Posts by Barbara Fraser

Learning from a Flood-Alarm System’s Fate

Posted by on May 31, 2017 in Adaptation, All Posts, Featured Posts, News, Policy and Economics | 0 comments

Learning from a Flood-Alarm System’s Fate

Spread the News:ShareA longer version of this post appeared in the April 2017 issue of EcoAmericas. When a flood from a mountain lake threatened to swamp the town of Carhuaz in the Peruvian Andes early one morning in April 2010, Víctor Rodríguez was the only person who knew. From his hut on a plain below the mountain, he heard the jet-like rumble as a block of ice calved off a glacier and crashed into the lake. The force of the fall produced a wave that swept over the earthen dike around the water body, called Lake 513, and cascaded down the steep slope. Rodríguez watched as the water swirled across the plain, swamping the catchment for the municipal water system, where he worked as caretaker. Picking up speed as it funneled into the Chucchún River, the torrent of water carrying mud and boulders swept away crops, livestock and some buildings. But it stopped just short of the town of about 12,000 people beside the Santa River, at the foot of Peru’s Cordillera Blanca. The Destruction of an Early-Warning System With climate change increasing the threat of such hazards, the Swiss government’s development agency, a Peruvian nonprofit, and a Swiss university teamed up to develop a high-tech early-warning system. By the end of 2013, lakeside sensors and cameras were in place above Carhuaz, with relay antennae that could transmit information quickly to a command center in the municipal offices. Once its kinks were worked out, the organizers of the project hoped the system could serve as a model for other towns that lie below glacial lakes. Then disaster struck again, this time in the form of a drought. Not only was rain scarce, but an unseasonable frost damaged crops. Rumors spread among residents of the farming communities around Carhuaz that the monitoring equipment at Lake 513 was preventing clouds from forming. Early one morning last November, several hundred people from the largely indigenous communities, where traditional Andean beliefs still hold sway, trekked up to the lake and tore down the system. Within a week, it rained. The events raise questions about how to ensure that in areas where rural residents distrust technology, systems can be created to reliably warn those in the path of Carhuaz-style deluges, known as glacial lake outburst floods, or GLOFs. It also highlights tensions between growing urban areas and their rural neighbors— tensions that could deepen as dense development encroaches on agricultural land and city dwellers demand a larger share of water from threatened sources. The destruction of the Carhuaz early-warning equipment came as a shock to the system’s developers, but in hindsight, signs of discontent had been building. During workshops in 2012, residents said they felt unprotected against outburst floods like the one in 2010, says Karen Price Ríos of CARE Peru, a nonprofit development organization that has been active in the area for several years. Price worked with local communities on the three-year early warning project, which was funded by the Swiss aid agency COSUDE and supported by researchers from the University of Zurich. The researchers drew up a risk map, showing the areas in varying degrees of danger from a mudslide like that of 2010, and devised evacuation routes, marking them with signs. The centerpiece of the project was the early-warning system on Mount Hualcán. If a block of ice broke from the glacier and crashed into Lake 513, it would trigger sensors that would turn on cameras and send an alert to local officials. They could then check the images from the cameras to verify the flood and sound an alarm. The...

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