DISCUSSION: FORESTS, RESERVOIRS, AND STREAM FLOW 343 
been the experience on the Lower Mississippi, that only one species Mr. Todd. 
of timber will have the slightest effect. Cypress trees, where they occur 
in considerable numbers, and where their roots extend far below the 
natural surface, have been the means of checking the caving in a few 
localities. However, the cypress has less value as a conservator of 
rainfall than any other tree found in the delta. 
With reference to “reservoirs and their relation to stream flow,” 
undoubtedly, they are more intimately connected with river regula- 
tion than forestry, yet, as a means of affording material relief from 
floods, especially along the Lower Mississippi, the writer is forced to 
the conclusion that in the main their influence can be but little felt. 
This conclusion is reached after a very careful study of all available 
data, together with an intimate experience with floods, and from a care- 
ful observation of their inception and propagation through the valley. 
Yet the hope is held out, by some of the advocates of the reservoir 
system, that it will be the means of solving the flood-control problem 
along the lower valley. The following is quoted from a paper* by 
A H. Horton, Assoc. M. Am. Soc. C. E., Assistant Engineer, U. 8S. 
Geological Survey, entitled “The Effect of the Conservation of Flow 
in the Ohio Basin on Floods in the Lower Mississippi’: 
“This paper is the result of an attempt to determine from a review 
of actual records the contribution made by the Ohio basin to Missis- 
sippi floods, and the effect produced on the latter by flood conservation 
in the former. The following facts are shown: 
“(1) That the Missouri basin, by reason of its great area of flat 
country, is slow-spilling and floods therein do not rise with rapidity 
sufficient to gorge the channel of the Lower Mississippi. 
“(Q) That the Upper Mississippi basin, although subject to more 
rapid fluctuations in flow than the Missouri, is very much smaller 
than the latter and could not originate floods of capacity sufficient 
to gorge the Lower Mississippi. : 
“(3) That the Ohio basin discharges at maximum flow 50% more 
water than the Missouri and Upper Mississippi combined, and as the 
basin is a quick spilling one, it practically alone is the cause of floods 
in the Lower Mississippi. 
“(4) That inasmuch as it has been shown possible to reduce floods 
in the Ohio, the same means will also reduce to a point well within 
the capacity of the Lower Mississippi channel all the floods that are 
likely to visit that channel.” 
Checked by actual occurrences, only the second of Mr. Horton’s 
statements can be accepted as a fact. There have been times when the 
Missouri, practically alone, has “gorged the channel of the Lower 
Mississippi,” or, as the writer understands the above term to mean, 
the exceeding of the overflow stages. The second flood of 1903, cited 
by Colonel Chittenden, is an example: Originating almost entirely in 
the Missouri Basin, the flood stage was equalled or exceeded at almost 
every point from Cairo to New Orleans, notwithstanding the fact 
*Hngineering News, June 11th, 1908. 
