(PDF) Water - A Key Driving Force

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Introduction

Water is the most valuable resource on the earth and

an integral part of the environment. Its availability is

indispensable to the efficient functioning of the biosphere.

Settlement of most of the great ancient civilizations has been

generally associated with a reliable and clean supply of water

with convenient sources. For example, the Egyptians centered

their civilization on the Nile. Mesopotamia (the land between

the Tigris and the Euphrates rivers) was the home of several

important ancient empires. Chinese civilization was located

principally in the Yellow and Yangzi river basins. Since the

dawn of Indian civilization, the Ramayana, Mahabharata, the

Arthashastra by Chanakya (3rd century BC), Puranas, the Vrahat

Samhita (550 A.D), the Meghmala (900 AD), Panini’s Astadhyayi

and various other Vedic, Buddhist and Jain texts contain several

references to the various processes of hydrological cycle and

traditional water harvesting structures and water being revered

as a life giving and sustaining force. The bible quotes, ‘I am

the Alpha and the Omega, the beginning and the end. To the

thirsty I will give water without price’ - Revelation 21:6. In

Islam, the Sharia law in Koran literally translates to laws of

sharing water. Water facilitated relatively rapid transportation

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prior to about 1850 C.E. From the late 15th through the 18th

centuries, Europeans explored all the major oceans.

Besides earth, there are evidences of water in a variety

of places in the Universe including: the Moon, Mars, Jupiter’s

moons, comets, and in interstellar clouds. Yet, until today,

it is not clear why there is more water on the Earth than on

the other planets of the solar system. Except for fossil water,

all water on the planet Earth circulates throughout the

atmosphere, geosphere and hydrosphere. Amazingly, less

than 1% of the earth’s water is available for human

consumption. Almost one-quarter of the world population

lacks a safe supply of water and half the population lacks

adequate sanitation. Over 90% of the world’s developing

countries, located in arid and semi-arid areas, are under

higher water stress. Over 50% of the world’s population is

estimated to be residing in urban areas, and almost 50% of

the mega-cities having populations over 10 million are

heavily dependent on groundwater, and all are in the

developing world. Nearly 40% of global food production is

attributed to irrigated abstraction, and 70% of the world

groundwater withdrawals are used for irrigation purposes.

Safe and stable water supply is of vital importance to all

socio-economic sectors development. Water has always been

an important source of power, and remained an essential

component in all kinds of manufacturing processes and one of

the most important components of sustainable development.

It is essential for natural habitat – for drinking, cleaning,

agriculture, transportation, industry, recreation, animal

husbandry, and providing electricity for domestic, industrial

and commercial use. On the other hand, extreme events of more

or less water may have an impact not only on the human society

but also on the aquatic and terrestrial environments. Expanding

human activities have greatly impacted the water cycle,

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resulting in growing number of global water problems and life-

threatening hazards. Misuses of water resources and poor water

management practices have often resulted in depleted supplies.

Most of the people take water for granted. For many, water

becomes an important factor until one turns on a faucet or

flushes a toilet and don’t find flow of water. Conflicts over

water have become more common among competing water

users.

In recent times, due to increase in population,

urbanization, industrialization and use of chemicals in

agriculture, there is an ever-increasing threat to the quality of

water resource base, resulting in decrease in fresh water

availability. While this crisis is most pronounced in the

developing countries, the developed world and economies in

transition also experience major environmental problems and

human health consequences. The problems also include water

shortages due to imbalances between water demand and

supply, and ecosystem deterioration, caused by improper land

use. Erosion and sedimentation, floods induced by

urbanization, the problem of fresh and salt water interaction

both in the surface water and in the groundwater environment.

The humid tropics and temperate zones, while normally

associated with less dramatic hydrological phenomena than

the arid zones, still remain in the focus of interest. Apart from

these, water resources management problems exist in the fragile

ecosystem of dry lands, wetlands, mountains, coastal zones

and small islands, irrespective of their geographic/climatic

location and land use such as urban, peri-urban and rural areas.

While the urban clusters look for low to moderate

volumes of high-quality water, rural clusters look for large

quantity of high-quality water, in inefficient field distribution

and drainage systems. In many areas of India, due rise in water

demand for irrigation and other purposes, inadequate

Introduction

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availability of surface water supply, groundwater will continue

to be used intensively. Farmers adopt groundwater irrigation

due to apparent reliability of storage offered by mechanized

drilling and pumping, and flexibility of groundwater

exploitation, but remain indifferent about quality unless the

groundwater is saline. Increasing indiscriminate groundwater

use has crossed the sustainable limits. In different parts,

environmental problems are evident, such as; lowering in

groundwater levels, decline in productivity of wells, more

seepage from canals, increasing trend of salinity and

groundwater pollution, intermixing of contaminated water

with fresh water, etc. The problem is also compounded by the

complexities of the interactions among the physical,

hydrological, meteorological and biological environment,

management of the natural and the socioeconomic systems.

Increasing water use and pollution generation has crossed

the sustainable limits in many parts. The story of each region

or city may be different, but the main reasons for the water

crisis are common, such as, increasing demand, zonal disparity

in distribution of water supply, lack of ethical framework,

inadequate knowledge and resources. Thus, the issue of water

Agricultural use Industrial use Domestic use

High income

countries

Low-and Middle-

income countries

World

8% 8% 11%

59%

30%

10%

82%

22%

70%

Water use worldwide

What if developing countries follow their developed counterparts

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management is multidimensional, related to reliable

assessment of available water, its supply and scope for

augmentation, distribution, reuse/recycling, its existing

depletion, degradation, pollution and its protection from

depletion and degradation. However, like surface water

resource management, not much concerted efforts have been

made for management of the hidden underground water

resources. Water supply schemes, generating large amounts

of wastewater, are normally designed and built, without the

required matching drainage networks and wastewater

treatment facilities. So far, water has been managed in a

fragmented way. This fragmentation of approach also impedes

coherent hydrological analyses at regional, continental and

global scales. The incorporation of the social dimension

underlines the need for improved, more efficient management

of water resources and the more accurate knowledge of the

hydrological cycle for better water resources assessment.

Since the latter half of the 20th century, rapid population

growth and expanding human activities have given rise to a

variety of serious water problems at the global, regional, and

local levels. The expression, “the 21st century will be an age of

water,” embodies both the concern that water issues may cause

international conflicts and the hope that these same issues will

promote international cooperation. The growing concern for

the water sector have been echoed repeatedly at several

international forum beginning with the UN conference on the

Human Environment, Stockholm in 1972 to the 3rd World

Water Forum, Kyoto in 2003. United Nations declared the year

2003 as the International Year of Fresh Water. The UN General

Assembly at its 58th session in December 2003 agreed to

proclaim the years 2005 to 2015 as the International Decade for

Action, “Water for Life”, and beginning with World Water Day

- March 22, 2005. To solve the aforesaid water problems,

science-based research efforts must be promoted to clarify the

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structural relationship between the water cycle and human

activities, as well as establish a sound and sustainable

relationship between them.

The increasing worldwide pressure on water resources

under anthropogenic and environmental change requires an

integrated multidisciplinary approach to address issues

involving water resources assessment and management; taking

a holistic view of the water resources, considering issues, such

as, the quantity and quality of surface water and groundwater

and their interdependence, freshwater and saltwater interface,

urban growth and changing land use patterns, as well as risks

and hazards of flood and drought; identifying the pertinent

parameters, phenomena, processes and possible changes of the

hydrological cycle, and evaluating the water requirement of

different development alternatives; simultaneously addressing

science and policy, based on reliable physical and socio-

economic information. Enhancement in water availability and

safe water supply will be guided by the policies, plans and

technologies at our disposal, in addition to political, socio-

economical, biological and other factors. Choices based on the

best obtainable detailed scientific information, guided by ethical

considerations, offer the best hope to protect water from

depletion and pollution.

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Basic Information

To have further insight on the origin of water in the

universe and on the earth, let us discuss the origin of the

elements hydrogen and oxygen that make up water molecules.

The Big Bang: 10 to 20 billion years ago, the Universe was

in an extremely dense and hot (~10 billion °C !) state that

exploded in what is called ‘The Big Bang’. Eventually, the

Universe expanded and cooled and huge collections of gas

formed into billions of separate galaxies, and billions of stars

formed within each. Many fundamental particles were formed

in the beginning of this process, including the basic building

blocks of all atoms: protons, neutrons, and electrons. The two

lightest elements, hydrogen and helium, were also formed.

Some heavier elements were created in the Big Bang, but only

in very trace amounts, e.g., one lithium atom out of every 10

billion atoms. So how are the heavier elements, such as oxygen,

formed?

Stellar Evolution: Stars, which contain mostly hydrogen,

like Sun produce huge amounts of energy from nuclear fusion

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in their hot cores. The pressure and temperature is so great in

the core that hydrogen is fused together to form helium. 90 per

cent of a star’s lifetime is spent fusing hydrogen into helium.

Once the hydrogen is used up, helium begins fusing and one

of the by products of that process is oxygen. Depending on the

mass of the star, all the heavy elements up to iron can be created

in succeeding fusion reactions or nucleosynthesis. Due to the

Big Bang created hydrogen and oxygen by nucleosynthesis in

stars, and the fact that these elements are highly reactive

chemically, water should therefore be fairly common in the

Universe. However, only at certain temperatures and pressure,

like those found on Earth, liquid water is expected to be found.

Detecting Water Beyond the Earth

Detecting water in the Universe up to now has been done

almost entirely remotely. The composition of a planet’s

atmosphere and surface can be partially determined by

analyzing the spectrum (a displa y of the intensity o f li ght emitted

at each wavelength) of light emitted or absorbed by the

elements that compose it. A spectroscope splits the light into

its components, like a prism, which shows the different colors

(wavelengths) making up white light. Atoms of a given element

can emit only light of specific wavelengths. Similarly, each type

of molecules has a unique spectrum of light. Thus, if the

spectrum of water is found to be present in the full spectrum

of light that is observed from a given planet, the existence of

water on that planet can be inferred. Water molecules have

been detected in this manner in the atmospheres and the

surfaces of some of the planets. In the last few years, planetary

probes have detected tantalizing evidence that water may exist

on other bodies in our solar system, though in fact no other

planet or moon in our solar system has the amount of liquid

water present on the earth. Specifically, the following is a partial

list of evidence of the existence of water in the universe,

detected spectroscopically and by other means:

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Ice on the Moon: Over the last couple of years, spacecraft

orbiting the Moon has indicated the possibilities of a large

amount of subsurface ice there.

Comets: Comets (sometimes referred to as “dirty

snowballs”) are chunks of dust and frozen gases including

water that are in highly oblong orbits around the Sun. As

they near the Sun, the sunlight melts some of the comet’s

material, which results in a long tail.

Mars: Th e spacecraft p hot ogr aphs of the Pla net sho w long

jagged structures that appear to be old rivers and canyons.

Photographs taken recently show stacked boulders,

probably deposited by raging floods. However, the

atmospheric pressure on Mars is now 100 times less than

that of earth, and therefore, water cannot exist as a liquid

there anymore, and possibly much of the water exists as

subsurface ice. There are polar ice caps (composed of

frozen carbon dioxide, but small amounts of water-ice)

that get larger during the Martian winter and smaller in

the summer.

Europa: The Galileo spacecraft orbiting Jupiter has

photographed he surface of one of its moons, Europa,

which appears cracked with many fissures, as if it is made

of ice that freezes and then thaws repeatedly.

Interstellar Clouds: The spectrum of water has been

detected in interstellar gas/dust clouds. Water molecules

in masers in interstellar clouds are stimulated by the

energies of nearby stars.

The Origin of Water on Earth

The earth appears to be unique in the solar system in the sense

that it contains an enormous amount of water, which has

existed in more or less in its present state for billions of years.

To know the reason for this, it is necessary to understand the

processes that governed the formation of the earth and the

evolution of the earth and its atmosphere. According to the

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most recent theories of planet formation, two steps govern the

process of planet formation: (i) Gravitational collapse takes

place forming small asteroid like bodies, some as large as 1/

500 of the mass of the earth. The planetesimals begin to collide

and form the larger bodies of the planets; and (ii) when a meteor

hits anything, some of it sticks and some is scattered back into

space by the impact. The lower the density of the material, the

more likely it is to escape. In the early stages, the earth collected

heavier stuff more easily, leaving lighter stuff such as silicon

and water still in orbit about the sun. However, it more

effectively trapped the lighter material during the latter stages

of planet formation.

The formation of the earth probably took a few hundred

million years to be completed, as compared with the time of

about 3.5 billion years since the earth has developed a solid

crust. About the time the earth was formed, the sun became

large enough that the fusion reactions in the sun ignited. This

didn’t happen smoothly, but likely in sputtering way for a

while. Each flaring up of the sun sent streams of particles

sweeping out. If the earth had an atmosphere at this time, it

would have been blown off leaving the earth as a rock with

neither air nor water on its surface. In fact, after the sun

stabilized, the earth went through a process of releasing gases

from its interior in a process called degassing. Over a relatively

short time, around 100 million years, enough material had been

released to form the oceans and to give the earth an atmosphere.

There was no free oxygen in the atmosphere at this time, but it

was a collection of gases, largely ammonia, methane and carbon

dioxide, held to the earth by gravitational attraction.

Fortunately, early in its history, the temperature of the earth

dropped below 212 degrees Fahrenheit, and the water

condensed into the ocean that exists today.

In fact, the mass of water present in the oceans now (about

1024 grams), is about the same as the mass of water that was

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contained in the crust when the degassing process started only

a few hundred million years ago. The rate at which water is

being lost today can be estimated by calculating the rate at

which water molecules in the atmosphere are dissociated into

its constituent hydrogen and oxygen. The hydrogen being light

enough easily moves off into space. The net effect of hydrogen

loss decreases the amount of water vapor in the atmosphere.

A good estimate is that 5x1011 grams are lost this way each

year. This amounts to a volume of a cube about 100 yards on a

side. The total water lost to space since the beginning of the

earth thus amounts to about 2x1021 grams, about 0.2 percent of

the water in the oceans. Fortunately, the same geologic

processes that formed the oceans originally replace the water

lost to space.

Why is the water still here on the earth? It has to do

with the changing nature of the atmosphere due to evolution

of life, specifically algae. The algae produced free oxygen

by photosynthesis, which destroyed ammonia and methane,

so called greenhouse gases, just as the sun’s luminosity was

increasing by about twenty five percent. If that hadn’t

happened the oceans would have boiled away long ago. In

fact, human beings are the beneficiaries of an incredible

balancing act, which allowed just enough heat to escape from

the earth to keep the oceans from boiling, but not so much

as to cause the earth to freeze solid. Some of the popular

theories pointing towards most likely contributing factors

to the origin of the Earth’s oceans over the past 4.6 billion

years are as follows:

1. The cooling of hot gases were released causing “out

gassing”, potentially bringing water to Earth.

2. Comets, trans-Neptunian objects or water-rich asteroids

from the outer reaches of the asteroid belt colliding with

a pre-historic Earth may have brought water to the world’s

oceans. Measurements of the ratio of the Hydrogen

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isotopes Deuterium and Hydrogen-1 point to asteroids,

since similar percentage impurities in carbon-rich

chondrites were found to oceanic water, whereas previous

measurement of the isotopes’ concentrations in comets

and trans-Neptunian objects correspond only slightly to

water on the earth.

3. Liquid may have been “locked” in the Earth’s rocks and

leaked out over millions of years.

4. Photolysis. (Radiation can break down chemical bonds

separating liquid from hard mass)

5. Rain and sandstorms may have pooled.

It is quite likely that more than one of these factors

contributed to the vast oceans, covering the Earth’s surface at

the present time. The present coastlines are where they are

because some of the water is locked up in the polar ice caps.

With this introduction to the origins of our planet, let us now

turn to consider how the water exists in/on the earth.

Rain: A valuable resource

Rain and snow are key elements in the Earth’s water cycle,

which is vital to all life on Earth. Rainfall is the main way

through which the water in the clouds comes down to Earth,

where it fills the lakes and rivers, recharges the underground

aquifers, and provides drinks to plants and animals. Rain

does not fall in the same amounts throughout the world or

even in different parts of India. What happens to the rain

after it falls depends on following factors:

The rate of rainfall - A lot of rain in a short period tends

to run off the land into streams rather than soak into the

ground.

The topography of the land - Water falling on the land,

hills, valleys, mountains, and canyons drains down and

becomes part of a stream, a lake, or groundwater.

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Soil conditions - Dense clay soil makes rain a hard time

soaking into, contrast to the sandy soils in desert areas,

which allow water to be quickly absorbed.

Density of vegetation - Land with plant cover slows the

speed of the water flowing on it and thus helps to keep

soil from eroding.

Amount of urbanization - Ro ads, pavement , an d pa rki ng

lots create impervious areas where water can no longer

seep into the ground, causing runoff water.

Where is Earth’s water located?

About 70 and 75% of the Earth’s surface is water-covered. But

water also exists in the air as water vapor and in the ground as

soil moisture and in aquifers. The same water that existed on

Earth millions of years ago still exists, but, is always in

movement, and the water cycle, also known as the hydrologic

cycle, describes the continuous movement of water on, above,

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and below the surface of the Earth. Water can change states

among liquid, vapor, and ice at various places in the water

cycle, over millions of years. Things would get pretty stale

without the water cycle!

When the water around is looked at, water in streams,

rivers, and lakes is seen, which is known as “surface water.”

However, there is much more water stored under the ground

than on the surface. In fact, some of the water seen flowing in

rivers comes from seepage of ground water into river beds.

Water from precipitation continually seeps into the ground to

recharge the aquifers, while at the same time water from

underground aquifers continually recharges rivers through

seepage. The water in the apple eaten yesterday may have fallen

as rain half-way around the world last year or could have been

used 100 million years ago by Dinosaur to give her baby a bath.

About 97% of all Earth’s water is in the oceans. The

balance 3% is freshwater. The majority, about 69%, is locked

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up in glaciers and icecaps, mainly in Greenland and Antarctica.

It may be surprising to know that almost all of the remaining

freshwater is below the land surface, as ground water. Of all

the freshwater on Earth, only about 0.3 percent is contained in

rivers and lakes — yet rivers and lakes are not only the most

familiar water, but also the water which is mostly used in

everyday lives.

How much water is there on/in the Earth?

In terms of volume, according to the available estimates, the

water on earth is distributed as follows:

1.35 x1017 cubic meters (97.3%) Oceans

29x1015 cubic meters (2.1%) polar ice and glaciers

8.4x1015 cubic me ter s (0 .6 % ) un der ground aquife rs ( fre sh)

0.2x1015 cubic meters (0.01%) lakes and rivers

0.013x1015 cubic meters (0.001%) atmosphere (water

vapor)

0.0006x1015 cubic meters (0.00004%) biosphere.

The role of individual components in Earth’s water

turnover depends both on the value of water storage and its

dynamics. Hydrospheric water of different kinds is fully

replenished during this period in the process of hydrological

cycle. Its value varies in a very large range. In hydrology and

water management, based on water exchange characteristics,

the two concepts are often used to assess water resources in a

region: the static, or secular, freshwater storage and renewable

water resources. The static, or secular, storage includes

conventionally the freshwater with the period of full renewal

of many years or decades (large lakes, groundwater, glaciers,

etc.). The renewable water resources include the water yearly

replenished in the process of water turnover on the earth. It is

mainly the river runoff estimated in the volume referred to a

unit of time (m3/s, km3/year, etc.) and formed in the region or

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An estimate of global water distribution

Water source Water volume, Water volume, Percent of Percent

in cubic miles in cubic freshwater oftotal water

kilometers

Oceans, Seas, & Bays 321,000,000 1,338,000,000 — 96.5

Ice caps, Glaciers, & Permanent Snow 5,773,000 24,064,000 68.7 1.74

Ground water 5,614,000 23,400,000 — 1.7

Fresh 2,526,000 10,530,000 30.1 0.76

Saline 3,088,000 12,870,000 — 0.94

Soil Moisture 3,959 16,500 0.05 0.001

Ground Ice & Permafrost 71,970 300,000 0.86 0.022

Lakes 42,320 176,400 — 0.013

Fresh 21,830 91,000 0.26 0.007

Saline 20,490 85,400 — 0.006

Atmosphere 3,095 12,900 0.04 0.001

Swamp Water 2,752 11,470 0.03 0.0008

Rivers 509 2,120 0.006 0.0002

Biological Water 269 1,120 0.003 0.0001

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incoming from outside, including the groundwater inflow to

the river network. This kind of water resources includes also

the yearly renewable upper aquifer groundwater not drained

by the river systems.

What is river?

A river is surface water flowing over land, due to gravity, from

a higher altitude to a lower altitude. When rain falls on the

land, it either seeps into the ground or becomes runoff, which

flows downhill initially as small creeks, which merge to form

larger streams and rivers, eventually end up flowing into the

oceans. When water flows to a place surrounded by higher

land on all sides, a lake is formed. If a dam is built to check a

river’s flow, a reservoir is formed. In the process of turnover,

the river runoff is not only recharged quantitatively, but its

quality is also restored. So the river runoff, actually represent

the renewable water resources. River water is of great

importance in the global hydrological cycle and supply of fresh

water. River runoff is most widely distributed over the territory

and provides the major volume of water consumption in the

world. In practice, the water availability is assessed by the

estimation of river runoff.

Length of Some Important Rivers

Nile (Africa) : 4,132 miles

Amazon (South America) : 4,087 miles

Yangtze (Asia) : 3,915 miles

Huang He, aka Yellow (Asia) : 3,395 miles

Brahmaputra (India) : 1,800 miles

Indus (India) : 1,800 miles

(Source: http://www.nps.gov/rivers/waterfacts.html, accessed on 9th

October, 2006)

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Dynamics of water use (Source: www.unesco.org/courier/2001_10/uk/

doss02.htm)

World Water Use

The agricultural sector is the largest user of water globally

and accounts for about 70% of the total freshwater

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abstraction. Presently, industry accounts for 22% of the

global freshwater consumption.

However, water consumption by industries is increasing,

and likely to double over the next two decades. In fact, in high-

income countries, industrial water use already accounts for as

much as 59% of the total fresh water consumption. The volume

of water consumed per year by industry is estimated to be 1,170

km3/year by 2025. People, especially in rural areas, are

increasingly dependent on groundwater – up to 2 billion

people, a third of the world’s population rely on it.

The left-side pie chart shows that over 99 percent of all

water (oceans, seas, ice, and atmosphere) is not available for

our uses. And even of the remaining 0.3 percent (the small

brown slice in the top pie chart), much of that is out of reach.

Considering that most of the water that is used in everyday

life comes from rivers (the small light blue slice in the right-

side pie chart), generally, it is only a tiny portion of the available

Notice of the world’s total water supply of about 1,386 million

cubic kilometers, over 96 percent is saline.

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water. The right-side pie shows that the vast majority of the

fresh water available for our uses is stored in the ground (the

large brown slice in the second pie chart).

World Water Turnover

Every year the water turnover on Earth involves 577,000 km3

of water. It is the water that evaporates from the oceanic surface

(502,800 km3) and from land (74,200 km3). The same water

amount falls as atmospheric precipitation (on the ocean 458,000

km3 and on land 119,000 km3). The difference between

precipitation and evaporation from land surface (119,000 -

74,200 = 44,800 km3/year) represents the total runoff of Earth’s

rivers (42,600 km3/year), and a direct groundwater runoff to

the ocean (2200 km3/year). Base flow for major rivers such as

the Mississippi, Niger, and Yangtze comes from groundwater

sources.

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Periods of water resources renewal on the Earth

World Ocean 2500 years

Ground water 1400 years

Polar ice 9700 years

Mountain glaciers 1600 years

Ground ice of the permafrost zone 10000 years

Lakes 17 years

Bogs 5 years

Soil moisture 1 years

Channel network 16 days

Atmospheric moisture 8 days

Biological water several hours

Surfacewater and groundwater pollution effectively decreases

the quantity of usable freshwater. Many of the world’s lakes,

large rivers, and estuaries have been contaminated with

anthropogenic effluent discharges. One litre of wastewater

pollutes about eight litres of freshwater. Contamination of

surfacewater has led many regions of the world to turn to

groundwater. An estimated 12,000 km³ of polluted water

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worldwide, which is more than the total amount contained in

the world’s ten largest river basins. Therefore, if pollution keeps

pace with population growth, the world will effectively lose

18,000 km³ of freshwater by 2050 - almost nine times the total

amount countries currently use each year for irrigation.

What is ground water?

It may probably be some kind of magic for the kids when they

pull down a handle of a hand pump and cool freshwater comes

out of the ground below their feet. 97% of liquid freshwater is

stored underground in aquifers within a few kilometers of the

earth’s surface almost everywhere, beneath hills, mountains,

plains, and deserts. Water at very shallow depths might be just

a few hours old; at moderate depth, it may be 100 years old;

and at great depth or after having flowed long distances from

places of entry, water may be several thousands of years old..

Ground water is an important part of the water cycle, and is

the part of rainfall that seeps down through the soil until it

reaches rock material that is saturated with water. The ground

above the water table may be wet to a certain degree, but it

does not stay saturated. The unsaturated zone contains air and

some water and support the vegetation on the Earth. The

saturated zone below the water table has water filled in the

tiny pores between rock particles and the cracks of the rocks.

Why is there ground water?

A couple of important factors are responsible for the existence

of ground water:

(1) Gravity: Ground water slowly moves underground,

generally at a downward angle (because of gravity), and

may eventually seep into streams, lakes, and oceans.

(2) The rocks below our feet: The rock below the Earth’s

surface is the bedrock. But Earth’s bedrock consists of

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many types of rock, such as sandstone, granite, and

limestone. Bedrocks have varying amounts of void spaces

in them where ground water accumulates and can also

become broken and fractured; creating spaces that can

fill with water. Some bedrock, such as limestone, is

dissolved by water — which results in large cavities that

fill with water. Most of the void spaces in the rocks below

the water table are filled with water. But rocks have

different porosity and permeability characteristics, and

water does not move around the same way in all rocks.

Gravity doesn’t pull water all the way to the center of the

Earth. Deep in the bedrock there are rock layers made of dense

material, such as granite, or material that water has a hard time

penetrating, such as clay. These layers may be underneath the

porous rock layers and, thus, act as a confining layer to retard

the vertical movement of water. Since it is more difficult for

the water to go any deeper, it tends to pool in the porous layers

and flow in a more horizontal direction across the aquifer

Basic Information

WATER - A KEY DRIVING FORCE

24

toward an exposed surface-water body, like a river. Often a

large amount of the water flowing in rivers comes from seepage

of ground water into the streambed, depending on region’s

geography, geology, and climate. Ground-water pumping can

alter how water moves between an aquifer and a stream, lake,

or wetland by either intercepting ground-water flow that

discharges into the surface-water body under natural

conditions, or by increasing the rate of water movement from

the surface-water body into an aquifer.

Ground-water aquifers and Water Levels in Wells

When a water-bearing rock readily transmits water to wells

and springs, it is called an aquifer. Sometimes the porous rock

layers naturally remain tilted in the earth. There might be a

confining layer of less porous rock both above and below the

porous layer. This is an example of a confined aquifer. In this

case, the rocks surrounding the aquifer confine the pressure in

the porous rock and its water. If a well is drilled into this

“pressurized” aquifer, the internal pressure might (depending

on the ability of the rock to transport water) be enough to push

the water up the well and up to the surface without the aid of

a pump, sometimes completely out of the well. This type of

well is called artesian.

Wells can be drilled into the aquifers and water can be

pumped out. Precipitation eventually adds water (recharge)

into the porous rock of the aquifer. Seasonal variations in

rainfall and the occasional drought affect the “height” of the

underground water level. The rate of recharge is not the same

for all aquifers, though, and that must be considered when

pumping water from a well. Pumping too much water too fast

as compared to the recharge rate draws down the water level

in the aquifer and eventually causes a well to yield less and

less water and even run dry. In fact, pumping a well too fast

25

can even cause neighbor’s well to run dry if both are pumping

from the same aquifer. When water levels drop below the levels

of the pump intakes, then wells will begin to pump air - they

will “go dry.”

Ground water serves many purposes

The main uses of ground water include irrigation uses, drinking

water and other public uses, and for supplying domestic water

to people who do not receive public-supply water. In many

areas, the majority of water used for self-supplied domestic

and livestock purposes come from ground-water sources. Fresh

ground water is used for many important purposes, with the

largest amount going toward irrigating crops. Local city water

agencies withdraw a lot of ground water for public uses, such

as for delivery to homes, businesses, and industries, as well as

for community uses such as firefighting, water services at

public buildings, and for keeping local residents happy by

keeping community swimming pools full of water. Industries

and mining facilities also used a lot of ground water.

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WATER - A KEY DRIVING FORCE

26

Groundwater exploitation is regulated mainly through control

of borehole drilling or licensing their pumping. Due to absence

of any pricing mechanism and strict regulation, indiscriminate

groundwater exploitation, its wasteful utilization, and land

disposal of wastes continued. In some places, groundwater is

linked to land ownership while in others it is viewed as a

‘common property’. Some of the important parameters of

interest to the planners and managers are recharge ability of

groundwater; quantity and quality; location of recharge intake

areas; inter-linkage between groundwater and surface water;

sources of pollution, etc.

Water quality

Good quality water is an aqueous solution of carbonates,

bicarbonates, sulphates and chlorides of the alkali metals

and alkaline earths, at low concentration level within the

maximum permissible limit prescribed for drinking water.

The process of induction of objectionable matter in

groundwater and thereby changes in its physical, chemical

and other properties, as to render it unfit for various

purposes, is called pollution. Salinization of groundwater,

an important parameter for judging the quality of water, is

caused by both primary as well as a secondary phenomenon,

connected with the lithology of the rock types, temperature,

climatic conditions of the terrain and hydrography of the

surface basins. Surface water or Groundwater chemically

evolves by interacting with naturally occurring minerals in

the rocks and aquifer and sediments, external pollutant

sources from industrial discharges, urban activities,

agriculture, and internal mixing among different

groundwaters along specific flow-paths. The most common

water-quality problem in rural water supplies is bacterial

contamination from septic tanks, which are often used in

rural areas that don’t have a sewage-treatment system.

27

Effluent (overflow and leakage) from a septic tank can

percolate (seep) down to the water table and maybe into a

homeowner’s own well.

The physical properties of a groundwater aquifer, such

as thickness, rock or sediment type, and location, play a large

part in determining whether contaminants from the land

surface will reach the ground water. The risk of

contamination is greater for unconfined (water-table)

aquifers than for confined aquifers because they usually are

nearer to land surface and lack an overlying confining layer

to impede the movement of contaminants. Because ground

water moves slowly in the subsurface and many

contaminants adsorb to the sediments, restoration of a

contaminated aquifer is difficult and may require years,

decades, centuries, or even millennia. Deterioration of water

quality has a severe negative impact on ecosystems and

habitats that support plant and animal life; and decreases

the suitability of water for all purposes and increases the

cost of making it available for use.

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WATER - A KEY DRIVING FORCE

28

Broadly categorized sources that can affect water quality

(a) Point Sources: Those readily identifiable at a single

location, such as industries, municipal sewage

treatment plants, septic tanks, combined sewer

overflows and raw sewage discharges.

(b) Non-Point Sources: Those diffuse discharges whose

location can not be identified. The main sources are

agriculture, forestry, mining, construction, urban run-off,

hydrological modifications and residual wastes. Some of

the common non-point sources of contaminants are

fertilisers, farmyard manure and compost used for

Inorganic contaminants found in ground water

Contaminant Sources to ground Potential health and

water other effects

Antimony Natural minerals, Decreases longevity,

municipal waste, alters blood levels of

manufacturing of glucose and cholesterol

glass, flame- in laboratory animals

retardants, exposed at high levels

explosives ceramics, over their lifetime.

batteries, fireworks,

Arsenic Natural processes, Causes acute and chronic

industrial waste, toxicity, liver and kidney

pesticides, smelting damage; decreases

of copper, lead, and blood hemoglobin.

zinc ore.

Barium Occurs naturally Can cause cardiac,

in some lime gastrointestinal, and

stones, sandstones, neuromuscular effects and

and soils. hypertension in humans

andcardiotoxicity in

animals

Beryllium Soils, rocks, coal, Causes acute and chronic

petroleum. Mining toxicity; damage to lungs

operations, processing and bones. Possible

plants, and waste carcinogen.

disposal.

29

Cadmium Found in rocks, coal, Causes high blood pressure,

and petroleum. liver and kidney damage,

Mining waste, metal and anemia. Destroys

plating, Industrial testicular tissue and red

discharge, plastic blood cells. Toxic to aquatic

stabilizers, water biota.

pipes, batteries,

paints, pigments,

landfill leachate.

Chloride Saltwater intrusion, Deteriorates plumbing,

mineral dissolution, water heaters, and water-

industrial and works equipment at

domestic waste. high levels.

Chromium Old mining operations Chromium VI is much more

runoff, mineral toxic than Chromium III and

leaching, fossil-fuel causes liver and kidney

combustion, mineral damage, respiratory

leaching, metal damage, internal

plating, cooling hemorrhaging, dermatitis,

tower water additive, and ulcers on the skin at high

cement-plant levels.

emissions, waste

incineration.

Copper Metal plating, Can cause stomach and

industrial and intestinal distress, liver and

domestic waste, kidney damage, anemia in

mining, and mineral high doses. Imparts an

leaching. adverse taste and significant

staining to clothes and

fixtures.

Cyanide Electroplating, Poisoning is the result of

plastics, steel damage to spleen, brain,

processing, synthetic and liver.

fabrics, fertilizer

production.

Fluoride Geological minerals; High levels can stain or

additive to municipal mottle teeth. Causes

water supplies; crippling bone disorder at

industry, phosphate very high levels.

rocks.

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WATER - A KEY DRIVING FORCE

30

Iron Natural mineral, Imparts a bitter astringent

rocks, mining, taste to water and a

industrial waste and brownish color to laundered

corroding metal. clothing and plumbing

fixtures.

Lead Industry, mining, Affects red blood cell

plumbing, gasoline, chemistry; delays normal

coal, and water physical and mental

additive. development in babies and

young children. Causes

slight deficits in attention

span, hearing, and learning

in children. Can cause slight

increase in blood pressure in

adults.

Manganese Natural mineral Causes aesthetic and

from sediment and economic damage, imparts

rocks or from mining brownish stains to laundry.

and industrial waste. Affects taste of water, and

causes dark brown or black

stains on plumbing fixtures.

Toxic to plants at high levels.

Mercury Industrial waste, Causes acute and chronic

mining, pesticides, toxicity. Targets the kidneys

coal, electrical and can cause nervous

equipment (batteries, system disorders.

lamps, switches),

smelting, and fossil-

fuel combustion.

Nickel Electroplating, Damages the heart and liver

stainless steel of laboratory animals

and alloy products, exposed to large amounts

mining, and refining. over their lifetime.

Nitrate; Natural mineral Causes “blue baby disease,”

Nitrite deposits, soils, or methemoglobinemia,

seawater, which threatens oxygen-

freshwater systems, carrying capacity of the

atmosphere, biota, blood.

fertilizer, feedlots,

and sewage.

31

Selenium Naturally occurring Causes acute and chronic

geologic sources, toxic effects in animals—

sulfur, and coal. ”blind staggers” in cattle.

Toxic at high doses.

Silver Ore mining and Can cause argyria, a blue-

processing, gray coloration of the skin,

photography, mucous membranes, eyes,

electroplating, and organs in humans and

alloy, solder product animals with chronic

fabrication and exposure.

disposal.

Sulfate Saltwater intrusion, Forms hard scales on boilers

mineral dissolution, and heat exchangers; can

and domestic or change the taste of water,

industrial waste. and laxative effect in high

doses.

Thallium Electronics, Damages kidneys, liver,

pharmaceuticals brain, and intestines in

manufacturing, glass, laboratory animals when

and alloys. given in high doses over

their lifetime.

Zinc Industrial waste, Imparts an undesirable taste

metal plating, to water. Toxic to plants at

plumbing, and high levels.

sludge.

Organic contaminants found in ground water

Contaminant Sources to ground Potential health and

water other effects

Volatile Industries of plastics, Can cause cancer and

organic dyes, rubbers, liver damage, anemia,

compounds polishes, solvents, blurred vision,

crude oil, insecticides, gastrointestinal disorder,

inks, varnishes, skin irritation,

paints, disinfectants, exhaustion, weight loss,

gasoline products, nervous system damage,

pharmaceuticals, and respiratory tract

preservatives, spot irritation.

removers, paint

removers, degreasers,

and many more.

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WATER - A KEY DRIVING FORCE

32

Pesticides Herbicides, Cause poisoning,

insecticides, numbness, weakness,

fungicides, cancer, headaches,

rodenticides, gastrointestinal

and algicides. disturbance, dizziness.

Destroys nervous

system, thyroid,

reproductive system,

liver, and kidneys.

Plasticizers, Waste disposal, Cause cancer. Damages

chlorinated leaching runoff, nervous and

solvents, leaking storage reproductive systems,

benzo [a] tank, and industrial kidney, stomach, and

pyrene, and runoff of sealants, liver.

dioxin linings, solvents,

pesticides, plasticizers,

components of

gasoline, disinfectant,

and wood preservative.

Microbiological contaminants found in ground water

Coliform Occur naturally in Bacteria, viruses, and

bacteria soils and plants; in parasites can cause

the intestines of polio, cholera, typhoid

humans and other fever, dysentery, and

warm-blooded infectious hepatitis.

animals.

Radiological contaminants found in ground water

Gross alpha- Weapons, nuclear Damages tissues and

particle activity; reactors, medical destroys bone marrow.

Beta-particle treatment and

and photon diagnosis, mining

radioactivity radioactive material,

and radioactive

geologic formations.

Combined Historical industrial- Causes cancer in the

radium-226 and waste sites are the bone and skeletal

radium-228 main man-made tissue.

source.

33

agricultural purposes, and land-disposed industrial

effluents from brick kilns, plating, galvanising, rayon

manufacture, rubber processing, pickling, and iron and

steel production. Regular applications of nitrogenous

fertilisers, phosphate fertilisers (which contain ~1-3% F),

fumigants, rodenticides, insecticides and herbicides

containing fluoride as impurity or constituent, and other

such agrochemicals, as well as indiscriminate disposal

of wastes, are likely to create a blanket non-point source

of contaminants.

A wide variety of chemical and physico-chemical

processes, such as, denitrification, precipitation, dissolution,

hydrolysis, transformation/degradation, complex formation,

redox equillibria, colloid formation, diffusion, dispersion,

convection and sorption/desorption, can be expected to alter

the quality of groundwater. In a watershed, gradients in

groundwater quality and contaminant levels can have a variety

of configurations, depending locally on both transient and

steady state variables, such as geological, geomorphological,

hydrological, mineralogical, depth to confinement, weathering

history and other related features. These include: (1) changes

in contaminants concentration in recharging groundwaters

over time, and (2) the distance, direction and time between

recharge and discharge of contaminated groundwaters, and

the distribution and effectiveness of natural remediation.

Water properties

Pure water is virtually colorless and has no taste or smell. But

the qualities of water make it a most interesting. Water’s

chemical description is H2O that is one atom of oxygen bound

to two atoms of hydrogen. The hydrogen atoms are “attached”

to one side of the oxygen atom, resulting in a water molecule

having a positive charge on the side where the hydrogen atoms

are and a negative charge on the other side, where the oxygen

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WATER - A KEY DRIVING FORCE

34

atom is. Due to opposite electrical charges, water molecules

attract each other, and tend to clump together making it kind

of “sticky.” The side with the hydrogen atoms (positive charge)

attracts the oxygen side (negative charge) of a

different water molecule. This is why water

drops are, in fact, drops! Water’s melting and

boiling points are higher than that of similar

compounds. It is unusually viscous based on

its comparatively small molecular weight.

Water has the ability to act as either an acid or a base depending

on the circumstances, and by its nature it is perfectly neutral.

Though polar in its make up, it exhibits

properties that indicate a sort of polymerizing

link between its molecules. While it exists on

earth in all three basic states, solid, liquid, and

gas; water’s properties are often bizarre by

most standards. For example liquid water

contracts when cooled until it reaches a

temperature of about 40Celsius where it

reaches its maximum density. When this

temperature is reached liquid water begins to

expand, and even with a change in state to ice,

water continues to expand, by reducing its

density as its temperature decreases. Water

reacts with more substances than any other

compound. It reacts physically with several compounds to add

to their crystal structure. Compounds like copper and

magnesium sulfate are two examples of many compounds that

almost always found in nature with water molecules physically

attached to their crystal structure. These compounds are natural

dehumidifiers, dependent on water to complete their structure.

Many organic compounds get their oxygen and/or hydrogen

from reactions with water. Water molecules have a unique

ability to be energized by microwave radiation, and at the same

–

++

HH

O

–

++

HH

O

–

++

HH

O

–

++

HH

O

35

time make an excellent barrier to nuclear radiation. It absorbs

neutrons in nuclear power plants, yet is easily heated by

microwaves.

Water as a solvent

Water is called the “universal solvent” because it dissolves

more substances than any other liquid. When water is the

solvent, the solution is said to be an aqueous solution. In water,

the molecules are held close together by hydrogen bonding

that cause water to exist as a liquid at the temperatures and

pressures that normally prevail on the Earth’s surface. Life

depends on this property. Since there is so much water in living

organisms, water is a very important solvent. Substances such

as glucose dissolve in the water of the blood, which allows it

to be carried around the human body. In plants, the most

commonly transported substance is sucrose, which is also

soluble in water. Water plays a very significant role in our

sleeping course. Our body is mostly made up of water, and it

will not function well if there is insufficient supply of it in the

system. In a day, 10 to 12 cups of water is lost from our body!

So, if the water lost is not replaced, blood clusters together and

becomes powerless to carry adequate amount of oxygen to all

parts of the body, making the body feel frail, declining the

ability to ponder or think well, and reducing the energy level

at minimum. Worst of all, it would lower the body’s resistance

against stress, sickness, or diseases as a result of a weak immune

system. If the body is dehydrated, blood flow to our

fundamental organs would dwindle during sleep.

Furthermore, having an adequate amount of water in the body

helps normalize the body temperature rhythm.

Thermal capacity

Water is also extremely useful due to its high heat capacity;

that is, a large amount of heat energy is required to raise the

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WATER - A KEY DRIVING FORCE

36

temperature of water. It has an enormous ability to absorb and

transmit energy, because, much of the energy is used to break

the hydrogen bonds, which restrict the mobility of the

molecules. As a result, water is relatively slow to heat up or

cool down. In fact, the specific heat capacity of liquid water is

the highest of any known substance. The latent heat (enthalpy)

of fusion of water (the heat energy needed to melt ice) is

unusually high. Therefore, relatively large amounts of heat

energy must be extracted from liquid water before it freezes.

For example, the amount of energy to melt 1 kg of ice at 00C

would be enough to lower the temperature of 1 kg of

Aluminum over 5700 C. The latent heat of vaporisation of water

(the heat energy required to vaporise liquid water) is also

unusually high, and thus has a remarkable cooling effect. Most

liquids contract on cooling, reaching their maximum density

at their freezing point. Water is unusual in reaching its

maximum density above its freezing point - at 4°C. So when

water freezes the ice formed is less dense than water and floats

on top. Ice on the surface effectively insulates the water below,

thereby making it less likely that the bulk of water (sea, pond

or lake) will freeze up even if the air above is very cold. This

prevents large bodies of water from freezing solid and

contributes to the survival of aquatic organisms.

Cohesion, Adhesion, surface tension and capillarity

The hydrogen bonding of water results in strong cohesive

forces. Due to this, the surface of a water drop assumes the

smallest possible area, and forms a sphere. At the surface of

water, the molecules are orientated such that most hydrogen

bonds point inwards towards other water molecules. This gives

water a very high surface tension, higher than any other liquid

except mercury. The ability of water to cling readily to other

molecules is responsible for the upward movement of water

37

when a small-bore tube is dipped into it. This phenomenon is

called capillarity. Theoretically, plant xylem vessels (dia.

0.02mm) can support a water column of height 1.5m by

capillarity forces. One of its main biological effects is the

upward movement of water in the soil. Without sufficient water

at appropriate time most new technological inputs such as

HYVs, fertilizers are relatively ineffective. Water shortages

severely affect crops by reducing seed germination, seedling

emergency, photosynthesis, respiration, leaf number and seed

number and seed filling. Water stress limits the limits the

metabolism of nitrogen and other nutrients in crops.

Water Facts

Most of the earth’s surface water is permanently frozen

or salty. Complete melting of polar ice caps would rise

the oceans about 240 ft above its present level.

If all the world’s water were fit into a gallon jug, the fresh

water available for us to use would equal only about one

tablespoon.

Showering, bathing and using the toilet account for about

two-thirds of the average family’s water usage.

The average person needs 2 quarts of water a day.

Approximately 66% of the human body consists of water.

The total amount of water in the body of an average adult

is 37 litres.

Human brains are 75% water; Human bones are 25%

water.

Human blood is 83% water.

A person can live about a month without food, but only

about a week without water. If a human does not absorb

enough water dehydration is the result.

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38

A person must consume 2 litres of water daily to live

healthily. Humans drink an average of 75.000 litres of

water throughout their life.

It takes enourmous amount of water to produce crops:

one to three cubic metres to yield just one kilo of rice, and

1,000 tons of water to produce on ton of grain.

About 6,800 gallons of water is required to grow a day’s

food for a family of four.

1000 tons of water is required to produce one ton of wheat.

2,000 tons of water is required to produce one ton of rice.

95% of a tomato is water. 85% of a potato is water. 80% of

a pineapple is water.

Each day the sun evaporates a trillion tons of water.

A single tree will give off 265 liters of water per day in

evaporation.

An acre of corn will give off 15,000 litres of water per day

in evaporation.

It takes almost 49 gallons of water to produce just one

eight-ounce glass of milk. That includes water consumed

by the cow and to grow the food she eats, plus water used

to process the milk.

A small drip from a faucet can waste as much as 75 litres

of water a day.

Humans daily use about 190 litres of water.

Two thirds of the water used in a home is used in the

bathroom.

To flush a toilet we use 7.5 to 26.5 litres of water.

In a five-minute shower we use 95 to 190 litres of water.

To brush your teeth you use 7.5 litres of water.

Only 30 per cent of the world’s people have a guaranteed

supply of treated water. The remaining 70 per cent depend

39

on wells; bore holes and other uncertain sources of water

supply, all liable to contamination.

In a 100-year period, a water molecule spends 98 years in

the ocean, 20 months as ice, about 2 weeks in lakes and

rivers, and less than a week in the atmosphere.

Amount of time that groundwater, once polluted, can

remain polluted: several thousand years.

Source: http://www.nps.gov/rivers/waterfacts.html; http://

www. lenntech.com/water-trivia-facts.htm (accessed on 9th

October, 2006)

In Africa, agriculture consumes 88% of all water, while

domestic use accounts for 7% and industry for 5%. In

Europe, 54% of water is used in industry, 33% in

agriculture and 13% for domestic use.

Almost 70% of all available freshwater is used for

agriculture. Current global water withdrawals for

irrigation are estimated at about 2,000 to 2,555 cubic

kilometres per year.

Pumping of groundwater by the world’s farmers exceeds

natural replenishment by at least 160 billion cubic metres

a year.

Agriculture is responsible for most of the depletion of

groundwater, along with up to 70 per cent of the pollution.

Both are accelerating.

Many of the world’s most important grainlands are

consuming groundwater at unsustainable rates.

Collectively, annual water depletion in India, China, the

United States, North Africa and the Arabian Peninsula

adds up to 160 billion cubic metres a year.

In developing countries, 70% of industrial wastes are

dumped untreated into waters where they pollute the

usable water supply.

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WATER - A KEY DRIVING FORCE

40

More than one billion people on earth already lack access

to fresh drink water. If current trend persists, by 2025,

the demand for freshwater is expected to rise to 56%,

exceeding the amount that is currently available.

By 2000, available freshwater per person dropped to 7,800

cubic metres from 9,000 cubic metres in 1989, and is

expected to plummet to 5,100 cubic metres per person by

2025, when the global population is projected to reach 8

billion.

The world’s six billion people are already using about

54% of all the accessible freshwater contained in rivers,

lakes and underground aquifers. By 2025 the human’s

share will be 70%, based on the population increase.

If per capita consumption of water resources continues

to rise at its current rate, humankind could be using over

90% of all available freshwater within 25 years.

By 2025, according to projections, more than 2.8 billion

people in 48 countries will be facing water stress or

scarcity.

By 2050, the number of water short countries soars to 54,

affecting 4 billion people, or 40% of the projected global

population. The worst hit areas are in the Middle East,

North Africa and in sub-Saharan Africa.

Over 200 million sub-Saharan Africans already live in

water short countries. This figure will increase to 700

million by 2025, of whom over half will live in countries

facing severe shortages for most of the year.

Source: http://www.ozh2o.com/h2use.html (accessed on 19th

October, 2006)

41

3

International Scenario

Water resources distribution over the territory of the Earth

is uneven. The total water resources renewal in the

world is estimated of the order of 43750 km3/year, distributed

throughout the world according to the climates and

physiographic structures. At the continental level, America has

the largest share of the world’s total freshwater resources with

45%, followed by Asia with 28%, Europe with 15.5%and Africa

with 9%. The largest renewable water resources are concentrated

in six principal countries of the world: Brazil, Russia, Canada,

USA, China, and India. Nine countries are the world giants in

terms of internal water resources, accounting for 60% of the

world’s natural freshwater. In terms of absolute value, the largest

exploitable renewable water resources are characteristic of Asia

and South America (respectively, 13,500 and 12,000 km3 pe r yea r).

The smallest are typical for Europe and Australia with Oceania

(respectively, 2900 and 2400 km3 per year). For individual years,

the values of water resources can vary in the range of ±15-25% of

their average values. The specific water availability, i.e., actual

per capita renewable water resources without water consumption,

decreases as population and water consumption grow.

(Note: 1 km3 = 109 m3 = 1 billion cubic metre (BCM) = 0.10 million ha m.)

WATER - A KEY DRIVING FORCE

42

Due to rapid growth in Earth’s population since 1970

to 1994, the potential water availability of Earth’s population

decreased from 12.9 to 7.6 thousand m3 per year per person.

The greatest reduction of per capita water supply took place

in Africa (by 2.8 times), Asia (by two times), and South

America (by 1.7 times). The water supply of European

population decreased for that period only by 16 %. About

60-70% of this runoff is mainly formed during the flooding

period. In terms of resources per inhabitant in each

continent, America has 24000 m3/year, Europe 9300 m3/year,

Africa 5 000 m3/year and Asia 3 400.1 m3/year. At country

level, there is an extreme variability: from a minimum of 10

m3/inhabitant in Kuwait to more than 100000 m3/inhabitant

in Canada, Iceland, Gabon and Suriname. For 19 countries

or territories, the water resource per inhabitant are less than

500 m3; and the number of countries or territories with less

than 1000 m3/inhabitant is 29. The ten poorest countries in

terms of water resources per inhabitant are Bahrain, Jordan,

Kuwait, Libyan Arab Jamahirya, Maldives, Malta, Qatar, Saudi

Arabia, United Arab Emirates and Yemen.

Global water availability per person

(Source: www.unesco.org/courier/2001_10/uk/doss02.htm)

43

The information on the specific water availability, for all

economic regions and selected countries for the 1950-2025

period, suggest that e.g., the greatest water availability of 170-

180 thousand m3 per capita for 1995 was in the regions of

Canada with Alaska and in Oceania. At the same time, in

densely populated regions of Asia, Central and South Europe,

and Africa the present water availability is within 1.2-5

thousand m3 per year. In the north of Africa and on the Arabian

Peninsula, it is as much as 0.2-0.3 thousand m3 per year. It is

worth mentioning that water availability of less than 2000 m3

per year per capita is considered to be very low, and less than

1000 m3 per year catastrophically low. The thresholds of 1000

and 500 m3/inhabitant correspond respectively to water stress

and water scarcity levels.

Regional Overview

In general, the water resources estimated on the basis of surface

water flows, the countries of the world could be broadly

grouped into ten regions composed of various sub-regions. Of

most importance for water supply is the basic runoff; which is

stable, with little variation during a year and year-to-year. Its

value is approximately 37% of the total volume of global river

runoff, or about 16,000 km3 per year. Many regions are

characterized by an extremely uneven river runoff distribution,

and 60 to 80% of annual runoff takes place during 3-4 months.

For instance, 64% of annual runoff passes during three flooding

months in the north and south of the European part of the

Former Soviet Union (FSU); 57% in the central part of North

America and in southern Asia; 59% in Siberia and the Far East;

68% in Australia, and 80% in western Africa. While, the river

runoff for the low flow period, lasting 3-4 months, amounts to

only 8-9% of annual runoff in the north of the European

territory of the FSU, Canada and Alaska, North China and

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WATER - A KEY DRIVING FORCE

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Mongolia; 6.7% in Central America; 4-5% in Siberia and the

Far East, and Southern Asia, and as much as 0.8% in Western

Africa. In almost all regions of the world, unevenness of river

runoff distribution during a year leads to the necessity of its

regulation by creating reservoirs of different types.

Region 1: Northern America - The region, extending over

about 21 million km2, covers 16 % of the world’s land area,

and can be divided into three subregions: (i) Alaska, Canada

and Greenland; (ii) Mexico; and (iii) The United States of

America (conterminous states). Overall, the region is relatively

well endowed with water resources. In Alaska, the annual

precipitation ranges from 1524 to 3810 mm with estimated

natural runoff at 8,01,540 million m3/year to less than 127 mm

in the arctic region. Canada (area of 9.98 million km2), the

second largest country in the world has about 9% of the world’s

freshwater resources. Freshwater bodies cover 7.6% of its area.

The annual precipitation decreases in a northerly direction from

500 mm in the central area to 125 mm in the arctic islands.

Canada has more than 31,000 freshwater lakes, ranging from 3

km2 to more than 100 km2. The Great Lakes store 22,700 km3 of

freshwater, 99% of which is a remnant from the glacial period

and so non-renewable. The United States of America has total

area of 9.36 million km2, and taken as a whole, the conterminous

states receive an average of about 762 mm of precipitation

annually. This region is the home to 7% of the world’s

population; the water resources per person exceed 16000 m3/

year, much higher than the world average.

Region 2: Central America and Caribbean - The region,

occupying about 0.73 million km2 or 0.6% of the world’s total

land area, can be divided into the following subregions: (i)

Central America, occupying 72% of the region, with

precipitation increasing from north to south and from west to

east; and (ii) Caribbean (total area of 0.19 million km2)

45

Renewable water resources and water availability by continents

Continent Area, Population Water resources, Potential water

million (million) (km3 /year) availability,

km21000m 3 /year

Average Max Min Cv per per

km2capita

Europe 10.46 685 2900 3410 2254 0.08 277 4.23

North America 24.3 453 7890 8917 6895 0.06 324 17.4

Africa 30.1 708 4050 5082 3073 0.10 134 5.72

Asia 43.5 3445 13510 15008 11800 0.06 311 3.92

South America 17.9 315 12030 14350 10320 0.07 672 38.2

Australia and Oceania 8.95 28.7 2404 2880 1891 0.10 269 83.7

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consisting of the islands: Greater Antilles and the Lesser

Antilles. The average annual rainfall in the subregion is 1141

mm. The region is relatively well endowed with water

resources, and receives 1.4% of the world’s precipitation and

generates 1.8% of its water resources. With 1.1% of the world’s

population, the water resource per person in the region is

estimated at about 11,900 m3/year, about double the world

average.

Region 3: Southern America - The region, covering about

17.8 million km2 or 13% of the world’s total land area, can be

subdivided into the following subregions: (i) Guyana; (ii)

Andean; (iii) Brazil; (iv) Southern. The Guyana occupies 0.47

million km2 (2.1% of the region’s total area) and precipitation

is highest in the south, 1500-2400 mm/year. The Andean

subregion covers 4.72 million km2 and precipitation increases

towards the north. Brazil (area 8547 million km2) covers 48%

of the region and the south of this subregion has rainfall of

1250-2000 mm/year and in the southeast, the rainfall ranges

from 900-4400 mm/year; the central-west has an average

annual rainfall of 1250-3000 mm/year. The northeast has an

average annual precipitation, irregularly distributed, of 750 mm

to less than 250 mm. The north (with an average 1500-3000

mm/year of rainfall) covers almost the whole of the Amazon

River basin. The Southern subregion total area is 4.1 million

km2 (23.2% of the region’s total area). Overall, the region is

relatively well endowed with water resources, receiving 26%

of the world’s precipitation and generating 28% of its water

resources. Home to 5.7% of the world’s population, the water

resource per person in the region is about 35,000 m3/year, well

above the world average. Chile presents an annual water

availability of 63064 m3/inhabitant. Climate characteristics of

the Central and Southern America generate strong inter-

seasonal and inter-annual variation in water resources,

aggravated by meteorological phenomena such as El Niño.

47

Region 4: Western and Central Europe - The region,

occupying about 3.7% of the world’s total land area and having

8.4% of its population, can be divided into four subregions: (i)

Northern Europe; (ii) Western Europe; (iii) Central Europe; and

(iv) Mediterranean Europe. Overall, water resources are

abundant, with about 2200 km3 in an average year (5% of the

world’s water resources) and 4270.4 m3/inhabitant/year, but

unevenly distributed among countries. The distribution of

precipitation in the region is very diverse, ranging from less

than 300 mm/year in many Mediterranean plains to more

than 3000 mm/year on the coast of the Norwegian Sea. There

are seven main watersheds of more than 1,00,000 km2. The

major one is the Danube Basin (about 8,00,000 km2), which

covers about 17% of the region. On average, river runoff is

about 450 mm/year, varying from less than 50 mm/year in

areas such as southern Spain to more than 1500 mm/year in

various areas of the Atlantic coast and of the Alps. The Danube

River has the largest flow, 205 km3/year. A wide inter-annual

and seasonal variations in runoff characterize the region’s

rivers.

In 2000, renewable water resources per inhabitant ranged

from less than 40 m3/year in Malta and 992 m3/year in Cyprus

to 1140 m3/year in Denmark, 85,500 m3/year in Norway and

more than 6,00,000 m3/inhabitant in Iceland. Some countries

rely heavily on external water resources and would fall under

the threshold of 1000 m3/inhabitant/year if they had to rely

only on their internal resources: Hungary (less than 600 m3/

inhabitant/year), and the Netherlands (less than 700 m3/

inhabitant/year). The Northern Europe has very abundant

water resources per country and per inhabitant (except

Denmark) and its drainage systems are quite large. The Western

Europe has relatively small rivers. The Mediterranean Europe

has a higher level of water resources per inhabitant than the

Western Europe and Central Europe subregions. However, the

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WATER - A KEY DRIVING FORCE

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water resources are unevenly distributed in numerous small

basins, among and within countries.

Region 5: Eastern Europe - The region (total area about

18 million km2) includes the Russian Federation and the eastern

European and Baltic states, covering 13.5% of the world’s land

area and accounting for 3.6% of its population. The regional

water availability is characterized by an extreme variability:

from a minimum of 227 m3 per inhabitant in the Republic of

Moldova to more than 29,000 m3 per inhabitant in the Russian

Federation. However, the water resources in the Russian

Federation are very unevenly distributed. In the more densely

populated western part, annual renewable surface water

resources are estimated at about 2000 m3/inhabitant compared

with up to 1,90,000 m3/inhabitant in the Siberian and Far

Eastern regions. Adding the external flow, all the countries of

the Eastern Europe region show total actual renewable water

resources in excess of 2000 m3/inhabitant. Three countries

depend on other countries for renewable water resources: the

Source: Wor ld R es o urc e s 20 00 -2 0 01 , People and Ecosystesm: The Fraying Web of Life, World Resources Institute (WRI)

Washington DC. 2000.

49

Republic of Moldova for more than 91%, Ukraine for 62%, and

Latvia for 53%. All other countries in the region have more

than 2000 m3/inhabitant/year and four countries have more

than 10,000 m3/inhabitant/year.

Region 6: Africa - The region, occupying 22.4% of the

world’s land area, and 9% of the world’s water, can be divided

into seven climatic subregions on the basis of geography:

Northern Africa; Sudano-Sahelian; Gulf of Guinea; Central

Africa; Eastern Africa; Indian Ocean Islands; Southern Africa.

Northern Africa has very limited water resources, with less

than 10 mm/year on average and faces very severe water

scarcity, with values per inhabitant varying between 200 and

700 m3/year. In terms of internal water resources, it is the

poorest subregion in Africa (1.2% of the continent’s total

internal water resources) and it is the subregion with the highest

percentage of external water resources (63%) due to the Nile

River, which serves only one country. However, the Sahara

has very important fossil groundwater reserves of major

sedimentary aquifers.

The Gulf of Guinea internal resources represent 25% of

the continent’s total water resources, and groundwater acconts

for 30-50% of the subregion’s total water resources. In the

Central Africa, with abundant water resources, represent 48.4%

of the continent’s internal resources and is a major provider of

water to neighbouring subregions. The Eastern Africa has the

Africa’s largest lake (Lake Victoria), yet, the water resources

are limited (6.5% of the continent’s internal resources) In terms

of water resources, after the Democratic Republic of Congo,

Madagascar is the continent’s second richest country. The other

small islands have abundant groundwater resources, scattered

within their territories. The Southern Africa has various major

trans-boundary river basins, and the water resources constitute

7% of the continent’s total. With only 13% of the world’s

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WATER - A KEY DRIVING FORCE

50

population, the region’s water availability is 4979 m³/

inhabitant/year. Considering the region as a whole, transfers

of water from humid to arid zones represent 50% of the water

resources of the arid zones. Another specificity of the region is

the non-renewable important groundwater reserves located in

the large sedimentary aquifers systems (Continental aquifer,

Nubian sandstones, Sahel and Chad watersheds, Kalahari, etc.),

with reserves estimated to be many thousand million cubic

metres. The Libyan Arab Jamahiriya depends heavily on fossil

groundwater to cover its current water demand.

Region 7: Near East - The region can be divided into

subregions: (i) Arabian Peninsula; (ii) Caucasus; (iii) Middle

East. The Near East region covers an area of 6.34 million km2

and includes 250 million people. The region has the lowest per

capita water resources. Precipitation in the region is very low

and variable, and the water resources are particularly sensitive

to drought. While the Near East region covers 4.7% of the

world’s total land area, the water resources are only about 1.1%

of the world’s water. The countries of the Near East region

have less water resources per person than the world average.

The Arabian Peninsula has very limited water resources, with

less than 10 mm/year of rainfall on average, and is in a situation

of very severe water scarcity, with 200 to 700 m3/inhabitant/

year. Some oil-rich countries convert saline water from the sea

or from poor-quality aquifers (brackish water) into drinking

water. The total use of desalinated water in the Near East region

is estimated to be 3.93 km3/year. In absolute terms, Saudi

Arabia, the United Arab Emirates, and Kuwait are by far the

largest users of desalinated water, accounting for 77% of the

total for the region.

Region 8: Central Asia - The region can be divided into

two subregions: Aral Sea countries; and Other countries.

Although the region covers 3.5% of the world’s total land area

51

and contains 1.3% of its population, its water resources are only

about 0.7% of the world’s WR. The average annual renewable

surface water resources in the Aral Sea Basin are estimated at

116 km3, of which 78 km3 in the Amu Darya Basin and 37 km3

in the Syr Darya Basin. The present day inflow to the Aral Sea

is estimated at 1-2 km3/year from the Syr Darya and 5-10 km3/

year from the Amu Darya.

Region 9: Southern and Eastern Asia - The region

occupies about 20.4 million km2, or 15% of the world’s total

land area. China and India combined together account for about

63% of this area. The region can be divided into five subregions

as follows: (i) Indian Subcontinent; (ii) Eastern Asia; (iii) Far

East; (iv) Southeast Asia; and (v) Islands. In the Indian

Subcontinent (area of 3.96 million km2, or about 18% of the

region’s total area), consisting of a large portion of floodplains

along the Indus and Ganges river basins, about 80% of the total

precipitation occurs during the two monsoon periods: the

southwest monsoon (June-September), which brings most of

the rainfall; and the northeast monsoon (November-March).

The average annual precipitation in the subregion is about 1279

mm, varying from less than 150 mm in the northwest desert of

Rajasthan, India, to more than 10 m in the Khasi Hills in

northeast India.

In the Eastern Asia (area 11.3 million km2 or about 55% of

the region’s total area and 8.4% of the world’s total land area),

the average annual precipitation is 597 mm, varying from less

than 25 mm in the Tarim and Qaidam basins in China to 1520

mm in DPR Korea. In the Far East subregion (area is 0.48 million

km2 or 2% of the total area of the region), the average annual

precipitation is 1634 mm, most falling during the summer

months from June to September. In the Southeast Asia (area

1.94 million km2, or 9.5% of the total area of the region), the

average annual rainfall is 1877 mm, ranging from 500 mm in

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WATER - A KEY DRIVING FORCE

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the central dry zone in Myanmar and 650 mm in Phan Rang in

Viet Nam to more than 4000 mm in the mountains of Rakhine

in Myanmar and Bac Quang in Viet Nam. In the Islands

subregion (3.0 million km2, or about 15% of the area of the

region), the average annual rainfall is 2823 mm, ranging from

less than 1000 mm in Port Moresby to more than 8000 mm in

some mountainous areas in Papua New Guinea.

The region has quite humid climates (with annual

precipitation above 10 m) in some placesand in other parts, a

very arid climate. As a result, the region shows a very uneven

distribution and use of its water resources. In India, the flow

distribution of selected rivers in the monsoon period represents

75-95% of the total annual flow. In north China, 70-80% of the

annual runoff is concentrated in the rainy season. Overall, the

region is relatively well endowed with water resources. While

occupying 15.8% of the world’s land surface, it receives 22%

of its precipitation and produces 27% of its water resources.

However, in terms of water resources per inhabitant, the Indian

Subcontinent, Eastern Asia and Far East subregions show the

lowest figures while the figures for the Southeast Asia and

Islands subregions are considerably higher than the world

average.

Region 10: Oceania and Pacific - The region covering an

area of 8 million km2 or 6 % of the world’s total land area, can

be subdivided into two subregions: Australia: Australia; and

Other countries. The countries of this region are mostly islands

of very different types. Some of the islands have a tropical

climate governed mainly by the change between the wet season,

with heavy rainfall, and the dry season. About 75% of the total

rainfall occurs during the wet season. This results in a large

difference in the water level in rivers between the wet and the

dry seasons. The large islands such as Australia and New

Zealand have very dry to humid climates. Australia is dry, with

53

an uneven geographical and seasonal distribution of rainfall.

River flows are highly variable. Australia has one of the world’s

largest aquifer systems, the Great Artesian Basin estimated at

1.7 million km2 and a storage volume of 8.7 km3.

Global Groundwater Situation

Throughout the world, groundwater balance is shrinking day

by day. Groundwater is also critical in supplying the industrial

water demand in most countries. In some of the most populous

and poverty-stricken regions of the world—particularly in

South Asia—groundwater has emerged at the center-stage of

the food-agricultural economy. In regions with high population

density, dynamic tube-well-irrigated agriculture, insufficient

surface water, and inadequate drainage, many consequences

of groundwater problems are becoming increasingly evident.

The most daunting challenges that the world faces in the water

sector are decline in water tables due to overdraft; waterlogging

and salinization; and pollution due to agricultural, industrial

and other human activities. The estimates of 1997 suggest that

the groundwater use for the world as a whole is around 750–

800 km3 annually, which appears modest compared to overall

water availability. But an overwhelming majority of the world’s

cities and towns depend on groundwater for municipal water

supplies.

Half of the US population draws its domestic water

supply from groundwater. During 1990s, India, China, the US

and Pakistan together used about 325 km3 of gro undwater ev ery

year; and over 35 countries of the world used more than 1 km3

of groundwater annually. In comparison, world’s aggregate

groundwater resources appear abundant. Groundwater, both

stock and flow, constitutes over two-third of the world’s

freshwater resource, if we exclude glaciers and permanent

snow cover. Even if 8% of the 33,000 km3 floodwater that runs

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WATER - A KEY DRIVING FORCE

54

off to the oceans annually recharge the groundwater, we have

a renewable supply of over 2,500 km3 of gr oun dwa ter annually,

which seems several times more than the world uses.

According to FAO’s AQUASTAT, the Russian Federation uses

less than 5% of its 900 km3 of annual recharge; West Africa

uses less than 1%; China’s renewable groundwater supply is

estimated at over 800 km3; but it uses just around 70%; even

India, which has serious overexploitation problems uses only

33% of the estimated annual recharge of some 450 km3.

Urban industrialization is also a major contributor to

urban groundwater problems. In the Fuyang river basin of

North China the water table has fallen from 8 to 50 meters

during 1967–2000 and industries are polluting the upper zones;

in South Korea’s industrial cities such as Seoul, Pusan and

Daegu, water tables have dropped by 10–50 meters over a 30-

year period due to industrial pumping. In the Cheju island,

seawater intrusion in coastal aquifer has been the direct result

of industrial pumping of groundwater. Mexico’s aquifers too

55

are amongst the most overdeveloped; Guanajuato State, one

of Mexico’s agriculturally dynamic regions, water tables in 10

aquifers are declining at average annual rates of 1.79–3.3

meters/year during recent years. Groundwater problems in

West and South Asia are as pernicious as or even worse than

those in China. Bangkok, Jakarta and Mexico city have been

facing acute problems of land subsidence because of

groundwater depletion. Aquifer pollution—from both point

and nonpoint sources—is becoming extensive worldwide. In

the Gediz basin of Anatolia, Turkey, nonpoint pollutants—

mostly agrochemicals—have polluted the groundwater and the

river downstream. One of the most serious ill effects of

depletion is from seawater intrusion in coastal aquifers as in

Egypt, Turkey, China and India.

Access to an improved drinking water source: Increased

from 77% of the population in 1990 to 83% in 2002. Despite

this progress, still over one billion people have yet to benefit,

International Scenario

Source: www.growthconsulting.frost.com/web/images.nsf...

(Accessed on 16.10.2006)

WATER - A KEY DRIVING FORCE

56

with coverage in rural areas lagging seriously behind that in

urban areas, with 95% of the urban population having access

to improved water sources in 2002 compared to 72% of the

rural population. Inadequate water supply and sanitation

affects multiple dimensions of poverty, including health,

education and degradation of the environment. In 2002, about

3,900 children under five died each day because of diarrhea

attributed to unsafe water supplies and poor sanitation and

hygiene. Access to an improved water source would be an

important step toward improving health outcomes.

57

4

Indian Scenario

India, with a total area of 3,287,263 Km2, is endowed with

abundant water in the perennial resources of Himalayan

glaciers, the water generated by monsoons, the groundwater

resources and a long coastline. Yet, the actual distribution over

space and time is strongly influenced by a number of climatic

and geographic factors, and freshwater crisis exists in many

parts at different times of a year. Two-third of available

freshwater is lost due to evaporation and runoff into the Sea.

Over the years, the annual per capita availability of renewable

freshwater has shrunk alarmingly, to meet the demands of

different sectors. From around 5,277 cubic metres in 1955 it

dipped to below 1,820 cubic metres in 2001. India is the second

largest water consuming country in the world, after China, and

per capita water consumption is less than the world average

by 7.6%. The domestic sector demand accounts for only 5% of

the annual freshwater withdrawals, and over the next twenty

years is likely to increase from 25 billion m3 to 52 billion m3.

With increasing population and depleting water resources, the

per capita water consumption in India is expected to decrease

at a compound annual growth rate of approximately 1%, during

the period 2003-2006. With increase in industrial production,

WATER - A KEY DRIVING FORCE

58

water consumption for this sector has grown and will continue

to grow at a rate of 4.2% per year. According to the World Bank,

demand of water for industrial, energy production and other

uses will rise from 67 billion m3 to 228 billion m3 by 2025.

Agriculture remains central to the Indian economy and

is heavily dependent on irrigation. Due to a large annual

regional and seasonal variation in rainfall, agriculture receives

a greater share of the annual water allocation. Water demand

for agriculture in 1990 was 46 mhm, and is likely to go up to 77

mhm by 2025. Irrigation accounts for over 95% of freshwater

withdrawals consumed in several States and roughly 80%

nationwide. India has the largest irrigation infrastructure in

the world, but the irrigation efficiencies are low, at around 35%.

By the yardstick of irrigation efficiency and not by the net area

irrigated, doubtless, groundwater is the most important

resource. Groundwater alone accounts for 39% of the water

used in agriculture and surface water use often comes at the

expense of other sectors such as the industrial and domestic

supply. Over 80% of the rural domestic water comes from

groundwater sources. This dependence on groundwater is

particularly critical where dry season surface water levels are

low.

200 million people do not have access to clean drinking

water. Currently, only 85% of the urban and 79% of the rural

population has access to safe drinking water and fewer still

have access to adequate sanitation facilities. Although, most

urban areas in India are serviced by a municipal water supply

system, usually originating from local reservoirs or canals, or

imported through inter-basin transfer, these schemes often do

not adequately cover the entire urban population and are

inefficient and unreliable with zonal disparity. Since colonial

times and after independence, these systems did not receive

as much attention as desirable, in favor of large dam and canal

59

irrigation projects, which could provide water to selected parts

of India. Yet, high economic, social and environmental costs

have not provided their overall benefit. Still, in rural areas

where water is scarce, women have to travel long distances to

wells or streams to fetch water.

Physiography: India can be divided into well-defined

regions: (i) The Northern Mountains, comprising the mighty

Himalayan ranges; (ii) the Great Plains, traversed by the Indus

and Ganga-Brahmaputra river systems; (iii) the Central

Highlands, consisting of the Aravalli ranges in the west and

terminating in a steep escarpment in the east. The area lies

between the Great Plains and the Deccan Plateau; (iv) the

Peninsular Plateaus comprising the Western Ghats, Eastern

Ghats, North Deccan Plateau, South Deccan Plateau and

Eastern Plateau; (v) the East Coast, a belt of land of about 100-

130 km wide, bordering the Bay of Bengal land lying to the

east of the Eastern Ghats; (vi) the West Coast, a narrow belt of

land of about 10-25 km wide, bordering the Arabian Sea and

lying to the west of the Western Ghats, and (vii) the islands,

comprising the coral islands of Lakshadeep in Arabian Sea and

Andaman and Nicobar Islands of the Bay of Bengal.

Climate: The great mountain mass, formed by the

Himalayas and its spurs on the North and the ocean on the

South are the two major influences governing the climate. The

first acts as an impenetrable barrier to the influence of cold

winds from central Asia and gives the sub-continent a tropical

type of climate. The second is the source of cool moisture-laden

winds giving it the oceanic type of climate. The Indian climate

ranges from continental to oceanic, from extremes of heat to

extremes of cold, from extreme aridity and negligible rainfall

to excessive humidity and torrential rainfall. The climatic

condition influences to a great extent the water resources

utilization of the country.

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WATER - A KEY DRIVING FORCE

60

Rainfall: The main sour ce o f wa ter in the country - an nua l

rainfall including snowfall, is adequate and estimated to be of

the order of 4000 cu.km (400 mhm), 75% occurs just in the four

months June to September of the monsoon period and 50%

falling in just 15 days. With an average annual rainfall of 1,170

mm, India is one of the wettest countries in the world.

However, there are large variations in the seasonal and

geographical distribution of rainfall over the country. At one

extreme are areas like Cherrapunji, in the northeast, which

receives each year with 11,000 mm rainfall, and at the other

extreme are places like Jaisalmer, in the west, which receives

barely 100-200 mm of annual rainfall. Though the rainfall over

India is slightly above global average, its erratic and uneven

distribution leads to occasional floods and droughts, in

different parts. Only 28% of annual rainfall is available for

utilization; 70 m ha m surface water and 42 mhm groundwater.

The amount of water that can be actually put to beneficial use

is much less due to the constraints in the technology for storing

water and inter-state issues. The storage capacity of all the

surface water storage reservoirs/tanks, existing, under

construction and contemplated, add up to 40 mhm, which is

only about 60% of the utilizable surface water potential and

meager 3% of the average annual rainfall.

Surface Water Resources: India is endowed with many

rivers. There are 15 major basin (drainage area >20,000 km2),

Water Resources Availability

(In Billion Cubic Metre)

Total Precipitation : 4000

Total Water Availability : 1869

Total Utilisable Water : 1122 (690 SW + 432 GW)

India’s Water Resources : 4% of Global Water Resources

61

45 medium (2,000 to 20,000 km2) and over 120 minor (<2,000

km2) rivers, besides numerous ephemeral streams in the

western arid region. Over 90% of river flows occur in just four

months. For large-scale analysis of water-resources, the country

is often separated into 19 major river basins that constitute

about 83-84% of the total drainage area. This, along with the

medium river basins, accounts for 91% of the total drainage.

12 are classified as major rivers, whose total catchment area is

252.8 million hectare (m.ha). Of the major rivers, the Ganga-

Brahmaputra-Meghana system is the biggest with a catchment

Rainfall Distribution in India

(Source: India Meteorological Department; www.imd.ernet.in/

.../jun-sep-rainfall.htm)

Indian Scenario

WATER - A KEY DRIVING FORCE

62

area of about 110 m.ha, which is more than 43% of the

catchment area of all the major rivers. The other major rivers

with catchment area of more than 10 m.ha are the Indus (32.1

m.ha.), the Godavari (31.3 m.ha.), Krishna, (25.9 m.ha.) and

the Mahanadi (14.2 m.ha). The catchment area of medium rivers

is about 25 m.ha and the Subernarekha with 1.9 m.ha.

catchment area is the largest among the medium rivers in the

country. The average flood discharge of Ganga is 50,000 cubic

meter per second and that for the Brahmaputra is 60,000 cubic

meter per second.

The resource potential of the country, which occurs as a

natural run-off in the rivers, is about 1869 km3/year, (as per

the basin-wise latest estimates of the Central Water

Commission) including regenerating flow from groundwater

and the flow from neighbouring countries, considering both

Green water represents the fraction

of rainfall that generates soil

moisture and which supports

terrestrial ecosystems. It is not

returned to groundwater and rivers,

but will eventually evaporate or

transpire through plants

4% Water bodies

1% Wetlands

5% Arid, shrub and barren lands

26% Forests

20% Savannas and grasslands

9% Croplands

Blue water represents the fraction of the precipitation that runs into rivers and aquifers,

and that has a potential for withdrawal. Out of this, the environmental water flow is the

amount of water needed to sustain ecosystem services. The rest of the blue water

flow is available for possible societal use.

Precipitation

Evapotranspiration

Downstream

11%

Irrigation

5%

Return flow

Evapotranspiration

Rainwater partitioning:

India

Source: Stockholm Environemnt Institute. Sustainable Pathways to Attain the Millenium

Development Goals Assessing the Key Role of Water, Energy and Sanitation. 2005.

63

surface and ground water as one system. Of which only 690 km3

are considered as utilizable in view of the constraints of the

present technology for water storage and inter-state issues. A

significant part (647.2 km3/year) of these estimated water

resources come from neighbouring countries: 210.2 km3/year

from Nepal, 347 km3/year from China (Chinese data) and

90 km3/year from Bhutan. An important part of the surface

water resources leaves the country before it reaches the sea:

20 km3/year to Myanmar, 181.37 km3/year to Pakistan

(Pakistani information) and 1 105.6 km3/year to Bangladesh.

The Central Water Commission estimates the groundwater

resources at 418.5 km3/year. Part of this amount, estimated at

380 km3/year, constitutes the base flow of the rivers. The total

renewable water resources of India are therefore estimated at

1 907.8 km3/year.

Major River Drainage Basins in India

(Source: Gupta and Deshpande, 2004).

Indian Scenario

1 Indus

2a Ganga

2(b+c) Brahmaputra + Meghna

3 Godavari

4 Krishna

5 Cauvery

6 Pennar

7 East flowing: between

Mahanadi and Pennar

8 East flowing: between

Pennar and Kanyakumari

9 Mahanadi

10 Brahmani-Baitarni

11 Subernarekha

12 Sabarmati

13 Mahi

14 West flowing: Kachchh,

Saurashtra and Luni

15 Narmada

16 Tapi

17 West flowing: Tapi to

Tadri

18 West flowing: Tadri to

Kanyakumari

19 Inland drainage in

Rajasthan

20 Minor rivers draining into

Bangladesh and Myanmar

WATER - A KEY DRIVING FORCE

64

The availability of water resources in various river basins

of the country is highly uneven. The utilizable water resource

has been assessed as 1,132 BCM. The Ganga-Brahmaputra-

Meghna system, covering only 33% of the area is the major

contributor to water resource, accounting for about 60% in the

total potential of the various rivers and about 40% of utilisable

surface water resources. In a majority of river basins, the present

utilisation is significantly high and is in the range of 50-95% of

utilisable surface resources. But in rivers such as the Narmada

and Mahanadi, the percentage utilisation is quite low, 23% and

34% respectively. While 32% of the total water resources are

still available in the Brahmaputra basin, and 28% of the total

water resources in the Ganga basin, this availability is merely

0.2% in the Sabarmati basin. Catchments of the western coast

rivers occupy only 3% of the land area, and account for 11% of

the water resources. Thus 71% of water resources are available

to only 36% of the area and the rest 64% of area has to do with

remaining 29% of the water resources.

The inland water resources of the country are classified

as rivers and canals; reservoirs; tanks and ponds; beels, oxbow

lakes, derelict water; and brackish water. The total area of

inland water resources is unevenly distributed over the country

with Orissa, Andhra Pradesh, Gujarat, Karnataka and West

Bengal accounting for more than 50% of the inland water

bodies. Other than rivers and canals, the total water bodies

cover about 7 m.ha. Of the rivers and canals, Uttar Pradesh

occupies the first place with a total length of rivers and canals

as 31.2 thousand km, which is about 17% of the total length of

rivers and canals. The other States following Uttar Pradesh are

Jammu & Kashmir and Madhya Pradesh. Among the

remaining forms of the inland water resources, tanks and ponds

have a maximum area (2.9 m.ha.) followed by reservoirs (2.1

m.ha.). The States of Andhra Pradesh, Karnataka and Tamil

Nadu, West Bengal, Rajasthan and Uttar Pradesh, account for

65

62% of the total area under tanks and ponds in the country. As

far as the reservoirs are concerned, major States like Andhra

Pradesh, Gujarat, Karnataka, Madhya Pradesh, Maharashtra,

Orissa, Rajasthan and Uttar Pradesh account for a large portion

of the area. More than 77% of area under beels, oxbow lakes

and derelict water lies in the States of Orissa, Uttar Pradesh

and Assam. Orissa ranks first as regards the total area of

brackish water and is followed by Gujarat, Kerala and West

Bengal.

The distribution of water resource potential in the country

shows that as against the national per capita annual availability

of water at 2208 cu.m., the average availability in the

Brahmaputra and the Barak rivers is as high as 16589 cu.m.

while it is as low as 360 cu.m. in the Sabarmati basin. The

Brahmaputra and the Barak basin with 7.3% of geographical

area and 4.2% of population of the country have 31% of the

annual water resources. Per capita annual availability for the

rest of the country excluding the Brahmaputra and Barak basin

works out to about 1583 cu.m. Any situation of availability of

less than 1000 cu.m. per capita is considered by international

agencies as a scarcity condition. Out of 12 major and 48 medium

river basins in India, the government predicts that by 2025 the

deficit river basins will be Ganga, Subernarekha, Krishna, Mahi,

Tapi, Cauvery, Pennar and Sabarmati. The surplus basins

would be Brhamaputra, Barak, Narmada, Brahmani-Baitarani,

Mahanadi, Godavari and Indus.

Renewable water resources of India are about 4% of the

global availability. In India, annual average per capita fresh

water availability dropped from 5,177 cu.m. in 1951 to 1,820

cu.m. in 2001. It is predicted that by 2025, per capita annual

average fresh water availability will be 1,340 cubic metre

approximately. Already, the potential of most river basins is

being exploited beyond 50% and several basins are considered

Indian Scenario

WATER - A KEY DRIVING FORCE

66

to be water scarce. About 200 million Indians do not have access

to safe and clean water. An estimated 90% of the country’s

water resources are polluted with untreated industrial and

domestic waste, pesticides, and fertilizers. According to the

United Nations Environment Programme, India will be ‘water-

stressed’ before 2005 (a country is considered ‘water-stressed’

if its water availability is between 1000 to 1700 cubic metres

per person). While rural water demand is assessed on an

allocation of 40 litres per capita per day (lpcd), the

corresponding urban demand is against a norm of 135 lpcd.

Population and water availability trends in India

Note : Government projections; increasing secotral demands

planned to be met through new construction

Source: Population Action International 1995; World Bank, 1977a

If the accepted level of allocation (135 lpcd) is to be

sustained in the year 2050, each of the metros will have to search

for fresh sources of water to meet the growing demand. Water

tariffs have remained lowest in the country’s urban centres. In

67

Delhi, Mumbai and Chennai, water is supplied at Rs 0.5, 1.6

and 2.7 per cubic metre respectively. This means that the rich

pay a fraction (less than 10%) of the actual cost of producing

potable water. Such low tariffs can only encourage wasteful

water utilisation.

Trends in ground-water use, 1950-2000

Ground water is a valuable resource in India, and is vitally

important in supplying water for everyday water needs. India’s

groundwater resources are almost ten times its annual rainfall.

According to the Central Ground Water Board of the

Government of India, the country has an annual exploitable

groundwater potential of 26.5 million hectare-meters. Over 80%

of the domestic water supply in India is dependent on

groundwater. However, groundwater is fast depleting. Water

tables have fallen significantly in most areas at the rate of one

to three meters every year and there is a significant pollution

of groundwater from natural as well as manmade sources.

Nearly 85% of currently exploited groundwater is used only

for irrigation. Groundwater accounts for as much as 70-80% of

the value of farm produce attributable to irrigation. Besides,

groundwater is now the source of four-fifths of the domestic

water supply in rural areas, and around half that of urban and

industrial areas. Furthermore, the estimates suggest that India

is using its underground water resources at least twice as fast

they are being replenished. Already, excessive ground water

mining has caused land subsidence in several regions of Central

Uttar Pradesh.

Ground water is used to irrigate crops and supply homes,

businesses, and industries with water, where surface water

sources are scarce or inaccessible. The majority of ground water

goes towards crop irrigation, with the next largest use being

Indian Scenario

WATER - A KEY DRIVING FORCE

68

Water quality in major river systems of India

Class A: Water fit for drinking after proper disinfection.

Class B: Water is fit for bathing.

Class C: Water fit for drinking only after proper treatment

Class D: Water fit for fish and wildlife.

Class E: Suitable only for industrial cooling, irrigation, etc.

Source: www. edugreen.teri.res.in/explore/maps/water.htm

(accessed on 24th Oct, 2006)

69

water withdrawn for public-supply purposes, and it provides

over 50 billion gallons per day for agricultural needs. It is the

source of drinking water for about half the total population and

nearly all of the rural population. Groundwater development is

about 106% in Delhi, 94% in Punjab, 84% in Haryana, 60% in Uttar

Pradesh, 41-51% in the western states, 17-30% in the central states,

and 24-60% in the southern states (CGWB, 1998). Against a critical

level of 85%, there are blocks in Gujarat, Punjab, Haryana and

Rajasthan, where over-abstraction is 100-260%. Many areas of

India are experiencing ground-water depletion, a term often

defined as long-term water-level declines caused by excessive

ground-water pumping, which is a key issue associated with

ground-water use.

Extensive urbanization and land use changes in many

parts of India have caused compaction of the top sub-soil and

significant shrinking of the exposed land surface to direct

infiltration of rainfall (Datta, 2000). Groundwater recharge from

rainfall varies widely from region to region and within the parts

of a region, depending on the frequency, intensity and

distribution of rainfall, evaporation, soil clay content and

landuse. In Delhi area, contemporary recharge is very limited

and ranges from <5-30%, with most parts receiving <5%

recharge (Datta et al, 2001). The average recharge from rainfall

has been reported to be 18% in Punjab, 15% in Haryana, 20%

in western Uttar Pradesh, 1-14% in Rajasthan, 8-14% in Gujarat,

11% in the alluvial deposits of Maharashtra, and 8% in Andhra

Pradesh, (Datta, 2000). A comparison of the results for the

Sabarmati basin with those of the Ganga, the Ramganga and

the Yamuna basins in the Indo-Gangetic Plains indicated a

relatively higher efficiency of winter rains in inducing

groundwater recharge [Datta et al, 1979]. Higher potential

evaporation during monsoon months in Sabarmati basin may

be expected to reduce the net groundwater recharge for a certain

amount of water input [Datta et al, 1980a]. The radiocarbon

Indian Scenario

WATER - A KEY DRIVING FORCE

70

concentrations of confined groundwaters in Gujarat and

Rajasthan indicated significant amounts of fresh water recharge

even in areas far away from the principal recharge areas of

aquifers [Borole et al, 1979].

The volume and level of ground water is decreasing in

many areas of the country due to excessive pumping at a faster

rate than it can be recharged. Over the last three decades, the

rapid expansion in the use of groundwater primarily for

irrigation has contributed significantly to agricultural and

economic development in India. Groundwater irrigation

potential, the number of wells and the number of energized

pump sets have grown exponentially since the early 1950s. With

more than 17 million wells nationwide, groundwater now

supplies more than 50 percent of the irrigated area and, due to

higher yields in groundwater irrigated areas; it is essential for

an even higher proportion of the total irrigated output. The

practice of sale of water, either on cash or on crop sharing basis

has also encouraged rich farmers constructing deep tubewells

Unbalanced groundwater recharge and lowering of the water table: Some

examples

Groundwater over-development in India by region

71

and over-pumping the groundwater. According to some

estimates, 70-80 percent of the value of irrigated production in

India may depend on groundwater irrigation. Current

projections suggest that the rapid rate of development will

continue until the full irrigation potential estimated to be

available from groundwater is reached in about 2007.

In highly urbanized areas, such as Delhi area, annual

recharge being very small, as compared to the groundwater

withdrawal, water table declined by 2-8 m in different parts

during the last decade and 2-20 m during 1960-2000 (Datta et

al, 2001; Rohilla et al, 1999). In the past two decades, water

table in 77% area of the Punjab State, with exploitation as high

as 98%, has fallen by 25-30 cm a year and is now stationed at

50-60 m. Increase in cropping intensity and replacement of less

water consuming crops with more water requiring crops

yielding better economic return has resulted in more water

demand (Datta, 2000; CGWB, 1998). During the last decade,

groundwater table declined by 0.2-3.0 m in Uttar Pradesh, 3-8

m in Haryana, and 7-10 m in Rajasthan. In different blocks of

the north-western Uttar Pradesh, during 1977-1996, water table

declined from 1m to 10 m. In Gujarat, decline in the

groundwater table increased from 1m y-1 in 1970 to 2-8 m y-1 in

1997 (CGWB, 1998). The water table in the Thar Desert, Gujarat

and parts of peninsular India has sunk by 20-60 metres in the

past 35 years. In Jalgaon district of Maharashtra State, during

1981-1996, water table declined by 13.30 m. Considerable

decline (>4 m) in groundwater table, during 1988-1998, has

been observed in other States also. If ground-water levels

decline too far, then the well owner might have to deepen the

well, drill a new well, or, at least, attempt to lower the pump.

Also, as water levels decline, the water yield may decrease,

more energy is required to lift upto the land surface. Using the

well can become prohibitively expensive.

Indian Scenario

WATER - A KEY DRIVING FORCE

72

Deterioration of water quality: some case studies

The country is facing a water quality crisis. Water pollution is

a serious problem surface water resource and biological, toxic

organic and inorganic pollutants already contaminate a

growing number of groundwater reserves. With so many

avenues for its contamination, being a universal solvent, water

tends to dissolve anything and everything that comes its way,

thus changing its quality every minute. One water-quality

threat to fresh ground-water supplies is contamination from

saltwater intrusion. Under natural conditions the boundary

between the freshwater and saltwater tends to be relatively

stable, but pumping can cause saltwater to migrate inland and

upward, resulting in saltwater contamination of the water

supply. Due to public ignorance to environmental

considerations and lack of provisional basic social services,

indiscriminate disposal of increasing anthropogenic wastes on

land, into river and unlined drains, and unplanned application

of agro-chemicals and improperly treated sewage water

continued, resulting in excessive accumulation of pollutants

on the land surface. Sub-surface leaching of contaminants from

landfills as well as seepage from canals/river and drains caused

severe degradation of the groundwater, at many places,

exceeding the WHO prescribed maximum permissible limits

in drinking water.

The groundwater in different parts of Delhi has become

considerably vulnerable to pollution with a wide range of

contaminants. Large part of Delhi area is severely affected by

fluoride (<1-16.0 mg l-1) and nitrate (<20-1600 mg l-1) pollution

of groundwater (Datta et al, 1996a, 1997)). Fluoride and nitrate

levels increased by 2-6 times, during the last decade. In Punjab,

Haryana, Gujarat, Maharashtra and Karnataka, groundwater

nitrate level ranges from <25 mg l-1 to 1800 mg l-1, and fluoride

level 1.5-45.8 mg l-1. High concentration of fluoride (1.5-45.8

73

mg l-1) has been reported from different parts in the other states

also. Highly skewed distribution and wide range of fluoride

and nitrate suggest contamination from both point and non-

point sources. In the absence of known major geological source

of fluoride and nitrate in the NCR, excessive application of

fertilizers and discharges from steel, aluminum, brick and tile

industries, barn yard and silo wastes, and disposal of crop

residues are major causes of pollution.

In West Bengal, the consequences of arsenic

contamination are evident. Trace to excessive amounts of heavy

metals, such as, Zn (3-41 μg/l), Cu (5-182 μg/l), Fe (279-1067

μg/l), Mn (<1-76 μg/l), Pb (31-622 μg/l), Ni (<1-105μg/l), Cd

(<1-202 μg/l) is found mostly in the groundwaters at some

places of Delhi near industrial sites (Datta et al, 1999), Haryana,

Uttar Pradesh, Andhra Pradesh and Madhya Pradesh. Slow

infiltration of agricultural and urban surface run-off, carrying

alongwith pollutants present in agro-chemicals and wastes

generated by human activities, causes contamination (Datta et

al, 1996a, 1997)). Adsorption/dispersion processes in the soil

zone, degrees of evaporation/recharge and lateral inter-mixing

of groundwater determine the level of contaminants in

groundwater. Over-exploitation induced changes in hydraulic

head cause intermixing of contaminated groundwater with

fresh water along specific flow-pathways (Datta et al, 1996),

increasing lateral extension of contaminated groundwater and

decrease in the available fresh water potential. Obviously, limit

of vulnerability to depletion has reached.

Water Demand and Consumption Patterns

Indians consume 470 cubic meters of water per person per year;

Chinese consume 407 cubic meters water per person per year.

In China, one dollar of GNP is produced per every 370 liters of

water; in India 880 liters of water are required. In the USA,

water consumption at 1,606 cubic meters per person per year,

Indian Scenario

WATER - A KEY DRIVING FORCE

74

Ministry/Institution Portfolio

• Ministry of Water Resources Principal agency responsible

for all water in the country

• Ministry of Rural Development Watershed development and

water supply in rural areas

• Ministry of Urban Development Drinking water supply in

urban areas

• Ministry of Power Development of Mega

hydroelectric projects

• Ministry of Non-Conventional Development of micro and

Energy Sources mini hydel potential.

• Ministry of Environment Quality of surface and

and Forests groundwater

• Ministry of Agriculture Providing resources for

irrigation of agricultural

lands

• Ministry of Industry Planning and development of

water for industry

• Central Pollution Control Board Monitoring and regulation of

industrial water pollution

• Central Ground Water Regulation of quantity and

Authority quality of groundwater

• Water Quality Assessment Apex body set up by

Authority MoWR and MoEF, yet to start

effective functioning

Present and Future Water Demand

Sector Water Demand in BCM

Year 2050 2025 2010 2000

Irrigation 1072 910 6885 41

Domestic 102 73 56 42

Industry 63 23 12 8

Energy 130 15 5 2

Others 80 72 52 41

Total 1447 1093 813 634

(Source: Standing Sub-committee on assessment of

availability and requirement of water)

75

a dollar of GNP requires only four liters of water. In the more

water-frugal European Community, where each person

consumes 605 cubic meters of water per year, a dollar of GNP

requires a mere three liters of water. A region where renewable

fresh water availability is below 1700 cubic meters/capita/

annum is a ‘water stress’ region, and one where availability

falls below 1000 cubic meters/capita/annum experiences

chronic ‘water scarcity’. The annual per capita availability of

Water Resources: Country profile - India

Internal Renewable Water Resources(1977-2001, in cubic km)

India Asia

(excl.

Middle

East)

Surface water produced internally 1222 10985

Groundwater Recharge 419 2472

and surface water) 380 2136

(surface water + groundwater - overlap) 1261 11321

Per capita IRWR, 2001 (cubic meters) 1211 3241

Total, 1977-2001 (cubic km) 1897 X

Per capita, 2002 (cubic meters per person) 1822 X

From other countries (cubic km) 647 X

To other countries (cubic km) 1307 X

Year of Withdrawal Data 1990

Total withdrawals (cubic km) 500 X

Withdrawals per capita (cubic m) 592 X

Renewable Water Resources 32.5 % X

Agriculture 92 % X

Industry 3 % X

Domestic 5 % X

Indian Scenario

WATER - A KEY DRIVING FORCE

76

renewable freshwater in India has fallen from around 5,277

cubic meters in 1955 to 2,464 cubic meters in 1990. Given the

projected increase in population by the year 2025, the per capita

availability is likely to drop to below 1,000 cubic meters i.e., to

levels of water scarcity. If per capita water availability is any

indication, ‘water stress’ has just begun to show in India.

As per the estimation of the National Commission for

Integrated Water Resources Development, the demand in 2010,

2025 and 2050 is likely to be 710, 843 and 1180 BCM respectively,

assuming gradually increase in irrigation efficiency to 60 %

from 35 - 40 % at present. Though water is constitutionally a

state subject, Government policies, multiplicities of activities

and economic incentives have also influenced the water

distribution and consumption across India. While the

Constitution mandates panchayats to control and manage

water at the local level, water remains under the control of a

number of ministries and institutions.

77

5

Future Scope

Functions of any area are generally linked to short-term and

long-term land use changes and have consequences on the

water resource. It has been difficult to accurately assess world

water resources and their response to the important factors

of global change, namely: climatic variability; land cover

change, industrialization and population growth; and the

control of the natural water cycle through hydraulic

engineering. Carefully maintained and reliable records of

global hydrologic change to judge the cumulative impact of

human activities on the world freshwater systems are not

available. For example, the public usually has neither any

notion about groundwater quantity nor have any

infrastructure to assess its quality at hand. The common man

judges its availability for general purposes in terms of the

depth to groundwater below the surface and quality in terms

of color, odor and taste, and thus determines their land use

characteristics. Their demands on land and groundwater and

the consequences of these demands have been characterized

scarcely. To manage with the situation, an ad hoc and tactical

approach has been taken. The regulation of groundwater

exploitation is mainly achieved through control of borehole

WATER - A KEY DRIVING FORCE

78

drilling or licensing their pumping. Due to absence of any

pricing mechanism and strict regulation, indiscriminate

groundwater exploitation, its wasteful utilization, and land

disposal of wastes continued.

Most of the hydro-geological and groundwater

development/protection research has been largely

fragmented, technocratic and relates to groundwater flow

and remediation. The research related to groundwater use

in the social and economic context being relatively small,

the research on its own is of relatively little use for practical

management purposes. Despite the highly technical work

presented in the literature, the status of knowledge of the

aquifer systems is often limited at the level at which a

management response is required. With deterioration in

routine monitoring networks in many parts of the world,

for all practical purposes, an accurate assessment is

extremely difficult. There is a need for detailed studies of

complex drainage basins that collectively represent the

domain over which anthropogenic change and its impact on

water resources and the sustainability of the biosphere can be

reasonably assessed.

To optimize the water-use in the long term, and to protect

and conserve it as required, some of the important aspects

with which water resources managers are confronted,

include characteristics of river water flow, discharges,

groundwater renewal, flow velocity and direction, its

interaction with each other as well as with surface water

bodies, the sources of pollution, trace the movement of

pollutants and containment of spreading from known

sources, quality of water and causes of quality deterioration.

These parameters must be measured under both the steady

and non-steady conditions. Efficient irrigation systems and

79

water management practices can help reduce the impact of

irrigated production on offsite water quantity and quality.

Producers may reduce water use by applying less than full

crop-consumptive requirements, shifting to alternative crops

or varieties of the same crop that use less water, or adopting

more efficient irrigation technologies. In some cases, the

effectiveness of improved practices such as irrigation

scheduling and water-flow measurement may be enhanced in

combination with other farming practices such as conservation

tillage and nutrient management.

This calls for a thorough scientific knowledge and precise

understanding of the key interaction processes of the system

with the biophysical and hydrological environment, in different

regions and within the parts of a region. Generally, studies on

regional flow systems adopted a hydraulic approach, based

on gravity-induced flow from high to low head. However,

the usual method of water level distribution analyses

provides a short-term feature of the hydraulics. Modeling

can be used to study impacts and trends resulting from

various development options, addressing and simulating not

only economic efficiency and technical merits, but also the

preferences and priorities of stakeholders. Nonetheless,

several opportunities exist for analyzing the global status

of the land phase of the hydrological cycle and associated

water resources. Scope exists therefore to “upscale” local-

scale knowledge to estimate and to develop the hydrological

and water management strategies for ecological, social and

economic sustainability over larger domains. The basin scale

is appropriate for comparing water resources (precipitation,

groundwater, surface water) and water use or water demand

(domestic, industrial, agricultural). However, the mechanisms

that govern water demand are not well outlined and relevant

parameters are yet to be suggested.

Future Scope

WATER - A KEY DRIVING FORCE

80

There remains much to do in order to obtain sound

statistics on water resources, and particularly standardized data

sets, at global level. Therefore, the methodology used to

compute water resources is intentionally simple and based on

transparent rules. More effort needs to be focused on the

assessment of the variability of water resources in space

(watershed level), in time (dry-year resources) and according

to constraints (exploitable resources). National averages hide

local differences and, for large countries, are of little use for

assessing the country’s water situation. The use of global data

sets (meteorological, etc.) coupled with water-balance models

can contribute to improving the assessment of water resources.

The emergence of improved models, high quality isotopic and

biophysical data, remote sensing imagery, information

technology, higher level of computational capability, and data

assimilation schemes, provide a unique opportunity to monitor

the state of the hydrological cycle over broad domains and in

near-real time, with a much higher spatial and temporal

resolution. In India, isotope techniques and remote sensing

have been used extensively, for over three decades, to

understand the water cycle, surface water status, soil water

movement, groundwater flow regime, recharge and

contamination characteristics, residence time (age) in the

aquifer, groundwater-surface water interactions, groundwater

hydrodynamic zones, flow-pathways and mixing processes in

groundwater system.

Emphasis is now being given also to the nature of water

as an economic resource in global debates. Yet, water tariffs in

many areas are very low for public supply and there is no

mechanism of pricing for extraction of groundwater. The level

of subsidy is extremely high for domestic consumption.

Majority thinks water is available free of cost. This leads to

more consumption and wasteful utilisation, resulting in low

81

level of revenue collection. This falls far short of covering the

cost of production and hinders the investment capacities of

the public utility. The massive investments required to avoid

pollution, remediate polluted aquifers and control overdraft

prompted the planners, developers and managers to think of

the estimates of the value of groundwater.

With an extremely uneven natural space-and-time water

resources distribution, an intensive man’s activities, and a rapid

population growth, even at the present time a significant fresh

water deficit exists in many countries and regions, especially

during dry years. In the decades to come, the most of Earth’s

population and many countries in the world would have a

critical situation with water supply. Water resources deficit

becomes a factor deteriorating the living standard of population

retarding the economic and social development in most

developing countries of the world. It is already clear that in

the first half of the 21st century the water problem will be of

the most importance even among such global problems of

humankind as food and power production. Scope exists to

cover all levels and aspects of education, information transfer

and training, a clear priority is to be given to higher education,

including institutional capacity building and networking,

education for research at postgraduate level, continuing

professional education and to activities targeting “training of

trainers”, within the domain of education and training.

The central issue is re-defining water governance. To

improve the situation alternative institutional arrangements

have to be examined along with the effective control of the

existing institutions. In the context of groundwater, there is

a need to develop management principles addressing

ecological, equity and sustainability concerns. It is also

desirable to identify, strengthen and provide legal validity to

Future Scope

WATER - A KEY DRIVING FORCE

82

local institutions, which can ensure equitable and sustainable

use of water, within ecological confines. In addition to the

Water - A Key Driving Force

Figures