The record-union. [volume] (Sacramento, Calif.) 1891-1903, 1897-04-11

.C}N TN
II
usefulness would be beyond possibility.
NATURAL AND HUMAN ENERGY.
It is by the application of these prin-
ciples, assisted by the skill and energy
of man, that we may expect to improve
the drainage of our great valleys.
FRICTION OF RESISTANCE.
We have, in the early part OF this
paper, referred to the effect of friction
or resistance upon the flow of a stream
or the movement of a body down an
inclined plane. To illustrate the i'm
portance of this question in the flow Of
water, let us give an example:
PRACTICAL ILLUSTRATION.
A canal 1900 feet wide and 10 feet
deep will have a cross-sectional area
of 10000 square feet. Let the condi-
tons be such that the friction or re-
sistance will be about what has been
determined for canals or rivers in good
regime. Let the Slope or fall of the
stream be q inches per mile, then ac-
cording to a well-known formula for
calculating the flow Of water under the
above conditions, the canal would dis
charge 43, 800 cubic feet of water per
second.
RESULT OF CONTRACTION.
Now, let us contract this canal to a
width Of 1000 feet, with a depth of 20
feet. with the same slope and same
cross sectional area, viz, 10000 square
feet. Then, according to the same
formula, the discharge would be r.
500 cubic feet per second, or about one
and two-thirds times more water pass
ing through the latter canal than
through the former We find further
that the velocity in the first canal
would be 2 II feet per second while
the velocity in the last canal would be
3.64 feet per second
Again. if we contract the canal to a
width of 500 feet and give it a depth of
40 feet. with the same fall or slope
as in the first instance above given,
then we have an area of 10000 square
feet, velocity of As feet per second
and discharge of $4,000 cubic feet
per second-over double the discharge
of the first canal above given.
TWO PRINCIPLES OF DRAINAGE.
We have. therefore, discovered two
principles by which we can improve
the drainage of country, viz: First,
by increasing the slope or vertical dis
lance through which the water de-
scends second, by increasing the depth
of the canal, ditch or river through
which 1t flows and diminishing the
width or fractional area.
PRINCIPLE DEMONSTRATED.
This latter principle is thoroughly
demonstrated by the flow Of water
through all kinds of pipes If, for in
stance, we desire to supply a smaller
pipe with a greater fail with water
enough to fill it when running from a
pipe having a smaller fall, we must
enlarge the supply pipe, and by en-
larging the supply pipe we increase
it's volume and reduce the FRACTIONAL
area, although the grade or fall per
foot may be much less in the larger
than the smaller pipe.
These principles we find admira bly,
illustrated in nature.
FORMATION OF DELTAS.
A siltbearing stream, running over
a delta formation of it's own contin-
ues to deposit material on the sides and
in it's bed until each foot of the in
clined plane broken as it may be. has
obtained such an elevation as to give
the water sufficient velocity to resist
the further deposit of silt in the bed
of said river. This would be true as
to ell-aligned channel with given
volume of water. But, unfortunately
for man, rivers or earthen channels, do
not always have uniform channel.
In some cases the channel widens out
in others il becomes narrow, accord
ing to the power of the material
through which it flows, to resist the
impact and securing power of the
water. Whenever the channel becomes
wider than the volume of the water
demands TO give it velocity to remove
it's material. then shoaling begins. and
as the shoa,ing increases the river
loses it's velocity and gradually fills I'M
til finally it may branch and form two
or more streams. thus causing the
formation of deitas on the conrary, if
the channel from any cause becomes
narrower, then the bed OF the
river gives away before the
impact Of the water and the stream
becomes deeper, and the deepening pro
cess continues until the resistance of
the bed of the stream Is equal to the
force of friction and impact of the
water on the bed of the stream.
AS an illustration of this principle,
we cite the Miss issippi River.
THE MISSISSIPPI RIVER
The Mississippi River at Carroliton or
New Orleans is 2.6.3 feet wide, with an
I average Cepth Of 1856 feet. 1t has at
this point a fail of one and three-ifth
inches per mile, with q cross.sectionai
area of 1a,96S square feat. This river
discharges 1.lo2..,.19 cubic feet of water
per second with velocity OF 5.92 feet
per second. At Nicksburg the depth is
100 feet: the fall four inches per mile
and the observed velocity 6.9J feet per
second; width, 2.129 feet, and the dis
charge about the same as at Carroll
| ton.
At Columbus, below Cairo, the width
of the river is 2,21i feet. depth So feet,
cross-sectlonal area 14S042 square feet,
with a velocity of 6957 feet per second.
The fall per mile is i3 inches We
| therefore observe that with a shallow
river we increase the fall per mile to
make II carry the same amount of wa
| ter that a deep river with only one and
| three -fifths inches fall per mile dis
| charges. Reverse this rule; make the
/ river deep with the same fall per mile