Periyar River

Periyar River, river in southern Keralam, southwestern India. Periyar, meaning “big river” in Malayalam and Tamil, is also the name given to a lake in the river’s course. The river, 152 miles (245 km) long, rises in the Sivagiri Hills of the Western Ghats range near the border with Tamil Nadu and flows north a short distance to Periyar Lake. It is the longest river in Keralam and is the second largest river basin of Keralam with a catchment area of 2,084 square miles (5,398 square km). Of this, 2,040 square miles (5,284 square km) lies in Keralam, and 44 square miles (114 square km) is in Tamil Nadu. The lake, 12 square miles (31 square km) in area, is an artificial reservoir created by damming the river. It lies at an elevation of about 2,800 feet (850 meters), is ringed by mountain peaks, and is surrounded by a wildlife sanctuary. A tunnel carries water from the lake eastward through the mountains to the Vaigai River in Tamil Nadu, where it is used for irrigation.

Path

From the lake the Periyar River continues to flow generally north to where it is impounded by an arch dam at Idukki that forms another large reservoir and is a major source of hydroelectric power for Keralam. The river continues northwest, descending out of the mountains and onto the coastal plain. It further flows into the Vembanad Lake before emptying into the Arabian Sea about 15 miles (24 km) north of Kochi. Several other dams have been built across the river since the late 20th century.

Tributaries

The Periyar River has several tributaries, including Mullayar, Idamalayar, Muthirapuzha, Cheruthoni, Kattapanayar, and Perinjankutti.

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Significance

The Periyar River is known as the “lifeline of Keralam” because it is an important source of irrigation and power generation. It is one of the few perennial rivers of the region and is a crucial source of drinking water. About 25 percent of Keralam’s industries are located along its banks. The river also supports a rich and unique biodiversity, particularly in the Periyar Tiger Reserve.

The river basin region has about 50 large and medium industries and about 2,500 small-scale industries. Some of the major industries are fertilizers, pesticides, chemicals, petroleum refining, and heavy-metal processing. Industrial pollution is a major concern, as pollutants such as pesticides, hydrocarbons, and untreated waste water are severely degrading water quality.

Periyar Tiger Reserve

The Periyar Tiger Reserve has been a protected area since 1934, when it was established as the Nellikampetty Game Sanctuary. The area was extended and renamed the Periyar Wildlife Sanctuary in 1950. It was given the status of a tiger reserve in 1978, and its core area was declared a national park in 1982.

The Periyar River, which originates deep in the reserve, sustains the land’s ecology and biodiversity. The tiger reserve is home to more than 50 percent of Keralam’s angiosperm species. It is also estimated to have 62 species of mammals, 323 species of birds, 38 species of fish, and 44 species of reptiles. Significant species include the Nilgiri tahr, Nilgiri langur, great hornbill, lion-tailed macaque, Malabar flying frog, gaur, and leopard. It is also a significant elephant and tiger habitat. The reserve is estimated to have about 40 tigers.

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