DISCUSSION: FORESTS, RESERVOIRS, AND STREAM FLOW 37% 
W. H. Lerrinewewy, M. Am. Soc. C. E., and A. M. Srrone, Assoc. 
M. Am. Soo. C. E. (by letter) —Colonel Chittenden’s deductions in 
regard to the action of forests on floods are borne out very markedly 
in the streams of the Southern Sierras. 
The control of the flood flow of these streams is of nearly as great 
commercial importance as that of the navigable rivers of the Middle 
and Eastern States. Various national, municipal, and private projects 
are affected by large and sudden fluctuations in the flow of the streams 
on which they are located. It is claimed that the floods are largely 
affected by the conditions of forest cover, and can be made less serious 
in many places by building up the forests. The Sierra Nevada 
Mountains, in California, upon the streams of which the State depends 
largely for its prosperity, have been the scene of floods which have 
eaused great damage in recent years. This entire range has been 
placed in the National Forests, in order that the forest cover may be 
preserved and nurtured under Government control, and beneficial 
effects are hoped for. 
Four of the principal streams in the Southern Sierras have been 
gauged by the Government, thus obtaining definite data on their flow. 
These are the Merced, Kings, and Kern Rivers on the western, and 
the Owens River on the eastern slope. The characteristics of their 
drainage areas are described as follows:* 
Merced River—Merced River drains the middle portion of the 
western slope of the Sierra Nevada Mountains with a drainage area 
of 1090 sq. miles. The topography of the country is rough and 
rugged, and, in this basin, is the famous Yosemite Valley. The 
formation is of granite, which, on the upper reaches, rises in pre- 
cipitous domes and peaks, smoothly marked by glacial action. The 
middle reaches of the basin are well timbered and contain the Mariposa 
Grove of big trees. The timber growth extends well down on the lower 
elevations of the foot-hills, where the covering is of brush and grass. 
Numerous lakes are scattered over the upper portions of the basin. 
The mean annual precipitation is from 25 in. in the foot-hills to 60 in. 
in the higher elevations, where it falls in the form of snow. The 
gauging station is at the lower edge of the foot-hills. 
Kings River—Kings River drains a portion of the western slope 
of the Sierra Nevadas, quite a little south of Merced River, and has 
a drainage area of 1742 sq. miles. The crest of the Sierra Nevadas 
at the head of this basin reaches an elevation of more than 14 000 ft., 
and forms the most rugged portion of the range. A large number of 
small lakes on the higher elevations are fed by small streams from the 
perpetual snow banks and glaciers. The formation is granite, which, 
above an elevation of 10000 ft., is bare. Below this elevation there 
is a heavy covering of timber and underbrush. Extensive groves of 
*“ Progress in Stream Measurements,” U.S. Geological Survey. 
Messrs. 
Leffing well 
and Strong. 
