DISCUSSION: FORESTS, RESERVOIRS, AND STREAM FLOW 423 
W. D. Picxert, M. Am. Soc. C. E. (by letter)—Colonel Chitten- mr. Pickett. 
den’s paper and the paper by the writer entitled “The Floods of the 
Mississippi Delta: Their Causes, and Suggestions as to Their Control,’* 
indicate to the casual reader a radical antagonism, apparently, as to the 
effect of the shade of forests on the melting of snow; also, as to the 
effect of forests in retarding the flow of rain or snow water on mountain 
or hill sides. It would seem that the first question is whether snow will 
melt faster (especially at elevations of 8000 or 10000 ft. above sea 
level) under the direct rays of the sun, or when protected by shade, 
such as pine forests afford. 
The second question is whether rain or snow water will reach a 
stream when flowing over a comparatively smooth surface, such as 
cultivated fields, in less time than when flowing over a surface ob- 
structed by the roots and trunks of forest trees and by the brush and 
other impedimenta common to all forests. 
It would seem that there is but one answer to these two propositions, 
and that between two engineers, each with exceptionally good oppor- 
tunities for observation of the themes of which they write, this 
antagonism must be more apparent than real, if their views are 
elaborated and explained. 
The object of this discussion is to explain and particularize the writer’s 
views on the subject. In the writer’s paper the cause assigned for the dis- 
astrous floods of the Mississippi Delta was the merging, near the mouth 
of the Ohio, of the “Spring Rise” from that stream with the “June 
Rise” from the Missouri, and the passage of the combined flood toward 
the Gulf. It was also pointed out that the only means of preventing the 
coincidence of these floods at or near the mouth of the Ohio was by 
the construction of reservoirs of the requisite capacity, at the head- 
waters of the Missouri, to hold back the annual floods a sufficient 
length of time to allow the spring flood from the Ohio to pass down 
and out of reach, without peradventure, of the later “June Rise” from 
the Missouri. 
It was suggested that Nature had already pointed out the most 
feasible and effective reservoirs, by the creation of those vast pine 
forests at the head-waters of the Missouri, and that these are vast 
storage reservoirs in which the accumulated snows of winter are pre- 
served until gradually turned into water in summer. These forests 
are usually found in that portion of the Great Continental Divide 
between elevations of 7700 and 9200 ft. above sea level,- usually 
designated the “Timber Belt.” It was pointed out that within this 
timber belt there are vast areas of open land, which were formerly 
covered with pine forests, but which, from unknown causes (supposed 
to be from fire), had become denuded, thereby exposing the snow to 
the direct rays of the sun. The area of these open mountain plateaus 
* Proceedings, Am. Soc. C. E., November, 1908, Vol. XXXIV. 
