UNITED STATES DEPARTMENT OF THE INTERIOR 

Harold L. Ickes, Secretary

GEOLOGICAL SURVEY 

W. C. Mendenhall, Director

Water-Supply Paper 796

CONTRIBUTIONS TO THE HYDROLOGY

OF THE UNITED STATES

1937

NATHAN C. GROVER, Chief Hycfcgulic Engineer

t UNITED STATES ' " tB

O ~W ._,

» GOVERNMENT PRINTING OFFICE CD a

, fS2 ° WASHINGTON: 1939 *9 Y^ t*

1^ -

CONTENTS

[The letters in parentheses preceding the titles are those used to designate the papers for separate

publication]

Page

(A) Methods of locating salt-water leaks in water wells, by Penn Livingston and Walter Lynch (published in July 1937)________ __ 1

(B) Flood on Republican and Kansas Rivers May and June 1935, by

Robert Follansbee and J. B. Spiegel (published in June 1937)_____ 21

(C) Flood in La Cafiada Valley, California, January 1, 1934, by H. C.

Troxell and J. Q. Peterson (published in December 1937). ____ 53

(D) Geology and ground-water resources of Ogden Valley, Utah, by R. M.

Leggette and G. H. Taylor (published in September 1937) ___ __ 99

(E) Ground water in Avra-Altar Valley, Arizona, by D. A. Andrews (published in August 1937)___________________________ 163

(F) Geology and ground-water resources of the valley of Gila River and 

San Simon Creek, Graham County, Arizona, by M. M. Knechtel, 

with a section on the chemical character of the ground water by 

E. W. Lohr (published in June 1938) __ _______________ 181 

(G) Major Texas floods of 1935, by Tate Dalrymple and others 223

Index. 285

ILLUSTRATIONS

Page

PLATE 1. A, Section of a pump column showing the effect of corrosion by 

salt water; Bt Well casing showing holes made by salt water.

2. A, Deep-well current meter; B, Power-driven winch used for 

lowering and raising equipment in wells_________________

3. A, Deep-well water sampler with electrodes used in Winter 

Garden area, Tex.; B, Deep-well water samplers used in 

Sarasota County, Fla________________________________

4. A, Cross section of deep-well water sampler used in Winter 

Garden area, Tex.; B, Cross section of deep-well water 

sampler used in Kleberg Coutry, Tex.; C, Cross section of 

deep-well water sampler used in Sarasota County, Fla______

5. A, Wheatstone bridge used in Winter Garden area, Tex.; B, 

Apparatus used to explore wells in Sarasota County, Fla 

6. A, Diagram of Wheatstone bridge direct-current electric circuit 

used in Winter Garden area, Tex.; B, Diagram of milliameter 

direct-current electric circuit used in Kleberg County, Tex.; 

C, Diagram of Wheatstone bridge alternating-current electric circuit used in Sarasota County, Fla_ _____

m

14

14
IV ILLUSTRATIONS

Page

PLATE 7. A, Equipment with miniature electrodes used in Winter Garden 

area, Tex.; B, Hand-operated apparatus used to explore wells 

in Kleberg County, Tex__________________-____-________ 14

8. A, Cross section of miniature electrodes used in Winter Garden 

area, Tex.; B, Cross section of miniature electrodes used in 

Kleberg County, Tex., and in Sarasota County, Fla________ 14

9. Diagrams showing locations of salt-water leaks in water wells 

in Kleberg County, Tex., indicated by the miniature electrodes-milliameter equipment___-_-----------______--_-_ 14

10. Isohyetal map of Republican River-Kansas River Basin and 

adjacent regions showing total rainfall in inches observed 

for May 27 to June 2, 1935______________-____ 28

11. A, Kansas River at Topeka, Kans., June 5, 1935; B, Solomon 

River at Beloit, Kans., June 3, 1935; C, Republican River 

 west of Culbertson, Nebr., June 11, 1935_______________ 36

12. A, Republican River at Cambridge, Nebr., June 1, 1935; B,

Republican River at Red Cloud, Nebr., June 2, 1935____ 36

13. Hydrographs of flood stages on Republican and Kansas Rivers,

June 1-11, 1935_________-______---__-_ ----__-____ 36

14. A, Republican River at Scandia, Kans., June 2,1935; B, Republican River at Wakefield, Kans., June 3, 1935._________ 36

15. Location of gaging stations in Republican River-Kansas River

drainage basin________-_-_____________-___-----______ 44

16. La Canada Valley, looking north._________________________ 56

17. Western part of drainage area of Pickens Creek________ 56

18. Map of Los Angeles and vicinity____________________ 56

19. A, Typical scene of destruction; B, Encroachments on channel

of Pickens Creek________________.___________ 72

20. A, Condition of check dam and channel in canyon section of 

Pickens Creek; B, Area on Pickens Creek sparsely covered 

by chaparral________________________________________ 72

21. A, Condition of channel of Pickens Creek above altitude of 

about 3,200 feet; B, Material from adjacent slopes slumped 

into the bed of Pickens Creek___-____-__-__---_-_--_--_- 72

22. A, Pickens Creek at altitude of about 2,300 feet; B, Channel of

Pickens Creek on debris cone at altitude of about 2,000 feet- 73

23. A, B, Stream-bed erosion on debris cone in Pickens Creek ____ 80

24. A, Debris deposited in Pickens Creek during storm of October 

1934; B, Canyon section of Pickens Creek immediately below 

a sharp bend___________________________---_-___-__-__- 80

25. A, Abrasion marks on tree trunk in Pickens Canyon; B, Damaged condition of trees caused by swiftly moving debris and 

water in canyon section of Pickens Creek__-_______-____-- 80

26. A, Small falls in Pickens Canyon; B, Debris in channel of Fish

Creek, April 2, 1925-__-_-__-________._._ ___ . 81

27. A, Debris in channel of Fish Creek, April 18, 1925; B, Channel

of Dunsmore Creek at end of New York Avenue_________ 88

28. A, Two boulders on pavement at end of New York Avenue;

B, East bank of Pickens Creek at Orange Avenue______-_-_ 88

29. A, West bank of Pickens Creek at Orange Avenue; B, Pickens

Creek about a quarter of a mile above Orange Avenue.___ 88

30. A, Composition of debris deposits in channel of Pickens Creek;

B, Debris basin in Haines Canyon.______________________ 89
ILLUSTRATIONS V

Page 

PLATE 31. A, Example of soil erosion; B, Example of gully erosion______ 96

32. Typical landslides: A, Slide in upper end of the debris cone on 

Pickens Creek; B, Landslide in Brand Park, Glendale Highlands___-_____________________________ 96

33. A, Check dam in Haines Canyon; B, Debris above a check dam

in Pickens Canyon_________________-___________________ 96

34. A, Debris above a check dam in Haines Canyon; B, Landslides 

on forest-covered slopes of Verdugo Mountains near Glendale-_-_--_----_-_-_-__--___-___--_-_--_-_-__-___--__- 97

35. Annual cumulative departure from normal precipitation at 

Ogden, Utah, and annual precipitation at Ogden and Huntsville, Utah_______________________________________ In pocket

36. Map of part of Ogden Valley, Weber County, Utah__ __ In pocket

37. Graphs of flow of South Fork of Ogden River, precipitation at 

Ogden, withdrawal of ground water at Artesian Park, and 

water levels in five observation wells in Ogden Valley, 

1932-35_____-_________________---__--_-____________In pocket

38. Hydrographs of observation wells in Ogden Valley and flow of

South Fork of Ogden River_______________________ In pocket

39. Stream flow in Ogden VaUey, 1933-34____________ In pocket

40. Well logs, Ogden Valley, Utah__________________________In pocket

41. Map of Avra-Altar Valley, Arizona, showing wells and groundwater conditions______________________________________ 164

42. A, Cerro Colorado, on east side of Altar Valley; B, Baboquivari

Mountains, on west side of Altar Valley._________________ 168

43. A, Lowland near Brawly Wash and bluffs rising to terrace land, 

looking east to Sierrita Mountains; B, Sparse vegetation in 

Altar Valley west of Sierrita Mountains __________________ 168

44. A, Sahuaro cactus on upper slope of Avra Valley, west of Tucson 

Mountains; B, Vegetation on upper slope of Altar Valley, looking southeast to Sierrita Mountains_______-_________-_-_- 169

45. Topographic map of Graham County and vicinity, Arizona. __ 184

46. Map showing geology, wells, and springs in parts of the valley 

of the Gila River and San Simon Creek, Graham County, 

Ariz______________________________________________ In pocket

47. A, View looking north over irrigated lowlands along the Gila 

River near Solomonsville; B, View looking northwest down 

San Simon Valley from a point near Tanque______________ 192

48. A, View looking north along San Simon Creek near Solomonsville; B, San Simon Creek near Tanque________________-_- 192

49. A, Remnants of upper terrace on flank of Graham Mountains; 

B, View looking south toward Graham Mountains from point 

near Thatcher_______________________________ 192

50. A, Lake beds exposed at Red Knolls "desert theater," in valley 

\Yz miles southwest of Ashurst; B, Gila conglomerate on Big 

Spring Wash, near center of T. 5 S., R. 25 E_________ 192

51. A, Badlands developed in fossiliferous lake beds about 2 miles 

west of Bear Springs, T. 7 S., R. 23 E.; B, Fossiliferous lake 

beds near 111 ranch, in sec. 27, T. 8 S., R. 28 E______ 200

52. A, Diatomite with thin chert layers in lake beds 1 mile east of 

111 ranch; B, Cienaga Springs, in Jacobson Wash, east of 

Cactus Flat_____________________________ 200

53. A, Flow of warm water from Final Oil Co.'s Whitlock No. 1

well, in sec. 36, T. 10 S., R. 28 E.; B, Indian Hot Springs_ 216
VI ILLUSTRATIONS

Page 

PLATE 54. Map of Texas showing principal towns and streams mentioned

in the text._____________________________ 224

55. Map of Texas showing major topographic divisions and major

drainage basins._______________________________________ 224

56. Llano River at Llano at about peak of flood of June 14, 1935. _ 240

57. Bridges destroyed by flood of June 14, 1935: A, Llano River 

on Mason-Fredericksburg highway; B, Nueces River on 

Uvalde-La Pryor highway_____-------------------__-_ 240

58. Isohyetal map of the major part of the Colorado and Nueces

River Basins and parts of adjacent river basins__-__-______ 240

59. Congress Avenue Bridge, Colorado River, at Austin: A, At

about peak of flood of June 15, 1935; B, At low water______ 240

60. A, Colorado River at Austin, looking north on Congress Avenue 

from right bank at about peak of flood of June 15, 1935; 

B, South Llano River at Junction, near peak of flood of June 

14, 1935-_-__-_._-_ _____________________________ 248

61. Nueces River on Uvalde-La Pryor highway: A, View from left 

bank at about 10 feet below peak stage on June 14, 1935; 

B, View from right bank made about 30 minutes before 

bridges were destroyed.---------------------.---------- 248

62. West Nueces River near Brackettville: A, Looking upstream 

from just below lower cross section; B, Looking toward right 

bank and upstream from about lower cross section.__ ___ 249 

FIGURE 1. Diagram showing fluctuations in chloride content of water 

pumped from the Pickna well in the Winter Garden area, 

Tex________..___.___________________ 5

2. Diagram showing fluctuations in chloride content of water 

pumped from the Pollard well after the well had been 

repaired.____________________________________________ 7

3. A, chloride content (parts per million) of samples brought up 

by the deep-well sampler from the E. C. Smith well near 

Catarina, Tex.; B, Resistance of the water at different dpeths 

in the E. C. Smith well as indicated by the Wheatstone bridge. 11

4. Diagrams showing the effect of varying the voltage on the

resistance and conductivity of saline waters._____________ 15

5. Diagrams showing the results of explorations with the miniature electrodes in the Pickna well-______________-______ 17

6. Cloudburst storm in upper part of Republican River drainage

basin, May 30-31, 1935____ _ _ _______________ 28

7. Map of La Canada Valley and vicinity__________________ 57

8. Mean rate of rainfall for 5-minute periods____________ 62

9. Rainfall records for Opids Camp, Mount Lukens, and Flintridge stations_______________________________________ 64

10. Graphs showing rainfall of New Year's storm, profile showing 

location of rain gages, and relation between rates of rainfall 

and run-off on an experimental plot in Pickens Canyon____ 66

11. Profile of Pickens Creek_______________________ 70

12. Movement of debris in Pickens Canyon__________________ 78

13. Movement of debris wave across debris cone of Pickens Creek_ 85

14. Debris wave on Pickens Creek debris cone_________________ 86

15. Sieve analyses of debris________________________________ 89

16. Action of debris wave on check dam in Haines Canyon______ 91

17. Map of Utah and part of Idaho showing areas covered by

ground-water investigations---------------------------- 102
ILLUSTRATIONS VH

Page 

FIGURE 18. Average monthly precipitation at Huntsville, Utah_____ __ 105

19. Stream flow in Ogden Valley, 1925-26________.__. 113

20. Total surface-water outflow from Ogden Valley, Utah, 1894,

1921, 1925, 1928, 1932, 1933, and 1934______.______ 115

21. Diagrammatic sketch of an ideal east-west section through

Ogden Valley, Utah, showing ground-water conditions.... 119

22. Profiles between Artesian Park and well 74, Ogden Valley, 

Utah, showing land surface and levels at which water stood 

in wells on May 31, 1933, and October 10, 1934._________ 121

23. Discharge from wells at Artesian Park and water levels in three

wells in Ogden Valley.________________________________ 125

24. Hydrographs of streams and wells in Ogden Valley, Utah,

showing effects of plant transpiration on water levels______ 127

25. Hydrograph of well 81 and graph of fluctuation of atmospheric 

pressure in Ogden Valley, Utah, showing barometric type of 

water-level fluctuation_____________________________ 128

26. Hydrographs of five wells in Ogden Valley, Utah, showing 

fluctuations of water levels in wells caused by earthquakes on 

March 12, 1934._____.____-____-_-__-__.______________ 129

27. Graph from recording pressure gage operating on a 133-foot 

artesian well in Ogden Valley, Utah, showing effect of earthquake of March 12, 1934_______________________ 130

28. Index-map of Arizona showing area covered by the present 

report and by other water-supply papers of the Geological 

Survey__--_--__._____-__________________ 164

29. Index map of Arizona, showing area considered in this report

and other water-supply papers of the Geological Survey. _ _ _ _ 184

30. Section showing artesian conditions in the lake beds of the

valley of the Gila River and San Simon Creek__________ 210

31. Map of Puna, showing location of wells__________________ 211

32. Map of Safford, showing location of wells._________________ 212

33. Map of Thatcher, showing location of wells._______________ 213

34. Isohyetal map of the Seco Creek drainage basin above D'Hanis. 235

35. Hydrographs of discharge, Colorado River near San Saba, at

Austin, at Smithville, and near Eagle Lake, June 14-24,1935. 242

36. Isohyetal map of the Llano River Basin.___________ ..___ 244

37. Hydrographs of discharge, North Llano River near Junction, 

Llano River near Junction, and Llano River near Castell, 

June 14-17, 1935__________________________ 246

38. Hydrographs of discharge, Nueces River at Laguna, near

Uvalde, at Cotulla, and near Three Rivers, June 14-27,1935. 248

39. Isohyetal map of the West Nueces River Basin ______________ 251

40. Profiles of high-water marks and sections of slope-area reach

on the West Nueces River near Brackettville_________ 253

41. Isohyetal map of the Buffalo Bayou Basin_______._________ 278

42. Hydrograph of discharge, Buffalo Bayou at Eureka Cutoff

railroad bridge at Houston, December 7-12, 1935_________ 279

43. High-water and stream-bed profiles of Buffalo Bayou from

Post Oak Road to the turning basin at Houston._________ 281

58805 39 6
TABLES

INSERT

Page 

Records of wells in Graham County, Ariz_.___________________________ 222

TABLES

Paste 

TABLE 1. Precipitation records for June 1-15, 1935.__________________ 238

2. Altitude and average descent of the Colorado River from a

point near San Saba to the mouth__________________ 240

3. Maximum discharge at river-measurement stations on the Colorado and Pedernales Rivers, June 1935_______________ 241

4. Altitude and average descent of the North Llano, South Llano,

and Llano Rivers from source to mouth__ -___ _ _ 243

5. Maximum discharge determined at places in the Llano River

Basin, June 1935.____...___________________ 245

6. Altitude and average descent of the Nueces River from source

to mouth___________________________________________ 247

7. Maximum discharge at river-measurement stations on the

Nueces River, June 1935____________________ 249

8. Altitude and average descent of the West Nueces River from

source to mouth_______________________________ 250

9. Computations for slope-area determination of discharge of the

West Nueces River near Brackettville__________________ 252

10. Precipitation in Buffalo Bayou and adjacent drainage basins,

December 6-8, 1935______________ __ .__ 277

11. Maximum discharge, Buffalo Bayou and tributaries, at Houston, December 9, 1935_____________________ 277

12. Run-off and discharge on Buffalo Bayou at Eureka Cutoff

Bridge, Houston, December 7-12, 1935__ 280

13. Crest stages, flood of December 9,1935, and stream-bed altitudes

determined June 1929, Buffalo Bayou at Houston._____ 282 

14. Maximum stages and discharges on certain streams in Texas. _ 283

o
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UNITED STATES DEPARTMENT OF THE INTERIOR 

Harold L. Ickes, Secretary

GEOLOGICAL SURVEY 

W. C. Mendenhall, Director

Water-Supply Paper 796 A

METHODS OF LOCATING SALT-WATER 

LEAKS IN WATER WELLS

BY

PENN LIVINGSTON AND WALTER LYNCH

Prepared in cooperation with the 

TEXAS BOARD OF WATER ENGINEERS

Contributions to the hydrology of the United States, 1937 

(Pages 1-20)

UNITED STATES

GOVERNMENT PRINTING OFFICE 

WASHINGTON : 1937

For sale by the Superintendent of Documents, Washington, Dt. C. ------ Price 10 cents
CONTENTS

Page

Ab stract........................................................... 1

Introduction....................................................... 1

Areas studied..........................................*. ...... 3

Methods of investigation........................................... 3

Pumping method............................... « ... «* 4

Velocity method............................................... 8

Sampler method................................................ 10

Electrical-conductivity method................................ 12

Sampler-electrodes and Wheatstone bridge.................. 14

Miniature electrodes...................................... 15

Additional characteristics................................ 18

Summary of results with the electrical-conductivity method 19

Construction of wells to avoid contamination by salt water......... 19

ILLUSTRATIONS

Plate 1. A_, Section of a pump column showing the effect of corrosion by salt water; B, Well casing showing holes made 

by salt water.......................................... 6

2. A, Deep-well current meterj 13, Power-driven winch used

for lowering and raising equipment In wells............ 6

3. A, Deep-well water sampler with electrodes used in Winter 

Garden area, Tex.j 13, Deep-well water samplers used in 

Sarasota County, Fla................................... 6

4. A, Cross section of deep-well water sampler used in Winter Garden area, Tex.j B, Cross section of deep-well 

water sampler used in Kleberg County, Tex.; £, Cross 

section of deep-well water sampler used in Sarasota 

County, Fla............................................ 6

5. A, Wheatstone bridge used in Winter Garden area, Tex.j

B_, Apparatus used to explore wells in Sarasota County, 

Fla.................................................... 14

6. A., Diagram of Wheatstone bridge direct-current electric

circuit used £n Winter Garden area, Tex.} B, Diagram of 

milliammeter direct-current electric circuit used in 

Kleberg County, Tex.; J3, Diagram of Wheatstone bridge 

alternating-current electric circuit'used in Sarasota 

County, Fla............................................ 14

? Jk> Equipment with miniature electrodes used in Winter

Garden area, Tex.; B, Hand-operated apparatus used to 

explore wells in Kleberg County, Tex................... 14

8. A_, Cross section of miniature electrodes used in Winter 

Garden area, Tex.j B, Cross section of miniature electrodes used In Kleberg County, Tex. and in Sarasota 

County, Fla............................................. 14

9. Diagrams showing locations of salt-water leaks in water 

wells in Kleberg County, Tex., indicated by the miniature electrodes-milliammeter equipment................. 14

Figure 1. Diagram showing fluctuations in chloride content of

water pumped from the Pickna well in the Winter Garden 

area, Tex............................................. 5

2. Diagram showing fluctuations In chloride content of

water pumped from the Pollard well after the well had 

been repaired......................................... 7

3. A, Chloride content (parts per million) of samples

brought up by the deep-well sampler from the E. C. 

Smith well near Catarina, Tex.; B, Resistance of the 

water at different depths in the~!E. C. Smith well as 

indicated by the Wheatstone bridge.................... 11

4. Diagrams showing the effect of varying the voltage on

the resistance and conductivity of saline watera...... 15

5. Diagrams showing the results of explorations with the

miniature electrodes in the Pickna well............... 17

II
CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES, 1937

K. C. Grover, Chief Hydraulic Engineer

METHODS OP LOCATING SALT-WATER LEAKS IK WATER WELLS

By Perm Livingston and Walter Lynch

Abstract

In localities where highly mineralized water is present in beds above 

and below the beds that yield the supplies of fresh water it is necessary 

to be able to locate leaks in wells in order to know whether the wells are 

being contaminated through holes in the casings or whether the fresh water 

supply is failing. Pour general methods of detecting salt-water leaks 

hare been used. In the pumping method, samples taken at measured time intervals while the well is being pumped show by their progressive change in 

salinity if salt water is being drawn in. In the velocity method, which 

is suitable for use only in artesian wells, a current meter lowered into 

the well indicates the location of possible salt water leaks by determining the levels at which there are changes in the rate of upward movement 

of the water. In the sampler method a container lowered into the well 

brings up a sample from any depth desired for analysis of its chloride 

content. The electric conductivity method, for which special apparatus 

was designed, has been used successfully in the Winter Garden area and 

Kleberg County, Tex., and in Sarasota County, Pla. The procedure in this 

method was to lower a pair of insulated electrodes into the well and 

measure the resistance of the water between them with the Wheatstone 

bridge or, in waters low in chloride, to apply a direct current of low 

voltage and measure the current flowing between .the electrodes by means 

of a milliammetsr. The instruments showed & marked increase in the conductivity of the water as the electrodes passed from fresh to salt water 

in the well, leaving no doubt as to the location of the leaks.

INTRODUCTION

During recent years the United States Geological Survey has been 

called upon to investigate several areas in which the water obtained from 

wells has been contaminated by salt water. Many of these water supplies 

are vitally important for industry, public supplies, or irrigation, and 

the infiltration of highly mineralized water has proved objectionable.

In addition to the damage represented by the loss in yield and 

quality of crops irrigated with highly mineralized water, much more serious loss may result through the ultimate abandonment of valuable farm 

lands that become so heavily saturated with salt that further crop production from them is impossible. Definite limits for the content of salt

I/ Burgess, P. S., Alkali soil and methods of reclamation: Univ. 

Arizona Bull. 12, 1928.
2 CONTRIBUTIONS TO HYDROLOGY, 1937

In water to be used for Irrigation have not been determined, as the limit 

of safety Is subject to wide variation: much depends upon the character

of the soil, the drainage of the soil, the quantity of water used, and the

2/ 

frequency of the irrigation. Highly mineralized water is unfit for use

in boilers, for ice making, and for other industrial uses. The contamination by salt water of wells used for public supplies presents a serious 

problem to municipalities dependent upon such sources, especially where 

it seems probable that some of the wells that have been developed at considerable expense may have to be abandoned. To be suitable for domestic

3/ 

use water should not contain over 250 parts per million of chloride

(one of the two elements of common salt, sodium chloride) and preferably 

should contain much less than this amount. A chloride content of 400 to 

500 parts per million, however, though noticeable to the taste, is not 

especially disagreeable, and human beings can tolerate water containing 

more. Ordinary ocean water contains between 19,000 and 20,000 parts per 

million of chlorides.

Salt water has a highly corrosive action on well casing, thereby 

shortening the life of the well. It also corrodes the pumping equipment, 

thus reducing the efficiency of the pump, and increasing the cost of 

operation. Ultimately the loss of efficiency and increased cost of operation become so great that the pumping equipment must be removed from the 

well and repaired at considerable expense.

It is evident, therefore, that the contamination by salt water of a 

water supply obtained from wells represents a serious problem that may 

affect vitally the economic future and possibly the very existence of entire communities. Much concern has been expressed by residents in such 

localities as to whether the fresh-water reservoir is becoming contaminated or whether highly mineralized water from some upper water-bearing 

bed is entering the well because of faulty well construction. As very 

little work had been done in this field of investigation it became necessary to develop methods for determining the extent of the contamination 

and the points at which the highly mineralized water entered the wells. 

It is the purpose of this paper to present the various methods that have 

been used in studying the problem.

2/ Scofield, C. S., The alkali problem in irrigation: Smithsonian 

Inst. Ann. Rept., 1921, pp. 213-223. Breazeale, J. P., A study of the 

toxicity of salines that occur in black alkali soils: Arizona Univ. 

Bull. 14, 1927.

3/ Drinking-water standards, U. S. Public Health Service, 1925.
METHODS OP LOCATING SALT-WATER LEAKS IN WELLS 3 

AREAS STUDIED

Among the areas in which contamination of wells lay salt water has 

been studied lay the United States Geological Surrey are the Atlantic Oity 

area, N. J., the Winter Garden area and other areas in southwestern 

Texas, Sarasota County, Fla., and areas in Iowa.

The work in southwestern Texas was done by the Geological Survey in 

cooperation with the Texas Board of Water Engineers as part of the study 

of ground-water resources of the State. Explorations of wells with the 

current meter were made lay A. G. Fiedler and Penn Livingston in the Winter Garden area in July 1930, and the electrical-conductivity method was 

developed and used in that area by Mr. Livingston and Walter Lynch in the 

fall of 1930 and in 1931. The experience gained was utilized in designing the apparatus used in KLeberg County, Tex. in the winter of 1932-33

by Mr. Livingston and T. W. Bridges and that used in Sarasota County, Pla.

i/ Pla., in 1932 by V. T, Stringfield and Mr. Piedler. These investigations were conducted under the general direction of 0. E. Meinzer, geologist in charge of the division of ground water, United States Geological 

Survey.

In October 1934 a survey of wells in Iowa that yield highly mineralized water was begun by the Iowa Geological Survey in cooperation with 

the United States Geological Survey, and the equipment used in Florida 

was made available for that investigation.

In view of the fact that some of the apparatus was designed for 

specific projects, all the apparatus will be described and the results 

discussed.

METHODS OP INVESTIGATION

There are four general methods of locating salt-water leaks in 

wells. For convenience the methods may be designated the pumping method, 

the velocity method, the sampler method, and the electrical-conductivity 

method. The pumping method consists of pumping the well and noting the 

change that takes place in the salt content of the water discharged from 

the well as pumping progresses. In the velocity method the location of 

leaks is determined by finding with a current meter the place at which

4/ Stringfield, V. T., Exploration of artesian wells in Saraaota 

County, Fla.i Florida Geol. Survey 23d-24th Ann. Kept., pp. 195-227, 

1953. Fiedler, A. G., Deep-well salinity exploration: Am. Geophys. 

Union Trans. 14th Ann. Meeting, pp. 478-480, June 1933.

126963 () 37 2
4 CONTRIBUTIONS TO HYDROLOGY, 1937

any measurable movement of water takes place in the wellj to use this 

method in a flowing well it is desirable to extend the well casing above 

the surface until the flow ceases. In the sampler method water samples 

are taken at different depths in the well and their salt content determined. The electrical-conductivity method is based upon the principle 

that salt in water increases its electrical conductivity; by observing 

the depth in the well where the electrical conductivity of the water increases markedly it is possible to determine where the salt water enters.

Pumping method

In the pumping method samples of water are taken at frequent 

measured time intervals, beginning with the starting of the pump. The 

first samples are taken at intervals of a few seconds} later the intervals are lengthened because the salinity of the water usually becomes 

more nearly uniform as pumping continues. The samples are tested for 

chloride with an ordinary field outfit of silver nitrate and potassium 

chromate solutions. Then curves are plotted showing the change in 

salinity that occurs in the water as pumping progresses. The best results are obtained when the tests are run after the wells have been idle 

for some time.

The pumping method of investigation is applicable only to the study 

of -wells that can be pumped readily or that have a natural flow. It 

serves admirably to show the degree of contamination by salt water and 

whether or not the salt water is entering through the fresh-water beds. 

It is not possible with this method to locate the exact position of a 

leak in the casing, but in many wells the approximate position of the 

leak can be determined by noting the quantity of water discharged between 

the starting of the pump and the appearance of salt water in the discharge.

In the Atlantic City area, where the beds yielding fresh water are

5/ 

overlain by beds containing salt water, Thompson used the pumping method

to determine whether the salt-water contamination occurred by direct 

leakage from a salt-water formation through the casing of the well being 

pumped; whether the salt water came from nearby wells into which there 

was salt-water leakage; or whether the contamination was due to direct 

percolation of salt water into the fresh-water formation.

5/ Thompson, D. G., Ground-water supplies of the Atlantic City 

region: New Jersey Dept. Cons, and Devel. Bull. 30, pp. 96-112,
METHODS OP LOCATING SALT-WATER LEAKS IN WELLS

In the Winter Garden area of Texas the formation yielding the fresh 

water lies between two formations that ordinarily contain water that is 

highly mineralized, chiefly by common salt. Therefore, most of the wells 

must be tightly cased through the overlying formation to exclude undesirable water from above, and they should not be drilled into the underlying 

formation. In this area the pumping method was used successfully in 

about 40 wells and showed in every test that the salt water was coming 

through defective casings and not from the fresh-water formation. In 

nearly all the wells the test gave definite information regarding the 

size of the leak.

£.£UV

2000 

§ 1800 

ZJ 1600

5 1400 CC

UJ 0_ 1200

£2 1000 

% £ 800

y" 600

0 400

_i

5 200 

0

iIn <j

B

<

1

1o

Q.

E

c£

-1

o

fe{

i

41-4

Well pumped at the rate of 250 gallons a minute, 

o Indicates time at which sample was taken.

k

V- -. -^> : 0-.

1a. 

o

1o 

o_

£ 

(X

S3

0 I 3 5 7 9 II 13 15 17 19 21 23 25 27 29 31 

MINUTES AFTER PUMPING WAS STARTED

Figure 1. Diagram showing fluctuations in chloride content 

of water pumped from the Pickna well in the 

Winter Garden area, Texas.

A typical time-salinity curve showing the chloride content of samples of water obtained during a pumping test of a well belonging to 

J. Pickna, 4 miles east of Winter Haven, is shown in figure 1. The well 

was drilled in 1912 and has 1,070 feet of 8-inch casing. The graph shows 

that the water discharged by the pump during the first three-quarters of 

a minute averaged about 700 parts per million of chloride. Toward the 

end of the first minute the chloride suddenly increased to 2,100 parts 

per million, then dropped to an average of about 1,900 parts per million 

for the next 3 minutes. During the fifth minute it dropped to 800 parts, 

then continued to decline until at the end of 20 minutes it had dropped
6 CONTRIBUTIONS TO HYDROLOGY, 1937

to 260 parts per million, which was even lower than at the start of the 

test. The curve indicates that when the pump was shut down prior to the 

test the well was filled with water of low salinity. While the pump was 

idle salt water entered the well somewhere near the top and, being 

heavier, settled down into and displaced the fresh water; the salt water 

not only reached all parts of the well below the point at which it entered but also migrated into some of the fresh-water sand around the well. 

When the pump was started the comparatively fresh water in the well above 

the leak was discharged first, and as the whole column of water in the 

well moved upward the pump picked up the salt water and finally the fresh 

water from the bottom. Had pumping continued the salt content would 

probably have continued to decrease very slowly for some time. The test 

shows very definitely the presence of a leak in the casing in the upper 

part of the well, but not the exact depth of the defect.

Pumping tests were made on a well belonging to the Bassett ranch, 

1-| miles southeast of Carrizo Springs, Tex. The well was drilled in 1924 

and has 480 feet of 10-inch casingo Plate 1, A, shows one of three holes 

in a 20-foot piece of pump column that was removed from the well. The 

entire 20-foot piece was badly corroded and several depressions in it 

would soon have developed into additional holes. The pumping tests on 

this well showed progressive changes in the chloride content of the water 

similar to those in the Pickna well, described above, and tests with the 

electrical apparatus showed that salt water was entering the well through 

holes in the well casing opposite to those in the pump column.

After a defective well has been repaired the pumping method can be 

used to determine whether the leak has been stopped, as in a well belonging to 0. Pollard, 6j miles southeast of Carrizo Springs, Tex. The well 

was drilled in 1927 and was repaired in the winter of 1929-30; it is 677 

feet deep and has 10-inch casing. Plate 1, B_, shows two holes in a piece 

of defective casing that was removed from the well. The holes had an 

area of about 6 square inches and were near the end of a joint of casing, 

just above the coupling, at a depth of 212 feet. After the new casing 

was installed the well was pumped and the water tested at intervals over 

a period of more than 2 months. Figure 2 shows the time-salinity curve 

compiled from the results of the tests during periods of pumping aggregating 118 hours.

The pump was again started after the completion of the repairs and 6 

hours later the water contained about 3,800 parts per million of chloride.
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 7S6 PLATE 1

A. SECTION OF A PUMP COLUMN SHOWING THE EFFECT OF CORROSION BY SALT

WATER.

B. WELL CASING SHOWING HOLES MADE BY SALT WATER.
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 796 PLATE 2

A. DEEP-WELL CURRENT METER.

B. POWER-DRIVEN WINCH USED FOR LOWERING AND RAISING EQUIPMENT IN WELLS.
U S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 796 PLATE 3

A. DEEP-WELL WATER SAMPLER WITH ELECTRODES USED IN WINTER GARDEN

AREA, TEX.

B. DEEP-WELL WATER SAMPLERS USED IN SARASOTA COUNTY, FLA.

U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 796 PLATE 4

Electrodes

Carriage bolt 

Bakelite

3/4by y 

straps

Leather

Lowering 

cable 

Messenger 

weight 18 oz.

Dogs

Rubber 

plug

Cable guide

Drilled 0.09 

to fit cable

Standard 

pipe plug split

2"diam. 

~~Outer tube

B Cable clamp'

Rubber , 

seat 2" by 72

 Drain

CROSS SECTIONS OF DEEP-WELL WATER SAMPLERS. 

A, Water sampler used in Winter Garden area, Tex.; B, Water sampler used in Kleberg County, Tex.; C, Water sampler used in Sarasota County, Fla.

METHODS OP LOCATING SALT-WATER LEAKS IN WELLS

At the end of 118 hours of pumping the salinity had been reduced to 130 

parts per million, which was close to the average for the locality. The 

curve indicates that the water-bearing sands supplying the well were 

filled with salt water for some distance around the well, but as pumping

4000

3500

40 60 80 

PUMPING TIME IN HOURS

100 120

Figure 2. Diagram showing fluctuations in chloride content 

of water pumped from the Pollard well after the 

well had been repaired.

progressed fresh water was gradually drawn toward the well and displaced 

the salt water. The salt content of the water decreased as pumping proceeded and did not rise noticeably at any time, even though the pumping
8 CONTRIBUTIONS TO HYDROLOGY, 1937

was not continuous; therefore it waa evident that the repairs were 

satisfactory,

Velocity method

6/

According to Meinzer the velocity or current-meter method of exploring wella was used by W, G. Sloan, of the United States Department of 

Agriculture, and W. B. Heroy, of the United States Geological Survey, in

connection with drainage investigations on the Twin Palls South Side

6/ 

project, in Idaho, from 1910 to 1914. The exploration of wells with a

current meter in Honolulu, Hawaii, and near Roswell, N. Mex., for the 

purpose of determining the location of underground leaka that were wastu ing artesian water haa been described by McCombs and Piedler. The 

artesian head in the water-bearing formationa tapped by the wells .in both 

of these areas was relatively high, and the leakage was normally from the 

well into a formation containing water under a lower head. The location 

of the leaks was established by lowering the meter into the well and determining the places above the main water-bearing formation at which 

there wag a change in the rate of upward movement.

The following description of the deep-well current meter, the essential parts of which are shown in Plate 2, A, is quoted from the report by

§/ Piedler on the use of this equipment in the Roswell artesian basin.

The Au deep-well current meter ia essentially a turbine 

wheel mounted within a cylindrical brass case, which is suspended in a 3-inch pipe and is lowered into the well and removed 

from the well by means of a cable and reel. Near the lower end 

of the brass meter case, on the inside, is mounted a pointed 

bearing upon which the wheel revolves. This pointed bearing is 

provided with a movable nut which ia turned up when the meter is 

not in use, thereby removing the turbine wheel from the bearing 

and preventing it from being damaged. At the upper end of the 

brass cylinder there is a movable frame which supports a single 

or a pentapoint commutator head like thoae used in the Price current meter. These commutator heads are interchangeable, and either 

may be used according to the velocity of the water in the well. 

The vanes of the turbine are made of aluminum. The lower bearing 

of the wheel ia a pivot cup of hard steel, and the upper shaft is 

made of unhardened tool steel. The upper shaft is drilled and 

tapped to accommodate the standard Price cam and worm screw to be 

used with the single and pentapoint heads, respectively.

Before being taken to the field the meter was rated to determine the 

relation between the velocity of the water and various speeds of the turbine wheel, and a rating table was compiled. The meter is lowered into 

and raised from the well by means of a cable and a winch mounted on a

6/ Meinzer, 0. E., Outline of methods for estimating ground-water 

supplies: TJ. S. Geol. Survey Water-Supply Paper 638, p. 125, 1932.

7/ McCombs, John, and Piedler, A. G., Methods of exploring and repairing leaky artesian wells: TJ. S. Geol. Survey Water-Supply Paper 596, 

pp. 1-32, 1927.

8/ McCombs, John, and Piedler, A. G., op. cit., pp. 25-26.
METHODS OP LOCATING SALT-WATER T.BATTS IK WELLS 9

truck and driven by a belt attached to a wheel of the truck. (See pi. 

2, 13.) The cable pasaea over a wheel with a counter that indicates at 

any time the depth of the meter in the well. The cable has a diameter 

of seven thirty-seconds of an inch and is composed of six strands of 

seven wires each of galvanized aircraft wire, wound around an insulated 

core of seven no. 38 annealed copper wires. The meter is electrically 

connected with the surface equipment, a circuit being established by 

means of a dry cell, the double conductor cable, and a set of earphones 

worn by the observer. At each revolution of the turbine wheel the circuit is closed and opened in the commutator head of the meter, causing a 

click in the earphones. The velocity of the water at any point in a 

well may be readily determined by timing with a stop watch the clicks

registered in the earphones and applying the rating table.

2/ An extensivs series of tests was made in 1933 and 1934 in the hydraulic laboratory of the National Bureau of Standards to rate and determine the operating characteristics of the deep-well current meter, 

especially with respect to the action of the meter in a well near a leak 

or a change in the size of casing. These tests, which simulated field 

conditions as closely aa possible, covered a wide range of flows in casings from 3 to 12 Inches in diameter.

In the greater part of the Winter Garden area of Texas formations 

containing salt water lie above the fresh-water formation, and the salt 

water enters the wells during periods when the head of the fresh water 

is low. It was therefore reasoned that the entrance of salt water into 

the well should be accompanied by movement of water in the well in the 

vicinity of the leak and that the deep-well current meter might indicate 

this movement. Equipment of the same type as that used in the Roswell 

area was therefore tried out in the study of the salty wells in Texas. 

Considerable difficulty was experienced in introducing the current meter 

into the wells because of the presence of pumping equipment or other obstructions, but during July and August 1930 meter explorations were successfully carried out in 23 wells, most of which were known to be contaminated to some extent with salt water. In none of them, however, was 

a movement of water encountered sufficient to turn the meter. As the 

tests were made at a time of the year when the head of the fresh water

£/ Report on investigation of deep-well current meters for waterresources branch, U. S. Geological Survey: Nat. Bur. Standards unpublished report, pp. 1-76, 1934.
10 CONTRIBUTIONS TO HYDROLOGY, 1937

was at Its highest, It Is probable that there was very little difference 

between the head of the salt water and that of the fresh water. Although 

the Information obtained was negative In character, It was believed to 

be sufficient to warrant the conclusion that the underground leakage of 

water from defective wells or into defective wells was not very great 

at the time the explorations were made.

In Saraaota County, Pla., also, the tests with the meter indicated 

that no great amount of leakage was taking place In the wells that were 

examined. In some of the flowing wells in that area the meter showed 

that the water In the bottom 100 to 200 feet of the wells was not moving. 

This suggests that the wells bad been drilled deeper than was necessary.

Sampler method

In the sampler method of locating salt-water leaks a container is 

lowered Into the well, and samples are obtained at any depth desired. 

For work in the Winter Garden area a sampler was assembled consisting 

essentially of an 18-inch length of 3-lnch galvanized pipe provided 

with a leather flap valve at the top and the bottom. (See pi. 3, A, 

and 4, A.) This sampler was lowered to the desired depth with the cable 

and winch used In the explorations with the current meter. Then the 

cable was given a few short pulls by hand so as to cause the sampler to 

move up and down rapidly through a distance of about a foot. Experiments showed that the water in the sampler was completely changed in 

about 10 such up-and-down movements, but In the sampling operations 

about 75 pulls were given to Insure thorough flushing. In removing the 

sampler from the well care had to be exercised to insure that it moved 

continuously upward. If a reversal in the movement took place the 

valves opened and the water was lost.

Among the wells tested with the sampler in the Winter Garden area 

was one belonging to E. C. Smith, 8 miles southwest of Catarlna. The 

chloride content of the samples obtained from the well plotted against 

the depth at which the samples were taken indicates that water containing about 6,000 parts per million of chloride was entering the 

well at a depth of about 180 feet. (See fig. 3 A.)

For work in Eleberg County, Tex., it was desirable to have a small 

sampler that could be handled with the light portable electrical equipment. A sampler of the flap-valve type using a 1^-lnch pipe about 14
METHODS OP LOCATING SALT-WATER LEAKS IN WELLS 11

Inches long proved very satisfactory for this investigation. (See pi. 

4, 13.) The sampler is clamped to the supporting cable by means of a 

1/8-inch pipe plug that has been drilled to the siae of the cable 

(0.09 inch) and split. With this arrangement the sampler can be removed or attached at will and without disturbing the electrodes.

200

400

800

1000

1200

1400

5- Leak

2000 4000 6000 

CHLORIDE, PARTS PER MILLION

A

30 40 

RESISTANCE IN OHMS

B

Figure 3.--A, Chloride content (parts per million) of samples 

brought up by the deep-well sampler from the E. C. 

Smith well near Catarina, Tex.; B, Resistance of 

the water at different depths in the E. C. Smith 

well as indicated by the Wheatstone bridge.
12 CONTRIBUTIONS TO HYDROLOGY, 1957

The flap-valve type of sampler is satisfactory for nonflowlng wells 

and perhaps for -wells having a small flow but Is not adapted to wells 

that have a strong flow. A special water sampler was designed for wells 

of large flow and used In Sarasota County, Pla. A view of It Is shown at 

the left In plate 3, B. and a cross section In plate 4, C_. It consists 

of two brass cylinders, an outer one 3 1/8 Inches In diameter and an Inner one 2 inches in diameter. The cable is securely fastened to the bottom of the outer cylinder by means of a spider connection and cable clamp 

and passes through a tube at the center of the inner cylinder. The inner 

cylinder is free to slide up and down the cable a distance of a few 

inches. When lowered into a flowing well the sampler is in the open position shown in plate 4, C_. In this position the rubber stopper above the 

cylinder is held in place by dogs that are hooked over the top of the 

guide tube, and the inner cylinder is held up by a small chain attached 

to the stopper, thus allowing the water to flow freely through the apparatus. When a water sample is desired, a messenger weight is sent down 

the cable to unhook the dogs, permitting the inner cylinder to drop onto 

the plug at the bottom and also permitting the top stopper to settle down 

and close the top of the cylinder.

Electrical-conductivity method

The principle of determining the salinity of water by measuring its 

electrical conductivity has been applied in connection with the determination of soluble salts in soils by the United States Department of io/

Agriculture and also in connection with the measurement of the salinity

!!/ i§/ of sea water by the United States Coast Ouard. Slichter applied this

1Q/ Whitney, Milton, and Means, T. H., An electrical method of determining the soluble salt content of soils: U. S. Dept. Agr., Div. Soils, 

Bull. 8, 1897. Briggs, L. J., Electrical instruments for determining the 

moisture, temperature, and soluble salt content of soils* U. S. Dept. 

Agr., Div. Soils, Bull. 15, 1899. Davis, R. 0. E., and Bryan, Harry, The 

electrical bridge for the determination of soluble salts in soils: U. S. 

Dept. Agr.. Bur. Soils, Bull. 61, 1910. Davis, R. 0. E., The use of the 

electrolytic bridge for determining soluble salts: U. S. Dept. Agr. Giro. 

423, 1937.

ll/ International ice observations and ice patrol service, season of 

1921jU. S. Coast Guard Bull. 9. Idem, season of 1924: U. S. Coast 

Guard Bull. 12. Wenner, Prank, Smith. E. H., and Soule, F. M., Apparatus 

for the determination aboard ship of the salinity of sea water by the 

electrical-conductivity method: Nat. Bur. Standards Research Paper 223, 

1930.

12/ Slichter, C. S., The motions of underground waters U. S. Geol. 

Survey~Water-Supply Paper 67, pp. 48-51, 1902; Description of underflow 

meter used in measuring the velocity and direction of movement of underground water: U. S. Geol. Survey Water-Supply Paper 110, pp. 17-31, 

1905| Field measurements of the rate of movement of underground water: 

U. S. Geol. Survey Water-Supply Paper 140, pp. 9-85, 1905.
METHODS OF LOCATING SALT-WATER LEAKS IN WELLS 13

principle in his electrical method of measuring the rate of movement of 

ground water. Other research workers have studied the relation of the 

electrical conductivity of solutions to their dissolved solids and have 

performed many tests. Some of the research work in connection with the

conductivity of sea water and the results obtained are briefly dis12/ cussed by Service. So far as the writers know this method was first

used in determining the location of salt-water leaks in wells in the 

Winter Garden area of Texas. The method was introduced in that area because the pumping and velocity methods, though providing information of 

definite value, did not serve to establish within reasonably close 

limits the location of the salt-water leaks in the wells.

The electrical-conductivity method is based upon the fact that the 

conductivity of water increases with an increase in the dissolved solids. 

As the great difference in total dissolved solids between the fresh 

water and the contaminating water is made up chiefly of chloride salts, 

an increase in conductivity indicates greater salinity. The procedure, 

therefore, is to lower two electrodes, or insulated pieces of metal, 

into a well and to determine the degree of conductivity of the water 

between them. Considerable experimental work was done with various 

types of electrodes and electrical measuring apparatus before the equipment described below was assembled. Two sizes of electrode equipment 

were constructed a large set mounted in the water-sampler cage, to be 

used in open wells and handled with the power-driven winch, and a 

miniature set, to be used in wells in which the pumping equipment is 

still in place and it is therefore impossible to lower the large set. 

The electrical measuring devices are of three types a Wheatstone 

bridge to measure the resistance of water to current, a Wheatstone 

bridge to measure the resistance of water to alternating current, and a 

milliammeter to measure the direct current between the electrodes. 

A diagram of each of the circuits is shown in plate 6, the Wheatstone 

bridge used in the Winter Garden area is shown in plate 5, A, and apparatus uaed in Sarasota County, Fla., is shown in plate 5, B. Although, 

any of these electrical measuring devices will give satisfactory results 

with either of the electrodes described in this report, the principal 

arrangement used in each investigation will be discussed.

13/ Service, J. H., Measurement of salinity of aea water: U. S. 

Coast and Geodetic Survey Special Pub. 147, 1928.
14 CONTRIBUTIONS TO HYDROLOGY, 1937

Sampler electrodes and Wheatstone bridge

The large set of electrodes and Wheatstone bridge were first used in 

the Winter Garden area. The apparatus consists of a pair of electrodes 

mounted on the top of a cage attached to the upper end of the water sampler. (See pis. 3, A, and 4, A.) The upper cross brace of the cage 

forms one of the electrodes; the other consists of a ^-inch carriage bolt 

that is held in place and insulated from the frame by means of a strip of 

bakelite bolted to the sides of the cage. The space between the two 

electrodes is five-eighths of an inch. The lower electrode is connected 

to the insulated core of the cable, and the upper one is grounded to the 

steel strands of the hoisting cable.

The Wheatstone bridge was constructed chiefly from spare radio and 

meter-testing parts. The circuit, as shown in plate 6, A_, is made up of 

two fixed resistances of 400 ohms each, a variable resistance having a 

maximum value of 400 ohms, and the resistance of the water between the 

electrodes. A radio C battery of 4j volts is used to supply the current , 

In operating the equipment the variable resistance is adjusted to keep 

the galvanometer in the neutral position. The galvanometer is a Leeds & 

Northrup portable instrument of the wire suspension type. A key switch 

is used in the meter circuit. Only four connections need to be made in 

setting up the bridge two leads are connected to the cable through the 

brushes on the hoisting drum and two to the battery, and it is immaterial 

which way the cable leads are connected.

Tests were made by means of the water sampler equipped with electrodes and the Wheatstone bridge on a well belonging to E. C. Smith, 8 

miles southwest of Catarina; this well is 10 inches in diameter and 1,655 

feet deep and was drilled in 1928. The chloride content of the samples 

of water is indicated in figure 3, A, and the electrical conductivity of 

the water in figure 3, B. The electrical resistance indicated by the apparatus was constant at about 42 ohms from the top of the water column to 

a depth of about 170 feet below the ground. It dropped suddenly to 24 

ohms at a depth of about 180 feet and remained at about that figure to a 

depth of about 900 feet. The resistance increased steadily below about 

900 feet and reached 38 ohms at about 1,100 feet, below which it again 

remained constant. Both the sampler test and the electrical-conductivity 

test indicated that salt water was leaking through the casing of this 

well at a depth of about 180 feet below the ground. Salt water from the
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 796 PLATE 5

A. WHEATSTONE BRIDGE USED CN WINTER GARDEN AREA, TEX.

B. APPARATUS USED TO EXPLORE WELLS IN SARASOTA COUNTY, FLA.
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 796 PLATE 6

-till'

DIAGRAMS OF ELECTRIC CIRCUITS.

A, Wheatstone bridge direct-current electric circuit used in Winter Garden area, Tex.; B, Milliammeter direct-current electric circuit used in Kleberg County, Tex.; C, Wheatstone bridge alternating-current electric circuit used in Sarasota County, Fla.
TJ. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 796 PLATE 7

W* 1WW.I..* -1. I TTT^F f. I »--.* -

EQUIPMENT WITH MINIATURE ELECTRODES USED IN WINTER GARDEN AREA

TEX.

B HAND-OPERATED APPARATUS USED TO EXPLORE WELLS IN KLEBERG COUNTY

TEX.
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 796 PLATE 8

)9 cable 

to drum

Steel strands 

X'soldered to 

tube

Sealing wax

_NIo. 14 cop- 

~ per wire

3/8 O.D. copper tubing

,T

-Lead

.09 cable with insulated copper 

core

y '2 machine screw

Insulation

_Sealing'wax

Electrode 

~ j/32" by ^6 by 2"

Outside electrodes cut to

machine 

thread

1-foot lengths 

of solid rod added for weight

CROSS SECTIONS OF MINIATURE ELECTRODES.

A, Miniature electrodes used in Winter Garden area, Tex.: B, Miniature electrodes used in Kleberg 

County, Tex., and in Sarasota County, Fla.
U. S. GEOLOGICAL SURVEY

MILLI AMPERES 

24 26 28 30 32 34 36

MILLIAMPERES 

30 32 34 36 

500

DIAGRAMS SHOWING LOCATIONS OF SALT-WATER LEAKS IN WATER WELLS IN KLEBERG 

ELECTRODES AND MILLIAMMETER EQUIPMEN

A, Wen of B. Gfflespie, 3 miles southwest of KJngsvitte; B, Well of G. Nolan and others, 1 mile west of Kingsvill

METHODS OP LOCATING SALT-WATER LEAKS IN WELLS 15

leak apparently had filled the well below the leak, but in the lower part 

of the well, opposite the fresh-water sands, there had been some freshening as the result of mixture with fresh water.

Miniature electrodes

Winter Garden area. Tea:.- In order to explore wells without removing 

the pumps a pair of electrodes was made, small enough to be inserted into 

the well between the casing and pump column. The outfit used in the Winter Garden area (see pis. 7, A, and 8, A) includes a 15-inch length of 

3/8-inch copper tubing, at the upper end of which are two 1^-inch slots 

opposite each other. This tube is soldered to the outer strands of the 

cable and constitutes one electrode. The other electrode consists of a 

piece of no. 14 copper wire, which is fastened with sealing wax in the 

center of the tube directly opposite the slots and is attached to the insulated core of the cable. The cable has a breaking strength of 450 

pounds and consists of six strands, each of seven plow-steel wires 0.009 

inch in diameter, wound around a core of twelve B. & S. 36 gage enameled 

copper wires insulated with four winds of saturated cotton. The cable 

is wound on a small hand reel.

RESISTANCE IN OHMS MILUAMPERES 

100 200 300 400 0 25 50

. MILUAMPERES 

25 50

Figure 4. Diagrams showing the effect of varying the voltage 

on the resistance and conductivity of saline waters.

To determine the effect of different voltages on the relation between 

salinity and the resistance of the water a series of preliminary tests 

was made with this equipment. The electrodes were submerged in water of 

different salinities, different voltages were applied, and the indicated 

resistance was noted. The results of the tests are shown in figure 4.
16 CONTRIBUTIONS TO HYDROLOGY, 1937

These tests show that with a direct-current voltage of less than 3 volts 

the Wheatstone bridge is too sensitive in waters low in chloride, indicating resistances that are too great to measure with the apparatus. 

With more than 3 volts the bridge is less sensitive at all salinities, 

and as the voltage is increased the point at which an increase in salinity fails to register becomes lower. At low voltages, with the attendant 

low currents, gas bubbles that form on the negative electrode do not 

break away freely, and these bubbles increase the resistance. As the 

voltage is increased gas is formed more rapidly and the bubbles break 

away freely, and resistance from this cause is partly eliminated. However, 3 volts afforded satisfactory tests when the current was measured 

instead of the resistance, and this voltage was used in practically all 

the tests with the milliammeter and the miniature electrodes. The milliammeter (pi. 6, B) was less bulky than the Wheatstone bridge and gave 

just as satisfactory results.

Figure 5 shows the result of a test made with the miniature electrodes on the Pickna well after the pump had remained idle for 2 hours 

following the pumping test described on page 5. A shows the current indicated by the milliammeter for different positions of the electrodes in 

the well* B shows the resistance of the water to direct current as measured by the Wheatstone bridge. The resistance was practically constant 

from the water surface to a depth of about 212 feetj from 212 to 220 

feet it dropped rapidly; from 220 to 225 feet it remained constant; and 

below 225 feet it gradually increased, reaching the original amount at 

about 275 feet. It is evident from the graphs that during the 2 hours 

that the pump was idle salt water leaked into the well at a depth of 

about 220 feet, completely displacing the fresh water in the casing for 

a depth of about 5 feet and contaminating it down to a depth of about 

300 feet. Prom the amount of contamination during the period it was 

estimated that the well was receiving about 1 gallon a minute of highly 

mineralized water.

Kleberg County. Tex.- For the work in Kleberg County, Tex., a miniature apparatus was assembled that in some ways was an improvement over 

the one constructed for the Winter Garden area. In this outfit the 

metal spool is mounted upon a frame and is provided with commutator 

brushes so that the milliammeter can be kept in the circuit while the 

electrodes are being lowered into a well. The whole apparatus, exclusive of the wire, weighs less than 5 pounds. A view of the apparatus
METHODS OF LOCATING SALT-WATER LEAKS IN WELLS 17

is shown in plate 7, B. The electrodes are shown in plate 8, B. They 

consist essentially of a 3^-inch length of -J-inch brass welding rod that 

has been drilled through and threaded at each end to accommodate a no, 

10 machine screw with 32 threads to the inch. The side walls are cut 

through on opposite sides to form a slot about one-eighth of an inch 

wide for a. length of about 1^- inches. The lock screw is drilled longitudinally to allow the 0.09-inch cable to pass through and is split at 

the end so that it serves to pinch the cable and act as a clamp when 

screwed in beyond the limit of the female threads. The inner insulated 

core, or electrode, which is a tongue or plate of nickel alloy one 

thirty-second by three-sixteenths by 2 inches, is insulated from the rod 

at the top and bottom with sealing wax. With these electrodes the direction of the current makes very little difference, because by using a 

plate-center electrode instead of a round wire the two electrodes have 

more nearly the same area of effective surface exposed to the water.

CURRENT IN MILLIAMPERES RESISTANCE IN OHMS 

12 16 20 24 28 32 36 40 150 200 250 300 350 400 450

Z 100

2 200 

Estimated inflow of saltwater 

approximately I gallon per minute

300

400

Figure 5.--Diagrams showing the results of explorations with the 

miniature electrodes in the Pickna well. A, Conductivity indicated by the milliarameter; B, Resistance in ohms indicated by 

the Wheatstone bridge.

Results of three of the tests in which a milliammeter was used to 

measure the current are shown in plate 9. All the tests were made in 

wells that had been pumped nearly fresh a few minutes before the tests. 

These diagrams show that there were three leaks in two of the wells and 

one leak in the other. If the wells with more than one leak had stood
18 CONTRIBUTIONS TO HYDROLOGY, 1937

idle for aeveral daya before the teata were made only the top leak could 

have been located, becauae the wells would have been filled with aalt 

water from thia leak to the bottom.

Saraaota County. Fla,- The electrodea used during the inveatigation 

in Saraaota County, Fla., were similar to thoae uaed in Kleberg County.

Although the practicability of using the Wheatatone bridge with 

direct current waa demonatrated in the exploration of the wella in the 

Winter Garden area of Texaa, it waa decided that experimenta ahould be 

made with the alternating current especially to atudy the effect of polarization. A new apparatus waa aasembled that includea a bridge with a 

alide wire of a resiatance of 0 to 100 ohms, reaiatances capable of registering from 1 to 9,999 ohms, and a high-frequency hummer. In thia apparatua the hummer ia operated by four atandard dry cella and supplies 

alternating current of 1,000 cycles. The operation of the equipment is 

essentially the aame aa when the direct current is used, except that the 

circuit is balanced by adjusting the rheostat and slide wire until the 

minimum hum is obtained in a set of ear phones. This apparatus was used 

by Stringfield and Fiedler in Florida during 1932 and is illustrated in 

plates 5, B_, and 6, C_. Tests thus far have not shown that the alternating current has any special advantage over the direct current in the 

leakage explorations.

Additional characteristics

Much could be written about the effect of passing an electrical 

current through water containing a large amount of salt. The subject is 

discussed in most books on chemistry. It is known that counter currents 

are set up in the solution, but the effect of these currents upon the 

readings of the milliammeter or Wheatstone bridge is small, and it is 

believed they need not be taken into consideration when the electrodes 

are used under the conditions described in this report.

It is important to bear in mind when building the conductivity apparatus or making a teat of a well that complete insulation in the wiring system and the electrodes is absolutely necessary. If the insulation 

of the inner core of the cable breaks down, it is generally almost impossible to make satisfactory repairs in the field. The insulation must be 

water tight, otherwise the current will leak through to the outer 

grounded strands instead of following the route of greater resistance 

between the electrodes. Care must be taken to insure that the readings
METHODS OP LOCATING SALT-WATER LEAKS IN WELLS 19

obtained Indicate the salinity of the water at the electrodes rather than 

at a break In the Insulation of the cable many feet from the electrodes. 

In case a short circuit should occur in the apparatus the milliammeter is 

less likely to be damaged if a low voltage is being used.

Two ordinary flashlight batteries will furnish current for a dozen 

or more tests with the miniature apparatus. For tests with the large 

electrodes three batteries will give the best results. Time is saved and 

more reliable information obtained if the circuit is closed during the 

test and the apparatus is lowered slowly and steadily into the well. If 

pumping equipment is in place it is always advisable to pump the well 

enough to freshen the water; the casing may have more than one hole in 

it, and only the top hole can be located if the well has not been pumped.

Summary of results with the electrical-conductivity method

The equipment for detecting contamination by salt water was used in 

exploring 21 wells in the Winter Garden area of Texas. Of the 16 found 

to be salty, 10 showed salt water entering at depths ranging from 210 to 

250 feet below the ground surface; this is approximately the depth at 

which the well casing is usually reduced in size and seems to indicate 

that most of the salt water enters the wella where the casings overlap.

In KLeberg County, Tex., tests were made of 9 wells, of which 

several showed more than one leak.

In Sarasota County, Pla., tests were made of 12 flowing wells and 

1 nonflowing well. The tests with the electrical apparatus indicated 

that there was no appreciable difference in the concentration of mineral 

matter dissolved in the water at different depths. Analyses of water 

samples collected from these wells with the deep-well sampler substantiated the results.

CONSTRUCTION OP WELLS TO AVOID CONTAMINATION BY SALT WATER

Wells that penetrate formations containing salt water are likely to 

give trouble. The salt water may enter the well where the casing overlaps if the overlap has not been properly sealed or through holes in the 

casing produced by salt-water corrosion. Much of this trouble can be 

avoided by proper construction. The well should be cased with a good 

grade of genuine wrought iron, or cast iron. Reductions in the size of 

the casing should be as few as practicable. Where reductions cannot be
20 CONTRIBUTIONS TO HYDROLOGY, 1937

avoided swaged nipples are preferable to overlapping and the use of lead 

seals to close the annular space at the overlap. The casing should be as 

well protected as possible to resist corrosion. It is advisable to set 

the casing just above the fresh-water formation and concrete the lower 

half of the bottom length while the hole is full of mud, thus leaving a 

wall of mud on the outside to keep the salt water away from the casing. 

It is a good plan to paint the casing with asphaltic paint and wrap it 

with canvas or heavy paper to protect the asphalt from scratches while 

the string is being lowered into the well.

It costs much less to take extra precautions against salt water when 

the well is being drilled than it does to repair a well after it becomea 

contaminated with salt water. If only a cable-tool well-drilling rig is 

available a well that has become contaminated can be repaired by inserting a string of new casing on the inside of the old one. If a rotary 

drilling rig is available a new casing can be rotated around the old one, 

and the old one can then be removed from the hole. In some wells that 

are not likely to cave in it is possible to pull the old casing and insert a new one. New casing inserted inside of old casing cannot be expected to last more than a few years. If the defective casing is pulled 

a longer life can be expected of the new casing if special precautions 

are taken to leave a wall of mud on the outside to protect it.

The data thus far obtained in ELeberg County and in the Winter Oarden area appear to indicate that the salt water contamination ia not yet 

serious except, as it affects individual wells. But salt water is now 

entering the fresh-water formations through these defective wells and if 

allowed to continue may eventually cause serious general contamination. 

In order to avoid this result it is suggested that all old wells no 

longer in use be sealed from bottom to top. This can be done by cleaning out the well and pumping in neat cement or thick gritless clay, beginning at the bottom and continuing until the well is filled all the 

way to the surface. No attempt should be made to seal a well by simply 

shoveling dirt or debris in at the topj if this is done the filling 

material probably will bridge at some point above the bottom of the 

well, and although the well may appear to be sealed at the top, there 

will still be an open hole below, through which contamination can enter.
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