426 peterson. PROBLEM OF GULLYING [Ch. 23 



with the idea of increasing forage rather than as a treatment for 

 erosion. 



Locally tracts have been fenced or otherwise protected to demon- 

 strate the advantages of reduced grazing on both increased forage pro- 

 duction and decreased erosion. The results vary widely, as indicated 

 by Fig. 4, which shows typical demonstration areas. In some localities 

 the recovery has been excellent; in others, insignificant. It is apparent 

 from this that availability of moisture, condition of the soils, and 

 other ecological factors may have as strong an influence on vegetative 

 recovery as utilization. 



Structural treatment was extensively used during the C.C.C. pro- 

 gram, which lasted from the early 1930's to 1942. These structures 

 were generally of simple design and, since the program was aimed at 

 work relief, a large part represented hand labor. Most of the early 

 treatment areas were confined to tributaries of the major channels 

 or to areas in which smaller gullies had developed, and only occasion- 

 ally was an effort made to treat or control the larger features. The 

 structures utilized were of wide variety and included water spreaders 

 of many different types, check dams, contour furrows and terraces, 

 diversion and training dikes, and small to moderately large storage 

 and silt-detention reservoirs (Fig. 6) . Essentially the basic aim of the 

 program was to induce vegetative recovery which would in turn furnish 

 greater opportunity for percolation and thus reduce floods to safe and 

 non-eroding rates. As there was no precedent for this type of treat- 

 ment, much of it can be considered strictly experimental in nature, and 

 failure in many instances to achieve the hoped-for results is not to be 

 considered a reflection either on the designers or on the idea of land 

 treatment. Future practices should benefit from these mistakes. 



Appraisal of the results of the treatment programs on both erosion 

 and revegetation presents, in general, a discouraging outlook. Detailed 

 examinations by personnel of the U. S. Geological Survey of seven 

 treated areas comprising a total of 5,600 acres located in the Upper 

 Gila River in Arizona and New Mexico show that, of the 1,094 in- 

 dividual structures, 375 or 30 percent have failed for various reasons, 

 the most prevalent being undercutting and piping in the foundations 

 and lack of maintenance. More significant than the failures, however, 

 which doubtless could be eliminated by a higher standard of construc- 

 tion and careful maintenance, is the lack of any discernible evidence 

 of soil stabilization or vegetative recovery in areas controlled by struc- 

 tures that have not failed. In all cases vegetative recovery has been 

 classed as unnoticeable or no different from adjacent untreated areas. 

 Moreover, the treatment has had little effect in preventing soil move- 



