Which major multipurpose hydroelectric project constructed across the Periyar River features the country's first arch dam?

💡 Solution & Explanation

The Idukki Dam is a double-curvature parabolic thin arch dam constructed across the Periyar River between the Kuravan and Kurathi hills, serving as a landmark engineering feat in hydroelectric generation. Banasura Sagar is an earth dam located on the Karamanathodu River, whereas Mullaperiyar is a masonry gravity dam situated upstream. Arch dams require narrow rocky gorges and possess high structural strength against water pressure.