Thonnakkadavu Lake and Dam are part of the Parambikulam Aliyar irrigation Project. Built across the Thunakkadavu river, a tributary of the Parabikulam river, the reservoir is an attractive tourist destination. The unique beauty of the lake is well known among travelers. Though it is small compared to other dams in the state, the surrounding green hills, thick forest, and wildlife make it a favorite destination for sightseeing enthusiasts. The top of the dam is the perfect spot to enjoy these sights. This makes it one of the best tourist spots in Parambikulam.