Shinumo Wash actually begins its journey as several shallow dry washes which all begin between Bitter Springs, AZ and Cedar Ridge community on Navajo lands on the east side of the Marble Canyon/Grand Canyon walls. At least three large dry washes combine just east of Shinumo Altar to form the larger wash. There, they become a deeper canyon with Vee shaped walls which continues to meander for about four miles. Then, the canyon emerges through the low ridge of Eminence Break and becomes a shallow wash once again for another two miles.
Finally, Shinumo Wash begins to earnestly cut down into, and through, the sedimentary layers of the walls of Marble Canyon. After just another four miles the wash has gone from being just a few feet deep to more than 2,000’ deep at its confluence with the Colorado River.
GCPano.org