Water-Mineral Relations of 

Quaternary Deposits in the 

Lower Platte River Drainage 

Area in Eastern Nebraska

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1859-D
Water-Mineral Relations of 

Quaternary Deposits in the 

Lower Platte River Drainage 

Area in Eastern Nebraska

By IVAN BARNES and RAY BENTALL

CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1859-D

Relation of local environmental 

controls to chemical composition 

and selected properties of shallow 

ground water

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1968
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price 20 cents (paper cover)
CONTENTS

Page

Abstract________________________________________________________ Dl

Introduction. _____________________________________________________ 1

Geographic setting_______________________________________________ 3

Geologic setting.__________________________________________________ 6

Grain size and mineralogic composition of the Quaternary fluvial sediments. _________________________________________________________ 8

Occurrence of ground water._______________________________________ 13

Geochemical methods._____________________________________________ 23

Geochemical interpretations-_______________________________________ 25

Ground water beneath the terrace plain._________________________ 25

Ground water beneath the Platte River flood plain._______________ 27

Summary ______________________________________________________ 35

Logs of test holes_____-______________--_---___-___________________ 36

References_______________________________________________________ 38

ILLUSTKATIONS

Page 

FIGURE 1. Generalized geologic map_______________________________ D2

2. Sketch illustrating system of numbering test holes and wells __ 4

3. Map showing locations of test holes, sampled wells, and river

sampling point-_______________________________________ 9

4-6. Maps of the Lincoln city well field showing distribution of 

4. IAP/Ke*Mto values_______._________________ 31

5. Dissolved oxygen concentrations____________________ 33

6. Dissolved iron concentrations.._____________________ 34

TABLES

Page 

TABLE 1. Mechanical analyses of unconsolidated deposits beneath the

terrace plain__________________________________________ D10

2. Mechanical analyses of unconsolidated deposits beneath the

Platte River flood plain._______________________________ 11

3. Light and heavy minerals in the unconsolidated deposits

beneath the terrace plain.______________________________ 14

4. Light and heavy minerals in the unconsolidated deposits

beneath the Platte River flood plain_____________________ 18

5-7. Selected properties and constituents of 

5. Ground water beneath the terrace plain _____________ 25

6. Ground water beneath the Platte River flood plain._ 28

7. Water in the Platte River near Ashland.___________ 29
CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

WATER-MINERAL RELATIONS OF QUATERNARY

DEPOSITS IN THE LOWER PLATTE RIVER DRAIFAGE

AREA IN EASTERN NEBRASKA

By IVAN BARNES and RAT BENTALL

ABSTRACT

The partial pressure of carbon dioxide (Pco,), the degree of saturat'on with 

respect to calcite (/AP/^o.icite), the pH, and the concentrations of selected constituents in solution were determined for water from 52 wells and th* Platte 

River. Compared to the PCO.J in the atmosphere, the average Pco 2 in the ground 

water was many times greater and that in the river water was about twice as 

great. The high Pco2 in the ground water probably results from the absorption, 

by infiltrating precipitation, of carbon dioxide produced in the soil by respiration 

of plant roots and microorganisms. The values for IAP/Kcnc ite for the ground 

water ranged from 0.141 to 1.29 and for the river water the average was 9.6. 

Water from each of the 10 sampled wells on the terrace plain in southeastern 

Saunders County was unsaturated with respect to ealcite, whereas water from 

seven of the 42 wells on the Platte River flood plain was nearly saturated or supersaturated. Of the seven, two were in the Lincoln city well field where hydrologic 

relations indicate that a large fraction of the water yielded by the wells is induced seepage from the river. That more of the city wells did not yieH supersaturated water is surprising in view of the high /AP/£"c.icite values for the 

river water. Supersaturation of water from five of nine sampled well" downvalley from the well field probably is due to the presence of numerous limestone fragments in the Quaternary deposits in that part of the area. A Iso surprising was the finding that the average pH of the water from the ci^y wells 

was 1 unit lower than that of the river water. The presence of both dissolved 

iron and dissolved oxygen in the water from several of the city wells probably 

reflects derivation of the water from two distinct sources: ground water naturally 

in the aquifer and induced seepage from the river.

INTRODUCTION

The purpose of the study described in this report was to re]ate the 

local environmental controls to the chemical composition and selected 

properties of shallow ground water in the lower Platte River drainage 

basin (fig. 1). Among the controls considered were the partial pressure 

of carbon dioxide (Pco2 ) in the atmosphere, the oxygen and carbon

II
\ . R. 8 E. R. 9 E.

T. 14 N.

T. 13 N

Geology from unpublished 

map by R. R. Burchett, 

Conservation and Survey 

Division, University of 

Nebraska

EXPLANATION

3%?

Sandstone, claystone, and Limestone and shale of the Exposure of consolidated 

shale of the Cretaceous Pennsylvanian System rock 

System 

FIGURE 1. Generalized geologic m
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D3

dioxide content of the water, and the minerals with which trQ. water 

has come into contact. Some tentative conclusions regarding the history 

of the ground water are based on petrographic analyses of the unconsolidated sediments through which the ground water percolates, on 

determinations of the ratio of the ion activity product (IAP] to the 

equilibrium constant for calcite (.ZTcaidte) and on determinations of 

certain properties of the ground water.

The field and laboratory work was done by Edwin C. Schuett, Jr., 

who also prepared a preliminary interpretation of the data as a 

thesis for a Master of Science degree at the University of Nebraska. 

Ivan Barnes, who proposed the investigation, conferred with Schuett 

several times while the study was in progress and made most of the 

geochemical interpretation as it appears in this report. Ray Bentall 

compiled the remainder of the text, drawing on Schuett's thesis and 

on information in the files of the Conservation and Survey Division 

of the University of Nebraska.

Acknowledgment is due E. C. Reed, V. H. Dreeszen, V. L. Souders, 

and F. A. Smith of the Conservation and Survey Division, Uriversity 

of Nebraska, and S. B. Treves of the Department of Geology, University of Nebraska, for information and advice. Suggestions made 

by Mr. Souders were especially valuable and are greatly appreciated. 

The study, including preparation of this report, was under the general direction of D. M. Culbertson of the U.S. Geological Survey.

Each well and test hole referred to in this report has been assigned 

a compound number that indicates its location within the Federal 

survey from the sixth principal meridian and base line. The first 

segment of the number identifies the township north, the second the 

range east, and the third the section and location within the section. 

The lowercased letters indicate, in order, the quarter section, the quarter-quarter section, and the quarter-quarter-quarter section. These 

letters are assigned to the subdivisions of the section in counterclockwise direction, as shown in figure 2. Thus, well 13-9-6dbc is in the 

SW!4NWi4SE% sec. 6, T. 13 N., R. 9 E.

GEOGRAPHIC SETTING

The area described in this report includes small parts of Saunders, 

Sarpy, and Cass Counties, Nebr. (fig. 1). Its general location is northeast of Lincoln and south and southwest of Omaha. Because it is traversed by the lowermost reach of the Platte River, a; major drain in 

Nebraska, and is in large part underlain at shallow depth by saturated 

deposits of sand and gravel that yield water freely to wells, it has developed into an important water-supply area.
D4 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

° j0C *>

0 ^o:

Well 13-9\6dbc'

O >C o >< vs

/*- ^s -z>

FIGURE 2. System of numbering test holes and wells,
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D5

A well field alongside the Platte River near Ashland is the principal 

source of water for the city of Lincoln, which is about 30 mile^1 southwest of Ashland. Another near the Platte River at La Platte supplies 

water to the Allied Chemical Corp. A third well field which wilJ supply 

South Omaha is being developed on an island in the Platte River and 

alongside the north riverbank a short distance west of La Platte. At 

the time of the field work for this study (1963), water supplies for 

about 200,000 people were obtained from wells in this area. When the 

well field for South Omaha is developed, the number of people supplied will increase to about 350,000.

The climate of the report area is typical of the middle part of North 

America. The mean annual temperature is about 52°F. On about 10 

days during the winter the temperature drops to below zero, and on 

several days each summer it climbs to 100°F or a little higher. About 

four-fifths of the mean annual precipitation of about 28 inches falls 

during the period of April through September. Monthly amounts of 

precipitation differ widely because a large part of the summer precipitation is in the form of thunder-showers, which may be numerous and 

well distributed or infrequent and scattered. During field operations 

in June and July 1963, temperatures ranged from 80° to 97°F and 

precipitation was above normal. Fieldwork was interrupted in late 

June because extensive flooding resulted from a rain of 2.47 irches at 

Ashland and 6.81 inches at Lincoln during a single 24-hour period on 

June 24-25.

The principal physiographic features of the area are rolling uplands, 

a broad gently sloping terrace plain, and nearly flat valley lands. 

Moderately steep to steep slopes or bluffs separate these features from 

each other. All the points for which information is presented in this 

report are on either the terrace plain or in the Platte River valley.

The terrace plain is a remnant of a formerly more extensive constructional plain. It is 75 to 100 feet lower than the bordering uplands 

and about 50 feet higher than the flood plain in the Platte River valley. 

Except where it broadens abruptly to the north to form a terrace on 

the west side of the Platte River valley, the terrace plain is a southeast-trending linear feature and resembles an abandoned river valley; 

it is referred to as the Todd Valley in some reports on the geology 

and geography of the area, but this name is not in general use among 

the local residents. The terrace plain is about 5 to 7 miles wide and 

has an average southeastward slope of 6 to 7 feet per mile. There are 

several shallow depressions having no surface outlet. About two-thirds 

of the part of the terrace plain shown in figure 1 is within the area 

drained by Wahoo Creek, and the remainder is within the area drained 

by Clear Creek.

285-010 68 2
D6 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNIT7D STATES

The Platte River valley above Ashland differs considerably from 

the Platte River valley below Ashland. The upper segment is 6 to 8 

miles wide and has an average gradient of about 7 feet per mile, whereas the lower segment is 1 to 2 miles wide and has a slightly steeper 

average gradient. Moreover, no bedrock is exposed along the valley 

sides of the upper segment, whereas bedrock is exposed in many places 

along the valley sides of the lower segment (fig. 1).

The soils on the terrace plain, like those on the uplands, developed 

principally on loess (wind-deposited silty clay), and those in the 

Platte River valley developed on silty or sandy alluvium that in places 

was shifted by the wind before vegetation became established. The 

soils differ in their ability to absorb and hold moisture.

In most places on the terrace plain, the surface layer of soil is a 

very dark silty clay loam that has a granular structure and is 6 to 16 

inches thick. It grades downward to a dark-brown silty clay loam that 

has a blocky structure and is hard when dry and plastic when wet. 

Runoff from these soils is slow to rapid, depending on the degree of 

slope. The infiltration rate ranges from about 0.2 to 0.8 inch per hour, 

and the amount of water that can be stored for extraction by vegetation 

is 0.17 to 0.18 inch per inch of soil.

The soils in the Platte River valley generally are dark gray or dark 

grayish brown. In places the soils are so rich in organic material that 

they are referred to as muck, whereas in other places they are almost 

devoid of organic material. Generally the silty or sandy material extends to a depth of more than 20 inches and the substrat-im is sand 

and gravel. As well-defined surface drains are few, the soils of the flatlying bottomlands are imperfectly drained, whereas the soils on the 

higher hummocks are well drained. Where soils are poorly drained, 

alkali conditions are common. Infiltration rates for the more silty 

soils range from 0.2 to 2.5 inches per hour and for the sandy soils from 

2.5 to more than 10 inches per hour. The capacity for storage of water 

that can be extracted by vegetation is 0.16 to 0.18 inch per inch of silty 

soil and 0.06 to 0.15 inch per inch of sandy soil.

GEOLOGIC SETTING

The uppermost bedrock (consolidated rock) in the area is of either 

Pennsylvanian or Cretaceous age (fig. 1). The Pennsylvmian rocks 

consist of a succession of limestones, shaly limestones, and calcareous 

shales, and the Cretaceous rocks consist of sandstones, sandy shales, 

shales, and claystone. Lacking significant interstitial permeability, the 

Pennsylvanian rocks transmit water only through secondaiy openings 

such as solution channels along fracture planes. On the other hand, 

some of the Cretaceous sandstone layers retain a degree of their origi-
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D7

nal interstitial permeability and can transmit small to moderately large 

quantities of water to wells or natural outlets. Mantled by an almost 

continuous sheet of unconsolidated sediments of Quaternary age, the 

bedrock is exposed only in places along the rather steep sides of the 

Platte River valley south and east of Ashland.

The available evidence, obtained by drilling, indicates that the bedrock surface, like the present-day surface, is characterized by hills and 

valleys and that the irregularities of the two surfaces are not p arallel. 

Consequently, the depth to bedrock differs widely from place to place 

within the area. In general, the depth to the bedrock surface below the 

terrace plain ranges from 50 to 175 feet, and below the Platte River 

flood plain, from 50 to 100 feet. The greatest depths, as much as 250 

feet, are along a buried valley that trends northeastward beneath the 

uplands in northeastern T. 13 N., R. 10 E., and northwestern T. 13 N., 

R. HE.

Because the area is only a short distance east of the western maximum extent of the Nebraskan and Kansan continental ice sheets, it was 

a site for accumulation of both periglacial and glacial deposits during 

both of these glaciations of the Pleistocene Epoch. Some of the deposits 

of the Nebraskan Glaciation were reworked or removed by erosion before and during the earlier part of the Kansan Glaciation; similarly, 

some of the Kansan deposits were reworked or removed during postKansan time. The continental ice sheets of the Illinoian and Wisconsin 

Glaciations did not override this area; instead, post-Kansan time in 

this part of Nebraska was characterized by alternating cycles of erosion 

and deposition. The coarser grained deposits, and possibly some, of the 

finer grained, are of fluvial origin; they were derived partly from 

sediments carried into the area by streams draining the unglaciatecl 

area to the west and partly from rock debris transported into tH area 

by the Nebraskan and Kansan ice sheets expanding from centers of 

accumulation to the northeast. The greater part of the finer grained 

sediments consists of loess. Probably the loess originally was almost 

uniformly calcareous, but infiltrating precipitation has leached most 

of the calcium carbonate from its upper layers.

As pointed out by V. H. Dreeszen of the Conservation and Purvey 

Division of the University of Nebraska (oral commun., 1965), it is 

remarkable that such a large volume of unconsolidated sediments was 

deposited in eastern Nebraska during times when the continent stood 

generally high above sea level and so was especially vulnerable to 

stream erosion. Increases in precipitation, blocking of drainageways 

by glacial ice, and depression of the earth's crust beneath and peripheral to the tremendously thick ice sheets may have been the principal factors that combined to create a local environment favoring thick 

accumulation of sediments.
D8 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

The Quaternary deposits underlying the terrace plain have an 

average thickness of about 100 feet and range in texture from clay to 

coarse sand and gravel. The uppermost deposits consists of loess having an average thickness of about 20 feet; the underlying deposits 

consists of silt, sand, and sandy gravel mostly of fluvial origin.

The nearly flat flood plain of the Platte River is underlain by Quaternary deposits averaging about 60 feet in thickness. Although lenses 

of fine-grained sediment are present in places, these deporits are, for 

the most part, moderately coarse grained. Loess, such as mantles the 

coarse-grained deposits beneath the terrace plain, is not pr?sent in the 

Platte River valley; instead, the surficial deposits in the valley consist of silty sand of alluvial origin. Downstream from Ashland numerous angular to subrounded fragments of limestone derived from the 

valley sides are present in the sand and gravel below a depth of 35 to 

40 feet.

GRAIN SIZE AND MINERALOGIC COMPOSITION OF 

THE QUATERNARY FLUVIAL SEDIMENTS

Samples of the fluvial sediments underling the terrace plain and the 

Platte River flood plain were obtained by rotary drilling eight test 

holes. (See fig. 3 for locations and p. D36 for logs.) All the samples 

were sieved mechanically to determine the percentage of each within 

seven different ranges of particle size. Then the fraction for the size 

range y8 to % 6 millimeter was used for the mineralogic examination. 

Bromoform of specific gravity 2.87 was used to separate tl Q- light and 

heavy minerals, which subsequently were mounted in Carada balsam 

for examination by means of a petrographic microscope equipped with 

a recording micrometer.

The particle-size determinations (tables 1, 2) revealed that the fluvial sediments beneath the terrace plain differ in grain-size distribution from those beneath the Platte River valley. Beneath the terrace 

plain, sand is dominant between the base of the loess and depths of 

85 to 95 feet, and gravel is either dominant or at least common at 

greater depths. Beneath the Platte River valley, however, gravel is 

common at nearly all depths, and the sand tends to be coarser than 

that beneath the terrace plain.

The mineralogical analyses show that light minerals constitute about 

95 percent of the fluvial sediments beneath both the terrace plain and 

the Platte River flood plain. As shown in tables 3 and 4, these light 

minerals are mostly quartz, much of which is characterized by inclusions of liquid or gas, and the remainder consists wholly of feldspar 

or of feldspar and calcite. Both the feldspar and calcite grains are 

mainly cleavage fragments. No calcite was found in any of the samples
\ R. 8 E. R. 9 E.

T. 14 N.-

r. 13 N.

Well

EXPLANATION 

O A 

Test hole River samplin

FIGURE 3. Locations of test holes, sampled wells, an
D10 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

TABLE 1. Mechanical analyses of unconsolidated deposits beneath the terrace plain

Percent of sediment

Depth

(feet) Gravel

(>2mm)

Very

coarse

sand 

(2-1 mm)

Coarse Medium

sand :

i (1~

sand

(ntn)

Fine

sand 04- 

J^mm)

Very

fine

sand (JXSilt(<Memm)

Test hole 14-8-23ccc

8.8-10 

10-15 

15-20 -. .

20-25 -- ..

25-30 .

30-35 . 

35-40 .

40-45 ------

45-51 -. .

51-56 --.. ..

56-60 -

60-65 

65-70 

70-75 

75-80 

80-85 -

85-90 

90-95 --.

95-101 

101-105 

105-108.9 .

1.6

.1

.2

.6

1.0

1.9

1.4

2.4

.7

5.3

1.9

2.9

.3

.2

.0

11.1

29.8

37.3

64.4

58.2

63.3

3.9

1.1

1.7

3.5

6.5

7.9

5.9

7.2

2.4

25.9

7.9

5.3

1.0

.9

1.4

19.4

24.4

29.7

27.6

23.9

25.0

19.0

10.3

13.1

12.6

21.0

13.7

14.6

15.7

7.8

22.4

11.7

15.3

6.1

5.0

12.1

21.5

19.6

20.8

4.9

12.3

7.5

52.0

51.2

47.8

43.6

39.7

52.4

53.9

43.6

31.0

24.9

36.0

34.3

43.6

32.2

48.7

32.5

19.0

10.7

2.4

4.9

2.8

21.0

32.5

33.5

35.8

28.3

22.5

22.1

28.1

48.0

18.9

37.2

35.0

44.1

50.8

33.5

13.6

6.6

1.2

.6

.6

1.1

0.8

2.6

2.6

3.1

3.0

1.2

1.4

2.3

8.2

2.2

4.9

6.2

4.6

9.5

3.4

.8

.4

.1

.1

.1

.1

1.8

2.2

1.2

.9

.7

.5

.8

.8

2.0

.4

.5

1.0

.3

1.6

1.1

1.3

.2

.1

.1

.1

.2

Test hole 14-9-20ddd

16-21 . .

21-26 -------

26-31... ---------

31-36 

36-41 .

41-46 ..... ....

46-51 - -

51-56 ------

56-61 

61-66 

66-71 --------

71-76 --------

76-81 

81-86 . 

86-90 -... .

90-95... ...... .

95-101. 

101-106. --. 

106-110.. 

0.6

.7

.5

.8

.3

2.2

2.4

3.8

5.8

.1

.6

.6

.5

.6

1.3

1.2

37.6

12.3

3.4

0.5

1.4

5.6

12.4

7.8

10.8

11.0

21.3

26.2

2.0

16.5

15.4

15.9

31.7

32.5

17.5

55.3

40.0

27.3

4.8

8.3

14.7

22.6

17.8

32.9

26.1

48.0

42.1

18.5

23.2

13.5

14.8

26.6

23.3

21.0

4.8

25.6

18.8

44.9

47.9

41.8

40.4

45.3

42.1

43.3

22.5

21.6

56.5

42.0

48.6

45.9

29.4

33.2

27.8

.9

14.7

30.5

41.5

34.2

33.7

19.4

24.5

9.9

14.9

2.6

3.4

21.2

15.4

19.8

20.6

10.1

8.4

31.6

.8

5.9

17.8

5.3

3.7

2.7

2.3

2.3

.9

.7

.4

.4

.9

1.0

1.1

1.2

.6

.5

.3

.3

.7

.8

2.7

3.7

.9

2.1

2.0

1.4

1.6

1.4

.6

1.0

1.3

1.1

1.0

1.0

.8

.7

.5

.9

1.5

Test hole 14-9-30ddd

12.5-15 -------

15-20 . 

20-25 

25-30... ..........

30-35 

35-40 

40-45. 

45-50 

50-55 

55-60 

60-65 

65-70 

70-75 .... .

75-80...... .......

80-86 .

86-90... . ..........

90-95 

95-100 ---------

100-105 -------

105-111 -- 

1.3

.0

.6

2.3

.4

.6

1.8

1.0

1.2

9.4

.9

.2

2.2

24.2

48.4

2.2

65.2

56.3

52.1

97.6

1.6

.8

3.1

4.7

2.7

3.1

8.9

4.1

3.0

4.4

2.6

1.1

10.3

26.4

23.5

2.7

16.5

14.0

8.6

2.1

4.0

3.5

4.8

10.8

8.5

11.7

12.0

9.5

10.6

10.4

5.3

6.5

11.1

9.8

7.3

13.2

4.7

6.8

7.3

.0

22.8

22.8

24.5

44.7

33.2

33.3

26.2

37.7

46.2

33.2

22.4

28.8

30.5

17.5

10.3

35.9

7.5

10.8

18.1

.0

58.8

61.7

54.6

32.5

48.2

42.5

45.3

42.7

35.4

37.9

52.6

55.1

39.7

18.6

9.1

38.4

4.9

9.5

12.1

.2

8.0

10.0

10.9

3.7

5.9

8.4

4.9

4.6

3.3

4.4

14.6

7.9

5.3

3.2

1.2

7.2

.8

2.0

1.5

.1

3.5

1.4

1.5

1.4

1.1

.6

.9

.5

.5

.8

1.7

.5

1.1

.3

.4

.6

.5

.6

.3

.1
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA Dll

TABLE 2. Mechanical analyses of unconsolidated deposits beneath the Platte River

flood plain

Percent of sediment

Depth 

(feet)

Very 

Gravel coarse 

(>2 mm) sand 

(2-1 mm) ;

Coarse Medium 

sand sand 

(1- (Yr 

V>t mm) y± mm) ;

Fine Very 

sand fine Silt 

(Ji- sand 04- (<M«mm) 

Y% mm) H« mm)

Test hole 13-9-24ddc

12.4-15 .........

15-20 ..........

20-23.2--.....-.

23.2-23.5... ........

23. 5-25»._ _---.--..

25-30 -------

30-35. ...

35-40 --.. _.

40-45 .........

45-50 ---------

50-55 .... .

55-60 ..........

60-68.5... ........

68.5-70- . 70-75 . .

75-80 .........

80-84.5 .

14.2

7.5

3.1

21.5

19.2

11.5

25.6

12.7

24.6

11.6

20.2

10.5

8.5

18.7

36.5

27.2 

27.1 

14.5

27.9 

17.4 

17.9 

19.2 

48.0

24.0 

11.6 

23.9 

6.9 

20.3

32.8 

35.5

35.3 

39.2 

46.3

27.9 

38.9 

33.6 

31.2 

25.8

25.8 

25.0 

35.1 

26.7 

34.5

31.7 

23.3

16.6 

20.6 

28.6

18.1 

19.0 

31.2 

20.3 

10.9

19.3 

41.0 

13.2 

45.4 

25.4

14.3 

3.4

2.6 

4.0 

5.2

3.0 

4.3 

5.0 

2.8 

2.1

6.0 

10.3 

4.3 

10.0 

9.7

2.3

.5

1.1 

1.1

.8

.6 

.3 

.4 

.1 

.1

.1

.1 

.1 

.4

.7

.2 

.1

3.2 

.6 

1.5 

100.0

1.1 

1.0 

.4

.7 

.4

.3

.5 

.4 

.2 

.9

.1 

.5

Test hole 13-ll-36dad

1. 5-5 .... ......

5-10 ..........

10-15 .. ...... .

15-20... ..........

20-25 .........

25-30... _. -.-.-.. .

30-35 .........

35-40 ---.--.

40-45 --..-.

45-50 ...... ...

50-55 ..--..

55-601 .........

60-65 . 

65-70- 

70-75- - .--.

75-80-----.-..--.

80-85 ---------

85-90 ----------

90-93 --------

93-95 ..........

1.1

.4

5.0

12.3

21.4

34.1

33.5

34.5

46.0

30.6

11.7

30.8

31.7

30.6

27.1

75.5

70.9

49.4

74.2

1.8 

.8 

14.9 

16.1 

24.4

30.9 

27.5 

35.5 

31.7 

23.9

23.9

47.3 

46.9 

37.3

46.7 

19.0 

23.5 

32.4 

23.6

9.5 

4.6 

19.1 

21.3 

22.0

18.7 

18.8 

13.4 

15.0 

24.1

37.4

12.5 

12.9 

12.9

10.7 

3.3 

4.0 

9.6 

1.8

53.4 

28.1 

36.7 

34.0 

23.3

11.5 

12.8 

12.2 

6.0 

14.7

21.7

6.4 

6.6 

10.9

8.3

1.7 

1.0 

6.0

.2

29.4 

57.5 

22.3 

15.3

7.7

4.0 

6.3 

3.7 

.8 

6.0

4.6

2.4 

1.4 

7.3

5.9 

.3 

.4 

2.3 

.2

o. 2 

8.3 

1.7 

.7 

.7

.4 

.6 

.4 

.3 

.6

.4

.3

.4

.8

.8 

.2 

.2 

.2 

.1

1.6 

.4 

.4 

.4 

.4

.4 

.5 

.3 

.3 

.3

.4

.3 

.3 

.3

.5 

.1 

'.2 

.1

Test hole 13-13-24ddd

10-15. 

15-20 ........

20-25 . ........

25-30 ----------

30-35 - ---------

35-40 ..........

40-45 -. ------ .

45-50 -.-.-. ... .

50-58. .

53-60 

Co-70 ..........

70-75 

75-80 --------

80-85 ---------

0.0

.0

.3

.0

23.3

35.4

43.3

36.5

32.1

7 4

11.5

52.8

29.0

35.1

51.1

0.2 

.3 

.9 

.3 

26.1

20.4 

34.6 

24.6 

21.4 

3.5

13.5

20.6 

34.1 

24.9 

32.5

0.4 

.3 

.9 

.3 

19.7

18.0 

15.1 

23.8 

21.3 

10.5

7.9 

9.0 

12.5 

15.0

8.8

1.4 

3.5

10.2 

3.9

7.8

10.8 

4.3 

9.0 

12.9 

16.5

18.4 

6.6 

7.0 

9.4 

2.5

43.0 

66.7 

73.2 

69.4 

16.8

11.4 

2.2 

4.5 

8.1 

47.4

41.2 

7.9 

12.7 

10.9 

2.9

44.7 

25.0 

12.7 

23.5 

4.5

2.5 

.4

.8 

2.5 

12.4

6.1 

2.1 

3.5 

3.3

.8

5.4 

4.2 

1.9 

2.7 

1.9

1.5 

.2 

.8 

1.8 

2.2

1.5 

1.1 

1.2 

1.5 

1.4

No sample.
D12 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

TABLE 2. Mechanical analyses of unconsolidated deposits beneath the Plotte River

flcod plain Continued

Percent of sediment

Depth 

(feet)

Very Coarse Medium 

Gravel coarse sand sand 

(>2 mm) sand (1- (J£- 

(2-1 mm) y-i mm) J^ mm) J.

Fine Very 

sand fine Silt 

(U- sand (H- KMenmi) 

i mm) Yn mm)

Test hole 13-13-24ddd Continued

85-90..............

90-95..............

100-105 .-..-....

110-114.2... .......

46.6

28.3

38.7

63.6

62.6

18.4

21.8 

34.3 

37.0 

16.8 

13.2 

17.2

20.3 

26.9 

15.7 

7.3 

7.8 

33.0

4.6 

7.2 

3.4 

7.0 

7.9 

24.8

3.9 

2.2 

3.3 

4.6 

7.5 

6.1

1.4 

.7 

1.0 

.4 

.8 

.3

1.3 

.4 

1.0 

.3 

.1 

.3

Test hole 13-13-29db

2.6-7. ...........

7-11 ...........

15-19. ..........

19-23.... ..........

23-27- ...... ...

27-31..... .........

31-35 - ..........

39-42 .

42-46............

46-50 

50-51.5- .

52.5-54.. _ ...

54-54.5 ------

7.5

9.8

15.0

22.2

25.1

11.6

10.5

27.8

31.1

20.8

37.5

49.1

20.2

9.6

7.9 

13.2 

18.1 

16.6 

15.1

14.1 

19.6 

13.4

21.8 

25.8

38.0 

27.3 

25.5

27.6 

26.7

14.2 

21.8 

31.3 

31.5 

21.9

24.3 

31.2 

25.7 

20.5 

20.9

26.4 

23.1 

15.4

25.5 

28.9

32.8 

37.6 

32.5 

23.6 

23.9

17.9 

27.4 

36.0 

20.0 

14.6

8.7 

S.7 

8.4

17.8 

18.9

32.8 

16.1 

7.4 

12.6 

15.4

14.7 

8.5 

13.2 

8.9 

6.6

5.3 

2.0 

1.4

6.6 

9.9

3.5 

1.2 

.8 

.5 

1.2

3.5

1.5 

1.1

.7 

.7

.6 

.1 

.1

1.4 

3.5

1.4 

.3 

.1 

.3 

.4

.5 

.2 

.1 

.3

.4

.1 

.3

.1

.9

2.5

Test hole 13-13-32ad

18-22 -

22-26... -----...-.

26-30 ----------

30-34... ..

34-38 

38-42 

42-46 

46-60.. ........

50-54. 

54-58 

58-62 . ------

62-66 

66-70 . 

70-721-.. 

72-76 ......

76-80 .

80-84. .

84-88 ...... ...

88-92 .......

92-94 ......

2.8

11.2

21.2

21.4

18.9

33.7

3.8

11.6

16.0

15.2

14. 5

49.8

41.3

34.3

33.9

30.7

36.7

40.3

41.1

4.3 

14.4

17.7 

22.9 

17.6

20.2 

7.6 

18.0 

18.4 

17.9

14.4 

18.3 

21.9

25.4

29.9 

24.3 

34.0 

32.2 

24.0

19.2 

22.4 

23.4 

29.9 

28.5

22.1 

16.2 

23.7 

28.7 

22.4

16.5 

12.3 

21.6

20.3

20.9 

21.9 

19.8 

15.7 

13.8

41.0 

28.0 

22.0 

19.1 

26.0

16.5 

33.3

26.4 

24.8 

26.5

31.5 

11.8 

12.2

15.9

11.9

18.6 

7.7 

8.2 

11.3

25.4 

19.9 

13.1 

5.2 

7.8

5.9 

34.5 

17.1 

11.0 

15.4

20.5 

6.7 

2.5

3.6

3.0 

3.8 

1.6 

2.8 

8.5

5.3 

2.8 

1.7 

.9 

.7

1.0 

3.8 

2.4 

.9 

2.1

2.0 

.8 

.3

.5

.3 

.4 

.1 

.3 

.9

2.0 

1.2 

.9 

.5 

.6

.5 

.8 

.8 

.3

.5

.7 

.4 

.1

.1

.2 

.2 

.1 

.5 

.3

i No sample.
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D13

from the fluvial deposits beneath the terrace plain. However, as V. L. 

Souders (oral commun., 1965) identified crystalline calcite in samples 

from a hole drilled on the terrace plain a short distance north of the report area, it is likely that calcite is present in at least a few places 

beneath the part of the terrace plain within the report area. Samples 

from test hole 13-9-24ddc (about 2 miles north of Ashland and a very 

short distance downstream from the contact between Cretaceous and 

Pennsylvania!! rocks) contained a few traces of calcite, but samples 

from the other test holes (all downstream from test hole 13-9~24ddc) 

contained considerably more. Calcite constituted more than 50 percent 

of the light minerals in samples from the base of the sand and gravel 

penetrated by test hole 13-13-29db. It is assumed the calcite grains 

were derived from limestone fragments that were crushed by the 

rotary action of the bit when the holes were being drilled. Calcite was 

the only carbonate mineral identified in any of the samples.

Although constituting a minor percentage of the sediment, the 

heavy-mineral fraction is more varied in composition. In sample from 

both the terrace plain and the Platte River valley, the chief heavy 

minerals were magnetite-ilmenite, zircon, garnet, and hornblende. 

Other amphiboles, pyroxenes, epidote, tourmaline, sphene, leucoxene, 

and hematite complete the suite of heavy minerals common to the sand 

and gravel in both parts of the area. Hematite is less abundant in 

samples from test holes drilled 011 the terrace plain than in samples 

from test holes drilled in the Platte River valley. Moreover, pyrite and 

limonitic pseudomorphs after pyrite were noted in the Platte Kiver 

valley samples but were not seen in any of the terrace-plain samples.

OCCURRENCE OF GROUND WATER

The unconsolidated deposits underlying the terrace plain and the 

Platte River valley are water saturated below a level that ranges in 

depth from as little as a fraction of a foot to as much as 60 feet below 

the land surface. The average depth to the water table, or top of the 

zone of saturation, is considerably greater beneath the terrace plain 

than beneath the Platte River valley. All the ground water is regarded 

as under water-table, or nonartesian, conditions even though locally 

it may be confined under very slight artesian pressure.

As the soils in the area are highly permeable for the most part, they 

readily absorb rain and meltwater from snow. However, soil permeability is only one of the factors that determines the amount of rain 

or meltwater that infiltrates to the zone of saturation. The amount of 

water and the length of time it is available for absorption, the temperature and relative humidity of the air just above the land surface, the 

moisture content of the soil, and vegetal activity all may be factors

285-010 68 3
D14 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

TABLE 3. Light and heavy minerals in the

[Tr.,

Depth

(feet)

Heavy minerals (percent)

Opaques

SS

O a be w

03 :S

§

Leucoxe

0

Hemati

3'o

Nonopaques

Zircon

CO

Colorles

Yellow

1 

M

g o

| 

p.

CQ

Tourmaline

C5 

3

«

1

a

2

O

A

i

PC

>.

B

 o

o

Hornblc

s>

Actinoli

Test hole

8.8-10..........

10-15..........

20-25..........

25-30-.....-.-.

30-35..........

35-40..........

40-45..........

45-51..........

51-56..........

56-60..........

60-65..........

65-70-----...-

75-80.. ....... .

85-90-------.-

90-95-.. _______

101-105. ...... 

105-108.91......

41

34

27

42

31

56

38

27

31

39

21

34

35

38

35

34

38

54

26

o

9

1

1

Tr.

1

Tr.

Tr.

Tr.

Tr.

1

Tr.

1

2

1

2

3

1

1

1

1

1

4

1

1

1

1

Tr.

2

Tr.

Tr.

45

35

34

31

44

3?,

57

39

98

36

40

9?,

35

36

39

38

34

39

54

?,7

19

94

?,3

?,0

13

18

11

14

?,0

15

?1

9!3

1fi

16

18

16

13

16

15

13

8

10

13

1?

9

11

9

11

16

19

15

11

18

I9

11

9

9

10

3

17

2

2

1

1

Tr.

Tr.

1

Tr.

9

4

5

6

6

6

11

1

Tr.

Tr.

Tr.

9»

37

37

33

?3

9»?o

915

36

97

36

34

43

3?

34

3?,

?8

3?

94

41

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

1

1

3

2

1

Tr.

1

1

Tr.

1

1

2

3

4

9

9

2

3

4

1

1

1

o

1

2

<>

4

Tr.

3

1

1

1

1

3

1

1

1

Tr.

1

2

3

1

1

6

11

14

T>

fi

14

4

16

16

18

1490

8

g

9

8

g

6

Test hole

16-21. ...... ..

21-26... __ ..

2fr-31. ........

31-36.... _ ..

36-41. ........

41-46.........

46-51.. _ ....

51-56.........

56-61.. ..... _.

66-71.........

71-76.. .......

76-81.........

81-86.........

86-90.........

90-95.........

95-101.. ......

106-110........

45 

41

30 

48 

32

46 

38 

30 

42

43

54 

52

52 

41

58

38 

50 

42

34

Tr. 

1

1 

1 

2

3 

3 

1

1 

2

2 

1 

1

3

Tr.

4

1 

1 

Tr. 

3

2

4 

3 

3 

4 

3

4 

4 

2 

2 

1

3

2 

2 

2

46 

43 

31 

52 

36

53 

44 

34

46 

47

60 

56 

56 

44 

60

44

52 

44 

40

17 

21 

22 

13 

19

17 

15 

24 

13 

18

10 

15 

13 

18 

9

24 

16 

12 

19

10 

10 

10

7 

8

7 

9 

3 

6 

6

8 

5 

7 

5 

C

2 

6 

6 

5

3 

1 

3

3

Tr. 

2 

1

5

6 

3 

4 

4 

4

6 

7 

7 

3

Tr. 

1

"Tr'." 

Tr.

Tr.

Tr.

30 

33 

35 

20 

30

24 

26 

28 

24 

31

24 

23 

24 

27 

19

32 

29 

?5

27

Tr. 

Tr. 

1 

Tr. 

Tr.

Tr. 

-_.---

Tr. 

Tr.

Tr. 

Tr. 

Tr. 

1

Tr.

Tr.

Tr.

1 

2 

2 

1 

Tr.

1 

1 

1 

1 

1

Tr. 

2 

1 

1 

1

1

Tr.

5 

6 

6 

2 

5

2 

3 

3

5 

5

3 

4 

4

7 

3

4 

3 

4 

3

1

Tr~o 

Tr. 

1 

Tr. 

1 

1

Tr. 

Tr. 

Tr.

Tr.

3

2

6 

fi

9

6

8

3

7 

8 

5 

5

3

4

10 

4

7 

3

7 

8

Tr.

"Tr"." 

Tr. 

Tr.

------

------

» Heavy-mineral sample lost during analysis.
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D15

unconsolidated deposits beneath the terrace plain 

trace]

Heavy minerals (percent) Continued

Nonopaques Continued

o

£

H

-2 "So

<1

o>

G.

0

Q

"S

T3

w

Rutile

a £

,Qi

«

rown

£ _o"3

^

Garnet

^ 3

O

-M

PH

"3

H

C

o

B

0

3

83

CO

83 

Q.

^

Light minerals (percent)

Quartz

 aa

PH

Jt "3

1 1

"3 

"S

H

"C

03

erentia

£50,^3 

2§

f^

o

03

O

i

^

o

1

<s

14-8-23ccc

Tr.

1

1

Tr.

Tr.

1

1

3

Tr.

Tr.

1

1

Tr.

3

1

1

Tr.

1

Tr.

4

3

4

4

3

3

3

?

3

1

4

8

fi

3

3

3

3

9

3

3

5

4

3

3

5

7

3

4

3

2

1

1

2

Tr.

9

8

9

11

10

8

5

9

8

9

6

f,

7

6

11

10

13

10

9

14

3

1

1

1

1

1

9

1

Tr.

3

3

9

9

10

14

10

9

11

9

10

7

6

8

T>

10

Ifi

13

9

14

1

9

Tr.

Tr.

Tr.

Tr.

i

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

1

Tr.

1

--

Tr.

Tr.

Tr.

Tr.

as

63

6?,

67

fifi

as

64fi?

6?

67

64

6fi « >

68

as

64

64

64

64

64

 >. >

??

?7

?,3

?,0

9,3

9,1

?9

19

19

?fi

93

99

94

9?

93

90

93

90

88

85

89

90

86

86

91

87

86

83

88

88

87

90

87

86

8fi

87

84

15

10

10

11

13

9

13

12

14

12

11

13

9

12

12

12

13

12

14

1

9

1

Tr.

1

1

1

9

1

Tr.

Tr.

Tr.

1

1

1

Tr

Tr

1

Tr

Tr

1

1

Tr

Tr

14-9-20ddd

1

1

Tr.

Tr.

Tr.

Tr.

1

1

1

1

i

Tr.

1

Tr.

1

1

1

1

1

1

1

Tr.

1

1

1

Tr.

Tr.

Tr.

9

9

3

9

3

9

9

9

4

1

1

9

?

4

3

3

3

2

3

1

Tr.

2

9

9

2

2

9

9

Tr.

1

1

1

3

Tr.

Tr.

6

7

9

10

8

11

8

8

7

7

6

3

7

4

7

P

1

1

9

3

2

2

c,

2

2

9

3

9

1

2

8

11

13

10

9

9

9

S

8

3

10

S

11

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

1

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

79

6,S

as

69

71

73

P.3

7?

77

14

9.S

an

97

99

19

on

97

93

?0

95

19

19

88

S5

94

93

95

91

93fin

91

90

96

90

89

9?

95

%

9

5

4

6

4

9

6

9

9

9

6

10

9

8

5

4

4

2

1

1

3

4

Tr.

1

2

-Tr"

Tr

Tr

Tr

Tr

1
D16 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

TABLE 3. Light and heavy minerals in the unwnsolidated

ITr.,

Depth

(feet)

Heavy minerals (percent)

Opaques

j2 4^ Magneti ilmeni

s>

a

Leucoxe

a

Hematit

3"S

EH

Nonopaques

Zircon

Colorles

1

Brown a

5

3"o 

EH

1

 a

02

Tourmaline

3

c

?

Green-b

o

ft

p

is

c

Hornble Actinoli

Test hole

12.6-15.........

15-20.........

20-25.........

25-30.........

30-35.. ..... ..

35-40.........

40-45.........

45-50.........

50-55.........

55-60.. ....

60-65.........

65-70.........

70-75.........

75-80.........

80-86.. ...... .

86-90... ......

90-95.........

95-100........

100-105........

105-111--------

32

25

26

51

34

33

29

34

48

36

19

31

30

24

26

29

33

35

29

48

Tr.

2

1

1

Tr.

3

1

Tr.

Tr.

1

3

3

3

2

1

2

1

9

3

1

2

1

2

3

2

2

2

3

2

3

2

1

1

3

3

Tr.

33

?9

30

S3

36

34

34

38

50

3S

35

35

30

31

3?

34

39

34

48

18

34

?3

16

19

?3

1?

16

18

?3

13

?4

15

?8

15

18

19

13

15

9

7

8

1?,

14

9

7

5

7

13

10

8

7

7

8

8

7

11

7

2

1

1

1

3

1

9

4

6

5

12

10

8

11

10

13

9

8

9

6

1

35

44

31

?5

34

38

30

?7

?9

35

50

33

40

33

45

36

35

34

31

?6

1

Tr.

1

Tr.

Tr.

1

Tr.

Tr.

Tr.

1

1

Tr.

3

1

1

Tr.

1

3

1

2

2

1

1

1

2

Tr.

1

1

5

4

2

5

3

8

5

5

5

4

5

7

6

9

4

6

6

5

1

T~.

Tr.

Tr.

Tr.

T-.

Tr.

1

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

1

Tr.

2

Tr.

2

9

6

8

5

6

7

8

8

4

5

6

8

4

11

5

6

6

4

4

5

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D17

deposits beneath the terrace plain Continued 

trace

Heavy minerals (percent) Continued

Nonopaques Continued

Tremolite

S

<D

2

i

Q

£

o

a

Rutile

g 

2 

.a

T3

a

.a 

«S

1

Garnet

_«

"o 

0

1

"a 

o

<D

ta

<o

1 

1GO

0 

03

a

Light minerals (percent)

Quartz

1

£

§ 

 i 

|

M

3'o

<D 

.03

S3

g 0>

 3^ 

Pn

 3 

o

£

1

1 _«

14-9-30ddd

Tr. 

Tr.

Tr. 

Tr.

Tr. 

Tr.

Tr.

1

Tr.

1

1 

1 

1

1

1

Tr. 

Tr.

Tr.

1

1 

1

Tr.

1

1 

2

1

2

Tr.

Tr.

7 

4 

6 

3 

3

3 

5 

4 

3 

3

4 

3

a

4

2

3 

4 

3 

4 

4

2 

1 

3 

1

2

2 

2 

2 

2 

2

2 

2

9

1 

1

4

3 

1 

2

---- -

" Tr "

8

g

13

7 

7

8 

10

g

6

fl 

10 

8 

17

7

8 

7 

6 

10 

9

1 

3 

1 

2 

3

2 

1 

1 

Tr. 

3

2 

1

1 

Tr. 

2

2 

2 

1 

2 

1

fl 

12 

14 

fl 

10

14

g 11 fl fl

11 11 

g

17

g

10 

9

7

10

Tr.

Tr.

......

Tr.

Tr.

Tr.

Tr.

Tr.

Tr. 

Tr.

Tr.

1 

Tr.

Tr. 

Tr. 

Tr.

Tr.

Tr.

Tr. 

1 

Tr.

Tr. 

Tr. 

Tr. 

1

66 

63 

62 

66 

62

67 

68 

59 

69 

59

62 

58 

68 

69 

66

63 

64 

56 

61 

65

19 

24 

25 

22 

26

20 

21 

26 

18 

25

23 

26 

19 

17 

19

22 

20 

28 

23 

22

85 

87 

87 

88 

88

87 

89 

84 

87 

84

85 

84 

87 

86 

85

84 

84 

84 

84 

87

14 

13 

10 

11 

11

11 

11 

14 

12 

14

13 

16 

11 

13 

13

13 

14 

14

IS 

12

1

1 

2 

1

1 

1 

1 

1 

1

Tr. 

1 

1 

1 

1

1

2 

1 

2 

1

....

"Tr'

1 

Tr.

Tr. 

Tr.

Tr.

Tr. 

1

....
D18 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

TABLE 4. Light and heavy minerals in the unconsolidated

[Tr.,

Depth (feet)

Heavy minerals (percent)

Opaques

o

a

fi

2

1

I

£

I

B

T:

P.

CD

d 

1

3

Nonopaques

Zircon

9!

"3

a

"3 Brown

P.

o

EH ! 

CQ

TourmaUne

i

3

d

1

S3

O

o

a 

£

1

-S 

§

1

Test hole

12.4-15... ......

15-20.. .......

20-23.2. ......

23.2-25 '---_- _

25-30.... .....

30-35... ___ ...

35-40... ___._.

60-68.5. _.....

68.5-70 ......

70-75 -.....

75-80 ......

14

36

31

24

?5

43

30

38

51

41

35

?5

24

19

Tr

Tr

1

Tr

Tr

1

3

3

14

?,

8

5

4

4

5

Tr

3

1

3

5

fi

7

3

8

10

8

3

9

9

1

9

Tr

1

?,

?,

1

9

4

Tr

1

Tr

36

41

49

41

38

53

40

39

56

44

41

31

31

97

1?

15

17

19

15

10

16

10

14

14

11

14

6

6

5

3

7

5

1

7

8

3

7

6

3

4

4

3

6

3

3

6

9

4

3

4

4

4

5

Tr.

Tr.

Tr.

26

?,1

?,1

30

?7

19

96

?0

9?,

SO

25

?,1

91

1

1

1

2

1

2

2

1

1

1

1

2

Tr.

Tr.

Tr.

Tr.

1

Tr.

2

1

3

4

3

1

1

3

3

5

2

1

Tr.

1

Tr.

Tr.

Tr.

Tr.

1

3

Tr.

16

13

14

1?

10

10

11

18

7

?1

15

?,4

?,6

33

Test hole

1.5-5... .._.___

5-10-.....-.

10-15... ______

20-25 _____

25-30... _____

35-40.. .____. _

40-45,.. ______

45-50... ..____

50-55 --.

55-60 ...... . .

60-65... _.-._.

65-70... ______

70-75 .....

75-80....--...

80-8.r> ......

85-90... ... ...

90-93... ......

93-95... .._._.

00

21

3ii '3

3(3

10

?7

25

40

35

33

19

39

33

5

1

3

1

1

1

3

1

Tr

1

1

9

1

3

1

4

4

3

5

6

4

3

3

1

5

4

6

9

7

1

Tr

Tr

1

1

Tr

Tr

Tr

98

33

41

99

31

41

1fi

9Q

41

38

98

38

97

43

37

14

15

10

19

16

17

IS

IS

99

99

21

90

19

18

10

g 9

11

g

8

8

4

8

4

6

4

8

4

4

4

4

3

3

1

3

3

4

3

1

4

1

5

5

1

1

1

1

Tr.

Tr.

1

Tr.

Tr.

1

33

18

90

?fi

33

97

?,9

34

30

30

3?

17

99

90

99

14

1

Tr.

Tr.

Tr.

Tr.

Tr.

1

1

1

Tr.

Tr.

Tr.

3

4

3

5

3

5

6

2

4

3

2

3

6

4

3

4

Tr

1

1

9

Tr.

Tr.

1

1

1

1

1

1

2

1

1

3

99,

30

16

16

13

18

13

3?

71

13

9

10

13

93

?.

14

35

Teat hole

10-15.. ------

15-20----- -

20-25__-_..-.

25-30. _. ......

30-35-_. ......

35-40.... .....

40-45.........

45-50.........

50-58.. ._.....

58-60.........

14 

12

11

12

?3

37

26

OQ

239?,

1

Tr.

Tr. 

1 

1

9

8

10

12 

4

2 

10 

3 

6 

9

Tr. 

Tr.

Tr. 

Tr. 

1 

Tr. 

Tr

4 

4 

5

""3"

"Tr"

29

24 

25 

29

27

39 

39 

32 

30 

33

13 

14

7 

5

7

6

8 

8 

4

5

7 

Tr. 

4 

2 

1

1

1

9 

9 

1

4 

3 

4 

4 

3

1

3 

1

1

Tr.

Tr.

24 

17 

15

11

10

13

1 

1 

Tr.

Tr.

Tr. 

Tr.

Tr.

1

2

9

T". 

T\

2 

1 

T\

2 

2

2 

3 

1 

3

2

2 

1 

1 

4 

5

9 

18 

17 

14 

13

8 

8 

6 

8 

10

1 No sample.
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D19

deposits beneath the Platte River flood plain 

tracel

Heavy minerals (percent) Continued

Nonopaques Continued

CD

Actinoli

ID

Tremoli CO 'So

'O a 

§ 

3

o

'ft g

^

o

"3

Garnet

co

8 "o 

O S

"3 

'o

Biotite

ID

Stauroli ID

"3 

P.

Light minerals (percent)

Quartz

e '3

s

§

Inclusio

3"o

-3

_c| "S

 3

e

s

3 

p,

 § 3

CD

g

 3 

"So

03

s

2

Microcli Calcite

13-9-24ddc

1

1

Tr.

Tr.

Tr

Tr

Tr.

1

Tr

Tr,

Tr.

Tr.

1

Tr,

Tr

2

Tr

Tr

Tr

1

2

Tr.

4

4

5

3

3

1

?,

?:

5

3

4

5

4

Tr

3

?:

?,

1

1

1

1

1

Tr

1

fi

5

5

12

12

4

R

8

fi

7

f,

1

1

1

9

9

1

?(

10

R

5

13

8

13

g

10

1?

fi

8

9

8

8

Tr.

Tr.

Tr.

Tr.

Tr.

2

1

1

1

Tr.

Tr.

1

1

1

Tr.

Tr.

Tr.

1

Tr.

Tr.

Tr.

1

ec

57

52

CA

46

48

45

AQ

AQ

49

47

CA

34

Qi

«M

37

40

39

38

OQ

40

41

40

41

38

4?

40

90

92

Q1

93

92

BQ

SQ

85

OQ

86

CO

CO

87

QQ

90

g

7

8

7

10

10

13

10

12

10

Tr

Tr.

Tr

Tr

Tr

Tr,

Tr,

1

13-ll-36dad

Tr

.-_-.-

--.._-

......

.....

Tr

Tr.

....-

1

Tr,

2

3

1

2

1

1

2

3

Tr

4

5

5

9

2

2

9

fi

3

1

1

3

3

£

1

S

2

3

1

9

1

2

1

?,

2

4

1

1

2

4

2

7

7

13

Ifi

n

7

5

5

8

9

IT

3

8

10

7

3

3

3

3

3

4

9

1

1

?

3

5

o

2

10

19

8

15

11

7

5

8

6

10

V>

17

1?

7

Tr.

Tr.

Tr.

Tr.

 <

i

Tr.

Tr.

Tr.

1

Tr.

Tr.

Tr.

\

j

Tr.

Tr.

Tr.

j

Tr.

Tr.

Tr.

1

1

44

Cfi

55

49

48

48

AQ

58

,58

,58

60

56

61

,58

56

45

36

40

3fi

40

40

41

36

30

30

3?

OQ

29

30

°9

89

86

89

91

89

88

88

89

86

88

89

00

85

8H

QC

10

14

11

10

12

12

9

10

11

11

11

10

12

15

11

10

Tr

Tr

Tr

1

Tr

Tr

Tr

Tr

Tr

Tr,

Tr

Tr

Tr

1

13-13-24ddd

1

1

Tr.

-----

----

11 

19 

33

34

36

28 

31

36

40

37

.....

-----

3 

3 

3 

1 

1

1 

Tr. 

Tr. 

2 

Tr

3 

3 

2 

3

2

3

1

2 

2 

2

13

8 

7 

6 

6

5 

5

4 

7 

5

3

2 

2 

1 

Tr.

1

1

\ <s

16 

10 

9

7 

6

6

5 

8

8

1 

1 

1 

Tr. 

Tr.

Tr.

Tr. 

Tr.

3

2 

Tr. 

Tr. 

Tr.

1 

Tr.

Tr. 

Tr.

....--

~Tr~.~~

1

Tr. 

Tr.

57 

62 

54 

54

57

59 

58 

59 

52 

51

30 

28 

30 

31 

30

29 

30 

27 

30 3-'

87 

90 

84

85 

87

88 

88 

86 

82 

83

12 

10 

13 

11 

13

12 

13 

12 

12 

10

- --

1 

Tr.

-----

Tr.

Tr.

-----

-----

Tr. 

Tr. 

1 

Tr.

Tr.

9 

1

6
D20 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

TABLE 4. Light and heavy minerals in the unconsolidated

[Tr.,

Depth (feet)

Heavy minerals (percent)

Opaques

3

1

i

"S 

1

s

§

I3

2

o

Hematit o

I

0H

O

Limonit

3"o

e

Nonopaques

Zircon

1 

0

Yellow Brown a

s

3"o

e

So

A 

a

CQ

Tourm?line

 S

33

S

a

S

Green-b

2

S

"S 

M

r

"§

Hornble

Test hole

60-65------

65-70. ........

70-75-.......-

75-80------

80-85 .

85-90. ........

90-95----..-..

95-100..-..-.

100-105. ..-

110-114.2 -

?,?,

24

oe

14

14

?9

^

?6

99

22

?,7

3

3

?,

4

3

3

1

1

1

1

10

6

11

18

4

9

10

9

8

Tr

Tr

Tr

Tr

Tr

Tr

5

2

Tr

1

1

Tr.

3

36

33

OQ

?7

37

36

4?

45

31

36

?,

7

7

6

4

in

1

1

1

3

Tr,

?:

4

1

1

?,

?:

3

1

?,

9

9

3

4

3

3

Tr.

Tr.

5

11

9

11

6

8

14

IS

15

10

16

Tr.

1

1

1

1

1

Tr.

Tr.

Tr.

Tr.

1

1

1

1

1

2

Tr.

1

3

1

2

Tr.

2

1

2

1

2

3

10

8

g

8

10

13

11

8

7

9

Test hole

2.6-7

7-11. .......

11-15. .......

1.5-19.----...

19-23------

23-27----.-..

27-31--. -.--.

Q1 OK

39-49

42-46------

46-50------

50-51.5.......

51.5-52.5i.....

52.5-54........

99

3*

09

36

18

26

31

35

20

26

?5

?3

1

1

1

1

Tr

1

1

1

1

4

o

9

1

4

3

o

9

4

4

5

7

229?,

Tr

3?

?4

34

40

°1

31

3fi

41

°9

37

03

dQ

47

11

10

15

1?

19

13

10

8

10

9?,

13

7

8

9

6

6

6

4

6

6

3

4

5

6

3

1

9:

3

9

3

2

5

5

5

1

9

1

1

1

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

99

19

93

18

93

94

18

13

19

30

17

19

10

1

1

1

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

4

1

3

4

2

1

3

1

1

3

2

Tr.

1

1

1

9

1

2

2

Tr.

1

1

Tr.

1

17

19

30

18

31

30

°7

96

95

Qfi

18

91

g

1Q

31

Test hole

18-22

22-26... .......

30-34--....-..-

34-38-------

38-42 . ...

42-46. ... ------

46-50-...-.-...

50-54- . ..

54-58.. --------

58-62

62-66--...--

66-70--........

70-721.-.-.--..

72-76-. -

76-80------

80-84--.-.-.-.

84-88-...-.....

88-92

92-94-. ........

"3

31

ti

41

47

24

47

98

35

31

36

?8

16

"0

9

1?

?1

W

1

1

Tr

Tr

1

1

1

2

Tr

1

?

1

1

1

1

Tr

1

1

1

9

2

2

3

4

3

4

1

3

S

18

99

?,7

?3

16

14

Tr

Tr

Tr

Tt

Tr

1

Tr

Tr

Tr

Tr

Tr

95

33

43

49

3°

?9

SI

34

3S

35

43

07

35

43

3fi

37

43

16

14

13

10

10

9

IS

18

11

9

g

11

7

11

4

6

S

5

5

6

5

4

4

4

5

1

1

3

6

4

4

3

3

7

S

4

S

4

4

4

3

5

1

3

4

Tr.

Tr.

Tr.

1

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

1

Tr.

94

°,4

?,n

18

19

?,5

96

?,1

?.7

95

19

17

19

15

13

14

11

?,1 >1

Tr.

1

1

1

Tr.

1

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

1

Tr.

Tr.

Tr.

Tr.

5

4

4

4

3

4

3

9

2

4

3

2

4

4

1

9

1

1

1

1

3

Tr.

1

1

Tr.

2

2

1

1

1

1

1

Tr.

Tr.

1

99

19

90

91

14

19

16

10

?n

13

?,?

?4

98

31

34

34

94

29

1 No sample.
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D21

deposits beneath the Platte River flood plain Continued 

trace]

Heavy minerals (percent) Continued

Nonopaques Continued

-S"o

' §

S

1S

EH

a> 'So 

3

a>

2

&

M

"2"S,

w

g

0

,0"g

"co

"3

«

Garnet

»

o "o

U

 a

PH

a 

o

EH

E>

?

m

0>

"o

3

C3

m

o

C3

a

Light minerals (percent)

Quartz

d '3

fin

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13-13-24ddd Continued

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9
D22 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

in varying degree. Even rather light precipitation can be an effective 

source of recharge if the soil is already moist, vegetation is dormant, 

and humidity is high. Conversely, heavy rain may result in little or no 

recharge if the soil is deficient in moisture, plants are growing rapidly, 

and the evaporation potential is high. The amount of recharge ranges 

widely from year to year and from one part of the area to another 

within the same year.

Most of the valley lands are subject to flooding. Where flooding 

occurs, tJie unconsolidated deposits generally become saturated to the 

land surface, but when the flood water recedes, the water table soon 

lowers to its more usual position owing to the combined effects of 

evaporation, transpiration of vegetation, and subsurface drainage.

The Platte Kiver and the lower reaches of the other streams in the 

area are, in most places, hydraulically continuous with the zone of 

saturation in the unconsolidated deposits. Thus, whenever the stage of 

the river is higher than that of the water table, water percolates out 

of the stream and into the unconsolidated deposits. Because the Platte 

and Elkhorn Rivers and Wahoo and Salt Creeks are never completely 

dry within this area, they are a potential source of rechrrge in any 

reach where, for a time, the adjacent water table is lowered below 

stream level. The quantities of water that move out of the streams 

into the unconsolidated deposits cannot be determined from currently 

available information. It has been variously estimated that more than 

50 percent and possibly as much as 90 percent of the water yielded by 

wells in the Lincoln well field is induced seepage from the Platte 

River.

Inflow from the adjacent bedrock also may be a source of water in 

the unconsolidated deposits. Although, compared to recharge from 

other sources, the quantity of such inflow is likely of little significance, 

it may account for some local differences in the chemical quality of the 

water. Probably, however, differences in the quality of tl Q, water in 

the unconsolidated deposits are due far less to inflow from the bedrock 

than to differences in the mineral composition of the unc-msolidatecl 

deposits through which the water has percolated.

As shown by a water-table-configuration map prepared by Souders 

(1967), the ground water in the Quaternary deposits beneath the terrace plain percolates generally southeastward. Apparently, however, 

none percolates far enough to merge eventually with the underflow 

in the Platte River valley. Instead, part is discharged by evapotranspiration where the water table is within the reach of plant roots, and 

the remainder discharges directly into Clear, Silver, and Wahoo 

Creeks.
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D23

Souders map also shows that the ground water in the area between 

the Platte River valley and Clear Creek percolates south and southsouthwestward. Near the Platte the direction of percolation is nearly 

parallel to the river and farther westward it is toward Clear Creek. As 

pumping at the Lincoln city well field has created a trough in the 

water table, the direction of percolation in the vicinity of the well field 

is toward the axis of that trough. The approximate extent of the area 

throughout which ground water moves toward the well field is indicated by stippling in figure 1.

Elsewhere in the Platte River valley the direction of ground-water 

movement presumably is either parallel to or toward the principal surface drainage channels. Withdrawals for Allied Chemical Corp. and 

evaporation from the several gravel pits excavated below the water 

table result in local deviations from the natural direction of groundwater movement.

GEOCHEMICAL METHODS

A study was made of reactions involving the atmosphere, the 

ground water, and the solid phases identified in the petroryraphic 

study. Also considered was the possibility of reactions with organic 

matter.

The pertinent reaction for the effect of the atmosphere is

co^-oo^. (i)

For any particular concentration of C02(aq) (undissociated carbon 

dioxide in solution) there would be, at any temperature, a partial 

pressure (PCo2) in the gas in equilibrium with the solution. As shown 

by Keeling (1960), the concentration of carbon dioxide in the atmosphere is uniform. For the calculation of the PCo2 in the atmo^here, 

only the barometric pressure (or air temperature and elevation) needs 

to be known. The Pco2 in equilibrium with a water sample may be 

calculated according to the equation

H++HC03-=H20+C02(g) (2)

from Pco2=-KVlO~pH-7Hco3--raHco3-, (3) 

where 7=activity coefficient,

m=molality,

and pH = log aH+> 

where a activity.
D24 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES 

A comparison of the PCo0 in the atmosphere with the Pco in the

+> 2

water sample provides a test for equilibrium.

A test for chemical equilibrium between calcite and coexisting 

water is provided by the following equations:

CaCO3 (calcite)=Ca+2+COr2 (4)

C03-2+H+1 =HC03 - 1 (5)

HCOr'+H+^COa+HaO (6)

H+1 +OH-J =H2O (7)

For reaction 4 the ion activity product, IAP, is defined as

Z4Psac.+»-aco»-a (8)

The activities of the ions were calculated from the concentration of 

the ions by the equation

a =my.

The ion activity coefficients were determined from the Del ye-Huckel 

equation (Klotz, 1950, p. 328-336). The activity of the carbonate ion, 

aco3~2 , is calculated from the equation

«HC03 «HC03

where K% is the equilibrium constant of the second dissociation of 

carbonic acid and its value is a function of temperature. The pH was 

determined by the method described by Barnes (1964). Both pH and 

WHcoa"" 1 were measured in the field to avoid changes that might occur 

during storage. Samples for calcium analyses were acidif ed to preclude losses by precipitation in the sample bottles. Values used for 

the equilibrium constants of equations 4, 5, and 6 are from Larson 

and Buswell (1942, p. 1673), Earned and Scholes (1941, p. 1706), and 

Harned and Davis (1943, p. 2030), respectively.

The equilibrium constant, -5TCaicite, for reaction 4 can be compared 

with the ion activity product, IAP, for the same reaction to test for 

saturation with respect to calcite. At any temperature, a solution is saturated if the IAP equals -ZTcaicite, unsaturated if IAP/Kca i cit <, is less 

than 1, and supersaturated if IAP/Kc& \ c ne is more than 1.

The ion activity products of reactions for the solution of dolomite, 

calcite, aragonite, magnesite, and gypsum can be calculated by a computer program of the U.S. Geological Survey. Accurate data as to the 

pH of the water, temperature of the water, barometric pressure at 

time of analysis, and concentrations of the major ions in solution 

(especially calcium, carbonate, and bicarbonate ions) are necessary 

if the results are to be meaningful. Because calcite is the only carbonate mineral found in the unconsolidated deposits, the saturation 

of the water was considered only in terms of calcite.
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D25

Water from 10 wells on the terrace plain, 42 wells on the Platte 

River flood plain, and one location on the Platte River was sampled 

during this investigation; of the 42 wells on the Platte River flood 

plain, 33 were in the Lincoln city well field (fig. 3). Dissolved oxygen 

analyses were made in the field. The other chemical constituents (calcium, magnesium, sodium, potassium, sulfate, and chloride) w?,re determined in the laboratory.

GEOCHEMICAL INTERPRETATIONS

GROUND WATER BENEATH THE TERRACE PLAIN

The water from each of the 10 wells on the terrace plain was unsaturated with respect to calcite, the most probable IAP/Kca,i cits 

values ranging from 0.141 to 0.881 (table 5). Although water from

TABLE 5. Selected properties and constituents of ground water beneath the terrac

plain

Well

13-9-6dbc_-

14-8-lcac 

Idee--

2caa.-

23daa.

14-9-17dda.

IScbc.

19daa.

20add.

34bbd.

Ternperature

55.0

56.7

55.9

57.7

54.7

54.9

55.6

54.0

55.8

54.0

Pco2 

(most probable value)

pH Atmos- Ground 

phere water 

(atmX (atmX

7.21

7.14

7.29

7.13

7.01

7.11

7.00

7.09

6.98

7.11

10-3)

0.29

.29

.29

.29

.29

.29

.29

.29

.29

.29

10-3)

8.97

19.5

13.5

22.0

17.6

15.5

25.7

16.4

18.1

10.9

Dissolved ^a-- r>o42

CO 2 (ppm) 

(ppm)

19.28

40.80

28.59

45.23

38.13

33.47

54.77

35.98

38.58

24.02

42

76

103

84

50

63

80

62

57

46

IA.

Maximum

0.204

.543

.968

.671

.187

.335

.392

.296

.211

.157

r /-/tcalci

Minimum

0.165

.443

.791

.548

.145

.237

.320

.219

.134

.121

itDisIC\ . 2 c-nlirrt/1

Most (ppm) 62 

prob- (ppm) 

able

value

0.185

.497

.881

.616

.167

.285

.359

.258

.171

.141

25

36

122

36

27

45

46

43

55

64

6.8

1.4

1.3

.0

3.9

3.4

.7

2.4

5.7

5.8

well 14-8-1 dec approached saturation with respect to calcite, the 

maximum IAP/Kc& i cite for all the other samples was 0.671. The unsaturation with respect to calcite could be expected because cp.lcite is 

such an uncommon constituent of the unconsolidated deposits within 

the zone of saturation beneath the terrace plain. If generally present 

in the unconsolidated deposits earlier, the calcite has been leached from 

them in the meantime.

No areal pattern of variation of IAP/Kc& i clie was apparent, possibly because too few samples were collected. Factors that ma^ affect 

the ratio are differences in the permeability and mineral composition 

of the unconsolidated deposits, in type of soil, and in vegetation. If 

consideration is given to each of these, it is not surprising to find 

variation in the properties of the ground water.
D26 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

The calcium concentration ranges from 42 to 103 ppm (parts per 

million) and generally increases as IAP/Kca.i ci t e increases. Because 

the water-bearing unconsolidated deposits beneath the terrace plain 

contain almost no calcite or other calcium carbonate minerals, the 

major source of calcium ions in the ground water protably is the 

unsaturated deposits through which recharge to the zone of saturation 

must filter. These unsaturated deposits consist largely of loess, which 

still is calcareous at depth even though its upper part is leached deeply 

throughout much of the area. Solution of calcium carbonate in the 

loess by infiltrating water may be sufficient to account for much of 

the calcium in the ground water. Low values of /^.P/Z^caicite may 

reflect recharge through loess from which most of the calcite has been 

leached, and high values may reflect recharge through loess that has 

not been leached so deeply.

As the unconsolidated deposits beneath the terrace plain are in 

direct contact with water-bearing Cretaceous sandstones, inflow from 

those rocks possibly could account for some of the dissolved minerals 

in the water from the sampled wells. However, the chloride content of 

water in the Cretaceous sandstones generally is moderately high, 

whereas the maximum in the samples was only 14 ppm. Therefore, 

either inflow from Cretaceous sandstones is insignificant in amount 

or, if significant, the water in the Cretaceous sandstones is much less 

saline in this vicinity than elsewhere. None of the water in the unconsolidated deposits beneath the terrace plain has been in contact with 

Pennsylvania!! limestones or shales, so no part of the dissolvedmineral content can be attributed to that source.

Table 5 shows that the PCo2 in the ground water beneath the terrace 

plain was 30 to 90 times greater than the pcoa in the atmosphere and 

that the maximum dissolved oxygen in the ground water was 6.8 ppm. 

~No relation was apparent between the PCo2 and dissolved oxygen in 

the water. Possibly the PCo2 in the ground water can be attributed to 

absorption of carbon dioxide by infiltrating water. Generally carbon 

dioxide is produced and concentrated in the soil by a variety of plant 

and microbiologic processes. Baver (1956, p. 199-223) reported a 

definite increase of carbon dioxide with depth and a corresponding 

decrease of oxygen in the air of most soils. The fact that no relation 

was found between oxygen and carbon dioxide in this study supports 

the view that the source of carbon dioxide is probably biologic activity 

such as respiration by plant roots rather than the decay of organic 

matter. Decay reactions not only produce carbon dioxide but also 

consume oxygen.

The concentration of the sulfate ion in ground water fnm beneath 

the terrace plain ranged from 25 to 122 ppm; water from well
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D27

14r-8-ldcc had the only sulfate concentration in excess of 64 ppm 

(table 5). An areal pattern of sulfate concentration is not apparent. 

As no sulfate or sulfide minerals were found in the test-hole simples 

that were examined, it is thought that organic compounds or sulfurbearing minerals in the loess or soil may be the source of the sulfate 

ions in the ground water.

GEOUND WATEE BENEATH THE PLATTE EIVEE FLOOD F^AIN

The most probable values of IAP/Kca i oi te for water from the 33 

wells in the Lincoln city well field ranged from 0.188 to 1.08 and averaged 0.548; for water from the nine downvalley wells the most 

probable values ranged from 0.352 to 1.29 and averaged 0.841 (table 

6). Water that was nearly saturated or supersaturated with respect 

to calcite was yielded by only two wells in the well field, bnt was 

yielded by five of the downvalley wells. It is of special interest that 

the river water (table 7) differs from the water yielded by the city 

wells in that it is about 10 times supersaturated with respect to 

calcite, contains much less dissolved carbon dioxide, and has a significantly higher pH than the average for water from the city wells.

As a large fraction of the water pumped at the well field probably is 

derived from the river, it is surprising that the chemical quality of 

the water from the wells is not more like that of the river water. In 

fact, one might wonder whether the fraction of river water in the 

yield of the wells is actually much less than is indicated by other 

evidence.

Obviously, the IAP/Koa.i oiie values for water naturally in the 

aquifer at this location must be rather low, as the value for water 

from one well was only 0.188 and for water from 11 others was less 

than 0.5. Low values would be expected because limestone fragments 

in the water-bearing material at this location are rather uncommon 

(see log of test hole 13-9-24ddc) and a loess mantle (such as is present 

on the terrace plain) that could be a source of calcium ions is lacking.

As the dissolved carbon dioxide content of water from six of the 

city wells exceeded 20 ppm, it seems reasonable to assume tl^at the 

water naturally in the aquifer generally contains that much or more. 

Infiltrating precipitation, which has dissolved carbon dioxide from 

the atmosphere and from the soil, is the most likely source of the 

carbon dioxide in the ground water. The lowest concentration of carbon 

dioxide in water from the city wells was more than four times that in 

the river water. The average Pco2 in the water from the wells was nearly 10 times that in the river water.

Seven of the city wells yielded water having a pH less than 7.3, so 

the average pH of the water naturally in the aquifer probably is no
TABLE 6. Selected properties and constituents of ground water ben

[Values for total iron determined by city of Lincoln. All measurements are for J

Well

Temperature

 ^ O2 I

(most probable value)

pH 

Atmosphere Ground i 

(atmXIO-3) water i 

(atmXIO-3)

)issolved 

CO2 

(most Ca+2 

) rob able (ppm) 

ralue, in 

ppm)

Maximum

P/JT»l.it.

Mini- Mos

mum probab

valu

Lincoln city well field at Ashland

32.1-. 

32.1A 

32.2 

32.2A. .

32.3

32.3A.... .

32.4. 

32.4A.. ...

32.5

49.6 . 

49.7-.. -..

49.8

49.9. 

54.1 

54.2 

54.3. 

54.4 

54.5

54.6 

54.7 

54.8. 

54.9---- .

54.10 . 

54.11.... _ .

56.1-. _ 

56.2. 

56.3__ 

56.4...- -.

56.5.. 

56.6

56.7 . 

56.8. 

56.9

54.0

54.3

57.6

58.1

57.9

59.0

57.7

56. 1

53. 6

54. 3

53.6

55.4

52.3

55.0

50. 7

53.8

54.7

52.3

55.6

54.1

57. 2

59.5

55. 6

53.8

66.2

50. 0

60.3

55.0

61.3

54.7

7.21 

7.87 

7.08 

7.53 

7.60 

7.54 

7.21 

7.36 

7.28 

7.33 

7.54 

7.60 

7.64 

7.47 

7.57 

7.62 

7.68 

7.68 

7.53 

7.44 

7.76 

7.52 

7.80 

7.31 

7.71 

7.35 

7.45 

7.69 

7.65 

7.68 

7.23 

7.25 

7.28

0.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29 

.29

10.2 

2.08 

13.1 

4.67 

3.98 

4.60 

9.83 

7.15 

8.68 

9.45 

4.34 

5.34 

3.73 

5.06 

4.31 

3.72 

3.21 

3.39 

4.73 

6.10 

2.56 

4.63 

2.41 

8.04 

3.16 

9.70 

6.00 

3.34 

3.40 

3.35 

9.65 

8.79 

8.67

22.37 

4.53 

26.92 

9.51 

8.13 

9.22 

20.14 

15.07 

19.13 

20.56 

9.58 

11.57 

7.96 

11.42 

9.72 

8.00 

7.46 

7.46 

10.74 

13.19 

5.79 

9.85 

5.27 

16.63 

6.27 

20.62 

13.19 

5.94 

8.01 

6.57 

20.72 

16.94 

18.75

54 

48 

54 

53 

54 

56 

55 

55 

59 

73 

55 

79 

56 

50 

55 

50 

51 

56 

54 

57 

51 

52 

49 

56 

52 

74 

61 

50 

54 

53 

58 

54 

60

0.274 

1.22 

.207 

.596 

.731 

.648 

.294 

.430 

.361 

.564 

.543 

1.22 

.800 

.417 

.622 

.678 

.645 

.815 

.534 

.500 

.800 

.536 

.881 

.386 

.957 

.694 

.634 

.988 

.633 

.939 

.309 

.341 

.355

0.223 

.717 

.168 

.484 

.566 

.527 

.239 

.318 

.266 

.459 

.441 

.949 

.621 

.323 

.460 

.477 

.525 

.663 

.414 

.407 

.650 

.415 

.716 

.314 

.742 

.540 

.370 

.803 

.515 

.694 

.251 

.277 

.289

0.2

.94

.1

.5

.64

.5

.2

.3

.3

.5

.49

1.0

.70

.37

.54

.57

.58

.73

.47

.45

.72

.47

.80

.35

.85

.61

.48

.89

.57

.81

.28

.31

.32
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D29

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D30 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

greater than that value. The river water has a pH of about 8.5, or more 

than one unit higher.

If the river water normally is as supersaturated with respect to 

calcite as the values for IAP/Kca.i cite indicate it to be, a large decrease 

in degree of supersaturation occurs during transit of the water from 

the river to the city wells. The specific factors involved in this decrease 

are not known but probably are related to environmental change. 

Water that had been flowing freely must now follow a tortuous path 

through intergranular openings, and, compared to the rate of riverflow, its rate of percolation through the aquifer is very slow. Moreover, 

the conditions of temperature and pressure are not the same, and the 

water comes into contact with a variety of minerals. Eventually the 

water derived from the river becomes mixed with water raturally in 

the aquifer.

Deposition of calcite on the grains of the material through which 

the river water must percolate to reach the wells could account for 

the decrease, but then the similar values for concentration of calcium 

in the river water and in water yielded by the wells would ne^d to be explained. The decrease in degree of saturation most likely involves addition of carbon dioxide to the water, and such addition would account 

for the well water having a lower pH than the river water. Whether 

the difference in the dissolved carbon dioxide values for the river water 

and the assumed average for water naturally in the aquifer is a significant factor in the change from supersaturation to unsaturr.tion is not 

known. Before the change can be explained satisfactorily, the seasonal 

range in values of IAP/Kca.i ci te for the river water and the areal range 

in values of /AP//rca i clte for ground water moving toward the well 

field need to be determined.

The distribution of the IAP/KC!i i ci t e values for water from wells 

in the Lincoln city well field is shown in figure 4. Instead of indicating 

a progressive decrease with distance from the river, the distribution 

of the ratio lacks obvious pattern and thus probably is a function of 

more than a single factor. Heavy pumping undoubtedly l^s altered 

the natural paths and rate of ground-water travel, and pumping at 

different rates at different times in different parts of the well field 

probably precludes establishment of a fixed new pattern of flow paths. 

Furthermore, the permeability of the water-bearing materials through 

which water percolates from the river to the well is not uniform, so 

the routes of least resistance to water movement may be mere devious 

than direct.
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D31

13

EXPLANATION

49-8 

O I.J

Ground-water sampling

site

Upper number is well designation; lower number is 

IAP/Kcaicite on October 

11, 1963

8.37 

A 10.8

Surface-water sampling 

site

Numbers are IAP/K calcite 

on October 11, 1963. 

Upper number, early 

morning; lower number, 

early afternoon

FIGURE 4. Distribution of e values, Lincoln city well field.
D32 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

The data on dissolved oxygen and dissolved iron (figs. 5, 6) show 

some interesting relationships. The two constituents are not compatible, as shown by the stepwise reactions

O2 -f4H+-f4e-=2H2O

4Fe+2=4Fe+3 -|-4e4Fe+3 -H2H2O=4Fe(OH) 3 -H2H+ 

which, when added, give

02 -HFe+2 -HOH2O=4Fe(OH) 3 4-8H+,

the last reaction being a summary statement of the oxidation of the 

dissolved iron and precipitation of a ferric hydroxide. (More detailed 

discussions are presented by Hem and Cropper (1959) and Hem 

(I960).) The hydroxide dehydrates on aging, so it would be expected 

that wells yielding water containing both dissolved iron ard dissolved 

oxygen wrould become encursted with various hydrated iron oxides 

and that over a period of years the yield of the wells would decline.

Generally, wells discharging water containing both iron and oxygen 

in solution are drawing water from two sources one a body of ground 

water containing dissolved oxygen and negligible dissolved iron and 

the other a body of ground water containing dissolved iron and negligible dissolved oxygen. The former probably is the induced seepage 

from the river and the latter the water naturally present in the aquifer. 

To reach the wells, river water percolates only a short distance through 

the aquifer and moves at a fairly fast rate owing to the l x <>avy withdrawal by pumping. Although it loses some of its dissolved oxygen in 

transit, it has little opportunity to dissolve more iron before it is 

mixed, when entering the wells, with water derived from that naturally 

in the aquifer. On the other hand, most of the ground water naturally 

in the aquifer is derived from precipitation that has passed through 

sediments containing organic matter; furthermore, it has- traveled a 

considerably longer distance at a much slower rate througv sediments 

containing pyrite and hematite and so has had greater opportunity to 

dissolve iron as it approached the well field. The differences in total 

iron concentrations (table 6) with time may reflect changes in the 

proportion of water derived from the two sources.

As indicated in table 7, one of the samples of Platte Piver water 

was collected in the early morning and the other in the early afternoon 

of October 11,1963. The concentration of dissolved oxygen in the river
WATER-MINERAL RELATIONS, LOWER PLATTE ABEA, NEBRASKA D33

13

y EXPLANATION

56-9

Ground-water sampling

site

Upper number is icetl designation; lo we r numbe r is 

dissolved oyygen concentration, in parts per 

million, on October 11, 

1963

8.8 

A 10.;

Surface-water sampling

site

Numbers are dissolved oxygen concentration, in 

parts per million, on 

October 11, 1963. Upper 

number, early morning; 

lower number, early 

afternoon

FIGURE 5. Distribution of dissolved oxygen concentrations, Lincoln

city well field.
D34 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

13

EXPLANATION

54-n 

o ao2

Ground-water sampling

site

Upper number is well designation; lower number 

is dissolved iron concentration, in parts per 

million, on October 11,

0.02

Surf ace-water sampling site

Number is dissolved iron 

concentration, in parts 

per million, on October 

11, 1963

FIGURE 6. Distribution of dissolved iron concentrations, Lincoln city

well field.
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D35

water was lower in the early morning owing to respiration of organisms and higher in the afternoon owing to photosynthesis. That the 

controlling factor was biologic is indicated by the temperature variations, the dissolved oxygen being lower at a lower water temperature; 

the controlling factor could not be inorganic because solubility of 

oxygen increases with decreasing temperature. Even the lower of the 

two values for the concentration of dissolved oxygen in the river water 

was much higher than the values for the concentration of dissolved 

oxygen in the ground water.

The samples of water from wells downvalley from the well field 

probably contain little or no water derived from the Platte Eiver and 

so are representative of water naturally in the aquifer in that reach 

of the valley. The higher average concentration of calcium in the 

water and the higher average value of IAP/K ca icite probably are 

related to the greater abundance of caicite in the water-bearing sediments in this reach compared to the well-field vicinity. The generally 

lower values of dissolved oxygen in the water probably are explained 

by the lack of water derived from the river. No other significant differences between water from the city wells and from wells downvalley from the well field were noted.

SUMMARY

Environmental conditions are reflected by the chemical quality of the 

ground water contained in Quaternary sand and gravel aquifers within 

the lower Platte River drainage basin.

In the terrace-plain area in southeastern Saunders County, tl 3 sand 

and gravel aquifer is mantled by a thick deposit of loess, and the 

principal source of recharge to the aquifer is local precipitation that 

infiltrates the loess. Even though the sand and gravel aquifer contains 

little or no caicite or sulf ate minerals, the ground water contains both 

calcium and sulfate in solution. Furthermore, the PCo2 in the water is 

many times greater than the PCoz in the atmosphere and is generally 

greater than in the ground water in the other two areas. Although the 

upper part of the loess is leached, the lower part is calcareous and so 

may be the principal source of the calcium ions. Similarly, organic 

compounds or sulf ate-bearing minerals in the soil or loess may be the 

source of the sulfate ions. Respiration by plant roots and other biologic 

activity in the upper part of the loess probably account for most of the 

carbon dioxide in the water.

In the Lincoln city well field in the Platte River valley near Ashland, no loess overlies the sand and gravel, and recharge from p ^ecipitation enters the aquifer almost directly. As pumping induces seepage 

from the Platte River, the water yielded by the wells is a blend of
D36 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

water naturally in the aquifer and of water derived from the river. 

Kather large differences in degree of saturation with respect to calcite 

were detected, and the water from two of the 33 sampled wells was close 

to saturation. That more of the water was not saturated with respect to 

calcite is surprising in view of the river water being eight to ten times 

supersaturated. Possibly the great decrease in degree of saturation 

results from calcite deposition before the river water reaches the wells. 

Significantly, however, the average concentration of calcium ions in 

the water yielded by the wells was nearly the same as that in the river 

water. It was noted that water from many wells contained more dissolved iron than the river water; furthermore, the water from the wells 

also contained dissolved oxygen, which is not compatible with dissolved 

iron in the same solution. Water naturally in the aquifer probably 

contains dissolved iron, and the river water is known to contain dissolved oxygen; the water from one source probably has little or no 

opportunity to mix with the water from the other source before entering the wells. As the carbon dioxide content of the water yielded by 

the wells was much higher than that of the river water, the water 

naturally in the aquifer must be the source of carbon dioxide. Different 

proportions of water from the two sources probably account for the 

differences in the chemical quality of the water yielded by different 

wells.

Of the nine sampled wells on the Platte River flood plain downvalley 

from the well field, five yielded water either nearly saturated or slightly 

supersaturated with respect to calcite. Pebbles and larger fragments 

of limestone, which are abundant in the aquifer in this area, are a 

likely source of the calcium ions.

LOGS OF TEST HOLES

Test holes were drilled as part of the ground-water studies made cooperatively by the Conservation and Survey Division of the University of Nebraska and the U.S. Geological Survey. Samples of the cuttings may be examined at the Conservation and Survey Division.

Test hole 13-9-24ddc: _ .. Depth Quaternary deposits: (feet)

Soil, silty, calcareous, gray; some sand and clay _ __ 9.6-12.4 

Sand, medium to coarse, tan to brown; abundant feldspar; soir^

silt and clay lenses below 20 ft__________________ 12.4-23.2 

Silt, sandy, dark-gray_________________________ 23.2-23.5 

No sample________________________________ 23.5-25 

Sand, coarse, brown; some siliceous root fragments; some gravel

and silt_________________________________ 25-35 

Sand, medium to coarse, tan; abundant feldspar; siliceous root

fragments _______________________________ 35 55
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D37

Test hole 13-9-24ddc Continued Depih 

Quaternary deposits Continued (feet) 

Sand, medium to coarse, tan; increasingly gravelly with depth;

some limestone fragments; silty from 70 to 80 ft 55-84.5 

Pennsylvanian rocks:

Shale, clayey, fossiliferous, gray to green _ 84.5-? 

Test hole 13-ll-36dad: 

Quaternary deposits:

Soil, silty, slightly calcareous, gray to brown; contains some sand

and sparse orthoclase pebbles _ 0.4-1.5 

Sand, medium to coarse, tan to brown; grades downward to 

coarse sand containing 5-10 percent gravel; clay and silt lenses 

between 20 and 25 ft__________________ 1.5-25 

Sand, coarse, brown; contains 25 percent gravel; some siliceous

and calcareous nodules; sparse orthoclase and quartz pebbles 25-50 

Sand, coarse, brown, and some gravel; some siliceous and calcareous nodules___ _ _ _ 50-80 

Gravel, tan to brown; predominantly orthclase and quartz; some

rock fragments________ ___________________ 80-95 

No sample; probably Pennsylvanian rocks __ _ _-___ 95-100 

Test hole 13-13-24ddd: 

Quaternary deposits:

Soil, silty with some clay, gray to brown; increasingly sandy with

depth; slightly calcareous and ferruginous with depth__ 0-10 

Sand, fine to medium, brown to gray; abundant dark minerals__ 10-30 

Sand, fine to coarse, tan to brown; some gravel_________ 30-40 

Sand, fine to coarse, tan to brown; contains some gravel and limestone fragments; some silt and clay lenses below 45 ft_____ 40-58 

Sand, fine to medium, brown to gray; some gravel, mostly quartz

and feldspar; a few limestone fragments____________ 58-65 

Sand and gravel, tan; abundant feldspar fragments; some siliceous nodules_____________________________ 65-100 

Gravel, tan; abundant feldspar and rock fragments; crinoid 

stem _ _ ______________ 100-110

Sand, coarse, yellowish-tan; some gravel; 10 percent limestone 

fragments _ ____ __________________ 110-114.2

Test hole 13-13-29db: 

Quaternary deposits:

Soil, silty with some clay, dark-brown; noncalcareous______ 0-2. 6 

Sand, medium to coarse, tan; scattered quartz and orthoclase

pebbles; limestone fragments below 31 ft____________ 2.6-35 

Sand and gravel, tan; gravel contains orthoclase and quartz pebbles and scattered limestone fragments_____________ 35-46 

Gravel, tan; contains orthoclase and quartz pebbles and limestone fragments __________________________ 46-51.5 

No sample_______________________________ 51.5-52.5

Gravel, light tan; 20-30 percent limestone fragments______ 52.5-54.5 

Pennsylvanian rocks: 

Shale, clayey, gray; maroon inclusions_______________ 54.5-?
D38 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

Test hole 13-13-32ad: _ 47

~ ^ Depth Quaternary deposits: (feet)

Soil, silty, noncalcareous, brownish-gray; some clay and sand 0. 5-1. 5 

Silt, clayey and sandy, calcareous, brownish-gray__ _ 1. 5-15 

No sample____________ _ ___ _ _ 15-18

Sand, medium to coarse, tan; increasingly gravelly with depth; 

some silt and clay lenses____________ ___ _ 18-42

Sand, medium to coarse, tan; limestone cobbles below 50 ft_ 42-62 

Sand and gravel, tan ; scattered limestone cobbles__ __ 62-70 

No sample__________________________________ 70-72 

Gravel, tan to brown ; some coarse sand; scattered limestone ani

rock fragments______________________________ 72-94 

Pennsylvanian rocks:

Shale, clayey, slightly calcareous; yellowish brown grading dowrward to green gray___________________________ 94-98 

Test hole 14-8-23ccc:

Soil, tan, silty; includes small amount of clay; leached _, 1. 0-1. 5 

Loess, silty, calcareous, friable, tan___________________ 1. 5-8. 8 

Sand, fine to coarse, gravelly with depth, tan; contains siliceous 

root fragments ; silt and clay lenses from 56 to 65 ft__________

Sand, fine to coarse_ ___ _ _ _ __________

Sand and gravel, tan; gravel fraction increases from 10 to 40 percent with depth; mostly orthoclase and quartz__________ 80-95 

Gravel, predominantly feldspar and quartz; some coarse sand;

some rock fragments coated with Fe2Os from 105 to 108.9 ft__ 95-108. 9 

Test hole 14-9-20ddd:

Soil, silty, brown; little organic material_______________ 0-0. 5 

Soil, silty, tan, leached__________________________ 0. 5-5 

Loess, silty, tan, friable; somewhat calcareous from 7 to 16 ft_ 5-16 

Sand, fine to coarse, tan; increasingly coarser with depth; 5 percent gravel from 56 to 61 ft; siliceous root fragments throughout _____________________________________ 16-61 

Sand, fine to coarse_______ _ _____ _ ___ _ 61-95

Sand and gravel, brown; considerable well-rounded orthoclase; 

siliceous root fragments from 95 to 101 ft; broken Ironstone 

fragments (Cretaceous?) from 106 to 110 ft___________ 95-110 

Cretaceous rocks:

Sand, fine, yellow-tan; apparently unoemented__ ___ 110-? 

Test hole 14-9-30ddd:

Soil, silty, dark-gray, leached______________________ 0-2

Loess, silty, slightly calcareous, buff, friable____________ 2-12. 5 

Sand, fine to medium, tan; coarser with depth; contains siliceous

root fragments____________________________ 12. 5-60 

Sand, fine to medium_________________________ 60-75 

Sand and gravel, tan; gravel mostly quartz and orthoclase-___ 75-86

REFERENCES

Barnes, Ivan, 1964, Field measurement of alkalinity and pH: U.S. Geol. Survey

Water-Supply Paper 1535-H, 17 p. 

Baver, L. D., 1956, Soil physics: New York, John Wiley & Sons, Inc., 489 p.
WATER-MINERAL RELATIONS, LOWER PLATTE AREA, NEBRASKA D39

Harned, H. S., and Davis, Raymond, 1943, The ionization constant of carbonic

acid in water and the solubility of carbon dioxide in water and aqueous salt

solutions from 0° to 50°C: Am. Chem. Soc. Jour., v. 65, no. 10, p. 203V2037. 

Harned, H. S., and Scholes, S. R., Jr., 1941, The ionization constant of HCOr

from 0° to 50°C: Am. Chem. Soc. Jour., v. 63, no. 6, p. 1706-1709. 

Hem, J. D., 1960, Restraints on dissolved ferrous iron imposed by bicarbonate,

redox potential, and pH: U.S. Geol. Survey Water-Supply Paper 1459-B,

p. 33-55. 

Hem, J. D., and Cropper, W. H., 1959, Survey of ferrous-ferric chemical equilibria

and redox potentials: U.S. Geol. Survey Water-Supply Paper 1459-A, p. 1-31. 

Keeling, C. D., 1960, Measurements of carbon dioxide in the atmopsher?: Am.

Geophys. Union Trans., v. 41, no. 3, p. 512-515. 

Klotz, I. M., 1950, Chemical thermodynamics: New York, Prentice-Hall, Inc.,

368 p. 

Larson, T. E., and Buswell, A. M., 1942, Calcium carbonate saturation indQx and

alkalinity interpretations: Am. Water Works Assoc. Jour., v. 34, no. 11,

p.1667-1684. 

Souders, V. L., 1967, Availability of water in eastern Saunders County, Nebraska:

U.S. Geol. Survey Hydrologic Inv. Atlas HA-266.

U.S. GOVERNMENT PRINTING OFFICE: 1961