The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1914-11-26
YUKON RIVER REPORT
RANKS FIFTH IN LENGTH
uAs SMALL DISCHARGE coMPAR.
ED WITH ITS DRAINAGE
TERRITORY.

The Yukon river in Alaska is one of
the great rivers of the North Ameri-
can continent. A brief report on the
discharge Of Yukon river at Eagle,
Alaska, by E. A. Porter and R. w. Dew
export, has just been issued by the
United States geological survey as
water supply paper 345-F. Probably
few people have an adequate concep-
ton of the size Of this river and char
acteristics of its flow A. H, Brooks,
of the geological survey. gives the Yu-
kon fifth place among the large rivers
In North America and estimates it's
drainage area at about 100000 square
miles. It's length, including the Lewes
and Teslin rivers, is given in the re-
port as 5000 miles. This may be COM
pared with 5000 miles for the Mississ-
ippi and Missouri. 1868 miles for the
Mackenzie, 1000 for the Colorado COM
bined with Green river, and 1900 for
the Ohio combined with the Allegheny.
Compared With Other Rivers.
The discharge of the Yukon varies
from a maximum of 254,O0O 20 mini
mum Of 1O,100 cubic feet second or
an estimated average flow of 1920
cubic feet. This is relatively small
discharge, the average flow of the
Mississippi being 695,0OO, that of the
Ohio 100000 and that of the Colorado
2S,3O0 second-feet. The Nile with a
drainage area of 100000 square miles
has an average flow of 10000 cubic
feet second. The flow of the Yukon
is therefore relatively small as related
to it's drainage area, and this appar-
ent anomaly is accounted for by the
fact that the interior of Alaska has
the small rainfall characteristic of that
portion of the United States which lies
between the Sierra Nevada and the
Rocky mountains, north Of the latti-
tude Of Salt Lake City.
Closed and Open Seasons.
Navigation on the Yukon has so i'm /
portant a bearing on transportation in
interior Alaska that it has given rise
to a general recognition of two sea-
sons-the closed season, when the Yu
kon is either filled with floating ice or
frozen over and the open season. The
breakup Of the ice usually occurs
about the middle of May, after which
the river Is open to transportation for
five or six months, or a little longer
The breakup is not only an event OF
great economic significance to the in
habitants In the interior of Alaska but
1t presents features of great dramatic
interest as we'll. One who has not wit
messed it, according to the authors OF
the survey report, can hardly imagine
the impressiveness of the spectacle
From bank to bank the surface of the
river is a solid mass Of huge moving
cakes Of ice cakes, which are constant
ly grinding and disintegrating with an
awe inspiring exhibition of resistless
force.
The freezeup is less spectacular.
With the increasing cold of the au-
tumn slush ice forms in the river and
as the cold becomes more intense the
Ice increases in volume until finally II
Is sufficient to bridge the entire stream
This means the termination of naviga- {
lion on the Yukon until the following
May.
How Measurement Was Made. {
The geological surveys measure I
nents of stream flow near Eagle were
made during the winter at a point '
about two miles above the town, where T
he river is 1900 feet wide by cutting =
roles through the ice at intervals OF u
70 feet and making soundings. In this q
way the exposed section of the river r
vas determined, and the velocity Of r
he stream at each hole as determln- Z
d by a Price current meter. During
he period of breakup discharge the c
were made by means =
# Ice floats. In the open season the !
low was determined by the same +
method as on any large river. +
The maximum discharge measured ;
n 1911 was on May %, when the vol q
lme was $4,000 second-feet. The +
width Of the water surface at the r
Measuring section was 1645 feet and i
he greatest depth of the river was 2S.1 :
eet. The average surface velocity n
vas SIS miles an hour. n
, A copy of this report may be OBTAIN Q
d on application to the director of the q
United States geological survey, Wash n
ngton, d. C. II