Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1891-01-17
A RESERVOIR ACTION
Not Only a Fact, but Such Ac-
ton Can Be Much Aug
mented by Art.
ANY NUMBER OF EXAMPLES
From the Smallest Br0Oklet to the
Mighty Father of Waters.
AN ILLUSTRATION FROM ARIZONA,
Which Fortunately Came Under the OBJ
servatiOn of an Engineer.
ANY NUMBER OF EXAMPLES
In ILLUSTRATION FROM ARIZONA,
ONE SUGGESTION FOR THE FARMERS
PAPER NO. s.


The proposal to utilize and augment by
art the reservoir action of water courses, and
thus to mitigate food conditions, and at the
same time develop inland navigation to the
fullest possible extent, was expected to be
regarded as a reconciliation and extension
to larger uses of well-established principles
of hydraulics.
1t was of course expected and desired that
engineers would criticize the devices sug-
gested to be employed; and analyze the re-
lations of the food volumes to the reservoir
volumes practicable TO obtain in the river
channels; in other words, the efficiency of
the proposed measure.
Most valuable facts not generally known
data not accessible to the most laborious
research-would be brought out in this way,
and probably in no other.
1t was not, however, anticipated that any
engineer, much more any hydraulician,
would question the fact of reservoir action
in water courses, or regard it as a new idea
or discovery. That this has occurred seems
10 justify more technical treatment of the
subject than was originally contemplated.
Reservoir action is a fact; and it is a fact
that such action can be greatly and most
benehcially augmented by art. How much,
in what ratios to food volumes, with what
good results, are questions OF fact for prac-
teal men to determine by surveys, observa-
tions and calculations Criticism on these
lines is practical and must be beneficial to
the public interest
Floods Make Reservoirs.
No observant person can deny that the d.
mensions of a water course are mainly de-
pendent upon food conditions The effort
Of streams to enlarge their channels to ac-
commodare the extreme food wave, is fact
easily recognized. Everyone has seen
tiny riTulet, at morn traversing the surface
OF gentle sloping meadow. at noon become
a raging torrent by a cloudburst or unpre-
cedented rainfall, and next day, shriveled to
It's original proportions, trckle along the
bottom of deep gully, yards in width and
depth, sunk in a few hours by the torrent of
such short duration. A small stream
is taken for illustration, because rel
atively great changes in the bed
OF such streams are quite common. Large
streams and rivers behave similarly under
similar conditions, as is instanced in the
constant changes in the bed of the
Mississippi, and most strikingly in the
recent great changes in the San Pedro river
In Arizona.
Unusual natural phenomena seldom
occur under the immediate observation of
scientific men, as fortunately happened in
this case. A distinguished engineer, who
was on the ground, related to the writer
what is here put down from memory. On
the night of the occurrence DR.. p. and his
party spread their blankets In the chapparal
about quarter of mile from the town of
DudIeyville, and as far from the San Pedro,
The town is built against the foothills at
one side OF a wide fiat, on the opposite side
OF which flowed the river. During the
night the party were compelled to move
back three times; and when morning
dawned were in the town, the entire fat
having been washed away.
All night ana part OF the next day the
banks fell with the noise of thunder. melted
away in the torrent and were gone. A
tract several hundred yards wide. by several
miles long, was washed out to an AVERAGE
depth OF II ieet, millions of tons being re-
moved in "a hours.
An Arizona Illustration,
This occurrence well illustrates the ertsnt
TO which a single unexampled food will
alter and enlarge water course as has been
done IN Arizona this year by the unprece-
dented rain tall. The natural action of
water on river bed is to establish it with
the slope at which erosion ceases; and ex-
treme food conditions, if repeated at longer
or shorter intervals, tend not only to
deepen the channel, but also to enlarge it
latterally; SO that if the original fall be
great enough, the banks and bed sufficiently
erOdable, and the length considerable. the
reservoir capacity finally attained is sufi-
cient, or more than sufficient, to accommo-
date the entire volume of the greatest floods.
The cyclic uDcomprehended natural