This is a brief description of a trip to Hogenakkal in Tamil Nadu, India in February 2008. These falls are certainly not well known outside India. In fact, we were the only non-Indians to be seen there on that day.
The same report is also available in

It was the dry season. As a result, the falls were mostly not strong. But despite the low water, one of the many falls formed by the river remained strong. On the positive side, it was possible to go on boat rides inside the gorge cut out by the river (800 Rupees per boat is a fair price; it fits up to 6 persons plus the boatsman).

It is also possible to swim in the river during the dry-season. In fact, many Indians can be seen at least taking a bath, as the river is supposed to have medicinal benefits. Nevertheless, I would not want to risk drinking any of its water.

Just after reaching the end of the gorge one can find a river bank with many stalls. Fish is caught inside the gorge. One can buy it fresh directly from fishermen within the gorge and have it prepared at one of the many kitchens on this river bank.