The major tributaries of the river Krishna are the Koyna, Tungabhadra, and Bhima rivers. Let's understand why these rivers are considered the major tributaries of the Krishna river.

- Koyna River: The Koyna river is a tributary of the Krishna river, flowing through the state of Maharashtra. It originates in the Sahyadri range near Mahabaleshwar and joins the Krishna river near Karad. The Koyna river is known for the Koyna Dam, one of the largest dams in Maharashtra. The dam provides hydroelectric power and irrigation water to the region. The Koyna river contributes a significant amount of water to the Krishna river, making it an important tributary.

- Tungabhadra River: The Tungabhadra river is another major tributary of the Krishna river, flowing through the states of Karnataka and Andhra Pradesh. It originates in the Western Ghats near the town of Chikmagalur and joins the Krishna river near the town of Alampur. The Tungabhadra river is known for its historical importance, as it flows through the ancient Vijayanagara Empire, which was a prominent South Indian kingdom. The Tungabhadra Dam, built across the river, provides irrigation water and hydroelectric power to the region. The Tungabhadra river adds a significant amount of water to the Krishna river, making it a crucial tributary.

- Bhima River: The Bhima river is another major tributary of the Krishna river, flowing through the states of Maharashtra and Karnataka. It originates in the Bhimashankar hills in Maharashtra and joins the Krishna river near the town of Raichur. The Bhima river is known for its agricultural importance, as it provides irrigation water to the fertile regions along its course. The Ujjani Dam, built across the Bhima river, is one of the largest reservoirs in Maharashtra and supplies water for irrigation and drinking purposes. The Bhima river contributes a substantial amount of water to the Krishna river, making it a significant tributary.

In summary, the Koyna, Tungabhadra, and Bhima rivers are considered the major tributaries of the Krishna river because they provide a significant amount of water to the main river. These tributaries play a crucial role in the overall water availability, irrigation, and power generation in the regions they pass through.