Ch. 23] CORRECTIVE TREATMENT FOR GULLIES 425 



of such gullies would cause waves of deposition to migrate slowly up- 

 valley, thus leaving what appeared to be a continuous fill of the same 

 age but which in reality would vary greatly in age in different reaches 

 of the valley. Development of terraces would naturally be associated 

 with this process. Likewise a subsequent gully, cut along the line of 

 the buried discontinuous channel, would expose filled sections duplicat- 

 ing those found at present. Although this interpretation is logical in 

 some respects, to accept it would simply mean admitting that erosion 

 in past periods differed from that of the present only in extent. Under 

 these conditions it hardly seems consistent to attribute one to natural 

 causes, the other to overgrazing. Antevs has also pointed out this 

 inconsistency (Antevs, 1948, p. 12). 



From this brief mention of the investigations directed toward ap- 

 praisal of the effect of climatic fluctuations on erosion, it should be 

 apparent that much research is still needed before its full importance, 

 as applicable to the erosion problem of the West, can be determined. 



CORRECTIVE TREATMENT FOR GULLIES 



No generally successful method of gully treatments which has proved 

 capable of preventing both lateral and headward cutting has yet been 

 devised. Even the task of arresting headcuts, where the treatment 

 can be concentrated on a small area, has proved both difficult and ex- 

 pensive, and many efforts have ended in failure. The greater and 

 more complex problem of stopping bank cutting where miles of raw, 

 vertical walls composed of highly erodible alluvium are exposed is 

 still more difficult of solution, and the final task of reversing the present 

 phenomena to the extent of substituting aggradation for degradation 

 in these narrow channels will doubtless prove most difficult of all. 



To date, the program of treatment has followed two general lines: 

 (1) reduction of grazing use, and (2) installation of control structures 

 of various types. Unfortunately, in most instances, these were not 

 combined, so the full effect of the two acting in unison cannot be 

 evaluated. 



Naturally, if it is assumed that overgrazing is responsible for erosion, 

 the obvious treatment is reduction or complete exclusion of livestock 

 from eroding areas. As such action directly affects the livestock in- 

 dustry, it raises questions of a social and political nature which have 

 not yet been resolved. Livestock growers, although fully conscious 

 of the erosion menace, are generally not convinced that their herds 

 are completely responsible for it or that removal of them will effect a 

 cure, and such reduction as has been accomplished has generally been 



