Koyna Dam is an inland excursion from Chiplun into the Western Ghats, better suited to travellers with their own vehicle than to a casual town walk. The road climbs away from the Konkan humidity into forested hill country.
The dam itself is more engineering site than tourist showpiece, but the surrounding Koyna landscape is the reward. Combine it with viewpoints or other Ghats stops rather than making a rushed out-and-back only for the structure.