GEOLOGICAL SURVEY CIRCULAR 781

The Case of the 

Shrinking Channel 

the North Platte and 

Platte Rivers in Nebraska
The Case of the 

Shrinking Channels 

the North Platte and 

Platte Rivers in Nebraska

By Garnett P. Williams

GEOLOGICAL SURVEY CIRCULAR 781

1978
United States Department of the Interior

CECIL D. ANDRUS, Secretary

Geological Survey

H. William Menard, Director

Free on application to Branch of Distribution, U.S. Geological Survey, 7200 South Eads Street, Arlington, VA 22202
CONTENTS

Page

Metric-English equivalents ............................................... IV

Abstract ............................................................................

Introduction ......................................................................

Geographic setting ............................................................

Hydrology .........................................................................

General ......................................................................

Peak discharges .........................................................

Mean annual discharges ............................................

Days of no flow .........................................................

Theoretical channel changes .............................................

Channel characteristics .....................................................

Width ........................................................................

Data and procedure ...........................................

Results ................................................................

Channel characteristics Continued 

Vegetation ...................................

Braiding .......................................

Definition .............................

Measurements ......................

Results ..................................

Sinuosity ......................................

Definition .............................

Results ..................................

Bed aggradation and degradation 

Method of analysis ...............

Results ..................................

Conclusions ........................................

References ...........................................

Page

20

21

21

23

24

25

25

25

26

26

27

34

39

ILLUSTRATIONS

Page

FIGURE 1. Platte River study area .......................................................................................................................................... 2

2. Main water-use features of the Nebraska Public Power District and the Central Nebraska Public Power and

Irrigation District ................................................................................................................................. 3

3-16. Photographs:

3. Site of old Bayard bridge ........................................................................................................................ 7

4. Site of old Camp Clark bridge about 8 km west of Bridgeport .............................................................. 8

5. North Platte River at Bridgeport ............................................................................................................. 10

6. Union Pacific Railroad bridge, North Platte River at North Platte ........................................................ II

7. Platte River bridge at Kearney, about 1900 ............................................................................................ 12

8. Site of old Platte bridge at Kearney 1977 views, looking north ............................................................ 13

9. Platte River bridge about 8 km southeast of Grand Island, about 1900 ................................................. 14

10. Site of old Platte River bridge (fig. 9) southeast of Grand Island 1977 views ...................................... 15

11. Comparative aerial views (1938 and 1969) of Platte River channels about 6 km west of Cozad ............ 16

12. Comparative aerial views (1938 and 1969) of Platte River channels about 2 km south of Cozad ........... 17

13. Comparative aerial views (1938 and 1969) of Platte River channels about 7 km west of Lexington ...... 18

14. Comparative aerial views (1938 and 1969) of Platte River channels about 12 km west of Kearney ........ 19

15. Comparative aerial views (1938 and 1969) of Platte River channels directly south of Kearney .............. 20

16. Comparative aerial views (1938 and 1969) of Platte River channels south of Shelton about 1 km east

of Buffalo County-Hall County line ................................................................................................. 21

17-19. Graphs:

17. Channel width at different time periods .................................................................................................. 24

18. Proportion of 1865 width occupied by 1965 channel ............................................................................... 25

19. Channel width changes at the Chicago, Burlington, and Quincy (Burlington Northern) Railroad bridge,

Platte River near Grand Island, Nebr. ............................................................................................. 26

20. Sketch of channel width changes due to bridge, Platte River, 2.4 km south of Kearney ........................ 27
FIGURE 21-24. Graphs:

21.

22.

23.

24.

25.

26.

27.

28.

29.

Page

Historical trends of annual peak flows, mean annual flows and channel width. North Platte River at North

Platte .............................................................................................................................................. 30

Relation of channel width to 5-year-averaged annual peak flows, North Platte River at North Platte 31

Relation of channel width to 5-year-averaged mean annual flows. North Platte River at North Platte 31

Historical trends of annual peak flows, mean annual flows and channel width, Platte River near Overton 32

Relation of channel width to 5-year-averaged annual peak flows, Platte River near Overton .............. 33

Relation of channel width to 5-year-averaged mean annual flows, Platte River near Overton .............. 33

Changes in braiding index with distance downstream ........................................................................... 34

Changes in channel sinuosity with distance downstream ....................................................................... 35

Changes in bed elevation during the past 45 years at 12 U.S. Geological Survey gaging sites .............. 36

TABLES

TABLE 1. Major storage reservoirs in the North Platte River basin in dowstream order .......................

2. Average water discharges (geometric means) for selected historical periods ...........................

3. Basic for channel width, braiding and sinuosity .....................................................................

4. Basic data for mean bed elevation, in meters above mean sea level, at various time periods .

5. Historical discharge data for North Platte and Platte gaging stations within the study reach

Page 

3

5

22

28

40

METRIC-ENGLISH EQUIVALENTS

Metric Unit English equivalent

millimeter (mm)

millimeter (mm)

meter (m)

kilometer (km)

cubic meter per second (m3/s)

= 0.0394 inch

= .00328 foot

= 3.28 feet

= .62 mile

= 35.3 cubic feet per second

IV
The Case of the Shrinking Channels the North Platte 

and Platte Rivers in Nebraska

By Garnett P. Williams

ABSTRACT

This reconnaissance investigation was undertaken to determine 

whether the channels of the North Platte and Platte Rivers in 

western and central Nebraska have been changing in character since 

the latter part of the 19th century and, if so, the general nature and 

extent of such changes. The 480-kilometer study reach extended 

from Minatare on the North Platte River to Grand Island on the 

Platte River.

The channels have indeed changed considerably. Changes in the 

365-km reach from Minatare to Overton differ in magnitude and 

sometimes in character from the downstream stretch from Overton 

to Grand Island (115 km). Within the former reach, the channel by 

1969 was only about one- to two-tenths as wide as in 1865. The 1969 

channel for this reach was less braided and slightly more sinuous 

than the 1938 channel. (No data are available for braiding and 

sinuosity prior to 1938.) From Overton to Grand Island, the 1969 

channel was about six- to seven-tenths as wide as in 1865, and 

various changes in braiding and sinuosity took place between 1938 

and 1969.

The decreases in channel width are related to decreases in water 

discharge. Such flow reductions have resulted primarily from the 

regulating effects of major upstream dams and the greater use of 

river water by man. Much of the former river channel is now 

overgrown with vegetation.

INTRODUCTION

The North Platte and Platte Rivers in Nebraska (fig. 

1) are among the most important rivers of the Great 

Plains. Much of the vast westward migration of the 

19th century followed their routes, and travelers 

cursed and praised the rivers simultaneously for their 

benefits and disadvantages. Settlers depended on these 

rivers for water and built a very complex system of 

diversions and controls. Wildlife, too, plays a large 

role. Sandhill cranes, for example, use the North Platte 

and Platte channels as a major migration stopover. In 

mid-March each year, an estimated 70-80 percent of 

the world's lesser sandhill cranes move into a 260-km

stretch of the river between Sutherland and Grand 

Island (fig. 1) (Frith, 1974; Farrar, 1975).

Is man's extensive manipulation of the water flow 

changing the riverine habitat? This reconnaissance 

investigation examines the character of the Platte's 

channel to determine whether any significant changes 

have taken place since the latter part of the 19th 

century.

Local historians Emil Roeser, Paul Henderson, and 

Ted Genoways took me on interesting excursions to 

old bridge sites, most of which today are unrecognizable as the important crossings they once 

were. Many people generously provided information 

and assistance during the study. Among these are 

Frank Dragoun of the Central Nebraska Public Power 

and Irrigation District, Glenn Tabor of the Union 

Pacific Railroad, Jim Potter and Paul Riley of the 

Nebraska State Historical Society, Jim Holmes of the 

Nebraska Department of Roads, Harold Nagel and 

Steele Becker of Kearney State College, Robert 

Petersen of the Nebraska Public Power District, 

Emery Coonrod and Ernie Peterson of the Burlington 

Northern Railroad, Warren Corbet and Fred 

Otradovsky of the U.S. Bureau of Reclamation, and 

Ray Bentall of the University of Nebraska-Lincoln. 

Ray Bentall, Richard Hadley, and Stanley Schumm 

improved the manuscript considerably with their 

many constructive comments.

GEOGRAPHIC SETTING

The North Platte River originates in the Rocky 

Mountains of Colorado, flows northward into central 

Wyoming, then generally southeastward into 

Nebraska. In west-central Nebraska it joins the South
FIGURE I. Platte River study area.

Platte River to form the Platte River (fig. 1). The Platte 

flows eastward to join the Missouri River at the eastern 

edge of Nebraska.

The reach studied in this report extends from 

Minatare on the North Platte River, about 50 km east 

of the Wyoming-Nebraska boundary, to Grand Island 

on the Platte River in central Nebraska, a river 

distance of about 480 km (fig. 1). Throughout most of 

this stretch, the river is several hundred meters wide 

and only 0-2 m deep. The drop in elevation is from 

1,162 m above mean sea level at Minatare to 558 m 

above mean sea level at Grand Island or about 604 

m an average slope of about 0.00126 m/m.

Many islands of various sizes, some bare sand and 

others completely vegetated, dot the channels. This 

gives the rivers a braided pattern. Few tributaries of 

any size enter the study reach from the south, but 

several enter from the north. Alluvial sand, gravel, and 

loam make up most of the Platte valley. The adjacent 

plains consist mainly of loess.

The climate ranges from semiarid in the west to 

subhumid in the east. Mean annual rainfall near Lake 

McConaughy is about 460 mm and this gradually 

increases eastward to about 625 mm at Grand Island. 

About 80 percent of the annual precipitation falls 

during April-September. A few violent thunderstorms 

usually occur in late spring and early summer.

HYDROLOGY 

GENERAL

Analysis of U.S. Weather Bureau precipitative data 

for North Platte, Kearney, and Grand Island reveals 

that there have been no significant long-term trends or 

changes in total annual precipitation for these cities 

during the period 1900-74. Therefore, any observed 

long-term changes in streamflow probably are not 

attributable to changes in climate.

Flow in the North Platte and Platte Rivers depends 

not only on climatic and geologic conditions but also 

on many influences of man. Transmountain diversions 

occur in the headwaters of the North Platte. Several 

dams on the North Platte (table 1) detain and store the 

flow and regulate the downstream discharge. Within 

the study reach, many structures especially Keystone 

Dam (and Sutherland Canal) since 1937 and the 

Tri-County Diversion Dam (and Tri-County Canal) 

since 1941 divert significant amounts of river water 

via canals to offstream reservoirs, irrigated croplands, 

or powerplants (fig. 2). A considerable quantity of 

ground water is pumped from wells for irrigation of 

lands bordering the Platte River. Excess irrigation 

water and hydropower releases reenter the Platte at 

various locations. Increasing population over the years 

has demanded more and more water from the river.
101°

FIGURE 2. Main water-use features of the Nebraska Public Power District and the Central Nebraska Public Power and Irrigation District 

T\HI.E I. Major storage reservoirs on the North Piaffe River, in 

downstream order

[Horn Diagoun. K .1 . unpublished data. ls>7h]

Name ol

Hate Maximum stotage

storage eapactn

began (m'l

Nearest town

Scminoe ............ April 1. 1939 1.25x10' Leo. Wyo.

Pathfinder .........April 1909 1.26xlOy Alcova.'Wyo.

Alcova ..............Feb. 8, 1938 2.35x10* Alcova, Wyo.

Glcndo ..............Oct. 17, 1957 9.84x10* Glendo, Wvo.

Guernsey ...........July 1927 5.52xl07 Guernsey, Wyo.

MeConaughy ....Feb. 9. 1941 2.40X104 Ogallala", Nebr.
Furthermore, the greater amount of vegetation 

(described later in this report) now growing along the 

present channel probably consumes much more water 

through evaportranspiration than formerly (Dragoun, 

unpublished report, 1976).

Irrigation along the Platte began about 1870 

(McKinley, 1938, p. 101). The benefits of irrigation 

were viewed somewhat skeptically for the following 20 

years or so, in spite of several impressive examples of 

its usefulness. General acceptance of irrigation came in 

the 1890's, at which time the total mileage of irrigation 

ditches and canals expanded rapidly. (See Bentall, 

1975, p. 24-34, for a summary of the history of 

irrigation.)

What have been the effects of all these influences of 

man on the river's flow characteristics? It is impossible 

to isolate and identify the influence of any one factor 

(storage reservoir, irrigation diversion, and so forth), 

because (1) several such factors have operated in 

varying degrees simultaneously, and (2) measurements 

of water discharge are scarce for most gaging stations 

prior to the 1930's. Nevertheless, it might be possible to 

determine roughly the effects of certain major influences, such as big dams.

Table 5, at the end of this report, gives the entire 

record available of annual peak flows, mean annual 

discharges, and number of days per year of no flow for 

each of the 12 gaging stations in the study reach. The 

stations are listed in downstream order. All data were 

taken from U.S. Geological Survey publications, 

especially water-supply papers. For the present study, 

the data were converted into metric units.

PEAK DISCHARGES

Dams store water for irrigation and hydroelectric 

power production. They also provide some measure of 

downstream flood protection by detaining or impeding the big flows. The more dams that are built, the 

greater the likelihood that the natural high flows will 

be retarded. The peak-flow data in table 5 should 

reveal whether this has been accomplished on the 

North Platte and Platte Rivers, if we can assume that 

the effects of canals and other diversions on peak flows 

are small compared to the effects of the major dams. 

Discharges measured prior to 1909, when Pathfinder 

was built, most closely represent natural flows. The 

magnitudes of all post-1909 peaks are to varying 

degrees the result of an increasing amount of control 

by man as more and more dams and diversion 

structures have been built.

Table 2, based on the data in table 5, shows the 

average yearly peak flows for the approximate time 

periods indicated by the dam constructions in table 1.

The brief period from 1971 to the present is omitted in 

this analysis because in 1971, 1973, and 1974, the 

various reservoirs had to bypass abnormally large 

inflows from spring snowmelt, thus producing unusually high peaks for stations in the study reach 

(Bentall, 1975, p. 7-9).

The first four stations (Minatare to Lewellen) are 

not influenced by Lake McConaughy (1941 and later) 

and are less affected by major diversions. These 

stations therefore are more apt to reveal the approximate effects of the upstream dams on peak 

discharges. Table 2 shows that, for each of these 

stations, average peak discharge has decreased consistently and progressively after closure of each major 

dam.

Discharges at some or all of the stations downstream 

from Lewellen have been influenced since the 

mid-1930's or shortly thereafter by Lake McConaughy, the Sutherland Canal, the Tri-County 

Canal, Johnson Power Plant releases (fig. 2), and other 

features. Average peak flows for all periods of record 

prior to 1957 decreased consistently. The average peak 

discharges for the period 1957-70 have increased 

slightly (table 2).

At the three stations having records in the pre-dam 

era (before 1909), the average yearly peak flow for the 

most recent period (1957-70) was only about 0.1-0.2 of 

the average peak flow for the pre-1909 period. This is a 

considerable reduction. At the seven stations having 

records for both the 1909-27 and 1957-70 periods, the 

average peak flow for the latter period was only about 

0.1-0.3 of the average yearly peak for the earlier period.

MEAN ANNUAL DISCHARGES

By withholding or diverting water which otherwise 

would flow downstream, dams also lower the mean 

annual discharges at downstream stations, unless 

other factors influence the flow. The right-hand part of 

table 2 shows average values of mean annual discharge 

for the same time periods discussed earlier. As with 

peak flows, the pre-1909 flows were least affected by 

man, whereas flows in recent decades were almost 

entirely regulated and used.

As with peak discharges, the average values of mean 

annual discharge at most gaging stations have generally decreased with successive time periods. This trend is 

most pronounced at the upstream stations, as expected. For the two stations which have records prior 

to 1909, namely Bridgeport and North Platte, the 

average of the mean annual discharges for the 1957-70 

period was roughly 0.2-0.3 that of the pre-1909 period. 

Four stations (table 2) have enough data to permit a 

comparison of the 1909-27 and 1957-70 periods.
TABLE 2. Average water discharges (geometric means) for selected historical periods

[Each period begins with closure ol an upstream dam. Numbers in parentheses are numbers ol years ol record a\ailable within applicable period]

Station

Minatare

Bridgeport

Li sco

Lewellen

Keystone

Sutherland

North Platte

Brady

Cozad

Overton

Odessa

Grand Island

Before 

April 1909

736 (1)

440 (9)

- (0)

- (0)

- (0)

- (0)

511 (14)

- (0)

- (0)

(0)

- (0)

- (0)

Average o 

per

April 1909- 

June 1927 ,

300 (12)

261 (13)

311 (2)

(0)

575 (1)

575 (1)

295 (18)

(0)

(0)

443 (10)

(0)

(0)

f yearly peak flows 

second, for period

July 

. March

140

149

116

-

-

152

217

218

204

293

196

312

1927- 

1939

(11)

(12)

(8)

(0)

(0)

(5)

(13)

(2)

(D

(12)

(3)

(6)

April 

Oct.

92

110

107

118

76

59

73

87

79

150

145

169

, in cubic meters 

indicated

1939- 

16, 1957

(19)

(18)

(18)

(17)

(16)

(18)

(18)

(18)

(18)

(18)

(18)

(18)

Oct. 17 

1970

72

91

84

96

81

68

72

100

84

140

165

174

, 1957-

(13)

(13)

(13)

(13)

(13)

(13)

(13)

(13)

(13)

(13)

(13)

(13)

Average of mean a

Before 

April 1909

- (0)

83 (4)

- (0)

- (0)

- (0)

- (0)

88 (13)

- (0)

- (0)

- (0)

- (0)

- (0)

April 1909- 

June 1927

63 (5)

67 (11)

- (0)

- (0)

- (0)

- (0)

80 (18)

- (0)

- (0)

101 (13)

- (0)

- (0)

nnual dischar

July 

March

30

38

31

-

-

26

50

52

-

51

38

28

1927- 

1939

(11)

(12)

(8)

(0)

(0)

(3)

(13)

(D

(0)

(12)

(2)

(6)

ges, in cubic 

d indicated

April 1939- 

Oct. 16, 1957

22 (19)

31 (18)

34 (18)

39 (16)

11 (15)

9.8(18)

17 (18)

12 (18)

9.6(18)

29 (18)

25 (18)

26 (18)

Oct. 17, 1957- 

1970

19 (13)

28 (13)

31 (13)

33 (13)

8.4(13)

8.8(13)

16 (13)

11 (13)

8.8(13)

33 (13)

31 (13)

33 (13)

Minatare's average mean annual discharge for 1909-27 

was 63 m3 /sand for 1957-70 was only 19m3 /s, or only 

0.30 of the former value. Similar comparisons for the 

Bridgeport, North Platte, and Overton stations show 

the recent (1957-70) flows to have been 0.42, 0.20, and 

0.33, respectively, of the 1909-27 values.

In general then, both peak discharges and mean 

annual discharges have decreased significantly over 

the years at most stations. Table 2 shows that many of 

these reductions correlate with the appearance of 

upstream dams.

DAYS OF NO FLOW

Long-time residents in the downstream part of the 

study reach say that the river was often completely dry 

in late summer. For the period of record (at least the 

last 35 years or so), all stations within the study reach 

except the two farthest downstream (Odessa and 

Grand Island) have, with rare exceptions, carried 

water throughout the year (table 5).

The Overton station had no flow at times in 1919, 

1922, 1925, 1927-28, and 1930-41. In 1941 the 

Tri-County Canal system began routing water back 

into the Platte River about 11 km upstream from the 

Overton gaging station, and since then the Platte at 

Overton has always had some flow.

The Odessa and Grand Island stations do have some 

rather dry years, at times. For these stations, the 

meager data of table 5 indicate fewer days of no flow 

after 1941 than before, with Grand Island usually 

having more such days than Odessa.

Because of the upstream dams and the decrease in 

water discharge, the sediment loads in the study reach 

probably have decreased also.

THEORETICAL CHANNEL CHANGES

The response of a channel to a decrease in both 

water and sediment discharge can be predicted 

qualitatively but not quantitatively. Schumm( 1969, p. 

261) presents the following relation, in which ( + ) 

designates increase and (-) designates decrease:

where Q =\vater discharge, (^percentage °f tota ' 

sediment that is bedload, H-banktull width, 

L=meander wavelength, £>=maximum channel depth. 

S=slope, and /^sinuosity.

Compared with the channel of the latter part of the 

19th century, the present channel therefore should 

show a decrease in width, a decrease in meander 

wavelength, a decrease in the width/depth ratio, and 

an increase in sinuosity. Slope and maximum depth 

today could be greater than, equal to, or less than their 

former values.

The meander wavelength is not applicable to the 

study reach because the river tends to be braided rather 

than meandering. The next section describes changes 

in the remaining dependent variables and in other 

channel features.
CHANNEL CHARACTERISTICS

Photographs are an excellent way to compare the 

general nature of the river channel at different times. 

Unfortunately, old pictures of the North Platte and 

Platte Rivers are scarce. I did find a few, however, and 

took or obtained pictures of the same sites as they look 

today (figs. 3-10).

Comparison of the old and new pictures of the same 

sites reveals that the 1977 channel is radically different 

from that of 70-100 years ago. The most striking 

changes apparent from the photographs are a decrease 

in channel width and an increase in vegetation.

Historical accounts, in addition to the above 

photographs, verify that the North Platte and Platte 

Rivers were very wide in the 19th century. Estimates of 

six different explorers, from Robert Stuart in 1813 to 

Jesse Gove 1857, indicate that the river width at 

various points along the study reach ranged from 

about '/2 to 3 miles (800-4,800 m). Fremont (1843, p. 

19), in the report on his 1842 scientific exploration of 

the Platte, stated that the channel was 5,350 feet (1,630 

m) wide immediately below the junction of the North 

Platte and South Platte Rivers. The Union Pacific 

Railroad survey of 1866 agrees with this figure and also 

indicates that the Platte River from Kearney to North 

Platte was about V4 to W* miles (1,200-2,000 m) 

wide. The U.S. Government survey of 1865-70, discussed in more detail below, shows about these same 

widths in this reach. As the present photographs (figs. 

3-10) show, the 1977 channel is considerably narrower.

From about 1938 to about 1969 the U.S. 

Department of Agriculture has taken aerial 

photographs of much of the study reach. A comparison of the photographs of a given area shows what 

general changes, if any, have taken place over that 

recent 31-year period. This comparison probably is 

most useful for the reach from Lake McConaughy 

downstream, because the first set of aerial 

photographs was taken just before construction of the 

dam and lake.

Figures 11-16 show the 1938 channel compared to 

the 1969 channel at selected reaches. All photographs 

shown here were taken during July. These 

photographs, while not chosen randomly for presentation, are fairly representative. Once again a general 

decrease in channel width and an increase in vegetation 

appear. To describe these and other features more 

completely, detailed measurements or additional 

observations were made, as described in the following 

paragraphs.

WIDTH

DATA AND PROCEDURE

Measurements of channel width were made from the 

original U.S. Government plats of Nebraska (about 

1865-75), U.S. Department of Agriculture 1938 aerial 

photographs, and U.S. Geological Survey topographic 

maps (various years generally within the period 

1962-72). These three major sources of data permitted 

a determination of channel width at three different 

times (hereafter referred to as 1865,1938, and 1965). In 

addition, some measured cross sections were provided 

by the Burlington Northern Railroad (formerly 

Chicago, Burlington, and Quincy Railroad), Nebraska 

Department of Roads, U.S. Geological Survey, Union 

Pacific Railroad, Central Nebraska Public Power and 

Irrigation District, and the U.S. Bureau of Reclamation.

Channel-width determinations were made simply by 

measuring the bank-to-bank width at the cross section 

of interest on the particular map or aerial photograph. 

In computing channel width, the width of stabilized 

islands (those covered by perennial vegetation) was 

subtracted from the bank-to-bank width of the general 

channel. Where the Platte River separates into several 

distinct channels, the channel width was taken as the 

sum of the various individual channels. Thus the width 

data presented here approximately represent the width 

of flowing water at bankfull flow.

Most of the available measured cross sections are at 

bridges. These sections do not necessarily reflect the 

kinds of channel changes that occur in more natural 

reaches. A selection of natural cross sections was made 

by measuring channel width at the eastern edge of 

every other range (R. 54 W., R. 52 W., and so 

forth). This provided 23 sites within the study reach. 

(Two range lines happened to fall at bridges, and for 

these cases the measuring site was moved 0.5 km 

upstream.)

RESULTS

Table 3 and figure 17 show the channel width in 

1865, 1938, and 1965. The widths at any one time do 

not show any systematic change in the downstream 

direction. However, the graphs clearly show the 

overall decrease in channel width that has occurred 

over the past 100 years. The channel in 1938 was 

somewhat narrower than it was in 1865 at those sites 

for which 1938 aerial photographs were available. By 

1965 the channel at all measuring sites was still 

narrower. Figure 18, which depicts the proportional 

decrease in width from 1865 to 1965, shows that in
FIGURE 3. Site of old Bayard bridge. /4, bridge used from about 1900-1913. Photo from Nebraska State Board of Irrigation, Highways, and Drainage, 1914, p. 172. B, 1977 view of

, same cross section. C, piers of 1900-1913 bridge several hundred meters from present (1977) left bank.
1965 the channel at many cross sections was only about 

0.1-0.2 as wide as it was in 1865. Recent field 

measurements of the channel width at several sites 

agree reasonably well with widths measured on recent 

topographic maps.

The lesser decrease in width that has occurred in the 

downstream 115 km or so of the study reach (fig. 18) 

probably is due to the Johnson Power Plant returns to 

the Platte at about kilometer point 408, about 11 km 

upstream from Overton.

The process of channel narrowing has been 

accelerated locally at railroad and highway crossings. 

Here the builders usually try to reduce construction 

expenses by constricting the channel at the time of 

construction by dumping in artificial fill along the 

travel route. At some crossings additional fill was 

dumped on subsequent occasions after the original 

completion of the crossing (fig. 19).

Such artificial constrictions of the channel typically 

interrupt the flow and cause the river to deposit 

sediment along both banks just upstream and 

downstream from the bridge, especially downstream 

(figs. 12-15, 20). The deposit seems to extend only for 

about a distance of one or two channel widths (original 

channel) from the bridge. Bridges, therefore, have had 

only local effects on the overall narrowing of the Platte 

and are not the major cause of the narrowing.

The size of a river channel depends to a significant 

extent on the water discharge. Large discharges create 

big channels; whereas, small flows carve small 

channels. The North Platte and Platte Rivers in the

late 1800's carried high discharges and were very wide, 

as the hydrology and channel width discussions have 

shown. The present channels carry low and sustained 

flows and are relatively narrow compared to the early 

days. Figures 21-26 show the general trend by which 

the channel width has decreased as a function of the 

water flow at two sites North Platte River at North 

Platte (1.4 km upstream from the Union Pacific 

Railroad bridge) and the Platte River near Overton (2 

km upstream from the gaging station). The procedure 

in constructing these figures for each station was as 

follows:

1. The flow data of table 5 were condensed into 

5-year arithmetic averages and were plotted against 

year (figs. 21 A, 21 B, 24A and 24B). (The average 

discharge of each 5-year period was plotted against the 

mid-year of that respective period.) 

2. A line was sketched by eye to represent the 

approximate long-term general trend of the discharges. (1 considered the abnormally high flows of 

1971, 1973 and 1974 to be atypical, that is, not 

representative of the general trend since 1940.) 

3. A plot of channel width versus year was made by 

plotting the measured width against the corresponding 

year for that width (figs. 21 C and 24Q. For this 

purpose two width values for each station were 

obtained from the original plats of Nebraska (about 

1868) and the 1938 aerial photos, mentioned earlier. 

Additional widths for the North Platte site were 

measured from the 1899 15-minute U.S. Geological 

Survey topographic map, a 1965 U.S. Dept.

FIGURE 4. Site of old Camp Clark bridge about 8 km west of Bridgeport. A, bridge used from about 1876-1903. View may be from an island 

in the river. Photograph from Paul Henderson. B, view of site in 1968. Present bank of river is just below lower edge of photograph. 

Arrows point to remaining piers of old bridge. Photograph from Joe Fairfield.

FIGURE 5. North Platte River at Bridgeport, looking north. A, old bridge (right), with newer bridge under construction, about 1913. 

Photograph from Nebraska State Board of Irrigation, Highways, and Drainage, 1914, p. 188. B, the same cross section in 1977.

10
FIGURE 6. Union Pacific Railroad bridge,North Platte RiveratNorth Platte, looking northeast. A, 1869view(W. H.Jackson photograph, from U.S. Geological Survey files);

B, 1977 view taken from about same location as A; C, the main channel in 1977.
FIGURE 7. Platte River bridge at Kearney, probably about 1900. Photograph from Nebraska State Historical Society.
.. . "":~im

A

FIGURE 8. Site of old Platte River bridge at Kearney 1977 views, looking north. A, scene from right bank, showing old bridge piers; B, 

view showing old piers (arrows) on present flood plain, as well as piers in channel. Woman standing on top edge of right bank.

13
FIGURE 9. Platte River bridge about 8 km southeast of Grand Island (location of present U.S. Highway 34 bridge), looking southeast, about

1900. Photograph from the Stuhr Museum of the Prairie Pioneer.
FIGURE 10. Site of old Platte River bridge (fig. 9) southeast of Grand Island 1977 views. A, view of cross section from about same point as

fig. 9; B, present channel, looking northwest.

15
(N i t

'^^SK^'i* 5 ;- v^v%t. ^mfe .?.:, 'W^

i- ».\v;» > ^VJSK-1 * ;'$*fe # v^s-J't*.-.^^

« ' " - ' -. ' ^'i'^ ,' ; "* '''"'- ' '"' ' ^-" ?rH, : '.'^^ ,; v"

Y^.;

'-.^

> . / ' i.'V **'* ' ?,<* 

- vm

FIGURE 11. Comparative aerial views of 1938 (A) and 1969 (B) channels of Platte River about 6 km west of Cozad and about 368 river km

from Nebraska-Wyoming line. Photos from U.S. Dept. Agriculture.
FIGURE 12. Comparative aerial views of 1938 (A) and 1969 (ff) channels of Platte River about 2 km south of Cozad and about 374 river km

from Nebraska-Wyoming line. Photos from U.S. Dept. Agriculture.
FIGURE 13. Comparative aerial views of 1938 (A) and 1969 ( B) channels of Platte River about 7 km west of Lexington and about 384 river 

km from Nebraska-Wyoming line. Photos from U.S. Dept. Agriculture.

18
FIGURE 14. Comparative aerial views of 1938 (A) and 1969 (J5) channels of Platte River, about 12 km west of Kearney, at the U.S. 

Geological Survey gaging station near Odessa (river km 443). Photos from U.S. Dept. Agriculture.

Agriculture aerial photo (same type and scale as the 

1938 photo) and the U.S. Geological Survey's 1970 

7'/2-minute topographic map. For the Overton site 

additional widths were obtained from a 1951 U.S. 

Dept. Agriculture aerial photo, 1962 U.S. Geological 

Survey 7'/2-minute topographic map and 1969 U.S. 

Dept. Agriculture aerial photo (same scale as the 1938 

photo).

4. A line was drawn by eye to show the approximate 

long-term general trend of the channel width (figs. 21C 

and 24C).

5. At the mid-year of each successive 5-year period, 

values of width and associated discharge were read

from the appropriate curves.

6. For each station and type of discharge (peak flow 

and mean annual flow), a graph of width versus 

discharge was constructed, consisting of the plotted 

points for all 5-year periods (figs. 22, 23, 25 and 26). 

Figures 22, 23, 25 and 26 show the circuitous trend 

which the width-discharge relations have followed at 

the North Platte and Overton reaches, during the 

period of record. The figures also give a perspective of 

the reductions in width and flow that have occurred at 

these sites. For example, by 1965-69 the average 

annual peak flows at the North Platte site were only 

about 0.15 of their 1895-99 values. Mean annual flows

19
FIGURE 15. Comparative aerial views of 1938 (A) and 1969 (B) channels of Platte River, directly south of Kearney (bridge of State Routes 10

and 44), at river km 457. Photos from U.S. Dept. Agriculture.

by 1965-69 were about 0.2 of what they were at the turn 

of the century at North Platte, and the channel was 

only 0.14 as wide. At the Overton site the 1965-69 peak 

flows, mean annual flows and channel width were each 

about 0.3 of their 1915-19 values. Other sites in the 

study reach have undergone comparable reductions, as 

the flow and width data presented above have shown.

VEGETATION

Explorers' reports generally agree on the amount of 

vegetation along the North Platte and Platte River in 

the 1800's. The numerous islands in the river for the 

most part were heavily wooded in those days, usually 

with cottonwood and willow trees. The river banks, on 

the other hand, only rarely had any trees. The 

shorelines of the North Platte River within the study 

reach, especially the left bank, were particularly

barren: "...not a twig to be seen..." (Robert Stuart, 

1813 in Rollins, 1935, p. 210); "You will find no more 

timber on the north side of the river for 200 miles 

except one lone tree" [starting up the North Platte] 

(Clayton, 1848, p. 8).

In spite of the agreement on the scarcity of trees and 

shrubs along the North Platte and Platte's banks 

during much of the 19th century, there is little 

agreement as to the cause of this. Some of the theories 

are that the trees didn't like the growing conditions, 

Indians and white travelers chopped down the trees for 

firewood, prairie fires destroyed the trees, big floods 

periodically washed out the young trees, and buffalo 

and other animals ate all the available vegetation. The 

trees certainly were cut down in some areas, such as 

near Kearney in 1848-49 for the construction of Fort 

Kearney.

20
FIGURE 16. Comparative aerial views of 1938 (A) and 1969 (B) channels of Platte River south of Shelton about 1 km east of Buffalo 

County-Hall County line and at river km 490. Photos from U.S. Dept. Agriculture.

Today's channel seems to have more trees along the 

banks than during most of the 19th century. More 

striking, however, is the lush vegetation, including 

trees of all sizes, that occupies much of the zone that 

used to be stream channel (figs. 3-16).

The development of vegetation on sandbars within 

the old channel typically begins with sedges (Carex 

sp.). Grasses follow, and finally dense willows and 

other trees take hold (Ruby, 1952). Field observations, 

other studies (Sutherland, 1974; Bunde and others, 

1975), and U.S. Geological Survey gaging station 

descriptions indicate that the kinds of trees within the 

study reach today are mainly willow, cottonwood, elm, 

ash, elder, and hackberry. Grasses, ragweed,

sunflowers, dogwood, and mulberry bushes plus many 

other plants complement the tree growth.

BRAIDING

DEFINITION

Braiding is the formation of two or more alluvial 

channels, separated by one or more islands, within a 

main channel. The process tends to produce a network 

of small interlaced channels separated by islands or 

bars.

The present evaluation of braiding considers only 

islands and omits bars. For this purpose, an island is 

defined as a land mass which is located within the main

21
TABLE 3. Basic data for channel width, braiding, and sinuosity

a

Number Station River distance from 

Nebr.-Wyo. line 

(km)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

Minatare

R52W

Bridgeport

R50W

R48W

Lisco

R46W

R44W

Lewellen

R42W

R40Wb

Keystone

R38W

R36W

R34W

Sutherland

R32W

North Platte

R30W

R28W

Brady

R26W

R24W

Cozad

R22W

Over ton

Overton (R20W)

R18W

53.3

78.8

90.8

98.4

120.3

135.6

141.6

166.3

182.9

187.5

206.9

225.4

226.8

247.4

266.9

270.8

286.8

302.6

312.9

332.0

338.8

353.5

375.5

376.3

397.0

418.6

419.1

438.5

Total channel width (m)

1865 1938

975

810

1140

810

1255

1280

1060

545

885

810

710

950

940 200

850 815

750 325

410

740 460

790 520

1200 560

1145 975

1250 340

1405 1215

1070 435

920 440

1380 1155

1610 1520

1465 880

1660 1335

22

1965

55

105

120

130

170

150

185

200

150

165

-

c

45

45

195

75

45

90

120

185

45

90

140

40

60

335

335

1135

Braiding index Sinuosity

1938 1965 1938 1965

_

- - -

- - -

- - -

- - -

_

_

_

- - -

- - -

_

1.21 0.0° 1.06 l.OO'

1.21 0.0 1.06 1.00

8.13 2.58 1.00 1.11

2.23 0.26 1.06 1.11

2.13 2.20 1.05 1.30

3.48 1.91 1.03 1.05

3.44 1.76 1.06 1.11

1.26 0.80 0.97 1.05

_

0.18 0.51 1.12 1.18

10.93 4.09 1.05 1.16

7.35 4.70 1.05 1.08

_

2.92 2.02 1.01 1.05

2.03 1.53 1.11 1.05

_

6.71 5.17 1.00 1.08
TABLE 3. Basic data for channel width, braiding, and sinuosity Continued

Number Station' River distance from Total channel width (m) Braiding index Sinuosity 

Nebr.-Wyo. line

(km) 1865 1938 1965 1938 1965 1938 1965

29

30

31

32

33

34

35

Odessa

R16W

R14W

R12W

,

R10W

R9W (Approx.)

Grand Island

442.

458.

478.

499.

518.

527.

529.

6

7

2

0

6

2

6

1250 930

1405 1185

950 700

1220 1090

655 655

-

730

490

940

495

885

465

-

760

-

0.

0.

0.

1.

0.

-

78

486

98

06pe

66

-

5.85

0.606

4.55

p

0.716

1.34

-

1

0

1

1

1

-

.00

.98 e

.00

p

.00

.00

-

-

1.05

0.985*

1.00

1.005*

1.00

-

Name, location of USGS gaging station; range, cross section where river crosses 

eastern edge of designated range.

Middle of Lake McConaughy. 

"^Artificially straightened sometime between 1938 and 1969.

One-half km upstream, to avoid bridge section.

g Braiding index and sinuosity = average of two channels.

channel, is surrounded by water channels, and is 

stabilized by perennial vegetation.

The degree of braiding is here measured by a 

"braiding index" (B.I.), defined as

sum of length of islands in reach

D l ________ - __ _ 

length of reach, measured midway between banks

This definition is patterned after, and similar to, that 

which Brice (1964, p. D27) proposed. The difference is 

that Brice multiplied the numerator by 2, thus obtaining for the numerator an approximation of the 

sum of island perimeters, rather than their lengths.

With the present definition, a B.I. of zero means the 

stream is not braided (has no islands). A B.I. of 0.5 

means that island lengths amount to one-half the 

length of the reach measured. Similarly, if the sum of 

the island lengths equals the length of the reach, the 

B.I. is 1.0; if the sum is 10 times the length of the reach, 

the B.I. is 10.0.

The braiding index is not perfect in that a reach with 

many small islands could produce a braiding index 

that is less than, equal to, or greater than the same 

reach distance with one large island. A complete 

braiding index probably should include not only the 

lengths of the islands but also their number and 

density. The latter two features are reflected only 

indirectly in the braiding index used here. In many 

situations, however, the present braiding index should 

be generally indicative of anastomosing tendencies 

within a channel.

MEASUREMENTS

Braiding indices were measured from Keystone to 

Grand Island, a distance of about 300 km. Reaches 

measured within this stretch were those analyzed in the 

channel width aspect of this study plus those at U.S. 

Geological Survey gaging stations, if not already 

included in the former.

All braiding indices were determined from aerial 

photographs (1938-39 and 1965-69). Islands stabilized

23
Bridgeport North Platte Grand Island

2,000

1,500 

CO EC.

1,000

500

Channel width ca. 1865-1875 

o Channel width ca. 1938 

 Channel width ca. 1962-1972

100 200 300 400 500 

DISTANCE DOWNSTREAM FROM NEBRASKA-WYOMING LINE, IN KILOMETERS

600

FIGURE 17. Channel width at different time periods.

by perennial vegetation show up very clearly on such 

photographs. The length of reach examined was 2 km 

(1 km upstream from the cross section and 1 km 

downstream).

The braiding indices determined here involve only 

those islands located within the main channel. Excluded were islands within the former channel but which, 

on the aerial photograph examined, were essentially 

outside the existing main channel. Such old islands 

usually are surrounded by a distinct paleochannel or 

by a trickle of water. The existing main channel on 

aerial photographs usually is readily identifiable as a 

broad, sandy, generally unvegetated swath.

RESULTS

Table 3, presented earlier, lists all the computed 

braiding indices. Figure 27 shows how these indices 

vary with distance downstream. Nearly all reaches 

sampled are braided to varying extents.

Throughout most of the reach from Lake McConaughy to Grand Island, the river was somewhat 

less braided (had fewer and/ or smaller islands) in 1969 

than in 1938. The chief exception to this tendency is the 

downstream 100 km or so of the reach where the 

braiding either was greater in the 1969 channel or is 

about the same for both time periods.

In 1969, the flow in many channels was only a 

trickle, and the islands were so large relative to this 

small channel that I decided such islands should not be 

considered part of the general watercourse. This 

subjective decision lowers the corresponding braiding 

index and may account for some (but not all) of the 

reduction in braiding index in the pertinent 1969 

channels.

I tried without success to find some relation between 

the changes in braiding and the changes in average 

water discharge (average peaks and average mean 

annual flow) from 1938 to 1969.

24
SINUOSITY

DEFINITION

Sinuosity is the ratio of channel length to valley 

length. Valley length, however, is impractical for use in 

defining the sinuosities of short (2 km) reaches of the 

Platte because the valley is many times as wide as the 

measuring reach. The ideal standard for the Platte, 

rather than valley length, is the length of the original 

(1865) channel as measured midway between the 

banks. This original channel, as shown above, was 

much wider than later channels and is readily identifiable on aerial photographs. In many reaches, it is 

fairly straight or only slightly curving for distances of 

several kilometers or more. Channels which evolved 

later were almost never straighter than the original 

channel in the cases examined. The adapted definition 

of sinuosity (Si) therefore was:

.Length of existing channel 

"Length of original channel

in which channel length was measured midway 

between the banks. This definition actually provides 

the sinuosity of the existing channel relative to that of 

the 1865 channel. In braided reaches, the most 

prominent channel was measured for sinuosity. 

Reaches examined were the same ones analyzed for the 

braiding index described above.

RESULTS

Table 3 gives the data, and figure 28 shows the 

sinuosity changes with distance downstream.

The channel was only slightly more sinuous in 1969 

than in 1938, for most of the study reach. The 

exceptions are: (1) the very beginning of the study 

reach immediately downstream from Kingsley Dam 

and the Sutherland Canal (Keystone) diversion dam, 

which was artificially straightened sometime between 

1938 and 1969, (2) the reach just downstream from the 

Johnson Power Plant return flow (kilometer point 

408), which was straighter in 1969, and (3) the last 50 

km or so (about Gibbon to Grand Island) for which the

0.8

LakeMcConaughy 

(Kingsley Dam)

Johnson Power Plant 

return flow

0.6

0.4

0.2-

I \

\ /

\

100 200 300 400 500 

DISTANCE DOWNSTREAM FROM NEBRASKA-WYOMING LINE, IN KILOMETERS

600

FIGURE 18. Proportion of 1865 width occupied by 1965 channel.

25
data show no particular change from 1938 compared 

to 1969.

The changes in sinuosity from 1938 to 1969 were not 

large enough to show any noticeable relation to the 

respective average water discharges.

BED AGGRADATION AND DEGRADATION

METHOD OF ANALYSIS

A bed elevation for a wide, sandy channel is not a 

precise concept. The shifting nature of small- and 

large-scale bed forms causes a continuous fluctuation 

in the elevation of the bed at any one spot. However, in 

a stable channel, the average bed elevation should be 

reasonably constant if measured over a long enough 

time relative to the passage of bed forms. Changes in 

such a mean bed elevation should reflect a general 

aggradation or degradation.

The method adopted here for estimating the bed 

elevation is far from perfect but is probably the only

method available in view of the historical data. That 

method is to estimate bed elevation using the rating 

curve and gage at U.S. Geological Survey gaging 

stations. (Such gages themselves are nearly always 

surveyed in to elevations above mean sea level.) Bed 

elevation is here taken as the elevation at which zero 

discharge occurs, as indicated by the rating curve (gage 

height versus discharge). This involves extrapolating 

the rating curve to zero discharge, reading the corresponding gage height on the rating-curve graph, and 

finally transferring this gage height into elevation 

above mean sea level.

Besides the uncertainty in equating bed level to the 

level of zero discharge, an unmeasurable amount of 

error stems from extrapolating the rating curve.

With this system, the bed theoretically stays at the 

same level as long as the same rating curve remains in 

effect.

Gaps in the data gathered in this way appear when 

(1) the station was temporarily not in operation, (2) the 

station was moved to another site upstream or

Pre-1899 channel width 1,036 meters

1899 fill reduced channel width to 503 meters

1913 fill reduced channel width to 302 meters

1919 fill reduced channel width to 280 meters

HORIZONTAL SCALE:

150 METERS 1962 width ca. 265 meters

VERTICAL DIMENSION NOT TO SCALE

FIGURE 19. Channel width changes at the Chicago, Burlington, and Quincy (Burlington Northern) Railroad bridge, Platte River, near 

Grand Island, Nebr. Data sources: Chicago, Burlington, and Quincy Railroad channel drawings, 1899-1919; U.S. Geological Survey 

7!4-minute topographic map, 1962, Grand Island Quadrangle.

26
downstream, or (3) the lowest measured discharges 

were sufficiently greater than zero discharge as to 

make an extrapolation to zero too unreliable.

The complete records of the 12 U.S. Geological 

Survey gaging stations within the study reach were 

examined. Most of these records begin in the 

mid-1930's, as mentioned above, which means that 

most stations have records for about the past 40 years. 

(Several stations actually were established around the 

turn of the century but not at the present site. Such 

data were acceptable for the hydrology analysis 

presented earlier but can't be used for present purposes.) Bed elevations, in meters above mean sea level, 

were determined as described above. Relative elevation changes with time were then computed for each 

station to reveal any aggradation or degradation.

RESULTS

Table 4 lists, and figure 29 shows, the data obtained. 

The complex history of water regulation and diversion

upstream from and within the study reach, together 

with the shifting and unstable sand bed, complicate the 

interpretation of the data. Comments will be restricted 

to pointing out major changes in bed elevation with 

time at each station.

From 1936 to 1976 the streambed at the Minatare 

station has gradually degraded. The amount of 

degradation for this period is about 0.7 m.

At Bridgeport the bed eroded about 0.5 m from 1931 

to 1967 but seems to have filled about 0.2 m around 

1967 and has not changed much since.

The Lisco station has remained essentially stable 

since 1933.

The Lewellen station is only about eight kilometers 

upstream from Lake McConaughy. The bed at this 

station (two channels) has aggraded noticeably since 

about the mid-1940's. (Lake McConaughy, formed by 

Kingsley Dam, was created in 1941.) Fill in the north 

channel at Lewellen has amounted to about 0.6 m and 

in the south channel to about 0.3 m.

River shoreline after bridge construction

River shoreline before bridge construction

FIGURE 20. Channel width changes due to bridge, Platte River, 2.4 km south of Kearney. Data from U.S. Dept. Agriculture aerial 

photographs of 1938. Shoreline evolution shown here probably not yet completed.

27
TABLE 4. Basic data for mean bed elevation, in meters above mean sea level, at various time periods

[Gaps in data in most cases mean station was not in operation or too much extrapolation of rating curve needed to estimate gage height of zero flow]

Inclusive dates

Elevation 

(m)

North Platte R nr Minatare

07/21/36-09/30/36 

05/01/37-09/30/37 

05/01/38-09/30/38 

05/01/39-09/30/39 

05/01/40-10/07/40 

06/12/41-09/30/42 

10/01/42-04/30/45 

05/01/45-05/31/47 

06/01/47-07/19/55 

07/20/55-03/21/56 

10/01/65-09/30/67 

10/01/67-06/06/68 

06/07/68-07/31/69 

10/01/69-06/10/70 

06/11/70-06/02/71 

10/01/74-

North Platte R at

10/01/31-04/30/33 

05/01/33-09/30/33 

10/01/33-05/31/34 

06/01/34-09/30/34 

10/01/34-06/30/35 

10/01/35-05/01/37 

05/01/37-09/30/39 

05/01/40- ? 

04/21/41-09/30/41 

10/01/42-09/30/43 

10/01/43-05/31/46 

06/01/46-05/31/47 

06/01/47-05/13/48 

05/14/48-06/07/54 

06/08/54-07/01/56 

07/02/56-09/30/67 

10/01/67-09/30/69 

10/01/69-

North Platte R

9/08/31-04/30/33

1162.42 

1162.42 

1162.42 

1162.26 

1162.26 

1162.19 

1162 . 11 

1162.26 

1162.11 

1162.05 

1161.96 

1162.11 

1162.02 

1162 . 08 

1161.93

Bridgeport

1115.87 

1115.84 

1115.81 

1115.69 

1115.81 

1115.60 

1115.72 

1115.75 

1115.66 

1115.60 

1115.69 

1115.75 

1115.75 

1115.42 

1115.57 

1115.35 

1115.63 

1115.60

at Lisco

1059.58

Inclusive dates

North Platte R at 

Continued

Elevation 

(m)

Lisco

10/01/33-03/31/37 1059.39 

10/01/37-03/31/40 1059.42 

04/01/40-09/30/42 1059.39 

10/01/42-06/28/55 1059.33 

06/29/55-09/30/63 1059.39 

10/01/63-09/30/67 1059.45 

10/01/67-06/18/70 1059.39 

06/03/71-06/11/73 1059.26 

05/29/74- 1059.48

North Platte R nr Lewellennorth channel

11/30/40-09/30/42 1001.82 

10/01/42-05/31/54 1001.57 

06/01/54-09/30/58 1001.73 

10/01/58-09/30/61 1001.85 

10/01/61-09/30/64 1001.91 

10/01/64-09/30/67 1001.97 

10/01/67-05/04/69 1002. Ofi 

05/05/69-02/12/70 1002.06 

02/13/70-06/04/71 1002.18

North Platte R nr Lewellensouth channel

11/30/40-09/30/42 

10/01/42-06/30/50 

07/01/50-07/27/54 

07/28/54-09/30/58 

10/01/58-09/30/64

North Platte R nr

05/12/45-06/30/45 

07/01/45-09/30/45 

10/01/45-04/29/49 

04/30/49-11/04/50 

11/05/50-05/31/51 

06/01/51-09/30/51 

10/01/51-09/30/52

1001.48 

1001.45 

1001.54 

1001.69 

1001.79

Keystone

947.32 

947.50 

947.47 

947.11 

947.14 

947.01 

946.86

Inclusive dates

Elevation 

(m)

North Platte R nr Keystone 

Continued

10/01/52-02/04/53 

02/05/53-04/14/54 

04/15/54-06/11/54 

10/01/55-02/28/56 

02/29/56-09/30/57 

10/01/57-06/30/58 

05/01/62-10/31/63 

11/01/63-09/30/67 

03/02/68-03/03/70 

03/04/70-05/18/71 

11/27/71-03/07/72 

03/08/72-09/30/72 

10/01/72-05/09/74

North Platte R nr

10/01/36-12/12/40 

12/13/40-10/01/42 

10/02/42-03/31/53 

04/01/53-03/14/56 

03/15/56-08/27/56 

03/07/57-09/30/58 

10/01/58-10/24/67 

10/25/67-05/06/68 

05/07/68-04/08/69 

04/09/69-07/22/69 

07/23/69-09/30/69 

10/01/69-06/07/71

North Platte R at

10/01/31-09/30/33 

10/01/33-03/31/37 

04/01/37-09/30/38 

10/01/38-04/03/40 

04/23/40-07/13/41 

07/14/41-09/30/42 

10/01/42-06/30/44 

07/01/44-05/31/46 

07/01/46-10/31/47

946.77 

946.80 

947.07 

946.92 

946.98 

947.01 

946.89 

946.77 

946.98 

947.03 

947.03 

947.11 

947.20

Sutherland

892.32 

892.29 

892.18 

892.00 

892.06 

892.09 

891.94 

891.88 

891.83 

891.81 

891.88 

891.84

North Platte

851.49 

851.55 

851.40 

851.64 

851.46 

851.43 

851.55 

851.40 

851.34

Elevation 

Inclusive dates

(m)

North Platte R at North Platte 

Cont inued

11/01/47-09/30/57 

02/28/65-09/30/67

Platte R at Brady No.

03/01/.39-09/30/42 

10/01/42-03/31/43 

04/01/43-04/30/45 

05/01/45-06/15/49 

06/16/49-04/30/52 

05/01/52-08/04/53 

08/05/53-05/10/55 

05/11/55-02/27/56 

02/28/56-05/27/56 

05/28/56-09/30/56 

10/01/56-05/15/57 

05/16/57-05/31/59 

06/01/59-06/21/65 

06/25/65-09/30/67 

10/01/67-06/24/69 

06/25/69-02/20/-70 

08/07/70-02/27/71 

02/28/71-07/05/71 

07/06/71-09/30/72 

10/01/72-06/05/73 

10/01/73-

Platte R at Brady-So.

03/08/39-09/30/40 

10/01/40-09/30/41 

10/01/42-02/04/49 

02/05/49-04/30/51 

05/01/51-04/30/59 

05/01/59-09/30/61 

10/01/61-06/23/65 

06/24/65-09/30/67 

10/01/67-04/27/70 

04/28/70-09/30/70 

10/01/70-06/20/71

851.40 

851.37

channel

804.98 

804.92 

804.73 

804.89 

804.67 

804.73 

804.95 

805.10 

804.85 

805.10 

804.92 

805.04 

804.92 

804.66 

804.67 

804.70 

804.92 

804.85 

804.55 

804.52 

804.53

channel

805.34 

805.28 

805.22 

805.07 

805.13 

805.22 

805.25 

805.19 

805.25 

805.28 

805.22

28
TABLE 4. Basic data for mean bed elevation Continued

Elevation 

Inclusive dates 

(m)

Platte R at Brady So.

Continued

06/21/71-05/12/73

05/16/73-

Platte R nr Cozad No.

10/01/40-09/30/42

10/01/42-03/21/43

03/22/43-05/31/47

06/01/47-04/30/48

05/01/48-06/22/49

06/23/49-05/01/55

10/01/55-06/30/57

07/01/57-04/24/63

04/25/63-03/31/68

04/01/68-06/16/70

06/17/70-10/05/70

10/06/70-06/15/71

06/16/71-02/04/72

02/05/72-09/30/72

10/01/72-05/15/73

05/16/73-09/30/74

10/01/74-

Platte R nr Cozad So.

10/01/40-09/30/42

10/01/42-03/31/43

04/01/43-06/21/47

06/22/47-04/02/48

04/07/48-06/23/49

06/24/49-03/31/50

04/01/50-09/30/50

10/01/50-09/30/53

10/01/53-05/01/55

05/02/55-09/30/56

10/01/56-05/14/57

05/15/57-03/24/58

05/26/58-09/30/59

10/01/59-02/25/63

02/26/63-05/03/65

.channel

805,19

805.22

channel

755.45

755.26

755.48

755.23

755.26

755.20

755.14

755.26

754.96

755.08

754.90

754.87

754.90

754.87

754.90

754.84

754.90

channel

755.36

755.26

755.17

754.59

754.81

754.26

754.47

754.72

754.90

754.75

754.68

754.11

754.87

754.84

754.62

Elevation 

Inclusive dates 

(m)

Platte R nr Cozad So. channel

Continued

05/04/65-06/22/65

06/23/65-02/12/66

02/13/66-09/30/67 

10/01/67-09/30/68

05/17/69-02/03/70

02/04/70-06/22/70

06/23/70-08/10/70

08/11/70-02/11/71

02/12/71-04/12/71

04/13/71-station moved

Platte R nr Overton

South channel

01/01/31-11/30/31

02/28/32-05/12/33

05/13/33-03/31/36

04/01/36-04/15/38

04/16/38-09/30/41

10/01/41-09/30/43

10/01/43-09/30/46

10/01/46-05/31/48

06/01/48-05/31/49

06/01/49-09/30/52

10/01/52-08/16/55

05/20/57-09/30/57

10/01/58-06/23/65

05/07/66-01/31/67

02/01/67-07/31/68

Platte R nr Odessa

10/01/38-09/30/40

10/01/40-03/23/42

10/01/42-09/30/43

10/01/43-05/31/46

06/01/46-04/30/48

05/01/48-03/31/56

04/01/56-07/02/65

05/08/66-09/30/67

754.41

754.20

754.01 

754.17

754.01

754.14

753.89

753.92

753.95

701.53

701.59

701.53

701.41

701.50

701.44

701.53

701.56

701.53

701.28

701.41

701.22

701.19

701.19

701.25

670.07

670.16

669.98

670.29

670.19

670.10

670.04

670.04

Inclusive dates

Elevation 

(m)

Platte R nr Odessa Continued

01/27/68-02/07/70

02/08/70-05/05/71

07/02/71-05/26/72

05/27/72-05/21/73

10/01/73-

Platte R nr Grand

06/01/35-09/30/35

10/01/35-09/30/39

10/01/39-09/30/40

03/18/41-09/30/43

10/01/44-09/30/51

10/01/51-03/28/60

03/29/60-09/30/60

05/22/61-09/30/62

10/01/62-06/22/65

06/23/65-09/30/66

06/07/67-05/22/70

05/23/70-03/11/71

03/12/71-06/30/71

04/18/72-06/21/73

06/22/73-07/26/73

05/29/74-06/30/76

669.95

669.89

669.86

669.89

669.89

Island

558.82

558.88

558.91

558.97

558.91

558.79

558.82

558.82

558.88

558.82

558. 82

558.67

558.82

558.82

558.67

558.67

29
1860 1900 1940

YEAR

FIGURE 21. Historical trends of annual peak flows, mean annual flows and channel width. North Platte River at North Platte.

The gaging station near Keystone is located just 

downstream from Kingsley Dam and from the diversion dam of the Sutherland Reservoir supply canal, 

which began operation in November 1937. The station 

has been at its present site since mid-1944. During the 

10 years from 1944-54, the bed scoured about 0.6-0.8 

m. (The channel had also been degrading during the 

previous several years, according to U.S. Geological 

Survey notes.) The bed level fluctuated over a range of 

about 0.2 m from the mid-1950's until the late 1960's. 

Since the late 1960's, it seems to have gradually 

aggraded about 0.4 m.

The channel of the North Platte near Sutherland has 

gradually eroded approximately 0.5 m since about 

1940.

At North Platte the riverbed elevation seems to have 

been fairly stable over the past 45 years.

The North Platte at Brady today flows mainly in two 

channels. The bed level in the north channel has 

undergone periodic fluctuations of several tenths of a 

meter during the period of record (1939-present). 

Today (1977) the bed is about 0.5 m lower than it was 

in 1939-40. The south channel scoured about 0.3 m 

from 1939-49, then regained 0.1-0.2 m of this over the

30
CHANNEL WIDTH, IN METERS 

to *> o

000

o o o

T

J_

b b

o o

o o

CHANNEL WIDTH, IN FEET

CHANN
55°

0)

o

CHANNEL WIDTH, IN METERS

01 o bi

o o o

o o o

AVERAGE MEAN

ANNUAL FLOW,

IN M 3 /SEC

O

P1%r

<O

0° ."

o 

o 

o

CHANNEL WIDTH, IN FEET

0) O

b 

o 

o

NJ

b 

o 

o

AVERAGE MEAN

ANNUAL FLOW,

IN FT3 /SEC
AVERAGE ANNUAL PEAK FLOW, IN CUBIC FEET PER SECOND 

10,000 20,000

600

f 400

h 

Q

111

Z

< 200

I

1950-54

1955-59^1960-64 

1965-69

4,000

I 

h 

Q

§

2,000 ill

Z 

Z

<

I

O

200 400 600 

AVERAGE ANNUAL PEAK FLOW, IN CUBIC METERS PER SECOND

FicuRb 25. Relation of channel width to 5-year-averaged annual peak flows, Platte River near Overton.

1,200

600

AVERAGE MEAN ANNUAL FLOW, IN CUBIC FEET PER SECOND

2,000 4,000

'1915-19 

"1920-24

1925-29

1930-34

^1935-39

1955-59!

\

1965-69

'1940-44

945-49 

950-54 

1960-64

40 80 

AVERAGE MEAN ANNUAL FLOW, IN CUBIC METERS PER SECOND

120

4,000

2,000

Fici'Rt 26. Relation of channel width to 5-year-averaged mean annual flows, Platte River near Overton.

33
250 300 350 400 450 500 

DISTANCE DOWNSTREAM FROM NEBRASKA-WYOMING LINE, IN KILOMETERS

550

FIGURE 27. Changes in braiding index with distance downstream.

(1940-present). The north channel has degraded about 

0.7 m, the south channel about 1.5 m. The latter 

degradation represents the largest amount of change of 

the 12 stations studied.

The Platte River near Overton was reasonably 

stable from 1930-49. From 1949-57 it scoured about 

0.3 m and has remained at about that same elevation 

since.

Near Odessa the bed of the river has fluctuated 

about ±0.2 m since 1938.

At Grand Island the river bed has been fairly stable, 

fluctuating within ±0.1 m since 1936.

The various and inconsistent changes of bed elevation with time mean that the gradient of the river bed 

has also changed with time in a similarly complex way.

The same is true of the channel depth, although any 

changes have not been very large.

CONCLUSIONS

The channels of the North Platte and Platte Rivers 

in western and central Nebraska have changed considerably since about 1865.

The changes are most pronounced in the upstream 

365 km of the study reach (Minatare to Overton). 

Within this reach, the channel in 1969 (and 1977) was 

only about 0.1-0.2 as wide as the 1865 channel. A 

significant part of this reduction in width has occurred 

since 1940. In the downstream 150 km of this reach, a 

reduction in braiding and a minor increase in sinuosity

34
1.30

1.25

1.20

>- 1.15

C/5

1.10

1.05

1.00

0.95

01938

 1965-69

c Same value for both 1938 and 1965-69

"200 250 300 350 400 450 500 

DISTANCE DOWNSTREAM FROM NEBRASKA-WYOMING LINE, IN KILOMETERS

550

Fici'Rfc 28. Changes in channel sinuosity with distance downstream.

have taken place between 1938 and 1969. From 

Overton to Grand Island (a distance of about 115 river 

km) the channel in 1969-77 was about 0.6-0.7 as wide 

as it was in 1865. The 1969 channel in some reaches was 

more braided than in 1938, and for other reaches there 

was no significant change. Sinuosity was a little greater 

in 1969 than in 1938 for about the first 40 or 50 km of 

this reach, but in the remaining distance to Grand 

Island the degree of sinuosity was about the same in 

both 1938 and 1969.

Over the entire 480-km reach, vegetation, including 

many trees, has become firmly established in the part 

of the former channel which now carries no water.

Since about 1935-40 the estimated mean bed elevation has fluctuated at the 12 U.S. Geological Survey 

gaging stations along the 480-km study reach. These 

fluctuations probably reflect the complex regulation of 

water and sediment delivery to the river.

In the absence of any significant climatic shifts, the 

various channel changes described above most likely

35
0.0 

-0.1 

-0.2 

-0.3

-0.4' 

-0.5 

-0.6

-0.7

0.0

co -°' 1 

cc LU -0.2

111

^ -0.3 

^ -0.4

(ARBITRARY DATUM

I 

oo b L.(D Ul

Z -0.2 

0 

h- -0.3

w -0.4

_i 

m

2 +0.4 

m 

+0.3

+ 0.2 

+0.1 

0.0

-0.1 

-0.2 

-0.3

+0.3 

+ 02 

+0.1 

0.0

-0.1 

19

;

-

-

-

-

North Platte

North Platte

North Platte 

North Platte

North Platte

 

River near M

River at Bridg

River at Lisco 

River at Lewe

River at Lewe

natare

eport (main c

lien (north ch

Men (south ch

lannel)

annel)

 

 

-

 

-

;

-

__

-

-

-

30 1935 1940 1945 1950 1955 1960 1965 1970 1975

YEAR »-

FIGURE 29. Changes in bed elevation during the past 45 years at 12 U.S. Geological Survey gaging stations within the study reach. Dashed

reterence line drawn at earliest known elevation.

36
II + +

P o P o p

NS L> O LJ NJ

I '
0.0 

-0.1

-0.2 

-0.3 

-0.4

0.0 

-0.1

-0.2 

-0.3 

-0.4 

£ -0.5

LU

fcj -0.6

I -°'7

H: -0.8 

^ 

=> -0.9

Q -1.0

£ -1.1 

<

fE -1.2

oc -1.3 

< 

z -1.4

O

25 °-° 

^ -0.1

Q 

£ -0.2

-0.3

+0.2 

+0.1 

0.0 

-0.1 

-0.2

+0.1 

0.0 

-0.1

-

- Plait

-

_ Plait 

Platt

Platt

- Platt

e River near C

e River near C 

3 River Overtc

3 River near C

e River near C

:ozad (north c

 

)ozad (south c 

n (south char

dessa

 ^~

Brand Island

tannel)

hannel) 

nel)

 

~ _

-

-

-

-

1930 1935 1940 1945 1950 1955 

YEAR 

19601 1965 1970 ,1975

FIGURE 29. Changes in bed elevation Continued 

38
are due to the rather systematic decrease in water 

discharge (and possibly sediment discharge) that has 

occurred. If this is the case, the changes agree 

qualitatively with the theoretical predictions of 

Schumm (1969). The decrease in water discharge (both 

peak flows and mean annual flows) probably is due to 

the creation of on-stream reservoirs and the greater 

consumptive use of river water.

REFERENCES

Bentall, Ray, 1975, Hydrology, Nebraska Mid-State Division and

associated areas: Nebraska Univ. Conserv. and Survey Div.,

Inst. Agriculture and Nat. Resources Rept., 256 p. 

Brice, J. C., 1964, Channel patterns and terraces of the Loup Rivers

in Nebraska; U.S. Geol. Survey Prof. Paper 422-D, 41 p. 

Bunde, Michael and others, 1975, The effects of the selective removal

of cottonwood trees along the Platte River: Natl. Sci. Found.

study, Dept. Biology, Kearney State College, 200 p. 

Clayton, W., 1848, the Latter-Day Saints1 emigrants' guide: St.

Louis, Chambers and Knapp, 24 p. 

Farrar, Jon, 1975, Crane river: NEBRASKAland Mag., March

1975, p. 18-35.

Fremont, J. C., 1843, A report on an exploration of the country lying

between the Missouri River and the Rocky Mountains on the

line of the Kansas and Great Platte Rivers: 27th Cong., 3rd

Session, Senate Doc. 243 (Serial 416), 207 p. 

Frith, C. R., 1974, The ecology of the Platte River as related to

sandhill cranes and other waterfowl in south central Nebraska:

M.S. thesis, Kearney State College, 115 p. 

McKinley, J. L., 1938, The influence of the Platte River upon the

history of the valley: Lincoln, Univ. Nebraska, Ph. D. thesis,

138 p. 

Nebraska State Board of Irrigation, Highways, and Drainage, 1914,

Tenth Biennial Report: University Place, Nebraska, Claflin

Publishing Co., 356 p. 

Rollins, P. A., ed., 1935, The discovery of the Oregon Trail Robert

Stuart's narratives: New York, Scribner's Sons, 391 p. 

Ruby, E. S., 1952, Forage production of North Platte River islands:

Jour. Range Management, v. 5, no. 2, p. 84-89. 

Schumm, S. A., 1969, River metamorphosis: Am. Soc. Civil

Engineers Proc., Jour. Hydraulics Div., v. 95, no. HY1, p.

255-273. 

Sutherland, D. M., 1974, Identification and evaluation of present

vegetative resources Nebraska Mid-State Division

Pick-Sloan Missouri Basin program and associated areas:

prepared for U.S. Bureau Reclamation, Lower Missouri

Region, by Univ. Nebraska-Omaha, 102 p.

39
TABLE 5. Historical discharge data for North Platte and Platte gaging stations within the study reach

[All data are for water years October l-September 30]

Year

1895-96 

1897 

1898 

1899 

1900 

1901 

1902 

1903 

1904 

1905 

1906 

1907 

1908 

1909 

1910-14 

1915 

1916 

1917 

1918 

1919 

1920 

1921 

1922 

1923 

1924 

1925 

1926 

1927 

1928 

1929 

1930

1QT1

Maximum

Flow 

(m3 /s)

 

 

 

736 

793

147 

552 

249 

113

680 

289 

331 

459 

215 

227 

198 

416 

481 

266 

im

MINATARE

discharge Mean Number

Date annual of 

discharge no-flow 

(m3 /s) days

 

_____

______

06/04/08 

06/04/09

07/16/16 

07/02/17 

06/25/18 59 

09/14/19

06/18/21 

05/20/22 

09/30/23 

04/17/24 84 0 

05/18/25 45 0 

06/19/26 62 0 

06/23/27 69 0 

06/06/28 73 0 

06/03/29 80 0 

10/01/29 49 0 

in/n7/ln T.T. n

BRIDGEPORT LISCO

Maximum

Flow 

(m3 /s)

643 

481 

705 

411

187 

306 

402 

515 

578

171 

125 

572 

278 

130 

329 

680 

215 

227 

396 

283 

218 

221 

425 

680 

263 

i -»n

discharge

Date

06/06/97 

05/28/98 

06/26/99 

06/05/00

06/07/02 

06/23/03 

06/09/04 

06/15/05 

05/29/06

06/10/15 

06/16/16 

06/26/17 

06/27/18 

09/13/19 

05/15/20 

06/19/21 

05/22/22 

05/25/23 

04/18/24 

05/19/25 

06/16/26 

06/23/27 

06/06/28 

06/03/29 

10/01/29 

i n/n7/<in

Mean Number Maximum discharge Mean Number

annual of Flow Date annual of 

discharge no-flow discharge no-flow 

(m 3 /s) days (m3 /s) (m3 /s) days

_______

69 _ ________

HO - _______

170 05/22/16 

101 - 569 06/27/17 

67 - ________

43 _ ________ 

79 - 

77 __ _. __ _____ __ . __ __ __ _

54 _ ________

TO __ __ _.

91 _ ________

A"? n _ _ 

40
TABLE 5. Historical discharge data Continued

MINATARE

Year

1932

1933

1934

1935

1936

1937

1938

1939

1940

1941

1942

1943

1944

1945

1946

1947

1948

1949

1950

1951

1952

1953

1954

1955

1956

1957

1958

1959

1960

1961

1962

1963

Maximum

Flow 

(m3 /s)

60

180

56

258

50

111

84

49

61

129

197

57

65

95

61

191

91

84

60

89

129

103

48

267

95

109

148

40

41

37

96

106

discharge

Date

08/03/32

05/25/33

10/06/33

06/02/35

06/09/36

07/15/37

05/20/38

06/16/39

06/06/40

06/11/41

05/14/42

04/01/43

05/17/44

06/11/45

10/01/45

06/26/47

06/17/48

06/13/49

09/19/50

06/25/51

06/22/52

06/07/53

05/22/54

06/28/55

07/03/56

05/20/57

06/09/58

09/30/59

10/01/59

05/15/61

06/30/62

05/30/63

Mean 

annual 

discharge 

(mVs)

26

35

19

17

15

19

25

19

15

16

29

24

23

29

25

32

28

27

24

26

34

25

16

15

13

19

20

17

15

14

19

17

Number 

of 

no- flow 

days

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Maximum

Flow 

(m 3 /s)

62

186

69

351

62

100

138

50

50

153

286

70

71

121

80

239

91

79

76

133

120

106

45

236

196

119

138

63

64

51

91

113

BRIDGEPORT

discharge

Date

08/04/32

05/26/33

10/02/33

06/02/35

06/09/36

07/16/37

09/05/38

11/03/38

06/07/40

06/12/41

05/15/42

04/03/43

06/12/44

06/12/45

10/02/45

06/30/47

06/17/48

06/14/49

09/20/50

09/04/51

06/01/52

06/08/53

10/21/53

06/29/55

07/03/56

05/20/57

07/18/58

09/28/59

10/01/59

07/31/61

07/14/62

06/14/63

Mean 

annual 

discharge 

(m3 /s)

33

44

26

23

21

24

33

26

21

21

38

33

33

41

33

41

38

37

33

37

42

34

22

21

19

27

28

25

22

20

28

26

Number 

of 

no-flow 

days

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Maximum

Flow 

(m3 /s)

60

231

101

343

74

95

162

61

59

145

240

78

88

123

83

221

89

91

80

145

108

103

51

167

115

112

91

61

65

46

94

89

LISCO

discharge

Date

06/18/32

05/26/33

05/03/34

06/15/35

06/10/36

07/18/37

04/26/38

11/03/38

06/08/40

06/13/41

05/16/42

10/14/42

07/11/44

06/13/45

10/02/45

06/29/47

06/18/48

06/15/49

09/19/50

09/04/51

06/03/52

07/30/53

10/21/53

07/01/55

07/05/56

05/21/57

07/22/58

09/26/59

10/02/59

05/14/61

07/15/62

06/16/63

Mean 

annual 

discharge 

(m3 /s)

35

48

29

25

22

27

38

30

23

24

44

37

37

43

36

44

42

40

36

41

45

38

25

23

21

30

33

28

24

22

30

29

Number 

of 

no flow 

days

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

41
TABLE 5. Historical discharge data Continued

MINATARE

Year

1964 

1965 

1966 

1967 

1968 

1969 

1970 

1971 

1972 

1973 

1974 

1975 

1976

Maximum discharge

Flow Date 

(mVs)

50 06/22/64 

131 06/18/65 

38 10/19/65 

97 06/07/67 

110 06/16/68 

43 04/13/69 

124 06/17/70 

422 06/02/71 

79 03/20/72 

245 05/27/73 

157 04/03/74 

54 07/05/75

Mean 

annual 

discharge 

(mVs)

15 

24 

18 

22 

23 

19 

26 

67 

33 

69 

54 

24 

23

Number 

of 

no- flow 

days

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

LEWELLEN

Year

1895-1916 

1917 

1918-32 

1933 

1934 

1935 

1936 

1937 

1938 

1939 

1940 

1941 

1942 

1943 

1944 

1945

Maximum discharge

Flow Date 

(m3 /s)

______

_______

140 06/14/41 

237 05/16/42 

80 03/12/43 

94 07/12/44 

137 06/16/45

Mean 

annual 

discharge 

(m3 /s)

~

-

48 

41 

40 

48

Number 

of 

no-flow 

days

0 

0 

0 

0

BRIDGEPORT

Maximum discharge

Flow Date 

(mVs)

58 10/01/63 

170 06/24/65 

64 10/01/65 

120 06/15/67 

113 06/17/68 

78 05/05/69 

154 06/18/70 

464 06/03/71 

89 06/25/72 

297 05/28/73 

170 03/18/74 

66 06/30/75

Mean 

annual 

discharge 

(mVs)

24 

34 

30 

33 

34 

28 

38 

82 

43 

82 

61 

31 

29

Number 

of 

no-flow 

days

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

Maximum

Flow 

(mVs)

65 

161 

69 

112 

90 

77 

131 

374 

91 

274 

170 

61

KEYSTONE

Maximum discharge

Flow Date 

(m3 /s)

575 06/30/17

 

74 08/03/42 

61 08/04/43 

105 07/31/44 

75 07/30/45

Mean 

annual 

discharge 

(mVs)

 

 

11 

8.1 

12

Number 

of 

no- flow 

days

-

-

0 

0 

0

Maximum

Flow 

(m3 /s)

575 

283 

340

86 

107 

91 

55 

40 

65 

55 

70 

57

LISCO

discharge

Date

10/21/63 

06/11/65 

10/19/65 

06/16/67 

06/18/68 

05/06/69 

06/20/70 

06/03/71 

03/21/72 

05/29/73 

04/08/74 

07/01/75

Mean 

annual 

discharge 

(mVs)

26 

38 

33 

35 

36 

31 

38 

77 

45 

85 

64 

35 

32

Number 

of 

no- flow 

days

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0

SUTHERLAND

discharge

Date

06/29/17 

05/29/33 

06/18/35

03/07/37 

04/29/38 

03/12/39 

03/01/40 

07/28/41 

09/02/42 

07/23/43 

08/24/A4 

08/02/45

Mean 

annual 

discharge 

(mVs)

 

21 

40 

21 

13 

3.5 

5.3 

10 

7.9 

14

Number 

of 

no-flow 

days

0 

0 

0 

9 

0 

0 

0 

0 

0

42
TABLE 5. Historical discharge data Continued

LEWELLEN

Year

1946

1947

1948

1949

1950

1951

1952

1953

1954

1955

1956

1957

1958

1959

1960

1961

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

1973

1974

1975

1Q7fi

Maximum

Flow 

(m3 /s)

87

259

102

92

97

159

114

93

63

147

136

108

150

65

101

61

99

85

79

144

85

108

113

79

133

382

142

277

173

65

discharge

Date

10/03/45

06/29/47

02/19/48

06/16/49

08/06/50

09/06/51

06/04/52

06/10/53

10/21/53

07/02/55

07/06/56

05/22/57

07/20/58

01/27/59

03/19/60

05/22/61

07/17/62

06/02/63

10/21/63

06/12/65

10/19/65

06/17/67

05/06/68

05/07/69

06/22/70

06/04/71

06/26/72

05/27/73

04/11/74

04/28/75

Mean 

annual 

discharge 

(m3 /s)

39

49

45

44

41

46

49

40

28

25

23

32

36

30

27

24

34

31

28

40

35

37

38

33

41

80

47

87

66

38

T5

Number 

of 

no-flow 

days

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0 

n

Maximum

Flow 

(m'/s)

75

89

88

86

47

58

104

88

80

69

81

64

114

75

70

81

104

87

81

50

86

67

103

63

91

251

88

216

117

86

KEYSTONE

discharge

Date

07/22/46

08/18/47

07/28/48

07/26/49

10/10/49

08/12/51

07/04/52

07/06/53

07/29/54

08/09/55

07/17/56

08/07/57

07/02/58

07/21/59

07/24/60

07/17/61

05/16/62

07/09/63

07/04/64

08/18/65

07/13/66

07/26/67

08/09/68

07/16/69

06/19/70

06/10/71

05/15/72

06/03/73

03/28/74

07/30/75

Mean 

annual 

discharge 

(m3 /s)

12

9.2

13

9.9

9.0

6.6

27

11

9.9

10

9.4

8.8

4.8

8.9

8.7

8.1

5.0

10

9.1

5.7

9.1

9.2

12

12

11

38

20

43

38

11 

is

Number 

of 

no-flow 

days

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

194 

lis

Maximum

Flow 

(m3 /s)

57

84

86

73

42

35

87

67

59

56

52

56

115

60

60

59

95

72

58

50

71

54

86

55

80

257

82

195

110

68

SUTHERLAND

discharge

Date

07/24/46

08/20/47

07/29/48

07/28/49

05/06/50

05/15/51

06/10/52

07/09/53

07/20/54

07/28/55

07/19/56

07/22/57

08/17/58

07/21/59

08/09/60

07/19/61

05/17/62

07/11/63

07/09/64

08/21/65

07/15/66

07/28/67

08/11/68

07/22/69

06/21/70

0*6/08/71

05/16/72

06/12/73

03/21/74

07/31/75

Mean 

annual 

discharge 

(m 3 /s)

12

10

12

11

10

8.9

27

10

8.7

9.7

8.0

9.3

6.6

8.5

9.3

8.4

6.7

10

9.1

6.7

10

9.3

11

11

10

38

20

41

37

11 

18

Number 

of 

no-flow 

days

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0 

n

43
TABLE 5. Historical discharge data Continued

Year

1 RQ^

1896

1 QO7

1898 

1899

1900

1901

1902

1903

i on&

1910

1911

1913

1914

1 O1 £

1 O1 Q

1919

1920

1922

1923

1924 

1925

1926

Maximum

Flow 

(m3 /s)

493

708

433

C1 0

549

549

ORn

453

470

453

756

195

101

309

592

OUT

122

425

297

524

1 7Q

106

NORTH

discharge

Date

06/07/95

06/08/97

05/30/98 

06/27/99

03/16/03

06/16/05

06/05/06

06/16/07 

06/04/08

06/11/09

10/16/09 

02/13/11

10/14/12

05/03/14

05/27/15

06/30/18

06/09/19

06/25/20

06/20/21

05/29/23

10/03/23 

05/21/25

06/19/76

PLATTE

Mean Number

annual of 

discharge no-flow 

(m3 /s) days

132

71 

152

91

76

61

Q 1

71

114

105

112

64

44

39

103

O1

57

59

64

i no

105

77

71

118 

74

1 m

BRADY COZAD

Maximum discharge Mean Number Maximum discharge Mean Number

Flow Date annual of Flow Date annual of 

discharge no-flow discharge no-flow 

(m 3 /s) (m 3 /s) days (m3 /s) (m3 /s) days

 _ 

 _ 

44
TABLE 5. Historical discharge data Continued

Year

1927

1929

1932

1934

1936

1937

1938

1940

1941

1942

1943

1944

1945

1946

1947

1948

1949

1950

1951

1952

1953 

1954

1955

1956

1957

1958

Maximum

Flow 

(m 3 /s)

592

312

195

179

0 QT

331

142

66

45

187

69

71

75

58

74

95

73

54

153

86

71

61

61

60

56

105

NORTH

discharge

Date

08/08/27

06/12/28

10/04/29

04/03/31

06/18/35

02/24/37

04/29/38

06/07/40

07/29/41

09/03/42

06/15/43

08/25/44

08/05/45

07/22/46

08/21/47

07/29/48

08/02/49

05/06/50

05/15/51

06/11/52

07/10/53

07/21/54

08/09/55

06/18/56

07/23/57

08/18/58

PLATTE

Mean 

annual 

discharge 

(mVs)

102

75

55

64

22

27

46

OQ

17

9.4

13

17

14

21

19

17

19

18

17

17

34

17

15

15

15

17

14

Number 

of 

no-flow 

days

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Maximum

Flow 

(m 3 /s)

193

246 

82

48

436

67

52

44

34

295

87

411

26

193

129

53

47

44

71

185

141

BRADY

discharge Mean

Date annual 

discharge 

(m 3 /s)

09/14/38 

03/03/40 27

12/03/40 7.7

05/07/42 38

06/16/43 10

05/16/44 7.6

08/22/45 8.1

07/25/46 7.3

07/01/47 16

02/17/48 11

06/22/49 24

07/22/50 5.4

05/16/51 11

03/25/52 25

07/10/53 9.1

07/23/54 7.6

07/21/55 8.9

06/19/56 7.5

05/24/57 12

06/04/58 14

COZAD

Number 

of 

no-flow 

days

-

0

3

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Maximum

Flow 

(m 3 /s)

204

156

39

470

119

56

57

16

343

103

385

67

174

93

22

15

17

52

176

133

discharge

Date

09/15/38

06/09/40

11/22/40

05/10/42

06/28/43

05/12/44

06/10/45

01/11/46

06/23/47

07/29/48

06/23/49

11/11/49

05/17/51

03/26/52

01/09/53

02/01/54

03/11/55

06/20/56

05/25/57

05/26/58

Mean Number 

annual of 

discharge no-flow 

(m 3 /s) days

 

19

7.2

38 0

8.1 0

7.2 0

7.6 0

5.3 0

17 0

10 0

23 0

9.1 0

11 0

21 0

5.5 0

4.4 0

4.8 0

4.0 0

9.3 0

14 0

45
TABLE 5. Historical discharge data Continued

Year

1959

1960

1961

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

1973

1974

1975

1976

NORTH

Maximum discharge

Flow

(mVs)

59

59

58

100

71

72

54

79

71

90

61

84

271

94

196

124

85

Date

07/22/59

08/10/60

07/22/61

05/18/62

07/13/63

07/10/64

08/22/65

06/09/66

07/09/67

08/12/68

07/24/69

06/24/70

06/10/71

05/12/72

06/13/73

04/13/74

08/01/75

PLATTE

Mean

annual

discharge

(m3 /s)

14

16

14

14

17

15

14

17

16

18

18

17

44

26

49

46

17

24

BRADY

Number

of

no-flow

days

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Maximum

Flow

(m 3 /s)

40

74

88

69

55

59

476

58

112

91

186

226

360

88

527

180

68

OVERTON

Year

1895-1914

1915

1 Q1 fl

1922

Maximum

Flow

(mVs)

555

609

266

discharge

Date

05/29/15 

05/24/16

05/18/20

05/23/22

Mean

annual

discharge

(m 3 /s)

119

173

Oo

66

139

79

Number

of

no-flow

days

.__

Maximum

Flow

(mVs)

discharge

Date

08/05/59

03/23/60

08/17/61

05/19/62

07/12/63

07/11/64

06/23/65

07/19/66

07/09/67

08/20/68

06/29/69

06/24/70

06/10/71

05/13/72

05/14/73

03/21/74

08/02/75

Mean Number

annual of

discharge no-flow

(m3 /s) days

7.6 0

9.6 0

10 0

7.9 0

11 0

8.5 0

13 0

11 0

11 0

8.2 0

13 0

19 0

57 0

19 0

74 0

57 0

10 0

11 0

ODESSA

discharge

Date

________

Mean Number

annual of

discharge no-flow

(m'/s) days

____

COZAD

Maximum discharge

Flow Date

(m'/s)

23 05/21/59

103 03/23/60

57 08/18/61

117 06/08/62

41 02/05/63

28 04/27/64

447 06/24/65

61 03/01/66

101 07/10/67

43 08/20/68

173 06/30/69

220 06/25/70

357 06/11/71

82 05/13/72

521 05/29/73

179 03/20/74

46 06/22/75

Mean

annual

discharge

(m 3 /s)

5.7

8.5

7.4

9.5

7.5

6.4

13

8.8

9.1

5.2

10

15

51

16

72

55

6.6

5.6

Number

of

no-flow

days

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

GRAND ISLAND

Maximum discharge

Flow Date

(m'/s)

_._

Mean

annual

discharge

(m 3 /s)

_____

Number

of

no-flow

days

.

-__

46
TABLE- 5. Historical discharge data Continued

OVERTON

Year

1925

1929

1930

1934

1935

1937

1938

1939

1940

1941

1942

1943

1944

1945

1946

1947

1948

1949

1950

1951

1952

1953

1954

1955

1956

Maximum

Flow 

(m 3 /s)

623

362

651

538

909

173

173

200

217

274

253

66

430

109

115

157

99

530

170

428

91

214

162

131

83

67

56

discharge

Date

06/17/23

04/19/27

05/13/30

03/18/32

02/01/34

06/05/35

03/20/37

02/28/38

03/18/39

03/02/40

03/16/41

05/10/42

04/12/43

05/12/44

06/11/45

03/16/46

06/23/47

06/23/48

06/24/49

11/14/49

05/18/51

03/27/52

01/09/53

11/06/53

03/10/55

03/31/56

Mean 

annual 

discharge 

(m3 /s)

QO

77

111

120

 a o

35

23

22

44

42

18

6.9

46

33

28

34

28

46

36

54

36

48

57

27

22

19

16

Number 

of 

no-flow 

days

134

124

9

48

95

66

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Maximum

Flow 

(m 3 /s)

164

215

214

190

28

496

132

143

182

89

643

156

419

116

218

201

79

75

79

47

ODESSA

discharge Mean Number

Date annual of 

discharge no-flow 

(m3 /s) days

03/21/37 -

02/28/38 37

03/18/39 38

03/03/40 12 186

04/03/41 2.3 156

05/10/42 43 30

04/11/43 27 35

04/25/44 26 9

06/10/45 32 1

03/17/46 25 3

06/24/47 51 0

06/24/48 37 0

06/25/49 53 0

05/30/50 36 0

06/26/51 46 0

03/27/52 51 0

03/06/53 25 48

11/07/53 20 45

03/22/55 18 34

03/16/56 13 83

Maximum

Flow 

(m 3 /s)

215

O c/1

153

283

275

227

53

433

140

154

182

118

575

450

399

122

200

221

84

98

127

53

GRAND

discharge

Date

03/07/37

03/02/38

03/19/39

03/05/40

02/06/41

05/06/42

07/05/43

05/13/44

06/11/45

03/17/46

06/23/47

03/19/48

06/26/49

05/09/50

05/19/51

03/27/52

03/06/53

02/22/54

03/10/55

03/01/56

ISLAND

Mean 

annual 

discharge 

(m3 /s)

32

 ao

23

14

35

36

12

4.5

44

29

30

32

26

49

34

54

33

46

53

27

20

16

12

Number 

of 

no-flow 

days

145

135

215

64

81

169

158

121

51

30

0

10

0

4

0

0

0

0

92

100

103

130

47
TABLE 5. Historical discharge data Continued

OVERT0N

Year

1957

1958

1959

1960

1961

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

1973

1974

1975

1976

Maximum

Flow 

(mVs)

213

164

84

197

99

201

86

67

413

97

173

72

206

245

445

135

541

249

156

discharge

Date

05/25/57

05/26/58

03/29/59

03/24/60

06/19/61

06/09/62

02/15/63

04/07/64

06/26/65

03/02/66

07/08/67

02/22/68

06/30/69

06/26/70

06/13/71

05/14/72

05/15/73

03/21/74

06/21/75

Mean 

annual 

discharge 

(mVs)

23

37

25

30

24

38

28

24

35

41

34

31

38

49

89

53

109

94

33

32

Number 

of

no-flow 

days

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Maximum

Flow 

(m3 /s)

201

152

100

227

165

262

93

61

394

138

396

79

202

230

385

117

524

254

137

ODESSA

discharge

Date

05/26/57

05/28/58

07/04/59

03/24/60

05/22/61

06/09/62

02/15/63

04/07/64

06/26/65

10/19/65

06/14/67

02/24/68

07/01/69

06/26/70

06/13/71

05/16/72

05/31/73

03/22/74

06/23/75

Mean 

annual 

discharge 

(mVs)

20

36.

24

31

22

37

26

21

34

41

35

26

37

49

84

49

105

89

28 

26

Number 

of 

no-flow 

days

49

0

0

0

0

0

3

0

0

0

0

0

0

0

0

0

0

0

0 

0

Maximum

Flow 

(mVs)

165

133

113

286

154

198

96

96

348

140

510

108

210

196

334

135

504

220

163

GRAND ISLAND

discharge

Date

05/27/57

04/03/58

03/26/59

03/27/60

05/23/61

06/11/62

02/18/63

04/26/64

06/29/65

10/01/65

06/14/67

06/25/68

03/20/69

06/28/70

06/14/71

05/06/72

06/01/73

04/14/74

06/23/75

Mean 

annual 

discharge 

(m3 /s)

20

38

25

33

23

39

27

20

36

40

40

29

39

48

76

46

105

92

31

9ft £O

Number 

of 

no-flow 

days

65

0

43

52

15

0

46

14

0

20

0

0

0

0

0

0

0

11

0 

27

48

*g.S. Government Printing Office: 1978-777-102/2