The San Francisco call., 1904-06-06

|
.ss--
American River will be given in detail
as peculiarly illustrative of the situa-
tion. The American River has its con-
luence with the Sacramento River at
the city of Sacramento. The mouth of
the American River is in township 8
north, range 4 east. 1t has three we'll
defined river channels in township 13
north. range 10 east. The surveys of
the Government show that the distance
between the mouth and the well-de-
fined sources of this river is but fifty
four miles and these sources are 5000
feet above the mouth of the river.
1t is difficult to realize, but 1t is
mathematically true, that a horizontal
line fifty-four miles long drawn from
the head waters of the American down
to it's mouth would stand 6000 feet
above the city of Sacramento. and the
river channel must take up all of this
fall in its course of less than seventy
five miles, even by way of the channel
itself Here is an important tributary
of the Sacramento River. having an
average fall of eighty feet to the mile.
delivering it's rainfall and its snow
melt into a channel which, from that
point to the sea. has less than three
inches of fall to the mile.
The upper courses of the American
River have more than double the an
nual precipitation of that recorded at
the city of Sacramento. Graphically
presented, then, draw two straight
lines, one running north 275 miles and
the other south $50 miles to a point of
junction, where they turn at right an
giles west to the sea through a single
combined channel; then from the high
SUBMITS of two mountain ranges draw
the continents at right angles with the
central drainage and with the central
axis of the mountains; give these trib-
utaries a declivity of from sixty TO one
hundred feet fall to the mile and give
their catchment areas double the an
nual precipitation of the lower courses
Of the main drainage and we have
series of torrential streams delivering
flood volumes in a comparatively few
hours into channels which possess the
very meager and limited drainage ca
pacity of less than three inches fall to
the mile.
TIDE STOPS CURRENT.
When a tide moves eastward through
the Straits of CarquineZ drainage of
the great basin is entirely suspended
and, as already shown, there is an OBJ
structing tidal influence for at least
one hundred miles up the channels of
both rivers. Thus the low stage of
Suisun Bay affords all the drainage
these rivers can by any possibility
have. But the elevation of Suisun Bay
is determined by the relation of the
sea to the bay system and the lower
courses of the rivers cannot be changed
or modified except by a change of the
sea level itself.
Owing to the greater rainfall upon
the catchment area of the Sacra-
mento, it's flood stages are often higher
than those of the San Joaquin. The
observation of this phenomenon has
led to the fallacy of supposing that
the Sacramento might be relieved by
turning its waters into the channel of
the San Joaquin by an artificial canal:
that is. invoking the aid of the San
Joaquin in the drainage of the
Sacramento. But the sea level status
of Suisun Bay is the controlling
factor when drainage is considered
When the waters of these rivers reach
Suisun Bay they are subject to the
same law; therefore, the proposition
to empty the waters of one into the
channel of the other is attended by
the absurdity of supposing that
river may empty itself by delivering a
part of its current into its own chan
mel. Both rivers find a common and
paramount obstruction in the ocean
tides of Suisun Bay.
Professor McAdie stated to the
recent River Convention that If the
great storm of last winter had con-
tinued three days the flood waters of
the river would have extended from
the foothills of one range Of mountains
to those of the other, submerging the
entire valley. This, indeed, is just
what did happen in the flood of Feb
ruary, 1861.
The meteorological conditions to
which the recurrence of great floods
In the interior basin are referable are
familiar to all the residents of the
valleys. One foot Of newly-fallen snow
is equal to one inch of rainfall, but
when ten feet OF snow is found it
equals fifteen or eighteen inches of
rainfall, because the snow has COM
raCted by its weight. When the up
per courses of the tributaries of the
Sacramento lying from 5000 to 5000
feet above the central drainage of the
valley contain from five to ten feet of
snow and receive a precipitation of
fl ON ten to fifteen inches of rainfall
within three days that carries off the
snow, the water is delivered to the
drainage channels of those tributaries
as rain runs off the steep roofs of
houses.
RECEIVE THE FLOODS.
The Sacramento and San joaquin
are tidal rivers for nearly 100 miles of
their lower courses and must receive
these torrential floods and deliver
them to the ocean through channels
which have but thirty feet fall in 125
miles.
Thus it is that after an American
occupancy of ffty-five years, the prob
lem of drainage remains unsolved
But little has been learned and alb
solutely nothing has been done TO