GEOLOGICAL SURVEY CIRCULAR 107

June 1951

PROGRESS REPORT

CHEMICAL QUALITY OF THE SURFACE WATERS

IN THE 

LOUP RIVER BASIN, NEBRASKA

By

John G. Connor

Compiled as part of the Interior Department program 

for development of Missouri River basin
UNITED STATES DEPARTMENT OF THE INTERIOR

Oscar L. Chapman, Secretary

GEOLOGICAL SURVEY

W. E. Wrather, Director

WASHINGTON, D. C.

Free on application to the Director, Geological Survey, Washington 25, D. C.
CONTENTS

Page Page

Abstract ---------------- l Quality of the water ---------- 3

Introduction -------------- l Qeochemlcal relationships and salinity

Physical and geological characteristics ----------- 3

description -------------- l Quality of water in relation to use - 12

Methods of analysis ---_-_--__ 3 Summary ---------------- 15

	List of references ----------- 15

ILLUSTRATIONS

Page 

Plate 1. Views of the Middle Loup River: A, Sampling station at Dunning* from right bank;

B, View across river below DunnTng ----------------------- 2

2. A,"~Hydrograph of Middle Loup River at Dunning, January 1947-September 1948; B^

Hydrograph of Middle Loup River at St. Paul, January 1947-September 1948 - - - - 6

3. A, Hydrograph of South Loup River at St. Michael, January 1947-September 1948;

~~ B, Hydrograph of North Loup River near St. Paul, January 1947-September 1948 - - 6

4. A,~Hydrograph of Cedar River near Spalding, January 1947-September 1948; B,

Hydrograph of Beaver Creek at Loretto, January 1947-September 1948 ------- 6

Figure 1. Map of the Loup River basin showing sampling stations for quality of water

studies ------------------------------------ 2

2. Mineral constituents during high, average, and low flow main stem, Loup River

basin -_----__----____-_-__----_----_-_-_-- 6

3. Mineral constituents during high and low flow--major tributaries, Loup River

basin --------------..---------.----------. 7

4. Mineral constituents during high and low flow minor tributaries, Loup River

basin -_-_______-______-_____-__-__--_----_ 8

5. Oeochemlcal classification of Loup River waters ----------------- 11

6. Percentage of reacting value of several major ions, Middle Loup River at

St. Paul ------------------------------------ 13

7. Trends in content of silica in waters, Loup River basin ------------- 14

TABLES

Page 

Table 1. Mineral constituents and related physical measurements for sampling stations on

the main stem, Loup River __---___------------------- 4

2. Mineral constituents and related physical measurements for sampling stations on

tributaries to the Loup River ------------------------- 5

3. Comparative hydrologic information for the Loup River and its tributaries - - - - 9

4. Percentages of reacting values of ions for waters In the Loup River basin - - - - 10

5. Permissible limits for electrical conductance, percent sodium, and boron in

several classes of irrigation water ---------------------- 12

6. Classification for irrigation use of Loup River streams during high and low

discharges ----------------------------------- 12
PROGRESS REPORT 

CHEMICAL QUALITY OF THE SURFACE WATERS

IN THE 

LOUP RIVER BASIN, NEBRASKA

' By

John 6. Connor

ABSTRACT

The Loup River and its tributaries transport moderate amounts of siliceous minerals 

from the sand hills region of north-cen-tral 

Nebraska to the Platte River near Columbus, 

Nebr. Predominant chemical characteristics 

of these waters are a high percentage of silica, moderate hardness, and a low percentage 

of sodium. The composition of the Loup River 

water is influenced by the geologic formations through which ground water, a major 

contributor to the flows of the Loup River 

branches, has percolated.

Investigation of water quality at or near 

proposed dam sites in the Loup River basin 

indicates that if soil and drainage conditions are favorable, the impounded water 

would be satisfactory for irrigation use.

INTRODUCTION

Because of a possible expansion of the use 

of water for irrigation in the Loup River 

basin, Nebr., by construction of proposed 

dams near Dunning, Boelus, Cotesfield, Erickson, and Loretto, an investigation of the 

quality of surface water in this basin began 

in March 1947 as part of a comprehensive 

water-resources study of the Missouri River 

basin by the United States Geological Survey.

Sampling points in the Loup River basin 

were selected to obtain the best geographical 

coverage of the region so that the quality of 

the water could be properly determined. (See 

fig. 1 and pi. 1.)

During the period March 1947 to September 

1949, samples were collected periodically at 

seven stations in the basin and analyzed by 

the Geological Survey.

This study was made under the general direction of S. K. Love, Chief, Quality of 

Water Branch, Geological Survey, and under 

the supervision of P. C. Benedict, regional 

engineer, in charge of quality-of-water investigations in the Missouri River basin. 

Analyses of samples collected for this report 

were made by W. M. Barr, Robert Brennan,

H. 0. Bush, M. B. Florin, R. H. Langford, 

R. P. Orth, P. H. Rainwater, L. L. Thatcher, 

and J. C. Thompson.

PHYSICAL AND GEOLOGICAL DESCRIPTION

The Loup River basin, resembling an elm 

leaf in shape, is in central Nebraska. It 

has an area of 15,724 square miles or about 

one-fifth the area of the State. (See fig. 

1.) The basin is 325 miles in length and 80 

miles at its widest point and narrows to 4 

miles in width at its confluence with the 

Platte River.

The Loup River flows in -a general southeastward direction and empties into the 

Platte River just below Columbus, Nebr. 

Three main branches the Middle Loup, the 

South Loup, and the North Loup Rivers converge to form the Loup River proper. The 

Middle Loup River, which is considered to be 

the main stem, is joined by the South Loup 

approximately 4 miles northeast of St. 

Michael and by the North Loup 4^ miles east 

of St. Paul, Nebr. The principal tributaries 

are the Dismal River, the Calamus River, the 

Cedar River, and Beaver Creek. The Dismal 

River joins the Middle Loup River near 

Dunning; the Calamus River enters the North 

Loup River near Burwell; the Cedar River and 

Beaver Creek join the Loup River downstream 

from St. Paul. A canal 25 miles upstream 

from Columbus diverts most of the normal flow 

of the Loup River for generation of hydroelectric power.

Geologically, the Loup River basin is blanketed by loess and dune sand, which are 

underlain by bedrock at varying depths. 

Loess overlies the southeastern one-third of 

the basin, and dune sand covers the remainder 

of the basin. Alluvium is present along all 

the larger drainage ways.

The sandy soil readily absorbs rainfall and 

stores large quantities of water in underground reservoirs. These reservoirs feed the 

streams of the basin through various underground routes and are effective in stabilizing stream flows. Precipitation records show 

that the upper half of the basin lies in a
101

Legend

A Sampling station 

 Town

10 0 10 20 30 40 MILES 93

Figure I. Map of the Loup River basin showing sampling stations for quality 
GEOLOGICAL SURVEY CIRCULAR 107, PLATE 1

A. Sampling station at Dunning, from right bank

B. View across river below Dunning

VIEWS OF THE MIDDLE LOUP RIVER
flood-producing storm area; however, the area 

has very little runoff because of the pervious mantle rock.

METHODS OP ANALYSIS

The analyses of samples collected in 1943 

include results for specific conductance, pH, 

sodium, bicarbonate, sulfate, chloride, nitrate, and calculated total hardness. Analyses for samples collected since November 1, 

1945, include the following determinations: 

specific conductance, pH, dissolved solids, 

silica, iron, calcium, magnesium, sodium, 

potassium, bicarbonate, sulfate, chloride, 

fluoride, nitrate, boron, percentage of sodium, total hardness, and noncarbonate hardness. 

For one sample, sodium and potassium were reported separately, and for the remaining samples, sodium and potassium were calculated 

and reported as sodium.

All analyses were made by methods commonly 

used by the Geological Survey (Collins, 1928 

and Am. Public Health Assoc., 1946).I/ Boron 

was determined by an electrometric method, on 

the basis of methods developed by Poote and 

Wileex (1932).

QUALITY OP THE WATER

An indication of the acceptable quality of 

the Loup Basin streams may be seen in tables 

1 and 2, in which the mineral constituents of 

the water samples are expressed in parts per 

million. The water was hard and siliceous; 

the range in hardness and silica of 44 samples collected during high, medium, and low 

stages was 62 to 198 and 16 to 64 parts per 

million, respectively. The concentration of 

dissolved solids was less than 300 parts per 

million for all samples, and the percentage 

of sodium was less than 46.

In order to define the chemical quality of 

the Loup River water more accurately, samples 

were collected at various discharges. Some 

concept of the relative discharges at sampling time may be realized in viewing the 

hydrographs of daily mean discharge for each 

station for the period January 1947 to September 1948. (See pis. 2-4.) The results of 

chemical analyses, in equivalents per million, 

are shown graphically above the daily mean 

discharge of the date on which the sample was 

collected. Instantaneous discharges for 

these samples are shown in tables 1 and 2. 

Samples collected in 1949 are included in 

this report but are not shown on the hydrographs .

Analytical results, in equivalents per million,' for samples collected during high and 

low discharges are shown in bar-graph form in 

figures 2-4. The principal acids and bases 

are represented by component sections of two 

columns; the height of each section is proportional to the quantity, as equivalents, of 

the ion it represents. The sum of the acids 

(acid column) is equal to the sum of the 

bases (base column); and the height of the 

double column, multiplied by two, is equal to 

the equivalent amount of all major ions in 

solution at the time of sampling.

Hardness values, in parts per million, of 

calcium carbonate (CaCOs) may be read to the 

right of the bar-graphs. A horizontal line 

drawn from the top of the magnesium section 

to the vertical line on the right will indicate the total hardness of that sample. Noncarbonate hardness (permanent hardness) is 

absent in samples shown by bar-graphs. Only 

three samples had permanent hardness, and the 

maximum value observed was 8 parts per million. (See tables 1 and 2.)

It is readily seen from the bar-graphs and 

tables 1 and 2 that the Loup River waters 

vary somewhat in mineral content. For the 

period of investigation, the South Loup River 

at St. Michael had the largest quantities of 

dissolved solids, which varied from 204 to 

298 parts per million during high and low 

flows. Downstream increases in mineral content are evident from results obtained at the 

two Middle Loup River stations (Dunning and 

St. Paul). The dilution effect of high discharge is illustrated in figures 2-4. For 

the most part, samples collected during periods of highest discharge had the smallest 

amount of dissolved solids and the least 

hardness.

An over-all comparison of the hydrologic 

information for each sampling station is 

given in table 3.

Geochemical Relationships and Salinity 

Characteristics

As rain falls to the surface of the earth, 

it picks up varying amounts of dissolved 

gases and impurities. Carbon dioxide (COg), 

present in the atmosphere, imparts to the 

rain water an acidic property that permits 

solution of various minerals, particularly 

limestone, as the water percolates to the 

water table. Any discharge of ground water 

thus stored should reflect to some extent 

the types of soils, minerals, and geologic 

beds through which the water percolated. The 

degree of solution of these various substances is dependent on such factors as time 

in contact, type of material, nature of infiltrating water, temperature, and base exchange .

The three branches of the Loup River generally carry siliceous, calcium bicarbonate 

waters. This would be expected of ground 

water that discharges from the dune-sand and 

lo«,ss areas that mantle the basin. The results of analyses of 19 samples from wells 31 

to 180 feet deep in the alluvium along the 

Middle Loup and South Loup Rivers indicate 

similarities to surface waters. Ranges in 

several mineral constituents and in other 

physical properties of the ground water are 

as follows:

Silica -------

Calcium ------

Magnesium - - - - -

Bicarbonate - - - -

Dissolved solids - - 

Hardness ------

Maximum Minimum

(parts per million)

58 35

114 32

15 4.8

396 127

516 186

371 100

See page 15 for list of references cited.

Generally, the ground water is more highly 

mineralized and harder than the surface
Table 1. Mineral constituents and related physical measurements for sampling stations on the main stem, L

Analytical results in parts per million except as indicated/

Date of 

collection

Discharge 

(secondfeet)

Specific

conductance

(micromhos/cm.

at 25° C.)

Silica Iron 

(Fe)

Calcium 

(Ca)

Magnesium 

(Mg)

Sodium 

(Na)

Potassium 

(K)

Bicarbonate 

(HC03 )

Sulfate

(so4)

Chloride 

(Cl)

Fluoride

(F)

Nitrate 

(N03 )

B

Middle Loup River at Dunning, Nebr.

Apr. 1, 1947 - -

May 6 - - - - -

Aug. 19

Sept. 21, 1949 -

418

1/364

394

3/344

7.1

8 T

7.1

7.3

199

10ft

193

178

60

f.n

61

56

0.08

.06

.04

23

22

20

25

4*4

4*4 

3.9

3.7

21

20

25

9.0

104

104

102

106

31

29

33

6.8

0

0

0

.6

0.4

.3

.3

2.2

1.4

2.2

1.5

Middle Loup River at St. Paul, Nebr.

Dee. 1, 1943 - -

Mar. 26, 1947 -

MftTT ft ......

Sept. 2

June 8, 1948 - -

June 22

July 20

July 29 ----

Aug. 13

Mar. 5, 1949 - -

Mar. 6 - - - - -

June 7 - - - - -

1,150

1

A&A jUDU

623

941

3,880

2,020

2,990

5,070

jj/8,000

3 

ran t \IJftJ

7,250

7,940

8.0

7.7

8

4

O

8.1

8.3

8.3

7.5

7.1

7.5

7.5

7

r

.? 

70

 «

7.2

244

284

nAf.

fao

288

272

191

235

157

174

198

toft Ays

2L2 "" I"1

242

58

61

62

62

34

33

31

28

32

?* 32

35

29

.05

.02

.02

.08

.07

.08

.02

.02

.12

.10

.10

.10

35

ni

3t>

34

38

23

34

22

22

29

31

32

35

5.9

6.6

5.9

4.9

2.0

4.4

2.9

2.0

4.2

5

4

 3

4*7

4.2

6.2

17

19

26

12

16

9.2

8.2

12

5.5

4.6

14

12

148

151

2/156

150

2/162

3/103

138

92

101

112

120

* I A

148

140

7.0

22

27

40

3.2

8.8

5.6

6.4

3.2

4.8

i r> ? «

6.4

12

2.2

0

0

0

1.0

1.0

1.0

1.0

1.0

2.0

1.5

.5

1.0

 4

.4

.3

.2

.2

.3

.1

.1

.3

.3

.3

2.0

2.2

1.1

1.4

3.2

5.4

2.3

1.3

1.4

1.3

o

 «c

.3

Loup River near Columbus, Nebr*

Bov. 8, 1945 -- I 208 1 7*9 1 240 | 50 I .05|33 I 6.5 |7.6 \ 6.2 1 144 1 H I 1.8 | .2 | 1.1 | 

1 Mean daily discharge.

2 Includes 4*9 parts per million carbonate (003).

3 Includes 14 parts per million carbonate (C0-j). 

^ Includes 2.0 parts per tin* carbonate (083). 

5 Discharge approximate ice conditions.
Table 2. Mineral constituents and related physical measurements for sampling stations ontributaries to 

^Lnalytical results in parts per nil],ion except as indicated/

Date of 

collection

Discharge 

(secondfeet)

pH

Specific

conductance

(aicroahos/em.

at 2JJO C.)

Silica 

(SiX>2)

Iron 

(Pe)

Calcium 

(Ca)

Magnesium 

(Mg)

Sodium 

(Ha)

Potassium 

00

Bicarbonate 

(HC03)

Sulfate 

(S04)

Chloride 

(01)

Pluoride

(F)

Nitrate 

0*3)

B

South Loup River at St. Michael, Nebr.

Apr. 2, 1947 - -

May 1 - -- -- 

Aug. 20 - - - -

June 22/1948 -

July ]£----

July 29

Sept. 22, 1949 -

Dec. 1, 1943 - -

Mar. 26, 1947 -

Vo-ir ft _____

Aug. 25

July 29, 1948 -

Mar. 5, 1949 - -

Mar. 6 - - - - -

Apr. 2, 1947 - -

May 6

Aug. 27

Feb. 26, 1949 -

Apr. 2, 1947 - -

Aug. 27

June 22, 1948 -

July 29 --- -

****o* "*

Mar. 3, 1949 - -

Mar. 7 _-.._

May 23 ----- 

Sept. 27 - - - -

3/244

o/i» 2OB

124

1,190

2,000

1,900

1A6S

_

934

762

329

1,950

4/3,690

2^900

7.3

* i 8*4

8.2

8.5

7.1

7.2

7.5

454

466 *pjs»

452

285

264

258

394

8.0

8.2

7.4

7.0

7.5

7.4

7.4

211

237

232

239

255

226

195

56

59

56

38

34

36

46

0.05

AC O?

.05

.04

.18

.30

.02

_

64

49

50

40

35

33

__

.08

.11

.13

.40

.07

.10

60

in

OH

62

40

39

32

59

9.8

10

9.6

6.0

6.0

5.5

8.9

22

O I 24 

23

8.8

9.0

16

17

246

2/256

244

2A58

158

152

238

29

33

38

4*0

8.0

11

17

2.0

2

f\

 U 

2.0

1.3

1.0

0

3.4

0.2

.2

.8

.4

.3

.2

North Loup River near St. Paul, Nebr.

_

26

31

29

43

28

26

__

5.9

6.3

6.8

5.5

4.6

4.6

10

15

7.1

11

5.1

5.3

6.2

326

120

131

135

149

109

107

5.0

19

9.5

12

16

4.0

5.6

2.0

0

0

0

1.0

3.5

1.5

_

.4

.4

.3

.3

.3

.3

3.1

2 

"I

 JL 

2.8

7.1

1.6

.8

3.8

0

2.5

2.8

.5

.9

0

1.0

1.1

Cedar River near Spalding, Nebr.

47

123

42

61

72

44

30

311

419

55

95

619

311

39

7.0

7

« 

 Z

8.2

7.6

203

228

204

195

37

40

47

42

.12

*M\

 20

.13

.12

7.3

7.9

8.0

8.5

7.0

7.6

7.2

7.0

d

t\

 w

7.7

246

248

229

175

157

233

224

3S3

225

274

36

36

40

19

16

42

35

16

27

38

.20

.20

.12

.40

.50

.16

.11

.02

.03

.08

26

30

26

27

6.3

7

1 4 

6.8

6.8

5.7

5.6

5.4

3.9

116

133

117

117

6.6

7

f\

.0 

7.4

5.6

Beaver Creek near Loretto, Nebr*

33

35

31

26

20

35

31

26

35

31

6.8

7.0

7.2

3.8

3.0

4.4

5.2

2.7

4.2

5.4

7.2

5.7

5.1

7.4

9.3

8.8

8.5

8.7

Q rO 

7.6

144

148

135

5/102

89

145

132

102

127

136

5.8

5.8

5.8

10

6.4

4.0

5.6

4.0

15

1.6

0

0

0

.5

.2

.2

.2

.9

.7

1.1

0

0

0

0

1.5

0

1.0

2.0

.5

1.4

.3

.2

.3

.5

 3

.4

.3

.1

9

 «

.2

1.4

.8

.8

1.2

0

.7

1.5

5.2

3

rt

 0

.8

1 Mean daily discharge.

2 Includes 9*8 parts per million carbonate (003).

3 Includes 11 parts per »nn<wi carbonate (003).

^ Discharge approziDate ice conditions.

5 Includes 12 parts per million carbonate (COj).
GEOLOGICAL SURVEY CIRCULAR ior

April I 

157 ppm 

4(8 cfi

i 2 5 i i i to i i i > 20 <N i > 20 j 5 i ) 20 3 i ) eo so i > 2o 3 i i to 31 io 20 30 io zo si io 20 so fo 20 si io 20 si io 2o M io «o si io 2o so is 15 S i so io So S io IS S

A. HYDROGRAPH OF MIDDLE LOUP RIVER AT DUNNING. JANUARY 1947 - SEPTEMBER 1948

July 20 July 29 Au(uitl3

162 ppm 129 ppm 142 ppm

2,020 cfi 2.990 cfi 5J3TO cf

B HYDROGRAPH OF MIDDLE LOUP RIVER AT ST. PAUL, JANUARY 1947 - SEPTEMBER 1948
GEOLOGICAL SURVEY

CIRCULAR 107

> JjOOO

2 i.o

K> 2O SO K> 2O IO tO 31 10 tO 90 10 tO 31

 IUNC JULY

'O «> »' 10 20 SO 

AU6UST SCPTCMKR

A HYOROGRAPH OF SOUTH LOUP RIVER AT ST. MICHAEL, JANUARY 1947 - SEPTEMBER 1948

(Sodium + 

J Polonium

I Mognctium 

I Cotcium

I Chioritt 

I Nltrot*

| Bicarbonate 4- 

I Carbonate

 ZIJ5 )0 rMarch 26 

174 ppm 

934 cfs

May 6 

175 ppm 

762 eft

August 25 

162 ppm 

329 eft

July 29 

208 ppm 

1,950 eft

V

B HYOROGRAPH OF NORTH LOUP RIVER NEAR ST. PAUL, JANUARY 1947 - SEPTEMBER 1948
GEOLOGICAL SURVEY CIRCULAR 107 PLATE 4

I

7

20 31 10 20 26 10 2O 31 IO 2O 3O IO I 

JANUARY FCtRUARV MARCH APRIL NAY

IO 2O SO IO IO 31 K> IO -31 IO IO SO IO 2O 31 IO 2O SO IO IO 

JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DECEMBER

10 20 

JANUARY

IO IO 21 IO 20 31 IO 2O 3O IO 2O 31 IO 2O SO IO tO 31 10 10 

FEBRUARY NARCH APRIL NAY JUNE JULY AU8UST

A. HYOROGRAPH OF CEDAR RIVER NEAR SPALOIN6, JANUARY 1947 - SEPTEMBER I94B

>O 2O 31

B HYDROGRAPH OF BEAVER CREEK AT LORETTO, JANUARY 1947-SEPTEMBER 1948
c 

o

«

0.

er 

UJ

A. Middle Loup River at Dunning May 6,1947 

B. Middle Loup River at St. Paul Aug. 13,1948

C. Middle Loup River at St. Paul 

D.Loup River at Columbus Nov. 8

Sodium + 

Potassium

Magnesium 

Calcium

Chloride + 

Nitrate

ISulfate

I Bicarbonate+ 

(Carbonate

Discharge i second-feet 364 (average) 5,070 I high) 623 (low) 

Figure 2.--Mineral constituents during high,average, and low flow main 
o 

a.

cr

UJ

A. South Loup River at S t. M ich aeI July 18.1948 

B, South Loup River at St. Michael Aug. 20,1947

C.North Loup River at St. P

D.North Loup River at St. P

I [Sodium 4- 

I_I Potassium

Mschorge (second-feet) 2,OOO 124 2,9OO 

Figure 3.--Mineral constituents during high and low flow major tribut
E

w 3

Q.

'5 2 

cr

LL)

A. Cedar River near Spalding May 6, 1947 

B. Cedar River near Spalding Aug. 27, 1947

C. Beaver Creek near Lo

0.Beaver Creek near Lo

Sodium + 

Potassium

Magnesium 

Calcium

Chloride + 

Nitrate

Sulfate

Bicarbonate + 

Carbonate

Discharge (second-feet) 123 42 419 

Figure 4.--Mineral constituents during high and low flow minor trib
Table 3. Comparative hydrologlc Information for the Loup River and Its tributaries

Sampling station

Middle Loup River at Dunning - - - 

Middle Loup River at St. Paul - - -

South Loup River at St. Michael - - 

North Loup River near St. Paul - -

Drainage 

area 

( square 

miles)

1,760

7,720 

15,230 

2,560

4,460 

794 

311

Annual mean 

daily discharge

Water year

1947^

392

1,433 

1,322 

182

979 

170 

74.2

1948

368

1,232 

1,139 

300

908 

125 

62.5

Predominant chemical 

characteristics

Highly siliceous; moderately 

hard; practically chloride - 

free. 

Siliceous; hard. 

Siliceous; hard. 

Moderately siliceous; very 

hard. 

Siliceous; moderately hard. 

Siliceous; moderately hard. 

Moderately siliceous; moderately hard.

water. Dissolved solids in ground waters 

ranged from 186 to 516 parts per million and 

averaged. 312 parts per million. Hardness 

ranged from 100 to 371 parts per million and 

averaged 197 parts per million. A noticeable 

downward trend in the percentage of silica in 

ground water sampled between Dunning and St. 

Paul was also observed in the surface water. 

The average silica was 16.4 percent of the 

anhydrous residue.

Although more mineralized, the ground water

is similar in composition to the surface

water. This relationship is seen in table 4.

According to Lugn (1935) most of the dune 

sand of the sand-hills region of northcentral Nebraska is underlain by the Arikaree, 

Harrlson, and Sheep Creek formations of 

Miocene age, all of which are more siliceous 

than calcareous.

Palmer (1911) states in his description of 

the properties of natural waters,

Nearly all terrestrial waters have two 

general properties, salinity,and alkalinity, on whose relative proportions 

their fundamental characters depend. Salinity is caused by salts that are not 

hydrolyzed; alkalinity is attributed to 

free alkaline bases produced by the hydrolytic action of water on solutions of 

bicarbonates and on solutions of salts 

of other weak acids.

In the study of surface water quality of 

the streams in the Loup Basin, the use of 

Palmer's formula is helpful in classifying 

the water by expressing chemical proportions, 

of the ions in solution as well as variations 

in the proportions themselves. The factor of 

concentration is eliminated in this method of 

expression, and the properties of the solution are expressed in percentage proportion. 

The percentage of reacting value is computed 

from equivalents per million and plotted on a 

trilinear diagram, as proposed by Hill (1942), 

to show the character of each water.

The trilinear diagram (see fig. 5) used in 

this report is a modification of Hill's diagram with the diamond expressing salinity and 

alkaliriity set apart from the positive-ion 

and negative-ion triangles. Primary salinity 

may be described as sodium and potassium 

(alkali) salinity, secondary salinity as calcium and magnesium (permanent hardness) salinity, primary alkalinity as sodium and potassium (permanent) alkalinity, and secondary

alkalinity aa calcium and magnesium (temporary) alkalinity. Water is classified according to the proportions of the above properties. *

It is noted from a study of figure 5 that 

all the Loup River waters are essentially 

secondary alkaline in character, and that 

each stream exhibits individual deviations. 

The character of the Middle Loup River water 

is noticeably changed below the confluence 

with the South Loup River above St. Paul. 

Prom this point on downstream to Columbus, 

the character of the water in the main stem' 

is influenced by salt contributions from the 

North Loup River and tributaries.

Secondary salinity (permanent hardness) is 

noticeably absent in all the waters, as may 

be seen in the following comparative table, 

which shows the salinity and alkalinity characteristics of the Loup River and its tributaries :

Salinity and alkalinity percentages, Loup 

River and its tributaries

Sampling station A B C_

Middle Loup River at Dunning - 65 25 10

Middle Loup River at St. Paul - 78 12 10

Loup River at Columbus - - - - 82 12 6

South Loup River at St. Michael 81 11 8

North Loup River near St. Paul 85 12 3

Cedar River near Spalding - - - 73 7 20

Beaver Creek at Loretto - - - - 85 8 7

A--Secondary alkalinity. 

B Primary salinity. 

C--PrJmary alkalinity.

The percentages expressed in figure 5 are 

calculated from the data in tables 1 and 2 

and are the median of all analyses for each 

station studied. The following characteristics and trends are observed: (1) an increase of 13 percent in secondary alkalinity 

and a corresponding decrease of 13 percent in 

primary salinity between Dunning and St. Paul 

on the Middle Loup River; (2) the Cedar River 

near Spalding contributes water of 13 percent 

more primary alkalinity than Beaver Creek at 

Loretto; (3) the North Loup River near St. 

Paul has less primary alkalinity than any of 

the streams studied; and (4) the Middle Loup 

River at Dunning has a greater proportion of 

primary salinity than any of the streams 

studied.
10

Table 4.--Percentages of reacting values of ions for waters in the Loup River basin

Date

Cation (t) percentages

Calcium 

(Ca)

Magnesium 

(Mg)

Sodium and 

potassium 

(Na t K)

An ion ( - ) percentages

Bicarbonate 

(HC03 )

Sulfate 

(S04 )

Chloride, fluoride, 

and nitrate 

(Cl t P t NOs)

SURFACE WATER

Middle Loup River

Apr. 1, 1947 - 

May 6 - - - - 

Aug. 19 - - - 

Sept. 21, 1949

47.7 

46.8 

41.5 

64.4

14.9 

15.3 

13.3 

15.5

37,4 

37.9 

45.2 

20.1

 - Dunning

71.3 

73.4 

69.6 

89.7

27.1 

25.8 

28.8 

7.2

1.6 

.8 

1.6 

3.1

Middle Loup River - St. Paul

Mar. 26, 1947

May 8 - - - -

Sept. 2 - - -

June 8, 1948 -

June 22 - - -

July 20 - - -

July 29 - - -

Aug. 13 - - -

Mar. '5, 1949 -

Mar. 6 - - - -

June 7 - - - -

June 9 - - - -

58.4

57.0

50.9

 67.4

57.5

69.1

64.7

61.8

71.1

70.8

61.8

67.3

16.3

17.1

14.7

14.2

8.0

14.6

14.1

9.0

17.2

20.1

15.1

13.5

25.3

25.9

34.4

18.4

34.5

16.3

21.2

29.2

11.7

9.1

23.1

19.2

83.2

81.5

74.3

94.7

84.9

92.2

89.3

93.3

91.1

90.8

93.8

88.1

15.4

17.8

25.1

2.5

9.0

4.9

7.7

3.9

5.0

6.9

5.0

9.6

1.4

.7

.6

2.8

6.1

2.9

3.0

2.8

3.9

2.3

1.2

2.3

South Loup River - St. Michael

Apr. 2, 1947 -

May 1 - - - -

Aug. 20 - - -

June 22, 1948

July 18 - - -

July 29 - - -

Sept. 22, 1949

62.9

62.0

63.1

69.7

68.9

58.2

66.5

17.1

17.3

16.1

17.1

17.3

16.3

16.5

20.0

20.7

20.8

13.2

13.8

25.5

17.0

85.0

84.3

81.6

91.9

91.8

91.2

88.2

12.7

13.9

16.1

2.8

6.0

8.4

7.9

2.3

1.8

2.3

5.3

2.2

.4

3.9

North Loup River - St. Paul

Mar. 26, 1947

May 8 - - - -

Aug. 25 - - -

July 29, 1948

Mar. 5, 1949 -

Mar. 6 - - - -

53.3

65.1

58.0

76.2

69.7

66.7

.20.1

21.9

22.4

16.0

18.9

19.5

26.6

13.0

19.6

7.8

11.4

13.8

81.4

91.1

89.5

87.1

89.9

90.7

16.5

8.5

10.1

11.8

4.0

6.2

2.1

.4

.4

1.1

6.1

3.1

Cedar River - Spalding

Apr. 2, 1947 -

May 6 - - - -

Aug. 27 - - -

Feb. 28, 1949

62.8

63.6

61.9

64.9

25.1

25.8

26.7

26.9

12.1

10.6

11.4

8.2

92.7

93.2

92.3

92.8

6.8

6.4

7.2

5.8

.5

.4

.5

1.4

Beaver Creek - Loretto

Apr. 2, 1947 -

May 5 - - - -

Aug. 27 - - -

June 22, 1948

June 29 - - -

Aug. 1 - - - -

Mar. 3, 1949 -

Mar. 7 - - - -

May 23 - - - -

Sept. 27 - - -

65.5

68.0

65.7

67.4

60.2

70.3

66.0

68.4

70.8

66.8

22.2

22.4

25.0

16.0

15.1

14.5

18.3

11.6

14.2

19.0

12.3

9.6

9.3

16.6

24.7

15.2

15.7

20.0

15.0

14.2

94.4

94.9

94.4

88.0

89.6

96.4

92.7

87.9

84.2

96.1

4.8

4.7

5.1

11.0

8.0

3.2

5.2

4.2

12.6

1.3

.8

.4

.5

1.0

2.4

.4

2.1

7.9

3.2

2.6

Loup River - Columbus

Nov. 8, 1945 - |

1

61.8 |

66.6 j

19.9

17.3

| 18.3 | 88.4

GROUND WATER 

Average (19 samples)

| 16.1 | 84.9

1 8.6 |

1 6.7 |

3.0

8.4
20 60

Note! All vertexes equal 100 percent.

x Middle Loup River at Dunning

a Middle Loup River at St. Paul

 Loup River at Columbus

 South Loup River at SI. Michael

 North Loup River at St. Paul

	BO

0 Cedar River at Spotding

3> Beaver Creek at Loretto

40

A| 

A2 

Sj 

S2 

60

Mg

20

20 40 60 60 Na+K HGO» 80 60 4

o

Figure 5.~~Geochemical classification of Loup River waters (
12

The reacting value of calcium in the Middle 

Loup River at St. Paul (see table 4) increased from approximately 51 to 71 percent 

between September 2, 1947, and March 5, 1949, 

and there was a corresponding decrease for 

sodium and potassium {considered together) 

from 34 to 12 percent. For this same period 

the percentage of reacting value of bicarbonate increased from 74 to 91; whereas the 

percentage of sulfate decreased from 25 to 5. 

(See fig. 6.) A similar, but less pronounced, 

trend occurred in water of the North Loup 

River at St. Paul.

Considerable variation is also found in the 

silica content of the Loup River streams. 

This variation is evident if the silica is 

expressed as a percentage of anhydrous residue. During the period studied, the Middle 

Loup River at Dunning had the highest and the 

South Loup at St. Michael the lowest average 

percentage of silica. The average percentages of silica in decreasing order for each 

sampling station are shown in the following 

table and are illustrated in figure 7.

Silica

Sampling

station

Middle Loup River at Dunning - - 

Cedar River at Spalding - - - - 

North Loup River near St. Paul - 

Loup River at Columbus - - - - - 

Middle Loup River at St. Paul - 

Beaver Creek at Loretto - - - - 

South Loup River at St. Michael

Percent of

anhydrous

residue

38.1

26.6

26.1

25.5

23.3

19.2

18.2

The Middle Loup River at St. Paul shows the 

following decreasing trend in percentage of 

silica for the period of sampling:

Date

Mar. 26, 1947 - - - 

May8-------

Sept. 2 ----- -

June 8, 1948 - - -

June 22 ----- -

July 20 ----- -

July 29 - - - 

Aug. 13 - - 

Mar. 5, 1949

Mar. 6 

June 7 

June 9

Percent SiOg

29.4

29.5

31.8

27.0

20.6

18.1

24.0

19.7

20.3

19.8

20.9

17.7

Quality of Water in Relation to Use

The waters of the Loup River and Its tributaries (see fig. 1) are satisfactory for 

irrigation in areas of average soil and 

drainage conditions. For streams studied, 

the waters would be termed "good" or 

"excellent" by Wllcox 1 s classification of 

irrigation waters (1948). (See table 5.)

The specific characteristics during high 

and low discharges at the six sampling points 

are shown in table 6.

Table 5. Permissible limits for electrical conductance, percent sodium, and boron in several

classes of irrigation water

Classes of water

Rating

1 

2 

3 

4 

5

Grade

Excellent 

Good 

Permissible 

Doubtful 

Unsuitable

Electrical 

conductivity 

(micromhos/cm. at 25° C.)

< 250 

250 - 750 

750 - 2,000 

2,000 - 3,000 

> 3,000

Percent sodium

< 20

20 - 40 

40-60 

60 - 80 

> 80

Boron I/ 

(p. p.m.)

<C 0.33 

0.33 - 0.67 

0.67 - 1.00 

1.00 - 1.25 

> 1.25

I/ For crops sensitive to boron.

Table 6. Classification for irrigation use of Loup River streams during high and low discharges

Sampling point

Middle Loup River at Dunning - -

Middle Loup River at St. Paul - -

South Loup River at St. Michael -

North Loup River near St. Paul

Cedar River near Spalding - - - -

Beaver Creek at Loretto - - - - -

Discharge 

(sec. -ft. )

418

344

8,000

623

2,000

124

3,690

329

123

42

619

30

Electrical 

conductivity 

(micromhos/cm. 

at 25° C.)

199

178

198

288

264

452

226

239

228

204

TO. * JLVO

229

Percent 

sodium

37

20

12

35

14

21

11

20

10

11

Of) &w 

9

Boron 

(p. p.m.)

0.02

.07

.02

.06

.19

.06

.01

.14

.00

.12

Class

Good.

Good.

Excellent.

Good.

Good.

Good.

Excellent.

Good.

Excellent.

Excellent.

Good.

Excellent.
Q» 

C

100

90

80

ro

60

90

o 40

20

10

*"" o

I I I 1 I

_-- -- HC03

Ca

I I I I

1947 1940 1949

Sampling period

Figure 6. Percentage of reacting value of several major ions, 

Middle Loup River at St. Paul.
14

3Z

28

H 24 

Z

UJ 

0

u 20 

a.

z"" 16

M 

O

£ I2

< 

0

_J 

0) 8

4 

O

1

<

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<D' 

,CM>

1' ('

1

1

!

CD

'>i 

.O'

y ,

,04, '£

*

-8: 

T

MIDDLE LOUP RIVER AT

/ '

/8'

/^

^

.

,w

,Csl 

'«>'

/&,">'

!

M

^'3,

'-5 

/ y

1

,ov

,<H

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>7

ST. PAUL, NEBR.

1

G'

'*-/

;s: ''O*

/*'

t

n^Ti

|

f

2tf>'

'x:'

'Oy

'*

'^ ,, 1

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1

Figure 7.--Trends in content of silica in waters, Loup River basin.
15

SUMMARY

The chemical characteristics of surface 

waters in the Loup River basin indicate a 

substantial ground-water inflow from known 

subterranean formations* These waters are 

moderately mineralized and hard. The concentration of dissolved solids* composed largely 

of calcium bicarbonate and silica, ranged 

from 120 to 298 parts per million; hardness, 

as calcium carbonate, ranged from 62 to 198 

parts per million.

Waters in the Middle Loup River at Dunning 

and the Cedar River at Spalding carry higher

percentages (by weight) of silica than are 

found in other surface waters in the basin. 

Similarly, the waters at these two stations 

have higher percentages of primary alkalinity. 

This correlation supports evidence of other 

investigators that the primary alkalinity and 

the silica content in a water are related.

Concentrations of boron and percentages of 

sodium in the waters were low, and water impounded from any or all of these streams for 

irrigation should be suitable for crops under 

most conditions.

LIST OF REFERENCES

Am. Public Health Assoc., 1946, Standard methods for the examination of water and sewage: 9th ed. 

286 pp.

Collins, W. D., 1928, Notes on practical water analysis: U. 3. Qeol. Survey Water-Supply Paper 

596-H, pp. 236-261.

Foote, F. J., 1932, Determination of boron in water: Ind. and Bng. Chemistry, Anal, ed., vol. 4, 

pp. 39-42.

Hill, R. A., 1942, Salts In irrigation water: Am. Soc. Civil Eng. Trans., vol. 68, no. 107, pt. 

2, pp. 1478-1493.

Lugn, A. L., 1935, The Pleistocene geology of Nebraska: Nebraska Qeol. Survey Bull. 10, 2d ser., 

p. 164.

Palmer, Chase, 1911, The geochemical interpretation of water analyses: U. S. Qeol. Survey Bull. 

479, p. 11.

Wilcox, L. V., 1932, Electrometric titration of boric acid: Ind. and Bng. Chemistry, Anal, ed., 

vol. 4, pp. 38-39.

Wilcox, L. V., 1948, The quality of water for irrigation use: U. S. Dept. Agr. Tech. Bull. 962, 

p. 27.