Water Resources

Global Environment Awareness

Water resources : Use and over-Utilization of surface and ground water,floods, drought, conflicts and water, dams-benefits and problems.

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Table of Contents

1. Water – The Definition2. Water Forms and Distribution3. Types of Water Uses 4. Water Availability5. Fresh Water Shortage6. Water Use Problems and Conflicts7. Increase Water Supply 8. Floods9. Drought

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1. Water – The DefinitionWater is a marvelous substance which

can be beautiful, powerful and destructive.

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1.1. Water Physical AttributesWater is found in three states

Liquid

Solid Gas

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1.2. Hydrologic Cycle

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2. Water Forms and Distribution

About 71% of the earth’s surface is covered with water.

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2. Water Forms and Distribution

Source: Environmental Science – A Global Concern,

Water Use and Management

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2.1. OceansIs the largest area and volume of

water. Contain more than 97% of the earth’s

water.

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2.2. Ice and SnowContain almost 90% of freshwater. Is as much as 2km thick. Situate mostly in Antarctica (85%),

Greenland (10%), and other snow mountain (5%).

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2.3. GroundwaterGroundwater is water in the rock and

soil layer beneath Earth’s surface. Absorb excess runoff rain and snow on

ground. Return to lakes, streams, rivers and/or

marshes. Is readily available for use and

drinking.

Tapping Groundwater

Benefits:Year-round useNo evaporation lossesOften less expensive

Potential Problems:• Water table lowering – too much use

• Depletion – • Saltwater intrusion – near coastal areas

• Chemical contamination• Reduced stream flows

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2.4. LakesLakes are created from variety of

geological events

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2.4. Lakes (cont.)Freshwater lakes

Contribute 91,000km3 (about 0.007% of total Earth’s water)

Provide water for agricultural irrigation, industrial processes, municipal uses and residential water supplies.

Major freshwater lakes: Caspian Sea (Central Asia), Baikal Lake (Russia), Tanganyika Lake (Eastern Africa), Lake Superior (U.S), and Malawi Lake (Eastern Africa)

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2.4. Lakes (cont.)Saline lakes

Possess 85,000km3 (about 0.006% of total Earth’s water)

Saline lakes’ water cannot be used due to high salinity.

Major saline lakes: Caspian Sea (Central Asia), The Great Salt Lake (U.S.), The Dead Sea (between Jordan & Israel), and Aral Sea (between Kazakhstan and Uzbekistan).

The Great Salt Lake

The Dead Sea

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2.5. Rivers and StreamsRivers and streams are bodies of flowing

surface water driven by gravity. Rivers and Streams contain only 2,120km3

(about 0.6% of liquid fresh water surface and around 0.0002% of the Earth’s water.)

Source: Environmental

Science – A Global

Concern, Water Use and Management

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2.6. Wetlands and Soil MoistureWetland are areas of land where water

covers the surface for at least part of the year.

They are not as important as lakes and rivers for water storage.

However, they play vital roles in: Erosion protection Flood reduction Groundwater replenishment Trapping nutrient and sediment Water purification Providing fish and wildlife habitat

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5.7. AtmosphereAtmosphere contains about 0.001% of

total Earth’s water. It is around 4% of air volume in the

atmosphere. Movement of water through atmosphere

provide mechanism for distributing freshwater to terrestrial reservoir (in form of rain, snow, hail…).

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3. Water UsesOff-Stream Uses

Agriculture Thermoelectric Industrial Mining Domestic Commercial

In-Stream Uses Hydropower Navigation Recreation Ecosystem Support

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3.1. Off-Stream UsesAgricultureThermoelectricIndustrialMiningDomesticCommercial

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a. AgricultureIrrigation

Crop irrigation consume 2/3 of water withdrawal.

Evaporation and seepage from unlined irrigation systems are the principal water losses.

There are three types of irrigation systems:

Flood Irrigation Sprinkler Irrigation Drip Irrigation

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a. Agriculture (cont.)Livestock

Watering livestock Dairy operation Cooling livestock facilities Dairy sanitation and clean-up Animal waste disposal

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a. Agriculture (cont.)Aquaculture

Raising fish. Raising shellfish. Raising shrimp and lobster. Raising other creatures living in water.

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b. ThermoelectricWater is used in

production of electrical power.

Thermoelectric is one of the largest uses of water In 2005, it consumed about

201,000 million gallons of water each day.

Both freshwater and saline water are used in thermoelectric.

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c. IndustrialIndustries need water to cool down their

machinery to a temperature that allows the manufacturing process to keep going.

Water is also needed to clean machinery, products, and buildings.

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d. MiningWater is used for the extraction of

minerals that can be in forms of: Solid: coal, iron, gold, sand – etc. Liquid: crude oil. Gas: natural gases.

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e. DomesticDomestic water use is the consumption

for household purposes – both indoor and outdoor.

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f. CommercialWater is used in businesses such as

hotels, restaurants, marketplaces, and so on.

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3.2. In-Stream UsesHydropower Recreation

Navigation Ecosystem Support

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4. Water Availability

Source: Environmental Science – A Global Concern, Water Use and Management

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4.2. Water Stress & Water ScarcityWater Stress:

Annual water supplies is less than 1,700m3 per person.

Water Scarcity: Annual water supplies

is less than 1,000m3 per person.

Absolute scarcity: Annual water supplies

is less than 500m3 per person.

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5. Fresh Water Shortage Fresh Water Shortage is due to:

Population growth Lack of access to clean water Groundwater is being depleted Climate change / global warming Rivers and lakes are shrinking

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1983

2007

10 year drought in the Colorado

River basin.

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6. Water Use Problems and Conflicts Water Overuse

Overuse in agriculture Overuse in residence Overuse in community

Some interesting facts:Water needed to produce our daily food:

40 liters to produce 1 slice of white bread. 70 liters to produce 1 apple. 1,300 liters to produce 1kg of wheat. 3,400 liters to produce 1kg of rice. 3,900 liters to produce 1kg of chicken meat. 15,500 liters to produce 1kg of beef.

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6. Water Use Problems and Conflicts Water Conflict

Control of Water Resources: where water supplies or access to water is at the root of tensions.

Military Tool: where water resources, or water systems themselves, are used by a nation or state as a weapon during a military action.

Political Tool: where water resources, or water systems themselves, are used by a nation, state, or non-state actor for a political goal.

Terrorism: where water resources, or water systems, are either targets or tools of violence or coercion by non-state actors.

Military Target: where water resource systems are targets of military actions by nations or states.

Development Disputes: where water resources or water systems are a major source of contention and dispute in the context of economic and social development

Conflicts over waterConflicts over control of shared river basins

Billion people lack access to safe water and 2.4 billion lack access to sanitation

More than 6000 children die every day because of diseases associated with water

On flush of the western toilet uses as much water as one person for whole day of washing , drinking etc

FLOODS

Click icon to add picture

Change in the course of a river

Wrong design of a dam, or a canal

Deforestation

Types of floods

Flooding can be divided into different categories according to their duration:Slow-Onset FloodsRapid-Onset FloodsFlash Floods

Slow-Onset Floods

Slow-Onset Floods usually last for a relatively longer period, it may last for one or more weeks, or even months. As this kind of flood last for a long period, it can lead to lose of stock, damage to agricultural products, roads and rail links.

Rapid-Onset Floods last for a relatively shorter period, they usually last for one or two days only.

Although this kind of flood lasts for a shorter period, it can cause more damages and pose a greater risk to life and property as people usually have less time to take preventative action during rapid-onset floods.

Rapid-Onset Floods

Flash Floods

Flash Floods may occur within minutes or a few hours after heavy rainfall, tropical storm, failure of dams or levees or releases of ice jams. It causes the greatest damages to society.

Coastal FloodsArroyos FloodsRiver FloodsUrban Floods

Flooding can also be divided into different categories according to their location:

Coastal Floods

Coastal Floods usually occur along coastal areas. When there are hurricanes and tropical storms which will produce heavy rains, or giant tidal waves created by volcanoes or earthquakes, ocean water may be driven onto the coastal areas and cause coastal floods.

Arroyos Floods

A arroyo is river which is normally dry. When there are storms approaching these areas, fast-moving river will normally form along the gully and cause damages.

This is the most common type of flooding. When the actual amount of river flow is larger than the amount that the channel can hold, river will overflow its banks and flood the areas alongside the river. And this may cause by reasons like snow melt or heavy spring rain.

River Floods

In most of the urban area, roads are usually paved. With heavy rain, the large amount of rain water cannot be absorbed into the ground and leads to urban floods.

Urban Floods

Flood prone areas

These areas suffer the most from floods.

In Bangladesh, 110 million people live unprotected on the flood plains of southern Asia’s most flood prone river system.

Flood generally affect more than 30% of the total land area in Bangladesh.

Low lying parts of active flood plains and river Esturies

They are subjects to flash floods. These also occur in narrow valleys and heavily developed urban settings with rapid run off.

Small Basins

Floods resulting from failures are examples of combined natural and technological hazards.

As they are prone to flash floods, opportunities for warning evacuation are limited.

Areas below unsafe dams

The Indian Experience

•India experiences more floods than any other country.•About one-eighth of the total area of the country is prone to floods.•Floods damage the standing crops and take a heavy toll of life and property.

Flood Forcasting

•This involves giving prior information regarding floods.•This is essential so that timely action can be taken to prevent loss of life.

Flood Forcasting

•The flood forecasting techniques are constantly reviewed, updated and modernized to make forecasts more accurate.•This will reduce the miseries suffered by the people from recurring floods.

Destruction by FloodsFloods can cause major structural damage

to buildings, kill plants and animals, destroys habitats, and removes soil.

Floods cause many deaths and drown many plants and crops, and hundreds of millions of dollars in damage.

Many nutrients in topsoil are brought downstream or deposited in the ocean.

Control of floods(i) Various preventive measures are proper embankment of water bodies, building check dams on flood-prone streams, prohibiting cultivation in flood plain of rivers and growing forests and perennial trees, interlinking of river of the country and constructing houses on raised platforms and supported by reinforced stilts.(ii) Floods can be controlled by collecting data from meteorological department and alerting the people of affecting area.(iii) Educating the people about the steps to be taken in the event of disaster.(iv) Hill slopes and catchment areas of rivers must be afforested and reforested

DroughtLack of moisture for an extended period of

time which in turn causes deficient moisture in the soil.

Degree of deficiency Time period Size of area affected.

Droughts unlike floods are not a distinct eventDrought has no well defined start or endThe effect of drought vary by affected sector

or different groups.

Types of droughtMetrological:

When an area received reduced precipitation (rain) duration or intensity

Types of droughtHydrological:

Deficiencies in the surface and subsurface water supplies

It is measures as lack in the reservoir and lake levels

Types of droughtAgricultural

When there is inadequate soil moisture to meet the needs of a particular crop

Results in Low plant development. Low yield,

Types of droughtSocioeconomic:When the physical water shortages

start affecting the health, well being and quality of life of the people

How is drought different?It is a slow natural hazard, may linger

on for yearsDrought effects large geographic areaIt is both natural (disruption of

global circulation of atmosphere and social event

What Causes Droughts?Droughts are caused

by a lack of precipitation in an area resulting from weak or less frequent storms and other weather systems

Most major droughts last for months or years.

Where Do Droughts Occur?

Destruction by Droughts.Droughts cause major damage to crops

and animals, especially if they occur during the region’s growing season.

During a drought not enough water is provided to support living things. Crops can decrease 10%-20% during a drought.

Droughts affect reservoirs, water supplies, water tables, and topsoil. Water levels drop, and topsoil becomes dry and less favorable to plants.

Areas that are in a drought are more likely to have wildfires than other regions.

How Often Do They Occur?

Droughts can occur anytime of the year.

Near the equator, regions may experience 2 or more droughts per year.

Weather That Causes Droughts.Droughts occur when weak or less

frequent rainfall occurs than normal.During a drought not only is there little

rainfall, but the moisture from the soil also leaves into the atmosphere through evaporation and transpiration.

Control of DroughtControl Measures(i) Rain water harvesting and canal irrigation.(ii) Improvement of agricultural practices like dry land forming to conserve water in drought prone areas.(iii) Stopping paddy cultivation in areas of water scarcity and growing drought resistant variety of crops.(iv) Promoting social forestry and wasteland reclamation, growing species according to the ecological requirements of the area.(v) Supplying food, fodder and water to drought-hit people and their rehabilitation with all essential requirements of life.

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DamsA dam is a barrier

that impounds water or underground streams. Dams generally serve the primary purpose of retaining water.

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Positive impact of Dams The dams have tremendous potential

for economic upliftment and growth.They can help in checking floods and

famines, generate electricity and reduce water and power shortage.

Provide irrigation water to lower areasProvide drinking water in remote areas

and promote navigation, fishery etc.

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Hydroelectric powerAdvantages of hydroelectric power

  Disadvantages of hydroelectric power

     

      (i) It is a pollution free and renewable source of energy.

      (ii) Its operational cost is low.      (iii) It helps in checking

floods and the stored water can be used for irrigation, fisheries, drinking water and for recreational (eg, boating, water sports) purposes.

        

(i) There is problem of planning and construction of dams at suitable sites.

      (ii) Construction of dams may change the topography of an area and may harm local flora and fauna.

      (iii) Dams can block routes of fish migration required for their survival and reproduction.

      (iv) There is problem of silting of water reservoirs of dams due to soil erosion of catchment areas, particularly, by their deforestation.

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Negative impacts of dams The most significant environment effect of

dams results from the displacement of human populations.

Dams and reservoirs change sediment deposit in rivers.

They can be habitat loss, erosion and declining water quality.

Loss of forests, flora and faunaChanges in fisheries and the spawning groundsSiltation and sedimentation of reservoirsStagnation and water logging near reservoir

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Effects Of Dams On Forests And Tribal People

Reservoir induced seismicity (RIS) causing earthquakes

Growth of aquatic weeds.Reduced water flow and slit deposition in

riverFlash floodsSalt water intrusion at river mouth Loss of land fertility along the river since

the sediments carrying nutrients get deposited in the reservoir

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Negative impact of Dams

But the negative socio-economic impacts of damsEndangered livelihoods :The disruption of natural

ecosystems, particularly of floodplains, threatens the livelihoods of the millions of people who depend on fisheries, wetlands, and regular deposits of sediment for agriculture.

Displacement of people: An estimated 40 to 80 million people have been displaced by dams worldwide. Big river valley projects like Hirakund dam (Orissa) Bhakra Nngal dam (Punjab), Tehri dam (Uttaranchal), Sardar Sarovar Project (Gujarat) and Damodar Valley project (West Bengal) etc., have caused large scale displacement of local people. In the last 50 years more than 20 million people have been displaced by dams.

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Effect of DamsHealth: Improved access to clean

water is a major benefit of dams. But the habitat they create is perfect for disease-carrying mosquitoes and snails, which bring illnesses such as malaria and schistosomiasis.

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Effect of DamsDamage to cultural heritage sites:

In many places, large dams have impacted cultural heritage by the submergence and destruction of cultural resources such as shrines, buildings, artifacts, burial sites, and sacred landscapes.

 

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CONSERVATION/MANAGEMENT OF WATER

Conservation of water resources. For conservation and management of fresh water, following methods can be employed

      1. Reducing agricultural water wastage by increasing efficiency of irrigation system.

      2. Afforestation and protection of watersheds to improve economy.

      3. Formation of artificial clouds, so that a change can be brought in the atmosphere.

      4. Changes in the vegetation of a particular area, so that even in the dry season maximum amount of water can be stored. In addition to this, dams should be constructed to stop the drainage of rain water.

     

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CONSERVATION/MANAGEMENT OF WATER

      5. Control the distribution of water by constructing big dams.

      6. Desalinization of sea water and saline ground water.

      7. Proper utilization of underground water.

     8. Melt the glaciers and snow for using as a fresh water resource.

      9. Regular de siltation of water bodies