Drainage Test - 15

• An area drained by a river and its tributaries is known as a drainage basin. 
  
• Radial drainage patterns form when rivers originate from a hill and flow in all directions. For example, the rivers originating from the Amarkantak.

Rajsamand Lake (also known as Rajsamudra Lake) is a lake near the town of Rajsamand in the Indian state of Rajasthan. Built in the 17th century, it is approximately 1.75 miles (2.82 km) wide, 4 miles (6.4 km) long and 60 feet (18 m) deep. It was built across the Gomati, Kelwa, and Tali rivers, with a catchment area of approximately 196 sq mi (510 km2).

Though there may rivers in India, the most important of them is the Ganga River. The length of Ganga river is 2,525 km. It rises in western Himalayas in Uttarakhand, flows up to Bangladesh and then empties into Bay of Bengal.

• The Koshi was also called Kausika in Rigveda, Nepal and Bihar in northern India. It is a major tributary of the Ganges. One major tributary of the Koshi is the Arun, much of whose course is in Tibet. This river is mentioned in the epic 'Mahabharata' as Kausiki.
  

Chilka lake and and Pulicat lake are best example of lagoon which is also found in this region. The Orissan plainis also known as the Utkal Plain. Theplain between the Godavari and the Mahanadi is known as the Northern Circar whereas the eastern coast of Tamil Nadu is called the CoromandelCoast.

The holy city of Varanasi is situated on the banks of Ganga river.

River regulation includes construction of irrigation canals, ditches, drainage tunnels and damns. Though they have an immense utilization for the well-being of people, it has its own defects as it affects the natural flow of water. There will be changes in physical and chemical conditions, resulting in changes in animal and plant life of the river.