- ∗ The suggestions of Dr. R. D. Heil, Department of Agronomy, Colorado State University, Dr. S. A. Schumm and Dr. R. S. Parker, Department of Geology, Colorado State University, and the members of the graduate seminar in geomorphology, Colorado State University, are gratefully acknowledged.
- 1 L. B. Leopold and J. P. Miller, Ephemeral Streams: Hydraulic Factors and Their Relation to the Drainage Net, Professional Paper 282A (Washington: U. S. Geological Survey, 1956).
- 2 Leopold and Miller, op. cit., footnote 1, p. 30, said that “the salient characteristic of a discontinuous gully is the relatively small gradient, or slope, of its bed. It is this flat slope—less steep than the floor of the original ungullied valley—that makes the gully discontinuous, for the bed profile must at some downstream point intersect the profile of the original valley floor. At that point the gully depth has diminished to zero.”
- 3 Data from the United States Department of Commerce, Environmental Sciences Administration, Climatological Data for Wyoming, Vol. 78 (1969).
- 4 J. Leighly, “Meandering Arroyos of the Dry Southwest,”Geographical Review, Vol. 26 (1936), pp. 270 82.
- 5 S. A. Schumm and R. F. HadleyArroyos and the Semiarid Cycle of Erosion,”Amercian Journal of Science, Vol. 255 (1957), pp. 161 74.
- 6 C. W. Thornthwaite, C. F. S. Sharpe, and E. F. Dosch, Climate and Accelerated Erosion in the Arid and Semiarid Southwest, With Special Reference to the Polacca Wash Drainage Basin, Arizona, Technical Bulletin 808 (Washington: U. S. Department of Agriculture, 1942).
- 7 Dr. D. V. Harris, personal communication.
- 8 The obvious importance of trampling by cattle in preventing revegetation of bare patches suggests an analogy with the “buffalo wallows” elsewhere on the Great Plains.
- 9 G. W. Brown, “Piping Erosion in Colorado,”Journal of Soil and Water Conservation, Vol. 17 (1962), pp. 220 22.
- 10 Leighly, op. cit., footnote 4.
- 11 A number of lakes in the area are due to deflation; D. V. Harris, “Geomorphology of Larimer County, Colorado,” in P. J. Katich and D. W. Bolvard, eds., Geology of the Northern Denver Basin and ént Uplifts, Rocky Mountain Association of Geologists (1963).
- 12 Some gullies have a “headcut” at their downstream ends. The gradient of the valley floor is so low that in some places water may actually flow upvalley to the nearest basin and cause erosion at its down-stream end.
- 13 M. G. Wolman, “Factors Influencing Erosion of a Cohesive River Bank,”American Journal of Science, Vol. 257 (1959), pp. 204 16.
- 14 W. S. Chepil, Soil Conditions That Influence Wind Erosion, Technical Bulletin 1185 (Washington: U. S. Department of Agriculture, 1958).
- 15 J. H. Stallings, Soil Conservation (Englewood Cliffs, N. J.: Prentice-Hall, 1957), p. 77.
- 16 W. S. Chepil, “Influence of Moisture on Erodibility of Soil by Wind,”Soil Science Society of America Proceedings, Vol. 20 (1956), pp. 288 92.
- 17 Leighly, op. cit., footnote 4; and Dr. R. D. Heil, personal communication.
- 18 Dr. R. D. Heil, personal communication.
Annals of the Association of American Geographers
Volume 62, 1972 - Issue 4