Evening star. [volume] (Washington, D.C.) 1854-1972, 1913-08-17
FLOOD PREVENTION
Control of the Mississippi and
Its Tributaries.
HOLD BACK HEAD WATERS
The Reservoir Method of Checking
Unusual Flow and Protecting
Property Along Streams.
mes J. Hill, in Review of Reviews.

James j. Hill, in Review OF Reviews.
The complete control Of floods on the
Mississippi river and its tributaries would
seem to he possible. given right method
and a sufficient amount of money Ii
presents single problem and not a series
of disconnected ones Because il has been
regarded in the latter light. little has yet
been done toward it's solution.
Experience has shown that levees make
no permanent improvement. AS the cur
rent of the river slackens toward its
mouth, a great mass of silt borne by II
| is deposited. This raises the level of the
| river bottom. Where levees confine the
water within a narrower area. the de-
post is deeper. and the river bed Is lifted
eventually above the level of the sur
rounding country. Therefore they must
be built higher every few years. Each
break in them is now a more serious at
fair. There comes time when no in
genuity and no labor can save the valley
from destructive inundation. China has
followed this system for centuries, with
results that show IL a disastrous failure.
There is. or should be, scientific
method of flood control. Its central idea
Is not to provide a channel on the lower
course of river able to carry off its flood
volume. but to prevent any more water
from reaching the lower channel. at any
season, than 1t can carry to the sea with
out breaking or overflowing its banks.
! Engineering skill can settle the details;
and if enough money is provided they
can be carried out
Suppose the number of cubic feet per
second that the present channel of the
Mississippi can carry safely on its lower
reaches to be ascertained. Then suppose
the number of feet to be ascertained that
will come down during the greatest flood
ever known. The difference, of so many
| cubic feet per second. is the surplus to be
| taken care of. This must not be allowed to
| reach the Mississippi until time when
| 1t can do no. harm. The excess of the
| flood season must be held, and released
gradually during the period of average or
| low water in the channel
Calculating the inflow from the tribu-
| taries of the Mississippi separately, SO
many cubic feet may be assigned to each
of them as will produce the total fixed
as the safe limit for the main stream.
| These amounts, Of course, would be pro-
portioned to the total flood flow of each
tributary. Again. the difference between
| the flood discharge and the amount as
signed as safety maximum shows
mathematically how much water must be
| held back on each to make sure that
| the Mississippi can never again reach
| the danger line.
| Starting at the mouth Of each tributary
| with it's allotted maximum flow, the
| amount that should be held back some
where on each Of its branches may be
| found in the same way. This can be re-
| peated until the head waters OF every
| affiuent large enough to be taken into
| account have been reached. Thus. by a
| process Of elimina t!on II would be dis
covered exactly how much flood water
| must be impounded in each case: and the
| topography, Of the neigh5oring country
would determine where 1T could be re-
| tanned.
| \ map of the Mississippi and it's
| branches after this process has been
| completed would resemble a great tree
| with a series of reservoirs of different
| capacity dotting It's branches to the
source of the remotest tributary. On eacn
| would be marked the capacity required
TO hold back its share. This is a work
| for which modern engineering science Is
| competent. When 1t ..as been done, and
| only then, should or can construction
| begin. Anything less than this is mere
hand-to- mouth work; throwing money
into the flood each season, to be swept
away the next, with an unceasing tribute
| Of property and life.
Begin at the Sources.
| The place to begin, after the estimates
ard surveys have been made, is not the
| lower Mississippi or the navigable
| streams that flow into It, but the sources
of all the tributary watercourses. The
| undertaking is so tremendous that only
the federal government would be equal to
it. Although, much of this work would
be on streams that have no nayigable
value. the states cannot and Will not
stand behind it: since, in many cases,
those to benefit are not those in which 1t
| must be done. Therefore the general
government must be relied on; and even
for ii the work would be greater than
Panama.
Where dams are constructed across
streams to make impounding reservoirs.
power will be created which, if wisely
and honestly used, would return an in
come on a considerable portion of the
| outlay. But the great and sufficient in
ducement must be the absolute preven-
| ton of flood disasters for all time to
| come. And if the total flood losses in the
| interior basin whose waters now to the
| Mississippi were computed for the last
| fifty years they might possibly justify
the immense expenditure required.
| The sums spent on farcial river i'm
! provement in the same time, for the al
| legged benefit of a non-eXistent commerce.
| would go a long way toward carrying
out this beneficent work. When finished
| it would complete all practicable i'm
prOvement Of our streams for navigation
| as well as for flood protection. But the
! first essential is to adopt one compre-
/ hensive plan and work to it, when it was
| found that one trunk line between New
! York and Chicago could not carry the in
1 creaSlng business. QOuDle-Qeck railroad
| had been built, with a new track hung
| on stills above the old one, and If still
! another story had been added fast as
business grew, 1t would have been par
| allel. in theory and in costly failure. to
| the nations work on the Mississippi.
Since We cannot multiply channels. as We
do railroad tracks, the only recourse In
| dealing with floods is to reduce the vol
| ume of water coming down.
| That this could be done in the way sug-
gested seems reasonably possible. 1t
would be a stupendous engineering pro-
| ject because each detail must be cal
| culated and adjusted with reference to
| the whole plan. Experience has shown
| that a weak reservoir increases flood dam
gers If one gives way. 1t may carry
| with it a whole series that would have
| stood but for the additional strain put
upon them And the damage wrought by
a broken reservoir is often greater and
more awful than the ravases of any
food not thus intensified in volume and
violence. Therefore each dam would
h;rye to be built as solid as science can
make it. with large margin OF SAFETY
above the limit of any strain to which
nowage and food statistics show II to be
| liable in the most unfavorable season.
p Il IT,