WATER RESOURCES

Presented by VIJAY JRF Gandhi Institute of Technology.

Introduction

• Water resources are sources of water that are useful or potentially useful.

• Uses of water include agricultural, industrial, household, recreational and environmental activities.

• Virtually all of these human uses require fresh water.

A graphical distribution of the locations of water on Earth

A graphical distribution of the locations of water on Earth.

Fresh Water

• Fresh water is a renewable resource, yet the world's supply of clean, fresh water is steadily decreasing.

• Water demand already exceeds supply in many parts of the world and as the world population continues to rise, so too does the water demand.

How people use

water

resource?

Household use:

ways

Wash the garden.

Turning off the fire.

Wash dirty dishes

Wash the car.

Personal use:

ways

To drink water, when you’re driving bicycle.

Take a shower

Recreational use:

ways

Play in the beach.

Go to the pool.

Fishing

Surf

Uses of water

Uses of Fresh Water

Types

Agricultural: The 69% of water is use for irrigation. Irrigation in some areas is necessary for crops grow.

Aquaculture: is a small agricultural growing.

Industrial: The 15% of water is use for industrial things. The major use of industrial is power plants. Oil refineries which is use with a chemical process. Manufacturing plants which use water as a solvent.

Industrial water is lower than agricultural water.

Household: The 15% of water is use for household. Household uses are:

Drinking

Bathing

Water

Cooking

Sanitation

Gardening

Recreational: Recreational water has a small use. Recreational use is mostly needed for reservoirs. This type of use of water is specific for places and good times.

Environmental water has a small use. Environmental water is use mostly for:

Artificial wetlands

Artificial lakes

This is to create a wildlife habitat.

Water Resources-Use and Overutilization

• The water Cycle through evaporation and precipitation, maintains hydrological systems

• All aquatic ecosystems are used by a large number for their daily needs such as washing irrigation, cooking etc.

• One of the greatest challenges today is the management of these water resources.

• Due to increasing population there is an enormous supply for the available freshwater resources.

• India is likely to face water crisis by 2025. • With growth of human population larger amounts of water will be

required to fulfill basic needs Today in many areas this need cannot be met.

• Overutilization of water occurs at various levels: • Most people use more water than required to carry out basic

activities such as brushing, bathing, washing and cleaning etc. • Farmers also sometimes use double the water required for

irrigation. • There are many ways in which the farmer can increase the yield by

using less water for irrigation.

Sources of fresh water

•Sources of Fresh Water •Surface Water is water in a river, lake or fresh water wetland. •Surface water is naturally replenished by precipitation •naturally lost through discharge to the oceans, evaporation, and sub-surface seepage.

•Sub-Surface water or groundwater •One of our most valuable resources is the water beneath our feet. • groundwater is fresh water located in the pore space of soil and rocks. • It is also water that is flowing within aquifers below the water table. •Sometimes it is useful to make a distinction between sub-surface water that is closely associated with surface water and deep sub-surface water in an aquifer (sometimes called "fossil water").

An aquifer is an underground formation of permeable rock or loose material which can produce useful quantities of water when tapped by a well. Aquifers come in all sizes. They may be small, only a few hectares in area, or very large, underlying thousands of square kilometers of the earth's surface. They may be only a few meters thick, or they may measure hundreds of meters from top to bottom.

How Much Do We Depend On Groundwater? According to United States Geological Survey (USGS) figures, groundwater provides an estimated: 22% of all freshwater withdrawals 37% of agricultural use (mostly for irrigation) 37% of the public water supply withdrawals 51% of all drinking water for the total population 99% of drinking water for the rural population

FLOODS

FLOODS ARE NATURAL PHENOMENA.

FLOODS ARE WATER RELATED DISASTER

A flood occurs when the Geomorphic Equilibrium in

the river system is disturbed because of intrinsic or

extrinsic factors or when a system crosses the

geomorphic threshold.

(a) Flooding in a river due to aggradation of river bed

(intrinsic threshold);

(b) Flooding in a river due to heavy rainfall (extrinsic

threshold)

TYPES OF FLOODS

Types of floods •Flash floods

•River floods

•Coastal Floods

•Urban Flood

According to their duration flood can be

divided into different categories: •Slow-Onset Floods: Slow Onset Floods

usually last for a relatively longer period, it

may last for one or more peeks, or even

months.

•Rapid-Onset Floods: Rapid1Onset Floods

last for a relatively shorter period, they

usually last for one or two days only.

•Flash Floods: Flash Floods may occur within

minutes or a fe1w hours after heavy

rainfall, tropical storm, failure of dams or

levees or releases of ice dams. And it causes

the greatest damages to society.

Contd….

Floods

Natural

Storm Surge,

Tsunami, Glacial Melt,

Landslide, Riverine,

Estuarine & Marine Flood

Eg: bursting of landslide blockades in the catchment

areaof the Bhagirathi River in August 1978 (Gupta and Dave,

1982).

Man made

Breach of

Dam/ Barrage/

Embankment

Release from Reservoir,

Urban Flood

Eg: In the year 2009,Almatti and Naryanpur dams on the Krishna River in Karnataka. This water along with rain

water reached Andhra Pradesh near the Srisailam dam. It

causes a hevy floods in andhrapradesh

7/4/2015 19 Floods- Disaster Managment

Causes for flood

FACTORS

VEGETATION COVER

This varies seasonally. The type and

amount will affect interception and

stemflow/throughfall. Overland flow is

reduced. Lag time will be increased.

ROCK TYPE

Impermeable rocks prevent groundwater

flow and encourage through flow and

overland flow. These rocks will decrease

lag time. Permeable rock will have the

opposite effect.

LAKES & RESERVOIRS

These will store floodwater and

thus reduce lag time and control

river response to heavy rainfall.

SOIL TYPE & DEPTH

Deep soils store more

water, pipes in the soil

encourage through flow.

Soils with small pore

spaces will reduce

infiltration and increase

overland flow.

LAND USE

Impermeable surfaces

created by urbanisation will

reduce infiltration and

encourage overland flow.

Different types of crops

affect interception rates e.g.

cereals 7-15%.

RAINFALL INTENSITY & DURATION

Intense rain will increase overland

flow and reduce lag times. Gentle

rain over a longer time will allow

more infiltration.

SLOPES

Steep slopes will encourage

overland flow and gentle

slope will slow run off down.

CLIMATE

The distribution of rainfall over the

year and the temperatures will

affect the lag times.

FLOODS IMPACTS

• Human Loss

• Property Loss

• Affects the Major Roads

• Disruption of Air / Train / Bus services

• Spread of Water-borne Communicable Diseases

• Communication Breakdown

• Electricity Supply Cut off

• Economic and Social Disruption

• Increase in Air / Water Pollution

7/4/2015 Floods- Disaster Managment 22

Analysis over years

Drought

• Rains are very unpredictable. This leads to periods where there is serious scarcity of water.

• Drought prone areas are faced with irregular periods of famine as farmers have no income.

• Drought prone areas Development Programs: • Under this scheme, people are given wages in bad

years for activities like building roads, minor irrigation works and plantation programs.

• It is a major problem in arid and semi arid regions. • Drought affects home, agriculture, industry, leads to

malnutrition problems in children due to food shortages

• Major factor responsible for drought is deforestation.

• Due to denuded forest cover the rainwater rushes down the river and is lost.

• Forest cover permits the water to remain in the same area and gradually seep into the ground.

• This charges the underground stores of water in natural aquifers. Which later can be use during the period of no monsoons.

Causes of drought

Natural / Physical causes: - Weather: increased amount of

anticyclone weather (hot + dry) means air holds less moisture so you get less rain

- Global warming: weather patterns change (e.g. Sahel is becoming hotter + drier)

- Hotter weather = more evaporation than precipitation

- El Nino: random weather event that reverses normal weather patterns (e.g. Australia has years of drought + then years of flood)

Human causes: - Overpopulation: too many people

living in an area using too much water

- Overcultivation: planting too many crops which use up too much water

- Overextraction: removing too much water from wells so they dry up

- Deforestation: cutting down trees which otherwise store water + hold soil together

- Politics: fighting over water, or companies being greedy + taking too much water to then sell on

Conflicts over Water

Scarcity of water has increased conflicts over water among various states and countries. Some water conflicts are:

1. Indus water dispute.

2. Ganga water dispute.

3. Cavery water dispute.

4. Yamuna water dispute.

Conflicts over water

• Multiple conflicts between countries. • Around 20 major cities in India face chronic or interrupted

water shortages. • Around 100 countries all around the world share the waters of

13 large rivers and lakes. • The upstream countries could stare the downstream countries

leading to political instability. Eg. Ethiopia (Upstream) and Egypt (Downstream) are highly dependent on the river Nile for their water supply.

• International accords that look at fair distribution of water will become critical to the world peace

• India and Bangladesh already have a pact for fair usage of water of Ganges River.

DAMS – Introduction

• There are more than 45000 dams all around the

world, which play an important role in in

communities and economies that harness these

water resources for economic development.

• 30-40% of the irrigated land worldwide relies on

dams.

Water Supply Navigation

Irrigation

Benefits of Dams

Recreation

Flood Control Waste Impoundment

Power Supply

Dams Problems

• Fragmentation and physical transformation of rivers

• Impacts on riverine ecosystems

• Social consequences of large dams due to displacement of people.

• Water logging and salinization of surrounding land.

• Dislodging animal population.

• Disruption of fishing and waterway traffic.

EFFECT ON ENVIRONMENT

• Greenhouse gas emissions

The reservoirs of power plants in tropical regions may produce substantial amounts of methane, carbon di oxide. This is due to plant material in flooded areas decaying in an anaerobic environment, and forming methane, a very potent greenhouse gas.

• Soil Erosion

One of the first problems with dams is the erosion of land. Dams hold back the sediment load normally found in a river flow, depriving the downstream of this. In order to make up for the sediments, the downstream water erodes its channels and banks. This lowering of the riverbed threatens vegetation and river wildlife. One of the reasons dams are built is to prevent flooding. However, most ecosystems which experience flooding are adapted to this and many animal species depend on the floods for various lifecycle stages, such as reproduction and hatching. Annual floods also deposit nutrients and replenish wetlands.

Contd- Species Extinction

As fisheries become an increasingly important source of food supply, more attention is being paid to the harmful effects of dams on many fish and marine mammal populations. The vast majority of large dams do not include proper bypass systems for these animals, interfering with their lifecycles and sometimes even forcing species to extinction.

Changes to Earth's Rotation

NASA geophysicist Dr. Benjamin Fong Chao have found evidence that large

dams cause changes to the earth's rotation, because of the shift of water weight from oceans to reservoirs. Because of the number of dams which have been built, the Earth's daily rotation has apparently sped up by eight-millionths of a second since the 1950s. Chao said it is the first time human activity has been shown to have a measurable effect on the Earth's rotation.