This temple is located right inside the Kallanai or Grand Anaicut dam across Kaveri in TamilNadu. It was supposed to be built by an English Captain J.L.Calddell in 1804.
The incident goes like this. The dam was undergoing repairs under Captain J.L.Calddell. The 19th vent could not be repaired how much ever they tried. The engineer had a dream in which Sri Anjaneya asked him to build a temple for him near the 19th vent and that he would protect it. The engineer ignored it and in a few days a group of monkeys attacked him. Then the same dream came for the Mason who reported it to the engineer.When they dug the spot, they recovered an idol of Sri Hanuman which can be seen in the temple now.
There is a stone, in one corner of the temple as a record of this fact to with a note “Repaired this colling LHA & Erected the 26s upright stones by Cap. J.L.Calddel AD 1804”. Below this there is a note in Tamil stating that the stone is erected as per the orders of the Government.
Hanuman Temple inside a Dam - Kallanai TN
It is more than two hundred years that Lord Sri Hanuman is protecting this two thousand years old bridge and the dam.Every year before the water is released for cultivation of paddy to the delta, poojas are conducted in this temple. Every season before the water is released for cultivation the paddy seeds are first offered to the Lord then to the river and then the water for irrigation is released from all sluices. Farmers, Engineers and Ministers used to participate in this pooja ceremony.