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UNITED STATES DEPARTMENT

GROUND WATER 

UNITED STATES, A

OF THE INTERIOR

IN THE 

SUMMARY

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 836-D

WATER RES88'.l«S BWSIOH 

REPORTS SSSTWII
UNITED STATES DEPARTMENT OF THE INTERIOR 

Harold L. Ickes, Secretary

GEOLOGICAL SURVEY 

W. C. Mendenhall, Director

Water-Supply Paper 836-D

GROUND WATER IN THE 

UNITED STATES

A SUMMARY OF GROUND-WATER CONDITIONS AND RESOURCES

UTILIZATION OF WATER FROM WELLS AND SPRINGS

METHODS OF SCIENTIFIC INVESTIGATION, AND

LITERATURE RELATING TO THE SUBJECT

BY

OSCAR EDWARD MEINZER

Contributions to the hydrology of the United States, 1938-39 

(Pages 157-229)

UNITED STATES

GOVERNMENT PRINTING OFFICE 

WASHINGTON : 1939

'or »al« by the Superintendent of Documents, Washington, D. C. ---- Price 15 cent!

CONTENTS

	Page 

.bstract _________________________________________________________ 157

itroduction-_----__-_-_--________________________.._______________ 161

Tater-bearing formations and their geographic distribution_____________ 164

East-Central region of Paleozoic and other old rocks ____-_--___-__ 164

Atlantic and Gulf Coastal Plain region.______ ___________________ 168

Great Plains region.____________________________________________ 170

Western Mountain region ______________________________________ 171

^ater-table conditions-____________________________________________ 174

rtesian conditions-_______________________________________________ 175

Artesian conditions in generaL__________________________________ 175

Paleozoic formations of East-Central region ______________________ 176

Roswell artesian basin____ ____________________________________ 177

Formations of Atlantic and Gulf Coastal Plain__-_______-_____---_ 178

Cretaceous formations of Great Plains region._______________ ____ 180

Glacial drift_________________________________________________ 183

Valley fill of Western Mountain region-__________ ________________ 184

ischarge of ground water through springs and by evaporation and transpiration_ _____________________________________________________ 186

Ground-water discharge in generaL ______________________________ 186

Large springs.________________________________________________ 187

Thermal springs.______________________________________________ 190

Ebbing and flowing springs.___________________________________ 192

tilization of ground water.________________________________________ 194

Public waterworks.____________________________________________ 194

Domestic supplies,____________________________________________ 196

Livestock supplies_____________________________________________ 198

Industrial supplies,__--__-___---_____-______-_-__-_________--_- 198

Irrigation supplies____-_-____-_-____-__-________________-__--__ 199

Uses for health and recreation________________________________ 201

ethods and results of ground-water investigations,___________________ 202

Systematic ground-water surveys ________________________________ 203

Intensive ground-water investigations______-__---__-__-_-______-_ 204

Quantitative problems___________________________ ________-_ 204

Molecular attraction.____-_-____-_________--____--_-___---_ 205

Recharge._--_------------_---_-------------------_---_--- 206

Discharge of ground water__________________________________ 207

Water table, capillary fringe, and piezometric surface_________ 207

Movement of ground water.________________________________ 208

Compression and expansion of aquifers_____-______--_____---- 210

Contamination by salt water________________________________ 211

Test wells._________________________________________ 211

Apparatus used in ground-water studies______________________ 211

Fluctuations of water levels.___________________________i____ 212

ork of the Geological Survey and cooperating agencies.______________ 220

terature relating to ground water_________________________________ 222

General summary of the literature.______________________________ 222

Sources of data for this paper.__________________________________ 222

List of representative publications_______________________________ 223

>pendix_______________________________________________________ 229

lex__________________________________________________________ 231

in
IV CONTENT'S

ILLUSTRATION^

FIGURE 11. Map of the United States showing mes 

12. Map of the United States showing th 

the United States with respect to 

subdivision into ground-water proi, 

13. Map of the United States showing a

i'fi annual precipitation _ 

1} four major regions of 

ground water and their 

rtnces

tjeas in which Paleozoic

l

14. Map of the eastern and central partb of the United States 

showing areas in which Pre-Cambrian rocks are at or near 

the surface

15. Map of the eastern part of the United 

which Triassic rocks are at or near 

16. Map of the United States showing p 

by glacial drift

States showing areas in 

t[he surface

ifincipal areas underlain

17. Map of the western part of the United iptates showing principal 

areas underlain by valley fill

18. Map of the western part of the Unitec 

which Tertiary or Quaternary volca 

the surface

19. Ideal section illustrating chief requisil 

flows

20. Generalized section of the Roswell an 

21. Map of the Winter Garden district 

Texas, showing original artesian co 

as affected by heavy withdrawals 

22. Section along the line A- A' in figure 

23. Generalized section of the Dakota art 

24. Map of the lower peninsula of Michiga 

sian flow, supplied chiefly from glac 

25. Perspective view and section of a typi

26. Map of the northern drainage basin 

Nevada, showing intake and dischai 

27. Map of the United States showing sp 

tude _ _ _

28. Map of the United States showing the 

29. Hydrographs, for selected days, of 

springs near Broadway, Virginia, an 

30. Map showing States in which most of 1 

are derived from wells __

31. Graphs of water levels in wells showin 

precipitation and seasonal variatic 

transpiration

32. Graphs of water levels in wells show:

33. Graphs of water level in a well show 

water by transpiration of willows.

34. Graphs of water levels in two observe 

tuations naused hv mimnine a third

States showing areas in 

nic rocks are at or near

5 conditions for artesian

jsian basin _

)f the Coastal Plain in 

aditions and conditions

:l

;sian basin

n showing areas of arteial drift______________

;al western valley showof Big Smoky Valley, 

ge of ground water __ _ 

 ings of the first magnirmal springs _ _ _ __

tie ebbing and flowing

le public water supplies

1 fluctuations caused by 

ns in evaporation and

ng discharge of ground

ng discharge of ground

tion wells showing fluewell _ _ _ _ _

Pag< 

15- 

161

16J 

16J

16( 

16' 

16!

17:

17:

17> 

17

17

18 

18

18 

18 

18

18 

19

19 

19

21 

21 

21 

21
CONTENTS v

Page 

FIGURE 35. Graph of water level in a well showing fluctuations caused by

pumping and by passing railroad trains._-__--___-_______ 216

36. Graphs of water levels in a well showing the effects of passing

railroad trains^________________________.._-___--__-____ 216

37. Graph of water level in a well showing fluctuations caused by

variations in atmospheric pressure._____________________ 217

38. Graph of water level in an artesian well 100 feet from the shore

showing fluctuations caused by the ocean tide.___________ 218

39. Graph of water level in a well 800 feet deep showing fluctuations caused by the ocean tide___________-__-__-_-_-____ 218

40. Graph of water level in a well showing fluctuations caused by

an earth tide_________________________________________ 219

41. Graphs of water levels in wells showing fluctuations caused by

earthquakes._________________________________________ 220

WATER-SUPPLY PAPER 836 PLATE 15

RELIEF MAP OF THE UNITED STATES

GROUND WATER IN THE UNITED STATES A SUMMARY

By OSCAR EDWARD MEINZER

ABSTRACT

Water-bearing formations and their geographic distribution. -The United States 

an be divided into four regions with respect to ground water, that is, the water 

hat supplies the springs and wells (1) the East-Central old-rock region, (2) the 

.tlantic and Gulf Coastal Plain region, (3) the Great Plains region, and (4) the 

Western Mountain region.

The East-Central region includes about one-third of the area and two-thirds 

f the population of the country. Most of the region is underlain by Paleozoic 

)cks, including water-bearing sandstones and limestones and unproductive shales; 

le deep water from these rocks is highly mineralized. Parts of this region are 

nderlain by Pre-Cambrian or Triassic rocks that yield small supplies. The glacial 

rift, in the northern part, and the glacial outwash sands and gravels beyond the 

rift border yield numerous large water supplies.

The wide and well populated coastal plain bordering the Atlantic Ocean and

ulf of Mexico is underlain by Cretaceous, Tertiary, and Pleistocene formations,

eluding many beds of sand and limestone that yield numerous supplies of water, 

.any of which are large.

The semiarid or subhumid plains region lying east of the Rocky Mountains conins extensive Tertiary and Pleistocene deposits of water-bearing sand and gravel 

id Cretaceous sands that yield highly mineralized artesian water, especially in

orth Dakota and South Dakota; also water-bearing glacial drift in the north and

 oductive Permian limestone in the Roswell artesian basin in New Mexico. In 

.e areas of Cretaceous shale the water supplies are scarce.

The Western Mountain region, which occupies about one-third of the area 

the country, is chiefly arid and contains extensive tracts in which water supies are scarce. Its principal water-bearing beds are the sand and gravel in 

e Pleistocene or Tertiary valley fill, which in some parts, especially in Calirnia, yield very large supplies. In some places in the Northwest the Tertiary

 Icanic rocks yield much water to springs and wells.

Water-table conditions. The water supplies of the springs and wells in the 

lited States are largely derived from formations that have essentially waterble conditions. These are the surficial deposits of sand and gravel; the sand- 

)nes and limestones in their outcrop areas; the extrusive volcanic rocks of the 

arthwest; and the dense igneous and metamorphic rocks and clays and shales, 

lich are commonly rendered somewhat permeable by weathering near the 

rface. As these formations are extensively exposed at the surface, their supes are readily replenished by the water from rain and snow. The largest 

pplies of water come from the deposits of sand and gravel, and these may 

grouped as follows: (1) Glacial outwash from the continental ice sheets occur- 

.g from the Atlantic to the Pacific, (2) Valley fill in the Western Mountain 

'ion (in part artesian), (3) Tertiary and Quaternary deposits in the Great 

lins region, and (4) Tertiary and Quaternary terrace and lowland deposits 

the Atlantic and Gulf Coastal Plain.

157
158 CONTRIBUTIONS TO HYDROLOGY, 1938-39

Artesian conditions. The principal artesian systems in the United States ar< 

as follows: (1) the extensive Paleozoic artesian system occupying a large part o 

the East-Central region, in which the shales confine water under artesian pressur 

in the sandstones and limestones; (2) the small but productive Roswell artesia] 

basin, in New Mexico, in which cavernous Permian limestone is the artesian for 

mation; (3) the artesian system formed by the entire Atlantic and Gulf Coasts 

Plain, in which Cretaceous and Tertiary strata dip toward the sea, and th 

water in the sands and limestones is held under artesian pressure by the interbedde' 

shales; (4) the Cretaceous artesian system of the northern and central parts c 

the Great Plains region, in wljich water is confined in the sandstones, under grea 

artesian pressure, by the thick, dense, overlying shales; (5) numerous small an> 

imperfect artesian systems in the glacial drift; and (6) numerous artesian system 

in the valley fill of the Western Mountain region, the largest of which are in th 

San Joaquin Valley, in California, and the San Luis Valley, in Colorado.

In most areas of artesian flow the pressure has greatly diminished, and larg 

supplies are generally obtained by pumping.

Discharge of ground water through springs and by evaporation and transpiration.- 

In the relatively humid eastern part of the United States, the streams are generall 

fed by numerous branches that receive effluent seepage at many points, excef 

in the limestone terranes, in which the springs are larger but less numerous. I 

the arid and semiarid western parts of the country, the recharge and hence also tl 

discharge of ground water are reduced in even greater proportion than the precip 

tation, as compared with the humid East, and the discharge is largely by transpirs 

tion of the plants known as phreatophytes.

According to available data, there are in the United States 65 springs of tl 

first magnitude, that is, springs yielding more than 100 second-feet. Of these, J 

rise in volcanic rock or associated gravel in the Northwest; 24 rise in limeston 

chiefly in Florida, Missouri, and Texas; and 3 rise in sandstone in Montan 

Silver Spring, Florida, which is the largest limestone spring in the country, has s 

average discharge of 808 second-feet. The springs that issue from volcanic roc 

and associated gravel along a 50-mile stretch of Snake River, Idaho, have an aggr 

gate discharge that averages 5,085 second-feet.

In a recently published report (Water-Supply Paper 679-B) are listed 1,0. 

thermal springs or spring localities, all of which are in the Western Mounta 

region except 52 in the East-Central region, and 3 in the Great Plains regie 

(Black Hills). Yellowstone National Park exceeds all other areas in the abu 

dance of springs of high temperature. Nearly two-thirds of the thermal sprin 

issue from igneous rock, chiefly intrusive magmas, deriving their heat large 

from magmatic sources and their water largely from surface sources. Those 

the eastern part of the country are largely due to artesian structure.

There are in the United States 23 known periodic or ebbing and flowing spring 

of which 9 are in Virginia and 4 in Missouri. All or nearly all are in limestone.

Utilization of ground water. About 10,000 communities, with about 75,000,0 

inhabitants (1930 census), have public waterworks, of which about 6,500 coi 

munities, with about 20,000,000 inhabitants, are supplied with ground wai 

from wells. The total yielded by wells for public supplies is estimated at 2,001 

000,000 gallons a day.

One of the greatest achievements in American history has been the develc 

ment of water supplies of good quality for domestic use, that is, for drinkii 

cooking, and laundry and toilet purposes. A very large proportion of the 75,00' 

000 people in communities served by public waterworks have ample and perenn 

supplies of safe water delivered under pressure. About 47,000,000 people livi 

in several thousand small communities and on about 6,500,000 farms have priv£ 

water supplies, chiefly from wells, supplemented in hard-water areas with ra:
GROUND WATER IN THE UNITED STATES 159

pater cisterns for toilet and laundry uses. Much progress has been made in 

mprovement of supplies from private wells but much remains to be done, largely

 hrough advances in well drilling practices.

Water supplies for livestock are partly the same as the domestic supplies but 

nany additional supplies have been developed to make it possible for the live- 

,tock to utilize all the available forage. This has been done chiefly by sinking 

veils but also by improving springs and building small reservoirs.

Numerous large and small private water supplies have been developed from 

veils for industries and institutions in areas not reached by public waterworks 

ind also to a considerable extent in the large cities.

Over 2,100,000 acres was irrigated in 1929 with water from wells, about two-

-hirds of which was in California. Only 2 or 3 percent of this acreage was irrigated with water from flowing wells, the rest from pumped wells. The area 

rrigated with water from wells is about 11 percent of the total irrigated area, 

iut the value of the product is proportionately greater because it consists largely 

)f fruits and vegetables. About twice as much water from wells is used annually 

'or irrigation as for public supplies.

In the United States there are some well-equipped health resorts at watering 

places and many that are only modestly or poorly equipped. A total of 184 

;hermal springs are reported to be used for resorts, including sanitariums. In 

L923 about 45,000,000 gallons of natural waters were sold, from 433 commercial 

springs, for table and medicinal uses. The American people rank high in the 

personal use of water, both external and internal. From a broad viewpoint, they 

ioubtless rank higher than is generally assumed in its therapeutic use.

Methods and results of ground-water investigations. The ground-water investigations have been of two principal kinds (1) systematic areal surveys and (2) 

special investigations, which are generally more intensive and contribute to a 

Tiore detailed knowledge of hydrologic principles. It has not been possible to 

;arry out a uniform ground-water survey of the entire country, but more or less 

standardized methods are applied as opportunity is afforded.

The intensive studies have related largely to the quantities of ground water 

;hat can be obtained from underground storage and from recharge. Quantitative 

nethods are grouped as intake, discharge, storage, and transmission methods. 

Water-bearing formations are studied with respect to their functions as reservoirs 

ind as conduits.

Studies have been made of the infiltration of rain and stream water, the retention of the water in the root zone, and its transmission to the water table; the 

rate of discharge of ground water by springs, effluent seepage, evaporation, and 

transpiration from phreatophytes; specific yield, or changes in storage correspondng to changes in the level of the water table; permeability and the laws of groundvvater flow; and changes in storage in confined formations due to their elasticity. 

Studies have been made of the balance between fresh ground water and the 

neavier salty water; deep wells have been explored with current meters and 

salinity apparatus to determine inflow and outflow of fresh and salty water; and 

geophysical methods, especially the electric resistivity method, have been studied 

as to their availability for locating salty water and permeable water-bearing beds.

The principal instruments of precision in ground-water investigations have 

?ome to be the automatic water-stage recorders, of which several hundred are 

installed over wells 200 by the Geological Survey and cooperating parties. A 

nation-wide program including several thousand observation wells has been 

developed, and a report is published annually giving water levels or artesian 

pressures in these wells. Emphasis has also been placed on obtaining corresponding records of pumpage and artesian flow. 

138108° 39 2
160 CONTRIBUTIONS TO HYDROLOGY, 1938-39

In 1917 the Geological Survey reestablished its laboratory for making chemica 

analyses of water. In 1923 it established a hydrologic laboratory, in whici 

natural rock materials are tested for mechanical composition, permeability 

porosity, and moisture equivalent the last two as a means of computing specific 

retention and specific yield. Similar work is done in various other laboratories 

in the country.

Work of the Geological Survey and cooperating agencies. Ground-water investigations were actively conducted near the close of the past century and in the earl} 

years of this century. Then there was a notable curtailment. In the pasl 

twenty years there has been progressive and large increase in the funds made 

available for ground-water investigations and a corresponding improvement in 

the quality of the technical work done. The demand came first from the States, 

many of which supplied funds for cooperation with the Ground Water Division 

of the Geological Survey. Later these funds were met by increased Federal 

appropriations. In the fiscal year 1939 about $380,000 was expended for groundwater investigations by the Geological Survey and cooperating State, Territorial, 

county, and municipal organizations.

Literature relating to ground water. The Geological Survey has published 

about 700 papers that contain information on ground water, of which about 

400 relate primarily to this subject. The technical literature relating to ground 

water published by other investigators is extensive and widely scattered. In 

the fiscal year 1938 the Geological Survey and cooperating agencies released 

about 100 papers relating to ground water, of which 9 were published by the 

Geological Survey, the rest being published by cooperating agencies or in scientific journals or released in mimeographed or typewritten form.
INTRODUCTION

The 48 States that constitute the United States of America cover 

an area of a little more than 3,000,000 square miles. (See pi. 15.) 

This vast area comprises a geologic section of great aggregate thick161
^ i_

East-central region of Paleozoic and other old 

Atlantic and Gulf Coastal Plain region 

Great Plains region 

Western mountain region

FIGURE 12. Map of the United States showing the four major regions with respect to ground water 

(After Geol. Survey Water-Supply Paper 489, pi. 31, with some revision of provinces in th
EXPLANATION

EAST-CENTBAL BEQION OF PALEOZOIC AND OTHER OLD BOCKS

Province C is underlain by igneous and metamorphic rocks (chiefly pre-Cambrian) 

and Triassic sandstone. These rocks yield many small supplies of good water. 

Province D is mountainous and is underlain by folded and faulted Paleozoic strata, 

pre-Cambrian metamorphic rocks, and associated igneous rocks. These rocks supply 

water of good quality to numerous springs, spring-fed streams, and shallow wells. 

In province B the bed rocks (chiefly metamorphic) are overlain by glacial drift. The 

bed rock and boulder clay yield many small supplies of good water, and glacial sand 

and gravel yield large supplies in some places.

Provinces E, F, and Q are underlain by Paleozoic rocks. The sandstones and 

limestones yield good water to shallow wells, but deep wells strike mineralized water, 

much of which is unfit for use. The shales yield meager supplies. The glacial drift 

in province F yields many supplies, both large and small. The outwash sand and 

gravel in valleys in province Q and the northern part of province E yield large 

supplies.

In province H glacial drift yields many water supplies, but where the drift is thin 

only meager supplies are obtained from the underlying granite or other pre-Cambrian 

rocks. The water ranges in quality from soft and good in the eastern part of the 

province to highly mineralized and even unfit for use in the western part.

ATLANTIC AND GULF COASTAL PLAIN REGION

In province A Cretaceous, Tertiary, and younger strata of sand and limestone 

yield many small and many large water supplies. Much of the water is of good 

quality, but some is salty.

OKEAT PLAINS REGION

Provinces I, J, K, N, O, and Q are in general underlain by Cretaceous formations 

chiefly unproductive shale with interbedded or underlying sandstone that yields

highly mineralized 

ince I. In large are

Hills, thick Cretace

only meager supplie

N the Cretaceous st

late Cretaceous age

small to moderate su

supplies of hard bu

In provinces K an

supplies of somewh

lying Cretaceous for

"Red Beds" in prov

not of much value, a

In the Roswell art

plies of hard but usa

province generally y

alluvial sand and gr

In the Rocky Mo

province U), water 

In province Q more 

dissected plateaus w

lava beds and assoc

yield large supplies 

and gravel in the br

of generally good wa

inces water supplies 

formations.
164 CONTRIBUTIONS TO HYDROLOGY, 1938-39

ness, including rocks of almost every kind that range in age from 

pre-Cambrian to Recent. It also has great diversity in geologic 

structure, altitude and form of land surface, and climatic conditions.

In the eastern part of the United States the mean annual precipitation ranges from less than 40 to more than 60 inches. (See 

fig. 11.) In general the precipitation decreases toward the west, and 

in most parts of the Great Plains the annual mean is between 15 and 30 

inches. In the extensive Western Mountain region the climate is 

generally arid, but the range in mean annual precipitation is from more 

than 100 inches in a few localities in the extreme Northwest to less 

than 5 inches in parts of southwestern Arizona and southeastern 

California.

The great diversity in geology, topography, and climate has resulted 

in a corresponding great diversity of conditions with respect to the 

ground water, that is, the water in the zone of saturation, which supplies the springs and wells. Thus there is great variety in the intake, 

quantity, movement, artesian pressure, chemical character, and mode 

of discharge of the ground water.

In the present paper the effort is made to give a brief but comprehensive summary of the complex ground water conditions in the United 

States (not including the outlying territories), and of the utilization 

of the ground water, its value as a natural resource, and the scientific 

investigation that has been and is at present being made of this subject.

In previous studies the United States has been divided into groundwater provinces. For the purpose of this paper these provinces are 

grouped into four major regions. (See fig. 12.)

As this paper covers a comprehensive field it is necessarily based on 

the work of many scientists. Some of the data have not heretofore 

been published. Much of the information is taken directly from the 

author's previously published papers on ground water, but those were 

to a considerable extent based on publications by others. The list of 

publications on pages 223-229 includes the principal works used in the 

preparation of this paper and also other representative publications 

relating to the different subdivisions of the subject. In the text these 

publications are cited by their serial numbers as given in the list. 

Some of the publications contain bibliographies or numerous references 

to other published works.

WATER-BEARING FORMATIONS AND THEIR 

GEOGRAPHIC DISTRIBUTION

EAST-CENTRAL REGION OF PALEOZOIC AND OTHER OLD ROCKS

The eastern and central parts of the United States consist chiefly 

of old rocks, underlain in the northern part by glacial drift. The old 

rocks are chiefly of Paleozoic age but include large areas of pre-Cam-
GROUND WATER IN THE UNITED STATES 165

brian rocks, which are older than Paleozoic, and a few relatively small 

areas of Triassic rocks, which are younger than Paleozoic. (See figs.

g § "s a

13, 14, and 15.) This region covers about one-third of the entire 

area of the country and contains fully two-thirds of the inhabitants.
166 CONTRIBUTIONS TO HYDROLOGY, 1938-39

All the Paleozoic rock systems are represented, from the Cambrian 

to the Permian (which is regarded by the Geological Survey as a part 

of the Carboniferous system). Together they form a succession of 

sedimentary strata, chiefly shale, sandstone, and limestone, having an 

aggregate thickness of many thousand feet. Over most of the region 

the rock strata lie nearly horizontal, but in the Appalachian Mountains

FIGURE 14. Map of the eastern and central parts of the United States showing areas in which pre-Oambrian 

rocks or post-Cambrian intrusive or plutonic rocks are at or near the surface. These rocks yield small 

supplies of water to springs, to dug wells that end in the disintegrated surficial parts of the rocks, and to 

drilled wells that encounter water-bearing joints within a few hundred feet of the surface.

and in a few other places they are folded and faulted. From the 

many different formations of Paleozoic sandstone and limestone are 

obtained a great number of water supplies, both large and small, for 

domestic, livestock, municipal, and industrial uses. In most of the 

region the potable water comes from depths of not more than a few 

hundred feet, and the deeper water is salty. In some parts, however, 

especially in Wisconsin, Minnesota, Illinois, Iowa, and Missouri, the
GROUND WATER IN THE UNITED STATES 167

deeper water is potable, though highly mineralized, and furnishes large 

public and industrial supplies. The shales, which are especially 

abundant in the Pennsylvania!! and Permian series of the Carboniferous system, are generally unproductive or yield only small supplies.

200 Mites

200 Kilometers

FIGURE 15. Map of the eastern part of the United States showing areas in which Triassic rocks are at or 

near the surface. These rocks consist chiefly of red sandstone and other sedimentary beds that yield water 

in moderate quantities. They include some igneous rocks, commonly called trap, that are not productive 

of water.

Where they occur at the surface and the deeper water is salty, the 

problems of obtaining a satisfactory water supply are difficult.

Parts of the East-Central region are underlain by pre-Cambrian 

rocks, chiefly granite, gneiss, and schist, or by later intrusive or plutonic rocks. Such rocks occur at or near the surface in northern and 

western Minnesota, northern Wisconsin, and the northern peninsula 

of Michigan, in the Blue Ridge and the Piedmont Plateau from Ala138108° 39 3
168 CONTRIBUTIONS TO HYDROLOGY, 1938-39

bama to New York, in the Adirondack Mountains of northeastern 

New York, and in New England. (See fig. 14.) Water supplies 

for domestic and stock use and for some small industries and public 

waterworks are obtained from the weathered and jointed parts oi 

these rocks near the surface, and exceptionally at depths of several 

hundred feet, but in some places these rocks fail to yield even small 

supplies of water.

In the Piedmont Plateau and in New England there are several 

belts of Triassic rock, consisting largely of red sandstone that yields 

moderate supplies of water. (See fig. 15.)

Glacial drift of several successive ice sheets overlies the older rocks 

in the northern part of this region to depths ranging from a few feet 

to a few hundred feet. (See fig. 16.) The drift consists largely of 

boulder clay but includes many irregular beds of sand and gravel that 

underlie the boulder clay or are interbedded with it. The boulder 

clay yields small supplies of water to many shallow dug wells, whereas 

the sand and gravel yield abundant and permanent supplies to an 

ever-increasing number of deeper drilled wells for domestic, livestock, 

and industrial uses and for municipal waterworks.

Great quantities of sand and gravel were deposited in the valleys of 

streams that headed in the glacial ice. In the drainage basin of the 

Mississippi River the sand and gravel deposits extend down the northern tributaries, including the Ohio and the Missouri, and down the 

valley of the trunk stream far beyond the mouth of the Ohio. These 

deposits contain large quantities of water, which they yield freely to 

wells, and their storage is readily replenished by infiltration from the 

surface. They furnish many large water supplies for cities and 

industries.

ATLANTIC AND GULF COASTAL PLAIN REGION

A wide coastal plain, occupying fully one-seventh of the entire area 

of the United States, borders the Atlantic Ocean and the Gulf of 

Mexico. It extends from Martha's Vineyard, in Massachusetts, to 

the Rio Grande, and thence into Mexico. It includes the peninsula 

of Florida and extends up the Mississippi Valley to the mouth of the 

Ohio River. (See fig. 12.) .

This region is well populated and teems with human activities of 

many kinds. It is underlain by Cretaceous, Tertiary, and Pleistocene 

sedimentary formations which include numerous beds of water-bearing 

sand with some gravel, and in parts of the region, especially Florida 

and Texas, beds of cavernous water-bearing limestone. In this region 

ground water is especially important in furnishing supplies not only 

for domestic and stock use but also for a large proportion of the industrial establishments and municipalities, including most of the large 

cities, and for irrigation, especially of vegetables and fruits in Texas 

and Florida and of rice in Texas, Louisiana, and Arkansas.
GO P

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£. P P i CfQ PFIGOBE 16. Map of the United States showing principal areas underlain by glacial drift. (A

the Wisconsin or latest drift sheets; light shading indicates older drift. Many small pat

not shown on this map. Outwash deposits and deposits of loess beyond the drift sheets 

gravel, constitutes one of the most important sources of water supply in the United State
170 CONTRIBUTIONS TO HYDROLOGY, 1938-39

municipal and industrial uses. The very broad Mississippi Valle; 

from the mouth of the Ohio to the mouth of the Mississippi, con 

tains extensive Pleistocene deposits of sand and gravel, mostly o 

glacial outwash origin, that yield very large supplies, used especially 

for the irrigation of rice.

GREAT PLAINS REGION

In an extensive semiarid or subhumid agricultural region east o 

the Rocky Mountains, about 500 miles wide in the northern par 

and tap.ering toward the south, the Paleozoic and older rocks ar 

generally overlain by younger formations, including rocks of Triassic 

Jurassic, Cretaceous, Tertiary, and Pleistocene age. This regioi 

corresponds in general but not exactly to the region that is commonly 

called the Great Plains. (See fig. 12.)

Nearly all of the northern and central parts of this region ar 

underlain by Cretaceous formations (chiefly Upper Cretaceous) 

consisting mostly of impermeable shale but with water-bearing 

sandstones interbedded with them or occurring at or near the base 

The water in the Cretaceous sandstones is generally under artesiai 

pressure and supplies many flowing wells, especially in North Dakots 

and South Dakota. It is generally highly mineralized, and mucl 

of it is unfit for ordinary use.

In the northwestern part of the region, chiefly in western Nortl 

Dakota, eastern Montana, and eastern Wyoming, there are thicl 

sedimentary deposits of early Tertiary and perhaps in part lat< 

Cretaceous age, which include many irregular beds of sandstone tha 

yield potable water, generally in small quantities. Some wate 

supplies are also obtained from coal beds.

In most of the central and southern parts of the region the Cre 

taceous and older rocks are overlain by late Tertiary and Pleistocen 

deposits that consist largely of alluvial outwash from the Rock; 

Mountains. The beds of sand and gravel in these deposits generally 

furnish ample supplies of water of good quality for domestic, stock 

municipal, and industrial uses, and locally for irrigation. Th 

Pleistocene deposits contain much coarse and well-assorted materia 

that yields water very freely. They extend down the valleys of th 

principal streams and merge to some extent with the outwash fron 

the continental ice sheets, covering extensive areas in the centra 

parts of Nebraska and Kansas.

The northeastern and extreme northern parts of this region ar 

overlain by glacial drift, which furnishes potable water to many well 

for domestic, stock, municipal, and industrial uses. (See fig. 16.)

In parts of the Great Plains region, especially where the Cretaceou 

shale is at the surface and the water of underlying sandstones i 

salty, supplies of potable ground water are lacking or very meage
GROUND WATER IK" THE UNITED STATES 171

id recourse must be had to the generally unsatisfactory and uncertain 

ipplies obtained by storing rain water or run-off. In the northern 

art of the valley of the Red, River of the North, also, the ground 

ater is generally salty.

Over a considerable area on the east side of the mountains in New 

[exico and Texas, Paleozoic rocks are at the surface, and in the 

oswell basin cavernous Permian limestone yields large supplies of

 tesian water for irrigation.

WESTERN MOUNTAIN REGION

The Western Mountain region, which occupies about one-third 

: the entire area of the United States (see fig. 12), has many diverse 

mditions. Although generally arid, it experiences the country's 

ttremes of humidity and aridity; although generally sparsely popu- 

,ted, it contains a number of large cities and great developments of 

dning, stock raising, agriculture, and horticulture; although generally 

eking in water supply, it has some of the largest rivers and springs 

id some of the most copious of water supplies developed from wells. 

i different parts of the region water is obtained from many differem 

irmations and under many different conditions.

In the Rocky Mountains, which occupy the eastern part of the

 gion, and in other areas of large and rugged mountains, the water 

ipplies are obtained chiefly from springs and from streams fed by 

>rings and melted snow.

The High Plateau, in eastern and southern Utah, northern Arizona, 

mthwestem Colorado, and northwestern New Mexico, is underlain 

V a great succession of more or less flat-lying sedimentary strata, 

icluding rocks of Carboniferous, Triassic, Jurassic, Cretaceous, and 

ertiary age. These rocks are deeply cut by the Grand Canyon of 

le Colorado River and the canyons of the tributary streams. Water 

ipplies are obtained from many of these rocks, locally in abundance, 

at in general ground water is scarce, and much of the available water

highly mineralized. Large parts of the plateau area are virtually 

ithout water supplies. Farther north, especially in western Wyoing, there are extensive areas of Cretaceous and Tertiary strata 

ith variable ground-water conditions.

Much of the Western Mountain region, especially in southern and 

>ntral California, Nevada, western Utah, southern Arizona, and 

rge parts of New Mexico, is characterized by isolated mountain 

mges and broad intervening valleys that contain thick deposits of

 avel, sand, and clay derived by erosion of the mountains. (See 

y. 17.) The upper part of this valley fill is generally of Quaternary 

?e, but the deeper fill is largely Tertiary. The irregular beds of 

md and gravel receive water from the mountain streams, and they 

iiierally yield abundant supplies of potable water for domestic,

 ock, municipal, and industrial uses and for desert watering places.
172 CONTRIBUTIONS TO HYDROLOGY, 1938-39

They furnish very large supplies for irrigation in some places, esp< 

cially in California and Arizona. If the water pumped for irrigatio 

is included, the valley fill of this region furnishes more water to wel 

than any other group of formations in the United States.

FIGURE 17. Map of the western part of the United States showing the principal areas underlain by vall( 

fill. This fill includes much sand and gravel that yield water freely and in large quantities. It co 

stitutes the most valuable group of aquifers in the Western Mountain region.

Gravel and other materials were washed out from the abundar 

mountain glaciers during the glacial stages of the Pleistocene an 

were in part deposited in the lakes that occupied many of the val lej 

during the same stages. Locally the outwash and shore gravej 

yield much water. In the extreme northern part of the region thei
GROUND WATER IN THE UNITED STATES 173

' great deposits of coarse glacial outwash that yield very large 

uplies of water.

Extrusive volcanic rocks of Tertiary and Quaternary age, largely 

salt, are abundant and widely distributed throughout the Western

UEE 18. Map of the western part of the United States showing areas in which Tertiary or Quaternary 

jlcanic rocks are at or near the surface. The extensive lava beds, especially in Idaho, Washington, 

regon, and northern California consist chiefly of basalt; they yield abundant supplies to many drilled 

ells and give rise to numerous springs, some of which are very large. No Tertiary or Quaternary 

slcanic rocks are exposed in the eastern part of the United States.

ountain region, especially in Idaho, Washington, Oregon, and northi California. (See fig. 18.) These rocks are in part dense and 

productive, but in part they take in the water from rain and snow
174 CONTRIBUTIONS TO HYDROLOGY, 1938-39

freely and discharge it through huge springs or through wells of larg 

capacity. The areas of volcanic rock are in most places only sparse! 

inhabited, and there is only moderate development of the large suj 

plies of good water that are available from these rocks. This is i 

contrast to the Hawaiian Islands, where very large developments hav 

been made from rocks of this kind.

WATER-TABLE CONDITIONS

Below a certain level the permeable rocks are generally saturate* 

with water under hydrostatic pressure and are said to be in the zone o 

saturation. The upper surface of the zone of saturation, where i 

occurs in permeable materials, is called the water table (1, 40). 1 A 

greater depths water-bearing formations may lie below relativel; 

impermeable confining beds and may consequently be under artesia; 

conditions. In nearly all parts of the United States a water tabl 

occurs at greater or less depth below the land surface. Even th 

compact igneous and metamorphic rocks and the dense clay and shal 

formations have in most places become sufficiently permeable b; 

weathering near the surface to have a water table.

The water supplies of the springs and wells in the United State 

are largely derived from formations in which the water is essentiall; 

under water-table conditions. Nearly all the productive water 

bearing formations occur at or near the surface over more or less ex 

tensive outcrop areas not only the surficial deposits of sand and grave 

and the extrusive volcanic rocks (47), but also the older water-bearinj 

formations. Thus in many parts of the country large areas an 

underlain at or near the surface by weathered limestones or b; 

sandstones that yield ample and perennial supplies of water to man;1 

relatively shallow pumped wells (6, 8, 13, 14, 21, 60, 61, 64). L 

other large areas the surface formations consist of relatively imper 

meable rocks, such as the compact igneous and metamorphic rocks 

the clay and shale formations, and the boulder clay of the glacia 

drift. In these areas there are many shallow pumped wells whicl 

yield supplies that are relatively small but very valuable, especially 

where 110 deeper water-bearing formations occur or where the deepe 

water is too highly mineralized for use. Some of these shallow well: 

yield perennial supplies, whereas others fail in dry seasons througl 

the decline of the water table or the virtual disappearance of th< 

meager supply of ground water (8, 32, 43, 57, 61).

Among the most productive of the formations that yield wate: 

essentially under water-table conditions are the great surficial deposits 

of sand and gravel, as follows:

1. Extensive deposits of sand and gravel washed out from th( 

fronts of continental ice sheets, which furnish large perennial supplies

1 Numbers iu parentheses refer to publications listed on pages 223-229.
GROUND WATER IN THE UNITED STATES 175

> a great number of municipalities, institutions, and industrial 

itablishments all the way from the Atlantic Ocean to the Pacific 

., 8, 21, 25, 43, 56, 57, 60, 89, 97).

2. Valley fill of the Western Mountain region, which, in many 

irts of the region, furnishes large supplies for municipalities, indusles, and irrigation, to some extent under artesian conditions (1, 15,

3. 22, 38, 58, 59, 65, 69, 75, 83, 90).

3. Tertiary and associated Quaternary deposits of sand and gravel 

i the Great Plains region, which furnish almost the entire water 

ipply for large parts of the region (1, 37).

4. Late Tertiary and Quaternary terrace and lowland deposits of 

le Atlantic and Gulf Coastal Plain, which largely mantle the older 

trmations, yielding moderate supplies to many pumped wells throughit the region and large supplies in some areas (1, 26, 28, 78).

As the formations that have water-table conditions generally lie at 

le surface over all or large parts of their extent, their intake facilities 

:e generally good, with the result that their supplies are readily 

splenished by the water from rain and snow or from influent streams.

ARTESIAN CONDITIONS

ARTESIAN CONDITIONS IN GENERAL

The height to which the ground water will rise in wells varies not 

ily from place to place but also, in nearly every locality, with the 

3pth of the water-bearing bed below the water table. These almost 

liversal variations in the head of the ground water are the result 

' the complexity in the stratigraphy and structure of the rocks, the 

ilief of the land, and the sources of intake. Where the head decreases 

ith depth the upper ground water tends to move downward to the 

?eper water-bearing beds, except as there are intervening beds 

iat are entirely impermeable arid continuous; where the head in-

 eases with depth the deeper water is under pressure transmitted 

om some more or less distant intake area at a higher altitude, and this

 tesian pressure tends to cause upward leakage unless the confining 

id is entirely impermeable and continuous. Thus imperfect artesian 

ructure is of very common occurrence and produces flowing wells 

ith slight head in many low places (7, 18). In areas in which the 

ater-bearing beds are overlain by extensive and effective confining 

?ds and have their intake areas at sufficiently liigh altitudes, large

 eas of artesian flow with considerable artesian pressure may result 

!). In figure 19 is given an ideal section which illustrates very simply 

le fundamental principle of artesian flow. In the following para- 

'aphs only the principal artesian basins in the United States are 

riefly described.

138108° 39 4
176 CONTRIBUTIONS TO HYDBOLOGY, 1938-39

PALEOZOIC FORMATIONS OF EAST-CENTRAL REGION 

The Paleozoic rock systems of the interior of the United States, w 

of the Appalachian Mountains, form an extensive artesian basin, 

which the sandstones and to some extent the limestones are 1 

artesian aquifers, and the interbedded shales are the principal conf 

ing beds. The formations lie nearly horizontal over most of the in 

rior part of this region, but they rise gently in some areas, as 

northern Wisconsin and in Minnesota and in the Ozark Plateau, wh< 

the aquifers crop out. Recharge occurs at these somewhat elevai 

outcrops and also, according to available evidence, by slow downwa 

percolation through overlying formations in wide areas where t 

aquifers are not at the surface (2, 8, 21, 60, 64).

FIGUBE 19. Ideal section illustrating chief requisite conditions for artesian flows, a, Permeable WE 

bearing bed which constitutes the artesian aquifer; 6, c, impermeable beds or beds with relatively 

permeability that constitute the confining beds above and below the artesian aquifer; d, flowing wells. ' 

piezometric surface, which shows the height to which the water from the artesian aquifer will ris 

tightly cased wells, is indicated by the dasheci line. (After Chamberlin.)

The Mississippi River and its tributaries have cut rather bro 

valleys that are as much as several hundred feet below the gene: 

level of the land surface. Many flowing wells have been obtained 

these valleys, chiefly from the Cambrian and Ordovician sandston 

but the flowing wells are virtually confined to the valleys. Henct 

map of the area of artesian flow resembles a map of the drainage syste:

The strongest wells originally flowed several hundred gallons 

more than a thousand gallons a minute, but the head and rate of fl( 

have generally diminished, and in areas of heavy pumping the sta 

water levels have receded below the surface. The water has be 

extensively used for municipal and industrial supplies since the fii 

wells were drilled, more than 60 years ago, but because of the hi 

mineral content of much of the water and the receding head, there h 

been a tendency in recent years to replace these supplies with wal 

from other sources.

To a large extent the Paleozoic formations of the interior are belc 

sea level and have perhaps never been above the present level of t 

sea. Over much of the region there is almost no means of esca 

for the deep water and almost no head to induce movement. Throug 

out most of the region the deep water is salty, though different 

composition from the sea water. Thus there is reason to believe ths 

through the ages, there has been only very sluggish circulation throu. 

the deep-lying parts of the Paleozoic rocks and that the salty wal 

is largely connate or at least very ancient (9).

Within a few hundred feet of the surface there is more vigoro 

movement of the ground water from the upland areas of intake towa 

the stream valleys; consequently, the water in the Paleozoic rocks ne
M

FIGURE 20. Generalized section of the Roswell artesian basin. The artesian aquifer is a cavernous l

rain and snow on its elevated outcrop area and from the streams that flow over the outcrop are

exaggerated. (After Fiedler and Nye.)
178 CONTKIBUTIONS TO HYDKOLOGY? 1938-39

The confining member consists chiefly of Permian red beds that covei 

the limestone east of its outcrop area (6).

The artesian water is used for the irrigation of about 60,000 acres 

of land. Much of the water is pumped from wells that no longer 

overflow. Between 1905 and 1925 the head was notably lowered by 

the artesian discharge and pumpage from many wells of large capacity. 

At the same time the lowest lands became water-logged because oi 

the large quantities of artesian water that were wasted at the surface 

or by underground leakage from the wells. However, as a result of 

effective legal control and a program of repairing or sealing defective 

wells, most of the waste has been stopped, and the rate of withdrawal of 

artesian water by artesian flow or pumping is being kept close to the rate 

of recharge, with very beneficial results to agriculture and horticulture.

The flowing wells in the low parts of the area are still capable of 

very large yield. The rate of natural artesian flow from a well 

drilled in 1931, as measured, was 9,225 gallons a minute, or about 

13,000,000 gallons a day. Such wells, however, are now under 

strict control, as is obviously necessary.

FORMATIONS OF ATLANTIC AND GULF COASTAL PLAIN

The great succession of sedimentary beds ranging in age from 

Lower Cretaceous to Quaternary that underlies the Atlantic and 

Gulf Coastal Plain is stratigraphically and structurally favorable for 

the accumulation of artesian pressure (3, 13, 14, 26, 27, 28, 94). The 

artesian aquifers are the water-bearing sandstones and limestones, 

and the confining members are the shales and other strata of low 

permeability. As a rule the formations dip gently toward the sea or 

gulf. The intake of each formation is along the landward margin, 

where it is at or near the surface, and the formation passes thence to 

greater and greater depths in the direction of the coast. These 

conditions are illustrated in figures 21 and 22.

It is believed that some of the artesian aquifers have submarine 

outcrops that form potential outlets for the artesian water, whereas 

others pinch out or become impermeable at their seaward edge. In 

the aquifers that have outlets the fresh artesian water presses against 

the heavier sea water. If the head of the fresh water is relatively 

high and the submarine outlet is not too far below sea level, the fresh 

water discharges into the sea. Otherwise the sea water backs up into 

the aquifer and maintains a static condition, except as the fresh 

water may escape upward through the confining beds. In some 

places aquifers containing water of excellent quality occur below 

salt-water beds. Much of the fresh artesian water has been softened 

by natural base exchange. Flowing and pumped wells reduce the 

head and may thus cause the sea water to percolate toward them. 

To some extent the existing conditions may have been inherited from 

the Pleistocene epoch, when the sea stood at times higher and other
GROUND WATER 3N THE UNITED STATES 179

times lower than at present. This entire complex subject is receiving 

much critical study and will require much more.

Flowing wells, generally of low head, are obtained throughout a 

coastal lowland that ranges from a very narrow strip to a belt many

miles wide and also extends up the valleys of the rivers that cross 

the coastal plain and their tributaries. Flowing wells are therefore 

numerous and widely distributed. Most of them are of small diameter 

and rather small discharge and are used chiefly for domestic supplies. 

Many of them, however, originally flowed hundreds of gallons a minute.
180 CONTRIBUTIONS TO HYDROLOGY, 1938-39

 * * »

o o o o o

O O O O O

o o o o q

- t\T oo sf to

A well in St. Augustine 

Florida, ending in cavernous limestone at a depth of 

1,390 feet, was brought in 

with a natural artesian flow 

reported to be about 6,945 

gallons a minute, or about 

10,000,000 gallons a day. 

The numerous large supplies obtained from wells in 

many parts of the coastal 

plain are generally obtained 

by pumping, with considerable lowering of the head.

4 However, some large sup5 plies are still obtained by 

3 natural flow, as at Jacksoii- 

* ville, Florida, where flowing 

JH wells in permeable lime- 

| stone furnish the entire pub- 

| lie water supply of about 

I 12,500,000 gallons a day.

3

I CRETACEOUS FORMA1 TIONS OF GREAT 

\ PLAINS REGION

^ 

^

g The Cretaceous forma2 tions that underlie the northH

ern and central parts of the 

Great Plains region with 

much continuity have a 

stratigraphy and structure 

that is favorable for the development of great artesian 

pressure (4, 5, 25). The 

strata of sandstone, which lie 

mostly at or near the base 

of the Cretaceous system, 

form the principal artesian 

aquifers. The thick formations of plastic impermeable 

shale are exceptionally effective in confining the water in 

these sandstones and permitting the development of great artesian head. 

The Cretaceous formations are generally flexed up around the Black 

Hills and along the flanks of the mountains farther west, exposing the
era 5 FIGURE 23. Generalized section of the Dakota artesian basin in South Dakota. A, Sandstone of C

sedimentary formations; C, overlying sedimentary formations, including thick beds of impermeab

the profile of the original piezometric surface of the Cretaceous sandstone; it shows the height to 

(After Darton.)
182 CONTRIBUTIONS TO HYDROLOGY, 1938-39

remarkable achievement was due to the ingenuity and enterprise of 

Peter Norbeck, who adapted the jetting method to this purpose and 

directed the drilling of most of the wells. Norbeck later became 

Governor of South Dakota and then United States Senator.

As the number of wells increased the head and the flow declined 

gradually but persistently. The area of artesian flow, however, has 

shrunk only moderately, and most of the wells are still flowing, though 

in most places the head is low and the flow relatively small. An 

investigation by the North Dakota Geological Survey showed that in 

1935 there were about 4,400 flowing wells in that State, including a 

small proportion of wells drawing water from Tertiary and Pleistocene 

sources, and that these wells discharged by artesian pressure an average 

of somewhat less than 2 gallons a minute. Most of the Cretaceous 

wells were, however, throttled down, in accordance with the State 

law for the conservation of artesian water; otherwise the aggregate 

flow would have been considerably greater. In South Dakota the 

number of flowing wells is two to three times as great as in North 

Dakota, and the average discharge from a well is also greater.

Artesian sandstones occur at several horizons in most localities, but 

they have been only imperfectly correlated. In general, though with 

various exceptions, the strata that are first encountered yield rather 

soft water, high in sodium and in bicarbonate and chloride, whereas 

the deeper strata yield very hard water, higher in sulphate and lower 

in chloride. In many places the deeper water is still under great 

pressure, corroborating the chemical evidence of effective intervening 

confining beds.

The water is extensively used for livestock, but in many areas, and 

especially where it is high in fluoride, it is being replaced by water 

better for human consumption and industrial use. Some of the 

water, especially in Nebraska and Kansas, is too salty for any of the 

ordinary uses, though it is used to some extent for cooling installations. 

The soft water is generally unfit for use in irrigation.

The dynamics of the artesian system presents puzzling problems 

that require much more investigation. The artesian sandstones contain very large quantities of water, which, for the most part, is apparently moving very slowly from the western areas of outcrop, with their 

meager intake, in the direction of the hydraulic gradient originally 

toward the natural areas of discharge but now more generally toward 

the wells. The natural course of the water from intake to discharge 

probably required thousands of years, and some of the water may be 

virtually stationary in synclinal troughs or encased lenses. There is 

evidence that a large part of the great quantity of water discharged 

by the flowing wells has come more or less locally from storage as a 

result of external compression of the aquifers when the artesian pressure within the aquifers was relieved (16, 17).
GROUND WATER IN THE UNITED STATES 183 

GLACIAL DRIFT

The glacial drift that covers much of the northern part of the United 

States gives rise to thousands of flowing wells (8, 11, 12, 21, 25). 

These wells are situated in several hundred small and irregular areas 

of artesian flow chiefly but not exclusively within the area covered

0 10 20 30 40 50 60 MILES

0 10 40 SO KILOMETERS

FIGURE 24. Map of the lower peninsula of Michigan, showing areas of artesian flow, supplied chiefly from

glacial drift. (After Leverett.)

by the Wisconsin or latest drift sheet. (See, for example, fig. 24.) 

The artesian aquifers are the numerous and irregular bodies of sand 

and gravel that occur in the drift. The confining beds are deposits of 

boulder clay, especially of the ground moraine, or clayey deposits of

138108° 39 5
184 CONTRIBUTIONS TO HYDROLOGY, 1938-39

temporary glacial lakes. As the drift has a very irregular structure 

and includes much material that is more or less permeable, intake into 

the buried bodies of sand and gravel occurs in many indefinite areas 

where the water table is higher than the head of the water in these 

bodies, but the principal intake areas are the gravelly moraines that 

stand somewhat higher than the surrounding drift plains and in many 

places are connected with buried bodies of sand and gravel. The 

water that is absorbed by the moraines percolates slowly outward from 

them through the permeable materials beneath the boulder clay or lake 

beds, thereby creating artesian conditions.

Flowing wells are obtained in low places under a variety of conditions, largely at the base of moraines or in shallow stream valleys 

when the surface has been lowered somewhat without exposing the 

buried bodies of sand and gravel. The Wisconsin drift is so young 

that the area covered by it is very imperfectly drained, and the 

water table in this area is generally near the surface; hence a head 

in the deeper water only slightly greater than that at the water table 

produces artesian flows. As a rule there is upward leakage through 

the somewhat permeable confining beds, and consequently the head of 

flowing wells generally is low. Under exceptional conditions, however, 

there are wells with high head.

Throughout most of the Wisconsin drift area the water absorbed 

at the surface percolates through relatively unleached drift containing abundant organic matter. Hence the water from both flowing 

and pumped wells is commonly somewhat hard and iron-bearing but 

otherwise fairly satisfactory for domestic and other uses. There is, 

however, a wide range in the concentration of the dissolved constituents, corresponding to the character of the rocks from which the drift 

was derived.

Most of the flowing wells are of small diameter and yield, and they 

are found chiefly in villages and on farms, where they afford attractive 

and convenient supplies for domestic and stock use. Nearly all of 

the many large supplies obtained from glacial sand and gravel are 

pumped from wells of larger diameter and better construction.

VALLEY PILL OF WESTERN MOUNTAIN REGION

Flowing wells have been obtained in the low central parts of many 

of the valleys of the Western Mountain region that are underlain by 

detrital materials washed out from the adjacent mountains (10, 15, 

19, 20, 22, 23, 24, 58, 65). The artesian aquifers are the beds or trains 

of sand and gravel that extend irregularly from the mouths of the canyons, where the streams emerge from the mountains upon the alluvial 

fans of their own construction. The confining beds are formed in 

part by the more clayey or loamy alluvial deposits that overlie or 

encase the deposits of sand and gravel, especially in the lower parts of
GROUND WATER IN THE UNITED STATES 185

the valleys, and in part by the extensive beds of plastic and impermeable clay deposited in the lakes that occupied many of these valleys 

during the glacial stages of the Pleistocene epoch. The streams that 

rise in the mountains lose much or all of their flow on the gravelly 

upper parts of their-alluvial fans, where they build up the water table 

and thus furnish supplies, under artesian pressure, to the aquifers that 

extend below the confining beds in the low parts of the valleys. (See 

fig. 25.) As a rule, the largest and most productive areas of artesian 

flow are in the valleys that have not only Pleistocene lake beds or other 

effective confining beds but also abundant recharge from streams 

that drain large mountain areas with relatively heavy precipitation. 

Where lake beds are absent or poorly developed the confining beds 

generally permit considerable upward leakage and the flowing wells 

have only low or moderate head.

Notable for their size among the many areas of artesian flow are 

the extensive areas in the San Joaquin Valley, California (20), and

FIGUEE 25. Perspective view and section of a typical western valley showing artesian conditions. Cross 

ruling indicates saturated water-bearing beds; solid black indicates confining beds. Broken lines indicate 

boundaries of area of artesian flow.

in the San Luis Valley, Colorado (24). A survey made in 1936 

showed that there are more than 6,000 flowing wells in the San Luis 

Valley and that these wells have an average artesian flow under regulation of about 12 gallons a minute, or an average unrestricted flow 

of about 15 gallons a minute (23).

The area of artesian flow in the San Luis Valley has been expanded 

somewhat in certain localities as a result of irrigation with surface 

water and consequent seepage from ditches and irrigated land in the 

higher parts of the valley. In many valleys, however, the artesian 

flow and especially the heavy pumping from wells have lowered the head 

greatly and have caused the areas of artesian flow to shrink or to disappear entirely. Flowing wells are still used extensively in many valleys for domestic and stock supplies and also for irrigation, generally 

on a small scale. Nearly all of the many large supplies from the valley fill are, however, obtained by pumping.
186 CONTRIBUTIONS TO HYDROLOGY, 1938-39

DISCHARGE OF GROUND WATER THROUGH SPRINGS 

AND BY EVAPORATION AND TRANSPIRATION

GROUND-WATER DISCHARGE IN GENERAL

In most terranes, regardless of geologic age, in the eastern part of 

the United States where the climate is fairly humid, the stream systems receive water from numerous branches, which are fed at many 

points by effluent seepage and gradually increase in flow downstream. 

In the limestone terranes, however, whether of Paleozoic, Cretaceous, 

or Tertiary age, the spring-fed branches are generally fewer but the 

springs are commonly bolder, that is, their water flows freely from a 

single opening or only a few large openings.

In the eastern part of the United States it is estimated that at 

least one-third of the total ground-water discharge occurs by evaporation from the soil and by transpiration of trees and other plants. In 

summer the discharge by evaporation and transpiration may greatly 

exceed the discharge through springs, and the flow of small streams 

may diminish sharply or cease entirely (43). In the areas of Wisconsin drift the stream systems are poorly developed, and accordingly 

the water table stands high and there are many swampy tracts except 

where extensive systems of artificial drainage have been constructed. 

In the poorly drained areas the discharge of ground water by evaporation and transpiration is relatively large; on the other hand, in the 

limestone areas, where underground drainage channels are well developed, it is doubtless relatively small.

In going toward the less humid parts of the country, the total 

water intake and discharge decrease even more rapidly than does the 

precipitation, whereas the proportion of discharge by evaporation 

and transpiration increases. Consequently in the Great Plains region 

and in the southwestern extension of the East-Central region, springs 

are scarce and small, except in a few areas in which the geologic 

structure is especially favorable for producing springs (37). In the 

extensive areas of Pennsylvanian, Permian, and Cretaceous shale the 

conditions are especially unfavorable.

Over large upland areas in the Western Mountain region, springs 

and streams are absent or very scarce. In the high mountains, however, there are many streams that are fed perennially or during large 

parts of each year by melting snow and by springs. The mountain 

springs are of many kinds, but they are largely seepage springs that 

discharge ground water from the surficial materials where this water 

in its percolation encounters outcrops of hard, impermeable rock 

(15, 31, 33).

After the streams leave the mountains they flow down over their 

alluvial fans and lose all or a large part of their water by influent 

seepage (38). A large proportion of the stream valleys are tributary
GROUND WATER IF THE UNITED STATES 187

to closed drainage basins, the lowest parts of which are occupied by 

playas, or clay flats, over which the water from storm run-off and 

perhaps from meager perennial stream flow is spread until it evaporates. During parts of the Pleistocene epoch many of the closed 

basins contained lakes of considerable size, but most of these lakes 

have disappeared entirely and the few that still exist are only remnants of the Pleistocene lakes (39).

With respect to ground water the closed basins are of two kinds 

(1) those which lose all their ground water by subterranean leakage 

out of the basin, the water table being at considerable depth even in 

the lowest places; (2) those in which ground water is discharged in 

part by springs but generally in much greater quantities through, 

evaporation and transpiration, the water table being at or near tht! 

surface in the low central areas. (See fig. 26.) Basins of the seconc. 

kind are the most numerous, and economically they are by far the 

most important. The playas, which occupy the lowest parts of thq 

basins, are underlain by nearly impermeable clay, of Pleistocene 01* 

Recent age, which permits only a small amount of upward percolation. Near the margins of the playas there are commonly belts of 

springs that discharge the overflow of the underground reservoir. 

Surrounding the playas are broad belts of characteristic deser; 

plants, called phreatophytes, which habitually obtain their water 

supplies by sending their roots down to the water table. The 

phreatophyte vegetation Us invariably arranged in concentric beltp 

or zones, certain species, such as the common salt grass (Distichlis 

spicata), occupying the inner belt where the water table is near 

the surface, and other species, such as greasewood (Sarcobatus vermiculatis) in the northern basin and mesquite (Prosopis) in ths 

southern basins, occupying the outer belt where the water table is 

farther below the surface but still within reach of these deep-rooted 

phreatophytes (42, 48, 65).

The great bodies of basalt and other volcanic rocks give rise to hug 

springs of excellent water that are the largest in the United States.

LARGE SPRINGS

In 1923 the author of this paper called attention to the need for 

classification of springs according to their rate of discharge and prc 

posed two systems of classification one based on the metric system, 

the other on the units commonly used in the United States. Accorc 

ing to the second system, a spring of the first magnitude is one that hg s 

an average discharge of not less than 100 cubic feet per second which 

amounts to an average daily discharge of 65,000,000 gallons, or 250,000 

cubic meters (40).

According to a study completed about 10 years ago (41), there are 

in the United States 65 springs of the first magnitude. (See fig. 27.)
188 CONTRIBUTIONS TO HYDROLOGY, 1938-39

 / .. . . ... ./.». -r.

 . « - . ; /. /. . -- \

' ::-£m \

Mountain area that discharges surface water

Area in which the valley

Area in which the valley 

fill is discharging ground 

water by evaporation and 

transpiration of plants. 

The dense shading shows 

tracts practically barren 

of vegetation. The remaining parts support

native plants which habitually obtain their water 

supplies from the zone of 

saturation

Approximate depths to 

.the.water table in feet

Boundary of drainage basin

FIGURE 26. Map of the northern drainage basin of Big Smoky Valley, Nevada, showing intake and discharge of ground water.
PI.

trt o

03

O

O I'

"^ etet- CD

tr pCK2

o>

SB >-i 

CD

PL,

o 5*

FIGUKE 27. Map of the United States showing springs of the first magnitude that is, springs, w

discharge of more than 100 cubic feet a second, which amounts to more than 65,000
190 CONTRIBUTIONS TO HYDROLOGY, 1938-39

Paleozoic age, 8 of them in the Ozark area of Missouri and Arkansas; 

4 are in Lower Cretaceous limestone in the Balcones fault belt in 

Texas; and 11 are in Tertiary limestone in Florida. The 3 springs 

that issue from sandstone are in Montana. The great discharge of 

these springs is believed to be due to faults or to other special features. 

With the additional data now available, some revision of these figures 

could be made but it would be of minor character.

The recorded discharge (generally the average of available measurements) of a few of the largest springs and groups of springs is given in 

the following table.

Recorded discharge of very large springs and groups of springs in the United

States

SPRINGS IN VOLCANIC ROCK OR ASSOCIATED GRAVEL: 

Sheep Bridge Spring, Oreg

Springs along 10-mile stretch of Metrolius River, Oreg-. __ ..

Springs along 10-mile stretch of Fall River, Calif _ _ _____

Malade Springs, Idaho _ _ .__ .- __ _ ..-.

SPRINGS IN LIMESTONE:

Silver Spring, Fla ____ ____________________

SPRINGS IN SANDSTONE:

Cubic feet 

a second

323

1,070

1,400

1,133

864

5,085

428

330

808

Gallons a 

day

209, 000. 000

692, 000. 000

905, 000. 000

732, 000. 000

3. 787, 000, 000

914 fin.fi nnn

522, 000, 000

Cubic 

meters a 

day

791,000

2, 619, 000

3, 425, 000

2, 761. 000

2,112,000

14, 334, 000

Qi A AAH

i Q7c Ann

1 

' 447 000

THERMAL SPRINGS

An exact statement of the number of thermal springs in the United 

States is, of course, arbitrary, depending upon the classification of 

springs that are only slightly warmer than the normal for their 

localities and upon the groupings of those recognized as thermal 

springs.

A recently published report (45) lists 1,059 thermal springs or spring 

localities. Of these 52 are in the East-Central region (46 in the Appalachian Highlands and 6 in the Ouachita area in Arkansas), 3 are in the 

Great Plains region (in the Black Hills of South Dakota), and all the 

rest are in the Western Mountain region. (See fig. 28 ) The States 

having the largest number of thermal springs, according to the listing 

in the report, are Idaho 203, California 184, Nevada 174, Wyoming 116, 

and Oregon 105. The geyser area of Yellowstone National Park, 

however, exceeds all others in the abundance of springs of high temperature (29). Indeed, the number of thermal springs in this area 

might be given as several thousand if the springs were counted individually instead of being grouped.

Nearly two-thirds of the recognized thermal springs issue from igneous rocks chiefly from the large intrusive masses, such as the great 

Idaho batholith, which still retain some of their original heat. Few, if
GROUND WATER I2sT THE UNITED STATES 191

any, derive their heat from the extrusive lavas, which were widely 

spread out in relatively thin sheets that cooled quickly. Many of the

thermal springs issue along faults, and some of these may be artesian 

in character, but most of them probably derive their heat from hot

138108° 39 6
192 CONTRIBUTIONS TO HYDROLOGY, 1938-39

gases or liquids that rise from underlying bodies of intrusive rock. 

The available data indicate that the thermal springs of the Western 

Mountain region derive their water chiefly from surface sources, but 

their heat largely from magmatic sources (29, 45). The thermal 

springs in the Appalachian Highlands owe their heat to the artesian 

structure, the water entering the aquifer at a relatively high altitude, 

passing to considerable depth through a syncline or other inverted 

siphon, and reappearing at a lower altitude; in the deep part of its 

course the water is warmed by the normal heat of the deep-lying rocks 

(36, 44).

It has been estimated that the aggregate flow of all thermal springs 

in the United States is not more than 500,000 gallons a minute (45). 

The average discharge of 177 thermal springs in California on which 

data are available is 91 gallons a minute. The largest thermal 

spring in the United States is probably Warm Spring, in Montana, 

which has a temperature of only 68° F. (20° C.) but has a discharge of 

about 80,000 gallons a minute.

EBBING AND PLOWING SPRINGS

Ebbing and flowing or periodic springs are distinctly different in 

origin and operation from the ordinary intermittent springs that flow 

in wet seasons and disappear in dry seasons (30, 32, 34, 35, 46). An 

ebbing and flowing spring has periods of flow, when it flows vigorously, 

and periods of ebb, when it ceases to flow or flows at a greatly reduced 

rate. The periods of flow may occur at nearly regular intervals or 

at very irregular intervals; they may occur at intervals of a few 

minutes, a few hours, a few days, or even longer. All or nearly all 

of the springs of this type issue from limestone. Nearly all are situated far from the ocean, and they have no relation whatever to 

oceanic tides. In their periodic action they resemble geysers, but 

their water has the normal temperature of ordinary ground water, 

and they do not generally emit any noticeable amount of gas.

After many years of inquiry and search incidental to other work, 

there have been located in the United States a total of only 23 springs 

of this kind, of which 9 are in Virginia, 4 in Missouri, 3 in Tennessee, 

2 in West Virginia, and 1 each in Nevada, New Mexico, Pennsylvania 

Utah, and Wyoming. The largest and most spectacular of these 

springs is the so-called "Geyser Spring" near Afton, Wyo., which at 

maximum flow on September 29, 1933, had a measured discharge of 

about 17,000 gallons a minute.

Automatic recorders have been maintained on several of these 

springs. A nearly continuous record for a period of more than 

5 years was obtained for the so-called "tide spring," near Broadway, 

Va. (See fig. 29.) Study of the springs and of their perform-
GROUND WATER IN THE UNITED STATES 193

Noon

Dec. 13,1927

Mar. 19,1928

Apr. 28,1928

Feet

- 1.0

-0.5 

0.0

- 1.0

-0.5 

0.0

-1.0

-0.5 

0.0

Apr.30,1928 -

AJIAAJUUU 

 JUMVJU

TIDE SPRING" NEAR

- 1,0

-0.5 

_n n

BROADWAY, VA.

Get, 2, (928

Oct. 10,1929

Aug. 4,1930

Aug.14,1930

- 1.5

- 1.0

-0.5 

0.0

- 1.5

- 1.0

-0.5 

0.0

- 1.5

- 1.0

-0.5 

0.0

.5 

-h 1.0 

hO.5 

0.0

"GEYSER SPRING" NEAR AFTON, WYO.

FIGURE 29. Hydrographs, for selected days, of the ebbing and flowing springs near Broadway, Virginia, 

and Afton, Wyoming. The spring near Broadway was gaged under the direction of J. J. Dirzulaitis, 

and the spring near Afton under the direction of H. T. Stearns.
194 CONTRIBUTIONS TO HYDROLOGY, 1938-39

ances, as shown by the continuous records, seems to confirm 

the theory that this action is that of natural siphons and suggests 

that their irregularities are caused chiefly by variations in water 

supply and in air-tightness of the siphon system resulting from 

alternations of wet and dry seasons.

UTILIZATION OF GROUND WATER

PUBLIC WATERWORKS

The United States is notable for the large number of public waterworks, the high quality of the water that they serve, the generous and 

varied use that is made of the water, and the ample supplies that are 

furnished (50a).

Exact data in regard to the waterworks of the entire country are 

not available, but sufficient information has been obtained by the 

Geological Survey, chiefly from the State health departments, to serve 

as a basis for estimates that give an essentially correct perspective of 

the conditions. About 10,000 communities have public waterworks 

of some sort. As reported in the 1930 census, these communities have 

an aggregate population of about 75,000,000, out of a total population 

of the country of about 123,000,000. The per capita consumption of 

water in these communities probably averages as much as 125 gallons 

a day.

The large cities obtain their public water supplies chiefly from surface sources, and the small communities chiefly from wells. Of the 

25 cities that have a population of more than 300,000 all obtain, their 

supplies from streams or lakes, except that a few of these have supplementary supplies of ground water. In 1930 the aggregate population of these 25 cities was about 25,000,000, and the total population 

of all the cities supplied wholly or chiefly from surface sources or 

from springs is estimated to have been about 55,000,000. The supplies are generally ample, except for some of the smaller cities, and 

almost without exception the water, after treatment, is of good sanitary 

quality.

About 6,500 communities, with an aggregate population of about 

20,000,000, having public waterworks supplied wholly or chiefly from 

wells or other structures for recovering ground water (54). This 

number includes 15 of the 68 cities having a population between 

100,000 and 300,000; somewhat less than one-third of the 283 cities 

between 25,000 and 100,000; about one-half of the 1,457 cities between 

5,000 and 25,000; and about two-thirds of the approximately 8,000 

smaller communities that have public waterworks. The cities between 

100,000 and 300,000 that have water supplies derived from wells or 

comparable structures, named in the order of their population, are as 

follows: Houston, Memphis, San Antonio, Dayton, Des Moines, Long 

Beach, Jacksonville, Camden, Spokane, Wichita, Miami, Peoria,
GROUND WATER IN THE UNITED STATES 195

Canton (Ohio), El Paso, and Lowell (Massachusetts). The proportional distribution of public waterworks supplied from wells is shown, 

by States, in figure 30.

It is roughly estimated that about 2,000,000,000 gallons of ground 

water are obtained daily through wells or similar structures for public 

water supplies in the United States. The largest ground-water development for public supplies is in the western part of Long Island, New 

York, in New York City and the adjacent county of Nassau (56). The 

average pumpage from wells and infiltration galleries for all purposes in 

that area during the period from 1904 to 1937, has been somewhat 

over 158,000,000 gallons a day, of which about 113,000,000 gallons

FIGURE 30. Map showing the States in which most of the public water supplies are derived from wells. 

(From Eng. News^Record, vol. 110, p. 750.)

has been for the public supplies of New York City and suburbs. In the 

Houston-Galveston area, in Texas, the use of ground water has increased progressively since the beginning of this century, and in 1936 

it averaged about 98,000,000 gallons a day, of which about 25,000,000 

gallons was for the public supply of Houston.

As might be expected, the many small waterworks supplied with 

ground water vary greatly both as to quantity and quality of the 

water. However, with the constantly increasing vigilance of the 

State and local health departments, these supplies are with few exceptions of good sanitary quality. Moreover, in the recent droughts the 

public water supplies from wells have generally been adequate, and 

the difficulties on account of failing supplies have been chiefly in the 

smaller communities that depended on surface water without adequate 

storage.
196 CONTRIBUTIONS TO HYDROLOGY, 1938-39 

DOMESTIC SUPPLIES

One of the greatest achievements in American history has been the 

progressive development of domestic water supplies of good quality 

that is, the water supplies used by the people for drinking, cooking, and 

laundry and toilet purposes.

In the pioneer period the domestic supplies were obtained chiefly 

from springs or from shallow dug wells that were generally unreliable 

and exposed to pollution. In contrast, a very large proportion of the 

75,000,000 people who now live in communities that are served by 

public waterworks have ample and perennial supplies of safe, acceptable water delivered under pressure to the taps in their kitchens, bathrooms, and laundries. Within the communities that have public 

waterworks, including large cities, there are still a considerable number 

of people who obtain their domestic supplies from private wells. The 

supplies from many of these wells are subject to pollution and are 

otherwise unsatisfactory, and they should for the most part be 

abandoned in favor of the supplies furnished by the public waterworks.

It is estimated that there are in the United States between 3,000 

and 4,000 communities of less than 1,000 inhabitants that are provided 

with public water supplies. However, according to the 1930 census, 

the total number of incorporated places having less than 1,000 inhabitants is slightly over 10,000 and their aggregate population is 

somewhat more than 4,000,000. It may therefore be inferred that 

there are still several thousand of the smaller incorporated communities, with an aggregate population of perhaps 2,000,000, that do 

not have public water supplies. Most of the people in these communities have private wells.

According to the 1930 census there are nearly 45,000,000 people 

who live in rural territory that is, in homes that are widely distributed on about 6,500,000 farms and in the very small rural communities that are not incorporated. It should be noted that the 

United States differs from most other countries in that the people 

engaged in agriculture do not generally live in compact communities 

but in widely separated homes on the individual farms. It is not 

generally practicable to supply these homes from public waterworks, 

but as a rule each farmer has developed a private supply for the 

household, or in some cases more than one household, on his farm.

By far the largest number of the rural inhabitants obtain their 

domestic water from private wells, but a considerable number obtain 

it from springs, and some depend on rain water stored in cisterns, 

water in irrigation ditches, or other sources. In the hard-water 

areas it is common practice for a household to have two distinct 

sources of supply a well that provides hard but otherwise relatively 

acceptable water for drinking and cooking, and a cistern that provides 

soft water for laundry and toilet use.
GROUND WATER IN THE UNITED STATES 197

Obviously it is, in the aggregate, a very large and difficult task to 

develop so many water supplies under the great variety of groundwater conditions that prevail throughout the country. Much progress 

has been made, not in any one year but through the successive decades 

since the different sections of the country were settled by the white 

men. The ideal is to provide every rural home with an ample, reliable, 

and convenient supply of water that is safe from pollution and otherwise of acceptable quality. Much work must yet be done before this 

ideal can be even approximately realized.

The development of improved private water supplies has been 

largely the work of many thousands of water-well drillers. Most of 

these drillers have operated on a small scale, in restricted territory, 

and until recently they have depended chiefly on their own ingenuity, 

with very little help from any outside source. In 1915 the well drillers 

in North Dakota organized an association with the help of H. E. 

Simpson, who later became the State geologist. Following this 

precedent, about 15 other State or regional associations of water-well 

drillers have been organized, and in 1929 was organized the American 

Association of Water Well Drillers. This movement is essentially 

an educational enterprise to improve the condition of the industry 

and the welfare of the individual drillers through the application of 

better technical and business methods.- The value of the movement 

to the public probably cannot easily be overestimated. Its effectiveness is largely due to the cordial cooperation of the Federal and 

State geological surveys and health departments, the State colleges 

and universities, other State organizations that are concerned with 

water supplies, and the National Research Council. An essential 

factor in the success of the movement has been the generous support 

given by the commercial supply houses, a few of which are publishing 

technical journals that are of great benefit to the drillers.

The development of satisfactory water supplies is not entirely a 

matter of deeper drilling, for much of the best water occurs near the 

surface. It is rather a matter of intelligent action, with due consideration of the problems of each specific locality, by men who are 

well informed and experienced in developing ground-water supplies 

a matter of selecting the proper location and the proper water-bearing 

bed and of installing wells of the proper type and construction to 

give satisfactory perennial service and maximum protection from 

pollution.

As yet, only a small proportion of the rural homes are provided 

with adequate plumbing facilities and water-supply systems that 

deliver water under pressure to the kitchen, bathrooms, and laundry. 

However, the number of homes that are thus equipped is constantly 

increasing, and it may be expected that with the prospective general
198 CONTRIBUTIONS TO HYDROLOGY, 1938-39

electrification of rural homes the greater part of the rural inhabitants 

will have water-supply facilities comparable to those of the city 

residents.

LIVESTOCK SUPPLIES

The livestock industry is a very important and widely distributed 

industry in the United States. It does not need any large individual 

supplies of water, and the requirements as to both sanitary and 

chemical quality are considered to be much less rigorous than for 

human use. However, supplies in adequate quantity are necessary 

at very many places to enable the livestock to utilize all the available 

forage. Moreover, the failure of the water supplies may cause 

serious inconvenience or financial loss to the stockmen, especially in 

times of drought, when the feed also is scarce. Consequently, the 

development of water supplies for livestock has been a large achievement for the country as a whole, and it still presents acute problems 

in some areas, especially in the shale areas of the Great Plains region 

and the southwestern part of the East-Central region and in the open 

range of the Western Mountain region.

The water supplies used for livestock are to a great extent the same 

as the rural domestic supplies, but on many farms the domestic supplies are obtained from wells whereas the animals obtain their water 

from springs or streams. Where ground water is scarce, as in the 

shale areas and parts of the arid region, many small earth dams are 

built to impound storm water. These supplies are valuable but 

many of them fail at times when water is most needed. Recently 

the Grazing Division of the United States Department of the Interior 

has been active in sinking wells, improving springs, and constructing 

small reservoirs on extensive tracts of the public domain in the arid 

parts of the country.

INDUSTRIAL SUPPLIES

Water supplies other than the public supplies are obtained from 

wells for a very large number of industrial and other establishments, 

including the many railroad systems, factories and mills of many 

kinds, metal and oil refineries, creameries and dairies, canneries, power 

plants, refrigerating and air-conditioning plants, public institutions, 

hotels, sanitariums, and recreational establishments. These supplies 

range from only a few thousand gallons to several million gallons a 

day. New supplies are constantly being developed from wells. 

Recently there have been developments in many places for airconditioiiing projects and some very large developments for paper 

pulp mills.
GROUND WATER IN THE UNITED STATES 199

The water supplies from wells are especially valuable in the many 

places where supplies are not available from any public waterworks. 

However, among the industrial establishments that are supplied with 

water from their own wells are many located in New York, Chicago, 

Philadelphia, and most of the other communities, both large and small, 

that have public waterworks. The water from the private wells is 

preferred to the public supplies chiefly where it is cheaper or where the 

constant low temperature of the ground water is an advantage, as in 

condensing, refrigerating, or air-conditioning. In many communities 

the water from the private wells is harder and less satisfactory for 

boiler use than is the water served by the public waterworks, but in 

some places it is preferred for certain industrial processes. In a very 

few places water from thermal springs or wells is used for heating 

buildings.

IRRIGATION SUPPLIES

According to the statistics obtained by the United States Census 

Bureau for the principal States in which irrigation is practiced, about 

2,117,000 acres in these States was irrigated in 1929 with water from 

wells about 11 percent of the total irrigated area (49). This irrigation was accomplished by the use of about 4,800 flowing wells and 

about 56,700 pumped wells, only between 2 and 3 percent of the area 

irrigated with ground water being supplied by flowing wells.

The aggregate capacity of the flowing wells hi 1929 is recorded as 

about 877,000,000 gallons a day, and the aggregate capacity of the 

pumped wells as about 46,753,000,000 gallons a day. Because of the 

tendency of many well owners to overestimate the capacity of their 

wells, it is probable that this reported pumping capacity is considerably greater than the actual total capacity of the wells. At any rate, 

it gives no indication of the quantity of ground water actually used 

or actually available for irrigation. Thus, if it is assumed that in 

1929 the average depth of water applied to the land that was irrigated 

by wells was 2 feet, the total quantity of water from wells actually 

used in that year was about 4,234,000 acre-feet, or an average throughout the year of about 3,777,000,000 gallons a day. This computation 

seems to indicate that, on the average, the irrigation wells were in 

use less than one-tenth of the total time. It indicates that the total 

quantity of water withdrawn from wells for irrigation was, very 

roughly, about twice the quantity withdrawn from wells for public 

waterworks and between one-third and one-half the total quantity of 

both surface and ground water furnished by all the public waterworks 

hi the country. Since 1929 there has been a large increase in the use 

of water from wells for irrigation in some States and probably a substantial increase in the aggregate annual withdrawal for irrigation.
200 CONTRIBUTIONS TO HYDROLOGY, 1938-39

With respect to the areas irrigated with water from wells, the 

Census Bureau shows that in 1929 the States ranked as indicated in 

the following table:

Areas in States west of the Mississippi River, including Louisiana, irrigated with

water from wells in 1929

Utah... ..........................................................

Idaho, Oresron, Nevada, Montana, South Dakota, Wyoming,

Area

Acres

1, 464, 960 

175, 787 

142, 978 

106, 002 

62, 624 

58, 118 

23, 452 

20,995 

19, 655 

15, 929 

11, 651

10, 976

2, 117, 018

Hectares 

(approximate)

593, 000 

71,000 

58, 000 

43, 000 

25, 300 

23, 500 

9,500 

8,500 

7,900 

6,400 

4,700

4,400

856, 000

Percent of 

total

69.2 

8.3 

6.8 

5.0 

3.0 

2.8 

1.1 

1.0 

.9 

.8 

.6

.5

100

The water for irrigation obtained from wells is used largely for fruits, 

vegetables, and other relatively valuable crops. The valuable 

orchards of oranges and other citrus fruits in southern California are 

largely irrigated with water from wells. It has been estimated that 

in the intensively developed south coastal basin of California, in 

which Los Angeles is located, underground sources furnish about 90 

percent of the water supply originating within the basin hi the 

summer for irrigation and municipal purposes (69). A general study 

of the census statistics leads to the conclusion that for all irrigation 

in the States covered, the value of the water from wells is probably 

equal to about one-fourth the value of the surface water.

In some of the States the amount of irrigation with water from 

wells has been small, not so much because of lack of supply but 

rather because it has not been found profitable to pump the water 

for the crops of relatively low value that could be raised. In these 

States considerable additional developments can be made without 

exceeding the safe yield whenever methods can be developed that are 

economically feasible. More intensive quantitative studies are 

needed to determine the supplies of ground water that are available 

for irrigation and to find methods for utilizing the ground water to 

supplement rainfall and surface-water irrigation and to provide 

small-scale irrigation in connection with "dry-farming" and stockraising.

In Arkansas, Louisiana, and eastern Texas the irrigation is nearly 

all for raising rice. In the eastern part of the United States water
GROUND WATER IN THE UNITED STATES 201

from wells is used on many small tracts for the commercial production 

of vegetables and fruits, especially in Florida, other parts of the 

Atlantic and Gulf Coastal Plain, and Michigan. Water from wells 

is also used extensively throughout the eastern part of the country 

for sprinkling lawns, golf courses, and domestic gardens.

The relatively small aggregate area irrigated with water from flowing 

wells in the western States is widely distributed among many low 

valley tracts. Nearly half of the area is in the Roswell artesian basin 

in New Mexico. In Florida several thousand flowing wells are used 

to supply water for irrigating celery and other vegetables and citrus 

fruits. Thus Florida ranks high in the number of flowing wells used 

for irrigation and in the value of the crops irrigated by flowing wells.

USES FOB HEALTH AND RECREATION

There are in the United States a number of health resorts at watering places that have excellent hotels and recreational facilities and 

are well equipped for treating disease. Some of these are at thermal 

springs; others, as Saratoga Springs, N. Y., are at springs that yield 

water of normal temperature. In addition to these well-known and 

well-appointed resorts, there are many that are only modestly or 

poorly equipped.

The earliest interest in thermal springs in the United States lay in 

their use as health resorts, and many of the health resorts that are at 

present widely known and patronized are located at thermal springs. 

Of 1,059 thermal springs listed in the recently published paper on 

thermal springs in the United States (45), a total of 184 are reported 

to be used as resorts, including sanitariums, and about 110 others 

are reported as having facilities for bathing. Of the remaining 765 

thermal springs, about 175 are reported as being employed locally 

for domestic and public supplies, and a considerable number are used 

for irrigation and watering livestock. About 400 are reported as 

not used.

Resorts or sanitariums at thermal springs are reported in 18 States. 

California is reported to have 53, Montana 18, Colorado 17, Idaho 

16, Nevada 15, and Oregon 14. Though the greater number are in 

the western part of the United States, some of the best known and 

best equipped are in the eastern part, as, for example, Hot Springs, 

in Arkansas (52); Warm Springs, in Georgia (36); and Hot Springs, 

in Virginia (52, 53).

The latest year for which statistics were obtained by the Government in regard to the production of mineral waters was 1923 (50). 

In that year sales were reported from 433 commercial springs, in 44 

different States, amounting, to about 45,000,000 gallons. The reports 

included natural waters that were sold for medicinal or table use but
202 CONTRIBUTIONS TO HYDROLOGY, 1938-39

not waters that were used in the manufacture of soft drinks. The 

report for 1923 states that of the mineral waters as above defined, the 

medicinal waters represent only about 13 percent of the total in value 

and a much smaller proportion of the total quantity. The mineralwater trade is now largely in waters, in their natural state or carbonated, that are sold as pure and wholesome drinking water for 

offices and homes. The mineral-water industry is under strict control of the Food and Drug Administration of the United States 

Department of Agriculture (51, 55).

In the, United States less attention is given to health resorts at 

watering places than in some other countries, and the sale of medicinal 

and table waters is also relatively small. These conditions are probably due largely to (1) the prevalence of adequate plumbing and bathroom facilities in a large proportion of the American homes, with 

ample supplies of hot and cold running water; (2) the abundant and 

convenient supplies of safe and palatable drinking water in nearly 

all cities and* in a large number of the smaller communities and rural 

homes; and (3) the habit of most of the American people to drink 

freely the water from their own public or private supplies. The 

American people rank high in the personal use of water, both external 

and internal, and, they doubtless also rank higher than is generally 

assumed in its therapeutic use.

METHODS AND RESULTS OF GROUND-WATER 

INVESTIGATIONS IN THE UNITED STATES

Ground-water investigations are of two principal kinds systematic 

areal surveys and special investigations, which are generally more 

intensive and contribute to a more detailed knowledge of hydrologic 

principles.

The earliest ground-water work necessarily consisted chiefly of 

reconnaissance over large regions that had not previously been 

investigated. Gradually the reconnaissance surveys were succeeded 

by more thorough and systematic surveys. As the ground-water 

surveys by the Federal Geological Survey are carried on only as 

financial cooperation is furnished by individual States, it has not been 

possible to cover all the States in accordance with any uniform plan, 

and in some parts of the country the ground-water conditions are 

still known only in a general way. However, the Ground Water 

Division of the Geological Survey has long visualized a systematic 

survey of the entire area of the United States with respect to the 

ground-water conditions and resources, and it has endeavored to 

standardize methods for carrying out this survey as opportunity is 

afforded.
GROUND WATER IN THE UNITED STATES 203 

SYSTEMATIC GROUND-WATER SURVEYS

The common units in the systematic ground-water survey are the 

counties, of which there are 3,070 in the United States, but in Connecticut the unit has been the town, and in many parts of the Western 

Mountain region such geomorphic units as valleys or drainage basins 

have been used. An individual water-supply paper may contain the 

results of the study of an entire State; it may cover a group of counties, in which case it generally contains a unit description of each 

county; or it may cover only a single county, in which case it generally 

includes a brief description of each township or geomorphic unit in 

the county.

Pennsylvania affords an example of a systematic ground-water 

survey in that the entire State has been covered by a survey that is 

relatively uniform and fairly adequate, although not so intensive as 

the surveys in some other parts of the country. Pennsylvania has 

an area of 45,126 square miles and a population of nearly 10,000,000. 

It is divided into 67 counties. The ground-water survey has been 

carried on somewhat intermittently since 1925 but is now completed. 

The results have been published by the State Geological Survey in a 

series of six volumes, designated Bulletins Wl, W2, W3, W4, W5, 

and W6, ea,ch of which covers a group of counties and includes a unit 

description of each of these counties. On pages 223 227 are listed 24 

representative papers that give the results of systematic ground-water 

surveys (4, 8, 14, 15, 20, 21, 22, 25, 26, 28, 32, 33, 37, 38, 47, 57-65).

A typical report of this kind consists of three parts general discussion, stratigraphic description, and description by counties.

The general discussion covers briefly the geography, precipitation, 

stream flow, stratigraphy, and rock structure. It covers more fully 

the source, occurrence, quantity, quality, and temperature of the 

ground water; the head of the ground water and the artesian conditions; the distribution, character, and size of the springs; the 

recovery and utilization of the ground water; and the methods of 

constructing wells and improving springs. It generally includes a 

table of rock formations that has one column in which the quantity 

and quality of the water in each formation is concisely stated.

The stratigraphic description treats each formation in more detail 

its occurrence, depth below the surface, stratigraphic and structural 

relations, thickness, lithologic character, and water-bearing properties; the head and quality of its water, and the development and 

value of the water for water supplies.

The county descriptions give more details concerning the groundwater conditions and the developments in each county and each 

locality. They generally include logs of specific wells, tables giving 

the available data in regard to individual wells and springs, and 

chemical analyses of the waters from some of them.
204 CONTRIBUTIONS TO HYDROLOGY, 1938-39

In 1917 the Geological Survey reestablished its water laboratory, in 

which chemical analyses of both surface and ground waters are made 

under rigorous control. In this laboratory several thousand samples 

of water have been analyzed, and analyses representing the water 

from a large number of water-bearing formations throughout the 

country have been published or placed in the open files of the 

Geological Survey.

In 1923 a hydrologic laboratory was established in the Geological 

Survey (91). In this laboratory tests have been made of certain 

physical properties of about 2,000 samples of material from many 

different water-bearing and non-water-bearing formations, the results 

of most of which have been published. The tests usually made are 

for mechanical composition, permeability, porosity, and moisture 

equivalent the last two being used to compute the specific retention 

and specific yield (84, 91). The laboratory has also been used to a 

small extent for research work. There are, of course, many other 

laboratories in the United States in which are made chemical analyses 

of water and physical tests of natural earth materials.

A water-supply paper that presents the results of a systematic 

ground-water survey generally includes one or more maps showing 

the geology of the area covered, the location of wells and springs, 

and certain other features, such as depth to the principal aquifers 

and structure contours on them, depth to the water table and contours on the water table, contours on one or more of the piezometric 

or pressure surfaces, areas of artesian flow, areas of ground-water 

discharge by evaporation or by transpiration from plants of certain 

species, and areal variations in the chemical character of the water.

Maps showing changes in ground-water conditions are found 

chiefly in the water-supply papers that are based on rather intensive 

investigations. Such papers may contain maps showing contours 

on the water table or on the piezometric surfaces on different dates 

and maps showing the original areas of artesian flow and the areas of 

artesian flow at specified subsequent dates.

INTENSIVE GROUND-WATER INVESTIGATIONS

Quantitative problems. In many centers of population and industry 

and in many areas where water is needed for irrigation, ground water 

is being withdrawn from wells in such large quantities that the problems of overdraft and safe yield are becoming very serious and urgent. 

For many years the intensive studies of ground water have been 

chiefly quantitative. They involve for each formation and each 

area the problems of the quantity of water in storage, the proportion 

of the stored water that can be recovered through wells, the average 

rate of natural intake or recharge, the proportion of the recharge
GROUND WATER IN THE UNITED STATES 205

that can be recovered through wells, the effects of the withdrawals 

through wells upon water supplies derived from natural discharge of 

ground water, the extent to which the rate of recharge can be increased, 

and the effects of artificial methods for recharge upon the surfacewater supplies.

Quantitative investigations were in progress in the early years of 

the present century, chiefly in California and on Long Island, New 

York (74, 75, 83, 87, 88, 89, 98). In subsequent years, even though 

the funds for ground-water investigations were extremely meager, the 

quantitative problems were being studied and steady progress was 

made in the analysis of these problems and the development of 

methods for their investigation. In 1919 the author of this paper 

presented before the Geological Society of America a paper on quantitative methods of estimating ground-water supplies (80). At that 

time this subject was still regarded as somewhat academic; since then 

its great practical importance has come to be generally recognized.

In the paper just cited, the methods of estimating ground-water 

supplies were classified in four groups intake, discharge, water-table, 

and underflow methods. This classification has since served as a 

frame work for planning quantitative investigations.

In 1928 the author presented before the Society of Economic Geologists a more detailed paper which contained also references to the 

principal publications issued up to that time on the different phases 

of the subject. This paper was published in 1932 (81), and although 

substantial progress in the study has since been made, this paper still 

serves fairly well as an outline of available quantitative methods.

In this second paper the concept was developed that some of the 

water-bearing formations function chiefly as underground reservoirs 

and others chiefly as underground conduits but that to some extent 

all of them function in both ways. It was shown further that quantitative methods based on the reservoir concept are applicable chiefly, 

though not exclusively, to formations or parts of formations that have 

a water table, whereas methods based on the conduit concept are 

applicable chiefly to artesian formations, in which the water moves 

laterally under pressure for considerable distances from the intake 

area to the discharge area.

The exacting requirements of the quantitative studies have resulted 

in substantial clarification of the principles of ground-water hydrology 

and in the development of an effective technique for ground-water 

studies, thus opening a large field for further research.

Molecular attraction. The rock formations consist largely of 

porous materials with small interstices. In some formations a 

cubic foot of the porous material contains a few acres of intersticial 

surface, and the molecular attraction of this aggregate surface exerts 

a powerful control over the ground water that has no equivalent in
206 CONTRIBUTIONS TO HYDROLOGY, 1938-39

the hydraulics of surface water. Indeed, it is largely the force of 

molecular attraction that makes ground-water hydrology a distinct 

science requiring a technique of its own (1).

The molecular attraction may be strong enough to hold only a small 

part of the stored water, or a large part, or all of it. The specific 

retention of a porous material furnishes a quantitative expression of 

the effectiveness of molecular atti action in the material. It is the 

volume of water held against the pull of gravity, expressed as a percentage of the volume of material drained.

The counterpart of specific retention is specific yield. It is the 

volume of water that can be withdrawn from a water-bearing formation with a given lowering of the water table, also expressed in percentage of the volume of the material drained. The specific retention 

and the specific yield of a material together equal the porosity. 

Various methods have been devised for determining specific retention 

and specific yield, but the subject is complicated by the time factor 

and in other ways and should receive much more thorough investigation. (See references 1, 40, 69, 92, and 99.)

Recharge. Considerable data are now available on the depletion 

of the moisture in the belt of soil water, or root zone, which comprises 

the surficial material from which water is withdrawn through evaporation or by the roots of plants; also on the relatively constant moisture 

content, approximating the specific retention, of the intermediate belt, 

which is next below the belt of soil moisture. The water absorbed 

from rain and snow is held in the root zone until the approximate 

limit of specific retention is reached; thereafter in permeable material 

it responds to the force of gravity and tends to move down to the 

water table. Recent investigations have shown impressively that 

with light precipitation the absorbed water may all, or nearly all, be 

held in the root zone even though the soil and rocks afford good intake 

facilities, whereas with heavier precipitation and similar intake 

facilities there may be large recharge of the ground-water supply. 

There is now evidence that recharge may occur by the inconspicuous 

process of gradual fattening and subsequent thinning of the moisture 

films on the interstitial surfaces in the intermediate belt, the thinning 

being in response to the force of gravity. (See references 40, 66, 

72, 99.)

Investigations have shown that, under favorable conditions, the 

rate of recharge can be substantially increased by pumping, whereby 

the "water table is lowered and underground storage is provided for 

surface water that would otherwise be rejected (10, 69, 75, 78, 89, 96). 

In California artificial recharge by spreading the flood waters of influent streams over permeable terranes has long been under investigation and is now practiced to a considerable extent (83a). Wells
GROUND WATER IN THE UNITED STATES 207

have long been used in some limestone terranes for draining swampy 

land and unfortunately also locally for disposal of sewage, but they 

have not been much used as intake openings to augment the water 

supplies of sand and gravel formations. Recently, however, recharge 

wells have come into use in certain places in California, and on Long 

Island the attempt has been made to return through wells water 

that has been used for air conditioning. The methods and problems 

of such operations are being studied. The recent droughts have 

created great interest in artificial recharge by the construction of 

small reservoirs, and the national program of soil conservation has 

raised questions as to the effects of terracing and of different methods 

of tilling, fertilizing, and cropping upon the amount of water from rain 

and snow that penetrates to the water table. Several investigations 

of these problems have been started, chiefly by obtaining records of 

fluctuations of water levels in wells, and it appears that in the near 

future the entire subject will receive the intensive study that it 

deserves.

Discharge of ground water, A notable American contribution to 

ground-water hydrology is the recognition and study of the plant species called phreatophytes, which in the arid regions are rather sharply 

distinguished from the true xerophytes by their habit of obtaining 

their water supplies from the water table. Methods have been 

developed for determining the quantities of ground water discharged 

by such plants. The quantative determinations are based on daily 

fluctuations of the water table, the ratio of water consumed to dry 

vegetable matter produced by growth, and other factors. (See 

references 42, 48, 65, 66, 67, 75, and 96.)

The so-called channel-storage method of determining effluent 

seepage appears to be opening a promising field of investigation 

(43, 73, 82). A continuous record of the quantity of ground water 

that seeps into a selected small drainage system is obtained by a 

single stream-gaging station that has been rated not only for discharge 

but also for channel storage, the channel-storage rating being accomplished by the use of many subsidiary gage-height stations that show 

the cross-section areas and hence the volume of water in successive 

segments of the streams. Except in periods of rain or melting of 

snow, when there is overland run-off, the method should give the rate 

of effluent seepage in each short interval of time, and should thus give 

a basis for studying the relation of this rate to many different factors, 

such as rainfall, melting of snow, freezing and thawing of the soil, 

amount of soil moisture, fluctuations of the water table in the valleys 

and on the uplands, bank storage, perched ground water, evaporation 

and transpiration, and fluctuations in atmospheric pressure.

Water table, capillary fringe, and piezometric surface. The water 

table is of primary significance in the occurrence and movement of the
208 CONTRIBUTIONS TO HYDROLOGY, 1938-39

ground water. If a well is sunk into a permeable material just to the 

point where water enters the well and forms a water surface in it, 

that surface marks the hydrostatic level of the water at the top of the 

zone of saturation; by definition, it indicates the position of the water 

table at that place. Wherever there is a body of permeable material 

that is saturated with water in its lower part, there is a zone of saturation and a water table whether basal or perched; whether permanent, 

temporary, or very ephemeral.

The capillary fringe is immediately above the water table and may 

be as much as several feet in thickness. In it water under the control 

of molecular attraction may not merely cling in films on the interstitial 

surfaces but may fully occupy the interstitial chambers as in any 

other capillary tubes (1, 40). The force of molecular attraction becomes active in pulling up water through the capillary interstices 

whenever water is removed from the capillary fringe by evaporation 

or absorption by the roots and whenever the water table rises. The 

capillary fringe and the precise phenomena of its functioning have 

received considerable study but still present puzzling problems that 

bear in a large way on the practical problems of recharge and discharge.

In a permeable material that has interstices of capillary size, the 

water table is not a water surface such as the water surface in the well. 

It is an imaginary surface that marks the hydrostatic level of the water 

in the zone of saturation. The water surface in the permeable material is the upper surface of the capillary fringe. It is above the 

water table and is much more irregular, consisting of many little surfaces that are concave upward, each occupying an interstitial chamber 

that may be connected with its neighbor by a tiny strait or walled off 

from it by a grain of sand.

If a body of permeable material overlain by an impermeable formation is completely saturated with water under pressure, a well will 

strike water when it reaches the bottom of the impermeable formation 

and the water will rise in the well to its hydrostatic level, which may be 

below or above the land surface. The hydrostatic level marks the 

position of the piezometric surface of the confined water. Such a 

piezometric surface is functionally very different from a water table.

Impermeable bodies grade in size from that of a particle smaller 

than a grain of sand to that of the most extensive artesian confining 

bed. Therefore, although typical water-table conditions and typical 

artesian conditions are sharply differentiated, they grade into each 

other in a manner analogous to the gradation between the vegetable 

and animal kingdoms or between their major branches.

Movement of ground water. The construction of contour maps of 

the water table and of the piezometric surfaces of the artesian aquifers 

has become a prominent part of ground-water investigations. These 

maps show the hydraulic gradient and the direction in which the
GROUND WATER IN THE UNITED STATES 209

ground water is moving in all localities that they cover, and hence, to 

a great extent, they show the source and destination of the ground 

water.

The development of the concept of the third dimension in the movement of ground water has resulted in a better understanding of artesian conditions. It is now recognized that there are vertical as well 

as lateral hydraulic gradients, that confining beds are generally not 

entirely impermeable, and that percolation across the strata is of 

major importance in the recharge and discharge of many of the 

artesian aquifers.

Water-bearing formations which throughout their extent have a 

water table generally have extensive intake areas and good intake 

facilities, and the discharge from many of them occurs in widely 

distributed localities relatively near to or even coinciding with the 

areas of intake (78, 89, 97). Such formations function chiefly as 

reservoirs, and if they have a considerable specific yield and lie in a 

region of abundant precipitation their perennial yield may be very 

large, as for example on Long Island. In the essentially artesian 

formations, which have a water table only in restricted areas and 

extend laterally beneath confining beds through long distances, the 

perennial yield may be limited by the rate of recharge in the intake 

areas or by the rate at which the water percolates laterally from the 

intake area to the area of natural discharge or to the wells where the 

water is utilized. If the intake area is in a region of abundant precipitation and the intake facilities are fairly good, the limiting condition is likely to be the rate of percolation and therefore the formation 

must be studied chiefly in its function as a conduit.

The simple law of laminar flow, developed by the French investigator Poiseuille and applied to water-bearing material by the French 

hydrologist Darcy, is one of the basic laws of ground-water hydrology 

on which the ground-water conduit investigations in the United States 

are based. It merely postulates that in any given material at a given 

temperature the rate of flow is directly proportional to the hydraulic 

gradient. Thus the capacity of any ground-water conduit can be 

computed as the product of its cross-section area, its coefficient of 

permeability (corrected for the existing temperature), and the hydraulic gradient of its water. Because of the fundamental importance of 

Darcy's law the range of its validity has been thoroughly studied in 

this country, and these studies have shown that the law holds for 

relatively high gradients in very permeable materials (104) and also 

for extremely low gradients and low velocities (70). Thus, in tests 

made in the hydrologic laboratory of the Geological Survey on a fine 

to medium sand, Darcy's law was found to hold with a gradient of 

only 2 or 3 inches to the mile (about 1:25,000).
210 CONTETBUTIONS TO HYDEOLOGY, 1938-39.

Because of the urgent need for determining the perennial yield of 

the many artesian formations in the United States, it became necessary to develop practicable methods for obtaining the average permeability of these formations. The subject has been given much 

intensive study both in the laboratory and in the field, but it presents 

complex problems that will require more study. (See references 18, 

74, 81, 87, 88, 91, 93, 94, 97, and 99.)

The limitations of the laboratory methods are due chiefly to the 

multitudinous difficulties encountered in obtaining representative 

samples. Some appreciation of these difficulties may be gained from 

the fact that the most permeable material tested in the hydrologic 

laboratory of the Geological Survey carries water at a rate about 

450,000,000 times that of the least permeable material that was 

tested.

The early field work was based on the method of determining the 

rate of movement of salt introduced into the ground water, which was 

developed by the German hydrologist, Adolph Thiem, and was improved in this country by C. S. Slichter, who made effective use of an 

electric current instead of chemical tests (88). It was found, however, that this method, like the laboratory method, has many practical 

limitations. Later, the method developed by Gunter Thiem was 

introduced, and this has led to experiments in which observations 

have been made of the rate and amount of drawdown and recovery 

of water levels in numerous observation wells within the cones of 

depression of discharging wells under both water-table and artesian 

conditions (99). Intensive studies based on the data obtained in 

these experiments have been fruitful in determining not only permeability but also specific yield and elasticity of water-bearing 

formations. Mention should also be made of the successful results 

obtained in the use of uranin dye to trace in detail the course of ground 

water in sand under water-table conditions, and the course of bacteria 

introduced into the ground water (92).

Compression and expansion of aquifers. One of the most significant 

of recent discoveries is that in some way many of the artesian aquifers 

have sufficient volume elasticity to yield large quantities of water from 

storage when the expansive force of the artesian pressure is reduced 

and to store large quantities when the artesian pressure is restored 

(16, 17). Thus it is recognized that until the reservoir function of 

the great artesian aquifers can be evaluated their perennial yield 

cannot be definitely determined, and estimates of perennial yield 

that do not take account of the withdrawal from storage in the early 

stages of development may be too optimistic. This subject is being 

actively investigated, and methods are becoming available for making
GROUND WATER IN THE UNITED STATES 211

quantitative determinations of change in storage by compression and 

expansion of the formation (93).

Contamination by salt water. Problems relating to the contamination of supplies of fresh ground water by salt water are becoming 

increasingly important. The salt water is generally drawn into the 

formations in which fresh water is stored and thence into the producing wells by heavy pumping. The salt water may move laterally in a 

water-bearing stratum or vertically across the strata; it may be preexisting salty ground water or may come directly from the sea. The 

principle of the balance between the relatively heavy sea water and 

the lighter fresh ground water is expressed in what is called the 

Ghyben-Herzberg law, which was developed by Dutch and German 

investigators (68). This principle is being effectively applied in this 

country under a variety of water-table and artesian conditions (27, 

63, 68, 78, 79, 89, 94). A recent method of study is to have observation 

wells, often called "pilot wells," from which samples are taken periodically for the determination of chloride, thus to obtain advance notice 

of the lateral or vertical encroachment of salt water.

Test wells. Geologic study has been based chiefly on natural 

exposures of rock formations and on artificial exposures made in 

mining, well digging and drilling, grading for railroads and highways, 

and excavation for other purposes. From the observations made at 

such random exposures data have been obtained from which the 

stratigraphy and structure of the rocks at intervening points and at 

greater depths can be more or less accurately determined. Most of 

the natural exposures and many of the artificial exposures, however, 

are above the water table and therefore do not have the same determinative value for studies of the occurrence, quantity, head, and 

quality of ground water that they do for studies of stratigraphy and 

structure. Information in regard to ground water must be obtained 

largely from wells and other excavations that extend below the water 

table, and many ground-water studies have been severely handicapped by lack of adequate well data. In the past the funds 

available generally have not been sufficient to permit test drilling, 

but with the greatly increased appreciation of the value of ground 

water and of ground-water investigation, the sinking of test wells 

of some sort is now a part of the program of most of the groundwater work done by the Geological Survey.

Apparatus used in ground-water studies. The study of artesian 

conditions and salt-water problems has been advanced by the development of current meters, electrical salinity apparatus, and samplers 

for use in wells (77, 79). With this apparatus it is feasible to detect 

leaks in the casings and to determine the sources of both fresh and 

salt water. A technique has also been developed for determining the
212 CONTRIBUTIONS TO HYDROLOGY, 1938-39

source of salt water by frequent sampling of the water pumped from 

a well, especially at the beginning of pumping operations.

The possibilities of using different geophysical methods in groundwater studies are being investigated (71). Surveys of the electric resistivity of the earth are being made to determine the depth to bodies 

of salt water and their lateral extent; also to distinguish between beds 

of coarse materials that yield water freely and beds of fine-grained 

materials that yield little or no water. The salt water is detected by 

its low electric resistivity; the productive water-bearing materials are 

detected by their high resistivity as compared with that of the finegrained, unproductive materials. Plans have been considered for using 

electric resistivity in place of pilot wells for detecting the encroachment 

of salt water; also, in investigations of rainfall penetration, for determining changes in the moisture content of the material between the 

land surface and the water table.

The principal instruments of precision in ground-water investigations in the United States have come to be the automatic water-stage 

recorders installed over observation wells (76). For a long time automatic recorders have been used occasionally on wells, but their systematic use and the critical study of the records was begun only about 

15 years ago (94). Automatic recorders are now in operation on a few 

hundred wells in different sections of the country, representing a wide 

diversity of ground-water conditions. About 200 automatic recorders 

are being used on wells by the Geological Survey and cooperating 

agencies. Most of the instruments record water levels in wells by 

means of floats but some are pressure recorders. Improvements are 

constantly being made in the instruments to adapt them better to 

the conditions under which they must be used on wells.

Fluctuations of water levels. The accurate continuous records obtained from these instruments have made almost sensational revelations, showing that both water tables and artesian pressures are constantly fluctuating in complicated fashion in response to a variety of 

impinging forces (81). Thus, the way has been opened for making 

exact and critical studies of the dynamics of the ground water and of 

the properties of the ground-water reservoirs and conduits. However, as the fluctuations are seldom the effects of simple forces acting 

singly, careful selection of the observation wells and painstaking 

analysis of the records are necessary for evaluation of the effects of 

specific forces. For example, great interest was aroused at first when 

hydrographs were obtained that closely resembled the barographs at 

the same place; then the fluctuations produced by changes in atmospheric pressure came to be regarded merely as a bothersome interference with the records of significant fluctuations; now it is becoming 

evident that much is yet to be learned from the differences in the
GROUND WATER IN THE UNITED STATES 213

degree of response to changes in atmospheric pressure. In figures 31 

to 41 are given hydrographs showing fluctuations in water levels in 

wells produced by several different causes precipitation, evaporation

1928 1929 1930 1931

Z 

24

BACON

ROSS

WELL

WELL

\

1928 1929 1930 1931 1932 1933

FIGURE 31. Graphs of water levels in two shallow wells in Virginia, near Washington, D. O., showing 

fluctuations caused by precipitation and seasonal variations in evaporation and transpiration. The 

monthly precipitation is that recorded at Washington, by the U. S. Weather Bureau. (Geol. Survey 

Water-Supply Paper 840, pp. 618 and 619, 1938.)

and transpiration, pumping, variations in atmospheric pressure, ocean 

tides, earth tides, earthquakes, and railroad trains. All these hydrographs are reproductions of graphs obtained by the Geological Survey 

on automatic recorders.
214 CONTRIBUTIONS TO HYDROLOGY, 1938-39

£t

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FI&TTBE 32. Graphs of water levels in wells in Escalante Valley, Utah, showing discharge of ground water 

by transpiration. A, Shallow well in field of alfalfa; shows draw-down of the water table during a part of 

each day caused hy transpiration. B, Shallow well in cleared field adjoining the alfalfa field; shows absence of discharge by transpiration. (After W. N. White. Geol. Survey Water-Supply Paper 659, p. 

42, 1932.)

2

p

I 4.60

Oct. 

14

B

FIGURE 33. Graphs of water level in a shallow well in Escalanto Valley, Utah, showing discharge of ground 

water by transpiration. A, Shows discharge by transpiration of willows in the summer; B, shows absence 

of such discharge in the autumn, after the vegetation had become dormant. (After W. N. White. (Geol. 

Survey Water-Supply Paper 659, p. 40, 1932.)
GROUND WATER IN THE UNITED STATES 215

17 18 19

JULY 1938 

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FIGXTBE 34. Graphs of water levels in two observation wells showing fluctuations caused by pumping 

third well. Well A is 256 feet from the pumped well; well B is 356 feet from the pumped well.
Fri. Sun. Mon. Tues. Wed. Thurs. Fri.

6 739 10 II

MARCH 1927

FIGUEE 35. Graph of water level in a well 200 feet deep, near Lodi, California, showing daily and weekly 

fluctuations caused by pumping from other wells for irrigation during the daytime, except on Sundays; 

also abrupt fluctuations caused by the passing of trains, except on Sundays, over a railroad 117 feet from 

the well. (After H. T. Stearns and T. W. Robinson. Economic Geology, vol. 23, p. 276, 1928.)

TIME IN SECONDS

2O 30 4O 50 60

EASTBOUND PASSENGER TRAIN-LOCOMOTIVE AND 4CARS

TIME IN MINUTES 

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LONG ISLAND RAILROAD

SMITHTOWN STATION

100 0 100 500 Feet

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PLAT SHOWING LOCATION OF WELL.RAILROAD.AND STATION

FIGURE 36. Graphs of water levels in 90-foot artesian well at Smithtown, Long Island. New York, showing 

effects of passing railroad trains. (After C. E. Jacob. American Geoph. Union Trans. for 1939, in press.)
June 15, 1930 16 17

-16.1

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FIGUKE 37. Graph of water level in a well 200 feet deep at The Dalles, Oregon, showing fluctuations caused 

States Weather Bureau at The Dalles (circles) and at Portland (continuous line). The fluctuations in a

of the water level when converted from inches of mercury to feet of water. (After A. M. Piper. Ge
218 CONTRIBUTIONS TO HYDROLOGY, 1938-39

:-70

JULY 1938 

6 7 8 9 10 II

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^\ S~^ /-\ ^x

^ X,

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ARTESIAN WELL

5m TIDE GAGE

FIGUEE 38. Graph of water level in an artesian well 100 feet from the shore, showing fluctuations caused 

by the ocean tide that occurs in Mattawoman Creek, Maryland. During the period shown there was 

only slight change in the atmospheric pressure.

\

OCEAN TIDE AT ATLANTIC CITY

°2L

\N

N

/

^

.

/

LONGP }RT V\

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FIGUEE 39. Graph of water level in a well 800 feet deep near the coast at Atlantic City, New Jersey, showing 

fluctuations caused by the ocean tide on January 22,1926, when the rising tide was interrupted by a strong 

northwest wind. The tide was recorded by a gage of the United States Coast and Geodetic Survey. 

(After Paul Schureman. Geog. Rev., p. 481, 1926.)
GROUND WATER IN THE UNITED STATES 219

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5 £ MARCH 1938 * 

10 II 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

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FIGURE 40. Graph of water level in a 270-foot well near Carlsbad, New Mexico, about 500 miles from the 

sea, and supplementary graphs showing an earth tide. Curve at top is believed to show semidaily tidal 

fluctuations, more distirct at full moon than at first and last quarters; compiled from actual instrumental 

record (shown in the middle) by correcting for effects of fluctuations in atmospheric pressure. Water in 

well is a brine of 1.2 density. Barometric efficiency of the well, as determined by inspection, is about 70 

percent. Curve at bottom, accordingly, sbows 70 percent of the fluctuation in atmospberic pressure, 

expressed in feet of brine of 1.2 density. Vertical lines on the curve at the top show the time of the transit 

of the moon. (After T. W. Eobinson and C. V. Theis. American Geophys. Union Trans. for 1939, in 

press.)

In recent years the Geological Survey and cooperating agencies have 

undertaken to develop a nation-wide program of observation wells. 

A permanent committee on observation wells has prepared a manual 

of methods (76), and annual reports are now being published that 

contain the records of water levels and artesian pressure in the wells 

equipped with automatic recorders and in several thousand wells that 

are observed periodically in different parts of the country. These 

reports are in the nature of inventories, showing from year to year 

the net depletion or replenishment of the ground-water supplies in 

different formations and different areas.
220 CONTRIBUTIONS TO HYDROLOGY, 1938-39

In the areas of large withdrawals by pumping or artesian flow, the 

ultimate answer to the question of maximum perennial yield must be 

obtained from records of monthly or annual withdrawals together with 

correlative records of fluctuations of water levels and artesian pressure.

March, 1934 

14 9

-a-

 3-

Well N 

Depth-10 A

Well No.81 

Depth

Wel 

Depth

Na82 

 \OBfee

Well No. 101 

Oerth=68feet

Well No. 102 

"\^S- -\Degth-90feel.

ZIX

FIGURE 41. Graphs of water levels in five wells in Ogden Valley, Utah, showing fluctuations caused by 

earthquakes on March 12,1934. (After R. M. Leggette and G. H. Taylor. Geol. Survey Water-Supply 

Paper 7%, p. 129, 1937.)

Neither withdrawal records nor water-level and pressure records alone 

are adequate to indicate the magnitude of the perennial supply. 

Therefore, a vigorous effort is being made to obtain both sets of data 

for the areas in which large use is made of the ground water.

WORK OF THE GEOLOGICAL SURVEY AND COOPERATING

AGENCIES

In the period of rapid settlement of the country in the last third of 

the 19th century, there was widespread activity in well drilling, and 

flowing wells were obtained in many places. The interest in groundwater supplies led to numerous investigations, by both Federal and 

State geological surveys, of the ground-water conditions in the 

different parts of the country largely reconnaissance surveys of
GROUND WATER IN THE UNITED STATES 221

extensive areas but also some intensive studies. The period of active 

ground-water investigation extended for several years into the 20th 

century. Then there was a reduction in the annual appropriation for 

the water-resources work of the Federal Geological Survey and, 

particularly, a great reduction in the allotment for ground-water 

investigations. It appears that about the same time there was also 

general curtailment by the State geological surveys of their groundwater work.

For many years after this decline, ground-water investigations 

were conducted on a meager scale, quite out of proportion to the 

importance and complexity of the subject. In the fiscal year 1918 

a survey of desert watering places was made (Water-Supply Papers 

490, 497, 498, 499, and 578), and exploratory drilling for irrigation 

supplies was done (Water-Supply Paper 467), both by the Ground

ater Division of the Geological Survey as a result of special appronations by Congress. In that year and the following year there was 

much demand for ground-water investigations for special war puroses, investigations being made by the Ground Water Division at 

more than 100 military establishments.

Since 1918, there has been a progressively large increase in the funds 

annually made available for ground-water investigation and a corresponding improvement in the quality of the technical work done. The 

demand came first from the States, which supplied funds for cooperation with the Ground Water Division. At the same time there was a 

similar demand for more stream gaging, which likewise was supported 

chiefly by State funds. Since the fiscal year 1929 Congress has 

ecognized these needs by making increased appropriations for investigation of the water resources of the country by the Geological Survey. 

Congress has, however, restricted the major part of the water resources 

appropriations to use for cooperation with State, county, or municipal 

governments, and has provided further that in such cooperation the 

contribution from Federal funds should in no case exceed 50 percent. 

The growth of interest in the ground-water resources of the country is 

shown approximately by the increase in funds expended by the Geological Survey and cooperating State and local governmental organizations in the last 30 years. In the 10-year period covering the fiscal 

years 1908 to 1917 the expenditures for ground-water investigations 

by the Geological Survey and cooperating agencies averaged less than 

$20,000 a year; whereas in 1939, as a result of the interest and financial 

support of State and local agencies, the expenditures amounted to 

about $375,000.
222 CONTRIBUTIONS TO HYDROLOGY, 1938-39

The Geological Survey has published about 700 papers that contain 

information on the subject of ground water, of which about 400 relate 

primarily to this subject. See "List of publications of the Geological 

Survey, United States Department of the Interior" (reissued about 

every two years); also ''Bibliography and index of publications of the 

United States Geological Survey relating to ground water" (Water 

Supply Paper 427, 1918). In the fiscal year 1937 the Geological 

Survey and cooperating agencies released 75 papers giving the results 

of technical studies regarding ground water. Of these, 5 were published by the Geological Survey as individual water-supply papers and 

3 as contributions to hydrology; 6 were published by cooperating 

State or Territorial organizations; 17 were published in technical 

journals; 31 were mimeographed (chiefly by cooperating States); and 

13 were released in typewritten form. In 1938 a total of about 100 

ground-water papers were released, of which 4 were published as 

water-supply papers and 5 as contributions to hydrology.

The technical literature relating to ground water in the United 

States exclusive of that published by the Geological Survey, is extensive and widely scattered. Practically all technical ground-water 

papers published in this country since 1928, except those that are 

purely engineering in character, are listed in the "Annotated Bibliography of Economic Geology," which is issued semiannually under 

the auspices of the National Research Council. The principal groundwater papers published since 1935 are listed in the "Bibliography of 

Hydrology," which is to be published annually by the American Geophysical Union as a part of the international bibliography on the 

subject.

A list of representative papers relating to different phases of the 

subject is given on pages 223-229 of this paper for the use of those 

readers who wish to make further study of the subject. Many of 

the papers listed contain bibliographies or numerous references to 

other publications on the same phase of the subject.

SOURCES OF DATA FOB THIS PAPER

In the present paper the section relating to water-bearing formations is based chiefly on the author's paper entitled "The occurrence 

of ground water in the United States, with a discussion of principles" 

(No. 1 in the following list). That paper contains references to numerous substantial publications by many authors, covering different 

parts of this large subject. Many of the other papers in the list 

also contain systematic descriptions of water-bearing formations in 

different parts of the country. '
GROUND WATER IN THE UNITED STATES 223

Information on the principles of artesian water and on the artesian 

conditions in different parts of the country is widely scattered through 

nany publications chiefly reports by the Federal and State geologcal surveys. .A number of representative reports are cited.

The section relating to springs and evaporation discharge of ground 

 vater is also based on many publications, some of which are cited in 

;he list. The discussion of large springs is based chiefly on No. 41, 

ind that of thermal springs on No. 45. The published information 

m ebbing and flowing springs is meager and scattered but there are 

mpublished records in the Geological Survey.

The section relating to the utilization of ground water is based 

chiefly on the publications cited but in part on other publications and 

m unpublished records in the Geological Survey. The statements 

~egarding public waterworks are based in part on No. 54 and on other 

publications, of which No. 56 is representative; chiefly, however, on 

mpublished records collected by D. G. Thompson from the State 

.lealth departments and other sources. The statements regarding use 

:or irrigation are based chiefly on the census report (No. 49) but also on 

Dther sources. The statements regarding uses for health and recreaion are based largely on Nos. 45 and 50. The papers listed as Nos. 

51, 52, 53, and 55 were presented at a meeting of the American 

Chemical Society at Atlanta, Ga., in 1930, and were published in 

[ndustrial and Engineering Chemistry. Together they furnish a 

learly up-to-date survey of conditions affecting the mineral-water 

Dusiness.

LIST OF REPRESENTATIVE PUBLICATIONS IN THE UNITED STATES 

RELATING TO GROUND WATER

WATER-BEARING FORMATIONS AND THEIR GEOGRAPHIC DISTRIBUTION

1. Meinzer, O. E., The occurrence of ground water in the United States, with a 

discussion of principles: Geol. Survey Water-Supply Paper 489, 1923. 

Contains reference to numerous publications that cover different parts of 

this subject. Many of the other publications in this list also contain systematic descriptions of water-bearing formations.

WATER-TABLE CONDITIONS

See especially the following papers in this list: Nos. 1, 6, 8, 13, 14, 15, 20, 21, 25, 

26, 28, 32, 37, 38, 40, 43, 47, 56-61, 63-65, 69, 75, 78, 83, 89, 90, and 97.

ARTESIAN CONDITIONS

2. Chamberlin, T. C., The requisite and qualifying conditions of artesian wells: 

U. S. Geol. Survey 5th Ann. Kept., pp. 125-173, 1885.

3. Darton, N. H., Artesian-well prospects in the Atlantic Coastal Plain region: 

U. S. Geol. Survey Bull. 138, 1896.

4. Darton, N. H., Geology and underground waters of South Dakota: U. S. 

Geol. Survey Water-Supply Paper 227, 1909.
224 CONTRIBUTIONS TO HYDROLOGY, 1938-39

5. Dart on, N. H., Artesian waters in the vicinity of the Black Hills, Soutt 

Dakota: U. S. Geol. Survey Water-Supply Paper 428, 1918.

6. Fiedler, A. G., and Nye, S. S., Geology and ground-water resources of the 

Roswell artesian basin, New Mexico: U. S. Geol. Survey Water-Supplj 

Paper 639, 1933.

7. Fuller, M. L., Summary of the controlling factors of artesian flows: U. S. 

Geol. Survey Bull. 319, 1908.

8. Hall, C. W., Meinzer, O. E., and Fuller, M. L., Geology and undergrounc 

waters of southern Minnesota: U. S. Geol. Survey Water-Supply Papei 

256, 1911.

9. Lane, A. C., Lower Michigan mineral waters, a study into the connectior 

between their chemical composition and mode of occurrence: U. S. Geol 

Survey Water-Supply Paper 31, 1899.

10. Leggette, R. M., and Taylor, G. H., Geology and ground-water resources oi 

Ogden Valley, Utah: U. S. Geol. Survey Water-Supply Paper 796-D, 1937

11. Leverett, Frank, and others, Flowing wells and municipal water supplies in 

the southern portion of the southern peninsula of Michigan: U. S. Geol. 

Survey Water-Supply Paper 182, 1906.

12. Leverett, Frank, and others, Flowing wells and municipal water supplies in 

the middle and northern portions of the southern peninsula of Michigan: 

U. S. Geol. Survey Water-Supply Paper 183, 1907.

13. Livingston, Penn, Sayre, A. N., and White, W. N., Water resources of the 

Edwards limestone in the San Antonio area, Texas: U. S. Geol. Survey 

Water-Supply Paper 773-B, 1936.

14. Lonsdale, J. T., and Day, J. R., Geology and ground-water resources of 

Webb County, Texas: U. S. Geol. Survey Water-Supply Paper 778, 1937.

15. Meinzer, O. E., Ground water in Juab, Millard, and Iron Counties, Utah: 

U. S. Geol. Survey Water-Supply Paper 277, 1911.

16. Meinzer, O. E., and Hard, H. A., The artesian-water supply of the Dakota 

sandstone in North Dakota, with special reference to the Edgeley quadrangle: U. S. Geol. Survey Water-Supply Paper 520-E, 1925.

17. Meinzer, O. E., Compressibility and elasticity of artesian aquifers: Econ. 

Geology, vol. 23, no. 13, pp. 263-291, May 1928.

18. Meinzer, O. E., Movements of ground water: Am. Assoc. Petroleum Geologists Bull., vol. 20, no. 6, 1936.

19. Mendenhall, W. C., Ground waters of the Indio region, California, with a 

sketch of the Colorado Desert: U. S. Geol. Survey Water-Supply Paper 

225, 1909.

20. Mendenhall, W. C., Dole, R. B., and Stabler, Herman, Ground water in 

San Joaquin Valley, California: U. S. Geol. Survey Water-Supply Paper 

398, 1916.

21. Norton, W. H., Hendrixson, W. S., Simpson, H. E., Meinzer, O. E., and 

others, Underground-water resources of Iowa: U. S. Geol. Survey WaterSupply Paper 293, 1912.

22. Richardson, G. B., Underground water in the valleys of Utah Lake and 

Jordan River, Utah: U. S. Geol. Survey Water-Supply Paper 157, 1906.

23. Robinson, T. W., and Waite, H. A., Ground water in the San Luis Valley, 

Colorado: National Resources Committee, Regional planning, pt. 6, 

The Rio Grande Joint Investigation, pp. 226-261, 1938.

24. Siebenthal, C. E., Geology and water resources of the San Luis Valley, 

Colorado: U. S. Geol. Survey Water-Supply Paper 240, 1910.

25. Simpson, H. E., Geology and ground-water resources of North Dakota, 

with a discussion of the chemical character of the water, by H. B. Riffenburg: U. S. Geol. Survey Water-Supply Paper 598, 1929.
GROUND WATER IN THE UNITED STATES 225

26. Stephenson, L. W., Logan, W. N., and Waring, G. A., The ground-water 

resources of Mississippi, with discussions of the chemical character of the 

waters, by C. S. Howard: U. S. Geol. Survey Water-Supply Paper 576, 

1928.

27% Stringfield, V. T., Artesian water in the Florida peninsula: U. S. Geol. 

Survey Water-Supply Paper 773-C, 1936.

28. Veatch, A. C., Geology and underground-water resources of northern 

Louisiana and southern Arkansas: U. S. Geol. Survey Prof. Paper 46, 1906.

DISCHARGE OP GROUND WATER THROUGH SPRINGS AND BY EVAPORATION AND

TRANSPIRATION

29. Alien, E. T., and Day, A. L., Hot Springs of the Yellowstone National Park, 

Carnegie Inst. Washington, 1935.

30. Bridge, Josiah, Ebb and flow springs in the Ozarks: Missouri Univ., School 

of Mines and Metallurgy, Bull., vol. 7, no. 1, pp. 17-26, 1923.

31. Bryan, Kirk, Classification of springs: Jour. Geology, vol. 27, pp. 522-561, 

1919.

32. Cady, R. C., Ground-water resources of the Shenandoah Valley, Virginia: 

Virginia Geol. Survey Bull. 45, 1936. (See especially the contribution 

by O. E. Meinzer on ebbing and flowing springs, pp. 52-54.)

33. Gregory, H. E., The Navajo Country, a geographic and hydrographie 

reconnaissance of parts of Arizona, New Mexico, and Utah: U. S. Geol. 

Survey Water-Supply Paper 380, 1916.

34. Hall, G. M., Note on an ebb and flow spring near Rogersville, Tennessee: 

Tennessee Acad. Sci. Jour., vol. 3, pp. 3-9, 1928.

35. Hall, G. M., The "fittifying" spring near Greenbrier Cove, Tennessee: 

Tennessee Acad. Sci. Jour., vol. 11, no. 2, 1936.

36. Hewett, D. F., The Warm Springs of Georgia, their geologic relations and 

origin: U. S. Geol. Survey Water-Supply Paper 819, 1937.

37. Lugn, A. L., and Wenzel, L. K., Geology and ground-water resources of 

south-central Nebraska: United States Geol. Survey Water-Supply 

Paper 779, 1938.

38. Meinzer, O. E., Geology and water resources of Big Smoky, Clayton, and 

Alkali Spring Valleys, Nevada: U. S. Geol. Survey Water-Supply Paper 

423, 1917.

39. Meinzer, O. E., Map of the Pleistocene lakes of the Basin and Range province 

and its significance: U. S. Geol. Soc. America Bull., vol. 33, pp. 541-552, 

1922.

40. Meinzer, O. E., Outline of ground-water hydrology, with definitions: U. S. 

Geol. Survey Water-Supply Paper 494, 1923.

41. Meinzer, O. E., Large springs in the United States: U. S. Geol. Survey 

Water-Supply Paper 557, 1927.

42. Meinzer, O. E., Plants as indicators of ground water: U. S. Geol. Survey 

Water-Supply Paper 577, 1927.

43. Meinzer, O. E., and Stearns, N. D., A study of ground water in the Pomperaug Basin, Connecticut, with special reference to intake and discharge: 

U. S. Geol. Survey Water-Supply Paper 597-B, 1929.

44. Reeves, Frank, Thermal springs of Virginia: Virginia Geol. Survey Bull. 36, 

1932.

45. Stearns, N. D., Stearns, H. T., and Waring, G. A., Thermal springs in the 

United States: U. S. Geol. Survey Water-Supply Paper 679-B, 1937.

46. Stearns, N. D., A remarkable intermittent spring: Mid-Pacific Magazine, 

vol. 45, pp. 217-218, 1933.
226 CONTRIBUTIONS TO HYDROLOGY, 1938-39

47. Stearns, H. T., Crandall, Lynn, and Steward, W. G., Geology and groundwater resources of the Snake River Plain, Idaho: U. S. Geol. Survey 

Water-Supply Paper 774.

48. White, W. N., A method of estimating ground-water supplies based on discharge by plants and evaporation from soil results of investigations in 

Escalante Valley, Utah: U. S. Geol. Survey Water-Supply Paper 659-A, 

1932.

UTILIZATION OF GROUND WATER

49. Austin, W. L., Irrigation of agricultural lands: U. S. Census Bur., 15th 

Census of U. S. (1930), 1932.

50. Collins, W. D., Mineral waters, including a review of the mineral-water 

trade, 1883-1923: U. S. Geol. Survey, Mineral Resources U. S., 1923, pt. 2, 

pp. 109-124, 1926.

50a. Collins, W. D., Industrial utility of public water supplies in the United 

States, 1932: Geol. Survey Water-Supply Paper 658, 1934.

51. Eastlake, G. B., Bottled water for home and office use: Industrial and Eng. 

Chem., News ed., vol. 8, no. 11, p. 2, June 10, 1930.

52. Foster, Margaret D., Chemical character of the hot springs of Arkansas 

and Virginia: Industrial and Eng. Chem., vol. 22, p. 632, June 1930.

53. Ingalls, Fay, The development of a spring property as a health and pleasure 

resort: Industrial and Eng. Chem., News ed., vol. 8, no. 10, p. 1, May 20, 

1930.

54. Meinzer, O. E., Notable improvements in ground-water development: Eng. 

News-Record, vol. 110, pp. 750-752, 1933.

55. Sale, J. W., Control of mineral waters and their salts under the Federal food 

and drug act: Industrial and Eng. Chem., vol. 22, p. 332, April 1930.

56. Thompson, D. G., and Leggette, R. M., Withdrawal of ground water on 

Long Island, New York: New York Water Power and Control Comm. 

Bull. GW-1, 1936.

SYSTEMATIC GROUND-WATER SURVEYS

57. Brown, J. S., Ground water in the New Haven area, Connecticut: U. S. Geol. 

Survey Water-Supply Paper 540, 1928.

58. Bryan, Kirk, Geology and ground-water resources of Sacramento Valley, 

California: U. S. Geol. Survey Water-Supply Paper 495, 1923.

59. Ellis, A. J., and Lee, C. H., Geology and ground waters of the western part 

of San Diego County, California: U. S. Geol. Survey Water-Supply Paper 

446, 1919.

60. Piper, A. M., Ground water in southwestern Pennsylvania: Pennsylvania 

Top. and Geol. Survey Bull. Wl, 1933.

61. Renick, B. C., Geology and ground-water resources of central and southern 

Rosebud County, Montana, with chemical analyses of the waters, by 

H. B. Riffenburg: U. S. Geol. Survey Water-Supply Paper 600, 1929.

62. Renick, B. C., Geology and ground-water resources of western Sandoval 

County, New Mexico: U. S. Geol. Survey Water-Supply Paper 620, 1931.

63. Stearns, H. T., and Vaksvik, K. N., Geology and ground-water resources of 

the Island of Oahu, Hawaii: Terr. Hawaii, Div. Hydrography, Bull. 1, 

1935. (See also Bulletins 2, 3, and 4 of the same series.)

64. Theis, C. V., Ground water in south-central Tennessee: U. S. Geol. Survey 

Water-Supply Paper 677, 1936.
GROUND WATER IN THE UNITED STATES . 227

65. Thompson, D. G., The Mohave Desert Region, California, a geographic, 

geologic, and hydrologic reconnaissance: U. S. Geol. Survey Water-Supply 

Paper 578, 1929. 

See also Nos. 4, 8, 14, 15, 20, 21, 22, 25, 26, 28, 32, 33, 37, 38, and 47.

INTENSIVE GROUND-WATER INVESTIGATIONS

66. Blaney, H. F., Taylor, C. A., and Young, A. A., Rainfall penetration and 

consumptive use of water in Santa Ana River Valley and Coastal Plain: 

California Public Works Dept., Water Resources Div., Bull. 33, 1930.

67. Blaney, H. F., Taylor, C. A., Young, A. A., and Nickle, H. G., Water losses 

i under natural conditions from wet areas in southern California: California 

Public Works Dept., Water Resources Div., Bull. 44, pp. 7-139, 1933.

68. Brown, J. S., A study of coastal ground water, with special reference to 

Connecticut: U. S. Geol. Survey Water-Supply Paper 537, 1925.

69. Eckis, Rollin, and Gross, P. L. K., South coastal basin investigation Geology 

and ground-water storage of valley fill: California Public Works Dept., 

Water Resources Div., Bull. 45, 1934.

70. Fishel, V. C., Further tests of permeability with low hydraulic gradients:

Am. Geophys. Union Trails., pp. 499-503, 1935. 

70a. Fraser, H. J., Experimental study of porosity and permeability of clastic

sediments: Jour. Geology, vol. 43, no. 8, Nov.-Dec. 1935.

70b. Graton, L. C., and Fraser, H. J., Systematic packing of spheres, with 

particular relation to porosity and permeability: Am. Assoc. Petroleum 

Geologists Bull., vol. 43, no. 8, pt. 1, Nov.-Dec. 1935.

71. Heiland, C. A., Prospecting for water with geophysical methods: Am. 

Geophys. Union Trails., pp. 574-588, 1937. See also five other papers on 

this subject in the same volume, pp. 385-409.

72. Horton, R. E., The role of infiltration in the hydrologic cycle: Am. Geophys. 

Union Trans., pp. 446-460, 1933.

73. Horton, R. E., Natural stream-channel storage: Am. Geophys. Union 

Trans., pp. 406-415, 1936. See also paper on same subject in the 1937 

transactions, pp. 440-456.

74. King, F. H., Principles and conditions of the movements of ground water: 

U. S. Geol. Survey 19th Ann. Rept., pt. 2b, pp. 59-294, 1899.

75. Lee, C. H., An intensive study of the water resources of a part of Owens 

Valley, California: U. S. Geol. Survey Water-Supply Paper 294, 1912.

76. Leggette, R. M., Wenzel, L. K., and others, Report of the Committee on 

Observation Wells, United States Geological Survey a preliminary 

manual of methods: U. S. Department of the Interior (mimeographed),

1935.

77. Livingston, Penn, and Lynch, Walter, Methods of locating salt-water leaks 

in water wells: U. S. Geol. Survey Water-Supply Paper 796-A, 1937.

78. Lohman, S. W., Geology and ground-water resources of the Elizabeth City 

area, North Carolina: U. S. Geol. Survey Water-Supply Paper 773-A,

1936.

79. McCombs, John, and Fiedler, A. G., Methods of exploring and repairing 

leaky artesian wells, with a preface by O. E. Meinzer: U. S. Geol. Survey 

Water-Supply Paper 596, pp. 1-32, 1927. The work of Sloan and Heroy 

was not mentioned in this paper because it was not at that time known 

to any of the authors.

80. Meinzer, O. E., Quantitative methods of estimating ground-water supplies: 

Geol. Soc. America Bull. 31, pp. 329-338, 1920.
228 CONTRIBUTIONS TO HYDROLOGY, 1938-39

81. Meinzer, O. E., Outline of methods for estimating ground-water supplies: 

U. S. Geol. Survey Water-Supply Paper 638-C, 1932.

82. Meinzer, O. E., Cady, R. C., Leggette, R. M., and Fishel, V. C., The channelstorage method of determining effluent seepage: Am. Geophys. Union 

Trans., pp. 415-418, 1936.

83. Mendenhall, W. C., The hydrology of San Bernardino Valley, California:

U. S. Geol. Survey Water-Supply Paper 142, 1905.

83a. Mitchelson, A. T., and Muckel, D. C., Spreading water for storage underground: U. S. Dept. Agr. Tech. Bull. 578, 1937.

84. Piper, A. M., Notes on the relation between the moisture equivalent and 

the specific retention of water-bearing materials: Am. Geophys. Union 

Trans., pp. 481-487, 1933.

85. Renick, B. C., Base exchange in ground water by silicates as illustrated in 

Montana: U. S. Geol. Survey Water-Supply Paper 520-D, 1925.

86. Riff en burg, H. B., Chemical character of ground waters of the northern 

Great Plains: U. S. Geol. Survey Water-Supply Paper 560-B, 1925.

87. Slichter, C. S., Theoretical investigation of the motion of ground waters: 

U. S. Geol. Survey 19th Ann. Rept., pt. 2c, pp. 295-384, 1899.

88. Slichter, C. S., Field measurements of the rate of movement of underground 

waters: U. S. Geol. Survey Water-Supply Paper 140, 1905.

89. Spear, W. E., An additional supply of water from Suffolk County, Long 

Island, for the City of New York, New York City Board of Water Supply, 

2 vols., 1912.

90. Stearns, H. T., Robinson, T. W., and Taylor, G. H., Geology and water 

resources of the Mokelumne area, California: U. S. Geol. Survey WaterSupply Paper 619, 1930.

91. Stearns, N. D., Laboratory tests on physical properties of water-bearing 

materials: U. S. Geol. Survey Water-Supply Paper 596-F, 1927.

92. Stiles, C. W., Crohurst, H. R., Thomson, G. E., and Stearns, N. D., Experimental bacterial and chemical pollution of wells via ground water, with a 

report on the geology and ground-water hydrology of the experimental 

area at Fort Caswell, North Carolina: II. S. Public Health Service Hygienic 

Lab. Bull. 147, 1927.

93. Theis, C. V., The relation between the lowering of the piezometric surface 

and the rate and duration of the discharge of a well using ground-water 

storage: Am. Geophys. Union Trans., pp. 519-524, 1935.

94. Thompson, D. G., Ground-water supplies in the Atlantic City region: New 

Jersey Dept. Conservation and Development Bull. 30, pp. 35-88, 1928.

95. Thompson, D. G., Symposium on fluctuations of ground-water level: Introduction, Some problems relating to fluctuations of ground-water level: 

Am. Geophys. Union Trans., pp. 337-341, 1937. This paper is followed 

in the same volume by 11 other papers of the symposium, pp. 341 391.

96. Troxell, H. C., Ground-water supply and natural losses in the valley of 

Santa Ana River between the Riverside Narrows and the Orange County 

line: California Public Works Dept., Water Resources Div., Bull. 44, 

pp. 141-172, 1933.

97. Veatch, A. C., Slichter. C. S., Bowman, Isaiah, Crosby, W. O., and Horton, 

R. E., Underground water resources of Long Island, New York: U. S. 

Geol. Survey Prof. Paper 44, 1906.

98. Veatch, A. C., Fluctuations of the water level in wells, with special reference to Long Island, New York: U. S. Geol. Survey Water-Supply Papei 

155, 1906.
GROUND WATER IN THE UNITED STATES 229

99. Wenzel, L. K., The Thiem method for determining permeability of waterbearing materials and its application to the determination of specific 

yield: U. S. Geol. Survey Water-Supply Paper 679-A, 1936. 

See also nos. 1, 6, 10, 17, 18, 29, 36, 40, 43, 48, and 63.

TEXTBOOKS

100. Baker, D. M., and Conkling, Harold, Water supply and utilization, John 

Wiley & Sons, New York, 1930.

101. Meyer, A. F., The elements of hydrology, John Wiley & Sons, New York, 

1917.

102. Muscat, Morris, The flow of homogenous fluids through porous media, 

McGraw-Hill Book Co., New York, 1937.

103. Ries, Heinrich, and Watson, T. L., Elements of engineering geology, John 

Wiley & Sons, New York, 1921.

104. Tolman, C. F., Ground waters, McGraw-Hill Book Co., New York, 1938.

APPENDIX

Geologic time divisions and the corresponding rock systems and series 

[Recognized by the Geological Survey, United States Department of the Interior]

Era Period or system

(Tertiary. _____ ______ . __ ...

iTriassic.

Devonian.

Ordovician. 

Cambrian.

Epoch or series

\Pleistocene (equivalent to "glacial").

1 0ligocene. 

[Eocene. 

/Upper (Gulf in some areas) .

(Permian.

IMississippian.

Metric equivalents 

1 inch=2.540 centimeters. 

1 foot = 0.305 meter. 

1 mile= 1.609 kilometers. 

1 acre = 0.405 hectare. 

1 square mile = 259.00 hectares. 

1 United States gallon *= 3.785 liters. 

1,000,000 United States gallons=3,785.43 cubic meters. 

1 cubic foot=28.317 liters. 

1 acre-foot= 1,233.49 cubic meters.

1 second-foot (1 cubic foot per second) = 1.699 cubic meters per minute = 2,446.58 

cubic meters per day.

INDEX

Page

Abstract___--__ _ . - - 157 

Alfalfa, relation of ground-water levels to _ _._ _ 214 

Apparatus used in ground-water investigations..._______________ 211 

Artesian conditions, abstract of... ._ -_. 158 

description of____-_ _... 175-186

in Coastal Plain __- 178-180

in Cretaceous rocks . - - 178-182 

in East-Central region..-- -----_ . 176-178

in glacial drift-.---___-----_-_- 183-184

in Great Plains region__________ 180-182 

in Paleozoic rocks_-._. - 176-178 

in Roswell Basin, New Mexico _ . 177 

inTertiary rocks.- 178-182

in valley fill-- 184-185

in Western Mountain region___ ___ 184-185 

maps showing areas of-- . 179,183 

publications on_______________ 223-225 

sections illustrating____-__._ 176,177,180,181.185

Artesian water for irrigation..-_-___--___--_ 199-201

Atlantic Coastal plain, artesian conditions in_ 178-180

ground water in___-____---------- 168-170,175

Atmospheric pressure, relation of groundwater levels to.------------------- 217

Automatic water-stage recorders, use of, 212-213

Barometric pressure, relation of ground-water

levels to._______________ 217

Capillary fringe, investigation of__ .. 207-208 

Carrizo sandstone, artesian water in______ 179-180 

Coastal plain, artesian conditions in____.. 178-180

ground water in__._________ 168-170,175 

Compression and expansion of aquifers.__ 210-211,

216-219 

Cretaceous rocks, artesian conditions in.___ 178-182

ground water in..-..-_ -- -- ._-_- 168-171

Darcy, law of____________________ 209

Discharge of ground water, abstract of._ __ 158

description of - _____, __ 186-194

investigation of_______________ 207-208

map showing relation between intake and- 188

publications on .-._____ __ 225-226

Domestic water supplies, development of_._ 196-198

Earth tides, relation of ground-water levels to. 219

East-Central region, artesian conditions in_. 176-178

rocks of-___________________ 164-168

springs in__.. __ __. _ _ _ ____ 168-194

Ebbing and flowing springs, occurrence and

features of_______ ___ __ 192-194 

Escalante Valley, Utah, fluctuations of water

levels in..______________ 214

Page

Evaporation of ground water_______________ 186-188

Geologic time divisions, table showing________ 229

Geological Survey, ground-water investigations of 160,219-221

hydrologie laboratory of_______ 204, 209-210

observation program of____._._. _ 219-22C 

Geophysical methods for ground-water investigation,________________ 212 

Geyser Spring, Wyoming___________ 192-193 

Ghyben-Herzberg law relating to salt water. __ 211 

Glacial drift, artesian conditions in_______ 183-184

map showing areas underlain by________ 169

water in.-_..--_._._- 168-169,170-171,174-175 

Graphs, of ebbing and flowing springs. _ _ _ _ _ 193

showing fluctuations of water levels in 

wells. ________________________________ 213-220

Great Plains region, artesian conditions in._ 180-182

ground water in____________________ 170-171,175

Ground-water provinces, map showing.____-. 162

Gulf Coastal plain, artesian conditions in___ 178-180

ground-water in. _ - ________ 168-170,175

Health resorts, water supplies at______. 201-202 

High Plateau, ground water in...__....__ 171

Hot springs, description of____.______ 190-192

resorts at____________________ 201-202

Hydrologie laboratory of Geological Survey,

work of. 204,209-210

Industrial water supplies_._ __.-- __._ 198-199 

Investigations of ground-water, by Geological

Survey______________ 220-221

methods and results of_____ 159-160, 202-220 

publications on 227-229

Irrigation, water supplies for_.--.___-__ 199-201

Laminar flow of ground water, law of____ 209 

Large springs, number and discharge of __. 187-190 

Literature relating to ground water, list of

representative publications.____ 223-229

summary of ____.._.__ __._ _ 222

Livestock, water supplies for..... 198

Map showing 

artesian conditions...__.___._. 179,183 

glacial drift _ - 169

ground-water provinces__..-_ .._ 162 

intake and discharge of ground water in

closed basin..__________ 188

large springs ____ 189

Paleozoic rocks______......_..__--..._-- 165

pre-Cambrian rocks..__..__.___-._ 166 

precipitation. ___._._...._____-_--______ 161

thermal springs__.._-.._-...-.-_--__._-- 191

231
232 INDEX

Map showing Continued. Page 

Triassic rocks__________..______ 167 

valley fill -...............____._ 172,188

volcanic rocks.._______.______ 173 

water supplies derived from wells__.... 195 

Methods of ground-water investigations, abstract of............._........ 159-160

description of________________ 202-220 

Metric equivalents, table of__________ 229 

Michigan, areas of artesian flow in__..-.-- 183 

Mineral water, use of________.______... 202

Molecular attraction, investigation of_-___ 205-206 

Moon, effect of, on water levels in wells. ____ 218-219

Movement of ground water, investigation of. 208-210

Norbeck, Peter, drilling methods of-------- 181-182

Observation wells, program of_ __ - __.. 219-220 

Ocean tides, relation of ground-water levels to- 219

Paleozoic rocks, artesian conditions in.--.-- 176-178 

map showing areas of. _ 165 

water in----- . ._-___- 164-167

Periodic springs-.--_____________ 192-194

Permeability, investigation of-.______- 210 

Piezometric surface, investigation of_ ... 207-208 

Plants in relation to ground water, ____- 186-188

Poiseuille law of laminar flow________.. 209

Pre-Cambrian rocks, map showing areas of-__ 166

water in.-----.---------------.--------- 167-168

Precipitation in the United States, distribution of.- -- - _- 164 

distribution of, map showing..______ 161 

relation of ground-water levels to--------- 213

Public waterworks...--__.________ 194-196 

Pumping from wells, relation of ground-water

levels to______________ 215

Quantitative methods of ground-water investigation______________.- 204-205

Recharge of ground water reservoirs. _ 206-207, 209 

Recreation, water supplies for..... __ 201-202

Rocky Mountains, ground water in------ __ 171

Roswell Basin, New Mexico, artesian conditions in______________________. 177

Salt water, contamination of fresh ground

water by___.__________ 211-212

San Joaquin Valley, California, artesian conditions in___________________ 185

San Luis Valley, Colorado, artesian conditions

in_._______----______-__-_____-_-- 185

Sections illustrating artesian conditions.... 176-185

Simpson, H. E., work of, with well drillers-_. 197 

Slichter, C. S., work of.. __________ 210 

Specific retention, investigation of---- .. 206

Specific yield, investigation of.---- ___ 206

Springs, abstract of_______________ 158

description of_____ __________ 186-194

ebbing and fiowing____-_----__-_---____ 192-194

large ... .... .. . .. 187-190

Page

Springs, periodic_______________ 192-194 

publications on _______________ 225-226 

thermal,...________________ 190-192 

Surveys of ground water, methods of making. ____-_---_.-------_.__.. 202-204

publications on______________ 226-227

Tertiary rocks, artesian conditions in___ 178-182 

ground water in..__________ 168-171,175 

Test wells for ground-water investigatons..... 211 

Textbooks relating to ground water, list of-_ 229 

Therapeutic use of water.-____ _____ 201-202 

Thermal springs, description of-_______ 190-192 

resorts at-.________________ 201-202 

Thiem, Adolph, work of _...._______ 210 

Thiem, Qunter, work of-__ _________ 210 

Tide spring, Virginia_______ _____ 192-193 

Tides, relation of ground-water levels to..--- 218-219 

Transpiration of ground water by plants, discussion of______________ 186-188 

publications on_______________ 225-226 

relation of ground-water levels to___-- 213-214 

Triassic rocks, map showing areas of-____-_ 167 

water in..__________________ 167-168

Utilization of ground water, abstract of.____ 158 

discussion of_________ .. 194-204 

publications on_. _ ___ _ _____ 226

Valley fill, artesian conditions in..__._. 184-185

ground water discharged from-.--..._ 186-187

map showing areas underlain by______ 172

water in . 171-174,175

Vegetation in relation to ground water__. 186-188

Volcanic rocks, map showing areas of- ___ _ _ 173

water in___________________ 173-174

Water-bearing formations, compression and expansion of_______ 210-211,216-218 

description of _____ .____. .... 164-174 

summary of._____ -_---_- . . 157

Water-stage recorders used in ground-water investigations-- 212-213

Water supplies from wells, for domestic use. 196-198 

for industrial use.______________ 198-199 

for irrigation _--------- 199-201

for livestock-.___..._. ........ ....... 198

for public waterworks.. .____. ____ 194-195

Water table, general relations of.____ 174,207-209

Water-table conditions, abstract of._---------- 157

description of___. .._ 174-175 

publications on__ - __ _ _ 223

Well drillers, importance of work of------- .. 197

Western Mountain region, artesian conditions

in---. . - 184-185

ground water in._.-.--________.- -- - 171-174

springs in......_... .__.. - 168-194

Willows, relation of ground-water levels to transpiration by-. -_----_______ 214

Winter Garden, Texas, artesian conditions in___ 179

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