Bulletin
OF THE

Illinois State Laboratory
09

Natural History

Urbana, Illinois, U. S. a.

STEPHEN A. FORBES, Ph.D., hh.D.,
Director

Vol. IX. June, 1913 Article X.

STUDIES ON THE BIOLOGY OF THE
UPPER ILLINOIS RIVER

BY

Stephen A. Forbes and R. E. Richardson, A.M.



ERRATA AND ADDENDA

Page 54, lines 3 and 2 from bottom, and elsewhere in Article III. for Cassia

chainaechrista read Cassia chamaccrista.

Page 62, between lines 4 and 5 from bottom of table insert Erigeron annuus.

Page loi, table, after Croloii glandulosus read var. septentrionalis: and for

Eijuisettim laeinyatum read Eqnisetum bycmale var. inlermedium.
Page 131. line 3, for coerulea read caerulca.

Page 138, last line, for Zi::a read Zizia.

Page 141, line 21 from bottom, dele Diodia teres.

Page l6g. between lines 3 and 4, insert as follows

:

Erigeron annuus (L.) Pers. An interstitial in the liunch-grass association

in the Hanover area.

Page 177, line 5, for casti^'ard read iveslzvard.

Page 209. line 3 from bottom, for copalina read copallina.

Page 210, line 13 from bottom, for Diospyrus read Diospyro'i.

Page 211, line 5, for Foresteria read Foresticra.

Page 256, line 3 of table, for Dr. H. M. Pepoon read H. 5". Pepoon.
Page 278, line 16, the fifth word should be in Roman type.

Page 286, line 6 (second column), page 295, list of secondary species (second
column), and page 353. line 8 from bottom, for hiematis or hiemale read hye-
mnte.

Page 313, line 4 from bottom (first column), for pedicularis read pcdicularia.

Page 315, line 10, second column, for Apoeynum read Apocynum.
Page 323, line 3 from bottom, for Cyperus read Scirpus.

Page 330, line 14, for virginianum read inrginicum.

Page 336. lines 3 and 2 from bottom, for virginicum read virginianum.
Page 337. line 2 from bottom, for philadelphicum read philadelphicns.

Page 339» in first list of invading species, for Rhus hiria read Rhus typhiua.

Page 351. line 4 from bottom, for .verophtic read .verophytic.

Page 355, above line 6 from bottom, insert Scirpus heterochaetus Chase.
Page 356, line 14 from bottom, for Symlocarpus read Symplocarpus.
Page 360, line 14, for Pirus read Pyrus.
Page 362, after line 7, insert Acer saccharinum L.

Page 363, line 2 from bottom, for quadiflorum read quadriflorum.
Page 365, line 14, for Ihapus read thapsus.
Page 369, last line, for Tanecelum read Tanaceium.
Page 417, line i. dele the.

Page 497, line 9 from bottom, for neglible read negligible, and in foot-note, for
Auslall read Anstalt.

Page 498, line 4 from bottom, for Lockport read Chillicothe.

Page 500, line 13 from bottom, after up insert in.

Page 5or, line 2 from bottom, for dissolving read dissolved.

Page 504, line 23, for gryina read gyrina : line 17, for dentata read knickerbockeri.
Page 506, line 11, for vernata read ternala.

Page 507, line 3 from bottom, for Macon read tt'asoi.

Page 513, line 19, for Nepa read Zaitha; line 18, and page 517, line 13 from bot-
tom, page 520, line 12 from bottom, and page 532, line 4, read naid or naids
for naiid or naiids.

Page 517, line 6 from bottom, for pondiveed read pickcrel-iveed.



Page 519. for first sentence of last paragraph read as follows:

We have no exactly comparable chemical data for July; but analyses

for August give percentages of saturation for Morris and Marseilles as follows :

20.4 per cent, at Morris on the nth and 11 per cent, at Marseilles on the 12th;

16.35 P<^r cent, at Morris on the 22d and 23d and 7.4 per cent, at Marseilles on
the 24th and 25th.

Page 521, line 6 from bottom, and page 529, line g, for chrysoleucas read cryso-

leticas.

Page 525, line 22, and page 536, lines 21 and 24, for Ekmann read Ekmnn.
Page 532, line i, for Ancyclus read Ancylus.
Page 551, line 7, for 00 read 572.

Page 615, second line above foot-note, for 106 read 94.

Page 616, line I, for the second Biindeln read Bilndel; line 2, for Biindeln read
Biindcls; line 3, for ausscrn read ausscren; line 6, for sweierlie read sweierlei.

Page 629, line 12, for kciii read kcincn.
Page 634, line 9, for untcrnommcn read untcninntincnen; and in line 14 from

bottom, after ;;/$ insert is fig.

Plate III, Fig. i, after the word mixed in legend insert consocies of the.

Plate IX, Fig. 2, dele the legend and read instead ; Root-system of Tephrosia
virgiiiiana, exposed by blowing of the sand.

Plate X, Fig. 2, dele the legend and read instead ; A blowout almost stabilized

by bunch-grasses, especially Leptoloma cognatum.
Plate XXXIX. for Calainogrostis read Calamagrostis.
Plate LIV. exchange places of cuts, but not the legends.
Plate LXXXV, for 7 read ye.



Article X.

—

Studies on tlic Biology of the Upper Illinois River.

By Stephen A. Forbes and R. E. Richardson.

The Illinois River is peculiarly characteristic of the State of Illi-

nois, and, next to the prairies, was its leading natural feature. The
level richness of the central plateau of the state is reflected in the

turbid waters and the broad sluggish current of the stream; and
its wide bottom-lands, originally covered with huge trees, completely

flooded when the river is highest, and holding many marshes and

shallow lakes at its lowest stages, are a relic of the time, not so very

far remote, when the limpid waters of the Great Lakes rolled down
its valley in a mighty flood on their course to the southern gulf. It

was not an accident that this river was the first great artery of

transportation into and through the state, or that the first colonial

settlement and the first fortified post in Illinois were established on
its banks. After the railroads had deprived it of its commerce it

was discredited and neglected for many years, and the second city

in the country and the second city of the state have long used it as

a mere convenience for the discharge of their organic wastes.

These are temporary conditions, however, and the time seems

now at hand when the people of Illinois will learn to appreciate and

develop this great gift of nature in the various directions in which

it may be made to serve their interests and their pleasures. Its fre-

quently beautiful and occasionally picturesque scenery is attracting

more attention every year; and when, as is sure to happen in due

time, a superior highway follows its course between Chicago and

St. Louis; when the attractive building sites on its banks are re-

lieved, as they now might generally be, from the midsummer plague

of mosquitoes; when its most interesting situations are converted

into public parks, and its fisheries are protected and enriched by

means of state reservations for the breeding and feeding of fishes

;

and when, as must eventually come to pass, it becomes once more an

indispensable central link in a principal line of traffic between the

Great Lakes and the Gulf,—it will take for all time, for the state

at large, the place which Lake Michigan now holds for our greatest

city.

The senior author of this report began work, as a biologist, on

Illinois River problems, some thirty-si.x years ago; and the junior

author has virtually lived on the river for purposes of investigation

during the last four years. The Natural History Survey of the state



482

has published in the meantime more than twenty-five hundred pages

of contributions to its biology ; and it is now rounding this work
to a close, and bringing its results to bear, in practical ways, upon
the economic problems most pressing and important at the present

time. The paper here presented is intended as a preliminary sum-
mary only of the principal conclusions, scientific and economic, to

be drawn from our studies of the last few years, and it is to be fol-

lowed presently by a series of special papers on the various divisions

of the investigation.

Acknowledgments

Our grateful acknowledgments are due to the U. S. Bureau of

Fisheries for financial assistance in carrying out a fairly adequate

program of field work in 191 1 and 1912; to the Illinois State Fish

Commission for opportunities afforded us to obtain the plankton of

the Illinois, Mississippi, and Ohio rivers on long steamer trips which

we could not otherwise have made ; to the Water Survey of the

State, the director of which. Dr. Edward Bartow, has taken virtual

charge of the chemical work here reported, and has provided, from
his stafT, experienced analysts who have made all our determinations

of gases from the waters and from the river sediments ; and to the

directors of the Missouri Botanical Garden, in St. Louis, Dr. Wm.
Trelease, succeeded by Dr. George T. Moore, who have placed the

library, collections, and laboratory facilities of the garden at our

disposal, and the latter of whom has given us also his personal as-

sistance in determining the alg£e of our river collections.

Objects of the Investigation

The Illinois River work of the Natural History Survey, pursued

at irregular intervals since 1877, became virtually continuous at

Havana for five years, from April, 1894, to March, 1899, after which

it seemed expedient, first to diminish, and in 1903 to suspend, field

operations in order that our more important scientific results might

be organized, reported, and published. This end being largely ac-

complished by voluminous papers printed in volumes IV, V, VI,

and VIII of the Bulletin of the State Laboratory of Natural History,

and by the publication also, in 1908, of an elaborate report on the

fishes of the state, active field work on the river problems was re-

sumed in July, 1909.

The opening of the Chicago Drainage Canal in 1900 was a revo-

lutionar}' event in the biological history of the river; and as the



483

most important period of our earlier work was that immediately pre-

ceding this event, an examination of its consequences to the general
system of aquatic plant and animal life was an important part of
our object in recommencing systematic study. As the Illinois is a
rather peculiar member of the great Mississippi River system, it was
also much to be desired that comparative studies should be made on
the life of the more closely related companion streams; and as the

Illinois is economically one of the most productive rivers in the
United States, it was evidently time to study the subject of the con-
servation and possible increase of its values in the light of the knowl-
edge we had gained, and intended to gain, of its physical, chemical,
and biological conditions and requirements.

The economic problem seemed especially urgent because of the

great changes in progress at the time in the environment of the river,

and the still greater changes impending, which were certain to affect

greatly and permanently its value for the purposes which it had
previously served. Reclamation projects, for the protection, drain-

age, and cultivation of its bottom-lands ; manufacturing projects,

threatening various contaminations of its waters; canalization proj-

ect ; and projects for the control of its flow in the interests of

transportation, were all being earnestly agitated, and some of them
were in course of active development. It is true that these changes
are both inevitable and desirable, in view of all the interests involved;

but it becomes all the more imperative to learn as promptly as possible

what their effects have been and are likely to be, in order that prac-

tical correctives may be applied where necessary, to the end that a

modus xk'cndi may be found which will take all these interests into

full account, and make sure that nothmg is needlessly sacrificed in

the course of the use and development of the stream.

The reports of the work of the earlier period were largely on the

minute plant and animal life of the stream—its so-called plankton

—

which forms a considerable part of the food of many kinds of fishes

and nearly all the food of the young of almost every kind; and tlie

plankton product of the waters of the Illinois under the new condi-

tions, as compared with those prevailing before the opening of the

sanitary canal, was one of the first topics to commend itself to us •

for careful study. Involved in this subject of food production for

fislies, river mussels, and other useful aquatic animals, was the
economic effect of a great increase in the flow of the stream, the

rise in its levels, and the consequent expansion and longer contmuance
of its overflows, which there was some reason to suppose might so
increase the food supply and enlarge the breeding and feeding grounds



484

of fishes as to increase the fisheries products of the stream. It was
also a matter of interest and importance to learn the effects, both

direct and indirect, of the increased inflow of sewage by way of the

sanitary canal and the Des Plaines, upon the fishes and moUusks of

the Illinois—an inquiry calling for chemical examinations of the

waters of the stream and systematic collections from it at various

points on its course, under various conditions, and at different times

of the year.

Character and Chronology of Field Operations

The work planned upon these lines has taken three directions

:

the first year was given mainly to a study of the plankton of the river

and of the principal bottom-land lakes, made on the same grounds
and by the same methods and equipment as those of the period from
1894-1899; the second year was devoted especially to chemical de-

terminations of the gases of the waters and of the bottom sediments

of the upper river, from its origin to Chillicothe, and to parallel

collections of the minuter plankton—the so-called microplankton

—

of the stream made at the same times and places as the chemical

studies ; and in the third year, similar chemical and biological de-

terminations were made, with principal attention, however, to fishes

and mussels and to the other plant and animal life of the bottom and
the shores.

Advantage has also been taken of opportunities given us by the

State Fish Commission to collect the plankton of the Mississippi and
Ohio rivers for comparison with that of the Illinois, and especially

to study the effect of protracted drouth and continuous low water

on plankton production in the streams themselves. Much time was
given during the spring seasons of 1910 and 191 1 to field studies of

the habits of spawning fishes and the times and places where their

eggs were laid, and to the fate of the eggs and the rate of growth
of the fry. These observations were intended especially to give us

a better knowledge of the proper limits of a closed season for the

protection of the more valuable fishes, and to show us also what
measures are necessary to keep the numbers of the young up to the

limits set by the available food supply.*

The collection of materials for a comparative study of the plank-

ton of our principal rivers was actually begun in 1902, when virtually

continuous collections were made from the steamer "Illinois" of the

*For a summary of results, see Bull. 111. State Lab. Nat. Hisl., Vol. IX,
articles VII and VIII, March, 1913. ;



485

State Fish Commission, beginning at Montezuma, on the lower Illi-

nois River, going thence to Grafton, at its mouth, from Grafton up

the Mississippi to Quincy, down that stream to St. Louis, from St.

Louis back to Grafton, and thence up the Illinois to Pekin. The
systematic plankton collections of this trip were the first ever made
on the Mississippi River. Additional collections were obtained in

1902, by the use of the station launch, from Pekin to Peoria Nar-
rows, and in August, 1903, from Wesley, below Peoria, to Henry,
thirty-three miles above. The next long trip was made June 8-17,

1910, again on the steamer "Illinois," from Keokuk, Iowa, to Quincy
and St. Louis, and thence up the Mississippi and the Illinois to La
Salle, with a return to Havana; and additional materials for a study

of the plankton were obtained by means of numerous collections in

Peoria Lake, July 19-22 of this year. The final trip of the series

was made with the "Illinois" July 25 to August 6, from Havana
down the Illinois and the Mississippi to Cairo, and thence up the

Ohio to Paducah, Ky., where we left the steamer, to rejoin it at

St. Louis for continuous collections up the Mississippi and the Illi-

nois to La Salle, and back to Havana.

In 191 1, chemical determinations and biological collections for

an analysis of seasonal conditions on the upper Illinois and in re-

lated waters, were begun July 18 and repeated at frequent intervals

until the 13th of December. Similar trips were made in February
and March, 1912, for a study of winter conditions; and in July,

1912, an elaborate series of oxygen determinations was made for

the entire length of the river. August 21 to October 12, two such

series were obtained for the upper Illinois ; and in November two
more, for the whole stream, with comparative tests for the Missis-

sippi, below and above the mouth of the Illinois. The situations

thus brought more or less closely into comparison were the sanitary

canal at Lockport, the Des Plaines River at the same place and at

its mouth (Dresden Heights), the Kankakee just above its mouth,
and the Illinois River at Dresden Heights, Morris, Marseilles (both

above and below the dam which crosses the river there), Ottawa,
Starved Rock, Peru, Hennepin, and Chillicothe. The distances of

these points from the mouth of the Chicago River are approximately

as follows, in miles: Lockport, 35; Dresden Heights, 53; Morris,

62; Marseilles, 80; Ottawa, 86; Starved Rock, 95; Peru, 102;
Hennepin, 116; and Chillicothe, 145, ninety-two miles of this last-

mentioned distance being on the Illinois River itself.

In 191 1, low-water midsummer conditions were shown by studies

pursued between July 15 and August 29, during which time three



486

successive trips were made, the first from Lake Michigan and Lock-

port to ChilHcothe, and the other two from Dresden Heights to the

last-named point. Early autumnal conditions were studied from

Lockport to ChilHcothe at various dates in September; late autumnal

conditions betw';en the same points, November i-io; and winter

conditions at Mcrrjs and Marseilles, November 30 to December 3.

On this last visit the collection of fishes from the more con-

taminated parts of the stream was first attempted by means of seines.

Observations on fishes had, however, been made at various points

from the beginning of operations in July.

From the i6th to the 28th of February, 1912, efforts were per-

sistently repeated at Morris to obtain fishes from the river by the

use of seines and fyke-nets, and by the explosion of dynamite. Oxy-
gen determinations were secured at this time from all the usual

points between Lockport and ChilHcothe, as well as from the Kan-
kakee above Dresden Heights; and the following month (March 18-

28) a full series of such determinations was made the whole length

of the river from Morris to Grafton, from the Des Plaines and the

sanitary canal at Lockport, and from the Mississippi above the mouth
of the Illinois. It was the object of this series to give us the data

for a comparison of extreme seasonal conditions throughout the

course of the stream.

Lack of funds prevented a resumption of our biological river

work in the spring of 1912; but the new appropriations of the

Natural History Survey, available July i, fortified by an allowance

from the U. S. Bureau of Fisheries, enabled us to resume the collec-

tion of chemical and biological data August i, and to continue it

without intermission until October 25.

In this time the chemistry and biology of the situation was stud-

ied, on two successive trips, at each point from Lockport to ChilH-

cothe, collections of plants and animals being obtained with dip-nets,

large and small seines, trammel-nets, set-nets, dredges, and the mussel-

bar, and by the explosion of half-pound cartridges of dynamite, and

oxygen ratios being determined for each place and time at which the

biological data were obtained.

Finally, in March, 19 13, samples of the bottom sediments were

collected from all the five Illinois River dams, and from some other

points in the main channel, for physical and chemical examination,

with a view to ascertaining the condition of the river bottom when
the river water has been for some months at or near the freezing

point.



487

Importance of the Plankton

The economic importance of the plankton is largely in the pre-

dominance of these minute animals and plants in the food of the

young of our most important fishes,—a predominance which may
be expressed, without serious exaggeration, in the aphorism : no
plankton, no fish. Furthermore, adults of many useful species, the

crappies and the sunfishes, for example, often cram their stomachs

with plankton organisms when these are especially abundant, as in

spring. The youngest fishes and adults differ, however, as a rule,

in their mode of obtaining this kind of food, the latter straining it

out of the water by means of their gill-rakers and the former cap-

turing the minute animals one by one, as full-grown predaceous fishes

capture their larger prey. There is, indeed, an important exception

to be made to the foregoing too sweeping statement. The young of

the sucker family seem to take their earliest food much as do the

adults—by sucking it up from the bottom—and while many plankton

organisms are caught by them in this way, these are largely forms

which commonly live on or near the bottom, the free-swimming spe-

cies (Dapluiia, Cyclops, and the like) being commonly scarce in the

food of this family. The young of some other species also feed

habitually near the bottom, so that the bottom-loving plankton or-

ganisms are represented in their food in disproportionate numbers as

compared with the average product of the plankton net. Neverthe-

less, conditions which bring about an abundance of true-floating or

free-swimming plankton, have, generally speaking, a like effect on
the more significant part of the minute bottom-life of our waters

generally, and the yield of the collector's net is thus a fairly relia-

ble index to the food supply of young fishes, of whatever habit. It

is true that these, as a rule, make little use of the plants of the

plankton as compared with its animals, and that the numbers of the

two often do not vary together; but if we remember that the plank-

ton animals themselves feed largely on microscopic plants, we shall

see that the latter are indirectly useful to fishes, even when not di-

rectly so.

Changes in River Levels

It follows from the foregoing discussion that one of the im-

portant points to be determined in our earlier operations of 1909
and 1910 was the effect on the plankton content of the Illinois River
and its connected waters traceable to the opening of the Chicago



488

Drainage Canal, and to the increase in the volume of the stream and

in the extent and continuance of its overflow consequent upon that

event.

Something of the magnitude of this increase may be inferred from

a comparison of the river-gage readings at Havana or below Cop-

peras Creek dam for two ten-year periods preceding the opening of

the canal (on January 17, 1900) and the ten years immediately fol-

lowing. The period from 1880- 1889 inclusive was characterized by

relatively high water, with an average of 7.4 feet above the low-

water base-line of 1879; the second, from 1890-1899, was a low-

water period, with an average gage reading of 6.32 feet ; and the

third or last period of ten years, from 1900-1909, was a maximum
period, with an average of 9.72 feet. Taking these last two periods

into comparison, separated, as they are, by the opening of the sani-

tary canal, we find a difi^erence of 3.4 feet of average level, attrib-

utable in great part to the access of canal waters. There was, how-
ever, an apparent difference between these two periods in the rainfall

of the upper Illinois basin amounting to 1.9 inches, which may be

held to account for a part of the average high water of the later one.

The River Plankton

Our Havana plankton collections were made in series, at suffi-

ciently frequent intervals between August 30, 1909, and August 29,

1910, from three localities—the Illinois River, Thompson's Lake,

and Quiver Lake. Forty collections were made in this period from

the river, forty from Quiver Lake, and thirty-nine from Thompson's,

distributed as follows by months: 1909—August, i collection; Sep-

tember, 4 collections; October, 4; November, 5; December, 2. 1910

—January, i ; February, i ; March, 2 ; April, 4 ; May, 4 ;
June, 3

;

July, 5 ; August, 4. In December only one collection was made from

Thompson's Lake.

The average plankton product of the Illinois River for each

month of this year (August, 1909, to August, 1910), stated in cubic

centimeters of plankton to one cubic meter of water,* is shown in

the following table, together with corresponding monthly averages

for the three years from September, 1895, to August, 1898, inclusive.

*Equivalent, of course, to parts per million by volume.



489

Ii.i,iNOis RrvER Plankton, Main Stream at Havana, III., 189S-'98 and
1909-'10. Given in Cubic Centimeters of Plankton to

One Cubic Meter of Water



490

Monthly Means of Gage Readings

Illinois River, Havana



491

1909, to September, 1910, than in any year of our collection period

preceding the opening of the drainage canal. As the river contains,

generally speaking, a mixture of contributions from all its tributary

waters, the quantities of its plankton, particularly during the spring

months when these waters communicate with it most freely, are the

best obtainable index to plankton production in the whole system of

streams and lakes whose surplus water it carries away. Neverthe-

less, a comparative study of conditions in two highly typical bottom-

land lakes, so made as to show the effects in them of a change to

the new and higher water-level, will have its special interest, partic-

ularly as it is in these bottom-land backwaters that most of the

fish fry are hatched, and spend, as a rule, the first weeks of their

existence.

The Lake Plankton

Thompson's Lake.—Thompson's Lake is a typical, permanent bot-

tom-land lake, continuously connected with the river at all stages of

water. In the higher stages the land between it and the main stream

is completely overflowed ; at medium stages the river water enters

at its upper end and flows out from its lower ; but at the lowest

levels the lake is connected with the stream only by a narrow creek-

like outlet at its upper end. At six feet above "low water" it covers

nearly 3000 acres ; and at a river level of nine feet its area is about

4300 acres.*

As will be seen from the following table, the plankton series of

Thompson's Lake for 1909-10 does not closely resemble any one of

the series of the earlier years, although the latter part of it, from
February to August, 19 10, is quite similar to the corresponding part

of the record for 1897-98.

*Tabulation of Areas of Thompson Lake for the Various Water Elevations.

Report of the Submerged and Shore Lands Legislative Investigating Committee
(Forty-seventh General Assembly), Vol. I, p. i7i.



492

PLANKTON OF THOMPSON'S LaKE, 1894-99 AND 1909-10

Cubic Centimeters to the Cubic Meter



493

mer and in fall, except when occasional floods would sweep it clean

for a time; but since the drainage canal was opened its character is

completely changed, and there is now but little vegetable growth to

be seen in it at any time of the year. It is also, of course, now con-

siderably larger and much more freely connected with the river than
before, and the lowlands separating it from the stream are much
longer under water.

Plankton of Quiver Lake, 1895-99 and 1909-10

Cubic Centimeters to the Cubic Meter



494

895 & '96 to 1897 & '98

^909 & '10

River

2.16
5.07

Quiver Lake

1.93
6.13

Thompson's Lake

7.80
7.77

In the three full years of the earlier period whose data are used

in this discussion, the plankton of Quiver Lake water was lowest,

that of the river was but little higher, and that of Thompson's Lake

was three and a half times the latter. In 1909-10 the yield of the

river was lowest, that of Quiver Lake was 21 per cent, larger, and

Thompson's Lake yielded 27 per cent, more than Quiver, the change

being due to a great increase in the river yield and a still greater

increase in that of Quiver Lake, while the yield of Thompson's Lake
remained substantially unchanged.

If to these facts concerning the increase, in recent years, in the

percentage of plankton contained in the waters of the Illinois, we add

those concerning an increase in the average volume and area of the

waters themselves, we shall see that their total plankton product must

have been many times multiplied, and that the fisheries of the stream

should feel the effects of this greater abundance of this important

element of fish food
;
provided, it must be added, that the plankton

supply is really at any time a limiting element in the production of

fishes, such that we may amend the aphorism given on another page,

to the form : "The more plankton, the more fish." It will, however,

be a long time, in the writers' judgment, before the whole economy

of fish production in our streams is so thoroughly understood that

such a statement will be warranted. At present we can only say that

there was produced in the waters and backwaters of the Illinois, in

1909-1910, an available and accessible amount of fish food sufficient

for a much greater population of fishes than the stream had pre-

viously supported, and that if no such population is maintained, the

reasons for the fact must be sought in some other direction.

Causes of an Increased Plankton

No change has recently occurred in the Illinois River system, or

in the basin of the Illinois, to account for the increased productivity

of its waters except the one already repeatedly referred to—the open-

ing of the sanitary canal connecting the Illinois and the Chicago

rivers at the beginning of 1900. The efifects of this occurrence on

the plant and animal products of the stream may conceivably have

been produced in one or more of these three principal methods: (a)



495

by a mere increase of the waters themselves, which, in so sluggish

a stream as the Illinois, with bottom-lands so extensive and so widely

overflowed by so small a rise of the river levels, will take effect

mainly in great expansions of shallow water, long continued or per-

manently maintained, with muddy bottoms and more or less weedy
shores—situations quite capable of producing a relatively enormous
plankton as well as an abundant supply of shore and bottom animals

and plants; {b) by the addition of increased quantities of organic

matter to the contents of the stream in the form of a larger inflow

of sewage from Chicago and its suburbs, in condition to increase the

plankton by increasing the supply of food available to the minute
organisms which compose it; and (c) by the addition to the plank-

ton of the river, of that of Lake Michigan brought down in the

waters of the canal.

The efiicacy of the first of these conditions is undoubted, as

has been already shown, and that of the second is, generally speak-

ing, quite possible. The importance of an abundance of organic

matter in the water as a means of producing a rich plankton is, in

fact, so well known that growers of pond fishes in Europe delib-

erately manure their ponds to increase the supply of food for their

fish ; and there is considerable evidence, also, that the plankton of

the Elbe is largely increased by the sewage of Hamburg and Altona
poured directly into that stream. Whether Chicago sewage has a

like effect in the Illinois, and whether, if it has, that effect may not

have disappeared before the waters of the stream have reached Ha-
vana, are problems which will be taken up in a later paper. The
supposition that the waters of the canal may bring to the Illinois a

richer plankton than that of the river itself is negatived at once by
the fact that Lake Michigan water is relatively poor in microscopic

life, and hence must dilute the river plankton instead of increasing

it ; and by the further fact that most of the characteristic minute
organisms of the lake have died out in the river before they reach

Havana.*

ILLINOIS RIVER WORK OF 1911 AND 1912

The Illinois River, it will be remembered, is formed by a union,

near Dresden Heights, of the uncontaminated Kankakee and the

heavily polluted Des Plaines. The waters of these streams flow down

*A partial exception to tliis statement is found in the survival in the river of
the lake diatom Tahellaria fiocculosn. its increase after it passes the Morris-Mar-
seilles ordeal, and its immense multiplication in Peoria I^ke. This species was
not found in the Illinois licfore the opening of the drainage canal.



496

the larger river, the Des Plaines water on the north side and that

of the Kankakee on the south, and are not completely mingled until

the first dam is reached, at Marseilles, twenty-six miles below. They
are less distinct, however, than they would be if it were not for an
unfinished dam at Dresden Heights, which acts as a wing-dam to

concentrate and hasten the current of the Des Plaines, throwing it

with some force towards the other side of the Illinois, thus arti-

ficially mixing, to some extent, the waters of the Kankakee and the

Des Plaines at their junction. These continue sufficiently separate,

however, as far down as Morris, nine miles below the junction, to

make a notable difference in contamination between the two sides

of the stream.

The effect of the dam at Marseilles is to check the current above
sufficiently to permit a considerable precipitation of suspended mat-
ter, which accumulates there in a deep bed of more or less putrid

sludge. In going over the dam the water is thoroughly mixed and
aerated, and the softer masses suspended in it are pulverized, and
thus made ready for more rapid decomposition.

Between Dresden Heights and Morris the waters of the Illinois

are slightly diluted by contributions from the Au Sable on the north
and Mazon Creek on the south. At Ottawa, the Fox River comes
in from the north—a stream a hundred and fifty miles long with an

estimated low-water discharge of about two hundred and forty cubic

feet per second.* On the southern side is the Vermilion, ninety

miles long, emptying opposite La Salle.

These are the only tributaries of the upper river of sufficient

importance to be noticed as influencing sensibly chemical or biolog-

ical conditions in the main stream. A cluster of bottom-land lakes

of some importance is found above Hennepin, and Senachewine Lake
has its outlet into the river between that town and Henry. .At the

latter point is a dam which repeats, to some extent, the effects of

the upper dam, at Marseilles. Chillicothe, which was the lower limit

of most of our operations, is at the upper end of that expansion of

the Illinois known as Peoria Lake.

The Microplankton, Summer of 191 i

Three successive rounds were made in the summer of 191 1 to

the selected list of stations between Dresden Heights and Chillicothe,

by a chemist (Mr. Charles H. Spaulding) and a biologist (the junior

*Chemical and Biological Survey of the Waters of Illinois, Report for 1911,

p. 162.



497

author) working conjointly. The first trip vvas made July i8 to

August 4; the second, August 10-17; and the third, August 21-29.

The weather of July and August, 191 1, was imusually dry and
hot, with the river continuously at very low level. A rain of about
a quarter of an inch fell July 20, in the upper Illinois valley, but
this had no perceptible effect on the river. Upwards of an inch of

rainfall August 10, followed by a rise of about six inches in the

Kankakee, also brought the Illinois up in the Morris-Marseilles sec-

tion, and the August stage of water was throughout a little higher
than that of July.

In collecting from the waters of the flowing stream, all samples
were taken within eighteen inches of the surface, by means of a liter-

bottle opening and closing mechanically. On the return from the

field the contents of each liter flask were thoroughly shaken together

and 50 cubic centimeters were drawn off with a pipette and reduced
to 10 centimeters by straining through No. 575 S. & S. hard-pressed
filter-paper. After this condensed sample was thoroughly shaken,

a Rafter cell holding one cubic centimeter was filled, and counts of
the liring plankton were made under a microscope by the methods
usually employed in preserved specimens. The above method of
collection is a slight modification of that recently used by Kolkwitz,*
dififering from it chiefly in the fact that the samples were condensed
before examination. The fundamental feature is the direct field

examination and enumeration of the living organisms in small sam-
ples, which in the practice of Kolkwitz were not strained or con-

densed in any manner.
This concentration process seemed to us to be called for to in-

sure a number of organisms in the samples examined, sufficient to

give a dependable count. The correctness of the method used is, in

our opinion, fairly attested by the general consistency and reason-

ableness of the figures obtained, if proper account is taken of the

known variability of hydrographic and chemical factors. A few
special tests of it were nevertheless made, (a) Duplicate counts of

collections from the same place on the same day showed neglible

differences only, (b) A collection obtained at Chillicothe August
17, containing a total of 162 organisms per cubic centimeter (not

counting bacteria,) was filtered, and a centimeter of the filtrate was
found to contain no organisms except a few bacteria, (c) A collec-

tion from Depue Lake containing 40,000 chlamydomonads per centi-

meter was filtered, and the filtrate contained only 147 green monads

Mitth. aus der Kgl. Preuss.- \iistalt fiir VVasserversorg. mid Abwasserbeseiti-
gung zu Berlin, igoT.



498

per centimeter, a residue of .3 of one per cent, which had escaped

through the filter-paper, (d) A Fox River collection made Sep-

tember 2, containing 3 161 organisms per cubic centimeter, yielded

in the filtrate 12.6 organisms per centimeter, less than .4 of one per

cent.

There was, of course, always some undeterminable loss through
adhesion to the filter-paper, but this was minimized by the large

amount filtered (50 cubic centimeters), and by thorough washing of

the filter during the removal of the 10-centimeter residue. To all

appearance the loss was very slight, and, the error being practically

uniform since the same methods were used throughout, it could not

invalidate comparisons.

Definition of Terms.—As a considerable part of this paper will

be given to a description of the criteria and effects of different de-

grees of contamination of the natural waters of the Illinois, we will

distinguish, as clearly as convenient, three stages of impurity, by

the use of the following terms applicable both to the waters them-
selves and to the characteristic organisms, given here in the order

of a diminishing impurity, namely, (i) septic or saprobic, (2) pol-

luted or pollutional, and (3) contaminated or contaminate; and to

these we will add "clean water" to indicate the conditions and organ-

isms substantially equivalent to those of the natural, uncontaminated

stream. These expressions seem sufficient!}' definite and significant

to distinguish between stages which at best can not be sharply marked
off; and we prefer them for our purposes to the equivalent highly

technical terms polysaprobic, mesosaprobic a, mesosaprobic ^, and

oligosaprobic, introduced by KolkAvitz and Marsson.

Only a very general account of the product of these collections

will be given at this time, the subject being reserved for more de-

tailed report in a later paper.

For a merely general and preliminary presentation of our data

of 191 1 relating to the midsummer microplankton of the upper Illi-

nois, we may conveniently divide the waters from which our collec-

tions were made into four sections or general situations, correspond-

ing to distinguishable stages of pollution and self-purification; (i)

the sanitarv' canal at Lockport, (2) the Des Plaines River at Dresden

Heights and the Illinois River from that point to Marseilles, and

(3) the Illinois River from Marseilles to Starved Rock, and (4)

from Starved Rock to Lockport,

In the sanitarv' canal at Lockport we found, in September, 191 1,

an abundant Lake Michigan plankton with little admixture of septic

organisms. It was largely composed of characteristic lake diatoms



499

and flagellate Protozoa of the Chlauiydoiiioiias type, still living and
in process of multiplication,— a fact easily understood, in view of

the recent origin of the water in the lake and its undisturbed flow
and relatively low temperature in the deep canal.

The Des Plaines River at this point was heavily loaded with
sewage wastes derived partly from the sanitary canal, which sends
into it an overflow through the turbine waste ditch of the controlling

works, and at times also through the sluice and over the bear-trap

dam at the same point. This stream was heavily contaminated also,

in 191 1, by sewage from several suburbs of Chicago on the Des
Plaines above Lockport. As it was very low and the water spread
in a thin sheet over a rocky bottom, its temperature was much higher

than that of the canal, and septic organisms were at their maximum.
The most conspicuous of these was the well-known "fungo-bacte-

rium," Sphccrotihis nutans, a filamentous form which grows in long,

loose, hanging tufts and branches in septic and polluted waters. The
stony bottom of the Des Plaines between Lockport and Dresden
Heights was carpeted with this plant, and with it were associated

a considerable variety of Protozoa (Carchcsiiini lachnianni, Vorti-

cclla )nicros!onia, Episfylis plicatilis, Oikouwnas tcriiio, Bodo saltans,

and Paranicciiun putriniun,) all characteristic foul-water species.

These were continually being torn loose by the swift current of the

lower Des Plaines and mixed with the free plankton, with which
they were carried far down the stream, feeding and multiplying as

they went, until a gradual purification of the water made it unfit

for their maintenance.

The Illinois from Dresden Heights to Marseilles was, in July to

September, 191 1, an especially saprobic or septic section of the

river, this condition culminating at Morris, if we may judge by the

numbers of septic organisms in the plankton. The most abundant

of these were Sphccrotihis natans, detached filaments of which made
about 90 per cent, of the number of the plankton organisms in this

and the following section. These were most abundant at Dresden
Heights, and were much more so at Morris than at any point below.

Several of the larger species of saprobic bacteria, not essentially

different in food requirements from Sphcrrotilus natans, were notablv

abundant in this section: Bacterium indgarc, Spirillum volutans, and

species of Streptococcus were common examples. The largest col-

lections of detached heads of the VorticcUidcc (Carchcsium lachmanni

and Epistylis plicatilis) were made at Dresden Heights and Morris.

Flagellate, colorless Protozoa which feed upon bacteria, were also

cxtremelv abundant in this section. The largest number<; of Oiko-



500

monas termo were found at Marseilles above the dam, and the num-

ber at Morris and below the dam at Marseilles was much larger than

at stations either above the former or below the latter point. It was

further characteristic of this section that one-celled green algx and

green flagellate Protozoa were nearly absent in its waters except for

survivors of the Lake Michigan contribution. Even the hardier

Lake Michigan diatoms were distinctly waning in numbers, their

moribund condition Ijeing plainly shown by the fading and breaking

down of their chloroplasts. On the other hand, many diatoms come

through this section alive, particularly the two species of Tabcllaria

(feiicstrata and Hoccidosa) together with some of the Synedras and

Naviculas.

The microplankton collections of the section from Marseilles to

Starved Rock agree with the longshore collections to the effect that

the septic organisms were diminishing rapidly here, Sphccrotilus and

Carchcsium disappearing from both the waters and margins, but

appearing in dredgings from the bottom of the channel, to which

these organisms had seemingly settled to die. Oikomonas tcrmo

also, the most abundant bacterium-eating protozoan, gave us an aver-

age of 2IO to the cubic centimeter above the dam at Marseilles, but

fell to an average of 54 to the centimeter at Starved Rock. The

Lake Michigan diatoms, on the other hand, continued in nearly con-

stant numbers, as did also the clean-water unicellular algre and green

Proto::oa.

In the Starved Rock-Chillicothe section of the river the outstand-

ing feature of the plankton was the marked increase in diatoms and

other clilorophyll-bearing unicellular organisms, plant and animal,

which became sufficiently abundant by the time Hennepin was reached

to give the water a characteristic greenish tinge. This was largely

due, however, to the picking up numbers of a single species of dia-

tom, Melosira gramtlata var. spinosa, a form common in the Illinois

River and especially in its backwaters. This "greening up" of the

water below La Salle was noticed, in fact, on a down-stream trip in

June, 1910, and was conspicuous to the naked eye in both 191 1 and

1912, most noticeably so at the lowest water-levels. Rise of water

and an increased turbiditv due to flooding rains in early August, igii,

obscured it for a time. It will presently be seen that these indications

of a radical change about Hennepin in the biological contents of the

water, are supported by the products of longshore collections, for it

is here that the foul-water blue-green algae began distinctly to dimin-

ish, that the Cladophoras and Stigcoclonitiiii lubricum began to take

the place of Sfigcocloiiiiiin fciiuc as the most abundant green a.]gx.



501

and tliat tlie amphipod crustacean, Hyahila knickcrhockcri, put in

its first appearance below Dresden Heights.

The Sanitary Canal at Lockport

Our data for the sanitary canal were obtained at Lockport, three

and a half miles above the lower locks through which the canal emp-
ties into the Des Plaines. They were derived from biological col-

lections made at this point September 25, 26, and 2y and November
I, 191 1, and August 9 and October 7, 1912; and from chemical de-

terminations made November i, 191 1, and February 7, March 18,

November i, and November 13, 1912. The biological data thus

represent the conditions of late summer and autumn, and the chemi-

cal data, those of autumn and winter, but neither apply directly to

those of spring or midsummer.
General and Chemical Conditions.—At the time of the first visit,

September 25, 191 1, the water of the canal at Lockport was clear,

like that of Lake Michigan, with much less silt and other suspended

matter than the Des Plaines at the same point. It had a slight

sewage odor, not particularly offensive ; and there was no emission

of bubbles of gas to indicate rapid fermentation or putrefaction of

its contents. Aliscellaneous offal and other refuse was floating or

stranded along the edge of the canal, much of it but little decayed.

In it were recognized grains of corn and wheat, melon seeds, tallow,

pieces of entrails, bits of human excrement, pieces of old newspaper

and toilet paper, fragments of finely chopped straw, and street sweep-

ings. The grayish sludge at the bottom of the canal had a foul privy

odor combined' with a tarry smell like that of the sludge from the

bottom of the Illinois River at Morris on the same date.

Under the colder weather conditions of Noveml>er i, 191 1, with

a surface temperature of the water at 50° F., the odor and general

appearance were practically the same as in September. There was
perhaps even less appearance of decay in the floating debris. Chicken

entrails floating in the water of the canal looked, in some cases, al-

most fresh.

August 9 of the following year the color, odor, and general con-

dition of the canal water were practically like that of September,

191 1. The water temperature was 64 to 65 degrees F. ; and the

depth of the water in the canal was three to four feet above that

of the fall of the preceding year.

The dissolving oxygen of the water, as shown by chemical tests,

ranged from .4 of one part per million November i, 1912, to 9.3



502

parts per million, February 17 of the same year. At the tempera-

tures of the time, the first of these ratios was equivalent to 3.5 per

cent, of oxygen saturation, and the last to 64.9 per cent. The aver-

age of the six observations made, was 4 parts of oxygen per million,

or 31.9 per cent, of saturation. The general conditions were thus

those of lake water rather heavily loaded with organic debris which

had not yet undergone any great degree of putrefaction.

Plants and Animals.—Consistently with this statement, in Sep-

tember, 191 1, a few small shiners {Notropis atherinoidcs) one to

two inches long, were alive in the water, although in a dying state;

but all the larger minnows of this species, together with many spot-

tailed minnows (A', hiidsonius), silvery minnows (Hyboguatliiis

nnclialis), and lake perch, were stranded, dead, along the shores. In

the cooler weather of November, 191 1, a larger proportion of the

shiners were alive, and a single large fish, possibly a carp, was in-

distinctly seen moving away from the riprap at the north shore. All

the fishes found, were common Lake Michigan species. A single

frog was the only other vertebrate taken.

A cursory examination of the bottom sludge November i, 191 1,

showed no signs of animal life; and the only insects seen in or on
the water were a back-swimmer (Notonecta) and several water-

boatmen (Corixa), both of which, as they breathe air, can afiford to

be indifferent to a deficiency of dissolved oxygen. No snails or crus-

taceans were found in the water at this place in either year. Along
the riprap at the edge of the canal in 1912 was a mixture of normal

and septic species of alg?e, with others representing medium stages

of contamination. The most abundant clean-water species were

Ulofhrix conaia and Schicouicris Icihleinu, barely submerged on the

riprap, where they were mixed with Oscillatoria liinosa, to be classed

as a contaminate species. There were occasional slight traces of

Spliccrotilus natans and Bcggiatoa alba, both highly distincti\-e of

septic or polluted waters, together with considerable growths of

Stigcoclonhim tennc (a contaminate form) and Chlorclla vulgaris,

the latter encrusting stones. Among the meshes of the marginal

alg£e were many septic Protozoa and rotifers (Bodo saltans, Vorti-

cella microstoma, and Rotifer acfimirus), together with others com-
mon in polluted waters (Oikomonas termo, Monas Z'ivipara, and
Anthophysa 7'egctans).

Des Plaines River, Lockport

September, igii.—In late September of 191 1 the Des Plaines at

Lockport was much more oft'ensi\'e than the sanitary cattal, its



503

organic contents being evidently in a far more advanced stage of

decomposition. The stream was very low, flowing, at a depth of six

inches to a foot, over stones and pebbles which were completely cov-

ered with a septic growth of Sfhccrotiltis and algre, mainly blue-green

species. The water had a grayish look, and a filthy smell, which
may perhaps be best described as a mixture of fishy and privy odors.

The current was too swift to permit the deposit of much sediment;

and it was frequently dislodging and carrying away fragments of

the incrusting growth from the bottom. A comparison of the con-

tents of the stream with those of the sanitary canal beside it pointed

to the conclusion that the septic organisms of the upper Illinois were
at this time being derived mainly from the Des Plaines and not from
the canal, although the putrescible matter carried by the latter fur-

nished an abundant nourishment for their growth and multiplication

far down the course of the main river. The Des Plaines was a seed-

bed, in short, and the canal water the soil, for the culture of sewage
organisms in the Illinois.

Our collections from the river at Lockport were made opposite

the Ninth Street Bridge, three miles and a half above the lower gates

of the canal. Splurrotilits natans and Anthophysa vegetans were
very abundant, with Carchesium lachmanni, Bpistylis pUcatilis, J'or-

ticella microstoma, and Paramecium caiidatiim intermixed. Less dis-

tinctly septic forms were Oscillatoria limosa and Stigeoclonium teniie,

with some Ulothrix conata. Among tangles of dirty Sphccrotihis

were found large numbers of Chironomus larvae, together with oli-

gochaete and nematode worms. No fish were seen here in Septem-

ber, the water being evidently much too foul for even the most in-

different species.

November, igii.—November i, IQII, the stream was six to eight

inches deeper, and the water temperature was 57° F., but conditions

generally were not unlike those of September, except that the odor

was less offensive. No snails or higher crustaceans could be found,

although there were now great numbers of mosquito larvae in the

water. There were also many shiners (Notropis atherinoides),

nearly all alive but mostly in a dying state, as if they had been car-

ried down by the current from above, and overpowered by the toxic

contents of the stream.

The content of dissolved oxygen was higher in the Des Plaines

than in the sanitary canal—22 per cent, of saturation in the canal

and 44 per cent, in the Des Plaines ; and virtually the same rela-

tions were found again in November, 1912. February 2, 1912, on

the other hand, the oxygen was nearly the same in both waters—9.3



504

parts per million in the canal, and 8.8 parts in the Des Plaines. The
same was true March i8, when 6.3 parts of dissolved oxygen were
found in the canal and 6.5 in the Des Plaines.

August and September, igi2.—Additional biological collections

were made August 9 and September 30, 191 2, with water tempera-
tures at 67° F. on the first date and 64° on the second. The stream
was rather low, with much vegetation, including water milfoil

{MyriopJiylhim), Elodca, pondweed {Potamogcton), etc., the first

two mainly on the west side. There was, in fact, a marked contrast

at this time between the two sides of the river, due to the fact that

the water of the east side was badly contaminated by a waste ditch

flow from the sanitary canal, and contained there the sewage organ-

isms noticed the preceding year. In the Cladophora of the west
side were many live minnows, sunfish, etc., with Spirogyra, Vauche-
ria, duckweed, and epiphytic green algse. Here also among the Cla-

dophora, on the west shore, were numerous crustaceans

—

Cyclops,

Simocephalus, and Ostracoda, together with Hyalella dentata and a

single specimen of Aselhis. On the east side there was an abundance
of Carchcsium on the stones, together with oligochaete worms (Tubi-

fex) under mats of Oscillatoria. Eristalis and Odontomyia larvje

were taken in the contaminated water; and Corixa and Zaitha and
larvffi of Simidium and caddis-flies among Cladophora on the west

shore. The mollusks obtained were Lynincca huinilis, Physa gryina,

and Plaiwrbis parvus and trirolvis; the first on the east side and the

others common on the opposite shore.

Des Plaines River at Dresden Heights

The midsummer condition of the mingled waters of the sanitary

canal and of the Des Plaines at the mouth of the latter was shown
by observations made at Dresden Heights, in July and August, 191 1,

where typical septic organisms predominated. From July 26 to

August I this water had a grayish, sloppy appearance, with a mingled
fish and privy odor. Sticks and stones were everywhere hung with
tufts of two of the most abundant septic organisms, Sphccrotilus

natans and Carchcsium lachmauni. These were being continually

torn loose from their attachments and carried down stream, where
they appeared abundantly in the plankton; and silt and other sedi-

mentary matter was kept churned up in the current so that there

was scarcely any accumulated sludge on the broken stones and
boulders of the bottom and dam. The temperature of the surface

layer of the water July 28 was 68° F. No fish could be found here



505

at this time, either dead or alive. It was here also that the largest

number of septic organisms per cubic centimeter of water was ob-

tained July 28 to August 3, by our modification of the Kolkwitz

method,— 186 per centimeter, as compared with 116 at Morris and

15 at Marseilles. Of the pollutional species, on the other hand, there

were 55 per cubic centimeter at Dresden Heights as compared with

169 at Morris and 35 at Marseilles, while of the contaminate forms,

there were 90 at Dresden Heights, 76 at Morris, and 28 at Mar-
seilles. The mixed origin of the waters at this point was especially

illustrated by the further fact that clean-water species averaged 209
per centimeter at Dresden Heights, 287 at Morris, and 270 at Mar-
seilles. At Dresden Heights, however, these were almost wholly

diatoms characteristic of Lake Michigan water, which had evidently

been brought down by the sanitary canal. The most significant of

these were two species of Tabellaria—T. feitcstrata and T. Hocciilosa

—together with Fragilaria ziicscens and Cyclotclla kiitzingiana. The
Tabellarias were never taken in our Illinois River plankton previous

to the opening of the sanitary canal, and their maximum number
in the Illinois in these 191 1 collections came from above Marseilles.

The other two species formerly occurred in both the river and lake,

but they were rare below Morris in July and August of 191 1—

a

strong indication of the Lake Michigan origin of those taken at Dres-

den Heights.

The water here July 2~, at a temperature of 68° F., gave us an

a\-erage of 13. i per cent, of oxygen saturation as the mean of de-

terminations made at 10 a. m. and i 130 p. m., the Kankakee River

giving us, on the other hand, just above the mouth, an average of

126.S per cent, at 2 p. m., at a temperature of 71.6° F. In other

words, the Kankakee, supersaturated with oxygen, contained nearly

ten times as much as did the Des Plaines just above the junction

point of these two rivers. The former held in solution, on the other

hand, only one sixth as much carbon dioxide—2.1 parts per million

to 12.8 parts in the Des Plaines. The oxygen content of the latter

was practically the same September 26, 19 12, as in the midsummer
period of the preceding year, but increased greatly in fall, reaching

40.3 per cent, of saturation November 14 as compared with 11.2 per

cent. September 26.

Biological conditions were but little changed in 191 2, as shown

bv visits made in August and September of that year. As before,

no fishes were found, and no other vertebrates except a single frog.

Many dead shells of gastropod mollusks were seen, including Planor-

bis trivolru, Physa gyriiia, and Lyimicca palustris, and a single speci-



506

men of the last species was found alive among algae in the drift.

Numerous Cluronomus eggs were in the same situation; and air-

breathing beetles

—

Dineiitcs and Gyrinus—were also common, but

there were no water-breathing larvse except Chiroiioiiiiis. Slime
worms {TiibiUcidcE) were rare in the soft black sludge at the bottom
and the edge of the stream—a great contrast with conditions at Mor-
ris to be reported later. Splucrotilus was again very abundant on
weeds and sticks, and on old stems of Carchesiuni lachinaniii. Blue-

green alg£e, chiefly Oscillaforia liiuosa and Phoniiidium unciiiatum,

were fairly frequent. The green filamentous alg;e, Stigeocloninm
teiiite, and Spirogyra, chiefly S. I'cniata, were common in both

August and September, and Ulotbrix coiiata in the latter month;
and some Lemna and JJ'olffia were caught in the drift along the

bank. Protozoa were represented mainly by fixed forms, especially

by Carchcsiitin, attached to sticks or floating in the water. There
were no sponges, hydroids, leeches, planarians, or crustaceans.

The general impression to be gained from these midsummer and
autumn data is that of a heavily polluted stream with less oxygen
and more carbon dioxide than was consistent with the life of fishes,

mollusks, insect larva;, or crustaceans, and with the natural tauna

of the stream represented by saprobic organisms, except at its edges,

where oxygen enough was absorbed from the air to serve the needs

of a few green algae and an insignificant group of associated ani-

mals. Decomposition of its sewage materials had not yet reached

its climax, which came at Morris and Marseilles at low water in the

hottest weather, and at various distances farther down when the

water was higher or the weather cooler,—farthest, of course, when
these conditions were coincident.

The Kankakee River at Dresden Heights

Conditions in the Kankakee at its mouth are particularly inter-

esting and important since they give us a close approximation to

those of the natural water of the Illinois River, derived, as they are,

from a territory similar in character to the valley of the Illinois

below, and contaminated but slightly, if at all at this place, by way
of contributions from comparatively small towns at some distance

above. Collections were made from the Kankakee at a point near

the east bank and two hundred yards above the mouth of the stream.

The samples were taken in two or three feet of water by wading

out or by working from an improvised trestle forty feet in length.

The river at this point is broad and shallow, with a moderately swift

current, probably two to three and a half miles per hour, becoming



507

much quicker, however, as it approaches the rapids at the junction

with the Des Plaines. The water was more or less yellow with clay

silt. The color, odor, and the organisms obtained, were those of a clean

and practically uncontaminated stream. The water temperatures at

the surface were 69.7° F. July 24, 72.4° July 26, 82.5° August 9, and

J2,° August 21.

Nine determinations of oxygen were made on different dates,

—

July 24 and 26, August 10 (forenoon and afternoon), and August
21 (forenoon and afternoon), 191 1; and February 19, September
26, and November 14, 1912. Four tests for carbon dioxide were also

made—July 26, August 10, and August 21 (forenoon and afternoon),

191 1. Six of the nine oxygen determinations showed that the water
was supersaturated, percentages ranging from 104.6, September 26,

to 133. 1 on the afternoon of August 10. The lowest result was
62.2 per cent, of saturation on February 19. The general average
of the nine determinations is 103.8. Forenoon and afternoon tests

for the same day were made August 10 ( 10 130 a. m. and 2 130 p. m.)
and August 21 (10:30 a. m. and 2 p. m.). Those for the forenoon
averaged 101.7 per cent., and those for the afternoon 12 1.2 per

cent. The afternoon increase was doubtless due to the liberation

of oxygen by submerged plants under the influence of sunlight. The
carbon dioxide found July 26 was 2.1 parts per million; August 10,

.7 parts; and August 21, none.

The biological conditions were those of a clean stream, there be-

ing no plants or animals obtained here in either year commonly
classed as saprobic—no blue-green algse, no Carchesium or other fixed

forms of Protozoa, no oligoch^ete worms, and no Sphccrotilns or

Beggiatoa. Green filamentous algae—mostly Cladophora glotueraia,

with some Microthamnioii and Vaucheria—many river mussels—the

greater part of which were, however, for some unknown reason

dead—and several water snails (Goniobasis), were among the com-
moner clean-water forms.

Illinois River at Morris

The water here was grayish, sloppy, and everj'where clouded with

tufts of SpJicvrotihts and Carchesium. The odor was continuously

foul, with a distinct privy smell in the hottest weather. Bubbles of

gas were continually breaking at the surface fronr a soft bar of

sludge formed along the north bank between Kindles])ire's landing

and the Mazon bridge. On the warmest days putrescent masses of

soft, grayish black, mucky matter, from the diameter of a walnut

to that of a milkpan, were (loating on the surface. These masses.



508

held together by threads of a\gx and fungi and growths of branching
colonial bell-animalcules, rose from the bottom buoyed up by the

gases developed within them, but settled quickly when they were
broken apart by a light touch. Noticeably cleaner water, with a less

offensive smell, carrying also much less Sphccrotihts and Carchcsium,
was found along the south shore, where the Kankakee contribution

still had a discernible influence. The water temperatures of the

surface layer were 69.1° F. July 28, 73° August 11, and 73° August
23-

October 11, when the water was three feet higher than in August,
conditions were greatly improved, the water being much less offen-

sive in odor, with no bubbling of gases and no floating masses of

detached sludge. The feathery tufts of Sphccrotihts and Carcliesium

were also much less abundant. Virtually the same statement may be

made for November 3, when the river level was about two feet above
that of the midsummer season, and for November 13, when it was
two or three feet higher still.

Imperfect Mixture of Waters.—A study of conditions at Morris
was made difficult by the fact that the waters of various origin flow-

ing past that point were not yet thoroughly mingled, those of the

Kankakee predominating along the south bank and those of the Des
Plaines River and the sanitary canal along the north bank, while

the midstream current was made up of a variable mixture of the

two. This was most plainly shown by a comparison of the chemical

reports of the oxygen content of the water, on the same days but on
opposite sides of the stream. Determinations of oxygen, available

for this comparison, are as follows, stated in percentages of satura-

tion.

Date



509

saturation with oxygen for the southern, or Kankakee, side were

113 per cent, larger in September, 191 1, than those of the northern,

or Des Plaines, side; 34.5 per cent, larger in November; and 13.9

per cent, larger in February and March, 19 12. Flooding rains, on

the other hand, tend to increase the difference and to carry it further

down the stream. The clean Kankakee being a much larger river

than the polluted Des Plaines, the effect of a strong rise in these

streams is to increase the ratio of south-side unpolluted water to

north-side polluted water, and to carry a larger volume of the former

down to Morris and even to Marseilles, with less admixture than at

low-water stages. This condition was illustrated by observations

made November 3, 191 1, when recent heavy rains had brought the

river up about three feet. Midstream ratios, samples for which were

taken from what was obxiously Des Plaines Ri\-er water, averaged 4.6

parts per million of oxygen, while south-shore samples (Kankakee

water) contained 10.8 parts per million. The water temperature at

this time was 41° F.

All our midstream samples were taken for analysis as near the

center of the river as practicable, and usually from a depth of eight-

een inches or two feet below the surface. Midstream ratios aver-

aged 7.3 per cent, of saturation in July, 191 1, 16.37 P^r cent, in

August, 28.5 per cent, in November, and 48.76 per cent, in February,

1912. In September, 1912, they stood at 17.9 per cent., and No-
vember 14 at 57.2. This is the highest of our midstream readings;

but a still higher one might have been obtained March 19, 1912,

when even the north-shore ratio was 65.4 per cent., or 9.2 parts per

million, with a temperature of 34.7° F.

Oxygen determinations were made on the same date from both

sides and from the center of the river on only three days—February

16, Septeml>er 27, and November 14, 191 2. On these days the mid-
stream percentages were much nearer to those of the northern or

heavily polluted side than to those of the southern or lightly con-

taminated side, the mean difference being 3.7 per cent, in the first

case and 48.4 per cent, in the second. In this we may probably see

the effect of the wing-dam at the mouth of the Des Plaines in forcing

the water of that stream well across the Illinois, leaving a compara-

tively narrow strip of imperfectly mixed Kankakee water along the

south bank.

Bxtrcinc Midsiimuicr Conditions.—The Io\\'est ratios of oxygen
at Morris were those of July 22, 1911, when samples were collected

from the middle of the stream and from the south bank only, the

former at a depth of five feet, and the latter at three feet below the



510

surface and forty feet from the bank. The south-shore samples aver-

aged .21 parts per million, which, at the temperatures of the time,

was equivalent to 2.65 per cent, of saturation, the corresponding fig-

ures for the midstream samples being .267 parts per million, or 3.1

per cent, of saturation. The water temperatures on this date ranged
from 66.7° F. at 10 a. m. to "]"]' at 1 130 p. m.

Midstream samples showed no increase of oxygen in the after-

noon, the parts per million, July 22, being .30 at 10 a. m., .26 at

1 130 p. m., and .24 at 4 p. m. ; but those taken forty feet from the

south bank were .04, .28, and .31 for the same hours, respectively.

The effects of sewage contamination are clearly shown by a com-
parison of these data with the Kankakee determinations of July 24
and 26, both made at 2 p. m., which stand at 9.91 parts per million

for the first date, and 11. 21 parts for the second—equivalent to

107.9 ^"d 126.8 saturation percentages, respectively. The means of

the Morris determinations for afternoon hours were thus but 2.3

per cent, of those for the Kankakee; in other words, over 97 per

cent, of the oxygen normal to these waters had been removed from
them at this time by decomposition processes due to the amount of

their organic contents.

The Bottom Sludges.—The silt and other deposits accumulating

on the bottom of a stream are in some respects more significant of

its average condition than are the waters of its current, especially

so as many of our fishes obtain the greater part of their food from
the bottom, upon which most of the plants and animals necessary to

their support live continuously. The current opposite Morris is so

rapid that the bottom is practically clean of sludge except where
eddies and slack-water places are especially favorable to sedimenta-

tion. An extensive bar of sludge from three to eight feet deep has

been formed in such a place between the wagon bridge and Kindle-

spire's landing, along the north shore of the Illinois. The upper two

or three feet of this deposit, except for a thin upper stratum of

grayish color, is a soft black ooze of homogeneous composition and

a strong offensive odor. It contained, from September on, immense

numbers of tubificid worms, in which respect it differed from the

canal deposits at Lockport, which reached at the controlling works

a depth, in places, of three or four feet. Plates of this sanitary-

canal sludge spread out in thin layers and kept for thirty-six hours

showed to the naked eye no signs of life.

An extensive deposit of sludge, five or six feet deep in places,

has formed at the lower end of a large island half a mile above the

Marseilles dam, and sediments a foot or more in depth have accumu-

lated also in the chutes on each side of this island. In the north



511

chute, the main channel of the stream, the sediment was fine, heavy,

black, and but little offensive, and contained few tubificid worms,
the lighter organic matter evidently being carried down by the cur-

rent; but in the more sluggish water of the south chute it was light,

soft, and grayish, and full of Tubificidcr. For the first half mile

above the dam the river bottom is mostly rock, covered by a thin

layer of very soft ooze; but below the dam the swift flow of the

stream keeps the bottom bare.

The chemical condition of the bottom deposits at this time is

sJiown by the following table of the results of analyses of gases col-

lected from the bottom sediments of the Illinois, at Morris, in

August, 191 1.



512

Collections of the bottom gases were made again at Morris Sep-

tember 5 ; and witli a view to learning how far down the stream the

bottom conditions fomid at this point were continued, hke collections

were made at Henry September 6, and above the dams at Marseilles.

The chemical results are as follows.



513

inorganic materials of the silt. As there is no reason to suppose that

the river was carrying a larger load of mineral substances at Henry
than at Marseilles, the differences of the table are probably due in

part to a settling out, and in part to a decomposition of organic con-

taminations before the river water reached the Henry dam.*
Marginal Conditions, July, ipii.—The septic conditions above

described were general at ]\Iorris for the stream as a whole, but were

considerably modified along the margin in very shallow water, es-

pecially in pockets protected against the current. Water an inch deep

near the north bank contained 3.5 parts per million of oxygen in the

forenoon of August 31 and 6.1 parts in the afternoon, (38.9 per

cent, and 69 per cent, of saturation,) while midstream samples gave

1.05 and 1. 18 parts per million at the same hours (11.4 per cent,

and 13.3 per cent, of saturation). The green-thread alga, Stigeo-

cloniuni tciiue, formed many patches on the bottom even in July, in

water four to six inches deep; and the oxygenation of the marginal

water was largely the work of these plants. Here also were very

many tubificid and naiid worms {Tiibifex and Dero furcata), together

with aquatic insects (Notonccta, Nepa, and Gyrinidcc, and a few

Chiroiioniiis larv?e) ; but there were no clams (Unionidcc) or snails

or crawfishes or larvje of May-flies or of dragon-flies.

Plants and Animals of the Stream in general, July, ipii.—Gen-

erally speaking, the plants and animals of this part of the river in

July, 191 1, were either conspicuous by their absence, if clean-water

forms, or by their excessive abundance, if pollutional or contaminate

species. Sphcvrotilus natans, for example, was hanging to every

stick or grass-blade along the edge, and to every suspended particle,

small or large, and was attached everywhere to the stems of branch-

ing J'orticcllidcr, especially to Carchcsium lachmanni. Specks or

larger collections of these two latter most abundant foul-water forms

were so numerous, indeed, as to give the water a grayish look. There

was every indication that these characteristic sewage organisms were

coming at this time mainly from the Des Plaines above the mouth

of thecanal, and not directly from the sanitary canal itself, in which,

in fact, they were not then abundant. The microscopic population

of the large, soft masses floating down stream at Morris in July was

mainly made up of a great variety of fungi, alg?e. Protozoa, and

rotifers, of which the most abundant were Sphcrrotilus nataus, Os-

cillatoria limosa, Colpidium colpoda, Carchesium lachmanni, and Roti-

fer actinurus.

No fishes were seen or heard of here in the Illinois during this

*For additional data concerning the sludges in the winter time, and for all

sections of the river, see p. 552.



514

month, although they were abundant in Mazon Creek, and in the

slough at its mouth, which opens into the Illinois at Morris. Carp
were noticeably numerous in this slough, and could be seen any

sunny morning lined up along the edge of the river current, oc-

casionally venturing into it a short distance, but quickly returning.

After August lo, when rains brought the river up about six inches,

the carp began to come out of the slough into the river along the

south bank.

Late Summer and Autumn Conditions, iqit.—Towards the end
of July, cooler weather and higher water produced changes which
presently had their effect on the life of the river. The midstream
temperature was 6.7° F. cooler on the 28th of July than it had been

on the 22d, and a heavy rain August 10—the first excepting one

light shower since our operations began, July 15—brought the river

up about six inches. The fall rains began about the middle of

September, and the river rose until, by October 5, it was four to five

feet above the mid-July level. It then fell slowly about three feet

in October, was brought up again a foot by November 11, and by
the end of that month had declined to two and a half feet above the

July stage. Water temperatures in the midstream ranged from 63°

to 72° F. in August and September, and by November 3 (at 9 a. m.)
were down to 41°. The midstream oxygen ratios of this late summer
and autumn season averaged 1.44 parts per million in August, and
stood November 3 at 4.55, or 16.5 per cent, of saturation for August
and 41.3 per cent, at the beginning of November.

Reappearance of Fishes and other Animals.—By October, fishes

had begun to appear to some extent in the river, even along the

northern or contaminate side, where a few young perch, shiners

(Notropis atherinoidcs), straw-colored minnows (N. hlcnnius), and

a single top-minnow (Fiindulus notatus), were taken in places pro-

tected from the strong current. Shiners and straw-colored minnows
were seen again in the same situations November 3, and carp were
occasionally noticed on the south side of the river during the latter

part of October. December 2, the first systematic attempt to take

fishes at Morris was made, by hauling repeatedly a hundred-and-

twenty-foot minnow seine in slack water along the north bank. Al-

though weeds and sticks were slimy with Sphccrotilns nafaiis and
Carchesium lachinanni, which were also floating in the shallows,

numbers of young perch three to six inches long were captured here,

together with many shiners—two to four inches^—and a single black

bullhead (Ameiurus vielas), three inches long. An examination of

the stomachs of these specimens showed that none of them had



515

recently taken food; but no other evidence of any abnormal condi-

tion was found.

Other and smaller animals, not detected in July, also made their

appearance here as the season advanced. Water snails {Planorbis

and Lymncca) were seen on the south side of the river in August,

and specimens were repeatedly taken on the north side from the

first of September on. October 28 a large crawfish was noticed, ap-

parently distressed however, and trying to leave the water. Large
numbers of Bntomostraca (Cyclops prasiinis) were taken in the

stream October 13, although only a few dead nauplii had been col-

lected previous to that time. Female Cyclops bearing eggs were no-

ticed in shallow water in protected pockets along the north shore

after the September rise had scoured the river out. From November
I to 8, healthy Bntomostraca, largely a species of Diaptomus, were

taken in considerable numbers both here and in the sanitary canal

at Lockport, and free living nauplii were common in the collections

from the sanitary canal.

Winter Conditions, igi2.—Winter conditions in February and

March of 1912, when the river at Morris was partly frozen, were

naturally in notable contrast to those of the midsummer season. The
river level was unusually low for the winter, ranging from six inches

to a foot above that of the preceding August. The water temper-

atures were, of course, near freezing. The mean of nme observa-

tions made February 16 was 33.8° F., and that of two observations

made March 19 was 34.7°. There was doubtless no less organic

matter in the water than before, and the sludge from the bar on the

north side had now a strong privy odor, as of undecayed human
feces, in place of the merely rank smell of the warmer weather. The
water itself had a sloppy odor, and was apparently carrying more
Carchcsium lachmanni than in midsummer. Decomposition being,

however, much slower at the winter temperatures, the o.xygen content

of the water was relatively high, ranging, February 16, from 6.3 to

7.2 parts per million, equivalent to an average saturation percentage

of 48.76 for midstream samples.

The Winter Search for Fishes.—^Persistent efforts were made at

this time, under unusual difficulties, to learn whether fishes were to

be found at Morris under these winter conditions. The use of min-

now-seines, river-seines, and fyke-nets, was supplemented by re-

peated explosions of half-pound sticks of dynamite in different parts

of the river. To haul the seines it was necessary to cut out the

shore ice to a depth of one or two feet in order that the nets might

be landed. In this way a dozen hauls were made with a 150- foot



516

seine of one-inch mesh. The nets fished weU, as a rule, as far as

seventy-five feet from shore, in the fuU current with water four to

nine feet deep, but no Hving fish were taken by any of these hauls.

Two dead shiners were in the net February i8, and a small specimen
of the same species, in a dying condition, was picked up by hand
near the shore February 24. It had perhaps been washed in from
Au Sable Creek. A hoop-net, with a 6-foot opening, and two smaller

fykes with 2-foot and 3-foot openings were kept continuously fishing

from Februarv 20 to March 2, alternating between the north and
the south shores, but not a fish was taken by them at any time.

Twenty-four sticks of dynamite were exploded on both sides of the

river and in the midstream, but the only fish to appear was a single

shiner, near the south shore, a hundred yards above the mouth of

Mazon slough. February 28, a neighboring farmer found a 15-

pound carp on the ice near the north shore below Au Sable Creek.

The fish was probably sick or suffocated, and trying to get air. On
the 2d of March, several perch and shiners, and a single carp eight

or ten inches long, were taken in cleaning out the pump-house tank

of the Rock Island Railroad, the intake of which is seventy-five feet

from the north shore of the stream. As the tank had last been

cleaned February i, these fish must have been pumped in since that

date. The stomachs and intestines of all the specimens taken at

Morris between February 16 and March 2 were quite empty.

Summer and Fall of igis.—In August and September, 1912,

Morris Avas twice visited for systematic collections of fish and of the

shore and bottom forms of animals and plants—the first time August
I to 10, and the second, September 23 to October i. The river level

stood, in the beginning, at twenty inches above the July stage of

191 1, fell slowly to eight inches above by September 22, and then

rose to eleven inches by the end of the month. Specks of suspended

matter, largely Sphccrotilns and Carchesinm, gave the water a gray-

ish hue, and its smell was the same as in the siunmer of 191 1, but

less offensive. There was also less bubbling of gases from the bot-

tom, but the odor of the sludge was not noticeably different.

Chemical determinations were made during this period only on

the 27th of Septeml>er, at which time, with a water temperature

of 62.7° F., the oxygen reading for both the north shore and the

main stream was 17.9 per cent, of saturation (1.8 parts per million),

and that for the south side was 37.4 per cent. (3.7 parts per million).

Persistent 'fishing was done with dip-nets, seines of various sizes,

set-nets, trammel-net, dynamite, dredges, and the mussel-bar,—the

last for Unios. Seven fishes were taken at this point in all—five of



517

them black bullheads (Aviciunis mclas), one a rock bass {AiiiblopH-

tcs rupcstris), and one a blue-gill sunfish (Lcpoiiiis paUidus). These
were all taken in set-nets in the less polluted water of the southern

or Kankakee side of the river^—the bullheads near the outlet of Mazon
slough, and the rock bass and sunfish about seventy-fiA'e yards above.

They were the entire product of a haul of the 200-yard seine, made
on the north shore August 2; five settings of the trammel-net on

the south side of the river; continuous fishing with three and four

set-nets August 2 to 9; fifteen hauls with small seines made on both

shores, September 25 ; and the explosion of twenty half-pound

sticks of dynamite, August 2 to 9, near both shores and in the middle

of the stream. The river here was, in fact, practically destitute of

fishes, and the few taken were in close proximity to the Mazon
slough. Moreover, some of the bullheads were "fungused" or in

otherwise unwholesome condition.

The only other vertebrates taken here were a single frog, two
snapping turtles, and a soft-shelled turtle. The search for mollusks

yielded seven species of mussels, all the specimens dead, however,

except for one collection made in -Mazon slough. Snails were ob-

tained several timesi

—

Caiupcloma, Goniobasis, and Platroccra all

dead, but Planorbis, Physa, and Lymncca alive in part, six collections

containing living specimens of these genera and nine collections

containing dead. No Sphccriiiui or Pisidiuin were taken here, nor any

Bryozoa, sponges, or hydroids.

Numerous samples of sludge from the bottom were spread in thin

layers on plates, and left for the animals to emerge, with the result

that tubificid worms appeared in numbers varying from 12 to 200

per plate. These were most abundant in samples taken nearest the

shores. There were no leeches or planarians in our collections, but

four of them contained naiid worms (Dcro furcata). A single

crawfish was taken in Mazon slough, and bleached, unwholesome-

looking specimens of an amphipod crustacean (Hyalclla kuicker-

bockeri) were present in the duckweed along the south bank. Sev-

eral species of water-beetles and water-bugs were found along both

shores, but, with the exception of larvas and pupre of Chiroiioiiuts,

these were all adults which take their oxygen from the air and not

from the water. There was some pondweed (Pontcderia) and duck-

weed (Lemna and Wolifia) along the banks.

No later collections were made at Morris in 191 2, but we have

additional oxygen determinations for November 2 and November

14. The following table gives these data for the midstream and the

two shores on these two dates.



518



519

negligible in amount or due to local conditions. In November, 191 1,

however, after a flooding rain which brought the river up some three

feet, midstream water above the dam contained thirty per cent, more
oxygen than north-shore water below the dam—a relation the re-

verse of that found at this point at any other time. This can only

be understood as due to the fact, already commented upon under
Morris, that, at this stage of the river, Des Plaines and Kankakee
waters were still imperfectly mixed even at Marseilles. The mid-

stream samples, taken nearer the south shore than the north, were
evidently Kankakee water, and the north-shore water, on the other

hand, was still essentially that of the Des Plaines.

In July and August, 191 1, when the midstream microplankton of

the river was collected at several stations between Dresden Heights

and Chillicothe, specimens of septic species were nearly all Sphcc-

rotilits natans. In the first collections, made during the last days of

July, this species was the most abundant at Dresden Heights, con-

siderably less so at Morris, and almost insignificant in number at

Marseilles, the actual figures of individual specimens per cubic centi-

meter of water for those three points being 186, 117, and 9 respec-

tively. Counts of Carchesiuin and Epistylis, also saprobic species,

were likewise much below those at Morris. A like difference in the

yields of septic species between Morris and Marseilles was found in

the collections of August 11 and t2 and August 23 and 24, when
the average numbers per cubic centimeter were 62 and 12 for these

two points respectively. This reduction in numbers down stream

is probably to be understood, however, as mainly due to a mere
settling out of particles carrying these organisms, and not to a change
in the character of the water.

We have no exactly comparable chemical data for July; but

analyses for August show oxygen ratios of 20.4 parts per million

at Morris on the nth and 11 parts at Marseilles on the 12th, and
of 16.35 pa-rts per million at Morris on the 22d and 23d and 7.4

parts per million at Marseilles on the 24th and 25th. The carbon

dioxide ratios, on the other hand, were much larger at Marseilles

than at Morris on these dates. Active decomposition of organic mat-

ter was thus clearly evident in this midsummer weather, at the low

stage of water then prevailing. With higher water and cooler weather

the differences between Morris and Marseilles were greatly dimin-

ished, the percentages of saturation February 16 to 20 standing at

48.76 for Morris and at 43.70 for Marseilles. In the fall of the

following year these ratios were, in fact, reversed, the Marseilles

determinations being 5 per cent, higher than at Morris September

27 and 9 per cent, higher November 14.



520

Alongshore July and August collections, in 191 1, were similar to

those at Morris, consisting mainly of Sphccrotilus iiatans, rather

less abundant than above, and Stigeoclon'uDii tcnuc, found only in

shallow protected places. Here also were back-swimmers {Notonec-
tidcc), a few Chironomns larvae, and miscellaneous oligochsete worms^
A few crawfishes were captured inside or near the mouths of creeks.

No Unios were seen here, either dead or alive; but a small bivalve

mollusk (Sphccriiim transversuni) was abundant in protected pockets
along the north shore in water six inches to a foot deep, and a few
living specimens of Physa, Lynuicra, and Plaiwrbis were taken in

similar situations. The bottom sludge contained at this time the

same slime worms {TubiUcidcc) as were found at Morris, as many
as fifty per plate near the south shore in October, 19 12.

In August and October, 1912, our more extensive collections gave
us a larger list of species, of which only the most significant will

be mentioned here. Besides the septic Sphccrotilus, Carchcsium, and
Episfylis, which were less prominent than above, but still everywhere
abundant, there were, at Marseilles the three blue-green algse, Lyng-
bya versicolor, Oscillatoria li)nosa, and Plwniiidiuiii iincinatum, the

two latter of which are classed as pollutional and contaminate, re-

spectively. The filamentous algse most frequently obtained along
shore were species of Stigeocloniiim, Cladophora, Spirogyra, and
Ulothrix, mentioned in the order of their abundance in our collec-

tions.

The organisms of the sludge, were, of course, the same as those

of the preceding year. A marked difference was noticed between

the chutes on the opposite sides of the island which divides the river

a short distance above the falls. The current in the south chute

is relatively weak, and the bottom sediments here were fine, light,

and full of sludge wonns; while in the strong current of the north

chute the silt was denser and darker, with few or no Tubifcx. Oli-

gochjEte worms, including naiid species, were found also in the ooze

along shore, especially abundant among growths of the blue-green

alga Lyngbya. Leeches were only occasional. There were no shore

or bottom crustaceans seen at Marseilles except certain species of

Cyclops, abundant among algje and duckweed along the margin of

the river, and a few crawfishes found only at or within the mouth
of a small tributary creek. Our collections of adult insects made at

this place represent fourteen genera, but the larvre, except those of

moscjuitoes and horse-flies (Tabanidcr), found each in but one col-

lection, were those of Chirononnis. Both blood-red and yellow spe-

cies with pupae and unhatched eggs were obtained in twenty-one

collections. No living Unios were secured either above or below the



521

dam, although the mussel-bar was diligently used in both places. A
small bivalve mollusk, Spharium transvcrsimi, was abundant along

the north shore; and the univalves were much the same as at Mor-
ris. Living specimens of the following species were collected

;

Lyiiuicca desidiosa, L. huuiUis, L. rcflcxa, L. palustris, Planorbis tn-

z'okis, SnccUica oralis, Physa gyriiia, and Polygyra midtilineata—
the last alive in only one collection.

The yield of our fishing operations was somewhat more varied

at Marseilles than at Morris, but only in the immediate neighborhood
of small creeks and springs, where the water was locally or tempo-
rarily more tolerable than in the main stream. No trace of fishes

was found above the Marseilles dam during July or August, 191 1;
and it was not until October 13 that a few minnows (Cypriiiidcc),

not identifiable at the distance, were seen near the north shore a

quarter of a mile above the dam.

November 30 and December i, 1911, hauls were made with a

1 20- foot minnow seine and a 150-foot one-inch mesh seine, on both
the north and south shores, some three eighths of a mile above the

dam ; and in the vicinity of small creeks. Many young perch and
shiners (Notropis afhcriiioides), a black bullhead, and a young carp

were captured here at this time. None had taken food except two
perch, one of which had eaten a small shiner and the other a naiid

worm. February 20 to 29, 1912, two 6-foot set-nets, kept in place

along the north shore, were lifted daily, a 120- foot minnow seine

was hauled in water two to four feet deep, and 26 half-pound sticks

of dynamite were exploded on both shores and in the mid-channel. No
fish were taken in the set-nets ; a single small shiner was caught
with the minnow seine ; and two perch and several shiners were got

with dynamite. The stomachs of all were empty.

In August and September, 1912, conditions were similar to those

found at Morris at the same time. Set-nets were raised every day
from August 13 to 17, but without result; and a dozen half-pound

sticks of dynamite were exploded, but no fish were taken. Small
seines were used on the north and south shores, and the fishes thus

caught, within or near the mouth of a small creek on the northern

side, were as follows : black bullhead, i ; common sucker, 2 ; striped

sucker (Minytrcma inclanops), i golden shiner (Abrainis chrysoleu-

cas), I; bullhead minnow; (Cliola zigilax), 12; straw-colored min-

now (Notropis blennius), i; young crappie, i; rock bass, 6; pump-
kinseed (Eupo)uofis gibbosus), i ; orange-spotted sunfish {Lcpomis
huiiiilis), i; and Johnny darter (Bolcosoiiia nigrum), 4. On the

night of August 19, a heavy rain, which flooded the small creeks.



522

washed fishes out into the river, where they became sick from sew-

age and could be picked up easily with a dip-net. The following

morning a 3-pound carp, 2 horned dace (Semotilus atromaculatus),

and an orange-spotted sunfish were obtained in this way. Several

hauls with small seines were made October 4, but no fish were caught

except a few bullhead minnows at the mouth of one of the creeks.

Beloiv the Dam.—Turning now to the situation below the dam
at Marseilles, we find that in July and August, 191 1, the ratios of

dissolved oxygen three fourths of a mile below were more than three

times as great as those just above* ; that under winter conditions

in February and March they were 13 and 14 per cent, greater; and

that in August and September, 191 2, with cooler weather and higher

river levels than in the previous year, they varied from one and a

half to two times as great. The necessity of taking samples for

analysis at some distance below the fall was shown by the fact that

the oxygen content of the water September i, 191 1, an eighth of a

mile below, was more than ten times that alx)ve—a discrepancy to

be accounted for only on the supposition that the air mechanically

caught in the water at the fall had not yet had time to escape. The
water l^elow the fall in 191 1 was visibly cleaner than that above, and

there was less Sphccrotilus nataiis in the plankton collections. This

was probably due in part to sedimentation in the slack water abqve

the dam, and in part to the pulverization of the coarser organic parti-

cles by the pounding of the water at the fall.

We were told by observant residents, in 191 1, that fishes usually

come up to Marseilles in some variety—bass only in the highest water,

but carp in both summer and winter of every year; but none of

either were seen or heard of there in July and August of that year.

Strings of black bullheads were being caught below the dam Octo-

ber 13, 191 1, and carp were said to have been common there since

the fall rains began. Our winter fishing with set-nets and dynamite

was, however, no more productive than at Morris. Small nets set

in February, 191 2, from one hundred to two hundred yards below

the dam, near the north shore, caught only two shiners, and were

then destroyed by floating ice; and six sticks of dynamite, exploded

from a half to three quarters of a mile below the dam, gave us only

two more of the same species. The stomachs of all these fishes

were empty.

August 14 and 15, 1912, we found essentially the same conditions

as to fishes below the dam which were found above, except that we

*It was impossible to reach the center of the stream here, and samples were
taken from the stern of a skiff fifteen feet from the north shore, in water two
feet deep. The current at low water. July 31, was estimated at five miles per hour.



523

got a greater variety of species in shallow water along shore near
the mouths of small tributaries. From the full current of the river

only a dozen specimens of a shiner (Notropis atherinoides) were
captured, and these by dynamite explosions, the set-nets coming up
empty. By the use of small seines and dynamite we obtained in

shallow water along shore examples of the species shown by the fol-

lowing list.

Fish Coukctions, Below the Dam, Marseii,i,ES, August 14 and 15, 1912



524

the more delicate of the Protozoa were killed by the pounding of

the falling water. Univalve mollusks were not only living, but were
breeding here August 25 ; \vhirligig beetles—mostly Gyriniis analis—
were common; large isopod crustaceans

—

Asclliis—were taken here

for the first time; and ai few slime worms (Titbifcx) were found

where soft mud was deposited in sheltered places, the current being

too swift for any considerable accumulation of bottom sediments.

In respect to organisms of other classes, the differences above

and below the dam were merely trivial, unless we may attach some
importance to the fact that our first specimens of the bryozoan

Plumatclla rcpcns, were taken below. This species was not found

above Marseilles, but occurred regularly at the various stations from

that point downward.

Ottawa

No collections were made at Ottawa in 191 1; and the several

oxygen determinations of September 2 of that year are of little use

for comparison, since the samples were all taken near the south

shore above the mouth of the Fox River, from only six inches be-

low the surface, in water but two feet deep. They averaged 5.34

parts per million, or 63.1 per cent, of saturation. The carbon diox-

ide on this date varied from 4.2 to 5.5 parts per million, with an

average of 4.66.

August 22, 191 2, oxygen tests from each side of the river above

the Fox, averaged 3.65 parts per million. November 2 the water

of the Illinois above the Fox gave 5.7 parts per million; and that

of the Fox itself nearly twice as much (11.2 parts per million).

In 19 1 2, biological collections were made here for seven days,

August 22 to 28 inclusive. Dip-nets, small seines, dredges, the mus-

sel-bar, and dynamite, were variously used, according to the situation

and the object in view. The water at this time had a distinct sew-

age odor, somewhat less noticeable, however, than at Marseilles, and

among the weeds along the banks was an oily, tar-like scum similar

to what had been noticed in the sanitary canal at Lockport. It ap-

parently originated in gas-house wastes. Other more or less recog-

nizable objects from the sewage were more abundant here along

shore than usual, possibly because a heavy rain which had fallen three

days before, bringing the river up about a foot, had flushed out

the Des Plaines.

The river sludge obtained at various points did not differ appre-

ciably from that above, either in sensible character or in organisms

contained, except for the occurrence of a few living snails and speci-



525

mens of the bivalve mollusk Sphccyiiiiii, found in a somewhat sandy
deposit two hundred yards below the Ottawa wagon-bridge. The
characteristic foul-water organisms, SplurrotUus, Carchesium, etc.,

although common in weeds along the edges of the stream, and ob-

tained also from the current, were less abundant than at Marseilles.

The same blue-green and filamentous green algae found at Marseilles

were collected here also. There were no sponges, hydroids, or pla-

narians; but leeches occurred now in fourteen collections. Cyclops

was found among the marginal algae, as above, and a single isopod

crustacean, Ascllus, was taken in the drift on the south shore.

The lessening of contaminate conditions was especially shown by
the occurrence of small numbers of various insect larvae, including

those of dragon-flies, caddis-flies, and May-flies {Ccents and Hc.va-

genia), and pupae of the sand-fly {Simulium). Larvae and pupae of

Chironoimis were obtained in twenty-two collections. Diligent use

of the ci'ow-foot dredge in various situations brought to light no
living mussels except on a bar in Fox River water just outside the

mouth of that stream. Here two species were obtained alive

—

Lampsilis ventricosa and L. laz'issiina—and dead shells of eight other

species. One large specimen of Aiwdonfa coj-pulenta had quite re-

cently succumbed, the flesh being not yet decayed.

Species of univalve mollusks, taken largely by the Ekmann dredge
from the bottom of the main stream, became at this point rather too

numerous for special mention in a preliminary report. Plaiiorbis

trk'olvis and Physa gyrina were the most abundant, and a species of

Amnicola next. The number of dead shells of both Unios and uni-

valves, as compared with the living specimens found, was indicative

of an environment still difficult for mollusks.

Our fish collections at Ottawa were made August 26 and 27,

1912, with small seines and dynamite. They aggregated one hundred
and twenty-five specimens, representing seventeen species, of which
forty-six specimens belonging to fourteen species were from Fox
River water just outside the mouth of that stream. From the water
of the Illinois itself, we have the following six species: i carp,

I black bullhead, i red-horse, 2 blunt-nosed minnows, 2 horned dace,

and 69 shiners, 18 more of the last coming from the Fox River water.

The seines gave us fifty-eight specimens of fifteen species; and
the dynamite explosions, sixty-seven specimens of six species. Only
two %f the latter, the carp and the horned dace, were secured by

dynamite which did not also come out in the seines. The following

is the complete list.



526

Fish Collections at Ottawa, August 26 and 27, 1912



527

From a comparison of the first column of this table, showing the

collections taken from the shallow water near the mouth of the

Fox, with the other columns, it is plain that Fox River water was
greatly preferred by fishes at this place, and it seems likely indeed,

that most of the specimens taken at this point had come into the

river from the Fox itself. The common shiner is, as usual, a nota-

ble exception, this abundant lake and river minnow being unusually

tolerant of polluted waters.

Starved Rock

The odor of the water at Stan'ed Rock, August, 191 1, was still dis-

agreeable, but there were no bubbles of gas from the bottom, and there

was sensibly less suspended matter in the water than at Marseilles.

North of the island the stream was perceptibly cleaner and of a

greener color than in the south channel, probably because it carried

a larger admixture of Fox River water, with its greener plankton.

The surface temperature of the water was 78° F. August 15, and

J2' August 26. The effect of Fox River contributions to the Illinois

was plainly manifest by an average difference of 21 per cent, between
the oxygen ratios of the two sides of the Illinois, as shown by
seventeen sets of tests made August 15 and 26, 191 1, and February

23, August 22, September 6 and 28, and October 11 and 26, 1912.

The lowest ratio of the series was 2.5 parts per million from the

south shore, September 6, 1912, and the highest was 5 parts per

million, also from the south shore, October 26. The general aver-

age for the south shore was 3.23 parts per millon (35.9 per cent, of

saturation), and that for the north shore, with its larger admixture

of Fox River water, was 3.91 parts per million (43.6 per cent, of

saturation).

The only sewage organisms found were isolated filaments or mi-

nute tufts of Sphccrotilns natans floating in the current. Minnows,
identified as golden shiners and spot-tailed minnows (Notropis hnd-

sonius) were seen swimming near the surface on both sides of the

river. This is the first observation of the second of these species.

An old resident of the town informed us that a considerable variety

of fishes is to be found here, practically at all times, but that the

numbers are never large.

In 1912, collections were made at Starved Rock September 3 and

9 and October 9 to 11. The water had still a slight sewage odor,

but less than at Ottawa. SpIiccrotilHs and Carchesinm were occa-

sionally seen attached to weeds and grass at the edge, and moderate



numbers of small particles composed of them were floating' down
stream. Samples of sludge obtained at this time were full of slime

worms, as usual, those from the chute on the north side of the island

averaging a hundred per plate, and those from the south side twice

as many. In the north chute were also many living snails, especially

Caiiipiiouia (which was very abundant) and a much smaller number
of Pliysa and Plcuroccra. The sludge collections from the south

shore contained some Campcloma, but none of the other snails. In

the channel below the island the current was too swift to permit the

deposit of a fine sediment, and the bottom was sandy, with dead

snails only. The only blue-green algje were a Lyngbya and a Plior-

iiiiditiiii, taken in three collections, while filamentous green algse oc-

curred in thirty-seven. The most abundant forms were Cladophora,

both crispata and glouicrata, and StigcoLioiiiiiiii tonic and hthricum.

Living sponges were obtained on dead mussel shells in three col-

lections.

The isopod Ascllits was common in dredge hauls and among the

algje at the edge. Crawfishes were taken here in two collections,

and Chirononius larvae and pupae in seventeen. The situation was not

productive of Unios, and but two species were taken alive

—

Ouadrula

plicata and Syniphynofa complanata. Five collections contained both

dead and living Sphcrr'uim trausvcrsuni, and four contained living

Ancylns. Statoblasts of Pluiiiatclla were alnindant in the drift, and

other Bryozoa were common on shells of dead and living mussels.

Our fishing at this point was mainly done September 3, between

Starved Rock and the mouth of the Vermilion. A quarter of a

mile below the landing, on the north shore, at the mouth of a creek,

a dynamite explosion gave us a blunt-nosed minnow, many shiners,

a Notropis jejumis, a large-mouthed black bass, and a gizzard-shad.

A half-mile below, dynamite and a 60-foot seine yielded a very large

number of shiners, three silverfins, a golden shiner, and a short-

headed red-horse (Moxostoma brcznccps). A haul of the 60-foot

seine on "Little Rock bar" near the south shore brought in several

hundred young carp from two to five inches long, a great abundance

of shiners, and a black bullhead. A haul in the channel with a

200-yard seine with an inch mesh, on the other hand, brought in no

fish. A dynamite explosion near the south shore, three quarters of

a mile above the mouth of the Vermilion, brought to the surface

three 2-pound carp and many shiners. Additional dynamite explo-

sions made September 3 and 4 at five different points down the river

as far as Spring Valley, gave us large numbers of the shiner

(Notropis atherinoides), but no other specimens except a 3-inch carp

and four golden shiners.



529

From the following complete list, compared with that made at

Ottawa, it seems that the fishes taken here represented the normal

river stock at this place, with practically no immediate admixture

from small tributary streams.

I Gizzard-shad (Dorosoina cepedianiim)

.

3 Carp, adults, and several hundred young.

I Short-headed red-horse (Mo.vostotna breznceps).

I Blunt-nosed minnow {Pimephales notatiis).

5 Golden shiner (Abraniis chrysoleiicas)

.

3 Silverfin (Notropis whipplii).

I Notropis jejunus.

Very many shiners {Notropis atherinoides)

.

I Black bullhead (Aineiunis jmlas).

I Large-mouthed black bass ( Microptenis saliiwides).

La Salle-Peru

In August, 191 1, the water at Peru had still a grayish look, was

full of very minute grayish particles, and had a slight sewage odor,

more pronounced near the northern side, partly, no doubt, because

of sewage entering the stream at La Salle and Peru. The presence

of Vermilion River water on the south side probably increased this

difference. The water temperature August 2, was 72° F. The only

collections made, besides those of fishes reported above, were mussels

obtained in 1912 by the use of the mussel-bar. Thirty-six specimens,

representing ten species, included twelve living specimens of five of

the species only, namely, Lampsilis data, L. liganientina, L. gracilis,

Quadrida plicata, and Syiiiphynota complanata. The large propor-

tion of dead specimens, as compared with the ratios obtained farther

down the stream, indicate unfavorable conditions for mussels in the

stretch of river between Utica and Peru. The following is a com-

plete species list.



530

Species



531

November 15, however, the oxygen ratios were precisely the same

—

8.9 for each. The loss of oxygen down stream in July was perhaps

due to a rapid hot-weather decomposition of sewage materials re-

ceived at Peru and La Salle.

Our only collections at Spring Valley were made with dip-nets,

dredges, and small seines October 15 to 18, 191 2. The water, even

this far down the stream, had a noticeable sewage odor and a grayish

color, with no tinge of green; but it improved greatly before reach-

ing Hennepin, where it was odorless and of a greenish hue. The
bottom sludge changes more slowly, however, as one goes down
stream, and samples taken October 18 a quarter of a mile below

Spring Valley in water twelve feet deep were still swamiing with

Tubifcx—several hundred to the plate. At Spring Valley the weeds

and grass at the edge of the river were free from Spharotiliis and
Carchcsiuni, and these sewage organisms were not taken . in the

plankton. No blue-green algje were found here except a small quan-

tity of Lyngbya versicolor; and the green filamentous algje were

mainly Cladoplwra crispata and Stigcoclonium tenue, with some
Ulothrix, Oscillaria, and Vaucheria. Sponges were found on the

mussel shells ; leeches occurred in eight of the collections ; Cyclops

was abundant in the algfe; and shells of five species of mussels were

dredged from the bottom—all dead, however, except one specimen

of Qitadrula pustulosa. Among the other living mollusks were many
Caiiipcloina, Planorbis trivolvis, Sphccrhnn transversum, Pisidiitm,

and Ancylus; and a few other species were represented by dead

shells. Pliiniatclla rcpcns was common on logs.

Depue

Similar collections were made October 17 and 18, 1912, from

the Illinois River, opposite Depue Lake. The sludge at this point

was less offensive than above, and contained but fifty specimens of

Tubifcx per plate. Three of the collections contained the isopod

crustacean Ascllus. Ostracoda were in the duckweed along shore,

together with the crustacean Hyalclla knickerbockeri, the first to

occur in these river collections below Lockport. Here also was taken

the first specimen of the common river shrimp, Palcnuonctes exilipcs.

Caddis-fly larvte were abundant on mussel shells, and dragon-fly

nvmphs were taken in five collections. Six species of mussels

—

Qitadrula hcros, Q. plicata, Q. pustulosa, Q, asperrima, Anodonta

grandis, and Tritogoiiia tubcrculata—were represented by living

specimens taken in a small dredge. Succinca, Campcloma, Planorbis,



532

Splucriuiii, Pisidiuiii, and Ancyclus were all abundant, as was also

I'lnniatella repens on sticks and logs.

In Depue Lake itself dip-nets, dredges, and small seines yielded

many common worms not found above, naiids, planarians, etc., and
Hyaldla knickerbockeri was abundant among algae, in all situations.

Insect larvas were likewise present in unusual variety, including

Chironomits and Ceratopogon larvae, larvae of caddis-flies and May-
flies {Ccenis and Callibcetis), tipulid larvae, and larvae of several

species of larger dragon-flies and damsel-flies {Agrionince). Among
the mollusks were Qiiadnila imdiilata, 0. plicata, Vhipara contec-

toides, Lioplax, Sphccriuin transversum, and Ancylus, htsid&s a num-
ber of species represented only by dead shells. Fishermen believe

that the poisonous wastes from the Depue zinc works are killing the

shells on the bottom of this lake. It was here that the first com-
mercial fisheries were encountered; and a haul made at the foot of

Depue Lake October i8, yielded about two hundred pounds of carp

and a hundred pounds of sunfish and crappies.

Hennepin to Henry

At Hennepin the water became to all appearance practically nor-

mal, even in the midsummer of 191 1, being odorless, greenish with

phytoplankton, and free from suspended clusters of foul-water or-

ganisms and particles of sewage debris. Here we found commercial

fiFliini^- in progress in bi5th the river and the adjacent lakes, mainly,

however, in the latter. Mud taken in September from the bottom

of the channel at Hennepin was more sandy than above, had no

offensive odor, contained many snails

—

Campeloma, Pleiirocera, etc.,

many specimens of Sphccriuin traiisi'ersiiiii, and only a moderate num-
ber of slime wonns. Similar materials were obtained from the bot-

tom at the Henry dam, except that the sediments in the sluggish

current there were softer, finer, and darker than in the full flow of

the stream at TItnnepin. At the low temperatures of March, 1913,

however, the sludge was offensively corrupt much farther down the

stream than in the warmer season, as will be more fully explained

under the next section. The midsummer microplankton of 191 1 con-

firmed the other lines of evidence, yielding but 2 septic organisms to

the cubic centimeter as compared with 16 at Starved Rock and 80

at Morris; and 6 pollutional forms as compared with 7 at Chilli-

cothe Ijelow, 71 at Starved Rock, 134 at Marseilles, and 142 at

Morris. Forms classed as contaminate, on the other hand, were

more numerous both here and at Chillicothe than above, and clean-



533

water forms were 138 to the cubic centimeter at Hennepin, 744 at

Chillicothe, and 154 at Marseilles, as compared with 193 at Morris.

Oxygen ratios were a little lower in July, August, and September

than at Starved Rock, and somewhat higher in October and No-
vember.

As this was the first station at which the life of the river may
be said to have found virtually normal conditions, some further

testimony to that effect may be drawn from our collections of mus-
sels and fishes. Seventeen species of mussels were collected alive,

and five others were represented only by dead shells. Of these

Lai)ipsilis fallaciosa, Oiiadnila pHcata, Symphynota complanata, Ano-
donta corptdcnta, and Quadritla heros were the most abundant, in

the order named, and, with a single exception, all the specimens of

these species were alive. The number of living shells as com-

pared with dead ones is in marked contrast to the conditions found

above. The following is a complete list.

Hennepin, 1912

Species



534

The following fishes were taken September 6 and 13 from the

river in the vicinity of Hennepin, by seven hauls of a 30-yard min-
now seine, 15 hauls with a 200-yard seine with an inch mesh, and
a single haul made for us by a fisherman with a common river-seine.

Hennepin, igi2

Short-nosed gar, i Speckled bullhead {Aineiiinis nebulo-

Dogfish, 3 sus), I.

Common sucker, i. Black bullhead, i.

European carp, 174. Black crappie (Ponioxis sparoides), i.

Shiner, many. Warmouth (ChcDwbryttus gulosiis), i.

Golden shiner, many. Blue-gill sunfish, 3.

The weather was very hot when the larger seines were used,

ranging above 90° F. every day, with the water at 79°, and the

fishing was unusually poor.

Henry to Chilucothe

As this is the final section of our series, a fairly full description

of conditions found and collections made will be desirable for com-
parison. Even under the midsummer conditions of July and August,

191 1, with the river temperatures at 73° to 80° P., the water had
a distinct greenish cast, without odor; and mud taken from the bot-

tom had a "good fresh smell." In March, 1913, however, the sludge

from a deposit two feet deep a hundred yai'ds above the Henry dam
had a distinct sewage odor, and was destitute of animal life, except

for one small leech, in nine two-quarts samples collected. The cooler

temperature of the water (41° F.) delayed decomposition, and the

comparatively strong current of the stream at the high water of

this visit (10 feet at the upper gage) was doubtless rolling the bot-

tom sediments more rapidly down the stream than in the lower stages

at which our earlier observations were made. Practically the same
may be said of the condition of the bottom mud from the main

channel at Chillicothe at this time. The river was, however, still

far below a normal unpolluted stream in oxygen ratios, and con-

tained much more carbon dioxide. A number of tests of midstream

samples made August 3 and August 29, gave us 2.33 parts per mil-

lion of oxygen as a minimum and 4.59 as a maximum, with an aver-

age of 3.76 for nine determinations. Carbon dioxide ratios for

this period ranged from 4.9 to 6.9 parts per million.

A heavy flooding rain which fell August 10 had the effect to



535

bring the oxygen ratios down, doubtless fouling the stream by flush-

ing out sewers, scouring out tributary streams, stirring up the bottom
sediments, and washing off organic debris from the surface of the

country. The oxygen mean for August 3 and 4 was 4.21, and that

for August 17 was 2.35, the corresponding carbon dioxide ratios

being 5.8 for the first dates and 6.8 for the last.

November 8, 191 1, the oxygen stood, at Chillicothe, at 10.15

parts per million, equal to 84 per cent, of saturation. Our lowest

reading at this place came in July, 1912, on the 12th of which month
there were but 2.05 parts per million of oxygen at Chillicothe—less

than 24 per cent, of saturation. In the cooler weather of the fol-

lowing October and early November, with moderately high water,

the ratios rose to an average of 7.5 parts per million (64 per cent,

of saturation).

Between Hennepin and Chillicothe the difference in dissolved

gases was but slight, and the plants and animals were virtually those

of the normal population at both places and on all our visits. Our
systematic collections here were made November 7, 191 1, Septem-
ber 18 and 19, 1912, and October 22-25 of the same year. As the

collections of the second year were much more detailed and exten-

sive than those of the first, no especial account of the latter need

be given.

September 18 and 19, the mussel-bar and dredges were used at

various points below Henry and above Chillicothe; and October 22-

25, work was done in the vicinity of Chillicothe only, with dip-nets,

dredges, and small seines, no large seines, set-nets, or dynamite be-

ing brought into use at these lower stations. The river gage above

the dam at Henry stood at 3.4 to 3.6.

Four hundred and ten collections were made from this section,

of which 159 contained mollusks, 91 contained adult insects and in-

sect lan'se, 42 contained Crustacea, and 18, fishes. Blue-green alga;

were found in 10 of the Chillicothe collections—chiefly Oscillatoria

liinosa and splciidida—usually, however, on boards and logs afloat

along the edge of the stream. Cladopliora crispata and glomerata
were the most abundant filamentous green algse, Stigeoclonmm tenue

and Spirogyra dccini'ma var. friplicata coming next. Duckweed
{Lemna and JVolffia), hornwort (Ceratophyllitui), and Blodea were
abundant higher plants. Sponges were found, as usual, on dead and
living mussel shells. Oligochjete worms were rare in the b6ttom
dredgings, as compared with those made alx)ve; planarians were
occasional, and leeches occurred in fifteen collections. Of the crusta-

ceans taken, the little "side .shrimp" (Hyalclla kiiickcrbockcri) was



536

the most abundant, among algje near the shores; Ascllns was also

common at the margin; and the river shrimp (Palcemonetes) and

crawfishes were frequently taken. The aquatic insects occurring

here were as follows

:

Adults: Gyrimis analis, Tropistcrnus dorsalis, T. glaber, Pelto-

dytes edentulus, P. pednncidatus, Coptotomus interrogatus, Dryops

lithophilus, Philhydrus ncbulosus, Colymbetes sculptilis, Notonecta

variabilis, Corixa erichsoni, C. buruicisteri; C. alternata, C. har-

risii, Mesovclia mulsanti, Zaitha flniiiinca, Pelocoris poeyi, Ranatra

fiisca. Larvas: agrionid nymphs, Mcsothemis siinplicicollis, Anax
Junius (nymph), Cclithemis nymphs, Odontomyia, Chironoinidcr,

caddis larvae, Chauliodcs.

Our mussel collections, representing twenty-two species, were very

like those at Hennepin, differing in the addition to the Hennepin

list of Lampsilis auodontoidcs, Obliquaria reflexa, Plagiola clegans,

P. sccuris, Quadrula cbena, Tritogonia tuberculata, and Unio gibbosus.

-Among the most abundant species were Anodonta imbecillis, Lamp-
silis fallaciosa, Quadrula hcros, and Q. plicata. Sphccrium transi'er-

suiii was also common here, with occasional specimens of S. stri-

atinuvi and S. jayanuin. Pisidium was taken in four collections with

the Ekmann dredge, in water six to eight feet deep.

The commonest snails were Cauipclouia and Vivipara contcctoidcs,

both very abundant in various situations, and Pleuroccra, obtained

mainly by the Ekmann dredge at depths varying from six to thirty

feet. Additional species are Physa gyrina, Plauorbis trivolvis, P.

parvus, Valvata bicarinata, Lioplax, Goniobasis, and Amnicola.

Commercial fishing is carried on in the Henry-Chillicothe sec-

tion on a large scale in good seasons, but much complaint has lately

been made, all along this part of the river, that fishing is not so

good as in former years. No systematic work for the collection

of fishes was done, and the only specimens taken were caught in

small seines used for collecting shore invertebrates, and are as follows :

Golden shiner, i. Fundulus dispar, 8.

Spot-tailed minnow, 3. Warmouth sunfish, i.

Silverfin, i Blue-gill sunfish, 7.

Shiner, 61 Large-mouth black bass, 2.

Top-minnows (young), 2. Yellow perch, i.

This list should be combined with the list for Hennepin to give

a fair idea of our collections from this section of the river at this

time, those from Hennepin having been made wholly with large

seines.



537

We have secured further information concerning the present sta-

tus of the more important fishes in this part of the upper IlHnois

by incjuiry from rehable, experienced, and unusually well-informed

fishermen of our acquaintance, especially from Herman Mehl and

A. C. Wilkey, of Chillicothe, Peterman Brothers and Herbert Hall,

of Henry, and F. L. Powers, for twenty-seven years a fisherman at

Depue, and the following list is made up from their personal state-

ments to us.

STATUS OF Principai, Fishes, Upper Illinois River,

Chillicothe, Henry, and Depue, April, 1913

(Statements as to numbers relate to the river only, except whore otherwise specified)

Fishes Chillicothe Henry Depue

Shovel-nosed sturgeon

Paddle-fish

Dogfish

Short-nosed gar

Long-nosed gar

Mud-cat

Channel-cat
(htalurus punctatus)

Blue cat

(Ictalurus furcatus)

Bullhead; 3 species

Never taken now

Very few ; none this

year

About as numerous as

ever

As numerous as ever

As numerous as ever

Very rare

Becoming scarce

None at all

About as formerly

Common sucker

Missouri sucker

Red-horse (Mo.vosfoma,
various species)

Native carp (Carpiodes;
various species)

Very few

Hardly ever seen

Very rare

Not many

Never taken now

Very few ; none this

year

iecoming scarcer

As numerous as ever

As numerous as ever

None

Becoming scarce

Very rare or none

Not so many as formerly

Not many

One this spring

Very rare

Not many

None seen for years.

None seen for 6 or 7

years past.

Few.

Common, but less nu-
merous than formerly.

Common, but less nu-
merous than formerly.

None.

Now rare; 15 years ago
were taken by the ton.

None taken for years.

Much less common than

formerly
;
yellow bull-

head now most abun-
dant.

None at all.

None at all.

Gone entirely ; taken by
the ton 15 or 20 years

ago.

Only a few.



538

STATUS OF Principal Fishes, Upper Illinois 'Rivn^— Continued

Fishes



539

It should be said, with respect to the present scarcity of several

of these species as compared with previous times, that the causes

are probably complex, and are not to be sought in differences of

the water only. As has been shown in another place*, a great stimu-

lus to fishing operations, due to an enormous multiplication of Euro-

pean carp, may well have had the effect to reduce the numbers of

many native species whose haunts and habits are such that they are

likely to be caught by the same apparatus and operations as the carp.

A comparison of this account of Chillicothe conditions and col-

lections with those for Morris and for Marseilles above the dam will

show the main features of the effects of a sewage pollution of the

river and the completeness of the biological, if not the chemical,

recovery within ninety miles below.

Summary by Stations

The Sanitary Canal at Lockport.—Although the water of the

canal at Lockport was comparatively clear, with an inoffensive odor
even in August and September, 191 1, it was not only rather heavily

loaded with putrescible materials from Chicago sewage, mainly as

yet undecomposed, but it was lower in oxygen content at most times

than the river water either of the Des Plaines or the Illinois at any
point where our tests and collections were made. In the winter

however, the amount of oxygen in solution approximated the ratios

of an unpolluted stream, l^eing actually higher in February, 19 12,

than at any point between Lockport and Peoria. This is to be un-

derstood, of course, as due to the gradual start and slow develop-

ment of the self-purification process in cold weather. Many small

fishes came down the canal in summer and fall, mostly dead when
they reached Lockport, although many "shiners" were still alive, but

in a dying state. There were no living snails, crustaceans, or water-

breathing insects in the water or on the bottom, and except for a

few green alg?e and other minute organisms on the riprap at the

edges, the plants and animals were those of a polluted stream. These
were, however, very much less abundant here in summer than in the

Des Plaines beside the canal, or in the main river Ijelow.

The Des Plaines River at Lockport.—The condition and contents

of the Des Plaines at Lockport, where the stream runs beside the

sanitary canal, vary greatly with varying circumstances—local, sea-

sonal, or merely meteorological. In the summer of 1911, the whole

*"The Native Animal Resources of the State." Steplieii A. Forlies. Trans.
Fifth /\nn. Meeting. 111. State Acad. Sci.. pp. 42-43.



540

stream at this point was carrying polluted water, and sewage or-

ganisms were abundant across the bottom and on both sides— a fact

to be attributed in part, according to our best information, to con-

tributions of sewage from the towns above. In August and Septem-

ber, 1912, however, the two sides of the Des Plaines were in marked
contrast. On the west side were minnows, sunfishes, green algae,

' case-worms, sand-fly larvje, Bntoiiiostraca, Hyalella knickerbockcri,

and several kinds of moUusks, while on the east side Sphcerotilus,

Carchcsiiiin, Vorticella microstouia, and numerous other sewage or-

ganisms predominated, with fishes and clean-water mollusks con-

spicuous by their absence.

The Des Plaines River at Dresden Heights.—The Des Plaines at

its mouth was heavily loaded with putrescible sewage materials so

far advanced in decomposition that oxygen ratios were always very

low. They differed however, according to season, in comparison with

those of the next lower stations, being higher than these in the

hottest weather and lower at lower temperatures. In July, 191 1, for

example, when the water of the Des Plaines contained 1.21 parts per

million, that of the Illinois stood at 1.07 at Morris, and at .83 above

the Marseilles dam. In November, 19 12, on the other hand, the

corresponding figures were 4.90 for the Des Plaines, 6.80 for the

Illinois at Morris, and 7.90 at the Marseilles dam. This seasonal

difference is again to be accounted for by the different effect of low

and high temperatures upon the beginning and rapidity of the de-

composition process in a polluted stream.

The plants and animals of the Des Plaines being of a diverse

origin, were a mixture of clean-water forms from the lake and from
the upper river which had not yet been overcome by their septic

environment, and of species characteristic of polluted water, the

latter group strongly dominating. Saprobic organisms of the mid-

summer microplankton were more numerous here than at any point

on the river ; but mingled with these were many Lake Michigan dia-

toms, some of which presently disappeared down stream, two con-

tinuing, however, to the lower river, where they became very abun-

dant beyond the heavily polluted section.

There were no fishes, mollusks, crustaceans, or insect larvje (ex-

cept Chironomus) in the Des Plaines at Dresden Heights, although

the Kankakee, but a few rods away, contained the usual biological

population of a normal Illinois river.

The Kankakee at its Month.—Notwithstanding the fact that the

Kankakee can hardly be called an uncontaniinated river, its contrast

with the Des Plaines, especially in summer, was very marked. When



541

the water of the latter stream at its mouth contained but 1.21 parts

of oxygen per million, the ratio for the Kankakee was 11. 21; and

when the oxygen in the Des Plaines rose to 4.90 in November, that

of the Kankakee was 10.90. Our lowest reading for the latter stream

was 9 parts per million, in February, when the Kankakee was mainly

covered with ice. Most of the oxygen ratios in the Kankakee were

above those which the water will absorb directly from the air, and

indicated a "supersaturation" varying from 105 to 133 per cent.

The diiTerences between the two waters thrown together at the

origin of the Illinois were reflected in oxygen ratios from the two

sides of the stream just below the junction, as reported November

14, 1 91 2—4.6 parts per million for the water of the northern or

Des Plaines side, and 11.3 parts per million for the water of the

southern or Kankakee side.

Morris to Marseilles.—In the seventeen-mile section of the Illi-

nois from Morris to the upper dam the river reaches its lowest point

of pollutional distress, becoming, when very hot weather coincides

with a low stage of water, a thoroughly sick stream. Its oxygen is

nearly all gone ; its carbon dioxide rises to the maximum ; its sedi-

ments become substantially like the sludge of a septic tank; its sur-

face bubbles with the gases of decomposition escaping from sludge

banks on its bottom ; its odor is offensive ; and its color is gray with

suspended specks and larger clusters of sewage organisms carried

down from the stony floor of the polluted Des Plaines, or swept from

their attachments along the banks of the Illinois. On its surface are

also floating masses of decaying debris borne up by the gases de-

veloping within them, and covered and fringed with the "sewage

fungus" {Sphccrotiliis natans) and the bell animalcule ( Carchesimn

lachinanni) usually associated in these waters. The vegetation and

drift at the edge of the stream are also everywhere slimy with these

foul-water plants and minute filth-loving animals. The two sides

of the stream differ materially in condition at Morris, and sometimes

also at Marseilles, the waters of the Kankakee and the Des Plaines

not becoming completely mingled until they have passed these points.

The normal life of the stream practically disappears in the al>

sence of oxygen ; its fishes withdraw to neighboring unpolluted

waters; its mollusks, crustaceans, ordinary insect larvae and other

more or less sedentary forms disappear to be replaced mainly by

slime worms and Chironomus larvre in the sludge; and its chloro-

phyll-l>earing plants linger only along the edges in shallow water. With

the advent of cooler weather and higher river levels, most of these

marked symptoms disappear, and a fev/ fishes may even make their



542

way into the stream, particularly along the south side in the vicinity

of the mouths of creeks. In spring and in fall, bubbling from the

bottom ceases, the odor of the water is no longer repellent, a few
invertebrate animals reappear, and the oxygen ratios rise to a con-

siderable fraction of those normal to the Kankakee. The extent of

this seasonal oscillation depends, of course, upon the rainfall and
temperature; and the opposite extreme is reached in winter, when
midstream oxygen ratios may be fully as high as those of the summer
time for Chillicothe and Peoria.

The Marseilles Dam.—The waters of the stream change but little

between Morris and the Marseilles dam, the oxygen content being

sometimes a little higher at one point and sometimes at the other.

The mean of eight sets of determinations in six different months was

4.5 parts per million for Morris and 4.3 at Marseilles above the dam.
The water is usually somewhat freer of sewage organisms at Alar-

seilles than at Morris. This is evidently owing in part to sedimenta-

tion of suspended particles, especially the larger ones, in the slack-

water above the dam, where the current, even at flood stages, was
only about half a mile an hour. Both plants and animals are a little

more varied and abundant at Marseilles in sheltered pockets along

the banks; and a larger variety of fishes was obtained at the edge

of the river close to the mouths of creeks.

The interesting feature of the Marseilles situation is the effect

produced by the fall over the dam* at low water. In samples taken

far enough below the fall to give the air caught in the water ample
opportunity to escape, we found the ratios of dissolved oxygen in

July and August, 191 1, more than three times as great as those above,

from one and a half to two times as great in August and September,

1 91 2, when the water was cooler and the river higher than in the

midsummer of the previous year, and 13 to 14 per cent, greater

under winter conditions in February and March. This difference in

oxygen doubtless had its effect upon the abundance of fishes, al-

though these might well be expected to be more numerous below

the dam than above, even if the oxygen supply were the same. The
fish population was, however, small and scanty, if we may judge by

our collections, consisting mainly of carp, bullheads, and the ever-

present shiner in the main stream, with a considerable variety of

species in shallow water near the mouths of tributaries. Black bass

were reported to us to come up to the dam only in the highest water.

Ottazva and Starved Rock.—At Ottawa and Starved Rock a con-

*This dam is about 710 feet in length, and its height is about ten feet above

the rock-bed of the river. (E. H. Heilbron, in letter.)



543

siderable progressive improvement of river conditions was manifest,

due to sedimentation, to self-purification, and to dilution with cleaner

tributary waters. Oxygenation increased between Marseilles below

the dam and Starved Rock by 36 per cent, in August and by 14 per

cent, in September, but in February it was the same at these two

stations. Other evidences of sewage contamination were similarly

diminished—the color of the water, the number of foul-water or-

ganisms either suspended in the water or growing at the edges, the

scarcity and small variety of fishes resorting to the middle of the

stream—until at Starved Rock we got our first somewhat represen-

tative collections of distinctly main-stream fishes—gizzard-shad, red-

horse, carp, bullheads, and black bass. Although the slack-water

sludges were scarcely changed in character from those farther up the

stream, living mussels began to appear in this section in small variety,

but mainly in the cleaner water of the Fox; decapod and isopod

crustaceans (crawfishes and Asellus) came in here in some numbers;

and sponges and Bryozoa put in an appearance in especially favorable

spots. The contaminational blue-green algse, common along shore

above, practically vanished ; and the chlorophyll-greens changed from

Stigcoclonium tcnue as the dominant form to species of Cladophora,

significant of cleaner water. The degrees of this improvement va-

ried, of course, as usual, with the temperature and the stage of water.

Spring Valley.—It was at Spring Valley, fifty-seven miles below

the mouth of the Des Plaines, that, in summer time, the last visible

symptoms of water pollution were to be seen. The water here had

not yet recovered its normal slightly greenish tint, but was still

grayish with suspended specks of septic and pollutional plankton;

and it still smelled slightly of sewage, in part no doubt because of

local contamination from Peru and La Salle, a few miles above. It

was here that the little amphipod crustacean, Hyalclla knickerbockcri,

made its first appearance below the Kankakee, and here that the

first specimens of the river shrimp, Palcemonetes exilipes, were col-

lected. A considerable variety of aquatic insect larvje, of living mus-

sels, and of gastropod mollusks, and a much smaller proportion of

dead shells, testified further to an improved environment. This was
also the first place on the river in which commercial fishing opera-

tions were being carried on at any time.

These biological tests were more favorable to the Spring Valley

situation than the chemical ; but they are, on the whole, more reli-

able, if they are used with intelligence and discretion, because they

show the accumulated general consequences of local conditions, favor-

able and unfavorable, while the chemical determination applies only



544

to the moment and to the place of the collection of the sample tested.

Hennephi to Henry.—At Hennepin it may be fairly said that vir-

tually normal conditions were found, except for the state of the bot-

tom in winter time ; although it must be confessed that our chemical

data, especially those for the midsummer low-water of 191 1, were
hardly consistent with this statement. Only 22 to 28 per cent, of

oxygen saturation, with carbon dioxide running up to 7.5 parts per

million, are ratios very far from those normal to an uncontaminated
stream; and the highest oxygen ratio found here at any time was 82
per cent, of saturation in November. Nevertheless, the greenish

tint of the water caused by the chlorophyll-bearing plankton, the vir-

tually complete disappearance of septic and pollutional organisms,

the inoffensive odor of the bottom sediments, except in winter, the

great predominance of living over dead specimens of the twenty-two
species of mussels taken here, and the appearance, even in hot sum-
mer weather, of suckers, crappie, warmouth, and blue-gill sunfish

in the products of our seines, showed that biological tests must be

added to those of chemical analysis if we are to have a fair picture

of the stages of recovery in a heavily polluted stream.

Henry to Chillicothe.—In this, the last section of the upper Illi-

nois systematically studied by us in 191 1 and 1912, the process of

renovation is simply carried a little farther on than in the Henr\'-

to-Hennepin section just above. It is only in the winter time that

the effects of pollution are manifest here to the senses, in the more
or less rank and repellent odor of the sediments at the Henry dam,
and even of those from the bottom of the open channel at Chilli-

cothe ; and it is perhaps in part to this condition that we must attrib-

ute the reported great reduction in numbers of large catfish and of

buffalo from this part of the stream.

There are, indeed, many species of fishes, most of them charac-

teristic bottom- feeders, which were formerly common in the upper

part of the Illinois River, taken in quantity there by fishermen sev-

eral years ago, but which are now either wanting, rare, or greatly

reduced in numbers. The large catfishes, the red-horse, the buffalo,

and the sheepshead are examples ; and even the bullheads are said

to be less common at Henry and Depue than in former years. On
the other hand, the sunfishes, crappies, and bass are likewise reported

to be decreasing of recent years, at least at Henry and Depue. In-

deed, the reported recent reduction in numbers of the more abundant

food fishes clearly becomes more pronounced as we go up stream

from Chillicothe to Depue, although fishing operations are less active

northward—a fact which points to unfavorable river conditions as

a probable cause of this diminished yield.



545

General Summary of Chemical Features

The foregoing general discussion of the assemblage of conditions,

chemical and biological, found at each of our observing stations in

succession for the entire period of our observations, may well be

supplemented by a separate recapitulation of the more important

chemical features of the river situation made to include oxygen de-

terminations from the middle and lower Illinois as well as from the

upper part of the stream, and from the Mississippi near its mouth

—

a form of discussion which will bring out a few conclusions not

easily arrived at in any other way.

July and August, ipji.—The lowest ratios of dissolved oxygen
in the upper Illinois were found in July and August, 191 1. When
determinations at the mouth of the Kankakee varied but little from
10 parts per million, those from the midstream at Morris, nine miles

below, ranged from .24 to 1.78; at Marseilles, above the dam, seven

miles farther down, they averaged .67, and below the dam 2.18; and
at Starved Rock, 3.18. At Chillicothe the ratios varied on different

days from 2.10 to 4.21 parts per millon, with an average of 3.47.

Single determinations at this lowest of our river stations yielded as

little as 19.5 per cent, of saturation, and the average of all our mid-
summer determinations here for 191 1 was but 40.8. As the Kan-
kakee River average at this time was 112.2, it appears that during

the upper ninety-three miles of its course the Illinois did not regain

much more than a third of the oxygen lost to the Chicago sewage.

Heavy general rains from the loth to the 12th in the upper Illi-

nois basin disturbed river conditions materially, bringing the Kan-
kakee up about six inches at its mouth and the Illinois eight inches

at Marseilles and raising the levels below. Our trips for collections

and chemical analyses were made on three rounds from Dresden
Heights to Chillicothe, the first ending a week before these rains be-

gan, the second beginning at Dresden Heights on the date of the

principal rainfall, and the third following ten days after the rains

were over. Our oxygen tests are comparable for these trips at the

following five points : Dresden Heights, Morris, Marseilles above

the dam, Marseilles below the dam, and Chillicothe. At all these

places except Morris the oxygen ratios were considerably lower after

the rain than before, the decline being greatest (50 per cent.) at

Chillicothe, nearly a week after the rains. Averaging the readings

for these five points on the three successive trips, we got the same
mean oxygen ratio, of 3.64, for both the first and the last trips, and

3.17 for the intermediate one, indicating a decline of 13 per cent, in



546

the oxygen of the river water after the rains, followed presently by
a return to the original mean.

This effect is graphically illustrated by Figure 2, Rate LXXX,
where two of the lines, representing the first and last trips, run
closely parallel from Marseilles onward, while the line for the inter-

mediate trip diverges from the others to an increasing degree from
Marseilles to Chillicothe. These interesting facts may be taken as

suggestive of a general fouling of the water of the stream by heavy
midsummer rains coming after a long period of heat and of dry
weather. A general flooding and scouring of the surface of the

country, washing off of the streets of towns, and flushing out of

sewers, caused by heavy rains, may be supposed to bring into the

river water containing larger ratios of organic matter than the

stream itself; and to these we must probably add the stirring up
and carrying off of the largely organic bottom sediments of the main
river.

The carbon dioxide ratios in July and August, 191 1, varied from
none to 2.1 for the Kankakee River, and rose as high as 12.8 at the

mouth of the Des Plaines and ii.i at Morris and Marseilles. The
Illinois River ratios were lowest at Chillicothe, where, however, the

mean for the three sets of detemiinations, August 3, 17, and 29, was
6.3 parts per million. This is to be compared with a mean of .8 for

the Kankakee River for the same period.

September, ipii.—During the second week in September, 191 T,

when the oxygen in the midstream at Morris averaged .59 parts per

million and that of the Illinois just above the outlet of Depue Lake,

near Hennepin, stood at 2.65, waters from the middle of Depue Lake
itself contained 11.78 parts per million, equivalent to 42 per cent,

above the saturation point at the prevailing temperature of the lake

water. Even the Illinois and Michigan Canal at Morris, considerably

contaminated with Chicago sewage as it is, contained at this time

6.8 parts per million of oxygen when the waters of the Illinois River

gave 2.03 for the south or Kankakee side, and .88 for the north

bank, or Des Plaines water.

November, igii.—The effect of a higher temperature and higher

water levels was clearly shown in November, 191 1, by the much
higher oxygen ratio at all points on the upper Illinois. The river,

having lately fallen about three feet, was still, at this time, some
two feet higher than in the preceding July and August, and the

temperature of the water had declined from 72.5° F., the mean of

our midsummer readings, to 46°, the mean for November i to 8

(8:30—9 a.m.). The following is a table of parts per million of

oxygen at the points where comparable tests were made.



547

Des Plaines River
Morris
Marseilles
Hennepin
Chillicothe

Mid-
summer
1911

1.21
1.15
.67

2.85
3.47

Nov. 1-8

1911

4.7
4.6
9.9
9.8
9.8

This is an average increase of 5.7 parts per million, or ot

300 per cent., of November over midsummer ratios for this part of

the Illinois River.

February and March, 1912.—A trip was made for chemical deter-

minations February i to 8, 191 2, from Lockport to Chillicothe, and
another, March 18 to 28, from Lockport to the mouth of the Illinois

at Grafton. The water temperatures averaged 34° F. on the first

trip, and 35° on the second, the upper river being quite frozen over

much of the time.

The oxygen detenninations of these trips differ widely from those

of the preceding midsummer in the much higher ratios found in the

winter and in the fact that the lowest point for oxygen was very
much farther down the stream. In all our midsummer trips this

lowest point was reached at the Marseilles dam, but in February there

was less oxygen at Chillicothe than at Marseilles, and in March,
when the whole length of the river was traversed, the oxygen ratios

declined down stream from Marseilles to Havana, rising then grad-

ually to the mouth of the Illinois. At Morris the ratio of oxygen
was more than six times as great in February as in midsummer;
above the dam at Marseilles it was more than eight times as great;

below the dam more than three times; and at Chillicothe it was 30
per cent, greater. The March ratios from Morris down were much
higher still, reaching a maximum of 10 parts per million below the

Marseilles dam, falling thence rapidly to Peoria (6.8), dropping a

trifle only at Peoria below the outlets of the sewer system (6.5),
declining slightly to Havana (6.2), and then rising steadily to the

mouth of the Illinois (9.4), the water of the Mississippi standing at

the same time at 10.5. In the entire distance from Lockport to

Grafton the percentage of oxygen saturation on this March trip did

not fall below 44 (Peru), nor rise a1x)ve 75 (south shore at Morris).

July, I()I2.—A single trip was made July 11 to 15, 1912, in

company with the chemists of the Sanitary District of Chicago, com-
mencing, unfortunately for our purposes, at Peru, and giving us no



548

data, consequently, for the interesting section of the river above

Marseilles. As this trip extended to the mouth of the Illinois, it

can be used from Chillicothe downward as an extension of the

midsummer trips of the preceding year, which stopped at that point,

to give us an idea of midsummer conditions for the whole stream.

It is mainly interesting as showing an irregular but gradual rise in

oxygen ratios from Chillicothe to the Mississippi, from 2 parts per

million at the former place to 4.7 at Twelve-mile island, thirteen miles

above the junction of the Illinois with the Mississippi. A cross-

section of the latter river at Grafton, below the junction, gave 4.85

parts per million on the Illinois shore below the mouth of the Illi-

nois River, of 7.15 at the middle of the Mississippi, and of 7.65 on

the Missouri side beyond the reach of Illinois River water. Other-

wise stated, while the oxygen of the water of the Illinois near its

mouth lacked in July 39.5 per cent, of saturation, that of the un-

diluted Mississippi lacked only 1.5 per cent. The residual effect of

the contamination of the former stream was thus a final loss of 38
per cent, of its oxygen.

August to October, ipi2.—Our chemist made in August, Septem-

ber, and October, 1912, only short visits to the river to determine

the oxygen ratios where biological collections were in progress, and

his data are consequently in fragmentary series only. Four tests

made August 21 and 22 at Marseilles, Ottaw^a, and Starved Rock
are of interest for comparison with those made at Marseilles and
Starved Rock August 24 to 26, 191 1, as shown by the following

table.

Marseilles (above dam)
" (below dam)

Ottawa
Starved Rock

1911

.44

2.26

3.43

1912

1.90
2.90
3. 65
4.05

The mean of the water temperatures for the 191 1 period was
70.5° F., and that for August, 1912, was 6° lower; and the river

levels at Morris stood some six feet higher in August, 191 2, than in

August, 1911. These differences of conditions are fairly reflected

in the virtual doubling up of the oxygen ratios in 19 12 at the con-

trasted points.

November, igi2.—For November, 191 2, we have two trips, a

fortnight apart, made the entire distance from Lockport to the



549

Mississippi River. The data thus obtained resemble each other closely

in the general trend of the series of determinations, from a very low

ratio at Lockport, with a considerable and rather steady rise to Peo-

ria (10.5 parts per million), and nearly uniform ratios thence to

the mouth of the Illinois. The later series, of November 12 to 19,

runs on an average considerably higher than the earlier, November
I to 7, but notwithstanding the saturation percentage of 87 at the

mouth of the river (10.7 parts per million) it presents the strongest

contrast with the Mississippi River, the midstream waters of which
contained at this time 14.2 parts per million, amounting to 114 per

cent, of saturation. There was no place on the Illinois on either of

these trips where the oxygen ratios were less than 4.6 parts per

million.

THE EFFECT OF A D.\M ON DISSOLVED G.-^SES

The fall over the Marseilles dam in the hot weather and low-water

period of July and August, 191 1, had the effect to increase the dis-

solved o.xygen more than four and a half times, raising it from an

average of .64 parts per million to 2.94 parts. On the other hand,

with the cold weather, high oxygen ratios, and higher water levels

of February and March, 191 2, and the consecpient reduced fall of a

larger volume of water at Marseilles, the o.xygen increase was only

18 per cent.—from 7.35 parts per million above the dam to 8.65

parts below; and in August and September, 1912, the weather being

still cooler and the water lower than in the midsummer of the pre-

vious year, the increase was only "]"] per cent.—from 2.05 parts per

million above the dam to 3.62 parts below. It should be noted, how-
ever, that this beneficial effect is greatest when it is most needed

—

when the pollution is most concentrated and decomposition processes

are most active. In the absence of a dam at this point, the recovery

of oxygen used up in decomposition would be greatly retarded in

midsummer, and heavily polluted water would be carried much
farther down the stream.

A reverse but much less pronounced effect is produced at the dam
upon the carbon dioxide content of the waters of the stream. This

was diminished, in the summer of 191 1, from 8.2 parts per million

above to 6.48 parts below the dam—a reduction of 21 per cent. The
ratio of loss of carbon dioxide was thus only a seventeenth part of

the ratio of gain in oxygen. A similar statement may be made con-

cerning losses and gains of these gases for the upper Illinois River

as a whole. Taking the means of the oxygen ratios at each point for

the period from July 28 to .August 29, 191 1, we find them rising



550

from 1.35 at Morris to 3.82 at Chillicothe—an increase of 183 per

cent.; while the carbon dioxide drops from y."] to 6.1, a loss of 22
per cent.—the greater part of l^oth changes occurring, in fact, at the

Marseilles dam. It will thus be seen that in judging of the biological

effects of pollution and self-purification of the stream, we must take

note of the fact that a given increase or decrease in carbon dioxide

is accompanied by a loss or gain in oxygen from eight to seventeen

times as great.

SEASONAI, PHASES OF CHEMICAL CONDITIOISr

The combination of our tables and our graphs by seasons, and a

comparison of these sets of seasonal data one with another, brings

out clearly three phases in river condition which may be called the

midsummer, fall, and winter phases, and implies also a fourth or

spring phase, for which we have at present no data. The midsum-
mer and the winter phases represent, of course, the extremes between
which the fall and spring conditions come as intermediate or transi-

tion stages. The midsummer phase, with its high temperatures and
low stage of water, is characterized by a concentrated pollution and
an early and rapid decomposition and deoxygenating process, with

lowest oxygen readings at Morris and above the dam at Marseilles,

followed by a sudden increase of oxygen below the dam and a

gradual rise in ratios thence down the stream to its mouth. The
winter phase contrasts with this by a delay of decomposition such

that the oxygen ratio is highest at Marseilles, declines slowly to the

middle of the river's course, (about at Havana,) and then rises

gradually to its mouth. In the autumnal transition phase the oxygen
ratio is at its lowest point in the Dresden Heights-Marseilles sec-

tion, although much higher there than in midsummer, rises thence

slowly to Peoria, and continues on an approximately level line to the

mouth of the Illinois. In the spring phase a transition in the oppo-

site direction probably gives somewhat similar results, modified, how-
ever, by the spring floods, which are usually much larger than those

resulting from the fall rains, and by differences in the antecedent

seasonal conditions from which this spring transition makes its start.

These periodical changes in the distribution of oxygen and car-

bon dioxide within the stream are, of course, consequent upon sea-

sonal differences in temperature and stage of water, influenced con-

siderably by the upper dam, at Marseilles ; and tlie above descriptions

may perhaps need modification to make them apjilicable to notably

unusual j^ears.



551

ADDITIONAL DATA UPON THE RIVER SLUDGES

Since this manuscript was prepared we have recei\'ed from tlie

chemists of the Water Survey a report on the following series of nine

sludge samples collected in March, 191 3, with a view to detemiining

the winter condition of the ri\-er sediments throughout the length of

the stream. It will be seen that they agree in the main with the short

series on page 00 to the effect that a marked change occurs between

Marseilles and Henry, and that they show a gradual improvement in

respect to organic contents in the samples obtained below Peoria.



552



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573

EXPLANATION OF PLATES

Plate LXV
Upper Illinois River and principal tributaries.

Plate LXV I

Fig. I. Des Plaines River and Sanitarj- Canal at Lockport
Fig. 2. Illinois River at Marseilles.

ERRATA

Page 497, line g from bottom, for ncglibte read negligible, and in footnote,

for Austalt read Anstalt.

Page 498, line 4 from bottom, for Lockftort read Chillicothe.

Page 500. line 13 from bottom, after »/> insert in.

Page SOI, line 2 from bottom, for dissolving read dissolved.

Page 504, line 23, for gryina read gyrina.

Page 506, line 11, for vernata read ternata.

Page 507, line 3 from bottom, for Ma::on read uagon.

Page S13, line 19, for Net>a read Zaitha.

Page 525, line 22, and page 536, lines 21 and 24, for Ekmann read Ekman.

Page 532, line i, for Ancyclus read Ancylus.

Page 551, line 7, for 00 read 512.

Plate LXXXV, for 7 read 7c.

Plate LXXVII
View of Flag Lake, 1910.

Plate LXXVIII
Permanent overflow of Illinois River bottoms near Havana,

Plate LXXIX
Characteristic views from the middle course of tlic Illinois.



572

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EXPLANATION OF PLATES

Plate LXV
Upper Illinois River and principal tributaries.

Plate LXVI
Fig. I. Des Plaines River and Sanitary Canal at Lockport
Fig. 2. Illinois River at Marseilles.

Plate LXVII
Illinois River at Morris.

Plate LXVIII

Marseilles Dam, June 15. 1901. View from north end.

Plate LXIX

Marseilles Dam, July 22, 1906. View from south end.

Plate LXX
South bank of Illinois River, below Ottawa.

Pl.\te LXXI

In Horse-shoe Caiion, near Ottawa.

Plate LXXII

Illinois River bluff, immediately above Starved Rock.

Plate LXXIII

The Valley of the Illinois, from Starved Rock.

Plate LXXIV
The Valley of the Illinois, from Prospect Heights, above Peoria.

Plate LXXV
Sketch of waters near Havana, 191 1.

Plate LXXVI
The Illinois River and bottom-land lakes, from Havana, lOlo.

Plate LXXVII

View of Flag Lake, 1910.

Plate LXXVIII

Permanent overflow of Illinois River bottoms near Havana.

Pl.\te LXXIX
Characteristic views from the middle course of tlie Illinois.



574 ,

Plate LXXX
Fig. I. Illinois River levels, Havana. Monthly means, 1897-98 and 1909-10.

Fig. 2. Dissolved oxygen, Kankakee, upper Illinois, and Des Plaines rivers,

midsummer of 1911.

Plate LXXXI

Fig. I. Dissolved oxygen Illinois River. November data.

Fig. 2. Dissolved oxygen, Illinois River. Winter and midsummer data.

Plate LXXXII

Fig. I. Eristclis tenax. after Miall.

Fig. 2a-2C. Hyalclla knickerbockcri: 2a, entire animal; 2b, first cheliped ; 2C,

first"uropod ; 2d. second uropod; 2c, telson, (U. S. Geol. and Geogr.

Surv. of the Territories, 1873.)

Fig. 3. Slime worms, Tiibifcx, after Kolkwitz.

Fig. 4. Rotifer actinurus, after Kolkwitz.

Fig. 5. Colpidium colfioda, after Kolkwitz.

Fig. 6, Paramecium Putrinum, after Kolkwitz.

Plate LXXXIII

Fig. I. Paramecium candatum, after Blochman.

Fig. 2. I'orticella microstoma, after Blochman.

Fig. 3. Epistylis plicaiilis, after Blochman.

Fig. 4. Carchesinm lachmanni, after Kent.

Fig. S. Anihophysa vegetans, after Blochman.

Fig. 6. Anihophysa vegetans, after Kent.

Fig. 7. Chlaniydoinonas monadina. after Blochman.

Fig. 8. Oikomonas termo, after Blochman.
Fig. 9. Bodo saltans, after Kolkwitz.

Fig. 10. Stigeoclonium tenue, after Kirchner.

Plate LXXXIV

Fig. I. Chatophora elcgans.

Fig. 2. Microthamnion kiitzingianum, after Kirchner.

Fig. 3. Cladophora crispata, after Kolkwitz.

Fig. 4. Cladophora glomerata, after Kolkwitz.

Fig. 5. Schinomeris leibleinii. Tufts College Studies. Vol. II.

Fig. 6. Ulothrix sonata.

Fig. ya-ye. Chlorella vulgaris. Rev. Gen. Botanique, Tome XV. .

Fig. 8. Lyngbya versicolor. Minn. AlgK, Vol. I.

Fig. 9. Phormidium uncinatum. Minn. Algse, Vol. I.

Fig. 10. Oscillatoria liinosa, after Kolkwitz.

Plate LXXXV
Fig. I. Cyclotella klitzingiana, after Kirchner.

Fig. 2. Fragilaria virescens. after Kirchner.

Fig. 3. Tabellaria Aoccnlosa, after Kolkwitz.

Fig. 4. Tabellaria fcnestrata. after Kirchner.

Fig. 5. Mclosira various, after Kolkwitz.

Fig. 6(7, 6b. Spharotilus natans, after Kolkwitz.

Fig. 7a, yc. Cladothrix dichotoma. after Kolkwitz.

Fig. yb. Cladothrix dichtoma, after Kirchner.

Fig. 8. Beggiatoa alba, after Kolkwitz.



Plate LXV

UPPER ILLINOIS RIVER AND
PRINCIPAL TRIBUTARIES

SCALE
o^__S^^iO 20 3£ 40 miles



Pl.ATK LXVI



PI.ATK LXVII



Platk Lxvni



ri.ATE LXix



Plate LXX



Plate LXXI



Plate LXXII



Plate LXXIII



Platk LXXIV



Plate LXXV



Plate LXXVI



Plate LXXVII



Plate LXXVIII



Plate LXXIX



Plate LXXX

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12

10

8

6

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Plate LXXXl

Parts psr f^iLLioN

Mii3issipni Ki'vei—

Moms
Dresden

Lockport



Plate LXXXII



Plate LXXXIII



Plate LXXXIV



Plate LXXXV

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