Arabian Sea and Bay of Bengal drainage
Topic: Drainage System of India: Rivers, Basins and Patterns · NCERT: Class 11, Ch 3 "Drainage System"
Meaning
India's rivers can be grouped by the sea they finally flow into. About 77 per cent of India's drainage area sends its water to the Bay of Bengal. About 23 per cent sends it to the Arabian Sea. A line of high ground forms the divide (the dividing line between the two groups). It runs along the Delhi ridge, the Aravallis and the Sahyadri (Western Ghats). The share is so uneven because most of the Peninsula tilts gently towards the east, so most big rivers flow east.
Example
The Ganga, Brahmaputra, Mahanadi, Godavari, Krishna and Kaveri all reach the Bay of Bengal. The Indus, Narmada, Tapi, Mahi and Periyar flow into the Arabian Sea. The Narmada and Tapi flow west along trough faults (long sunken strips of land between cracks in the rock).
Don't confuse with
- Himalayan and Peninsular drainage: this grouping is by where a river starts, not where it ends. The Indus is Himalayan and drains to the Arabian Sea. The Godavari is Peninsular and drains to the Bay of Bengal.