WATER RESOURCES
• Water resources are sources of water that are useful to humans.
• Uses of water include agriculture, industrial, constructions , household, recreational and environmental activities. All of these humans uses fresh water.
• 97% of water on the earth is salt water and only 3% is fresh water.
• Freshwater is a renewable resource, yet the world’s supply of clean, fresh water is steadily decreasing. Because, demand for water exceeds supply in many
• With the growth of the human population, there is an increasing need for larger amounts of water to fulfill a variety of basic needs.
• Today in many areas, it cannot be met.
• The over-utilization of water occurs at various levels.
• Most people use more water than they really need. Most of us waste water during a bath by using a shower or while washing clothes.
• The per capita use of water in a family of four members in the USA is 1000 Cubic Metres which is = 1000000 Litres per year many times more than in the developing countries.
• Many agriculturalists use more water than necessary to grow crops.
• There are many ways in which farmers can use less water without reducing yields such as the use of drip irrigation systems.
• It is important to realize what the long term effects of overutilization of water are and to understand how we could prevent major damages.
• Ground Water: is the portion of the Earth’s water cycle that flows underground. Groundwater originates from precipitation that percolates into the ground. Percolation is the flow of water through soil and porous rock.
• Sustainable Development: According to The World Commission on Environment and Developmental Act, 1987) is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
Overutilization of Surface and Groundwater
Water is among the most precious of natural resources.
The water coming through precipitation when it does not percolate down into the ground will be in the form of streams, lakes, ponds, wetlands, etc. which is known as surface water.
This surface water is largely used for public water supply, irrigation, industrial use, river water and sea water are also used for transportation and often unfortunately for the purpose of disposal of wastes
In many regions of the world, the pressures of economic development and overpopulation are producing a surface-water scarcity which is both in terms of quantity and quality.
In most places, groundwater can be found within a relatively short distance below the ground surface.
The seemingly abundant supply of groundwater has led to its indiscriminate and sometimes excessive use. However, this use can have diverse and often wide ranging effects on the local and regional hydrology and ecology as groundwater often supports the water supply to streams, wetlands, etc., and so their deple
These interdisciplinary aspects of groundwater utilization have brought into question the concept of safe yield, defined as the maintenance of a long-term balance between the rate of withdrawal and the rate at which groundwater can be naturally recharged by the precipitation and percolation which is specific to each area.
A region’s ground water should be exploited without unduly compromising the principle of sustainable development.
a) Basically flood is when the water level in an area rises where there was normally little of none before.
b) Floods can be dramatic and quick or slow and creeping.
c) Floods are natural phenomena common in many places around the world where either there is river nearby or the local weather can dump large amounts of rain
Causes of floods:
Heavy rainfall often causes floods in the low lying coastal areas.
Prolonged downpour can also cause the overflowing of lakes and rivers resulting into floods. Deforestation of catchments of rivers leads to heavy runoff of soil which settles down at the bottom of the rivers raising the river bed and causing more frequent floods
Human activities have contributed largely to the sharp rise in the incidence of floods, which otherwise is a natural disaster. For mining activities, a land has to be cleared of all vegetation and then dug up. This causes the possibilities of flooding.
Researchers have found that if global temperatures increase by 2 degrees Celsius (3.6 Degrees Fahrenheit), then large floods that occurred about once every 100 years could occur up to 5 times more in mountainous regions as here run off rates is supposed to be significantly affected by temperature
Unplanned urbanization leads to land surface covered by the construction with very little open space to allow for percolation of water. The result is that even moderate rainfall can cause floods.
Dams are a reason for floods when excess water pressure on dams during rains has to be eased by opening the floodgates.
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