Availability of water on earth:
If we look at the pictures of earth from space, we can see the earth looking blue, brown and green.
About 71% of the earth’s surface is filled with water yet only a small percentage of this water is available for use.
Water can be seen around us in all the three states of matter. Ice is the solid state, water is the liquid state and vapor is the gaseous state. The water on the earth keeps on transforming between the three states in a cycle. This is known as the water cycle. The water cycle helps in keeping the amount of water on the earth a constant.
Following are the main steps of water cycle in nature:
Evaporation: Water on the surface of the earth gets evaporated and turns into vapor. The water vapor also comes from plants as a byproduct of their transpiration process.
Condensation: The water vapor condenses and forms clouds.
Precipitation: The water content in the clouds precipitates and falls on land. If it is at higher altitudes, the same precipitation of water in clouds may also fall as ice.
A very common and important source of water for all living being is groundwater. The water is stored under the ground; between layers of rocks. The upper limit of groundwater in place is called the water table.
Water table may vary at different places, it is usually higher in the plains and low in the plateaus.
Depleting water table
Human population has been growing rapidly, which creates increasing demand for water. This imbalance between increasing demand of water and shortage of water available leads to depletion of the water table and most of the places are facing acute shortage of water.
Forests are being cut to clear land for the growing population. Trees facilitate recharge of the water table as they make underground rocks pervious. Depleting forest cover has also curtailed the natural recharge of underground aquifers.
In India, some parts of the country get excess rainfall, while some get scanty rainfall. This uneven rainfall pattern also adds to the problem of water shortage.
Handling water shortage
Rain water harvesting:
Collection of rainwater for future use is called rainwater harvesting. India has been practicing rainwater harvesting for a long period; especially in rain deficient areas. For example; tankas and bawris had been in use in the northwestern part of India; especially in Rajasthan. A tanka is an underground tank to collect rainwater.
Rainwater harvesting can also be done in modern homes. The runoff rainwater from the rooftop should be collected in an underground reservoir. Such reservoirs are usually filled with sand and gravel to filter out impurities from water. The water can either be used directly or can be channelized to recharge the underground water.
Drip irrigation is a method through which maximum number of plants can be irrigated with minimum use of water. Water is saved immensely because drip irrigation can be done by laying pipelines throughout the rows of plants, Pipes are pierced at strategic points to release water only in droplets.
Steps one can take to conserve water:
- Water left after washing or bathing can be recycled for gardening.
- Immediately repair any leaking tap in the household.
- Close the taps while brushing your teeth.
- Avoid using a shower and use a bucketful of water instead.
The effects of water shortages
The effects of water scarcity can be grouped into these four broad areas— Health, Hunger, Education and Poverty. Lets touch upon the two prominent critical issues of health and hunger.
In many developing countries, people are forced to drink low quality water from flowing streams, many of which are contaminated. There are many water-borne diseases that people die off. Less water also means sewage does not flow and mosquitoes are other insects breed on still (stagnant) dirty water. The result is deadly malaria and other infections.
Lack of water or quality water causes huge sanitation issues. Clinics, local restaurants, public places of convenience and many other places are forced to use very little water for cleaning. This compromises the health of the staff and people who use the facilities.
It takes a lot of water to grow food and care for animals. Experts say that globally we use 70% of our water sources for agriculture and irrigation and only 10% on domestic uses.
Less water means farming and other crops that need water to grow have lower yield. It means farm animals will die and others will not do well without water. The result is constant hunger and thirst and a low quality of life.