Meandering Arroyos of the Dry Southwest

Abstract

HE recently cut arroyos of the Colorado Plateau and adjacent parts of the dry Southwest owe their prominence in scientific literature largely to the enlightening account of them by Kirk Bryan published in I925.1 The decade that has passed since the appearance of Bryan's paper has not seen the accumulation of new data that its author hoped to evoke. During this period, however, opinion seems to have crystallized that overgrazing, rather than one of the other agents cited by Bryan, has caused excavation of the arroyos. A recent paper by Reed W. Bailey2 may perhaps be taken as registering both the identification of overgrazing as the agent that has released the potentially destructive powers of runoff in the Southwest and the focusing of conservationist interest on its consequences. Aside from the well founded claim that these always striking and frequently appalling evidences of misuse of land in a dry climate must have on conservationist interest, they exemplify in a considerably simplified form-as compared with the channels of permanent streams in humid climates-the action of running water in sculpturing the land surface. It is from this latter viewpoint that they are brought under scrutiny in this article.