Soon enough, the number of cars driving up the valley had almost doubled, forcing the local authorities to add traffic police because of road jams and parking problems. Many day-trippers from Milan and elsewhere picnic along the river, leaving litter rather than filling local restaurants.

All of that publicity around the bridge has not brought any significant financial benefit to the valley, officials said, but it confirmed, instead, the need to focus on projects like Corippo’s hotel.

To profit from tourism, the area needs to make “every effort to transform day tourism into a stay of at least two or three days in our valley,” said Alan Matasci, the president of the Verzasca foundation in charge of the valley’s development.

Mr. Matasci forecast that Corippo’s hotel would bring overnight visitors without adding to the risk of mass tourism, a phenomenon also unlikely given the village’s size and geographic isolation: The narrow road that winds up to Corippo ends in a cul-de-sac on the church square.

“We can’t predict or control exactly how tourism develops,” Mr. Matasci said. “But we can say that without this hotel, there will probably be nobody living in Corippo in 15 years.”