Kerala Tourism Photos – Thenmala Dam dams kerala kerala dams kerala photos kollam natural thenmala tourism by Kerala Photos - February 22, 2013May 19, 2016 Thenmala Dam – Kollam, Kerala Photos Thenmala is in Kollam district and this Thenmala dam was built across the Kallada river. Thenmala dam is the second largest irrigation project in Kerala. Thenmala dam is said to be the longest reservoir in Kerala and its water is used for generating power. With combined effort of Kallada irrigation and tree crop development project, the dam was built in 1961. Rate this post