The River Periyar has great relevance and the contributions it makes to the landscape, ecology, flora and fauna all along its glorious course is immeasurable. Periyar in Malayalam means ‘big river’. With a length of 244 kms., it is the longest river and has the largest discharge potential among the rivers in Kerala. It certainly is the ‘Lifeline of Kerala’, as it provides drinking water for almost all the major towns in Kerala, along its path. It also contributes significantly to the economy of Kerala, because it generates the bulk of the state’s electrical power output at the Idukki hydro-electric plant. Throughout its course, Periyar supplies its precious water resource generously for irrigation and domestic use besides supporting a rich fishery, forest vegetation and wildlife.
At the very source of the Periyar River, there is a stretch of about 350 km2 of the most inaccessible and least disturbed wet evergreen forests of the Western Ghats. This area is also part of the highly protected Periyar Tiger Reserve. About 1,966 species of angiosperms out of the total estimated 3,800 species in Kerala is found within this reserve. The reserve also contains an estimated 323 species of birds, 38 species of fish and 44 species of reptiles. The reserve supports about 2000 elephants as well.