Paula Bañados, 19, along with 30,000 other protestors marched through the capital on a Friday, shouting, “Patagonia without dams!”

Ever since a government environmental commission approved the $3.2 billion HidroAysén dam complex in a popular region of Patagonia, with sites of breathtaking glaciers and lakes that attract thousands of tourists every year, protestors have organized large protests in several Chilean countries, in what became a national movement throughout the country.

In the case of Ms. Bañados, by the time she reached Chile’s presidential palace, people had begun to throw stones and pieces of wood at armored police vehicles. The police responded by firing water cannons into the crowd, driving them back.

This protest movement has caused 28 injured police officers and more than $100,000 in damage to public property and has rattled the government of President Sebastián Piñera, causing his approval rating to fall from 41% in March to 36% in April.