The
International
Hydrological
Decade
Water and man;
a world view.
~~RAYMOND L. NACE
Unesco
I’uhlished
in 1969 hy the United Nations
Educational, Scientific and Cultural Orpanization
Place de Fontenoy, 75 Paris-7”
Printed hy Irnprimeries
Oherthur
0
Unesco
lY6Y
Prinkd
in France
COM.6Y/I1.?9/A
Unesco
and its programme
In this series:
Teachers for the schools of tomorrow
by Jean Thomas
The right to education
by Louis Franqois
Children’s progress
by Richard Greenough
In partnership
with
Four statements
Preservation
youth
on the race question
of cultural
rater and man: a world
by Raymond L. Nare
heritage
view
Preface
The International
Hydrological
Decade, sponsored
by Unesco,
began on 1 January 1965 as man’s first concerted attempt to take
stock of his diminishing
available
resources of fresh water and to
co-ordinate
world-wide
research on ways of making
better use
of them.
The Decade, which began in the context
of a world water
shortage, has now reached its half-way
mark. It has mobilized
hydrologists
the world over in a task of equal urgency to developed
and developing
countries
alike. In fact, it is a task that could be
called a textbook
example
of a scientific
problem
that can be
solved only by international
co-operation.
The historical
and scientific background
of the problem and the
manner in which the machinery
of international
co-operation
has
been put into motion are the subject of thi,s booklet in the Unesco
series. The author,
Dr. Raymond
L. Nace,
and its Programme
holds the position of research hydrologist
with the Water Resources
Division
of the United States Geological
Survey. He has served as
chairman
of the United States National
Committee
for the International
Hydrological
Decade and as United States representative
on the Decade’s Co-ordinating
Council. He has worked on problems
of general hydrology
in the United States and on the disposal of
radioactive
waste.
The opinions
expressed
here are the author’s
and do not
necessarily
reflect the official views of Unesco.
Contents
Water
I
and the environment
II
Water : the substance
11
III
air conditioning
Planetary
Earth’s
The global
9
15
IV
water wheel
V
distillation
VI
Man and water through
VII
Yardsticks
16
system
17
the ages 19
30
VIII
The plight of man
34
IX
A look towards the future
36
X
A programme
for action
XI
Accomplishments
4.2
38
I
Water and
the environment
Since the dawn of civilization
increased numbers
of people and
proliferation
of their activities
have depended
on surmounting
natural
environmental
restrictions,
including
the amount
and
distribution
of water.
Water
development
and water
policies
always have been important,
as is evident from the many physical
and administrative
measures to control its distribution
and use,
beginning
with
the ancient
Sumerians
of Mesopotamia
and
becoming
ever more complex with the passage of time. Even so,
water problems are becoming increasingly
critical in many regions,
including
areas in developed
countries
where water is relatively
abundant.
The reason is that in many regions problems
are less
apt to relate to water quantity
than to its quality.
Broadly
stated,
water problems are few but basic: distribution
in space (too much
or too little) ; distribution
in time (too much in some seasons or
years and not enough in others) ; chemical
quality
(too highly
mineralized;
lacking in desirable minerals;
containing
deleterious
minerals) ; and pollution.
More will be said about these problems
in later sections. Here
it is appropriate
to note that some well-intentioned
individuals
spea,k confidently
of surmounting
all problems
by achieving
mastery of the environment.
This is an illusory
goal. Man first
must master himself. The plain fact is that he has not done so, and
because of this he has so completely
upset the natural
environmental system in which he evolved, that he no longer knows what
his place is in the system except as an element of disorder. We do
know that water has a vital role in every earth environment
from
the depths of the sea to the highest mountain;
from the dryest
desert to the wettest rain forest; and from the tropics to the polar
ice-caps. It also has a role in every activity of man and beast.
Thus far, our attempts
at ‘mastery of the environment’
have
9
Water
and the environment
been mere short-sighted
tinkerings
with the landscape. Meanwhile,
other human activity
has brought
on unwanted,
unforeseen,
and
poorly understood
side effects. Human activity
already has contaminated
the entire world ocean, the atmosphere,
and even the
remote ice caps of Greenland
and Antarctica.
Most rivers are
polluted
to some extent and many are nauseous open sewers. The
plant cover and soil fertility
of vast areas have been destroyed.
Yarts of the story of human despoliation
of the earth have been
told many times. But the whole story cannot be told because not
all of it is known and the story has not yet ended. The problem
is not mastery of the environment.
The problem is whether nature
can be preserved in some semblance of order and whether civilization can survive its own impact on nature.
The facts of history vis-&is
the plight of most of mankind
today are sufficient
evidence that the problems
of man and his
environment
are not problems
of the men of individual
nations.
They are problems
of all men and all nations. This is especially
true of water. The mobility
of water is one of its most useful
properties,
but it also gives rise to serious problems, both practical
and scientific,
international
as well as national.
It is instructive,
to consider
water
as a substance
and in global
therefore,
perspective.
10
II
Water:
the substance
Water is the only common substance that occurs naturally
and
simultaneously
in three distinct phases as gas, liquid,
and solid.
This was recognized
and emphasized
by Thales of Miletos about
2,500
years ago. Owing
to the unusualness
of this common
substance, man has cloaked water with mystery
throughout
his
history,
and much mystery
remains
even today. Each physical
and chemical property
of water was a surprise, when discovered,
and surprises continue to come. Study of water has led to many
important
discoveries about the physical world, and this is one of
the reasons why K. S. Davis and J. A. Day, in their book on water,
call it ‘The mirror
of science’. Mean sea level is the standard
reference
datum for geodesy, geophysics
and other sciences that
need a fixed datum. The freezing-point
of water is the zero point
of the Celsius temperature
scale, and its boiling-point
is the
loo-degree
mark. On the relative
density
scale of matter,
the
density of pure water is taken as unity. These are a few examples
of ways in which water is important
in science, and hence in
human affairs, far beyond its ordinary
daily uses. The story of
the growth of civilization
and science could be written largely in
terms of human concern with water.
.4 vial
of water
It is said that a small sealed vial in Paris (France)
contains
45 grams of water that was synthesized
in 1775 by burning
a gas
that later received the name of hydrogen. Nowadays, any schoolboy
can do the same thing, but two hundred
years ago chemistry
still
had made no clean break with alchemy.
The true structure
and
composition
of chemical
substances were unknown.
Even water,
the most common of palpable
substances, was a chemical mystery.
11
Water:
the substance
Antoine-Laurent
Lavoisier,
working
in his laboratory
at Paris,
the Mecca of eighteenth-century
natural
scientists, was not the
first man to synthesize
water. He was preceded by the eccentric
and misanthropic
amateur English chemist, Henry Lord Cavendish,
but Cavendish was unable to explain what had happened. Another
amateur chemist, Joseph Priestley,
the English
dissenting
ecclesiastic
and teacher,
also had observed
that some kinds
of
combustion
produced moisture. Several other experimenters
made
similar
observations
independently
and about at the same time.
None of these, however, understood
the combustion
reaction.
Lavoisier
correctly
explained
what he had achieved. In doing
so he overthrew
the old phlogiston
theory, which had led Priestley,
Cavendish
and others astray. By this and other accomplishments
Lavoisier
laid the foundations
of modern chemistry.
Atoms
of water
The atomic theory of matter is the oldest scientific
hypothesis
extant. The Greek natural
philosopher,
Democritus
of Abdera
(c. 460-350 B.C.), taught
an atomic
theory
which
had been
originated
by his mentor,
Leukippos
of Miletos.
But modern
atomic theory is a far cry from Leukippos’
idea of an invisible
and indivisible
simple mote.
The constitution
of matter
was not studied
seriously
until
2,100 years after Leukippos’
time. Late in the seventeenth
century
Robert Boyle and Isaac Newton resurrected
the concept of the
atom, though calling it a corpuscle. Boyle also drew a distinction
between chemical
elements and compounds,
and Lavoisier
later
confirmed
this in his experiments
with water and its constituents.
In 1808 John Dalton published
an atomic theory, including
the
law of constant
proportions
among the elements
in a given
compound.
That is, contrary
to traditional
belief, water has the
same proportions
of hydrogen
and oxygen whether
it falls from
the sky, flows in the Rhine, or is frozen in the heart of Antarctica.
He also conceived
the law of multiple
proportions
among given
elements in series of compounds.
That is, compounds may include
the basis
AB, AB,, AB,, etc., but not AB,g. He also established
for a system of relative atomic weights, using as unity the weight
of the lightest element, hydrogen.
His system gave wrong weights
because he assumed, as had Lavoisier,
that water is HO. In 1809
12
Water:
the substance
Joseph Louis Gay-Lussac gave a clue to the correct formula with
his observation
that bulk reactions of gases conformed
to Dalton’s
laws for atoms. Thus, two volumes of hydrogen
combine
with
one volume of oxygen.
Dalton rejected
this idea, however,
and it remained
for the
Italian,
Amedeo
Avogadro,
to straighten
matters
out with his
concept of the molecular
state of elemental
free gases. This was
published
in 1811, though not accepted until nearly fifty years
later.
Dalton’s
laws, which
really
were only astute guesses, were
confirmed
within only a few years, and the composition
of water
as H,O was firmly
established.
From
then on, advance
in
chemistry
was rapid, and water continued
to play a prominent
role. By 1895, after origination
and confirmation
of the periodic
table of the elements, devised by Dmitri Ivanovich
Mendeleev
and
published
in 1869, the atom achieved full recognition.
By 1905,
Albert Einstein had, at least on paper, smashed the unsmashable
atom.
Not until 1934, however,
did the American
chemist, Harold
Clayton Urey, show that ‘HrO’ is not the whole chemical story of
water. Urey proved the existence of heavy hydrogen
(deuterium)
and heavy water (D,O).
Then came the discovery
of heavier
hydrogen
(tritium)
and still h eavier water (T20). Oxygen also has
three isotopes. Theoretically,
therefore,
in combination
with three
isotopes of hydrogen,
eighteen subspecies of H,O are possible.
The chemical story of water in the test tube, on the other hand,
gives scarcely a hint of its importance
in the history of the earth
and its inhabitants.
14
III
Planetary
air conditioning
The importance
of water far surpasses its function
in vital organic
processes and it,s varied uses by man. Water is a key factor in the
natural
air-conditioning
system of the planet earth. Men have
often bewailed the great area and volume of the world ocean, three
times the area of the land. Actually,
these proportions
are
fortunate.
The oceans are the great heat reservoir
of the earth system,
absorbing
huge quantities
of solar energy and returning
it to the
atmosphere
slowly, maintaining
a heat regime that is acceptable
to living organisms. Much of the heat transforms water into vapour,
which becomes part of the atmosphere.
The atmosphere
absorbs
some direct and reflected solar radiation,
but not uniformly
so.
Non-uniformity
produces imbalances
in the thermal pattern of the
atmosphere
and these imbalances
cause atmospheric
motion. Solar
energy is the driving force and the atmosphere
is the vehicle that
delivers water and cool air to the land areas. Much of the water
re-evaporates
from the land, but some runs back to the sea.
15
IV
Earth’s
water wheel
The hydrological
cycle or water cycle consists of the continual
movement
of water by evaporation
from the sea into the atmosphere, by precipitation
on land and sea, and by return-flow
in
rivers to the sea. Some water precipitated
on the land re-evaporates from lakes, wet soil and vegetation;
some percolates
underground and becomes ground water; and only part of the water
returns directly
to the sea in rivers.
The atmosphere
is a very effective vehicle for water transport.
A column of the atmosphere
contains,
on the average, vapour
equivalent
to about 2.5 centimetres
of liquid water-the
thickness
of the layer of water that would form over the entire earth if all
atmospheric
water were suddenly precipitated.
Locally, however,
storm air masses may contain as much as 8 centimetres
of water
or more. The air mass involved in a hurricane
may contain in the
order of 5 to 10 cubic kilometres
of water and it may transport
this through
distances of thousands of kilometres.
Only part of
the contained water vapour is actually precipitated.
For example,
it has been estimated
that total annual vapour transport
across
the conterminous
United States is equivalent
to about 60,000 cubic
kilometres
of water, but only about one-tenth of this is precipitated.
Despite the relatively
small amount
of water in the world
atmosphere
at any given time (about 13,000 cubic kilometresj,
land areas receive large amounts of precipitation
becau,se atmospheric vapour is being continually
renewed by evaporation.
On
the average, a given molecule of water remains in the atmosphere
as vapour only about eight to ten days.
16
v
The global
distillation system
During the past decade the technology
for desalinization
of brine
and brackish
water has advanced
rapidly
and has been widely
acclaimed.
The annual world-wide
production
rate of desalinized
water is currently
in the order of 90 million
cubic metres per year.
This seems like a great deal of water until we convert
it to
0.09 cubic kilometres
and compare
it to natural
production
of
fresh water from the ,sea.
The sun, the world ocean and the world atmosphere
form a
giant natural
water distillation
plant
and distribution
system.
Solar heat evaporates
annually
about 350,000 cubic kilometres
of
water from the world ocean and 70,000 cubic kilometres
from the
continents.
The total is 420,000 cubic kilometres.
The circulating
atmosphere
distributes
the vapour around the world. An equal
amount of water falls as precipitation,
of which about 100,000 cubic
kilometres
fall on land areas. Natural
annual precipitation
on
land, therefore,
is over a million
times as great as the current
production
of artificially
freshened
water. The latter
will be
important
locally to many towns and industries,
but it is unlikely
ever to be more than a tiny fraction
of the amount produced
naturally.
Man can compete
with natural
processes only on a
local scale.
17
VI
Man and water
through the ages
The surpassing importance
of water, or lack of it, has made it a
lively topic of conversation
and action throughout
the historical
period and probably
since long before. The rising tide of human
population
in the twentieth
century has accentuated
this importance, not because water is scarce in general, but because use and
conservation
of it are poor. Throughout
the past 7,000 years men
at some time and place have been trying to increase the supply
of fresh water, or at least to increase the share used before its
inevitable
return to the sea. During most of that time the water
cycle was a mystery.
Ancient
man, like modern man, evidently
loved sunshine and
dry warm weather. But in order to prosper and multiply
in dry
areas, a change was needed more profound
than the transition
from nomadic
hunting
and herding
to sedentary
farming.
Crop
farming without irrigation
is precarious to impossible
in dry areas.
Extensive irrigation,
however, requires community
effort for water
diversion,
maintenance
of works, and allocation
of water, and
these can be achieved only through
effective social and political
organization.
Civilization
may have been a result
of man’s
unwillingness
to accept the limitations
of geography
and his search
for means to circumvent
these limitations.
Following
the ice age, climatic
conditions
identical
in all
essential aspects with those that prevail
now were established
at
least 5,OOO years ago and perhaps 8,ooO. The Near East and Middle
East already were arid to semi-arid,
and it was there that the
early civilizations
arose. This was no mere coincidence,
for the
reason noted above. Climate determined
the locale for the rise
of civilization.
19
Man and uxter
through
the ages
Irrigation
Considering
the long history of water management,
it is surprising
that the water cycle has been a mystery to man during most of his
history.
Sumerian
knowledge
about hydrology
is problematical.
Writers
of their
cuneiform
inscriptions
were concerned
with
military
exploits
and practical
matters,
rather than with intellectual adventures.
The people, however, must have had extensive
practical understanding
of running water, else they could not have
operated
a large and complicated
irrigation
system
on the
Mesopotamian
plain. They had such a system at least as early
as 4000 B.C.,and perhaps much earlier. They and their successors
held sway over a region of about 20,000 square kilometres,
and
much of this was irrigated,
though not all at the same time. The
Sumerian
irrigation
system was a marvel, not only because of its
size but also because of its long existence.
Salinity
and siltation
plagued the irrigated
fields in varying
degrees from very early
times, but the Sumerians learned to some extent to cope with the
problems. So did their Semitic successors, and irrigation
continued
until the middle of :he twelfth
century. Hulagu Khan’s invasion
in the thirteenth
century has been blamed for devastating
Mesopotamia, but the area had been essentially
abandoned
a hundred
years earlier.
Judging from experience
with modern irrigation
methods, it is
doubtful
that any modern system will last for a length of time
even approaching
that of Mesopotamia.
In the vast and fertile
Indus Plain of West Pakistan
live more than 30 million
people.
An enormous irrigation
network supplies about 9 million
hectares
of land (90,000 square kilometres).
More than 2 million
hectares
already have been lost by salinity
and waterlogging,
and current
annual losses are about 40,000 hectares.
The Indus Plain is only one example
of irrigation
problems.
Dry areas naturally
tend to have salty soil and ground water
because not enough water moves through the local water cycle to
flush salts away. Successful
irrigation
requires
application
of
sufficient
water for flushing
and sufficient
movement
of ground
water
or drainage
water
to actually
remove
the salts from
the irrigated
area. Where drainage
is inadequate,
waterlogging
aggravates
the problem.
Many tens of thousands
of hectares
annually
are lost to production
by salinity
and waterlogging,
principally
in Asia, Africa and North America.
20
Man and water
through
the ages
Organized
large-scale
irrigation
agriculture
arose in the Nile
Valley around 3400 B.C.,following
an antecedent
period of smallscale local developments.
For a variety of reasons, the problem
of
irrigation
there was far simpler
than in Mesopotamia.
Simple
flood-basin
irrigation
practice
was followed,
first on the left
bank only. Later, when basining
spread to the right bank also,
constriction
of the river by both banks raised serious problems
during high floods. During
the twelfth
Dynasty
a brilliant
plan
evolved to mitigate this problem-the
Fayum project. This project
used the Fayum depression
as an off-stream
reservoir
into which
excess waters were diverted,
forming
Lake Moeris in the desert
50 miles south-west of Cairo. During years of deficient flood water,
stored lake water was led back to the valley.
The Egyptian
irrigation
system was unique.
The irrigation
basins were lavishly
flooded, but only once each year. Sand and
gravel beneath the valley soil provided
good subsurface drainage.
There was no need for irrigation
canals or drainage
ditches, and
no general problem
arose of salinity or waterlogging
of soils. The
annual deposit of silt obviated
the need for fertilizer.
It will be
interesting
to observe the future of the Nile Valley with a modern
irrigation
system, including
a large up-stream
reservoir
where
much of the sediment will settle out of the impounded
water.
Flood
plains
and
cities
Modern
peoples are not the first to build cities on river flood
plains. Mohenjo-Daro
and Harappa,
the archaeologically
famous
cities of a civilization
that flourished
on the l.ndus Plain during
2500-1500 B.C.,got into trouble because the people did not understand or could not cope with the interactions
of land, water,
vegetation
and man in a flood-plain
environment.
The civilization
deteriorated
during a long period before it finally disappeared.
A
common supposition
has been that the Harappan
culture
was
based on irrigation
agriculture
and that it was defeated by soil
salinization.
However, some authorities
say that evidence is lacking
of any irrigation
structures in Harappan
times. A recent theory is
that the Harappan
towns were destroyed
by repeated
flooding.
Massive masonry walls around Mohenjo-Daro
failed to protect it
and it was engulfed and filled with silt. The nature of these floods
was unusual.
21
Man and water
through
the ages
A flood plain is exactly what its name implies-a
land form
built by the river during flood flows. A river is in flood when it
overtops
the banks of its channel.
Overtopping
is a normal
recurrent
event with most rivers, and minor flooding occurs every
two or three years. Higher floods are less frequent.
Indus floods
in Harappan
times, however,
seem to have been different
in
nature.
According
to one interpretation,
some unidentified
geological
event interposed
an obstruction
on the Indus River down-stream
from Mohenjo-Daro,
impounding
a lake which engulfed the town
with water and silt. After the lake’s outlet eroded the obstruction
and drained the lake, the people returned
and built anew on top
of the old masonry. This happened at least five times. A mound at
the site contains artifacts to a depth of 22.6 metres, 7.3 of which
are below the present water table and can be probed only by core
drilling.
The evidence proves that the town was engulfed by silt and
water, but whether
by a lake or by flood water remains undetermined.
The Indus Plain is very flat and a high flood would
have many of the characteristics
of a lake. At any rate, MohenjoDaro is an ancient example of a problem that has assumed major
proportions
in modern
times. Human
encroachment
on flood
plains leads to ever-increasing
damage to property
and, in some
cases, to loss of life. Modern man has not solved this problem
either, because large floods cannot be controlled.
They can only
be combated.
Other ancient irrigation
and public water works, as in Iran
and China, are equally
interesting,
but the examples
discussed
illustrate
that during many centuries classical Grecian civilization
arose, men had a great deal of practical
understanding
of water
and how to manage it. They had invented
the principal
types of
water control
structures:
diversion
dams, storage dams, shlices,
canals and drainage ditches;
they used canals for irrigation,
city
water supply
and navigation.
Their
knowledge
was largely
or
wholly
empirical,
but it was immensely
useful. Ancient
people
learned also to tap sources of ground water and to promote groundwater recharge,
but the degree of antiquity
of this knowledge
remains uncertain.
Ancient people also encountered
the same problems that beset
u.s today: maintenance
of canals and drainage
ditches;
necessity
22
_. ^
- _^ .l. .” _^-._.___,_..I,.
Man and water
thr,ough
the ages
for dredging
and disposition
of the spoil; public water supply;
navigation;
flood-fighting;
pollution.
These problems have merely
become more urgent with the passage of time and the proliferation
of the human race.
Greek
hydrology
Aside from practical
problems
of water
control,
the earliest
coherent
thinking
about water as a substance
and about the
water cycle as a whole seems to have occurred in classical Greece.
The Greek natural
philosophers
were intellectually
methodical.
They sought rational
causes for effects, rather than invoking
the
caprices of gods as basic causes. Although
mythology
strongly
influenced
their
thinking,
in principle
they rejected
myths,
substituted
rational
deductions,
and tried to reduce many facts
to a few principles.
Commonly
they were wrong but, right or
wrong, they were generally
logical.
The first of the natural
philosophers
was Thales of Miletos
(640?-546 B.C.). Knowing
the ubiquity
of water in the sea, on
land, underground
and in the air, Thales supposed
that all
substances
originally
came from water
and eventually
would
revert to that form. This may have been man’s first attempt
to
reduce the bewildering
diversity
of matter to a common denominator. Thales believed
that rivers are fed by the sea and that
wind forces water into the earth. Once inside, the weight
of
overlying
rocks forces the water upward
into the mountains,
from which it spills out to form rivers.
After Thales, the philosophers
contributed
little to ideas about
water until the time of Anaxagoras
of Clazomene
(500-428 B.C.),
a highly
original
thinker
who rejected
the Milesian
idea of a
primordial
element. He believed that no transformations
of matter
could occur and that all substances had existed from eternity.
Anaxagoras
formed
a basically
correct
concept
of the gross
hydrological
cycle: the sun raises water from the sea into the
atmosphere,
from which it falls as rain. Rain-water
gathers in
underground
reservoirs
from which the rivers flow. The earth
generates no new water, but the reservoirs
fill during the rainy
season. Perennial
streams flow from large reservoirs
and ephemeral streams from small ones.
23
Man and water
through
the ages
Democritus
developed
the atomistic
idea of Leukippos
and
taught that the properties
of substances depend on the shapes
for example,
might
be composed
of
of their
atoms. Water,
smooth spheres, which would explain
why it flows so readily.
Plato (428 or 427-348 B.C.) led a great advance
in Greek
He assumed that the universe
was created
by an
thinking.
organizing
mind and that the universe, therefore,
is understandable. The core of Plato’s water cycle, however,
was mythical
Tartarus.
He supposed
that a series of interconnecting
subterranean channels communicate
with their source, the vast reservoir
Perpetual
surging
to and fro of waters in the
of Tartarus.
subterranean
reservoir
causes the flow of springs and rivers. All
water of rivers and seas returns eventually
to Tartarus.
Aristotle
of Stagira (384-322 B.C.), pupil of Plato and tutor
to Alexander,
the son of Philip of Macedonia,
carried his thinking
far beyond that of his mentor. His vast and omnivorous
intellect
ranged the entire scope of human knowledge
and philosophy
and,
inevitably,
included
the water cycle. As ‘Will Durant has pointed
out, no scientist
can work today without
leaning
on Aristotle.
The words ‘faculty’,
‘mean’, ‘maxim’,
‘category’,
‘energy’, ‘actua‘form’ and many other abstract
lity’, ‘motive’,
‘end’, ‘principle’,
terms, were minted in the mind of Aristotle.
Peremptorily,
Aristotle
rejected the ideas of Anaxagoras
about
the water cycle and Plato’s Tartarus.
He recognized
that some
springs are fed by meteoric water, but he believed that the main
flow of water originates
in great underground
caverns where
coldness transforms
air into water. He differed with Anaxagoras
also on the explanation
of meteorological
phenomena,
such
as hail storms. Living
in an arid region, Aristotle
could not
conceive that rain was any but a minor source of water for rivers
and springs. He said that sea water turned into air under the heat
of the sun, and that air turned back into water (condensed)
in
caverns under the influence
of cold. It happens that Anaxagoras
came closer than Aristotle
to explanations
that are now generally
accepted. Aristotle,
however, marshalled
more observational
information than had Anaxagoras
and some of these facts conflicted
with the latter’s beliefs. Aristotle’s
argument,
therefore,
was the
more compelling
and it was not .successfully challenged
for nearly
2,000 years.
26
Man and water
Imperial
Rome
and
public
through
the ages
works
Before
the Romans
came under
the intellectual
influence
of
Greece they had learned
much from the Etmscans,
who were
masters in the arts of irrigation
and swamp drainage. This heritage
enabled Rome to have a well-developed
sewerage system as early
as the sixth century B.C. Romans, in general, accepted the science
of Greece and added little to basic concepts. Their great forte
as is evident from the aqueducts,
bridges and
was engineering,
other
structures
which
still
endure.
Roman
engineers
also
invented
delivery
of domestic water through pipes to households.
Curiously,
they were quite unable to measure the flow of water in
a conduit. They assumed that flow from a conduit depends only
on the size of the orifice, ignoring
the factor of hydraulic
head.
Europe
and
authoritarianism
During
the Dark and Middle
Ages many fanciful
notions were
current about the water cycle. One of these ideas, an elaborated
inheritance
from
Greece,
was that
ocean water
pours
into
submarine
caverns which conduct it to the land areas, where it
is distilled
and rises to the surface to feed springs and rivers.
The mediaevalists
were correct in that the sea is the source of
water in the hydrological
cycle, but they had the cycle turning
in the wrong direction
and they called upon the wrong distillation
apparatus.
Such ideas persisted
because
men accepted
the Greeks,
especially
Aristotle,
as final authorities,
and because of church
dogma concerning
a pa,ssage in Ecclesiastes
which was interpreted
to mean that continental
waters originate
by underground
flow
from the sea. To believe
otherwise
was heresy. Neither
the
natural
philosophers
nor the churchmen
could accept precipitation as a sufficient source for water in the land areas.
The
Renaissance
for
hydrology
Hydrology,
like other sciences and the arts, was bound eventually
to break with dogmatism
and authoritarianism.
The break came
in a curious way. The French Huguenot,
Bernard
Palissy (1514?1590), was a self-taught
ceramist
who invented
the naturalistic
27
___.____ ._-- -.- -- -.--.I_-
Man and water
masterpieces
through
the ages
of enamelled
pottery
which
he called
rustiques
The invention
saved his life. Arrested
and sent to
Bordeaux
for trial concerning
his activity
in the new religion
of the Reformation,
he seemed to be doomed. But the Queen
Mother, Catherine de Medici, intervened
by naming him inventeur
des rustiques
figulines
du roi (that is, of Henri III).
As a member
of the king’s household
he became immune
to the parliament
of Bordeaux.
Palissy boasted that he knew neither
Latin nor Greek. He
knew only what he had seen during extensive travels as a surveyor
before he took up ceramics. His observations
were acute and, in
the context
of his times, he was an accomplished
geologist,
mineralogist
and palaeontolopist.
Although
Palissy rejected theory
and relied on direct observation,
he knew enough about authoritarian doctrine
to be aware that it denied the adequacy of rain
as a source for springs
and rivers.
Nevertheless,
what
his
geological
eye saw convinced
him otherwise.
In a book published
in 1580 he declared that springs and rivers take their origin in
and are fed by rain and by rain alone. This may have been the
first such declaration
ever published.
This was more important
to mankind
than the invention
of his celebrated
enamelled
pottery,
but Palissy received no scientific
recognition
in his own
lifetime.
The world waited nearly a century
to awaken. Again,
the catalyst was a Frenchman.
In 1668, the French
amateur
scientist,
Pierre
Perrault,
convinced of the adequacy of rain as a source for run-off, set out
to prove it. During three years he measured precipitation
in the
upper Seine basin, obtaining
an average of about 49 centimetres
annually.
Calculation
showed that this was about six times the
estimated
discharge
of the Seine. He published
this and other
information
in 1674. Measurements
and calculations
such as these
could have been made at any time during the previous 2,000 years,
but science simply had not reached the stage of testing hypotheses
by measurement
and observation.
Perrault
it was, therefore,
who
initiated
modern scientific hydrology.
Perrault
correctly accounted
for the remainder
of precipitation
(the part that did not run
off in the Seine), five-sixths
of it being disposed of by groundwater recharge, evaporation,
and transpiration
by plants.
Perrault’s
findings were verified by others within
a few years
and hydrology
was launched
toward
its modern
course. The
jigulines.
Man and water through
the ages
science is interdisciplinary,
however,
and could make no great
progress
along quantitative
lines until
the basic sciences of
physics, chemistry
and biology
were well advanced,
and until
basic principles
of geology were established.
The earth’s geological
framework
is its plumbing
system, and this system must be
understood
as a basis for understanding
hydrology.
The classical
period of geology was not until the nineteenth
century.
29
_-
-
VII
Yardsticks
In scientific
and technological
work, a large share of time and
energy goes into the basic problem
of measurement.
The search
for better yardsticks
is continual.
A major reason for the tardy
development
of exact science was the early lack of means for
accurate measurement.
Advances
in the basic and derivative
sciences
gathered
momentum
during the eighteenth
and nineteenth
centuries, along
with
development
of the technology
for measuring
natural
phenomena.
The branch
of physics called hydraulics
has had
extensive
application
in hydrology.
For example,
Perrault
could
only estimate
the flow of the Seine. Nowadays,
the stages of
rivers can be gauged and recorded automatically,
while a computer
calculates
and prints out the discharge
rate. Twentieth-century
science depends heavily on ever more sophisticated
measurement
and the analysis of measurements
by computers.
Water science is handicapped
by unsatisfactory
techniques
and instruments
for measuring
many hydrological
phenomena,
especially
on the very large and very small scales. How, for
example,
does one measure
the rate of movement
of ground
water trough an aquifer
underground?
How does one measure
evaporation
from a ‘whole continent
or from the world ocean?
These cannot be measured directly.
They can only be estimated
by measuring
related phenomena
from which computed
values
can be derived.
Evaporation
and trarrspiration
are important
because they
dissipate a large .share of precipitation
on land areas. Because of
evaporation,
man-made
lakes are not unmixed
blessings. In arid
areas lakes may evaporate annually a layer of water equal to their
surface area and up te three metres or more in thickness. Evaporation plus transpiration
are usually
computed
on the basis of
30
Yardsticks
solar radiation,
wind speed, air humidity,
temperature
and other
factors. Late in the seventeenth
century,
the British
astronomer
Edmund
Halley,
based on a brief experiment
in his London
quarters,
estimated
that annual
evaporation
from
the warm
Mediterranean
sea was 3 feet (about 90 centimetres).
The estimate
was low and the modern estimate, averaged for the world ocean
as a whole, is about 100 centimetres.
Measurement
of precipitation
has been practised systematically
over an increasingly
large part of the world during nearly two
centuries.
The first European
meteorological
network
was established in 1780, with its easternmost
station in Hungary.
Europe
and part of North America
are now reasonably
well covered, but
precipitation
on vast areas in Asia, Africa, South America,
polar
regions and the seas is virtually
unknown.
Rivers
of the world
that reach the sea discharge
about
of water annually,
and this is about
30,000 cubic kilometres
30 per cent of precipitation
on the continents.
However,
only
about 50 per cent of river discharge has been actually
measured,
the rest being estimated.
The Amazon, largest river in the world,
had never been measured until 1963-64, when a joint BrazilianUnited
States expedition
aboard
a Brazilian
navy
corvette
measured it three times, once at high-water
stage, once at lowwater stage, and again at an intermediate
stage. The average flow
was found to be about 175,000 cubic metres per second, or about
5,540 cubic kilometres
per year. This is roughly
18 per cent of
the discharge
of all rivers of the world.
According
to these
measurements,
the Amazon is nearly twice as large as had been
estimated
earlier. These measurements
alone upset earlier calculations of the world water budget and illustrate
why large-scale
measurements
are important.
The last ice age ended some 10,000 years ago, but much of
the world
is still locked
in deep ice. The great ice-caps of
Greenland
and Antarctica
contain
nearly
80 per cent of all
water outside the oceans. Alpine,
Piedmont
and valley glaciers
are widespread;
shelf-ice and pack-ice cover vast expanses of the
polar seas; and permafrost
(permanently
frozen ground)
occupies
vast areas of Siberia,
northern
Europe
and northern
North
America.
The total vohrme of ice-caps and glaciers in land areas
is about 26 million
cubic kilometres,
while alI other water in
the continents
amounts to only about 8 million
cubic kilometres.
31
Yardsticks
Evidently,
much of the world is still in an ice age, but relatively
little is known about the frozen areas. The great ice-caps seem
to be stable, but considerable
difference
of opinion prevails about
whether
the ice masses are growing,
shrinking
or merely being
maintained.
It is important
that this be determined
because the
ice areas are great weather
factories
and their melting
would
cause a rise of sea level.
32
VIII
The plight
of man
The total land area of the world is I49 million
square kilometres.
About 15 million
square kilometres
is under permanent
ice cover.
Another 22 million
square kilometres
is in permafrost,
comprising
22 per cent of all the land area in the Northern
Hemisphere.
Nearly 40 million
square kilometres
is extremely
arid to arid.
Considerable
areas are high-altitude
mountain
masses. In all,
more than half the world’s
land area is basically
inhospitable
for human occupation.
Despite man’s great adaptability,
he has
made relatively
little
encroachment
in the inhospitable
areas.
Burgeoning
population,
however, inevitably
will place increasing
pressure on parts of the world that are now relatively
uninhabited
but which contain a wealth of natural resources, including
water.
These are the frontiers
of the future
and their full use will
require
pushing further
the frontiers
of knowledge
because the
new areas are poorly known and experience
in their occupation
is small.
Living
standards
in all societies are closely related to water
use. High living
standards
require
high rates of water use for
agriculture,
industry,
public services and households.
The extent
to which developing
countries can forge ahead is linked to their
ability
to develop water resources. In ,some countries
per capita
use of water is only about 100 litres per day. In some industrialized
countries water use is sixty times greater. The disparity
between
living
standards
is even larger. Lessening
of the disparity
will
require,
not only more water use, but more use per capita.
In
view of prospective
population
growth in developing
countries,
the problem
is formidable.
The developed
countries
themselves
have ,serious problems.
Doubling
of population
may entail
doubling
of water use merely to maintain
existing standards. The
situation
in the United States of America
is illustrative.
34
The plight
of man
Per capita
use of water for all purposes other than hydroelectric power generation
in the United States is about 6,100 litres
per day. This is a very high rate of use compared to that of most
even those which
are highly
industrialized.
other
countries,
However,
it is only a small part of the average total national
water supply, as is illustrated
in the table.
Total water yield (run-off)
Per capita withdrawals
Gross withdrawals
Gross consuming use
Percentage of gross withdrawals
consumed
Percentage of water yield consumed
5.4
6.1
1.2
0.3
x
x
x
x
lo*:!
lo3
101:’
101::
litres/day
litres/day
litres/day
litres/day
25
6.5
Consuming
uses are those which
turn water
to atmospheric
vapour,
so that it is not directly
reusable.
Unconsumed
water
is available
for reuse,
though
it may require
purification.
Actually,
gross withdrawal
uses, noted above, include
reuse of
some water. In some areas water is reused many times. On the
average, however, somewhat more than 90 per cent of the water
yield of the United
States is not subjected
to withdrawal
uses.
It serves as a conveyor belt to send wastes out to the sea.
While this summary
ignores recreational
and navigational
use
of water (which cannot be measured),
it helps to emphasize
the
fact that the central
problem
of water resources
development
and management
is a problem
of water
quality,
not water
quantity.
On a continental
or regional scale, water shortage in one area
may be alleviated
by interbasin
transfers of water. This will not
necessarily
alleviate
pollution,
however. In the basin from which
water is exported,
the amount remaining
to dilute pollution
is
less. In the receiving basin it may permit additional
developments
that add to the total pollution
problem.
Evidently
it is necessary to establish
national,
and in some
cases, international
objectives
and policies
to control
and abate
pollution,
not merely to control and distribute
water itself.
35
IX
A look
towards the future
Much has been written
about the population
explosion
and the
prospective
severity
of multitudes
of future problems.
The outlook is, indeed, dismaying.
However,
written
or spoken words in
themselves do nothing to cope with problems. Action is necessary.
Cope is the proper term, because problems
cannot be ‘solved’ in
any permanent
sense. All problems
involve
people so they are
problems
of water and man. The problems
cannot be ‘solved’
because numbers
and concentratione
of people
change, water
supplies
are variable
in time, and man-made
changes induce
changes in hydrological
regimes. To cope with water problems,
therefore,
requires
an endless series of decisions and actions to
meet changed situations.
Th’ is is evident from the geverity
and
multiplicity
of existing problems.
The necessity for organized
action was recognized
by scientists
many years ago, and it received
recognition
in international
scientific
circles. However,
water resources problems
as such had
no international
focus at the intergovernmental
level, so the
problem was brought to the attention
of Unesco.
In view of critical
water problems
already evident in many
parts of the world and of the disturbing
outlook for the future,
at its General
Conference,
recognized
the absolute
Unesco,
necessity for improving
the rationale
of water use and management. After several years of consideration
by intergovernmental
the Conference,
at its thirteenth
session in 1964,
meetings,
established
the International
Hydrological
Decade (IHD)
programme, starting in January 1965.
The general purpose of the IHD is to accelerate
scientific
study of water resources and water regimes in order to improve
water conservation,
management
and use. This is necessary in
all countries, developed and developing
alike. Historically,
hydro-
36
A look towards
the future
logists worked largely in obscurity.
In many countries, hydrology
was not even recognized
as a profession,
and work was done by
engineers, geologists, geographers,
climatologists,
chemists, physicists and others who were drawn into the field by chance or
necessity.
In order to accelerate
scientific
study, it is necessary
to
improve water science (hydrology)
itself and to improve education
in hydrology.
These improvements
have been consistently
stressed
in the IHD programmes
of Unesco and of Member
States.
Many scientists are motivated largely
by a thirst for knowledge.
But scientific
study and education
in science have no intrinsic
appeal either to taxpayers
or to comptrollers
of treasuries,
who
are interested primarily
in utilitarian
ends. This poses no problem
if it is recognized
that, whatever the specific motives of individual
scientists may be, the purpose of science itself is benefit to man.
Utilitarian
factors, therefore,
have always figured prominently
in
the IHD programme.
Th e prmcipal
problem
has been to gain
*
support
and attention
to long-term
broad-scale
water studies in
addition
to dealing with the short-term
immediate
problems
that
beset all nations.
Hydrological
phenomena
are related to planetary
circulations
of the atmosphere
and oceans, to the distribution
of land masses
and seas, and to major topographic
features of the land. Study
of hydrological
phenomena
therefore,
in many cases involves very
from networks
of observation
large areas. Data are needed
stations which are of suitable
density and comparable
standards
in all countries.
This requires
international
collaboration
and
mutual assistance among States.
The global distribution
of water, its mobility,
and the global
scale of the hydrological
cycle predispose
water
science to
international
co-operation.
Neither
water nor science recognizes
national
boundaries.
The effectiveness
of past and current
international
co-operation
in oceanography,
antarctic
research,
atmospheric
physics,
and other fields adequately
meteorology,
demonstrates
the benefits of international
co-operation
in science.
The IHD is taking advantage of proven methods for the advancement of science in the service of mankind.
37
-.
X
A programme
for action
Not all international
activities
require
universal
participation,
and not all consist of regional,
continental
or global studies. Any
activity
involving
two or more countries
is international.
Some
activities
within
a single country
have international
significance
and are jointly
studied
by scientists
from several countries.
Moreover,
international
exchanges of information
and ideas have
catalytic
effects, and they invariably
accelerate
scientific
understanding
of the physical
world
even without
acquisition
of
new data. They also help to show what new data will be most
useful.
The programme
for the Hydrological
Decade includes
the
following
basic components:
1. Appraisal
of the state of knowledge
of the hydrology
and water
resources of the world,
and identification
of the principal
gaps in knowledge.
This will guide new or enlarged
water
studies.
2. Standardization
of instruments,
observations,
techniques
and
terminologies
for the collection,
compilation
and reporting
of
data. This will assure comparability
of results of studies by
different
workers in different
places.
3. Establishment
of basic networks
and improvement
of existing
networks, to provide fundamental
data on hydrological
systems
varying in size from small watersheds to the world as a whole.
These data are essential for rational
water use and conservation.
4. Research
on hydrological
systems in selected
geological,
geographical,
topographical,
and climatic
environments,
constituting what may be called representative
basins. Information
obtained will have transfer value. That is, conclusions reached
38
A programme
for action
concerning
one basin may be applicable
to another
similar
basin that has not been studied.
Research
on specific hydrological
problems
whose urgency
and special nature call for a considerable
effort at international
level. An example
is the hydrology
of the Chad Basin of
northern
Africa.
Another
example
is the physical
dynamics
of the Great Lakes of North America.
Theoretical
and practical
education
and training
in hydrology
and related subjects.
Systematic
exchanges of information.
The bulk of the IHD programme
consists of activities
by participating States within
their own territories,
catalysed, co-ordinated
and supplemented
by international
intergovernmental
organizations and scientific associations. The programme
covers the entire
field of hydrology
from collection
of standard
basic data to
advanced basic research. The programme
is a challenge
to the
abilities
of individuals
at all levels of competence
in hydrology.
All nations can participate
because all have water and all have
some degree of competence.
A study by Unesco a few years ago disclosed that the world
population
of senior scientists i’s about 300,000. This is a pitifully
small minority
in terms of simple numbers-less
than 0.01 per
cent of the world
population.
Yet this group is guiding
the
scientific
revolution
in human affairs. Even more significant
is
the fact that two-thirds
of the world’s nations, containing
twothirds
of world
population,
have practically
none of these
scientists.
That is, two-thirds
of humanity
have been bystanders
in the scientific revolution.
An important
objective
of the IHD is to bring the bystanders
into action, recognizing
that no country can go far on borrowed
skill and doled assistance. Each country
must develop
its own
skill to manage its own resources.
Because of the scarcity of scientists in many countries,
some
of those countries have expressed concern about use of the term
‘scientific
hydrology’
in the programme
of the IHD. They fear
that it is an abstruse scientific
programme
in which only a few
advanced countries
can participate.
This fear is ungrounded.
Science is discovery
along the frontiers
of knowledge.
Thus
it is not new. It is as old as human curiosity.
Only ‘big science’
(lavishly
financed
science)
is new. Nations
that are only now
39
.- _---.
_---
-.
A programme
for action
emerging
from primitive
conditions
can contribute
to science,
just as they contribute
to the sum of human culture. Science is not
magic ; it is mostly hard work.
Nowadays
any minor
discovery
is apt to be heralded
as a
scientific
break-through.
But human progress is based, not only
on the supposedly
single-handed
achievements
of a few wellpublicized
individuals,
but also on the dedicated
service of
countless individuals,
unhonoured
and unrecognized,
who do the
myriad smaller tasks that make spectacular
achievements
possible.
The results and benefits of science are cumulative
and science
grows continually.
People can contribute
to science by using it
as well as by seeking new principles.
Any intelligent
and diligent
person can contribute
to science, and all nations have intelligent
and diligent
people. Therefore,
all nations can contribute
to the
programme
as well as benefit
from it. Water is the greatest
common denominator
of the earth environment
so it is intrinsically
a subject
of international
concern
and interest.
Man’s
future success on this planet may well hinge on the degree to
which
nations
joirr
hands
to co-operate
effectively
in the
conservation
and management
of water and other resources.
40
XI
Accomplishments
On the basis of hydrological
information
compiled,
projects
activated,
new data collected,
and other tangible
products,
early
within
the framework
of the IHD
were
accomplishments
unimpressive.
Although
more than one hundred
Member
States
of Unesco adhere to the IHD in principle,
less than half of these
have reported significant
activities that are actually new. However,
the real measure of progress at mid-decade
is the frame of mind
in the world community
concerning
water, the real international
co-operation
that is developing,
and the importance
of the
activities
that have been initiated
or planned.
We have space to
cite only a few examples.
One of the more remarkable
areas of South America
is the
upper basin of the Rio Paraguay-an
area called the pantanal,
which extends along the frontiers of Brazil, Bolivia and Paraguay.
This is a vast flood-plain
having an area of about 400,000 square
kilometres
and lying at an average altitude
of about 150 metres.
Its principal
physical features are thousands of small lagoons and
intervening
areas of slightly
elevated land. A study in this area,
approved
by the United
Nations
Development
Programme
(UNDP),
is being carried out by Unesco and the Brazilian
Government. Methods
of reclamation
and development,
when worked
out, will be applicable
also to the Bolivian
and Paraguayan
parts
of the basin. Expenditure
of several million
dollars for practical
and scientific
studies will make possible developments
that will
be worth many times that amount. This study is one of the world’s
greatest projects among hydrological
studies now in progress. It
is part of a long-term
co-ordinated
international
programme
of
studies for the basins of the Rio Parani
and Rio de la Plata.
A related activity
in Brazil is the establishment,
within
her
IHD programme,
of a Centre for Applied
Hydrology
at Porto
42
Accmnplishments
Alegre. This has been made possible by contributions
from the
Government
of Brazil, the National
Bank for Economic
Development, and UNDP
(Special Fund), the latter being administered
by Unesco.
The Great Lakes of North America
contain one of the largest
concentrations
of fresh surface water in the world. Canada and
the United States have collaborated
during many years in studies
of many international
water problems.
Within
the IHD, for the
first time, the two countries
are collaborating
in an intensified
co-ordinated
study of the lakes as an integrated
physical
system.
This study will have wide implications
for navigation,
power
generation,
industrial
and municipal
development,
fisheries, and
recreation.
Another
remarkable
area is the Chad Basin in Africa.
The
basin is much larger than Lake Chad itself, covering
400,000
square kilometres
and extending
into the four States of Cameroon,
Chad, Niger,
and Nigeria.
Studies in this area relate to the
soil, surface-water
and ground-water
resources. Although
many
excellent
studies had been made long before the advent of the
IHD-specifically
under
the Arid
Zone Research
Project
of
Unesco-the
IHD has made it possible to collate a wide variety
of available
data. Through
Unesco and the Food and Agriculture
Organization
(FAO),
a Commision
formed by the four riparian
States obtained
assistance from the United Nations Development
Programme
(SF). Administratively,
in consultation
with the Commission,
FA0
administers
the reclamation
studies and Unesco
administers
the general hydrological
survey. The study project
was approved in 1965 and got under way in 1966. It is an outstanding example of the intensive and extensive practical
and scientific
co-operation
that can be achieved when stimulation
and co-ordination facilities
are provided
by a programme
such as the IHD.
Still another example is Study of Ground-Water
Resources in
the Northern
Sahara, which will cover the area underlain
by
principal
artesian aquifers
in Algeria
and the Saharan area of
The study is in progress
under the auspices of the
Tunisia.
governments
of the two States, under an agreement
with UNDP,
with Unesco serving
as the United
Nations
Participating
and
Here also, the purpose
is to organize
and
Executing
Agency.
amplify
scientific
and practical
information
as a prelude
to
rational
use of the resources.
43
Accomplishments
Quite a different
type of project
is the establishment
of a
Centre for Hydraulics
and Applied
Hydrological
Research
at
Ezeiza, Argentina.
This also will be assisted by UNDP (SF), with
Unesco as the Participating
and Executing
Agency. The over-all
purpose is to build up within the state, facilities
and capabilities
for advanced studies and research in water science and application
of the results to practical
development
projects.
A similar establishment
with a similar purpose is the lnstitute
for Hydrosciences
and Water Resources Technology,
in Iran. This
has been established
by the Government
of Iran, assisted by
UNDP (SF), with Unesco as the executing
agency.
A considerable
number
of similar
and varied activities
may
be cited: Co-ordinated
planning
of IHD activities
by the council
of the five Nordic countries;
research on uses of saline water for
irrigation
in Tunisia;
world-wide
research on the uses of radionuclides
in hydrology
(leadership
by the International
Atomic
Energy Agency
(IAEA))
; th e interstate integrated
hydrometeorological study of Lake Victoria,
administered
by the World Meteorological
Organization
(WMO) ; development
of the Central
American
hydrometeorological
network,
administered
by WMO ;
development
of a flood-warning
system for the Mekong
River
Basin ; establishment
of a Natural
Resources Institute
in Iraq;
and many other activities.
Study of the many documents
produced
by the IHD
Coordinating
Council
and of its Working
Groups and Panels of
Experts,
perusal
of reports
submitted
by Member
States in
response to questionnaires
from the Secretariat,
and direct contact
with scientist’s from Member States, all indicate a new awareness
of the importance
of hydrology.
Only a few years ago, many
hydrologists
and government
officials
were complacent
about
water resources
and problems.
The Decade has created
new
awareness among the nations of the world that water problems
are large and growing. Decade activities
have exposed the glaring
inadequacy
of information
about water in many parts of the
world and the depressingly
retarded
state of some aspects of
hydrology,
the only science that can translate
raw data into
water information
that can guide action to conserve and use
water.
Developing
countries
are rightly
anxious to see construction
machinery
in action on water-development
projects. International
44
Accomplishments
organizations
that provide
project
funds also want to see dirt
fly. Planning
studies
have generally
been heavily
weighted
toward
engineering
and economic
feasibility
and minimally
toward hydrological
or ecological
aspects. Possible unwanted
side
effects have received little attention.
Consequently,
some projects
have been over-designed,
under-designed
or wrongly
designed.
Over-design
entails excessive costs for construction.
Under-design
results in failure
to achieve maximum
use of resources. Wrong
design can cause either or both results, and it may lead to project
failure.
Circumstances
are now changing
and scientific
studies are
being authorized
and carried
out in advance of crystallization
of plans and beginning
of construction.
An example,
already
mentioned,
is the organized
international
study of the La Plata
River basin in South America,
involving
five nations
and one
of the world’s great rivers. Advance studies can save many millions
of dollars of construction
cost and greatly improve
the benefit/
cost radio of projects.
The industrialized
countries
have extensive
networks
for the
accumulation
of basic water data. Special compilations
of these
data for the IHD have disclosed an over-supply
of some kinds
of data and a serious shortage of other kinds. These countries
are modifying
their observation
programmes
accordingly.
Developing
countries,
on the other hand, have recognized
the
necessity for cultivating
their own hydrological
competence
and
establishing
observation
networks.
Their small cadres of hydrologists have always recognized
these needs, but the General
Conference
of Unesco, by establishment
of the IHD, brought
the
matter
to the attention
of governments
at ministerial
level,
including
ministers
of finance.
With
nations,
as with
individuals,
the first step toward
improvement
is recognition
and acknowledgement
of deficiencies.
The second is determination
to correct
them. The spirit
of
determination
is visibly growing throughout
the world.
Education
and training
have always
had a high-priority
position
in the IHD programme.
For two years preceding
the
a modest
head-start
programme
of
IHD,
Unesco
sponsored
education
in hydrology.
During the Decade, various governments
and universities,
with the collaboration
and assistance of Unesco,
have established
advanced-level
semester-length
special courses
45
Accomplishments
in hydrology
and water resources problems.
Such courses have
been established
in Czechoslovakia,
Hungary,
Israel,
Italy,
Netherlands,
Spain
and Venezuela.
These
are for foreign
nationals.
In addition,
Unesco, WMO and FAO, in collaboration
with other organizations
and universities,
have sponsored many
seminar-type
short courses in hydrology,
chiefly in countries
of
Latin America
and North Africa.
Further,
various universities
in developed
countries have offered many scholarships
to foreign
nationals
to enable them to enrol in regular university
curricula
oriented
toward hydrology.
It is not practical
to include here a full report of progress
on all IHD activities.
These will be covered more fully in other
reports
to the Intergovernmental
Conference
on the IHD
in
October
1969. Suffice it now to say that the role of water in
international
affairs, as well as in the well-being
of man and the
fate of his environment,
is now more widely recognized
than ever
before. This recognition
is growing,
and hydrology
is on the
move. Thus, the IHD is gaining its proper role among the many
international
co-operative
programmes
that are aimed to improve
the lot of all men at all places.
46