1. Water and its usage
Water is an essential resources of the planet. Its usage should also be looked upon carefully.
Water is essential to life and is ubiquitous, found even on asteroids and other planets. Water is a tiny, fundamental molecule with a chemical formula of H2O consisting of two hydrogen atoms and one oxygen atom. It covers nearly three fourths of the earth surface but the distribution of water on the earth's surface is extremely uneven. Only 3% of water on the surface accounts for freshwater while the remaining 97% is salt water and resides in the ocean.
The different types of water resources are as follows:
* Groundwater
It is the water which has percolated the cracks and spaces in soil and land[1]. The water from groundwater is used for drinking and irrigation purposes. They are commonly called aquifers which are made up of gravel, sand, sandstone or fractured rock.
Groundwater can be replenished or recharged by rain, running water or snow melt by seeping into the soil. However, the natural replenishment rate should be higher than the consumption rate.
* Surface water
It is the freshwater in lakes, rivers, streams and reservoirs. Surface water is used for Agriculture, Industry, Transportation, Livestock. As it is present above the surface, it is easily accessible to humans and other living creatures on the planet. This makes it vulnerable to pollution and contamination due to human activities.
* Salt water
This is the most abundant water resource available on the planet accounting up to 97% of total water on the planet. The salt water can be found in oceans and seas and contains dissolved salts of Sodium, Chloride, Magnesium etc. The salinity of the salt water is 3.5% (35g of salt per 1 liter of water). This makes it unfit for drinking purposes[2].
Water is one of the most vital sources for all living organisms. We need water for various purposes such as agricultural, industrial, residential and commercial (Figure below). Although water is a renewable resource, scarcity of quality usable water is still a big issue in many parts of the world. Water scarcity is caused due to increased population, over extraction of the available water resource for agriculture and other commercial purposes and pollution of the accessible water resources. Therefore, efficient use of water is of utmost importance. The issue of water scarcity is discussed in the subsequent section.
