Deadman Wash

Though many watersheds are present along and proximal to the C. Hart Merriam Elevation Gradient, the most prominent is Deadman Wash. Deadman wash is an approximately 40 mile long drainage that traverses the north side of San Francisco Mountain in an east-west fashion, ranging in elevation from about 7,700 ft. (2348m) to about 4,200 ft. (1280m).

Deadman Wash is important for several reasons: 1) it roughly parallels the C. Hart Merriam Elevation Gradient and contains the same variation in vegetation resulting from the drastic change in elevation over a relatively short distance--as such, it provides relatively easy access to a natural transect through the elevation gradient; 2) it runs from the north side of San Francisco Mountain to the Great Basin Desert, potentially connecting waters of San Francisco Mountain with the Little Colorado River; and 3) it was likely an important travel route for early native cultures of the area, such as the Sinagua, and many petroglyphs are found along its walls--thus, it provides good insight into the lives of these ancient cultures.

Surface water and groundwater

Surface water is not known to flow in Deadman Wash, except during torrential summer rainstorms or during spring snowmelt following a wet winter. Thus, erosion likely occurs episodically. Springs from atop San Francisco Mountain may have contributed to some flow within the drainage in the past, but most of these high elevation springs have been tapped by the City of Flagstaff and no longer flow freely themselves. Therefore, Deadman Wash probably does not contribute significantly to the flow of the Little Colorado River, except perhaps during spring and summer.

Either way, surface water does not remain for long--it infiltrates the loosely consolidated alluvium of the channel rather quickly. The lithologies (rock types) found within the drainage are either basalt, limestone, or sandstone. The limestone and sandstone units were deposited several million years ago in an inland sea. The basalts later flowed over the older rocks that had been uplifted by plate tectonic processes.

Younger alluvium within the drainage can sit directly on top of relatively non-porous basalt or silty layers, resulting in the formation of local, perched aquifers. Water within the larger, regional aquifer tends to flow either north to Grand Canyon or south to the Mogollon Rim and Verde Valley. Thus, neither groundwater nor surface water are significant in the Deadman Wash area. This fact has puzzled archaeologists attempting to learn how ancient cultures of the area might have eeked out a living.

The Deadman Wash area has not been thoroughly studied, probably for its lack of potentially large water sources. Nevertheless, there is no doubt a great deal of information to be learned from the area. Whether studying the vegetation changes along the elevation gradient or the petroglyphs and artifacts left by native cultures that migrated through the area, it is a natural laboratory for learning that itself raises many new and puzzling questions.