American Society of Civil Engineers.

Transactions of the American Society of Civil Engineers (Volume 81) online

. (page 113 of 167)
Online LibraryAmerican Society of Civil EngineersTransactions of the American Society of Civil Engineers (Volume 81) → online text (page 113 of 167)
Font size
QR-code for this ebook


Leighton lays particular stress on the necessity of engineers — and par-
ticvilarly of this great National Society of Civil Engineers — influencing
legislation. The only way such results can be obtained is by united
action. It became necessary, therefore, for the Committee to seek
some common ground on which its members could agree. It was the
realization of the necessity of adjusting divergent views, if results of
value were to be obtained, not the shirking of duty, which led the Com-
mittee to make the safe and conservative report which Mr. Leighton
criticizes.

Others criticize the report because it does not discuss the subject
in sufficient detail. This phase of the subject was considered by the
Committee, and it was found that the territory is so vast, the problems
arising in various sections of the country so different, that either
general principles, alone, could be enunciated, or a treatise of inter-
minable length, based on incomplete data, would have resulted. A

* St. Louis, Mo.



1304 DISCUSSION ON FLOODS AND FLOOD PREVENTION

brief report, therefore, was agreed upon, leaving to the members the
privilege of elaborating, in the discussion, such details as they con-
sidered advisable.

The science of river hydraulics is not in such a nebulous condition
as Mr. Eakin appears to think, nor does the river engineer have to be
guided solely by the classic work of Humphreys and Abbot. Although,
possibly, American engineers have not investigated sufficiently the
laws governing the flow of rivers, those of Europe have given the sub-
ject profound study. The researches of Fargue on the Loire, Girardon
on the Rhone, Liliavski on the Dnieper, Hagen, Schlichting, and
Jasmund on the rivers of Germany, and others, have revolutionized
the science in recent years. Moreover, the Committee was not
appointed to write a treatise on river hydraulics, and could assume
that the rudimentary laws governing the flow of water in rivers were
known to members of the American Society of Civil Engineers. It
is evident from the discussion, however, that many do not realize suf-
ficiently the differences between the laws governing the flow of water
in pipes, sewers, and other channels having an immovable bed, and
those which govern the flow in a stream having a bed which fills or
scours with changes in velocity. Van Ornum's "Treatise on the
Regulation of Rivers" and the second edition of Thomas and Watt's
'^Improvement of Rivers" throw considerable light on the subject,
and are more suitable sources from which to seek information than a
report on Flood Prevention.

In the minority report, a similar assumption is made. Although
the majority of the Committee states that the physical data are lack-
ing on many streams to enable them to solve the problem of flood
control properly, they are not prepared to admit that "extensive
studies are needed regarding the physical and physiographic laws
affecting stream loads, rate of transportation and deposition and the
variation of these factors with different conditions" before they can
solve the problem if the physical data are supplied.

It is so self-evident that, at such times as the ground is frozen and
trees are without foliage, these conditions prevent the utilization of
reforestation or ground storage, that there is no necessity of making
such a statement in a report. The point the majority of the Com-
mittee makes is that, if floods occur under such conditions, there is
no need of discussing the effects of reforestation or ground storage.
It would be just as pertinent to investigate the porosity of the soil
under an asphalt pavement when designing a sewer to carry the water
which flows over its surface.

It is the writer's opinion that all investigations of the absorptive
powers of different varieties of vegetation and the percolation through
different kinds of soils are more valuable for studying problems of
irrigation and drainage than those of flood control. Though it is con-



DISCUSSION OjST FLOODS AND FLOOD PREVENTION 1305

sidered perfectly feasible to measure these elements within a limited Mr.
area and for a single river, the writer agrees with Gen. Chittenden
that a determination for one situation, or season, or stream, would
never apply reliably to any other. Moreover, to determine absorption
of soils, it is necessary first to measure the run-oil. When the discharge
of a stream is determined, it is of no particular value to the problem
of flood control whether the remainder of the rainfall has disappeared
by evaporation or soil absorption.

The writer has recently investigated floods in Kansas, and they
afford a pertinent illustration of this principle. During the summer
the soil of Kansas provides a reservoir of enormous capacity, having a
power of absorption which has been approximately measured by the
Geological Survey. When the soil is prepared to receive it, a heavy
rainfall will be accompanied by an exceptionally small run-off, but
such conditions are of no value in determining flood prevention, as
violent floods do not then occur. The floods in Kansas arise either
from storms in February or March, when the ground is frozen and
cannot absorb moisture, or in summer from a second storm which
sweeps over the country within a few days after the reservoir capacity
has been exhausted by a preceding rain. The run-off during ordinary
conditions does not enter into the problem.

The majority report emphasizes the fact that reservoirs cannot be
utilized simultaneously to reduce floods, to regulate the low-water dis-
charge, and to increase the water-power that can be developed. The
minority report seeks to minimize the effect of this statement.

There have been constructed at the head-waters of the Mississippi
River a series of reservoirs primarily to increase its low-water flow.
The practical manipulation of these reservoirs forcibly illustrates the
necessity of the remarks in the majority report. Those who have
meadows below the reservoirs demand that the flow be regulated so as
not to interfere with their hay crop, those who raft logs want sufficient
current to assist their business, and those who control water-power
want a constant flow; in times of floods, those living above the dams
are insistent that the gates be opened so as to reduce gauge heights on
the upper river, and those below demand that the gates be closed to
protect their property from overflow.

The statement that levees increase the reservoir capacity of the
river channel appears to require further explanation. The construc-
tion of levees has increased flood heights on the Mississippi River
between Cairo and New Orleans from 6 to 10 ft., and, as the levees are
several miles apart, there is an enormous increase in the channel
capacity during floods in this distance of 1 000 miles. As an illustra-
tion, the channel capacity above the overflow stage is given and com-
pared with that of the Roosevelt Dam, but, as Gen. Chittenden states,
the channel capacity of a river is by no means comparable in effect



1306 DISCUSSION ON FLOODS AND FLOOD PREVENTION

with that of a reservoir. The slope of the river is an important factor
in the problem. The greater the slope the less being the influence of
the channel capacity on flood heights; but, under favorable conditions,
its influence is very large. Notwithstanding the inflow of tributaries,
the maximum discharge of the Mississippi River at Vicksburg rarely
equals that at Cairo, nor at New Orleans that below Red River
Landing.

The straightening of a river has been a subject of discussion by
European engineers for many years. Prior to 1890, German engineers
generally adopted the idea that, in improving rivers for navigation,
the channel should be given a uniform width, bends should be
eliminated, or at least be given as gentle a curvature as practicable,
and the river forced to a uniform slope, the natural gentle slope in
pools in some cases being destroyed by submerged dikes extending out
from the concave banks. The improvement of the Rhine, cited by
Mr. Grunsky, and that of the Danube, cited by Gen. Chittenden, are
examples of this type of improvement. It was also adopted by the
Missouri River Commission for that portion of the Missouri River
between Jefferson City and the Gasconade.

Difficulties, however, were experienced with this method of improve-
ment. No matter how much care was exercised, the slopes through
the improved reach could not be maintained as designed. At the
upper portion, the water surface was gradually lowered, and a bar as
invariably formed below it; an improvement in navigation was created
through the reach, but the channel, both above and below, had less
depth than existed formerly.

In a paper presented to the International Navigation Congress of
1894, on the "Improvement of the Rhone", M. Girardon called atten-
tion to these difficulties, citing as an example the portion of the
Rhone called the Canal de Miribel.

He states :*

"The works were carried out according to this programme and
finished in 1857; the resulting improvement was very evident and the
navigation, in place of the continual uncertainty in which this pas-
sage left it, found in the canal of Miribel a channel easy to follow and
of sufficient depth at any time of year. For several years this improve-
ment appeared to be the only result of the works and nothing indicated
that they could have any inconvenient consequences. Nevertheless
the bottom of the canal was attacked; lower measurements began to be
registered at low water than before the works were executed and these
got lower and lower, while at the exit they marked higher and higher;
then the foundation of the works, which had been made at low water-
level, appeared in the upper portion of the canal and was even un-
covered at the mean summer level of the water, while below the same
water-level the tow-path was submerged and became useless throughout

* Official Translation of the Congress, pp. 27 to 29.



DISCUSSION ON FLOODS AND FLOOD PEEVENTION 1307

the greater part of the year. It became necessary to improve this Mr.
situation which might at any time become very serious. The tow- Townsend.
path was first raised over half the length, that is the part submerged;
then to arrest the movement it was decided to lower the dividing dike
and to cut do-mi the dam of Thil as low as possible, in order to allow
the greatest possible volume of water to find its way through the
false branches, not only in floods but also at the mean water-level. It
was supposed that by this means the main branch would be relieved
and that by decreasing the volume of water which crossed it its scour-
ing action would cease. The result aimed at has been partly realized;
the movement of the profile has become much slower, but has not
entirely ceased; and although the volume of water which passes into
the canal has become notably less, the incline [slope] which will set up
any equilibrium between the resistance of the bottom and the effective
force of the current imder the new conditions of depth has not yet
been attained.

*******

"Thus in spite of the improvement realized, in spite of the
enormously extensive alterations that the river has undergone while
passing between the constant banks, neither regularity in the cross-
section has been obtained, nor constancy in the mean depth, nor uni-
formity in the incline [slope] ; and the bed that has been opened
remains formed as everywhere else of a series of hollows [pools]
separated by ridges [bars], while the profile presents a series of reaches
with a comparatively feeble incline [slope] separated by falls.

''Outside the canal the general incline [slope] of the combined
streams at the entrance to Lyons, at kilometre 5, where the profiles
join, has not sensibly varied; it was and still is 0.81 m. per kilometre,
but its distribution has changed considerably. Throughout the canal,
from kilometre 8 to kilometre 25, it was 0.883 m. ; it is not more than
0.69G m. per kilometre on the other hand above the canal; from kil-
ometre 25 to kilometre 31: it has been raised from 0.75 m. to 0.96 m.,
and below kilometre 8 to kilometre 5 it has been raised from 0.49 m.
to 1.06 m. per kilometre."

The profile. Fig. 6, derived from De Mas' "Rivieres a Courant
Libre", illustrates the condition.

Similar effects have been observed on western rivers of the United
States. In the improvement of the Middle Mississippi below St. Louis
the river was straightened for more than 20 miles. As a result, the
slope was reduced at low water from above 0.6 to 0.25 ft. per mile,
and the low-water surface of the river at the Eads Bridge was lowered
about 3 ft. An excellent channel exists through the improved reach,
but the slope on the Chain of Rocks, above the city, has been increased,
and dredging is required annually immediately below this reach in
order to maintain the required channel depth. Similarly, the Kas-
kaskia cut-off, above Chester, which shortened the river about 6 miles,
has a low-water slope through it of 0.23 ft. per mile, but dredging is
required annually on the crossings above and below.



1308



DISCUSSION ON FLOODS AND FLOOD PREVENTION



Mr. The improvement of the Missouri River reduced perceptibly the

Townsend. low-water plane at Jefferson City, and a cut-off at Camden Bend,
which occurred in 1915, has created a bar 2 miles below it over which
on November 3d, 1916, during an inspection trip made by the writer,
a boat drawing 3i ft. had to be sparred, the gauge at Kansas City
reading 7.8 ft. At the bend above Omaha Mission, about 764 miles
above the mouth, during the June flood of 1916, another cut-off
occurred, and on October 20th the snagboat McPherson, drawing
3 ft., had to be sparred over shoals, both above and below this cut-off,
the Omaha gauge reading 6.4 ft.

On the Arkansas River, a very forcible illustration of the effect of
cut-offs was also afforded during the flood of 1916. In prehistoric
times the Arkansas River, by the caving of its banks, broke into the



River bed, 18i7-
River bed, 1803




Distances, in
Kilometers above ^
rnoutli of Saone



30 25 20 15 10

PROFILES OF RHONE ABOVE LYONS

Fig. 6.



White River, about 10 miles above its mouth, and, until this season,
the low-water discharge of the Arkansas emptied into the Mississippi
through the mouths of the White. The cut-off" between the two rivers
gradually increased in length, and a sharp bend developed. During
the flood of 1916 a cut-off occurred across this neck, resulting in such
a shoaling in other portions of the old channel that at the present time
(November, 1916) the Arkansas River has resumed its old outlet into
the Mississippi and now discharges its low-water flow in a separate
channel from the White River.

On the Red River numerous cut-offs have occurred, with results
equally disastrous. Near Duke's Plantation, below Garland, the cut-off
of 1915 created a bar below it over which at the next low water the
depths of the navigable channel did not exceed 1 ft., and the efforts of
the river to increase its length by caving after these cut-offs occurred



DISCUSSION ON FLOODS AND FLOOD PREVENTION 1309

have been destructive of the levee line which had been constructed Mr.
along the river banks.

It is the raising of the river bed, not the increase of the discharge,
which raises the water surface below cut-offs. The French engineers
have called attention to this, and their views are now generally accepted
in both Germany and Austria.

In his work on the improvement of the Rhine, Mr. Jasmund dis-
cusses the straightening of that river (cited by Mr. Grunsky) and
explains that it 'is due to a previous undue reduction of slope, in
former attempts to improve the river, that renders these cases excep-
tional, and conveys the impression that he disapproves of cut-offs on
other portions of the Rhine.

The straightening of the Danube River in the vicinity of "Vienna,
quoted by Gen. Chittenden, did not improve the navigation of the river
as much as was anticipated. About 3 500 000 cu. m. of material were
scoured out of the cut, and deposited in the river below, raising its
bed, and extensive work has since been required to adjust the low-water
channel to these new conditions. It has even been necessary, in order
to stabilize the bars, to create in the low-water channel new sinuosities
to replace those cut out in the original improvement.

The view that a sedimentary stream seeks to regain its length after
a cut-off did not originate on the Mississippi River, but is a corollary
to views advanced by Guglielmini more than 200 years ago from
observations he then made on the Po. Observations made recently by
the Mississippi River Commission confirm this theory. Guglielmini's
general principle, that there is a relation between discharge, slope, and
the character of the soil, has also been verified by the changes which
have taken place recently in the Atchafalaya and Illinois Rivers. In
both these rivers a change in their discharge created by artificial
means has been accompanied by a marked change in the radius of
curvature of bends. A citation of an unreliable reconnaissance by
Lewis and Clark is not considered sufiicient proof to overcome the over-
whelming evidence that can be cited to prove that rivers do strive to
adjust their length to their discharge and slope.

Gen. Chittenden also takes exception to the distinction made by
the Committee between streams created by glacial action and those
carrying a large quantity of sediment. Although not agreeing with
Mr. Fuller, that there is a necessity for a new variety of engineer,
called by him the geological engineer, the writer believes that all engi-
neers who investigate river j^roblems should have knowledge of
geology. The methods of improvement which are successful with the
gentle slope of rivers created by glacial action have frequently failed
when applied to streams carrying large quantities of sediment. Thus,
on the rivers connecting the Great Lakes a permanent channel of
21 ft. can be dredged, but on the Mississippi a channel dredged to
9 ft. fills annually. The permeable dikes, so successful on the Middle



1310 DISCUSSION ON FLOODS AND FLOOD PREVENTION

Mr. Mississippi, were failures when applied to the Upper Mississippi above
■ Keokuk. On the Illinois River a cut-off could be made with impunity,
but the writer believes it is impossible to improve the Missouri River
permanently unless cut-ofFs are prevented.

In reference to outlets or spillways, the writer does not apprehend
the danger to the channel of the main river from their construction
that some do. He is a firm believer in the idea that rivers have a
tendency to correct man's errors, and that, if outlets are constructed,
a fill will occur in the outlets rather than in the river channel; but, if
the outlet is given such dimensions that it begins to enlarge, there is
imminent danger that the main channel will not only fill but be
abandoned, unless the process is checked. A river exhibits an objec-
tion to serving two masters.
Mr. Morris Knowles,* M. Am. Soc. C. E. (by letter). — In contributing

"' to the closure for the Minority, the writer expresses the conviction
that the character of the discussion presented demonstrates conclusively
that the attempted premature discharge of the Committee, on two
occasions, and before a final report was submitted, was an unfortunate
mistake. It is evident, also, that the discussion has fully justified
the contention of the Minority that assertive statements, with a limited
point of view only, and in the face of present divided opinion on the
subject, will not promote progress or the development of a much
needed comprehensive programme for stream control, but will rather
intensify discord where it is not necessary. The object of the Com-
mittee, in so far as it could not agree on a final pronouncement, ought
to be to promote further investigation and discussion, and not to
attempt to close the door by dogmatic expression of a single point of
view.

It is apparent, at a time when the importance of regulation of
stream flow in its largest sense, which includes flood control as a
part, is engaging the attention of the country and impressing itself
on laymen, that the Society has lost a wonderful opportunity to pro-
mote sound thinking and the development of a programme looking
toward wise legislation. It is plain from the public interest, general
discussion, and proposed laws, that no one type of control is a universal
panacea, or will do for all classes of streams; also, that the opinion
of a single branch of scientific men, not in sympathy with all phases
of stream regulation, will long satisfy the country, for such opinion
will stifle progress and unduly lengthen the period required for reaching
the desired results.

The writer expresses the hope, therefore, that, at some later date,
the Society may take up this important subject again and continue
its consideration until it becomes possible to prepare a report which
will merit the consideration justified by the high standing of the
Society.

• Pittsburgh, Pa.



AMERICAN SOCIETY OF CIVIL ENGINEEES

INSTITUTED 1852



TRANSACTIONS



This Society is not responsible for any statement made or opinion expressed
in its publications.



Paper No. 1401



FINAL REPORT

OF THE SPECIAL COMMITTEE

TO FORMULATE PRINCIPLES AND METHODS

FOR THE VALUATION OF RAILROAD PROPERTY

AND OTHER PUBLIC UTILITIES*



With Discussion by Messrs. J. E. Willoughby, C. E. Grunsky,
Joseph Mayer, and W. R. McCann.



Committee :

Frederic P. Stearns, Chairman,

Charles S. Churchill, Henry E. Riggs,

William G. Raymond, Jonathan P. Snow,

William J. Wilgus,

Leonard Metcalf, Secretary.



Presented to the Annual Meeting, January 17th, 1917.



1312 VALUATION OF PUBLIC UTILITIES



PEEFACE.



In presenting this report to the Members of the American Society
of Civil Engineers, the Committee is fully alive to the fact that the
art of valuation is still in formative condition, as is evidenced by the
conflicting views expressed, or principles enunciated, even by the
higher Courts. That debatable subjects arise frequently, and vpill con-
tinue to do so, is indicated by the record of the Committee's work
incident to the rendering of this report, for in spite of the prior knowl-
edge of its members on this subject, and professional experience in it,
five years have elapsed since their appointment, in which forty-eight
joint meetings have been held, many of them consisting of three ses-
sions, and a voluminous correspondence has been carried on, aggrega-
ting thirteen substantial volumes.

Nevertheless, the fact that nine men of widely different training
and experience, practising in different professional lines and iields,
have been able to come finally to common belief upon most of the
subjects discussed — the principles which should control the valuation
of normal public utility properties — leads the Committee to hope
that this report may be helpful to others, and may serve to clarify this
very involved subject, to the common advantage of public service
corporations and the public served, by aiding in the establishing of
procedure and in the reducing of the uncertainties of valuation and
rating of public utility properties.

Where differences of opinion have developed, the conflicting views
of the Court have been cited, the effect of the application of different
theories indicated, and the course of action most likely to lead to a
fair settlement of debatable questions has been outlined.

The Committee bespeaks a thorough and open-minded study of
the whole report, by the members of the Society interested in the
subject. Only with such a background will its full significance be
apparent. The subject is so involved and many-sided that brevity
and conciseness are not always possible, and that brief statements
may not always be capable of isolation from the context without the
possibility of causing ambiguity; therefore, though the Committee has
prepared an abstract of its conclusions for the convenience of the
readers of the report, it hopes that the members of the Society will
base their conclusions and discussions on the main report, rather
than on the abstract.

The table of contents follows. Thereafter are given, successively,
the abstract, the introduction and other chapters of the report, and
finally a detailed glossary.

October 28th, 191 G.



VALUATION OF PUBLIC UTILITIES 1313

CONTENTS.

PAGE

Abstract of Eeport 1318

Chapter I. — Introduction 1330

Progress Eeport Presented January 21st, 1914 1330



Online LibraryAmerican Society of Civil EngineersTransactions of the American Society of Civil Engineers (Volume 81) → online text (page 113 of 167)