Question

When does a drought occur?

Answer 1

Hint:
Water is the most important natural resource which is very vital for the living world. Though the earth’s 70% of the earth’s area is occupied by water but only 2.5% of the freshwater resources are available. The maximum volume of water is ocean water.


Complete answer:
Step 1
In the earlier days, water was thought to be an element, till in 1781 Henry Cavendish showed that water can be prepared by igniting a mixture of two volumes of hydrogen and one volume of oxygen.
Step 2
There is surface water and groundwater available in the earth. The water which is located on the top of the Earth’s surface like a river, ponds, lakes are known as surface water. It is also known as blue water. Groundwater is the water that exists underground which flows naturally out of the rock materials.
Step 3
The water balance is maintained on the earth’s surface by a natural phenomenon known as the water cycle. In the water cycle, first, the surface water gets evaporated due to the heat by the sun rays. The evaporated water vapor rises up and gets condensed to form water droplets and forms the cloud. When the cloud gets heavier precipitation in the form of rain, snow, hail take place, and again this water seeps into the surface water and the groundwater thereby maintaining the water level.
Step 4
The major use of rainwater is in agriculture. The soil gets enough water, where the crops can grow properly. Water is required for the proper growth of the crops. When there is a proper rainfall the atmospheric temperature remains soothing.
Step 5
Sometimes there are situations when there is little or no rainfall for a longer period of time maybe for a year or two. This condition is known as drought. During this period both surface and groundwater are scarce. The lakes and the ponds dry up, thereby the aquatic plants and animals die. The soil gets extremely dried up and is left with cracks where the plantation is not possible. So, a famine takes place due to this condition. The animals which drink water from the nearby lakes and ponds die out of thirst.

Note:
Drought is a natural calamity which is an emergency situation. Sometimes it takes more than ten to twelve years to revive back after a drought period. It leads to a severe climatic change, change in the course of the rivers or total environmental change. Afforestation, rainwater harvesting are some of the important measures that can be taken to fight this natural calamity.