Figure 16.28

An alluvial fan. This satellite image shows an alluvial fan (outlined with dotted line) in the Zagros Mountains of southern Iran. Here, an ephemeral stream emerges from a canyon and spills out onto the fan only after rare rainfall events. When flowing, the stream occupies only a small portion of the fan at any one time. Through time, the stream migrates across the fan. The green crops seen here get their water from pumped groundwater, not surface streams.

(NASA image created by Jesse Allen, using data from NASA/GSFC/METI/ERSDAC/JAROS, and the U.S./Japan ASTER Science Team)