1iconsolid~ted---- 2L~ 389 A ~ S1"1s..le, sr-ind.y-.------· _' _, ... L;,cz

II 139-09-21ccc, Ccn~inued

6 L}G3 '? ssndy------.,) Li,:1 l t g~2enish-gray to very fins, clayey, 8 Ln9 ~, ------.) l•?'.,-r~- ss nbove------J 1~25 s&ndy------J 428 sandy~ 6 4Jl} ') ..) 437 3 440 l , silty, tic------~~--- 5 44.5 4 Lt49 sil~y------2,, 451 Silts~cne, as acovG------0 457 te------2 459 i • sandy~ sc~::-.1.C:st;or.:.e QS--~--~------10 469 , 1 i~-.:;-e gi.-.ay ~ sil·t -;:;o t·i:::..e!I semlco~1Solid,e. t:ed-- 9- L~78 li3!11.jc r;:_~:::~y.. :; s ~c~1, ·tir:1;ht 7 485 o ligt_-t g:t:.~E:.. y: SB.. Y:i.dy, clc..s~ey ~ soft------8 493 S~:~16:.2 lig~t olive gray, ,f."'l." ._... ,.,., ..:.. _:_..,..;..v., ...... _.. co~sol!~ated------ 22 :;).!.. :; Sil~~s-co:;::e, li.gjlr1t is:.~c.~-:l :J very Y, so 7 522 v------Q as above, lignitic--- V 530 ~:,.:.r:le p sc~nG.y------..,i 5".) ;)~ 3:l"cstor.;.e i l t; oli~ve grey~ ve:":.y sc.nd.y; sor...... C------15 548

L1.-:d.low tiOl"l: ty to sand.y------5 55L;- ·~e------:?~ 556 She.le 1 silty to S£,1:.d.y------,.,I 559

.s:.:""J.d.. ~; ..!c gr~~r ~ s2..r.1.C.. y 30.f'wt, v;i ~th :i_.-i.beds of silt;y i .. :.~.1.cL loc:::.lly cc.:.1 bonaceous shale------19 578 1J9-99-2J.ccc 'J Coi-J.~;1~ued

·I'hic !·:~"less :::~.::::-et)

42 2ec~vered 10 feet of 3 t-;ic ---~------~------1.0 630 be~ded ~s a~ove------12 642 Sl1.~-:.J~e:1 l t to med.l~11·grayw s:lty, smooth, t ht, with OCC£:.S iOT.'..Cil i.ta:rd dl,a illii'lE;------ 12 to:.;.8,, lir5ht: 31.... e:.~r, t:cco;;qi'lish [;r:c.. )', s:-.i.d. 2;ree:t15-sh 31'""0.. y ~ silt to very fine, clayey, soft------10 ------3 tc------.3 s::['~]~e ) ous------4 :S}1.:,-,.1e ~ sz,nd.;y------4 Si~~stone. greeiish , sandy, I1os~~1y so:c"'t., :ivi t;l"1 ~cl1.i:r.?. inC..u:r.. o:ted l2YGTS------7 685 S~1~l8 'I silt;y and se~::-1dy------13 698 Sil~stone. as above, inter- d -v;i tl1. ve2~:/ :f' i~1e soI~t; s.:::·.. 2:cts~~one ar1.d sc-;.Y!dy sl1a2.e------20 718 J 721 Sil~stona. i grey, clayey~ ~ ii1tor-bedC.ed t.

C~·:::_~ S S r: 2: ;;~~rl (:""'::;~·:;t~) { I"' r::; ,~ ~:: ) s::tsto~3~ as ~bova------ 2 B.,/c,C/ to Ct.:1"1.:iCYj/2C60U_s------i~on-ce~en~ed------9 S , gr~y. { poo:c S~'.}~}Jle :':CG"CUI~::1) ------ 891 Cl8.:fey: ind:u.r·a~;ed 8 899

14 913 ;:. -t-ve-----~------. '! 91L~ S2.... j."'J.G.y------7 921 ~y gTeanish gray, ve~y ~ignt, witb a few thin i~tsr0e~s------16 937 !?;1.-.C:~Jr t:.nd 8reeYJ.iSh 6J..·c:;... Y, ·:;ight------1.3 950

11111 tio:n

! ,~ ' \ \ ••••;:: ,j ,J....J~ w

p ,..,? v:::>-

0 Co .. ?dd. 5

,"'-,_...... i,.JV,.:i

- • [\) N r·~·; f\) [,) !,) ,.. -. ---..1 --.;) o, .r-,- \...,) N \..n ·r1'· CD N ln \() 0 \.T, '£1 G', ·,1 t- ,, "<"' co ' (• " . e ~ ~ ..

I·-~: ;·r1 ~,-:! I-·\ tT! i,-~ ~-···- :.i:; ~;/! ~-·· ~~ t-,.-~ f·] r>~ .... 1. p.:; I··~'- t~· ..r.. -c;; " -{-· ,~ C r:; b v.l ~ I..<) :Y 0 \...t) ~:.; 1-.' " td {:·· t:1 tiJ 0 tr1 i-· F~ bJ •' l,:J V'J tiJ · " j-L " " 1-' l,. .. i p Ii \[) I-\ I ' I-' I"' l·d 0 1,:j 0 1-(1 1-d $) (') •·ct 0 I [J 0 l·i) 0 () fl) h-J .. 'd 1~ I-'• ,,, I$ I (\) ,,. [\) t\) j---~ I\)(.> !\.) 1-'· () {'.) 0 l- N t-'•·f I-'· I·" !'v 0 I-"' !-" c·, ~· ,_,, r'' I-'' ,;,; I ((l \.J't I (fj \J1 t fi (l) •-,J t $.~ ([I ·...;! 1-'· f...J ([) . t-J 0 0) I (j) .. ,J i I·" n, er-. r I" e, f$ -...J \n I··' Ii \[) $) ,..i fj \..,l ,t:;· ::; I-~ l'v \rt ~·J (\.) 1-$ 0 I·' ~fl J·J i·' ($ l :;, 1··; CJ'\ f\) ! . , J., 0 ~1 N ll.l ,-:: ND'd· 1--j o,P• ci· ,-~ -.,.J (J 0 I-~ 1--·' 0 Ii N-,1 ,9 I) 0)0 () I~ en 1- · J·J (1) {\) 0 (I) 0 Ol p, (D [') 0 (l) 0 (!) er' <·i· (i) p I j (\l p () 0 0 I I .. ., t'i' l;j o·:.:; P•O CD Cf.J {/J (/J IJJ (fl 0 l/, 1-.•· to .. .. ,.., ., ...... , .... :::r " .,~ ,-.,- t.~f' I ~s I ,J ~.J .. ' f,) :·r p) h} "'"" fl) !~ I)) 0) .p fc) I .:;.:"I ~ " .... f..J f--1 f ' I-·' 1-• I-' !-J ~. I-' ~ I··' 0 f--' '' f•;;! (ii ([i (/j (1) (i) F• (D (1) .. ·. ,~ (;) (i> ·1"-·i '1:J r'' 5 0 m !'. ' .. I··' 0 . ~"'' • " 1.,.~1 ~ .. J t'°'i n l·d pj ;r~ I-'• 0 I l.:J <' p iT! t·j ~ " " ti 1•) 'd 0 \j l-'· t,j ::0 :::ti..: ~·) 0 0 ::-o • \f, • .. t-' 1--(1 oci =; I-'· I·.,, ~:) '° I-' (l) " :::; ca , ... Jt (1) 0 ~1 ::.:; (.'i' ;;;;, b:J "-r •. .. ..,. i::: I·-• ("1' ci' Ct> JJJ3-> ..:~i.ll-:;..;.,·~._:S~.:. 137-100-<:.. / I(o3o 291.S·

Fe~c:::.~01 w luk ill 141-99-6cb K-1E'1 2735 615 3746# Davis CoQ - Kevin Fed. #1 1J8-100-10cc KoB.- 28:4

Fie:.:-:re Si1ale 812 3761. Amarad2 ?etroleu.n::. Corp. - u. s. A. Hellickson Unit #1 139-102-2dd K'"• B ., -..1:)?".,""9

921

3797 ~ ..1me::.~ada ?etrola'U.17.l Corp. - U., S. A. Bruce ill 139-102-14ad lt~Bo 2370 ?ier~e Shale 9L!~ 5 .

3885 o iu:1e1~ad.s. ::?etroleum Co:cp.. - Scoria Unit /Jl O :J9-:i.01-9ad lLB. 2488 848

Fierra Shale 1015

Pierre S?rale 511

S"Cate !!1 'j:on Jo:r~ae~Yi - II - 14L~-100-Jodd X .. Bo 2597 159

1J8-~02--10G.a. B.. 2523 1098 Oil 13 [)-~ G~~ ~21.:--cib B. 27J2 r ie1~:r·e Shale 860

?e~roleum Corpo - Burkhardt #1 :;..39-102-8"'.::;o :3Q 2496

1028

9~ ll Oil Ca. " P .. -Govt;. //41./--14 14.L~-2. 02-1 l+C:d K.,B.. 2.341

4455. ll Di: Co~ - Govt. #41X-8 11~ 3-101-1 Saa B., 21-;~68 772 4642., _4..ill.2?~a(ia ?ari;J..~010 Corp., and Kewanee Oil Co .. - ·a~ :S..; ..i~~ Tract 1 #.1 :LL~0-102-3Cco B.. 2585 950

Count;, :nter1:s:. -tion2..l Nuclear Corp" - Lutz #1-6-21 "'':l"J.. ~l..-l "'O" )-oua o·. B,., 31.06

1920 ..

1589 ,. 1 0

-C,:~/'Y<·~-~·.c·,'"-~~1 t·:uclea1~ Co1"::i~ - I..e~·rtc:1 ,1)1-5-8 1J'l..i...:J..Oi.-!.9cc X.30 2932

·'- ::. v..::.. x~clear Co~P~ - Freitag #1-8-7 132-99-32c..d. 3~ 2904 ,-,// 1 .)vO

4L;.. 52. ·Cio::--~l. I\f11c:ea:r- Col.,..i)~ - Peterso~~ -12-20 1.32-105--27.ac l{.Bo 29:21 le 2606

~cic:-:s~l Nllclea:r Co:cpo - R. CG L\J~ez-1~e !/1-27-18 1J1-10J-25ba. 3., J046 1913·

1-JucJ.ea:i:· Corp .. - Gunvaldsen il-1:'.!.-22

2007 tio:.:8.l !

Sl~ale ., /'•' .;;_C,.l.

Corp.,

4517. =~~erns~ional Nuclear Corp. - Norem §1-49 1. 31-1 QL~-~: 3aa IC ... Bo 3182

4.. 51811 Int:e:,:-::;:;~ o::1al ?-JucJ..ear Corpo - fJ:oss brucker //1-47 132-1. 02-·-9&a l(oE~ 291+3 1643

.:;,-;:orial lt'··1 - 25 1.32-: 0 5~~~15c:a b., 2 989

2200

454,0.. L:';:;,e::,:•::s,·c:lonal Nucle4r Corp. - L,. Roen #1-48 132-101-32~b~b I{o3~ 2958 Shale 1598 I Nucle~r Corp. - Evans #1-46

1889

Q1mn County

89? .. T Q 'iJ ~ ba~1in //1

Pierre Shale 339 !408. Ca:ifornia Coo C,. Danielson & .Es.nk of N. D.. 1L~#8-97~20:Jc IC 3. 2162 429 I•. ,-· (\.) {') \{) --J ,_ -~ \.J1 .~;· -...:-~ (i, (\.) c, 0 Ci\ 0) --...1 I·' I-' 1--' \.;) ·--J V'I G\ 0 0 1--' t, .. \,J1 0 • • • . C ~

;::-~ ,, {/) i:-:1 l-1t !~:--~ I"·' (,) '" t;,: :-::~ I-\ LJ t;-:! t·! Q ~'":iJ J-..l. :11 p~ I-·-' (fJ ~ l,__,J b' e .(::·() ,, .t~ rj ,, J.-· J · I r-~ I ' 0 0 .. r:· f.:! . .{:· (il -t:--- ci- a 0 b·J \.0 {j) • tiJ \,,;.) l·J t'i1 \.,) 1-1 tu 6 r,, bJ \..0 f-' 1 (J, ([l I·' ~ t1J Ci\ 1-- t';J Vi , , t f .J ~ I c·I· C •··\\ Q I t 0 .. I 1-:.i ~ ., ,._., f-..J ,.. ,. tY i--.~- ~,::, • I i,J I ~~ I c:· I·' I·' $) () \() ; ,. •~o 0 ,-u C) ,0 r:> "',J 00 •,J o:; 'd 00 0, I; ll: 0, I J f1J I-" f'$ \.c) 0 I"'• {\) l,__,l l,> I·'• t,) \. ,) 1.. :, I-'• [\) \.J, 0 (\.) 'v.l ,, ,, •·u (.;~ :s (ll I·'' ,.... t·,:, I I·'· I·'• 1,__,J I t·;· I,, t'l.1 i {.) \.r1 i ~,, (\) .f::c i (f) \.JJ E , ..i (!) (1) rA o:i r 0 Vt I 1--' 0 .t:::-1,._..1 () CD 0 l',) 0 (/,\,.1) !.·.\ t J 0 \..,) !-' 1-·J "' [\) (i) ~J 0'-.\.J) (!'\ , __ , p, f;i Ii 1-·' tv lj \.cl (h;i" 1·1 \,__.) f L' l··J C) C~ fi \..,_) \.A 1--j 1-.:; ~j •-,,:j I\) l·J \.J1 o' 0 \J, Ii \J\ ,t::· 0 I·) \.rt() i-~j \.C.) (i.l 1 (I) 0 (I) '° p, r'' (1) (fl ·J $) C ro lll 0 f•) fv (l) f'.l 0 {D 0 \i) (!J {':· ((• fl) 0 0 P•O Ii ~\, f.) 0 1; t.1 ~~J (/J • (/) µ) (f.l cri p., [f., p, ' 't:i '"d 0 (/J {fJ () (I) •::t •:1~ ,.) ,-5' ,-.~ 0 . rs .. ~J~ , • 0 tY I·' I-'· io ~ ti'i fl) !i', ... ' ) 1--1 p p; ~ f-! f,.I pj 1-,,,"'• ~ '•:) p: I· I :J I··' I 1-,.I I f)J f .! ,_, ($ p. (l) 1-·' I-' rJ 0 (l) (,) (D Cq t-,t '-1j 00 '1:_1 (l) H I '1:.J r" ~..J " ~ .. , (I) p, • iJ I I-' () (1.' (h " [/l {I) I (I) 0 (',l l:,cJ b --,-~ 1--' 1-,, ~~ ~-, I·-' (}q '~ ~-;;~- ..... 0) a -· • z OJ (\.) SI) O'.) :::,· ~) \.;.) 'v.) t\.) \.,) .. j-A bj t) l ··' I-·' \.T'\ ~\ ...... d· \,Jl, tJ 0 I-" ~ I\) \.;.) .. , /\., t-· I,.;:,,> ~ .f::·P ~ ~r.:-· i'.J ( \.,.l (1) r< :s . ~ \..,J •--~ LJJ co ii t1j co ti b:I O f:.i lri !',) ,.; n.1 .,, n " \.Jj i·:! < \..,) :-:1 t\') trJ \{) tel (ti 0) ((l I ,. F• 1 t,1,0 b·i • I ' I • I ID t 1 ~ ~; t,.l 0) "' I·-!. ~-~~ J... ~. }1 1-'· I-~ • .. I " I IJ t I··', 0 I··'· I; I·' l· 1 ~·.) , .. , 1--'~-· l-·1 }') • 'cJ '-cl 0 •u 0 1,j 0 lli f--.) •· ,. rj ,.,, 0 () (1, 1 I··'' h) .::::- :n [\) \.,) ti::i I'' !\) IJ, ,.,. p, •rl o~<: 1,1 OP, I() C) f .1 (l) l\) .~:· l'J \.,) 0 f-:," N\..,.l (0 h) .(::· J.,, co I r: IJ, ['., I·•· {\) \..,) [') .. ,,, I\J } .~ !3 I; \.J \ ! cu 6 I··'' (/1 IJ, ! (0 (0 (i) O, 1\:1 ;3 I ,' Cl', I\) t·; \j.) !\) --J I 0 CO I o, ! } I·', ••, \.)\ 1., I·', \.rtl'O ;" J !\) ,,, Co (l',ci· Ii <·i· ,-; I·;( (i· o, ''·] o,,o •·cJ I ·' I ' .(D v, '° V-1 F· d· v, f\) t·} \.Ci I·:( U,\..,J J.. ·, p., (l) o· 1·:f 0\\..,) ,.. , ... p., ([) 0 CT> p.. I j ·s..:i D (!J ,., O, l '(P (!> o'O (,1 Q p. ··~ Q ! () I o' I p., l f.1, I ' (O o·' c:- (1) () (';·· (./J (fl 0 ~) CJ' 0 1-;I p! t~J lJJ en Cf.; (/J ::::t w t:r c• tY t1J • 0 (/j 0 (Jj () tu 0 p ( ;~ ·• t';i !:Y :~- 0 :-J_. 0 , •• J fl) C iJ~ f,, p:: rt fj- j-J ~1) .~ F.1 I fv C f0 f:) I· ' !--J I , )-1 (ll Pl (0 (l) (i· [;) s:: ti !·' I·-' ,.. , .. , (fl , J (l) cl· (I) (!> (i) i s:i I r1 (I) Q (I) (t) !:{ C (II ('i· I a, £1 (j) ,, 0 ~t> c-1· f-;j 0 :,, r):J " ., (D •·'·- .:;';; .. j (I) }~ led I ' ,.... ~\::_ ·d ~ 1-i 1-J .. c·I· I-' 1--'· fO ~~ (Tl t:J 1--' I··' ~)j (/) ~ C (!} a, VI ~;: I··•• !JJ ct .:;,.;: ' .... ~ ,- ... , !3 I'·• I··"' I-' I-' i-'""' \..,) ri ~i.:: 1-• ... u f:) \.,J \..,.} '-() I-' 0 !··' 0 I-·' 1, I ' ... ' 0 ,o I·-' ' \)'\ .,.) \.J'I \.,) .{-·... I·' \.ft ., ..l I' . C) Q) 0:l !" -'1 \.,J v, r- N \.,) ,:; o, ,- I·--' .. --0 '° °'r· \.,J .c u pi .. ~--' p. l·J 'i 1-; (} • ~ r~., ~·1...:i. ~n~on Di: Co. of C~lif .. - J :Llt<3-:i. 0\.. --2:. ~c l':~Eo 2L:,57

P ier:,..e Shale

1.~730. Ts.. :r-s\1t ()il Coo /JJ :i. !..:,i~-1 O3~1 7d.d. E .. B., 2391 ?ie1~:-ce She.. le 783

Tct.:r,?;et; Oil Coq R~ if5 1l;-5-103-9oc K.,B .. 2630

1? icr:ce Shale 68J

fl/ 473J~ Tarse~c O~J. Co" P., .....0 lfD 11.~2-103~~ 76.d ::<...,B., 2599 879 t Oil CoQ - N. P. Ra Ro J8 : l+ 3-10 5-

-..,i1 71.~..!.,• • • ..i.. Q !¥1ule c1~\seJ: 1 Coo - Shell Sta:Ce //1 140-103 odd 1{4l3G 2618 Pierre Shale 1043 Slocomb //1

Pie1... :::·e Sha.le 1165 0:1 Coflt - .. 9&a. 2c;10 850

7 • 33. ?et::rols~e:.m Co::riv :L:-9-95-::.2 K., :G.. 2lf38

529

JLtl" Sts:.nol Oil ar.:.d. Gas - '.'i ood:\"ard Starr //1 152-94-2'.:.cd :i:~ Bo 214.-0

Pierre S~.i.tale 579

C2lifc~~ia Cov - Rot\sh Creek ~nit #1 1L}8-98-13&oa lC.,E.., 21:72 377

/'. ~ Phillips, Skelly, and Gulf - Hoer,...n C'--J.. 152-102-:1.Jad ICE., 2278 .Pierre Shale 292

920 .. Petroleu.m Corp .. - Halvor B.olf'rud Tract 1 ;¥1 151-97-11da K.. B .. 2370 Pierre S.b..ale 757 956~ Gulf Oil Cc:r·p .. - Bennie-Pie:r::::-e Federal i/1 1L1,8-1 c4-281x~ K.. B. 2339 Pierre :066 .. ..;·:..rn.2:_-,_;~~LL::~. ' ~:;.; ·~:·o_.,:, ~01.: 152-9

I~. J3 V

393

151-1 OJ-8cci ICB.. 2200

1+10

1798 .. :... ..:ole"'..:J. Corp. - 1 AQ ,, • s .. Eelquis'c 150-9 5w•2d.c IC,,B.. 22.'?J

1:, :c:ce S.h.ale 711 1995. S)::allJ:r () Col) - Otto Tanlr 1fl 152-96-JL:,2:o l~" El) 2J28

88.3

Shell. c.1-.;.d i'J1j Pac ic ii~ - N~ f\, 32-15 :i. .Lr 5-101-15ca K~3., 229L~

2667.. o Inc" Gov-t., -I01ary Pace 1,1:1 i46-1. 0:-<1.L:#c b K,.B., 2.JS2

'\Y sr~ell rt.:. Pacific Ra; ... i'J@ P., /IJ2X-2J-1 1.Li.,5-10:;_-23ca

I·C., B g 2L~01 ?ie:rre Sh.ale 650 2?07., St-3ll N,.. Pacific R .. - N;, P,. 14-35-1 J.LY5-101-3500 K .. BQ 2218

68L~ 23~ t Oil - 1 Uo S~ Au-A-:-10 1L1-,5-1. 01-: Oac E.. 2320

612 16?

...·t>-r __ ~oJ ,-;Jl 2786~ ;i.L ., J, ,--, ; ..L.:...:,,o-..:..

2821 w .~ ·J ~:~ . 1;.:."'~-t, - E~.:r:;,~ GlO"'l2.. 1L.~5-99- l(.5~ 2L?7 / 47 0

28L!.,9o L:rd.a IIo ·-I-i., Eu:trt; T1~-u.s~t Estate - r:enry C., }:ystad 152-99-3:lac K .. :3.. 2 6

Pierre Shale 4

2906.. 'l'e~aco Inc~ - Govt;. Doroush 1:E11 (H.C.?.-2) /f-8 151-95-21 ba. J.i..'{ • .:::,"-~ 2 ...;.:.71 ...., 754

3020 .. Si:1.clai:c Oil Gas • -7009-!~cf{o 111 ii.:-6-1 Ob1-J b KQB.. 2501

Pie:::·ra Shale 718

J084 .. Sine Oil and Gas Fed.-7020-McK~ Unit #1 :;.47-10J-11cd ICE.. 2330 628

C.s.:r·oline Hunt Trust Estate - I•'.I.S".r-cin Nalson ;fl-A 149-98-llbd B., 22J2 Pierre Sha.le 226

J61L:-o Calvert D:rillir..g and ?reducing Co., - ..t,.. lfred Brown /)1 ~ .-..~ ....., / r"'j 1, l. ).:.. -70"""' .)~'2..2.. B,. 2415 Pierre Shale 801

0 ::;:::i:1.ta~"lz:.. ?e ..Crol·eu::1 Cor;,o u" s. : 4 5-1 O.5-21.~dd 3,. 2379 774 1.68

tio11al inery Assoc. - ~.P.B.Ro 1Lt5-l 7','" ·;::i .i~ ... .i..,ltl 686

424-0. .. - 11.l':telope-Devonian Unit //4 152-9Li:- IC@B. 2200

~J85u Shell Oil Co. 1.L~8-10:l~15bc K,.B., 2246

J.!1:i..6

r~<"'i Y\::: sources - Anton Zurn Estate 1L}_5-99-1 IC..,3., 2652 Pierre Shale 432 4728. Target l Co. - N. P.R., Rw #1 145-103-9cc K~B., 2630 Pie:c:r·e 81:.ele 68J

4734. Target Oil Co. - N~ ?. R~ Ro #7 146-10.3-9ba K,,B .. 2288

Fiar:r-e Shale L:,807 .. Consolidated Oil Gas Incorp. and Miami Oil - Land Bank jf24-1 15:l.-101-2lid.b K .. B.. 2130 ?ierre 3.32 ):·;· ,-.. ,.... , C ~'I,- ., .. i-·.. l'\) f I·· ·r~:.\;. ·1.~- J-·,- I···' Cl Co (), (A \J, N -..J 0 ,...... (,) f·'· 0 0 ~e~ \J\ \..n C r., • • 0 .. <, ,.

;;:: !·' I·· I v~ ._}. ,... -, ~.~ I ·i. f····I .... •. ~Ij ~·~ i··~' t:r:J t;;~ 1-·'- ~~ ~;::; ,. .,.\. CJ ~~~ )~ •. l) ., \...,) . \...,) ::; \..,J t} ~ \...>,) t) ,, Q \ ..,J" • \..,) 0 • \..,) ~,I • \..,.) " tu {::· c: tJj V\ Ci· tJ \...,) cl' t;' c,, t~i (), t1J\.1\ l·J. ti.iu, C(J t ..J \.)\ " t ([• (• t (IJ e I (0 a I . I t-1 • I c·i" ~ I r··' •· I l) f· ··' l··I I·'· ! l I ' I·) I··' ~-' ,. I··' 1-- J '-[) C I() 0 >' I (i :::, I··' l·J 0 ;i ,., ~u CJ r·s c, tcJ 0 •·(} ~"·0 ~d l' 0) ,...,, O'< .... ; I·'' {'1)\J, fi ..... l',J \..)( p I·'' [\.) c, !\1 t'-' t···"' r:1~ I-'' lV 1... \ t::i_; ~ ..:, !,) I···' :,,. ,.. r,, o ,.. ,, t"...) ~ ·:_, (j) ,o t ti (l) O, ! ,l· (1) '-0 I <:-f·· 0 -..J ~ (i) -..J I r·: 0 ·,) i !.:!,. (i) co ! 0 {[; V.) t~:.i (:·, 1--' f·-·· (!, 1'0 , .... \..,) , ..., 1--'' I·) ,...... >) ,.._; •: r·,, IJ l·t f··''' f-J ,u ;;; 1·J '-0\.D C• 01-·'I··'· ii C> Ii \..,JO (1 !·$ 0,1···' 0 'i I-'· \.0 0 I··' 6 c.:t· f ·J •.,..J f."t ,1· l~) \..n p, ,-; ,.,,, -..J 0\ I·, 1---: () (i} fl') :;; ([) o rs (l) n, r;; (!)' ti\ (J (D p., I··'' cv 0 fl) p p;, p) () p) N fl) I I 0 () 0 (f) I-' (fj 1-J (/.) I···' ,._,_(I) (fl ...,, en l'' ,.,tr.:.... 0 U, ~s ::~t !~.. ,_, t-'j ri ... "'··I tr !:J ,., e ::r t~:J t-:,;:J c; ~) .,._, p <(~"{ f,) 2! fl.} ([l f· J hi 1-1 1-J ,...... J-4 e c..:; l;.J (l) (ti (1) fiJ fD I-'· p l') f;) fJ) ~ ~1J i--J (I) '.,. ...l I-~ ~J 1-; p, • C-l' LJ r ), ,,(D I·" 1D ~--' 0 0 0 .. .) tTJ (i• ~~~ () () 0 () (; (/) () Ii 1·-:1 ~ ~>-.: ~~ ['l l·d 'o ..d ...... l I ~ <> ~ ~ t-·'i ,..1., ~t> ,...,, - \\1 _, {'\) ~-"' I-' tn' :::;:,: I-' i·.) 1--"' t-' () t·= (,) l..J b:J (\.) 1-• N i1 1-~ "r,:.:·- 0 .. (':; 0 '°.t:.- 0 co It Vi~-- [\.) v,. i.11 ',.() 1-··' \..!\ N fj Q\ -.:j ft) \J, .. r-:- --..J (\.) 1') Oq C'~ 1::rJ .... "I~ '° f~ (/l .. ,-) I-·' cl ~;:: ~o 1,; e f-& I-' c-1- tv I I (1) 0) {\) !·-' I ..... o, ::.,1;: N I I I-' Q\ [\.) I-' -,J v,. 170

:i.JJ-99-: z.:s.. 2819

I:1te:r21~ tionc.l I{ucleain - Johnson Jl-24-16 1 J6-1 OL;..~·8ccs. E .. B .. 2614 149J 41-J/72f; :n-Ce:r·r.1.atio11.a.l .Nuclec.? Co:-cpt) - R11stc:1. //1-19-13 1J4-98-22da K.. B.. 2761+

Pie::c-re Shale l.!,Li,76~ Inte:rne:tior.!21 Nuclear Corp. - Silbe:r:nagel //1-1?-2.3 13J-1C3-26cb }Cu3. 29L~1

F ierre Shale 1711

Pie:cre Shale 1283 l.1,L~78,. te:rna.tional 1'Juclea:." Corp., - B. Foust //1-2J-29 136-10J-15cc !':~B.. 2708 1418

L:,480. I:11.te:cna:ciona.l Nuclear Co:::cp" - Govt. 1-1.. Wyckoff //1-2 9 .... 21.:~ 135-103-12c.d E., 2650

Pierre Shale

L.,Lr8k.. I:nt.srnational Nuclee..::c· Corp .. - Govt. .. J~ Cole /Jl-:i.8-25 13 3-1 QL~-1 Baa. IC~ B~ J0?4

•.., ..; I"\ r, L-.:..vv

Inte1..._:rle..:ticf::cl Nucle£::..~ Ccr:)(I - Dc;,v.i.2 :.J6-104--26cc. l,~.o.. 2862

Pierre Sr'~le 1512 - f~::,._·-..,, jf:!.-2CJ-1L;, l JL:,-99-220c

!C., 3 0 2 8lrjL!~ 1239

I11·;:;a::·:1~::Ci.01.:.al 1'Juclelt::..... Co:rp~ - Govt., ,/40 lJL~-106-1.;.bb :-: .. 31> 2837 2.327 -tio2-:al l\Juclear Corp_ - Go-r1-C. ?oe ;i1-J7 :;. JL:--1 o 3-JL:-oc K~3.. 29t.,J

L:1::::e:0112,tions.l 2-Tucle&:r Corpe - Gatzke 1/1-36 1J.5-99~?cc ICoB_, 27 56

Pie1"'re Sh8.le

Intei~:r:o:cicnal Nuclear Corp.. - Davis /h-39 1J5-10L~-20cc K.,3., 2857

Pierre Shale 1710

1179

1273 I11.te:c:--.. a ...cio~1.al N" ..Qclear Cor~i). - I:Iee.gers ,¥1-43 13L}-1 oL:~-36-ba K.,B.. J068

Pierre Sl:-.19.le 1744

Corp;;

1238 - - 172

L~·,,528. I:;:;.~ce:.~r:..t.:.-c Nuclear Corp. - JolfGram #1-33 1J6-103-3Jbc K.B. 2898

4530.. Intern.::,t:cori.al l'Juclea:c Corp .. - Roen §1-13-12 131+-1Ol-35dd K.B. 3051 Pie:,:,re Shale 1349 4531. Inter:::1atio:'la.l Nuclear Corp.. - Dilse #1-45C 133-99-19d.d IC.B.. 2842 Pierre Shale 1392

1.;.532 0 Inter;.1.0.tional Nuclear Corp. - BeTquist //1-38 135-103-266.d Ko3.. 2775 Pier:-.ce Shale 1562

Li,541.. International Nuclear Corp .. - Wellstandt //1-52 1Jlr·-98-J1a.c K.B.. 2796 Pierre Shale 1238 4543.. L'lte:.."'ns.t;ional Nuclea:c Corp., - Flor #1-56 1JJ-106-29dcl K.. B .. 2850 Pie:r:re Shs:.le 2428 I11.·te~r.ta tiona.1 Nuclear Corp. - Swanson //1-54 1J3-99-6cc l{.,Bo 2882 Pierre Shale 134? 4565 .. In~ernatior.:.al Nuclear Corp. - Overbo #1-51 134-98-Jlz.cl K.B.. 2799 1261.J,..

Inte1~:1~tio11al r~·l.1clea.:: Co~~p. - P.rncso::-~ 13.3-98-5db K .. B,, 2785

?ier:-ce S:'1:~.. le 173

le 1271

J44,. Plyrcou~c}1 Oil Co. - Frank ...r:... Fischer //1 13)7-98-llca K.B.. 279?

Pierre Shs.le 7JJ 5.39.. W. H. Hu.::t - Victor H. Kud.rr~ }1 139-97-20cb K,.D. 2.590 Pierre Shale 672 613,, Amerada Pet;roleum Corp. - R. E., Newton /)1 :i. 40-99·· 31 be K.. B., 2697 Pierre Shale 68.5 6.57. Su:~ Oil Co. - w. Beaudoin #1 1.38-99-9cb K.B .. 2640

Pie.r::ce Shale 720

81 O" So,, P:cod" and ·re:x:ota - F ~ J.. War..r..er //1 137-97·~9bb I{..B. 2690

Pierre Shale

8500 W., H~ Hunt - A., A~ Priv:ratsky i-11 138-98-1.5bb K.B. 26.52

712 Skelly Oil Co. - .li.,, Weigum #1 1.38-99-2.5d.b K .. B. 264l,~ Pierre Sha.le 740 1:37-99<,_ Seo

850

2075~ lly 2 Co. - s. Merrill Jl 140-93-J;;d.b K .. B. 2526

2117 .. Te~neco G~s and Trans~ Co. - Cns~er Steele I)-~~e·cs}<:i ;;/1 139-99-16bb IC~ E., 2 61;.4

Pierre Shale

376?. To::n Jo::•c,l",:'l - :.\f;, P. R. R .. /)1 139-98-Jd.c. K.. B.. 2550 Pie:rre Sh.ale 622

L;,237.. Continental Oil Co.. - Zander 1'...... "lderson ,i/1 140-97-JLJ,o.b K.. B.. 2484 Pierre Shale 577 Da}: o t.s·. : •

', ~=ii::/; .:,_..._ ... ,L;;..;o'

... /"">L""- .. •,) '.; J.. 'jOU :J 1-l:tO.~·oc!':ernice.. l f'&cies of gr·olJ.:-:d.- ?1~oc~ -c.r:e _:i:Cl&r:t~ic Coas Pla.i::.;.;, 22nCL I11t;. .I.. ~ p .. 87-95 ..

196L;.. ~ Fielcl ~1:easu:r·ernen·c of· ~cy a:c.Ld TJ., s~ G0ol .. S~v" '1J.:?i."Ce::C-SUPPlY 1535-fl;

Chern5-c~:.l r-2,2.;·;1-:.cQ.s 2 .. s z.. :r.:. c~1cl Jco h:7d.:'"'o :~;0 : fl:fd:.~()~ ... 3. i\Ja:~l ~ ~ias., CO"i..lilCil P~ ::..81-203~

d ... i,~ 4 e;t:.? J)r-, ~ ....l,... ,,..,_ ~"",·r',,... o1~ t;}1e ... '"" ~ ...... /u--; _c:;.._c.;vv~_J.c; :"lor·e.. Roel-:.~... i•iol.?.21tai:'1s

G~est ?lai~s: U 0 S~ Geol.t ,SurvQ P1"*or~" ?a~Jer J •7 5 ',/ : :L 9 p V

s:;:__,,..1.} C,. G~, 1969, Bedrock geoloG-c ot· i:I 01,..·t;!1 ~·:·o:..~t~J. :)9..}:ot;a. C}eolQ 31l:r~,rey r-,1isc O I·1alJ No,, 10 ..

2.,j' 1968~ & S0:1s •.

-,-,,~ ,.,_ ,,. .... --,"I --- ... ~(""I - .,. V ;;.._,_.,~- ,.) ;.,;_ ':1 ,•'.. . ,;:-; .:.. ...:_, •.J _..:. ~- "'"~ - ,-., .. .., r- 1-.... , ..... ,_ ··v' .....,., "., ..J\.) ..,.;._;.~ .. 39 P . - ~; {"-; . ., ::_' -. ' ·. - ""' .,, -•,I. '._,,, ;. ,.,__ • -.I \.,I ..--. ,,-' .~'

,. ... -- ... ,. /"' y' • . ·--~ .. . J \_,J .... ._:,_•J '.J, ....

- ..... _., ._,,. ..,

r;:..!. ·;~ 2..o::-.i. o.:. ,''1::::"" .-...,v1...,.1.,, ) .

- , , ~·t0po3:.·cs;

-.... . - ..... •.-.r• .::·c ~-- 2.. "'"·.t::?-. _!_ ) C~"--"'·"- ~-~ o:: ..~i'"i .'.JE~:.:.:)t.c-.. : I ~ -. • ' ... ~ ..~· 0~ ·~~1. \ 1.::1.~~"C~o..:..1.snea. -cl:8 .Si-S)

1'96?:) .·~ ~,- ·- '": ...... ~::"1,,i--_..,,-...L.j ..; _...., :.:"'lo1:r .:i ace

1)63, Thaorat:cal :=:.:-:...::1 ~ ·:1 :3..:.. 8 '~~"U.~~1.- ·c ~ -~{:: .. ·ci~ ... 0 ~~-~t;e:c 3.esc1)..:rces _Poc• ...... ,~ w ';/

the l Creek ?or- vh Dakote Geolw Survey

.3col-t Co. ,

ie1"' ~ u ~ ~9:-cess) morpho:ogy o~ the ~i ~c tla ~,.~i.s sou:~1. Da}~c:i-: ~;:... Con:pas s • " '1'7 - ; '

-··,1.:'.'• ~:- ,.. r. -:- ,.. , ~~. '. "'· "'' .. 't ,:;., .• \..) ,I 4,".,,i.,..\.(. ., .,., ' ...... ,.-·. ""'r. ~- ·:·f;:Jc;c.: .... :~(_.,;,.: ~J'

t'(" .-., ,-. , ..:.., c.·.. ·-~ I~£:. : ~·~n.1 "' l:. S S O C • 1567-159L!,.,

t:.i.cl in the

sir~" 2 {J geology:

:c··c') .....:. I-C..-~ i9L!.. O~ The ·c:-.:.eo2.,y groundwa:ter motion: Uy Geol., v. ~.. 8: Pu ?.85-941-;,(,

_,,,, 1963, .,:i :f' ic::G.. mett.rod fer rt.. Ga.st11.~er:.c;:J.t of ~c~a t;io11:: u 4i s., Geol., Sc1Xvey 'lJ'ater-Supply .Paper 27 Po

, 1967 1 Introduction to geochemistry: Boo}: Co:::.p~:ny o 721 p.,

,':'.'1-.""'IQ."'1 p,...,.,..,-i 'n.,.,o J L- ,., 055 • ~ K,. Kohler. Ho A.~ C.:..-.J. ... a.u...... , ~ " ,, " .L / ~ :-::td.rolog;y.. -;.,~oY: ex1gi:1eers: EcGraw-Hill Eool:: Company, J~--Q }Jv

.~ i:r \,,,;.·"" .6,::, , 1968 ~ Eyc.rogeo::!.ogy of dese:ct; basins: Gro-..:!l"ld :~1J3.. ..:;e? ;;- "\! ... 6~ ::_:) 0 10-2.2.,

,:".!,; .. ,...'. ,-7 .-:>""r.> I"' ~;:;, ··"-"-""•'-'-->-.. $ v., -v 1927~ Pla~~s as i~dioators of g:rour1.d:wa ter z .I",: ... t;.·eOJ..w SUX"\T .;iv ·:-rater-Sup;:,ly Pa1Jer 577, 95 P"

~.l.·: C)6":;..,. _.i:; ..:..~Lt..,,c1:).,-., ~ .....;-:,,.._~ ___..r,iy ,_,Co Q_~? ..._...:Z.,--· -_i,,.,,v,..,,"t";'",,...if'1T.,,:rs:::~"":t"::1":..-:i~-- ._...... __ J."lot-.;r in ·;;he profile~ Procu Eydrol~ Sympo No. 3:J Natl .. C (Yo..nc i l CarJ.ada ~ }J ~ 5-3 3 ..

1966.si. ~ C1.t1,..r0r..1.t; ..~:;..'"le:::1d.s i11. t1yd:.~0Geolog~r: Earth .:::..2;~:1Cci l~e-vie,(S, "\J. 2s,, P~ JL~5-J64.,

Geel~ - ·: •. "\ ,• ,·~. -.,...... _ ''~·--

.:. \fS.::1 ;--:. :~ ..._.,., _i.,. 5u:::·v ..

,__ .. - .-~. ,''' ~, ·'.- .·· ~·~ C ::-~~c :~;_ "".,.~,,.,,.:..v v..,..,.. 196l;~,, Da1-cc~ca: Dak.

1953) u. Gsol~ Su.::.·""'Ie y ~..Ja ter-Supply :..:...36, J20 P~

1 (') t:. ·1· .:.. JV• ? Zf.ic:ro- S6d.imer.:.ts:

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192 5, c:1e:.:ic.s~J~ ci:ct:r~ac·te:c oJ." r;::o ...c_:.1d u

~v 31-52.

l'fc~t.::-1 Ds:}~o·c:-.. : Geol. 1-;.5~ 53 ?~

C·-e OlOt:£:l a::-1..:. V;;; ~.;, Geolw

;,.,.;.;, V v:; ...... c::· .. ...,,::·-s...:::: ~.:: __ -.~. ·t, '1 ·e, -i -", -·" =· .i.>._;_' 99 p. ::79

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