We Running Out 

of Water?

GEOLOGICAL SURVEY 

CIRCULAR 536

V'V ^

Nrr
Are We Running Out 

of Water?

By Raymond L. Nace

GEOLOGICAL SURVEY CIRCULAR 536

Washington 7967
United States Department of the Interior

ROGERS C. B. MORTON, Secretary

Geological Survey

V. E. McKelvey, Director

First printing 1967 

Second printing 1967 

Third printing 1975

Free on application to the U.S. Geological Survey, National Center, Reston, Va. 22092
CONTENTS

Page Page

Abstract ______________________________ 1 Water resources and water

Introduction. _________________________ 1 availability Continued

World water budget___________________ 1 Water use and management _________ 5

Water resources and water availability. 4 Conclusions.-------.---------------- 6

Water use and consumption _________ 4 References ?

ILLUSTRATIONS

Page 

Figure 1. Sketch showing relative quantities of components of world water supply________ 3

TABLES

Page 

Table 1. Estimated world water supply and budget ________________________------___-- 2

III
Are We Running Out of Water? 1

By Raymond L. Nace

ABSTRACT

Water supplies are not running out, but time is getting short 

to stem waste of water and destructive exploitation of the environment before harm is done that may be irreparable. Most 

of the world's water is oceanic brine. Of the waters on the 

land, most is frozen in Antarctica and Greenland. Only a 

small part of continental water is available for use and management. The discharge of rivers to the sea is a close measure of the availability of liquid water, but ground-water reservoirs have important functions as inexpensive equalizers of 

water supply. Soil moisture is a major factor in the water 

economy, and its function usually is overlooked in assessments of water use and future water demand. Despite outcries 

of water shortage, the principal use of water in advanced 

countries is as a medium for waste disposal. In reality, despite regional maldistribution of water, United States supplies are adequate, given rational management. Also, contrary 

to common belief, water pollution is primarily a problem of 

economics, not of health. A paramount problem in most parts 

of the world is the shortage of water development and management facilities, not a shortage of water. The International 

Hydrological Decade is a program to awaken people everywhere to the crucial importance of water in man's future and 

to promote rational approach to water problems.

INTRODUCTION

"Are we running out of water?" is a question 

that is frequently asked or implied. But the 

question arises from misunderstanding, both 

of water and of water problems. When an automobile "runs out" of gasoline, the fuel hasbeen 

used up and none remains. No analogous event 

threatens water supplies. The continents are 

not running out of water, but men are fast running out of ways to avoid provision of adequate 

water works and rational management of available supplies. Societies can no longer afford profligate waste and reckless degradation 

in the quality of this supposedly renewable resource. "Renewability" loses much of its significance where usefulness of the resource 

is destroyed almost as soon as renewal oc - 

curs.

The problem of water quality and degradation of quality goes far beyond water pollution 

in relation to public health. It extends to the 

utility of water for all purposes, to national 

economics, and to national cultures. And it is 

closely related to circulation of water in the 

hydrological cycle. It is worthwhile therefore 

to consider briefly the world water budget and 

water cycle.

WORLD WATER BUDGET

The total amount of water in existence is 

about 1.36xl09 cubic kilometers (=326xl06 

cubic miles). Discouragingly enough, somewhat more than 99.4 percent of this is brine 

and ice in oceans, inland seas, glaciers, and 

polar icecaps. Table 1 summarizes some data 

about water, but it is difficult to visualize a 

billion cubic kilometers of water or a tenthousandth of one percent of a billion. Analogy 

may give a better concept of these relative 

quantities.

Let the total amount of water in existence be 

considered as one barrel about 200 liters (or 

55 gallons). (See fig. 1.) The ocean then may 

be represented as a tub containing 195 1 (50 

gal). Icecaps and glaciers would be a small 

block of ice equivalent to 4.2 1 of water (about 

1 gal). Total water participating annually in 

the hydrological cycle appears as 62 milliliters (about 2 ounces) in a small water glass. 

Annual precipitation on the land appears as 

15 ml (half an ounce) in a liqueur glass. Fresh 

water discharged annually by rivers to the sea 

shows up as about 5 ml (0.2 oz) in a small 

syringe. Annually recoverable ground water

1Based on a paper delivered orally at the First International 

Water Quality Symposium, Washington, D.C., August 25,1965.
ARE WE RUNNING OUT OF WATER?

would be represented by about a fourth of a 

milliliter (one very small drop) in a hypodermic syringe.

The total discharge of rivers is an approximate measure of potentially available and 

manageable liquid water in continental areas.

Table 1. Estimated world water supply and budget

[Modified after Nace (1960, 1964). Values in the table are approximations based on data compiled from many sources. They should not be construed to mean that any of the values is 

precise. Certain minor inconsistencies between the upper and lower parts of the table do not 

warrant adjustment for the purposes of this paper ]

Water item

Volume (thousands)

Cubic miles Cubic kilometers

Percent

of total

water

Water in land areas:

Fresh-water lakes __________________________ 30

Saline lakes and inland seas _________________ 25

Rivers (average instantaneous volume)________ .3

Soil moisture and vadose water ______________ 16

Ground water to depth of 4,000 m (about

13,100ft) __________________________ 2,000

Icecaps and glaciers ________________________ 7,000

Total in land area (rounded) ________________ 9,100

Atmosphere _________________________________ 3.1

World ocean _______ _______________________ 317,000

Total, all items (rounded) __________________ 326,000

Annual evaporation: 1

From world ocean __________________________ 85

From land areas ___________________________ 17

Total ____________________________ 102 

Annual precipitation:

On world ocean ____________________________ 78

On land areas _____________________________ 24

Total ___________________________ 102

Annual runoff to oceans from rivers

and icecaps ________________________________ 9

Ground-water outflow to oceans 2 _______________ .4

Total __ ______________ 9.4

125

104

1.25

67

8,350

29,200

37,800

13

1,320,000

1,360,000

350

70

420

320

100

420

38

1.6

39.6

0.009

.008

.0001

.005

.61 

2.14

2.8

.001

97.3

100

0.026

.005

0.031

0.024

.007

0.031

0.003

.0001

0.0031

Evaporation (420,000 km3)is a measure of total water participating annually in the 

hydrological cycle.

^Arbitrarily set equal to about 5 percent of surface runoff.
WORLD WATER BUDGET

Water in tjh« 

hydrological -cycle

Annual

oq

Discharge of . , » , >»-"*"* 

 ,"-» _ * ~ \ ,'

outflow

Figure 1. Relative quantities of components of world water supply.

The hydrological cycle has operated long 

enough in the modern climatic regime that the 

large amounts of water stored in lakes and 

underground are in quasi-equilibrium with 

water in other parts of the environment. In 

general, a lake is a delayed river a natural 

equalizer of stream flow and upstream removal of water from a lake depletes downstream flow. Natural underground reservoirs, 

the repositories of ground water, also are 

equalizing reservoirs, and they are the principal regulators of natural streamflow. This 

comparison is oversimplified, but on a continental scale it is substantially correct. 

Ground-water developments that do not deplete 

streamflow are either water-mining operations that cannot be continued indefinitely, or 

they are local salvage from evaporation and 

are insignificant on the continental scale. Like 

their surface counterparts, however, groundwater reservoirs permit use of water at different times and places and with different 

temperatures and chemical properties than 

would be possible if dependence were solely 

on natural flow in rivers and delay in lakes.
ARE WE RUNNING OUT OF WATER?

WATER RESOURCES AND WATER AVAILABILITY

A resource is a stock or reserve that can be 

drawn on when needed. Ability to "draw on 

when needed" implies that the water is available for withdrawal at the necessary time and 

place and that withdrawal is practicable. Men 

have not learned how to control precipitation 

delivery of water to the land areas so atmospheric water is not a resource in the present state of technology. Similarly, virtually 

no control of the reverse process of evaporation has been achieved. About 70 percent 

of precipitation on land areas evaporates more 

or less promptly from soil, vegetation, and 

water surfaces. Vast soil-moisture conservation projects in various countries have 

achieved control only of a minute percentage 

of evaporation and, for the world as a whole, 

evaporation control is essentially nil.

Nevertheless, soil moisture is a major factor in the water economy, and depletion of this 

water by whatever means in inhabited areas 

is a water use for human purposes. Recognition of that fact puts a perspective on total 

water use that is quite different from that to 

which we are accustomed. Land and water use 

in a region is part of the way of life of its 

inhabitants. If the inhabitants choose, for example, to retain vast areas in forest to provide timber, scenery, recreational facilities, 

and other economic and social benefits, water 

consumed by the forest is a consuming use for 

human benefit. Likewise the water consumed 

in huge areas of cropland, whether supplied by 

irrigation or by natural soil moisture, is consumed for human benefit and is part of the 

water requirement for the population.

Evidently, the water resources of any region 

consist of the percentage of total precipitation 

that can be "drawn on when needed." Soil 

moisture is available for use, at least in place, 

and alternative choices are available concerning specific uses, whether for timber, 

grassland, cropland, or other purposes. To 

the extent that use of soil moisture is subject 

to alternative choices, it is part of the resource, and soil-moisture consumption logically should be considered as a consuming use 

for human purposes.

WATER USE AND CONSUMPTION

Use of water for all purposes in the United 

States in 1960, estimated by conventional 

methods, was about 1,500 gal (5,680 1) per

capita per day according to MacKichan and 

Kammerer (1961). However, only about 23percent of the used water was consumed (turned 

to vapor), so per capita depletion of the resource was only 345 gal (1,305 1) per day.

The MacKichan-Kammerer estimates deal 

only with so-called withdrawal use of liquid 

water that is, with water diverted from surface sources or pumped from underground. 

The estimates are perfectly valid within limitations that are quite clear. But nearly all 

users of the data ignore the limitations and 

treat the estimates as though they dealt with 

total water supply and total use. From the 

planning standpoint this is plainly dangerous 

when the estimates are used as a basis for 

calculating how large a population can be supported by a given water supply without reduction in living standards.

In a realistic accounting of water resources, 

however, there is no more reason to exclude 

consumption of water by nonirrigated crops 

than to include water consumed by irrigated 

crops.

If man lived by bread alone at a bare daily 

subsistence level of 1 kilogram (2^ pounds) 

dry weight of bread, his existence would require 1,100 1 (300 gal) of water a day the 

amount consumed to grow the wheat (Bradley, 

1962). However, for a substantial advancednation diet of vegetable matter plus animal fat 

and protein, the minimum per capita water 

consumption is 9,500 1 (2,500 gal) per day, including water consumed by the living animal 

and by the plants on which it fed. This is water needed for food production only. Add water to grow cotton and wool for clothing, and 

the water demand goes up to 11,000 1 (3,000 

gal) per day about twice the per capita withdrawal of water in the United States. This is 

for a subsistence-level existence only. Add 

the other water demands of an advanced society for industry, civilized amenities, timber 

production, and many other purposes, and actual daily water use per capita rises to many 

thousands of gallons, drawn chiefly from soil 

moisture. Evidently, the total environment and 

the total water resource of a. highly developed 

area may limit the way of life and living standards of the inhabitants. The problem is not 

whether water supplies are running out, but 

whether people are outrunning the supplies. 

Water supplies have finite limits, but the demands of people on the supplies have no known 

limit.
WATER RESOURCES AND WATER AVAILABILITY

Actual outstripping of the supply is an event 

for the future, but how far in the future no one 

actually can say. Predictions that point to a 

crisis in 1980, 2000, 2050, or some other year 

have no value because they are misleading and 

therefore may be dangerous. They are merely 

straight-line projections of historical and current trends, and they seem to assume that 

withdrawal use of water will be as irrational 

in the future as it has been in the past. They 

are equally misleading and dangerous in that 

they ignore completely the nonwithdrawal use 

of water that maintains the environment and 

grows most of the food.

Turning again to conventional water-use 

data, average total water supply of the United 

States is 4.5 billion cubic meters (1.2 trillion 

gal) per day the average daily discharge of 

streams. Total water use in 1960 was about 

1 billion cu m (270 billion gal) per day about 

22 percent of the total supply. But consuming 

use of water was only about 2 30 million cu m 

(61 billion gal) per day, or about 5 percent of 

the total supply.

If the United States consumes only 5 percent 

of its water supply, how can this be squared 

with current outcries about water shortage and 

a water crisis? Several answers are available. One answer is the polluted condition of 

rivers. Out of its total potentially controllable liquid assets, the United States uses 95 

percent chiefly as a conveyor belt on which to 

send waste products out to sea. The pattern 

seems to be similar in much of Europe and 

other highly developed areas. The major use 

of free-running water in industrial nations is 

not industry, as published statistics seem to 

show, but waste disposal. So long as this condition prevails, claims that water supplies are 

running out are groundless. The fact is that a 

situation has developed in which it is essential 

to get better use of water that is actually 

available. Inequities in regional water supplies pose critical development problems for 

specific areas, but this fact only lends emphasis to the main fact that water supplies, 

nationwide in the United States, are adequate 

under adequate management.

Waterborne disease is comparatively rare 

in highly developed countries because available technology is adequate for water treatment. Water pollution in these countries is 

primarily an economic problem rather than a 

public health problem. Pollution is chiefly an

economic problem because water supplies in 

most nonarid areas are sufficient in quantity 

for present use and for greatly expanded future use. The primary concern of societies 

in these areas should be, not water quantity, 

but rational management of available supplies 

and protection of their quality. This means 

that the water bill will get bigger. Societies 

can afford this bill, but they can no longer afford to use their rivers for industrial and municipal dumps.

WATER USE AND MANAGEMENT

Present water supplies are adequate in most 

parts of the world except those that are naturally and chronically arid or semiarid. But 

adequacy of supply is no guarantee of freedom 

from problems unless management is adequate.

Water management is adequate when it correctly anticipates future problems and takes 

timely and suitable action to cope with them. 

Problems are ever changing in nature and 

scope; their solution requires flexibility and 

evolution both in planning procedures and in 

planning policy and philosophy. I shall give 

only one example of hydrological information 

that seems to call for changed procedures in 

the future.

Ground-water reservoirs in North America 

may contain 2,000 to 3,000 times as much water as is present in river channels at any one 

time. They probably contain many times more 

water than can be stored in all the surface 

reservoirs that will ever be built on the continent. North American lakes contain about 

five times the amount of water discharged annually by rivers on the continent. In short, 

nature's plumbing system has built-in regulating devices that are far larger and far more 

effective than artificial ones. Surf ace-storage 

reservoirs, viewed in proper scale; are mere 

tinkerings with details of the plumbing system. 

These details are very import ant, but they are 

still details.

Ground-water reservoirs have several advantages : Properly managed, they do not flood 

valuable lowlands; evaporation rates are very 

low to nil; they do not silt up; they do not 

wear out. Water stored in many of them can 

be augmented by artificial recharge without 

costly impoundments. Many such reservoirs 

have tremendous unused capacity. One of the
ARE WE RUNNING OUT OF WATER?

largest in the United States is the basalt aquifer of the Snake River Plain, which occupies 

an area of about 31,000 sq km (12,000 sq mi). 

A 10-meter thickness of this aquifer, assuming 

only 5-percent effective porosity, could hold 

1.6xl09 cu m(56x!09 cu ft) of water. This is 

somewhat more than a third of the annual dis - 

charge of the Snake River at King Hill (which 

is 5.3xl09 cu m per yr = 190xl09 cu ft) at the 

western edge of the aquifer. Considering that 

the basalt has 500 to 1,000 feet of unsaturated 

thickness above the water table in large areas, 

its potential for storage far exceeds the amount 

of water available for additional storage. The 

Snake River basalt and many other aquifers in 

the world in fact, all nature's underground 

regulating devices merit careful study of 

their storage capabilities. Full knowledge of 

these capabilities could well lead to more effective water-resource management than all 

potentials for manipulating streamflow by surface reservoirs. A few studies toward that 

end already are underway. New perspectives 

in water-management possibilities require 

much more concerted, unremitting exploration 

of possibilities.

CONCLUSIONS

Societies throughout the world face very real 

problems which involve water, but they are not 

primarily problems of water quantity. Rather, 

they are problems of people, of their attitudes 

toward water, and of what they do with and to 

it. For the United States as a whole, there is 

no shortage of water only a shortage of waterworks and developments. Studies in several 

European countries show similar situations 

there.

Consideration of water problems solely as 

functions of streamflow and withdrawal use is 

an evasion of the real situation. Water need 

per individual in industrial societies is nearly 

ten times greater than has been supposed, and 

the population that can be supported with acceptable living standards undoubtedly is much 

smaller than some writers have calculated on 

the basis of unrealistic assumptions.

Paramount among water problems is that of 

maintaining good water quality. Many towns 

and industries are unable or unwilling to pay 

the cost of cleaning up their own waste water. 

The attitude is, "My downstream is your upstream, and my waste is your problem." But 

in industrialized areas technology and financial means are available to maintain quality.

Only rational decision and payment of reasonable cost are required to cope with situations.

The situation is far different in the less 

developed areas of the world, comprising 75 

countries in Africa, Asia and Latin America. 

Surveys in 60 of those countries (World Health 

Organization, 1964) show that an urban population of 218,140,000 (90 percent of the total 

population) depends on water supplies that are 

inadequate or unsafe. At least 70 percent of 

the urban population relies on unpiped water 

from wells, rivers, and other sources that are 

vulnerable to contamination. There, no less 

than in the United States, the dominant shortage is of water development and waterworks, 

not of water.

In view of the universal prevalence of water 

problems, the world can ill afford to remain 

passive so long as it lacks means for fully effective management of its aggregate water 

supply. Management must assure both adequate quantity and good quality. One critical 

existing deficiency is in hydrological knowledge on a global scale. Hydrologists and 

allied scientists have taken an important specific forward step, with endorsement by many 

national governments, by proposing that 

UNESCO (United Nations Scientific, Educational and Cultural Organization) sponsor an 

IHD (International Hydrological Decade) aided 

by other international agencies and scientific 

associations. The IHD is a program on a 

worldwide scale to (1) advance knowledge of 

hydrology, especially on continental and global scales, (2) to make the benefits of water 

science more widely available and useful, alike 

to developed and developing countries, (3) to 

promote education and training in hydrology, 

and thus (4) to improve the ability of all countries to cope with their water problems.

Already 94 countries have joined the program. The United Nations, World Meteorological Organization, Food and Agriculture 

Organization, World Health Organization, and 

International Atomic Energy Organization all 

have expressed lively interest in the IHD and, 

in cooperation with UNESCO, are participating. The program started officially in January 1965. Participants have reason to hope 

that the IHD will be one of the most productive 

large international programs yet launched.

It has been said that the basic problem 

during the next 100 years will be whether man 

can learn to live with man. The water situation
REFERENCES

will have much to do with the ability of men to 

live peaceably together. No human crisis centering around water exists today, but one is 

visible on the horizon. An ultimate purpose 

of the IHD is to help forestall that crisis.

REFERENCES

Bradley, C. C., 1962, Human water needs and 

water use in America: Science, v. 138, 

p. 489-^191.

MacKichan, K. A., and Kammerer, J. C., 1961, 

Estimated use of water in the United States 

in 1960: U.S. Geol. Survey Circ. 456, 44 p.

Nace, R. L., 1960, Water management, agriculture, and ground-water supplies: U.S. 

Geol. Survey Circ. 415, 12 p.

 1964, Water of the world: Nat. History 

Mag., v. 73, p. 10-19.

World Health Organization, 1964, Community 

water supply programme: WHO Official 

Recs., no. 135, annex 10, 21 p.

it U. S. GOVERNMENT PRINTING OFFICE : 1967 O - 241-111