Thenmala Parappar Dam, the main dam of Thenmala which is the heart of Kallada Irrigation Project, the oldest irrigation project of Kerala. Parappar dam is having the longest dam reservoir among the dams of Kerala. Eventhough the dam hydel project is focussed on Irrigation process named as Kallada Irrigation Project electricity is also generated here. So its a hydro electric dam cum irrigation project. The dam reservoir spreads through the shenthurini wildlife sanctury in the valleys of western ghat mountain ranges. Parappar dam is built across Kallada river which is nourished with its main three river tributaries, Shentharuni, Kulathupuzha and Kalthuruthi puzha. The dam reservoir lake spreading through the valleys of western ghat mountains. The water appears dead still and calm.