Mr. Chitten- 
den, 
532 DISCUSSION: FORESTS, RESERVOIRS, AND STREAM FLOW 
The writer based his findings solely on data found in the paper by 
Messrs. Clapp, Murphy, and Martin.* He has since examined the 
Weather Bureau records, but finds nothing to modify these data, while 
they confirm the writer’s views as to the course of the storms that 
produced those very heavy run-offs. As to the American River water- 
shed, Mr. Pinchot’s figures and the writer’s practically agree, although 
Mr. Pinchot has added several stations outside the water-shed, not 
used by the writer. On the Puta Creek water-shed, of the eight sta- 
tionst used by Mr. Pinchot—(76), (74), (17), (71), (77), (6), (78), 
and (72)—six—note carefully the number and location—are outside 
the water-shed, not including Calistoga. The use of so large an ele- 
ment from the outside would, in any case, be questionable; in the case 
under consideration, when the conditions are understood, it is inde- 
fensible. All these outside stations lie in the Sacramento flood plain 
except Guinda, which is a short distance in the hills. The storm con- 
ditions on this plain are entirely different from those in the valley 
of Puta Creek. That valley has always been noted for heavy rain- 
falls and enormous run-off. Messrs. Clapp, Murphy, and Martin say 
‘that “in the region about Clear Lake and Mount St. Helena, in the 
Lower Sacramento Basin, the precipitation is remarkably heavy, and 
occurs almost entirely as rain.” The storms sweep in from the 
Pacific, break over the hills directly upon this valley, and drop the 
bulk of their burden in passing. The intensified character of these 
storms is thoroughly understood locally, and must be taken into ac- 
eount in any rational determination of their effects. 
The storms in the Sacramento plain are entirely different. Sweep- 
ing up from the south, their precipitation is very much lighter than 
on the hills on either side. This is well shown in the records of this 
storm. Taking all the stations in the plain from Chico to Suisun, the 
maximum precipitation for the 10-day period is less than 6 in. in all 
but one or two instances. The use of these stations in any way in 
determining the precipitation on the Puta Creek water-shed is inex- 
cusable, much less the assignment of 75% weight to them. A rail- 
road engineer who would estimate in this way the flood flow of Puta 
Creek, in the absence of discharge measurements, and provide flood 
capacity on that basis under a bridge that he might be called upon to 
build, would be guilty of gross professional malpractice. The writer 
took the only records he had which directly covered the case, but he 
did not rely on them alone. At many of the stations, Messrs. Clapp, 
Murphy, and Martin gave 1904 flood readings, and there is a close 
correspondence running through all the records, between the 1904 and 
* Transactions, Am. Soc. C. E., Vol. LXI, p. 281. 
+ Mr. Pinchot does not specify the stations used in his determination, but he gives them 
in a letter to the writer as follows: Calistoga, Davisville, Dunnigan, Guinda, Helen Mine. 
Sacramento, Vacaville, and Woodland. The numbers on Fig. 17 are the designations used 
by Messrs, Clapp, Murphy, and Martin. 
