16 B. Silliman on the Deep Placers of 
and although the waters of this considerable reservoir are not 
now flowing in either of the canals under consideration, I am 
credibly informed, on high authority, that they are likely to do 
so ere long. Cail n Creek Lake (called on the map Hureka 
Lake) is the most sekeiierais reservoir of the Eureka Lake © 
Canal Co. I visited it in November, after the first fall of snow, 
but before the waters had commenced accumulating. In four 
or five weeks time after it was = A substantial dam built of — 
blocks of granite, raises its waters to a present average height of _ 
forty-two feet above its outlet, me natural | of granite 
capable of receiving twenty feet more of t. Its base is 
transversely at bottom one hundred and ime feet, its height 
seventy feet, and from bank to bank its top measures two hun- 
dred and fifty feet. The water face is protected by a double 
covering of sawed planking, securely fastened, and in all five © | 
inches in thickness. The flow of water is regulated by a sluice- 
way of arched masonry. When full, the present capacity of this 
reservoir is estimated at 933,000, 000 cubic feet of water, By an 
increase of twelve feet in the height of the dam, Mr. _— esti- 
mates the iseaebed capacity of this reservoir to be 2 2,000,000 
of cubic feet of water, equal to twenty-five days ier of the 
canal with a constant stream, or in all about six months’ supply. 
But the canal receives its supply for four months, say from 
pod middle of April to the middle of August, from ‘the moun- 
streams, which afford a plentiful supply from the constant 
aneeing of the snows during this season; the snow accumu- 
lates in great quantities in the snowy Sierras during the winter 
months, the melting of which supplies not only the flow of the 
streams, but fills also to overflowing all the mountain lakes and 
cial reservoirs, in which the waters are kept in reserve 
against the droughts of late summer and autumn. Rarely, asin © 
the a of 1863-4, does the snow-fall fail to meet the ~ 
mands. ring the year named, for the first time since the 
struction of “the canals, the reservoirs were not half fille d, but aa 
current year they were filled again by mid-winter. The — 
rain-fall for 1863-4 was less than has been known in California _ 
since 1850-51. The snow in 1863-4 measured only four feet.* 
a Mr. Black gives the following table, &e. 
intent of the Rain-fall, as registered - Sacramento for fifteen years : 
pence: 
ear. Rain-fall in inches, | ar. in inches. 
1849-50 . wee BB. 1857-58 - 15.008 
00-D 1 ig ee 4.730 | 1858-59 16.021 
1851 ae ited 1859-60 22.107 
1852-53.... nt eee eee! 1860-61 16.097 
; oe eae | 1861-62 35.549 
1854-55 ... seane3.620 | 1962-6: 11.579 
1 56... vid 8270 | 1 34 rer y 
1856-5 rs 10.443 | Mean rain-fall, 18.64 
From this table it will bet seen that the rain fall for 1863, ’64, is only 7.37, whilst — 
ee 
