GROUND WATER AND HYDROGEOLOGY, Study notes of Hydrogeology

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GROUND WATER AND HYDROGEOLOGY-

AN INTRODUCTION.

A PRESENTATION BY T.S. BADRINARAYANAN, GEOSCIENTIST,

B SQUARE GEO TECH SERVICES, KOLLIDAM, SIRKALI TALUK,

NAGAI DISTRICT, TAMILNADU- 609 102.

MOB- 94430 46102, E-MAIL: tsbadri56@gmail.com

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PREFACE.

PREFACE.

Water preceded all forms of life on Earth & is Water preceded all forms of life on Earth & is

believed to be the very origin of all organic like believed to be the very origin of all organic like

forms. forms.

Water is a natural resource, very much essential Water is a natural resource, very much essential

for the human & organisms. for the human & organisms.

Agriculture is the greatest user of water Agriculture is the greatest user of water

accounting for 80% of all consumptions. accounting for 80% of all consumptions.

An adequate supply of water is one of the pre An adequate supply of water is one of the pre

- -

requisites for development and industrial growth. requisites for development and industrial growth.

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FRESH WATER IS RARE!

FRESH WATER IS RARE!

Only 3% of water is fresh (< 500 ppm TDS)Only 3% of water is fresh (< 500 ppm TDS)

25% is ground water, 75% is in ice! 25% is ground water, 75% is in ice!

Less than 1% is in streams and lakes. Less than 1% is in streams and lakes.

Water is water. It Water is water. It

’’

s the stuff in the water that s the stuff in the water that

makes a difference to quality. makes a difference to quality.

Almost any water can be made drinkable. Almost any water can be made drinkable.

Desalination is increasing in use. Desalination is increasing in use.

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GLOBAL WATER RESOURCES. GLOBAL WATER RESOURCES.

Distribution of Water

Distribution of Water

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BASICS OF HYDROGEOLOGY. BASICS OF HYDROGEOLOGY.

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HYDROGEOLOGY.

HYDROGEOLOGY.

The branch of Geology dealing with

The branch of Geology dealing with

surface & subsurface water

surface & subsurface water

[ground water]. [ground water].

The science of hydrogeology is

The science of hydrogeology is

defined as hydrology with emphasis

defined as hydrology with emphasis

on geology.

on geology.

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WATER SOURCES.

WATER SOURCES.

Water Sources Water Sources

Surface WaterSurface Water



Streams Streams



Lakes Lakes



Runoff Runoff

Ground WaterGround Water



Wells Wells



Springs Springs

 

Ganats Ganats

Rain HarvestingRain Harvesting

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GROUND WATER.

GROUND WATER.

Ground water Ground water

All the water contained in the All the water contained in the

void spaces within rocks. void spaces within rocks.

Merriam Merriam

Webster dictionary: Water within Webster dictionary: Water within

the earth, especially water that supplies wells the earth, especially water that supplies wells

and springs. and springs.

EPA

EPA

s drinking water glossary: The water s drinking water glossary: The water

that systems pump and treat from aquifers that systems pump and treat from aquifers

(natural reservoirs below the earth's surface). (natural reservoirs below the earth's surface).

More inclusively, it includes soil moisture, More inclusively, it includes soil moisture,

permafrost, water in tight formations, saline permafrost, water in tight formations, saline

waters, etc.. waters, etc..

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ORGIN OF GROUND WATER. ORGIN OF GROUND WATER.

Some of precipitation ie, rain water soaks

Some of precipitation ie, rain water soaks

into the land surface by the process of

into the land surface by the process of

infiltration and percolates down to the

infiltration and percolates down to the

water table to become ground water.

water table to become ground water.

Water becomes ground water

Water becomes ground water

by by

infiltrating through soil

infiltrating through soil

Infiltrating through faults or fractures

Infiltrating through faults or fractures

flowing directly into karst sinkholes

flowing directly into karst sinkholes

or caverns

or caverns

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ORGIN OF GROUND WATER. ORGIN OF GROUND WATER.

PRECIPITATION.INFILTRATION

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GROUND WATER IN GROUND WATER IN

HYDROLOGIC CYCLE.

HYDROLOGIC CYCLE.

Groundwater in Hydrologic Cycle

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HYDROLOGIC CYCLE.

HYDROLOGIC CYCLE.

Thousands of km

3

/yr

Hydrologic Cycle Hydrologic Cycle

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OCCURRENCE OF OCCURRENCE OF

GROUND WATER.

GROUND WATER.

Nature does not provide ground water at the Nature does not provide ground water at the

place of our choice. It occurs in the subsurface place of our choice. It occurs in the subsurface

in certain favorable geological formations & in certain favorable geological formations &

structures. structures.

Aquifer : Aquifer :

aqui means water; fer means to bear aqui means water; fer means to bear

thus an aquifer bears water from voids thus an aquifer bears water from voids

a a

saturated permeable geologic unit that can saturated permeable geologic unit that can

transmit significant quantities of water under transmit significant quantities of water under

ordinary hydraulic gradient ordinary hydraulic gradient

eg eg

sand stone, sand stone,

sand & gravel sand & gravel

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OCCURRENCE OF OCCURRENCE OF

GROUND WATER.

GROUND WATER.

Aquiclude Aquiclude

a saturated geologic unit that is a saturated geologic unit that is

incapable of transmitting significant quantities of incapable of transmitting significant quantities of

water under ordinary hydraulic gradient water under ordinary hydraulic gradient

eg eg

clay lenses & shale. clay lenses & shale.

Aquitard Aquitard

: less permeable beds in a : less permeable beds in a

stratigraphic sequence stratigraphic sequence

eg eg

clay lenses clay lenses

interbedded with sand interbedded with sand

Aquifuge Aquifuge

has too low porosity and neither has too low porosity and neither

absorbs nor transmits water absorbs nor transmits water

eg eg

dense basalt, dense basalt,

granite. granite.