Hydrosphere is one of the most crucial sphere of the earth for the sustainability of life. Earth’s Hydrosphere consists of 71% of the area out of which only 3% is present as freshwater. The rest spheres of the water is present in oceans and is unfit for human use or is stored as glaciers or ice sheets and the rest of the water as groundwater.

Many of the important energy and matter exchanges take place in this sphere of earth. The water cycle is an example of such matter exchange in which water undergoes recycling and reusing.

The water cycle helps in keeping a healthy ecosystem around us. The growth of most of the crops and plants is dependent on the waterfall. Indirectly many organisms depend on these crops for their survival.

Hydro energy is used for electricity generation. A large number of dams are built on rivers for irrigation, water storage, flood control, etc.