Residents in Chile’s capital Santiago are pleased to see the Mapocho River recovering. Around 1,000 people ran along its banks one Sunday afternoon, an event impossible a few years earlier because of severe pollution. For decades nearly all of the city’s waste flowed into the 110-kilometer waterway, turning it into an open sewer whose odor made people cover their noses. Santiago’s nearly 10 million inhabitants now feel relief after a new sanitation system restored the river. A 58-year-old runner said it was satisfying to restore something once almost gone but now healthy. Twelve kilometers upstream at the river’s origin, an agronomist from the Mapocho Vivo Foundation praised the nutrient-rich water after a 12-year cleanup finished in 2010. The project, recognized by the United Nations at COP24, built a 28-kilometer tunnel that sends wastewater to treatment plants. Cleaned water returns to the river and irrigates crops, removing risks of typhoid and hepatitis that once came from using untreated water. All waste now produces gas to run the plant, while sludge becomes farm fertilizer. Roughly 80 native and introduced species now thrive in and around the river. An endemic catfish only a few centimeters long has returned, showing the water supports life again. The river was named an urban wetland in January, yet litter still appears on some banks. It crosses 16 municipalities, and divided local management complicates protection. The recovery forms part of wider changes in Santiago that include a 42-kilometer cycle path and new riverside parks.
