Torrentera Hazard Mapping

The city of Arequipa is positioned at the foot of two mountains with elevations over 19,000 feet. During the rainy season, December to March, intense rain events cause torrential flows through ephemeral stream channels that lead into the city, known locally as torrenteras. In many areas, development has overcome the floodplain of these torrenteras. As a result, short, intense storms cause flash floods and associated hazards. In many areas, streamflow causes overbank flow that flood many buildings along torrentera banks. Steep channels and high flows cause high velocities capable of sweeping away humans, vehicles, and other objects. Steep banks close to these channels may also be suseptible to failure, particularly where stream power is high. The maps below show examples of how inundation, velocity, and slope instability hazards can impact the torrenteras and surrounding areas within the city of Arequipa.