The wide, broad plains or uneven tracts with gradual slopes between the mountains are called valleys. They are found in the mountains all over the world. Srinagar is one of the beautiful valleys in our country. Do you know how valleys are formed?
Most of the valleys were formed by rivers. When streams originate on hill top, their water flows down the side of the hill. Because of the steepness of the slope, the river flows very fast and the force of water eats into the hillsides, forming a narrow V-shaped bed. With the passage of time, it becomes U-shaped when the water from other sides joins it and its breadth goes on increasing. Eventually the banks of the river become flat and the floor of the river widens. The area almost becomes like a plain. This is how a valley is formed. It takes thousands of years for its formation.
Some valleys have been formed by glaciers. Glaciers are slow moving rivers of ice. The ice grinds deeply into the ground and at the same time smoothens out any ridges in its path. The glacier picks up all the rocks and other projections that come in its path, breaks them up and redeposits them smoothly over the ground. This makes the ground smooth and a U-shaped valley comes into existence.
Sometimes the river changes its direction and thus the river bed becomes dry. The valley formed in this manner is called a dry valley.
Sometimes when land sinks between two fractures in the earth’s crust, a valley is formed. These valleys are called ‘rift valleys’. The most famous valley of this type is the Great Rift Valley, which extends to more than 5000 km from Syria to East Africa. Narmada, a famous river of India, also flows through a rift valley.
All the ancient civilizations started in the valleys only.