Drainage describes the river system of an area. The area drained by a single river system is called a drainage basin. And if any elevated area like a mountain or an upland separates two drainage basins, then it is known as water divide.
The drainage patterns depend on the slope of land, underlying rock structure and climatic conditions of the area. Some of the drainage patterns are:
- It develops where the river channel follows the slope of the terrain.
- The tributaries with the main stream resemble the branches of a tree.
- Eg: Krishna
- In this pattern, the tributaries are joined to the river at approximately right angles.
- It develops where hard and soft rocks exist parallelly.
- Eg: Siene
- It develops on a strongly jointed rocky terrain.
- Eg: Streams found in Vidhyan Mountains
- It develops when streams flow in different directions from a central peak or dome like structure.
- Eg: Narmada
The Indian rivers are divided into two major groups: Himalayan & Peninsular.
- They are perennial.
- They receive water from rain as well as from melted snow.
- They cut through mountains making gorges.
- Their courses are long.
- They perform intense erosional activity in their upper courses.
- They form meanders, ox bow lakes, and other depositional features in the middle and lower courses.
- They have well-developed delta.
- They are seasonal.
- They have shorter and shallower courses.
- They are dependent on rainfall.
- Most of them originate in Western Ghats and flow towards Bay of Bengal.