India is endowed with a vast network of surface water resources, primarily comprising rivers, lakes, and reservoirs, which play a crucial role in irrigation, hydropower generation, industrial use, and domestic consumption. The distribution of these surface water resources is largely determined by the country’s physiography, rainfall patterns, and climatic conditions, leading to significant regional variations. The major river systems of India can be broadly classified into Himalayan rivers and Peninsular rivers. Himalayan rivers, often referred to as perennial rivers, originate from the snow-capped mountains of the Himalayas. They include the Ganga, Brahmaputra, Yamuna, and their numerous tributaries. These rivers receive water from both rainfall and melting snow, making them active throughout the year. The Ganga basin is the largest in India, covering a large portion of northern India and parts of neighboring countries. It supports extensive agricultural activities and sustains dense populations. The Brahmaputra in the northeast carries one of the highest sediment loads and exhibits massive seasonal flooding due to heavy monsoon rainfall.