SSC Stenographer 2026 PYQ — Question 27

Solution: The correct answer is Physiographic evolution and rainfall patterns.
Explanation:
☛ India's drainage system is primarily an outcome of the evolutionary process of the physiographic units and the nature and characteristics of precipitation (rainfall patterns).
☛ The geological history, including the uplift of the Himalayas, tilting of the Peninsular block, and subsidence of the trough between them, shaped the river courses.
☛ Rainfall patterns determine the volume of water and flow regime of rivers, categorizing them into perennial (snow and rain-fed Himalayan rivers) and seasonal (monsoon-fed Peninsular rivers).
☛ India's drainage systems are broadly divided into two major groups based on relief: the Himalayan Drainage and the Peninsular Drainage.
Extra Exam-Relevant Facts:
☛ Antecedent Drainage: Rivers like the Indus, Satluj, and Brahmaputra existed prior to the uplift of the Himalayas and cut deep gorges as the mountains rose.
☛ Water Divide: Major water divides like the Ambala-Delhi ridge separate the Indus and the Ganga drainage systems.
☛ Discharge of Water: Nearly 77% of the drainage area drained by the Ganga, Brahmaputra, Mahanadi, and Godavari flows towards the Bay of Bengal, while 23% drains into the Arabian Sea.
☛ Peninsular Tilt: A slight tilting of the Peninsular block from northwest to southeast direction gave the orientation to the majority of rivers flowing towards the Bay of Bengal.
Important One-Liners for Upcoming Exams:
☛ Which river divides the Peninsular plateau into the Central Highlands and Deccan Plateau? → Narmada River
☛ Which major Indian river flows through a rift valley between Vindhya and Satpura ranges? → Narmada River
☛ What drainage pattern resembles the branches of a tree? → Dendritic pattern
☛ Which river forms the world's largest riverine island, Majuli? → Brahmaputra River
☛ Which ridge acts as a water divide between the Indus and the Ganga river systems? → Delhi-Ambala ridge