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be far better to express — as is so ably done by our Board of Direction
when submitting questions for vote — the reasons for and against
various opinions. It is unwise to assume that we have at any time
obtained all the knowledge possible upon a given subject. If we will
approach the question from this point of view and with full confidence
that the truth in the end must prevail, the opinions of the Society,
when finally expressed, will deserve and receive recognition as
authoritative.

For these reasons, therefore, the writer presents these amendments
for consideration by the Society:

(1). — Page 1221, the third paragraph reads as follows:

"Similar data on many other streams requiring flood control
are lacking, and should be supplied."



FLOODS AND FLOOD PREVP]NTION 1231

In order that it may not appear that the kind of observations already
made are entirely sufficient, which is probably not the case, and as
there are several other items of data required for a complete study,
the writer suggests that the following paragraph be substituted for
that above quoted:

"Extensive studies are needed regarding the physical and
physiographic laws affecting stream loads, rates of transporta-
tion and deposition, and the variation of these factors with
different conditions."

(2). — Page 1224, the first sentence, first paragraph, reads as follows:

"In these discussions the greatest diversity of opinion has
been expressed, and even the advocates of reforestation as a
means of flood control fail to give any quantitative determina-
tion of the effects of forests upon floods."

This is one of the most controversial subjects upon which engineer-
ing and scientific minds have been recently engaged, and inductive
reasoning does not at present result in conclusive proof in all cases
upon either side of the dispute. The writer, therefore, suggests the
following sentence as a substitute for that above quoted:

"In these discussions the greatest diversity of opinion has
been expressed and neither the advocates nor the opponents of
reforestation as a means of flood control have completely estab-
lished to universal satisfaction a quantitative determination of
the effect of forests upon floods."

(3). — Page 1224, the third sentence, first paragraph, reads as
follows :

"The data as to the effect of forestation, soil absorption, and
kindred methods of flood control are not at present susceptible
of quantitative analysis."

Indicating our desire, as previously stated, to stimulate further
research, the writer suggests the following substitute for the above
quoted sentence:

"Intensive study as to the effect of reforestation, soil absorp-
tion, and kindred methods of flood control is needed before quan-
titative analysis will be possible."

(4). — Page 1224, the second sentence, second paragraph, referring to
frozen ground, reads as follows :

"Such conditions prevent the utilization of forestation or
ground storage."

As such conditions prevent such utilization at such times and such
places, only, a more accurate statement is in the language recommended
to be substituted for the above, viz. :

"These conditions prevent at such times the utilization of
reforestation or ground storage."



1232 FLOODS AND FLOOD PREVENTION

(5). — Page 1224, the second sentence, last paragraph, reads as
follows :

"There is a popular delusion that the same reservoir can be
utilized simultaneously to reduce floods, increase the low-water
discharge of a stream, and increase the water-power that can be
developed therefrom, but ordinarily its utilization for any one
of these purposes precludes its efficient use for either of the
others."

As this indicates the kind of indirect adverse criticism which does
not tell the whole story, the following is recommended as a substitute:

"However, the same reservoir capacity cannot be used
simultaneously to reduce floods, increase the low-water discharge
of the stream, and increase the water-power that can be de-
veloped therefrom, but ordinarily, unless there be excess capacity,
the use of the reservoir for any one of these purposes precludes
its complete use for others."

(6). — The remainder of the paragraph just referred to comprises an
entirely unnecessary and unfair discussion, purporting to show that
reservoirs cannot be made useful for flood prevention, together with
other purposes; whereas we know, on the contrary, that, notwithstand-
ing all these statements, it is possible to operate reservoirs with several
purposes in view, and that this is actually done in some of the great
reservoir systems of Europe and America without conflict of interests.
The following two sentences are recommended as a substitute:

"It is evident, however, that such reduced efficiency for a
combination of purposes does have some value, and the maximum
efficiency for each purpose can be obtained by increasing the
capacity sufficiently. The problem is an economic one, and much
information regarding flood frequency, flood damage, reservoir
operation, and comparative values of the several uses of storage
is necessary before it can be satisfactorily solved in any case."

(7). — It is recommended that the first sentence in the first para-
graph on page 1225, reading as follows, be omitted:

"Your Committee, however, does not intend to condemn
in toto the utilization of reservoirs for more than one purpose.
In fact, it believes that" —
Such "damning with faint praise" is entirely vinnecessary, and if
such condemnation is not intended, it will be evident from the expres-
sions, without saying so. The paragraph may well be introduced with
the second sentence by omitting the first five words.

(8). — Page 1225, the third sentence, second paragraph, referring to
the use of detention basins, reads as follows:

"Flood control in such cases is only necessary during excep-
tional rains, and the basin itself may therefore be devoted to its
normal uses most of the time, and only an easement on the lands
occupied is necessary."



FLOODS AND FLOOD PREVENTION 1233

While it is understood that some agricultural pursuits can be car-
ried on within and under the flow line of such detention basins, the
use and occupancy of buildings, especially within their lower depth,
likely to be filled to some extent each spring, cannot be permitted.
Therefore the following is recommended as a more accurate statement,
and as a substitute for the above quotation:

"Complete utilization of the basin for such flood control is
only necessary during exceptional rains and the land of the basin
itself may therefore be devoted to its normal agricultural use
most of the time and only the easement is necessary."

(9). — Page 1225, paragraph entitled (c) : This seems to be a
rather indefinite statement regarding barriers, and the following is
recommended as a substitute :

"Barriers erected across the valleys of tributary streams have
been utilized to retain detritus and prevent its deposition in
the main river. This has been found to be a suitable method
in certain sections of our western country, where the wash of
large amounts of material into the streams had disturbed the
equilibrium and regimen. It is also used in Western Europe.
Where conditions are favorable, this is a practical method of
control, and its use will depend upon the slope of the stream and
the character of the sediment being transported."

(10). — Page 1226, the last paragraph discusses the subject of in-
crease of channel storage between levees. The writer believes that such
storage is ineffective, in view of the fact that the potential storage over
the surrounding country and overflowed lands is much greater than the
volume confined between the levees. Therefore, considering any point
on a stream below the length included within levees, the flood height
is increased and not decreased by the introduction of the levees above.
The writer, therefore, recommends that this paragraph be omitted.

(11). — For reasons which are apparent in the discussion herein-
before given, the writer suggests that the four conclusions on page
1228 be amended to read as follows :

"Reforestation. — The effects of forest growth in preventing
erosion on hillsides are sufficient to justify reforestation for that
purpose, but there has not been sufficient quantitative determina-
tion of its influence on stream flow which would justify a
universal conclusion as to its employment as a method of flood
control.

"Reservoirs and Detention Basins. — At the head-waters of
streams, storage reservoirs and detention basins can be success-
fully employed to reduce flood height. Local conditiojis will
determine which method is preferable. The efficiency, how-
ever, of such agencies diminishes as the distance from them
increases.

"Channel Enlargement, Cut-Offs, and Outlets. — In clear-
water streams, whose banks and beds are not subject to scour,



1234 FLOODS AND FLOOD PREVENTION

these agencies are useful. In streams carrying a large amount
of sediment, whose banks are readily eroded, great care should
be exercised in their employment, always bearing in mind the
fact that on an alluvial stream best conditions follow its con-
finement to a single channel.

"Levees. — The influence of levees as a method of flood con-
trol becomes of prime importance on the lower alluvial reaches
of long rivers and, upon certain streams, may afford the only
method of flood control."

(12). — It is of little avail to submit such conclusions and recom-
mendations without a suggestion as to some definite agency to carry on
such work. Such constructive criticism will be helpful and should be
presented. The writer therefore suggests the omission of the last
paragraph on page 1228 and the substitution of the following, which
should probably occur at the conclusion of the entire report.

"This subject is one of national importance, and while the
work of State and local agencies should not be minimized, the
necessity for the early establishment and unification, under
National control, of systematic rainfall, run-off, and flood ob-
servations in greater detail than at present should be empha-
sized. Such authority should also suggest uniform methods of
observation, co-ordinate information obtained, and preferably
should have these duties as its main purpose, even though con-
struction of important works for realization of results may be
carried on at the same time by other agencies.

"The Committee desires to urge the great importance of the
early establishment of such special agency, supported by ade-
quate appropriations, for the purpose of studying stream regula-
tion in its largest sense, and under whose direction all data shall
be collated, according to uniform standards and systems, so that
appropriate development of the science shall be made."



DISCUSSION" ON FLOODS AND FLOOD PEEVENTION 1235

DISCUSSION



H. M. Eakin,* Esq. (by letter).— The Eeport of the Special Mr.
Committee on Floods and Flood Prevention is a distinct disap- *
pointment to one interested in the general progress of applied science,
wlio had expected the deliberations of the Committee to result in a
constructive policy which would be clear of the inconclusive controversy
that has heretofore hindered adequate progress in river improvement,
and would, therefore, merit the endorsement of the Society and gain
an effectively general support. Essentially, the report is an endorse-
ment of specific projects of river improvement which are the subject
of disagreement among scientists and engineers of standing. It also
carries implications and statements that are not entirely sound.

The general spirit of the report implies that there exists an ade-
quate, esoteric if not general, understanding of the scientific principles
involved in river treatment, and that there is consequently only the
need for such investigations as will furnish additional and standardized
data as to the environment of their operation. The Committee evaluates
with implied authority the relative merits of the various suggested
methods of control, and shows its allegiance to current projects in
statements that are not supported by fundamental scientific analysis.

The value of this implied authority may be indicated somewhat
by an examination of the last paragraph vuider (e), pages 1226 and 1227.
It is indirectly stated that the vise of levees effects an increased channel
storage that induces a lowering of flood levels. This is clearly im-
possible, since the channel storage given by levees is largely in space
above the level which the same flood waters would assume if allowed
to spread unhindered over the flood plain. Moreover, the confinement
of floods between levees increases the facility of flow, so that discharge
to successive reaches is progressively augmented above the normal as
the effects of elimination of normal flood plain storage accumulate,
and flood heights are correspondingly above the normal all the way
to the sea. The increased flood height in the improved reach lowers
the surface gradient for some distance up stream, decreasing velocities,
and correspondingly increasing flood heights. The statement that
levees reduce flood heights by increasing channel storage is obviously
fallacious, yet it is advanced in the report as an important principle,
generally overlooked, but fortunately recognized by the Committee.

The report fails of a much needed mission in not presenting clearly
the present status of the science of streams. It does not indicate the
scientific uncertainty as to the laws that underlie the basic problems
of stream control, the reciprocal variability of discharge, grade, com-
petence, capacity, load, torsional flow, the development, migration,

* Washington, D. C.



1236 DISCUSSION ON FLOODS AND FLOOD PREVENTION

Mr. and elimination of meanders, drainage distances, assortment of debris

^ '"■ and extra-channel deposition — in short, the reciprocally determinative

relation of erosional processes and physiographic forms, and the

possibilities of selective artificial mutation and control of all these

factors.

The problems of stream control reach out into many different
branches of science — geology, physiography, meteorology, hydrology,
agriculture, forestry, and engineering — and involve abstruse laws outside
the scope of these special branches, and as yet imperfectly developed or
only vaguely indicated. No individual or organization has as yet com-
manded such proficiency in all these sciences as to enable them to
outline a programme of river treatment with dependable authority.
Programmes such as have been outlined from the standpoint of a single
science or profession have maiformly failed to withstand scientific
scrutiny from other viewpoints. The result has been controversy,
partisanship, and efiectual inhibition of adequate progress toward the
goal at which all honestly are aiming.

Progress of applied science demands, first of all, a dependable
scientific authority. As regards stream control, we are apparently
without such a basis. The Society probably could perform no greater
service to the Profession and to the cause of river improvement and
flood control than to devise a means of supplying this lack. The
obvioias recommendation is that a special organization be created with
a personnel made up of variously trained scientists and engineers
capable of assembling the pertinent matter of other sciences and of
developing by appropriate researches an adequate, specific science of
streams. The sound development of the science is prerequisite to
its application. Only some such means as suggested can lift the
matter of river improvement above the field of speculation and con-
troversy, and make any considerable advance toward adequate achieve-
ment.

Mr. John W. Hill,* M. Am. Soc. C. E. (by letter). — The frequency
^'"' of disastrous floods in the Central and Western States during the
past 12 or 13 years has directed serious attention to a condition
affecting life and property which can no longer be tolerated. The
periodical floods in the Mississippi and some other navigable rivers
can usually be forecast as to time and river stage, and preparations
can be made to discount more or less the resulting property damage;
these floods or river rises are seldom attended by loss of life. There
is no human foresight, however, which can predict the time of floods
in the smaller non-navigable streams of the Middle West and western
parts of the country, and it is with these that we are at present most
concerned.

* Cincinnati, Ohio.



DISCUSSION OX FLOODS AND FLOOD PREVENTION 1237

Floods in the large rivers of the Mississippi Basin are expected Mr.
every year, although these are not always attended by great property
loss or serious interference with business or transportation. Of course,
there are no known means of preventing such floods. Rain and snow
are bound to fall on the water-sheds, and the waters must flow away
through the streams to the great reservoir in the ocean, to be caught
up again into the clouds by evaporation, to make more rain and snow
at a later date, and repeat the operation of precipitation, run-off, and
stream flow, with frequent floods in the larger streams.

Measures to mitigate the destructive influence of great floods in
the Mississippi River have been inaugurated and maintained by the
States subject to damage, and by the Federal Government, Federal
aid being given in the interest of navigation only.

A discussion of floods in the larger navigable rivers would have
little bearing on the problem of flood prevention in the valleys of
the smaller streams, and, in view of the appalling losses of life and
property which have occurred from these in Ohio, Indiana, Kansas,
California, and some other Central and Western States in recent years,
the people directly affected by the floods have been compelled to insist
on a remedy for an intolerable condition. One remedy would be to
remove all habitations and perishable property permanently above the
flood-plain; but this is not to be thought of as long as other avenues
of escape from flood calamities are open. The vested interests in
public and private property now lying below the flood-plain represent
hundreds of millions of dollars in the States mentioned, and these
must be preserved and protected, if individual property rights in
these river valleys are to survive.

The frequency of destructive floods in the valleys of the smaller
rivers and streams is often under-rated. Thus, in the Great Miami
Valley in Ohio, instead of two or three great floods occurring within
a century (a statement frequently made), at least five such floods
have occurred within 110 years, namely in 1805, 1847, 1866, 1898,
and 1913, the first and last dates marking the greatest floods.

Three of these floods have occurred within the writer's recollection.
In 1866, while living in Dayton, Ohio, he saw the Miami River out
of its banks and flowing several feet deep through the principal streets
of that city. Marks made after the flood of 1913 indicated that, on
Ludlow Street, south of Fifth Street, the flood of 1913 was about
5 or 6 ft. higher than that of 1866. In 1866, however, the city was
much more open — with respect to bridges, buildings, and other obstruc-
tions — to the flow of water in the river channel and through the town,
and the flood discharge for 1913 was not as much greater than
that for 1866 as might be inferred from the difference in flood heights.

In 1866, Dayton had a population of 30 000, and had much unoccu-
pied territory which is now solidly built up; no pretentious structures



1238 DISCUSSION ON FLOODS AND FLOOD PREVENTION

Mr. had then been erected anywhere within the city limits; the river banks
■ were not lined with dwellings or other buildings; and, when the river
rose above the levees, the water found a reasonably unobstructed
channel on the lowlands behind the levees on both sides of the river.

Prior to the flood of 1913, the river banks had been pre-empted
and built on up to the levees, with a street or boulevard between;
several reinforced concrete arch bridges with restricted waterways
had been erected in the river channel, and, in many ways, the free
flow of an overcharged river had been so much obstructed that the
flood discharge of 1866 would have produced higher levels in the city
streets had it occurred in 1913.

The flood of March, 1805, is well recorded for the locality of
Hamilton, 35 miles from the mouth of the Miami River, by a local
historian,* and this flood, in that early day, with no bridges across
the river, an unobstructed channel, and few improvements of any
kind on the river banks, reached a height as great as that of 1913.
It is probable that the dense growth of timber and shrubbery along
the river banks and on the bottom lands had some influence in
impeding the free flow of the river and raising flood levels; and the
existing "standing timber", or forests, may have had some further .
influence in retarding the run-off toward the stream. If these two
conditions are supposed to have balanced, then it would seem that
the run-off and stream discharge of the flood of 1805 may have been
even larger in the vicinity of Hamilton than in the flood of 1913.

The recurrence of great floods in all streams can be surely ex-
pected, and the subject of the report of the Committee is the remedies
to be sought to prevent future disasters from this source of danger.

The writer is in accord with the views expressed by Col. Townsend
in a paperf read at St. Louis, Mo., in April, 1913, on the limited
effect of storage reservoirs at head-waters on floods in the Ohio and
Mississippi Rivers at Cairo, owing to the relatively small drainage
area which such reservoirs can successfully control; and, as has often
been stated, if such reservoirs should happen to be full, coincident
with a great rainfall and run-off — which is a reasonable supposition
during the latter part of the winter — it is difficult to conceive that they
have any beneficial influence on the stream flow below, with the whole
of the run-off from the controlled water-shed flowing over the spill-
ways and into the discharge channels below the dams. The storage
of great volumes of water from the higher portions of a water-shed
simply for flood control can scarcely be looked on with favor. The
use of the stored water for power, for regulation of stream flow, for
irrigation, or for public or industrial water supply, would be sougM
and probably obtained after the construction of the reservoirs, if

* Mr. James T. McBrlde, 1831.

t "Flood Control of the Mississippi River," National Drainage Congress.



DISCUSSION OX FLOODS AND FLOOD PREVENTION 1339

it had not been made a feature of the original enterprise. Unless Mr.
the reservoirs were kept empty before a period of great or long- ' '
continued precipitation on the water-shed, they would fail to con-
serve and restrain the run-off for which they were planned; and, if
kept empty in anticipation of heavy downpours, they would be useless
for any other purpose than flood control.

The method pursued in Europe — to allow a certain depth at the
top of the reservoir for flood control — is practicable, but, in all such
instances, the water stored below the flood-plain is applied to some
utilitarian purpose — water supply, power, etc. The writer does not
recall any investigations showing the control of flood flow below the
resf;rvoirs accomplished by this method.

The considerable number of great reservoirs in Germany and
France (as far as the writer is aware) have not been constructed only
to prevent floods; they have been created for other and more sordid
objects. Neither have any of the great reservoirs in India and the
United States been built with flood control as the only object in view.

Concerning the influence of forests and reforestation on run-off
and stream flow, during periods of heavy or continuous precipitation,
the flood of March, 1805, in the Miami River, at Hamilton, is probably
as great as any on record for that stream. At that date, the Miami
Valley was largely a wilderness, with "standing timber" everywhere
on the drainage area, except in the small clearings of the pioneers,
and, therefore, one of two propositions must be accepted: either the
rainfall exceeded that recorded for March 23d to 26th, 1913, or the
forests had small or no retarding effect on the run-off.

No record of the rainfall for the 1805 flood is obtainable, and prob-
ably there was none, but the time of year and the height of the flood



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