S.KIRANCSE IIA

About 97% of earth's surface is covered by water.

Most animals and plants have 60-65 % water in their bodies.

An average human beings contain 45 liters of water and if he losses 2.5 to 3 liters he gets dehydration, sunstroke etc..

Exists in liquid in between 0-100 degree Centigrade.

It has highest specific heat.

It has a high latent heat of vaporization.

It is excellent solvent for several nutrients.

It has an anomalous expansion behavior. The water we use keeps on cycling endlessly through

the environment, which we call as HYDROLOGICAL CYCLE.

Human beings depend on water for almost every developmental activity. Water is used for drinking, irrigation, transportation, washing and waste disposal for industries and used as a coolant for thermal power plants.

WATER USE

WATER WITHDRAWAL WATER CONSUMPTION

WATER WITHDRAWAL: Taking water from groundwater or surface water resource.

WATER CONSUMPTION: The water which is taken up but not returned for reuse.

In 2000, about 57% of the world’s freshwater withdrawal, and 70% of its consumption, took place in Asia, where the world’s major irrigated lands are located (UNESCO, 1999).

In the coming decades, the most intensive rate of water withdrawal is expected to occur in Africa and South America (increasing by 1.5-1.6 times), while the least will take place in Europe and North America (1.2 times)

Groundwater is the water located beneath Earth's surface in soil pore spaces and in the fractures of rock formations.

About 9.86% of total fresh water resources is in the form of ground water.

It is 35-50 times that of surface water. Till some time back ground water was considered to

be pure. But later, ground water is also found to be contaminated by leachates from sanitary landfills etc.

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.

AQUIFIER:Ground water is stored in, and moves slowly

through, moderately to highly permeable rocks called aquifers. • The word aquifer comes from the two Latin words, aqua, or water, and ferre, to bear or carry. • Aquifers literally carry water underground. • An aquifer may be a layer of gravel or sand, a layer of sandstone or cavernous limestone, a rubbly top or base of lava flows, or even a large body of massive rock, such as fractured granite, that has sizable openings.

UNCONFINED AQUIFER:An unconfined aquifer is close to the land

surface, being under the direct influence of the climatic factors (precipitations mainly, but temperature also).

CONFINED AQUIFER:A confined aquifer is overlain by a

confining layer (Figure 9.2), which is generally semi-pervious, allowing vertical fluxes between the adjacent layers.

Lowering of the Water Table: Excessive pumping can lower the groundwater table, and cause wells to no longer be able to reach groundwater.

Increased Costs: As the water table lowers, the water must be pumped farther to reach the surface, using more energy. In extreme cases, using such a well can be cost prohibitive.

Reduced Surface Water Supplies: Groundwater and surface water are connected. When groundwater is overused, the lakes, streams, and rivers connected to groundwater can also have their supply diminished.

Land Subsidence: Land subsidence occurs when there is a loss of support below ground. This is most often caused by human activities, mainly from the overuse of groundwater, when the soil collapses, compacts, and drops.

Water Quality Concerns:Excessive pumping in coastal areas can cause saltwater to move inland and upward, resulting in saltwater contamination of the water supply.

Surface water is water on the surface of the planet such as in a stream, river, lake, wetland, or ocean. It can be contrasted with groundwater and atmospheric water. Non-saline surface water is replenished by precipitation and by recruitment from ground-water.

A flood is an overflow of water that submerges land which is usually dry.

Deforestation, overgrazing, mining, rapid industrialization, global warming etc. are the reasons for floods.

2014 Jammu & Kashmir Floods : Jammu and Kashmir is witnessing worst flood situation in nearly six decades due to incessant rain and flash floods. River Jhelum and its tributaries are flowing above danger mark. Nearly, 138 people have been killed so far even as the Indian Army has launched a major rescue operation and evacuated 11,000 people to safety by deploying 100 columns of troops in flood-hit areas of the state. The Vaishno Devi Yatra has also been suspended.

Drought is an extended period when a region receives a deficiency in its water supply, whether atmospheric, surface or ground water. A drought can last for months or years, or may be declared after as few as 15 days.[1] Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region.

Sushri Uma BharatiMinister for Water Resources, River Development and Ganga Rejuvenation

Prof. Sanwar Lal JatMinister of State for Water Resources,

River Development and Ganga Rejuvenation