REASONS FOR THE SURVEY 3 



scarcely any profit from this industry, and the returns to the lumber- 

 men were also relatively small. If the cheap transportation which a 

 canal furnishes had been in existence earlier, much more conservative 

 logging operations could have been carried on ; much closer utilization 

 of material could have been made by mills situated along the route ; 

 much more profit could have been secured from this resource by both 

 operators and the people, and, moreover, the source could have been 

 managed for perpetuity, as a basis for manufacturing industries. As 

 it is, the principal local freight, that from the timber-lands, is almost 

 exhausted, and a large part of the usefulness of the canal has gone, at 

 least in so far as local development is concerned. Outside of the 

 water-power which it supplies, through traffic, which may follow upon 

 the completion of the two outlets, can alone justify its existence for the 

 present ; unless by careful planning and management a revival of the 

 industrial activity, to which, at one time, the lumberman gave rise, can 

 be seciired. 



Forest and Waterflow — Meanwhile, another important factor in 

 the problem, which is closely connected with the timber question, has 

 been entirely lost sight of, namely, the securing of adequate water 

 supplies for canal and power purposes by the conservation of a forest 

 cover on the watersheds. Indeed, this factor, the conservation of 

 water supplies, is one of paramount importance to the canal. What- 

 ever may be said regarding the influence of deforestation on climate, 

 an influence which, it must be admitted, is only imperfectly under- 

 stood, there can be no question as to the influence on waterflow which 

 a forest cover exercises. That such a cover prevents extremes of low- 

 water and high-water stages, and generally regulates and equalizes 

 waterflow, has been proved both by experience and experiment in all 

 parts of the world. 



The effect of this influence can be readily explained if it is assumed 

 to act under extreme conditions. Consider a watershed with bare, 

 rocky slopes. It is obvious that the water precipitation on it will run 

 off as fast as it falls ; that the water stages in the river will be as erratic 

 and fitful as the rainfall ; and that low-water and high-water stages 

 will alternate in conjunction with dry and wet periods. 



Now, consider the rock covered not only with soil and vegetation, 

 but also with a dense forest growth, and then compare this condition 

 of the watershed with the one previously mentioned. The rapid run- 

 off is prevented by percolation ; the surface drainage is largely changed 

 into subdrainage ; the river is to some extent fed by springs instead of 

 surface flow ; the time during which the waters reach the river is length- 

 ened ; and the flow becomes more even. Although in the case of un- 

 usual rains and precipitous slopes even the forest cover may not prevent 



