Ans: Rain as a natural source of water:
Rain is a natural source of water. Water from rainfall on mountains and
melting glaciers gathers in rivulets and keeps them flowing throughout the
year. Arid areas and their production is more dependent on rain than canal
irrigated areas. Tarbela and Mangla are important irrigational dams in which
not only lakhs of acres feet water is collected but also cheap hydro electricity
is produced. Besides these two reserves, Chashma Barrage has 5 lakh acre
feet reserves of water as well.