The Equalizing Influence of Forests on the Flow 

 of Streams and Their Value as a Means of 

 Improving Navigation* 



By GEORGE F, SWAIN, LL.D,, Professor of Civil Engineering 

 in the Massachusetts Institute of Technology 



IT IS the opinion of probably the 

 great majority of engineers con- 

 versant with the subject, that for- 

 ests act as equalizers of the flow of 

 streams by diminishing, in general, the 

 frequency and violence of freshets, and 

 increasing the low-water flow, and by 

 preventing the erosion of the soil and 

 the consequent silting up of water- 

 courses. 



Based on these premises, it is believed 

 to be of much importance to the inter- 

 ests of navigation, as well as to other 

 interests, that the United States Gov- 

 ernment should establish forest re- 

 serves in the Southern Appalachian and 

 \Yhite Mountains, the object of such 

 reserves being: 



First, to aid in the protection of cer- 

 tain given watersheds. 



Second, to enable the Government to 

 give an object-lesson to private owners 

 in the vicinity as to what may be ac- 

 complished by proper forest manage- 

 ment, and to cooperate directly with 

 such private owners in encouraging 

 them to use the best methods. 



Third, to aid in preventing forest 

 fires and the consequent deterioration 

 of the soil and destruction of timber on 

 both Government and private lands. 



Fourth, to aid in and encourage re- 

 foresting, and, by this means, and by 

 proper management, to augment and 

 prolong the timber supply. 



In September, 1908, a paper, the title 

 of which has been quoted below, was 

 published in the Proceedings of the 

 American Society of Civil Engineers, 

 by Col. H. M. Chittenden, of the Corps 

 of Engineers, U. S. A., in which argu- 

 ments were advanced which in a meas- 

 ure seem to controvert the generally 

 accepted opinions. The present paper 

 is a brief rejoinder to that article, pre- 

 pared with special reference to its bear- 

 ing upon the Appalachian and White 

 Mountain forest-reserve bill. 



The paper of Colonel Chittenden is 

 exceedingly well written and upon first 

 reading might seem to contain strong 

 arguments against the regulative ac- 

 tion of forests. Upon analyzing its 

 statements, however, it will be per- 

 ceived that Colonel Chittenden prac- 

 tically acknowledges most of the claims 

 made for forests, that the paper con- 

 tains many contradictory assertions and 

 illogical deductions, and that his argu- 

 ments are largely conjectural and un- 

 accompanied by proof. 



The paper states that the commonly 

 accepted opinion is that forests have 

 a beneficial influence on stream flow : 



"(i) By storing the waters from rain 

 and melting snow in the bed of humus 

 that develops under forest cover, * * * 

 preventing their rapid rush to the 

 streams and paying them out gradually 



*Being mainly a rejoinder to the paper of Col. H. M. Chittenden, U. S. A., entitled 

 "Forests and Reservoirs in Their Relation to Stream Flow, With Particular Reference to 

 Navigable Rivers," presented before the American Society of Civil Engineers. 



Prepared at the request of His Excellency Curtis Guild, Jr., Governor of the State of 

 Massachusetts. 



489 



