WATER RESOURCES

Water is an indispensible natural resource.

More than 97% of the Earth is covered with water, but only little over 3% is fresh water.

Water we use keeps on cycling endlessly through the environment which is called ‘Hydrological cycle’.

Water Resources Solar energy drives the water cycle. Plants also play a role in this by

absorbing the groundwater from the soil and releasing it into the atmosphere by the process of transpiration.

Excess water usage has resulted in depletion of ground water reserves.

Rising incidents of floods has been due to rapid industrialization, deforestation and urbanization.

Iceberg and Polar cap store most of the fresh wateron Earth

Scarcity of fresh water

On a global basis, fresh water is a increasingly scarce resource. It is partially caused by increasing population coupled by change of consumption pattern and climate changes.

Competing water uses (I)

Threats to fresh water resources Climate change causes change in

frequencies of droughts and floods. Depletion of aquifers caused by over-

consumption as a result of population growth.

Pollution and contamination by sewage, agricultural and industrial runoff.

Distribution of population and water resources

Desalination of sea water as fresh water supply

Desalination of sea water can be done either via distillation or membrane process.

Both process requires large amount of energy and thus costly, which means desalination remains an expensive option for providing reliable fresh water supply, restricted to only economically well-off countries.

Although people starting building dams thousands of years ago, technology for large dams didn’t evolve until the 19th century

Today…. 60% of the world’s rivers are dammed There are ~ 45,000 large dams (>15m high) and over 1500 under

construction There are ~ 800,000 smaller dams Volume: 10,000 km3 (5x vol of all river water)

Advantages of DAM

Regulate water flow and Flood ControlDrought ControlTime for endangered species to be

movedTo another suitable location.IrrigationNavigation ImprovementGeneration of hydro-electric power

Environmental Issues Dams change the chemical, physical and

biological processes of river ecosystems. They alter free-flowing systems by

reducing river levels blocking the flow of nutrients, changing water temperature and oxygen

levels, preventing fish and wildlife migration.

CVEN 5838 Aug 26, 2008

Dam failures have killed thousands and cost billions

CVEN 5838 Aug 26, 2008

Mineral ResourcesMinerals are naturally occurring organic or

inorganic solids with definite chemical composition and physical properties.

They are used in:a) Industrial Developmentb) Generation of energyc) Constructiond) Transportatione) Communicationf) Medicinalg) Formation of alloys

Mineral ResourcesSome of the common minerals in India are:1. Energy generating mineralsa) Coal and ligniteb) Uranium2. Other commonly used mineralsa) Aluminiumb) Ironc) Copperd) Micae) Gold and other precious / bullion metals

Mineral ResourcesExcess mining for minerals has resulted

in:a) De-vegetation and defacing landscapeb) Groundwater contaminationc) Surface water pollutiond) Air pollutione) Occupational health hazardsf) Soil Erosion