Bharathappuzha, also known as the River Nila, is a river in India in the state of Kerala. With a length of 209 km, it is the second-longest river in Kerala, after the Periyar River. The word “Nila” indicates the culture more than just a river. Nila has groomed the culture and life of south Malabar part of Kerala. We see the name “Peraar” indicating the same river in ancient scripts and documents.

The headwaters of the main tributary of Bharathappuzha originates in the Anaimalai Hills in the Western Ghats, and flows westward through Palakkad Gap, across Palakkad, Thrissur and Malappuram districts of Kerala, with many tributaries joining it, including the Tirur River. For the first 40 km or so, the Bharathappuzha follows an almost northerly course till Pollachi near Coimbatore. At Parli, the Kannadipuzha and Kalpathippuza merge and flow as Bharathappuzha, following a westerly course until it empties into the Lakshadweep Sea at Ponnani. At Thiruvilwamala, Gayathripuzha merges with the river. The Thootha River merges with the Nila at Pallippuram. As the Thootha River is rich in water, after its merger, the Nila becomes thicker in flow.

The river is not navigable along most of its course except the small stretch where it joins the sea. With a watershed of 6,186 km², the Bharathapuzha basin is the largest among all the river basins in Kerala. A little more than two-thirds of this area (4400 km²) is within Kerala and the remaining area (1786 km²) is in Tamil Nadu. Though Bharathapuzha has a large basin, the water flow is relatively less compared to other long rivers in Kerala because a large portion of the basin is located in the comparatively drier regions (Tamil Nadu and Palakkad Gap). The construction of a number of dams after independence has also reduced the river flow. In fact in the summer months, there is almost no flow in most parts of the river. The river is the “Nile” of Kerala and has the name Nila also. The Bharathappuzha is the lifeline of many cities and villages.