The morning call., 1890-10-24
ARE RIVERS sHOALING

Attention has once more been called to the
gradual shoaiing of rivers in the western por-
ton of this continent, and the prediction is ut
tered by an engineer that the effect of irr-
CATION will be to render some of our princ-
pal rivers nOn-navigable. The engineer de-
clares that within the next ten years the
Missouri will have been 50 depleted by irri-
CATION canals that 1t will cease to be naviga-
BILE even by the smallest craft.
This is a matter of importance and in con-
sidering it it is we'll to go slowly and to make
sure of the facts as we GO We may there
fore observe, to begin with, that there are
no irrigation canals to speak of drawing
water from the Upper Missouri, and that.
therefore, the theory that its shpaling is
caused by irrigation rests upon statement
which is untrue. The river Missouri
is naVigable for light-draft vessels for
two thousand miles or more in certain
seasons Of the year. So far as we know
there may be as much water in the river bed
as there ever was within the memory of man.
1t is not pleasant river TO navigate be-
cause it is full of shifting bars on which
there are only q few inches of water, and
from this cause it is not utilized for trans
portatiOn to much extent by the communi-
ties through whose territory it flows. But
the evidence that its volume is gradually de-
crea>ing is not complete enough to warrant
absolute conviction that such is the case.
1t is otherwise with rivers which head in
the high lands further south, such as the
Arkansas, tie Rio Grande, the Platte, the
Kaw, the Smoky Hill, on the east slope of
the range. Ample and indisputable EVIL
dence demonstrates that these rivers are
steadily diminishing in volume. We can
see where ti:eir borders formerly were and
how far they have since rrceded. Their
gradual shrinkage justiies apprehensions
that, like the streams which once filed the
dry arr0yOs of California, they will some
day dry UP altogether, or at all events that
the great rivers like the Arkansas will some
day dwindle to the proportions of the Smoky
Hill, which was once naviGable, but which
the traveller on horseback now sometimes
crosses without even noticing it. The same
shrinkage is observable in the rivers Of Cali
fornia-the Sacramento, the San Joaquin,
the American. the Feather, and the streams
which flow into the ocean in the south
western counties. Ali carry less water than
they did. Whether their volume is still de-
creasing year by year photographers have
net positively stated, but it probably is.
The diminuiion in their case cannot be
ascribed to irrigation, for except in parts of
the San Joaquin Valley and in Los Angeles
and San Bernardino counties the quantity of
water diverted for this purpose has been
small. Some other cause must be assigned
for the phenomenon.
Professors of physical geography have sug-
geSted that the earth's supply of water is
gradually diminishing. that the rivers are
slowly driving up, and that by and by their
beds will be deep ravines with a thread of
water trckling at the bottom To snbstan-
uiate this theory it would be necessary to
show that the shOaling which is observed in
rivers which head in the Rocky Mountains
and the Sierras is likewise noticeable in the
rivers of cther parts of the world. That is
not the case. Data are wanting for exact
comparisons. But, SO far as marine reports
show, the volume of water in such eastern
rivers as the ST Lawrence, the Hudson the
Delaware, the Mississippi is about as copious
as it was when America was first settled by
white men; nor are there any records
which create a suspicion that in ancient
times the depth of the Old World rivers,
such as the Krone, or the Nile. or the Volga,
or the Gauges, or the Euphratrs was greater
than it is to-day. From obvious causes,
rivers shoal as they pass large cities; but
with the exception of Western America
there appears to be no reason for believing
thai The great rivers of any portion of the
world carry lyss water to the ocean than
they did at any former historic period.
Why this portion of the globe should con-
stitute an exception, it is for scientists to
discover. SO far as we can guess from III.
meager statistics which are at our command,
the rainfall is as copious rs il ever was in-
deed. the development of agriculture must
render that 4 certainty. Why, then, has the
Sacramento lost so large proportion OF its
volume since tbs FIRST discoveries Of gold,
and why is the Arkansas. which was once a
mighty river in Lake County, Colorado,
mere dribbiing r!vuet?