Since its founding in 1996, Carl Manzano has been the director of the Donau-Auen National Park. During his time in office, he made a major contribution to the conservation of the Danube region, above all to give the river back its freedom, to prevent it from silting up and to achieve sustainable bank design. In 2019 he was honored with the Golden Medal of Honor of the Republic Austria. Manzano was also co-initiator and organizer of the antinuclear power movement in Austria, which led to the referendum against the Zwentendorf nuclear power plant.