U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2015–5127

Prepared in cooperation with the U.S. Army Corps of Engineers, Omaha District

Characteristics of Sediment Transport at Selected Sites 

Along the Missouri River, 2011–12
Cover photograph. Sampling the Missouri River near Omaha, Nebraska, on July 8, 2011. Note flooding in the background. Photograph 

by David Rus, U.S. Geological Survey.
Characteristics of Sediment Transport at 

Selected Sites Along the Missouri River, 

2011–12

By David L. Rus, Joel M. Galloway, and Jason S. Alexander

Prepared in cooperation with the 

U.S. Army Corps of Engineers, Omaha District

Scientific Investigations Report 2015–5127

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2015

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Suggested citation:

Rus, D.L., Galloway, J.M., and Alexander, J.S., 2015, Characteristics of sediment transport at selected sites along 

the Missouri River, 2011–12: U.S. Geological Survey Scientific Investigations Report 2015–5127, 34 p., http://dx.doi.

org/10.3133/sir20155127.

ISSN 2328-0328 (online)
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Purpose and Scope ..............................................................................................................................2

Description of Study Area ...................................................................................................................2

Hydrologic Characteristics ........................................................................................................2

Sediment Budget Characteristics.............................................................................................4

Methods...........................................................................................................................................................5

Sediment-Data Collection and Laboratory Analyses......................................................................6

Streamflow Data Collection ................................................................................................................7

Total-Sediment Load.............................................................................................................................7

Measured Sediment Load ..........................................................................................................7

Estimated Sediment Load...........................................................................................................8

Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 

2011–2012...........................................................................................................................................8

Sediment-Load Sampling Results ......................................................................................................9

Sediment Depletion ..............................................................................................................................9

Bar Formation and Erosion in the Gavins Point Segment ..............................................................9

Contribution of Bedload to Total Load ...............................................................................................9

Changes in Transport Mechanisms Between the Gavins Point and 

Channelized Segments.........................................................................................................16

Sediment Load Estimates ..................................................................................................................16

Summary........................................................................................................................................................21

References Cited..........................................................................................................................................22

Appendix Tables...........................................................................................................................................25
iv

Figures

1. Map showing the Missouri River Basin with locations of sediment-data

collection sites ..............................................................................................................................3

2. Graphs showing time series of total-sediment load and daily mean streamflow of

Missouri River, selected sites, 2011.........................................................................................14

3. Graphs showing time series of total-sediment load and daily mean streamflow of

Missouri River, selected sites, 2012.........................................................................................15

4. Graphs showing relations of sediment loads estimated by the Modified-Einstein

Procedure to measured loads for total-sediment load; and bedload, for selected

Missouri River sites, 2011–12....................................................................................................20

Tables

1. Streamflow and sediment data-collection sites for the Missouri River and

selected tributary streams ..........................................................................................................2

2. Summary of streamflow characteristics for two Missouri River sites................................4

3. Terms used to describe sediment-transport characteristics................................................5

4. Measured sediment loads for six Missouri River sites on dates of sample

collection, 2011–12 .....................................................................................................................10

5. Sediment loads estimated by the Modified-Einstein Procedure for six Missouri

River sites, 2011–12 ....................................................................................................................17

Appendix Tables

1–1. Suspended-sediment concentrations and grain sizes for six Missouri River sites,

2011–12 .........................................................................................................................................26

1–2. Grain sizes and mass of bedload samples for six Missouri River sites, 2011–12 ............29

1–3. Grain sizes of bed-material samples for six Missouri River sites, 2011–12 ......................32
v

Conversion Factors

Inch/Pound to International System of Units

Multiply By To obtain

Length

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Flow rate

foot per second (ft/s) 0.3048 meter per second (m/s)

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

Mass

ounce, avoirdupois (oz) 28.35 gram (g) 

ton per day (ton/d) 0.9072 metric ton per day

ton per day (ton/d) 0.9072 megagram per day (Mg/d)

Datum

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Supplemental Information

Concentrations of suspended sediment in water are given in milligrams per liter (mg/L).

Characteristics of Sediment Transport at Selected Sites 

Along the Missouri River, 2011–12

By David L. Rus, Joel M. Galloway, and Jason S. Alexander

Abstract

Extreme flooding in the Missouri River in 2011, followed by a year of more typical streamflows in 2012, allowed 

the sediment-transport regime to be compared between the 

unprecedented conditions of 2011 and the year immediately 

following the flooding. As part of a cooperative effort between 

the U.S. Geological Survey and the U.S. Army Corps of Engineers, this report follows up U.S. Geological Survey Scientific 

Investigations Report 2013–5006 by comparing sediment 

transport between years and among sampling sites spanning 

the Garrison Segment in North Dakota, the Gavins Point Segment downstream from Lewis and Clark Lake, and a part of 

the Channelized Segment along the Nebraska-Iowa border. 

Suspended sediment, bed material, bedload, and streamflow 

data from June 2011 through November 2012 were designated as “measured” total loads, wash loads, and bed-material 

loads; and, alternatively, were applied to the Modified-Einstein 

Procedure to compute sediment loads that were designated as 

“estimated” total loads.

Beyond the expected result that sediment loads were 

much lower during typical streamflows than those measured 

during the flooding, the measured data indicated some localized sediment-transport processes for further examination. 

Extreme and prolonged flooding can temporarily deplete sediment supplies locally, and evidence indicating such depletion 

was present at some sites. Unexpectedly high bed-material 

loads in the Gavins Point Segment may reflect episodic bar 

erosion just upstream from the sampling site. The relative 

contribution of bedload was typically 10 percent or less of 

the total load during the flooding. Following the flooding, this 

relative amount increased at some sites but not others, the 

reasons for which are possibly related to differences in stream 

velocity. Ultimately, the bedload decreased as it entered the 

Channelized Segment because of increased velocity and the 

turbulent mixing ability of the river as compared to the Gavins 

Point Segment. This turbulent mixing may also convert bedmaterial load into wash load, thereby rendering those sediments unavailable for creating sandbars and other bedforms. 

Though some of the sampling data support this premise, it 

was not consistently manifested by differences between the 

sediment load of the two segments during typical-streamflow 

conditions.

The Modified-Einstein Procedure tended to predict 

greater total-sediment loads when compared to measured values. These differences may be the result of sediment deficits 

in the Missouri River that lead to an overprediction by the 

Modified-Einstein Procedure, the unsampled zone above the 

streambed that leads to an underprediction by the suspended 

sampler, or general uncertainty in the sampling approach. The 

differences between total-sediment load obtained through 

measurements and that estimated from applied theoretical 

procedures such as the Modified-Einstein Procedure pose a 

challenge for reliably characterizing total-sediment transport. 

Though it is not clear which of the two techniques is more 

accurate, the general tendency of the two to be within an order 

of magnitude of one another may be adequate for many sediment studies.

Introduction

In 2011, a combination of above-normal snowpack in 

headwater regions of Montana and Wyoming, near record 

snowfall and saturated soil conditions in North and South 

Dakota, and record rainfall in May across the upper Missouri 

River Basin contributed to record annual runoff into the Missouri River Mainstem Reservoir System (Grigg and others, 

2012; Vining and others, 2013). These unprecedented inflows 

led to releases of record high-magnitude discharges from the 

main-stem reservoirs operated by the U.S. Army Corps of 

Engineers (USACE) into the Missouri River (Holmes and others, 2013). These record discharges eroded, transported, and 

deposited massive amounts of sediment, which, at some locations, dramatically altered the channel and flood plain geomorphology (Alexander and others, 2013; Juracek, 2014; Schenk 

and others, 2014). Measured Missouri River discharges in 

2012 contrasted markedly with its 2011 peaks, with most sites 

characterized by below-average peak discharges.

Although the large discharges in 2011 provided an opportunity to examine characteristics of total-sediment transport in 

the Missouri River at high-magnitude discharges and over a 

long duration (Galloway and others, 2013), discharges in 2012 

provided an opportunity to compare total-sediment-transport 

characteristics during more typical discharge conditions and 

to re-examine methods of sediment-transport estimation. 
2 Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12

To characterize total-sediment transport on the Missouri River 

during 2011 and 2012, the U.S. Geological Survey (USGS), in 

cooperation with the USACE, collected sediment samples at 

selected locations extending from Washburn, North Dakota, to 

Nebraska City, Nebraska (fig. 1).

Purpose and Scope

This report supplements USGS Scientific Investigations Report 2013–5006, which described a previous study of 

sediment transport at selected sites along the Missouri River 

during the high-streamflow conditions of 2011 (Galloway and 

others, 2013). The focus herein is sediment transport during 

the more typical-streamflow conditions of 2012, in contrast 

to those of 2011. Four of the original six study sites on the 

Missouri River sampled in 2011 (at Washburn, N. Dak.; at 

Bismarck, N. Dak.; near Maskell, Nebr.; at Sioux City, Iowa; 

at Omaha, Nebr.; and at Nebraska City, Nebr.) were resampled 

in 2012 for suspended sediment, bedload, and bed material 

(fig. 1). These results were used to provide further information 

on the characteristics of Missouri River sediment, including suspended-sediment concentration (SSC) and grain-size 

distribution, bedload mass and grain-size distribution, suspended and bedload transport rates, and temporal and spatial 

variability therein. Though much more suspended-sediment 

data are available for some sites as a result of historical and 

ongoing monitoring, this report focuses on datasets that allow 

the total-sediment transport to be characterized on a given date 

through the inclusion of suspended-sediment, bedload, and 

bed-material data.

Description of Study Area

Six locations (sites) were sampled to characterize 

total-sediment transport in the Missouri River in 2011. The 

Washburn and Bismarck sites were located between Lake 

Sakakawea and Lake Oahe (henceforth referred to as the “Garrison Segment”); the Maskell site was located downstream 

from Lewis and Clark Lake in a free-flowing, nonchannelized 

length of the river (referred to as the “Gavins Point Segment”); and the Sioux City, Omaha, and Nebraska City sites 

were located within part of the channelized section of the river 

(referred to as the “Channelized Segment”) (table 1, fig. 1). 

The Washburn and Bismarck sites (Garrison Segment), the 

Maskell site (Gavins Point Segment), and the Sioux City site 

(Channelized Segment) were resampled in 2012 for totalsediment transport. Streamflow data from two additional 

tributary sites (table 1) were used in estimating streamflow at 

the Maskell site (a stage-only streamgage).

In the remainder of this section of the report, a basic 

description of the hydrologic and sediment budget characteristics of the sampling sites is provided. More comprehensive 

information is in Galloway and others (2013). Some of the 

segment characteristics are described in terms of the USACE 

system of river miles, which reference the mileage upstream 

from the confluence with the Mississippi River along the Missouri River channel centerline as it existed in 1960 (Dan Pridal, U.S. Army Corps of Engineers, written commun., 2012).

Hydrologic Characteristics

Streamflow at all six sites is affected by upstream reservoirs (Fort Peck Lake, Lake Sakakawea, Lake Oahe, Lake 

Sharpe, Lake Francis Case, and Lewis and Clark Lake) that 

dampen hydrologic extremes in the Missouri River (National 

Research Council, 2002). Continuous-streamflow records are 

available for four of the six sites from the USGS, two of which 

are summarized in table 2 (U.S. Geological Survey, 2015). At 

both sites, streamflow conditions during 2011 were the highest 

since the 1966 completion of the reservoir system. Although 

the reservoirs attenuated the peak streamflows in 2011 by 

as much as 100,000 cubic feet per second (ft3/s) (U.S. Army 

Corps of Engineers, 2012), they nonetheless released streamflows at or above flood levels and lengthened the duration of 

those high streamflows. In 2011, the daily mean streamflows at 

the Bismarck site were greater than 68,900 ft3/s—the existing 

peak-of-record after dam completion but prior to 2011—for 

Table 1. Streamflow and sediment data-collection sites for the Missouri River and selected tributary streams.

[NA, not applicable]

Site name 

(fig. 1)

Main-stem 

segment

U.S. Geological Survey 

station number Full station name Data collected during 2011–12

Washburn Garrison 06341000 Missouri River at Washburn, North Dakota Sediment.

Bismarck Garrison 06342500 Missouri River at Bismarck, North Dakota Streamflow, sediment.

Maskell Gavins Point 06478526 Missouri River near Maskell, Nebraska Sediment.

Akron NA 06485500 Big Sioux River at Akron, Iowa Streamflow.

Vermillion NA 06479010 Vermillion River near Vermillion, South Dakota Streamflow.

Sioux City Channelized 06486000 Missouri River at Sioux City, Iowa Streamflow, sediment.

Omaha Channelized 06610000 Missouri River at Omaha, Nebraska Streamflow, sediment.1

Nebraska City Channelized 06807000 Missouri River at Nebraska City, Nebraska Streamflow, sediment.1

1

Bedload samples collected in 2011 only.
rol14-EMNR00-0066 Rus Figure 1

NORTH DAKOTA

NEBRASKA

WYOMING

COLORADO

MINNESOTA

IOWA

KANSAS

IDAHO

MANITOBA

SASKATCHEWAN

UTAH

Omaha

Denver

Pierre

Cheyenne

Billings

Williston

SiouxFalls

Great Falls

ARIZONA NEW MEXICO OKLAHOMA

ALBERTA

ONTARIO

Bismarck

MONTANA SOUTH DAKOTA

KansasCity

Jefferson City

Yankton

Helena Washburn

Nebraska

City

Maskell Sioux City

Vermillion

Akron

110° 100° 

45°40°

Base from U.S. Geological Survey digital data, 2013, 1:10,000,000Albers Equal-Area Conic projectionStandard parallels 29°30’N and 45°30’N, central meridian 96°00’W

North American Datum of 1983

0 50 100 200 MILES

0 50 100 200 KILOMETERS

Milk River

Yellowstone

River

North Platte

River

South

Platte River

Platte River

Ka nsas River

LakeOahe

Lake 

Sakakawea

Ft. Peck

Lake

Lewis and Clark Lake

Lake Sharp

Lake FrancisCase

JamesRiver Mississippi

Heart Ri ver

Knife River

Little Sioux River

Big Sioux River

Ve

rmillion River

EXPLANATION

Data collection siteMissouri River Basin boundary

SedimentStreamflow and sedimentStreamflowGarrisonGavins PointChannelized

MissouriRiver

Missouri

River

River segment

PONCA 

STATE PARK

Figure 1. Missouri River Basin with locations of sediment-data collection sites.
4 Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12

98 consecutive days. Similarly, at the Sioux City site, daily 

mean streamflows in 2011 were greater than 104,000 ft3/s for 

90 consecutive days. In contrast, streamflow conditions in 

2012 more closely approximated the long-term average from 

1966 to 2010.

Sediment Budget Characteristics

The sediment budgets of altered rivers such as the Missouri River are important in characterizing their geomorphic 

condition and potential for future change (Jacobson and 

others, 2009). Sediment budgets account for the erosion, 

transport, and deposition of sediments within a river as well as 

the dynamic interactions between those processes and streamflow. If a river has less capacity to transport sediment than the 

sediment quantity that is being supplied (a common scenario 

where a river enters a reservoir), the river is said to have a 

sediment surplus, and those sediments will eventually deposit 

into the streambed and increase the amount of sediment in 

storage. Conversely, if a river has a greater capacity to transport sediment than the sediment quantity that is being supplied (a common scenario downstream from dams; Williams 

and Wolman, 1984), then the river has a sediment deficit and 

consequent erosional processes will remobilize the sediments 

out of storage (in the streambed or stream banks) to meet that 

excess transport capacity.

In historical context, the completion of upstream reservoirs has reduced the downstream sediment supply at all six 

sites (National Research Council, 2002; Jacobson and others, 

2009; National Research Council, 2011). In addition, the systematic bank stabilization and channelization downstream from 

Ponca State Park, river mile (RM) 753 (fig. 1), has reduced the 

supply of bank-eroded sediment to downstream sites (Sioux 

City, Omaha, and Nebraska City sites). With the exception 

of the Nebraska City site, the channelization and dams have 

resulted in channel incision, with the greatest amounts of incision measured at sites nearest to dam outlets (Williams and 

Wolman, 1984; Chen and others, 1999; Jacobson and others, 

2009). Upstream from the Nebraska City site, sediment contributions from the Platte River may largely have offset incision from that confluence downstream. Channel incision and 

bank-erosion rates in the Garrison Segment (the Washburn and 

Bismarck sites) were much greater during the initial 20 years 

following completion of Lake Sakakawea (fig. 1) as compared 

to more recent periods (Pokrefke and others, 1998), indicating 

that the segment may be recovering its dynamic equilibrium 

(Biedenharn and others, 2001; Skalak and others, 2013). A 

similar trend of diminishing incision and erosion was not as 

apparent at the Maskell site (Pokrefke and others, 1998) subsequent to the completion of Lewis and Clark Lake, indicating 

that erosional processes may be ongoing at this site.

More recently, the extreme and prolonged flooding of 

2011 affected the sediment budget in the Missouri River. The 

high streamflows added a considerable amount of energy for 

mobilizing sediment stored in the channel while the reservoirs 

simultaneously trapped sediment and limited the sediment 

supply available to downstream segments. Potentially, such a 

situation might cause a sediment-supply deficit in the part of 

the river system downstream from the impoundments, dependent on the magnitude of sediment discharges from tributaries. 

The flood of 2011 was unique in that most of the streamflow 

originated in the part of the basin regulated by the reservoir 

system. Unlike prior floods, the tributaries downstream from 

the reservoirs were not contributing substantial amounts of 

sediment to the main stem to offset that deficit, which may 

explain the relatively low suspended-sediment concentrations 

in 2011 (Alexander and others, 2013). It also implies that 

much of the flood-mobilized sediment had to originate from 

within the local main-stem river segment through streambed, streambank, and, where applicable, flood-plain erosion, 

thereby depleting the local sediment in storage.

Horowitz (2003) pointed out that it took about 3 years 

for the local sediment in storage to recover following the 

1993 floods on the Mississippi River. Typical of many fluvial 

systems, erosion of sediments in one location generally led to 

the deposition of those sediments elsewhere. At several levee 

breaks, sediments were transported out of the stream channel 

and onto the flood plain, where they subsequently were deposited as crevasse splay deposits (Alexander and others, 2013). 

At other locations, sandbars were formed (such as one observed 

just upstream from the Maskell site) and numerous side-channel 

chutes were cut off from the main channel of the river as a result 

of sand deposition. Similar to the Mississippi River following 

the 1993 floods (Horowitz, 2003), it is likely that the channel 

of the Missouri River will recover some of its balance of local 

sediment storage through erosional processes that may continue 

for several years after 2011, and may include the erosion of 

morphometric features that were created by the 2011 flood.

Table 2. Summary of streamflow characteristics for two Missouri River sites.

[All streamflows are reported in cubic feet per second]

Summary period, 

in water years

Bismarck, North Dakota, site Sioux City, Iowa, site

Mean annual 

streamflow Peak streamflow Mean annual streamflow Peak streamflow

1966–2010 22,800 68,900 30,700 104,000

2011 53,200 155,000 79,100 192,000

2012 25,000 30,400 34,400 45,100
Methods 5

Methods

The following sections describe methods used for the 

assessment of sediment transport during 2011 and 2012. 

Generally, sediment transport was estimated using data for 

streamflow, SSC, bedload, and bed-material samples analyzed 

for grain-size distribution. These data were collected by the 

USGS at six study sites on the main stem of the Missouri 

River (table 1; fig. 1).

This report uses terminology for sediment transport 

that categorizes sediment load either according to a measurement principle or a transport mechanism (Church, 

2006). Terms used to describe sediment characteristics by 

the measurement principle include suspended-sediment 

load, bedload, and bed material (table 3). Terms used to 

describe sediment characteristics by the transport mechanism include wash load, bed-material load, and total-sediment load (table 3).

Measurements and sample collection were generally 

consistent in methodology from site to site and from high to 

typical streamflow with a few exceptions. Most measurements 

were made from bridges rather than from boats. The collection 

of bedload samples from a boat during the high-streamflow 

conditions was deemed both dangerous and prone to sampling 

error caused by boat movement. The suspended-sediment 

samples and streamflow measurements at the Sioux City, 

Omaha, and Nebraska City sites were collected from a boat as 

part of another data-collection program done simultaneously 

with this study.

Suspended-sediment and bedload sampling took place 

on the same day, with one exception (the Nebraska City site 

samples of June 27 and 28, 2011). With the exception of the 

Omaha site, all field measurements and samples for each study 

site were collected within the same reach of the Missouri 

River. For these purposes, a river reach can be considered a 

length of river approximately 10 channel widths long. At the 

Omaha site, measurements of SSC were made from a boat 

near U.S. Interstate 480 (I–480) at RM 616. Because of safety 

concerns associated with heavy traffic on the I–480 Bridge, 

measurements of bedload and bed material were made about 

10.4 miles upstream at the U.S. Interstate 680 (I–680) Bridge 

at RM 626.4, which was closed to traffic during the 2011 

sampling period. Unfortunately, hydraulic conditions were 

quite different at the two measurement locations in 2011. At 

the I–680 Bridge, the river flooded most of the valley bottom 

and attained a width of more than 4 miles during the peak of 

the flood, but measurements of bedload were limited to the 

main channel under the bridge, which contained most, but not 

all, of the streamflow. In comparison, all of the streamflow 

near the I–480 Bridge was confined to the main channel by 

levees and was approximately 0.2 miles wide. Although most 

of the streamflow at the I–680 Bridge was located within the 

0.2-mile-wide channel under the bridge, there were likely 

higher stream velocities and thus greater sediment-transport 

capacity at the I–480 Bridge. Consequently, some sediment 

grains that were transported as bedload at the I–680 Bridge 

may have become suspended load once reaching the area near 

the I–480 Bridge. Therefore, total-sediment transport estimates 

for the Omaha site may be positively biased as a result of the 

double-accounting of these grains.

Table 3. Terms used to describe sediment-transport characteristics.

[Descriptions used in this table were derived from Church, 2006 and Edwards and Glysson, 1999]

Term Description

Measurement principle

Suspended-sediment load Component of sediment load consisting of inorganic grains that move in a downstream direction by suspension 

within the water column; operationally, it is the component of sediment transport within the vertical interval 

from the water surface down to a depth associated with the unsampled zone of the water sampler.

Bedload Component of sediment load consisting of inorganic grains that move in a downstream direction by rolling, 

saltating, or bouncing along the riverbed or, operationally, the component of sediment in transport within the 

vertical interval from the surface of the riverbed up to the height of the top of the bedload sampler nozzle.

Bed material Sediment grains on the surface of the bed of the river and below the surface down to the maximum sampling 

depth of the sampling device (varies with sampler type and design).

Transport mechanism

Wash load Component of sediment load that remains continuously in suspension under given hydraulic conditions. Wash 

load consists of grain sizes finer than those represented in the bed, and therefore constrained to being measured in the suspended-sediment sample.

Bed-material load Component of sediment load (whether measured as bedload or in suspension) able to be moved under given 

hydraulic conditions but unable to remain in suspension continuously. Bed-material load consists of grain 

sizes represented in the streambed.

Total-sediment load Computed as either (1) sum of the wash load and the bed-material load or (2) the sum of the bedload and 

suspended-sediment load.
6 Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12

Sediment-Data Collection and Laboratory 

Analyses

Suspended-sediment, bedload, and bed-material samples 

were collected at various time intervals from all six Missouri River sites in 2011 and from the Washburn, Bismarck, 

Maskell, and Sioux City sites in 2012 (fig. 1). Because of 

practicality considerations, samples were collected from the 

main channel of the river only and did not include the sediment load associated with flood-plain overbank streamflow; 

however, flood-plain overbank streamflow only coincided with 

sampling at the Omaha and Nebraska City sites and only during the highest-streamflow conditions at those sites. Though 

field techniques did not vary with streamflow condition, the 

samples were categorized as being high-streamflow samples or 

typical-streamflow samples based on the measured streamflow 

at the time of sampling. Most of the samples collected in 2011 

were associated with high streamflow, and all of the samples 

collected in 2012 were associated with typical-streamflow 

conditions.

Suspended-sediment samples were collected to estimate 

the suspended load transported past the six sites. Samples were 

collected isokinetically (water enters the sampler nozzle at the 

same velocity as the stream current) using depth-integrated 

samplers (Davis, 2005) at multiple locations along a transect 

(or cross-section) to represent the vertical and horizontal variability of suspended sediment in the stream channel. 

Different types of suspended samplers and sampling 

methods were used at different sites because some of the samples were collected as part of a previously established datacollection program. Suspended samples from the three most 

upstream sites—Washburn, Bismarck, and Maskell—were 

collected using a US-D-96 bag sampler (Davis, 2005). These 

suspended samples were collected at 10 stations across the 

channel, spaced at equal intervals using the equal-width increment (EWI) sampling method (Edwards and Glysson, 1999). 

Samples collected using the EWI method were composited in 

a plastic churn splitter for subsequent processing into aliquots 

using plastic bottles.

Suspended samples from the three most downstream 

sites—Sioux City, Omaha, and Nebraska City—were collected using one of two samplers. Samples collected before 

July 20, 2011, used a US P–61 sampler (Davis, 2005), which 

normally is used for collecting a sample at a discrete point 

but can be used in depth-integrated sampling if the nozzle is 

left in the open position throughout the sample (Edwards and 

Glysson, 1999). Samples collected after July 20, 2011, used a 

US-D-96 bag sampler (Davis, 2005). The suspended samples 

from the three downstream sites were collected at three stations along the transect, specified using the equal-discharge 

increment (EDI) method (Edwards and Glysson, 1999). For 

samples collected using the EDI method, samples associated with the individual stations (verticals) were submitted 

separately for laboratory analysis, at which time they were 

composited.

In many cases at all of the sites, the sampler was not 

lowered all the way to the streambed to avoid the potential for 

compromising the sample by inclusion of bed material. Therefore, the suspended-sediment sample did not include the water 

column interval from 0.5 to 2 feet (ft) above the streambed.

Replicate samples were obtained for SSC determinations 

by collecting a second representative volume of water from 

the churn splitter concurrently with the regular sample. Nine 

such replicate samples were collected: four for the Washburn 

site, three for the Bismarck site, and two for the Maskell site. 

The relative standard deviation (Mueller and others, 2015) of 

the pairs of replicate SSC samples varied between 2 and 41 

percent and averaged 14 percent. Some of the variability is the 

result of the high concentration of sand-sized grains in suspension in the samples. For example, the replicate pair with the 

largest variability included a sample in which 97 percent of the 

sediments were sand-sized or coarser. Though better reproducibility would have been desirable, the results were considered 

acceptable given the flood conditions.

Bedload samples were collected to estimate the sediment 

transport near the streambed at the six sites. Bedload samples 

were obtained using a Helley-Smith Model 8035 sampler (at 

the Washburn and Bismarck sites) or a BL–84 sampler (at the 

Maskell, Sioux City, Omaha, and Nebraska City sites) (Davis, 

2005) suspended on a cable from a crane. Both samplers are 

designed for orientation in the direction of streamflow when 

deployed on the streambed. Bedload samples were collected 

at 20 equally spaced verticals across the stream transect. At 

the Washburn and Bismarck sites, sediment masses from 

each vertical were composited before further processing. At 

the Maskell, Sioux City, Omaha, and Nebraska City sites, 

the 20 equally spaced verticals were sampled twice, using 

2 sequential passes across the bridge for every sample. The 

bedload was derived by compositing the sediments from all 

verticals before being weighed. The composited sediments 

were then subsampled for sieve analysis.

Due to time and resource limitations, replicate bedload 

samples were not able to be collected; however, for a subset 

of 29 bedload samples (associated with the 2011 Maskell, 

Sioux City, Omaha, and Nebraska City samples), sediments 

from each vertical were air dried and weighed separately at the 

USGS Nebraska Water Science Center prior to being composited. Relative standard deviations between passes averaged 19 percent but were as high as 50 percent in one sample. 

Because these weights were not obtained using standard procedures, the true variability between passes is not confidently 

known. In addition, the standard procedure of compositing 

two sequential passes is intended to reduce the effect of this 

variability on the final bedload values used in the analyses.

The hydraulic conditions of the Missouri River in 2011 

likely exceeded the operational range of the Helley-Smith and 

BL–84 bedload samplers. Criteria for the proper collection 

of bedload at any given vertical include (1) that the sampler 

comes to rest on the streambed with no forward velocity, 

(2) that the sampler remains stationary during collection, and 

(3) that, in lifting the sampler off the streambed, it does not 
Methods 7

maintain contact with the streambed (such as might happen 

on the leeward—or downstream facing—side of a dune). 

Violation of these conditions may lead to the dredging of bed 

material that was not concurrently part of the bedload. The 

hydraulic conditions of the Missouri River in 2011 challenged 

these criteria with depths exceeding 50 ft (at sites in the lower 

segment) and stream velocities frequently exceeding 10 feet 

per second (ft/s). Before collecting the first sample, the collection procedures were refined to gain as much confidence 

as possible that the criteria were being met. This included 

the addition of as much as 75 pounds of weight to the sampler (using sounding weights affixed above the sampler), the 

lowering of the sampler as quickly as the equipment would 

allow (typically at a downward rate of 4 to 5 ft/s), the maintenance of slack cable during the sampling period (to the extent 

possible given the hydraulic conditions), and the retrieval of 

the sampler as quickly as the equipment would allow (typically at an upward rate of 3 to 5 ft/s). Without any means of 

visually observing the behavior of the sampler on the bed of 

the river, this technique was assumed to be effectively attaining the criteria. In addition, the temporal variation in bedload 

at a given vertical will increase as the sampling time on the 

streambed becomes small relative to the cycle period of the 

dune being measured (Edwards and Glysson, 1999). Because 

of the limited sampler volume, the samplers were left on the 

streambed for 20 to 40 seconds at individual stations during 

2011 sampling; in 2012, the samplers were left on the streambed for 60 to 120 seconds.

Bed-material samples were collected using a US BM–54 

sampler (Davis, 2005). The bed-material samples were collected at five equally spaced stations (hereinafter referred to 

as “verticals”) along the stream transect and composited for 

analysis. Four planned bed-material samples (two each from 

the Omaha and Nebraska City sites) were not collected as a 

result of sampler malfunctions.

All suspended-sediment samples were analyzed for concentration and grain-size distribution at the USGS Sediment 

Laboratory at Iowa City, Iowa, using methods described in 

Guy (1969). Bedload samples were weighed and bed-material 

and bedload samples were analyzed for grain-size distribution 

at the same laboratory using the methods described in Guy 

(1969). Results from the laboratory analyses were stored in the 

USGS National Water Information System (NWIS) database 

(U.S. Geological Survey, 2015).

Streamflow Data Collection

Streamflow data were important for understanding the 

hydraulic conditions of the river and the resulting capacity to transport sediment. Streamflow measurements were 

made concurrently with most of the sediment samples collected at the six sites. Streamflow was measured using an 

acoustic Doppler current profiler (ADCP) with the methods 

and procedures described in Mueller and Wagner (2009). For 

analyzing sediment transport, the streamflow measurements 

at the Nebraska City site that included flooded-overbank areas 

were adjusted such that the adjusted streamflow corresponded 

only to the area where sediment-transport measurements 

were being made. For example, on June 27, 2011, streamflow 

in the main channel at the Nebraska City site was estimated 

at 193,000 ft3/s, or 91 percent of the total streamflow of 

211,000 ft3/s (U.S. Geological Survey, 2015).

In addition to the discrete measurements, continuousstreamflow data were available at the Bismarck, Sioux City, 

Omaha, and Nebraska City sites (table 1, fig. 1). Streamflow 

data from the Bismarck site were used as estimated streamflow 

for the computation of sediment loads at the Washburn site. 

Daily mean streamflow for the Maskell site was estimated 

by subtracting the daily mean streamflow for the Big Sioux 

River (Big Sioux River at Akron, Iowa, USGS station number 

06485500, fig. 1, table 1) and the Vermillion River (Vermillion River near Vermillion, S. Dak., USGS station number 

06479010, fig. 1, table 1) from the daily mean streamflow at 

the Sioux City site—located 43 river miles downstream from 

Maskell—for the same date (U.S. Geological Survey, 2015).

Total-Sediment Load

One of the most difficult problems in open-channel 

hydraulics is the determination of the rate of movement of 

material along the streambed (bedload; table 3) (Einstein, 

1950; Gray and others, 2010); however, an estimate of totalsediment load could be underestimated if bedload is neglected. 

Total-sediment load was estimated at each site using two 

methods: the sum of sampled rates of transport of suspended 

sediment and bedload, and a computational estimate derived 

from the Modified-Einstein procedure of Colby and Hembree 

(1955).

Measured Sediment Load

The measured total-sediment load was computed as the 

sum of the measured suspended-sediment load and bedload. 

Suspended-sediment loads (sediment discharge) were estimated for the six sites using daily mean streamflow data and 

measured SSC data (Porterfield, 1972) collected at each site:

Qs = Qw Cs Ks (1)

where

Qs is the suspended-sediment load (sediment 

discharge), in tons (English short tons) per 

day;

Qw is the daily mean streamflow (water 

discharge), in cubic feet per second;

Cs is the SSC, in milligrams per liter; and 

Ks is a coefficient (0.0027) to convert the units of 

measurement of streamflow and SSC into 

tons per day and assumes a specific gravity 

of sediment of 2.65.
8 Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12

The bedload component was calculated from the measured data using the following equation (Edwards and Glysson, 1999):

Qb = Kb(WT/tT)MT (2)

where

Qb is the bedload, in tons per day;

Kb is a units conversion factor (10.8 for a 3-inch 

wide nozzle);

WT is the total width of the stream from which 

samples were collected, in feet, and is 

equal to the increment width times the total 

number of verticals sampled;

t

T is the total time the sampler was on the 

streambed, in seconds, computed by 

multiplying the individual sample time 

by the total number of verticals sampled; 

and

MT is the total mass of sample collected from 

all verticals sampled in the transect, in 

ounces.

Estimated Sediment Load

The second method to estimate sediment transport used 

a theoretical model to quantify bedload. Einstein (1950) first 

presented the technique for calculating the transport of sediment with grain sizes also present in appreciable quantities in 

the streambed or the bed-material load. This method used a 

probabilistic relation of SSC with stream velocity over a given 

vertical profile and for a finite longitudinal distance along a 

given river reach. Colby and Hembree (1955) and Colby and 

Hubbell (1967) developed a modified version of Einstein’s 

procedure (Modified-Einstein Procedure [MEP]) that used sediment and hydraulic data from a single transect to calculate the 

total bed-material load for a specific stream reach. The MEP 

is considered an improvement on the original Einstein method 

because it is simpler in computation and it uses characteristics 

more readily available from typical measurements of sediment 

conditions at a site. The MEP model was implemented for this 

study by using the executable program Bureau of Reclamation Automated Modified-Einstein Procedure (BORAMEP) 

(Holmquist-Johnson and others, 2009). Input data needed for 

the MEP model include streamflow, average channel velocity, 

wetted channel width, average channel depth, water-surface 

slope, water temperature, SSC, the grain-size distributions 

of the suspended sediment and bed material, and the proportion of the suspended sediment also represented in the bed. A 

water-surface slope of 0.00017 ft of vertical change for every 

foot traveled downstream was assumed from the slope of the 

streambed given in Carlston (1969). Though this assumption 

may not have been explicitly met, sensitivity analysis indicated that slope did not affect results even when varied over 

three orders of magnitude relative to the assumed streambed 

slope.

Although MEP estimates are commonly referred to as 

“total-sediment discharge” procedures (Einstein, 1950; Colby 

and Hembree, 1955), it is important to note that the predictive 

capacity of the MEP is limited to estimates of the bed-material 

load or the transport of grain sizes represented in the streambed. The transport of wash load (table 3) is derived from 

erosional processes external to the hydraulics of the local river 

reach such as rainfall-derived runoff, tributary inputs, and 

bank erosion. Therefore, it is a supply-dependent component 

of sediment transport, and must be incorporated separately. 

However, the measurements of suspended-sediment load 

include the wash load and the suspended part of the bed-material load.

For this report, the wash load was classified as that part 

of the suspended-sediment load consisting of grain sizes finer 

than those represented in the bed. More specifically, the fifthpercentile diameter of the bed-material grain-size distribution 

was used as the threshold for determining the percentage of 

the suspended-sediment load that was considered wash load. 

The remaining suspended-sediment load (consisting of grain 

sizes coarser than the threshold diameter) was considered 

bed-material load that was in suspension. Because the MEP 

method utilizes the suspended bed-material load to predict 

the total bed-material load, the wash load was removed from 

the suspended-sediment load before input to the BORAMEP 

program. The wash load was then added to the BORAMEPderived estimate of bed-material load to produce the MEPestimated total-sediment load (Colby and Hembree, 1955).

Characteristics of Sediment Transport 

at Selected Sites Along the Missouri 

River, 2011–2012

In much of the Missouri River, the 2011 streamflows 

were unprecedented since the advent of the main-stem dams 

era, and much has been written about the flood’s effect on 

sediment transport (Alexander and others, 2013; Galloway and 

others, 2013; Juracek, 2014; Schenk and others, 2014). This 

section of the report focuses on Missouri River sediment transport during the more typical-streamflow conditions of 2012 

and contrasts it with that during the high streamflows of 2011 

previously reported by Galloway and others (2013). Sedimenttransport characteristics are described below in terms of the 

transport mechanisms (wash load and bed-material load) and 

measurement principle (suspended-sediment load, bedload, 

and bed-material characteristics), either of which can be used 

to quantify total-sediment load (table 3).

Generally speaking, the great magnitude of the streamflows of 2011 obscured subtle differences in sediment-transport characteristics among the sites. These differences became 

more apparent during typical-streamflow conditions during 

2012. Those differences among sites also are examined in this 

section of the report.
Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–2012 9

Sediment-Load Sampling Results

A total of 46 samples associated with high-streamflow 

conditions and 40 samples associated with typical-streamflow 

conditions were analyzed from six sites between June 2011 

and November 2012. The field data included streamflow, 

suspended-sediment concentration and grain size, bedload and 

grain size, and bed-material grain size characteristics of the 

river (tables 1–1, 1–2, and 1–3). These data were used to compute the total-sediment load and to discriminate between wash 

load and bed-material load (table 4, fig. 2, fig. 3).

At all sites, sediment loads were considerably lower during typical conditions as compared to the high-streamflow conditions of 2011 (table 4). Given the extreme decrease in streamflow, this is not noteworthy; however, there are more subtle 

aspects to these decreases that warrant further examination.

Sediment Depletion

Because the high streamflow of 2011 was coupled with 

the sediment trapping effect from the reservoirs, the resulting 

conditions were unnatural with respect to sediment transport. 

Local sediments stored in the channel were probably mobilized and transported downstream. The extended duration of 

the flood made it more likely that these locally stored sediments may have become depleted, and consequently may take 

several years to be replenished (Horowitz, 2003). Decreased 

streambed elevations that persisted into 2013 at the Sioux City 

and Omaha sites (Juracek, 2014) provide some evidence of 

sediment depletion in the Channelized Segment. In the Garrison Segment, a 157-percent increase in the mean bed-material 

load from Washburn to Bismarck (table 4) in the absence of 

any major tributary inputs during the typical streamflows following the flooding indicates that erosional processes within 

the channel, such as bank and bar erosion and streambed incision, are contributing sediments to downstream reaches. This 

also may indicate that the Garrison Segment has shifted out of 

dynamic equilibrium following the 2011 flood.

Bar Formation and Erosion in the Gavins Point 

Segment

Sediment load data at the Maskell site within the Gavins 

Point Segment were difficult to interpret during the high 

streamflows as well as the more typical streamflows that followed. It was expected that sediment transport in the Gavins 

Point Segment would differ from that in the Channelized 

Segment because of the differences in the hydraulic conditions 

(as characterized by velocity and depth, table 4) both during 

and after the flood; however, much of the suspended-sediment 

data collected in 2011 resulted in sediment loads that seemed 

unreasonably large when compared to the next site downstream. In addition to being considerably coarser (table 1–1), 

these questionable suspended-sediment loads at the Maskell 

site were consistently greater than those at the Sioux City site 

by hundreds of thousands of tons. As a result, it was presumed 

that these suspended-sediment samples were compromised 

by incorrect sampler contact with the streambed and were 

subsequently omitted from the analyses (Galloway and others, 

2013; loads “not calculated” in table 4). In addition, suspended 

samples at the Maskell site in 2012 were collected more 

carefully. The sampling protocol was adjusted at this site to 

direct that the suspended-sediment sampler was only lowered 

to within 3 ft of the bottom (as determined by prior bedload 

sampling) and that a sample be discarded and recollected for 

any verticals at which the sampling crew suspected contact of 

the sampler with the streambed. Despite these efforts, three of 

seven 2012 samples from the Maskell site still exhibited much 

greater sediment loads when compared to the other Maskell 

samples and all of the Sioux City samples (table 4, fig. 3). 

Although it is possible that the samples were again compromised by inclusion of streambed sediments, it seems much 

less likely than in 2011.

To retain these sediment-load results in the dataset for 

subsequent analyses, a reasonable explanation for these seemingly episodic increases was needed. One potential explanation 

that is supported by anecdotal and bathymetric evidence is the 

erosion of a large sandbar directly upstream from the Maskell 

site. Coincidentally, bathymetric data were collected repeatedly 

just upstream from the sampling location (fig. 10 in Schenk and 

others, 2014). These bathymetric data indicate the formation 

of a sandbar near the left bank between December 2010 and 

November 2011, coinciding with the high streamflows of 2011. 

Subsequent bathymetric data from March 2012 show a narrowing of that sandbar, indicating erosion had taken place along the 

edges of the bar. It is reasonable to assume that this erosion was 

episodic and that much of this eroded material probably redeposited at points in the channel downstream from the sandbar; 

however, given the proximity of the sampling location to an 

eroding sandbar, collected samples may have captured some of 

this eroded material before it redeposited, thereby contributing 

to the unexpectedly high sediment loads at the site.

Contribution of Bedload to Total Load

In many fluvial sediment studies, bedload is not included 

in the monitoring design because of the practical limitations 

associated with collecting a bedload sample and the uncertainty that accompanies bedload data. Instead, sediment characteristics are derived from the results of suspended-sediment 

sampling, and the contribution of bedload is often neglected 

by necessity. In this study, bedload data were available, 

although the corresponding uncertainty was large. Nonetheless, these data provide insight into the part of sediment load 

that would otherwise be missed during the extremely high 

streamflows of 2011 as well as more typical streamflows that 

followed through 2012. During the flooding, sediment loads 

for none of the sites were dominated by bedload, with only the 

Maskell site having bedloads that were typically greater than 

10 percent of the total-sediment load (table 4).
Table 4. Measured sediment loads for six Missouri River sites on dates of sample collection, 2011–12. [Load data for for all samples in 2011 from Galloway and others, 2013. ft3/s, cubic feet per second; ft, feet; ft/s, feet per second; ton/d, tons per day; % of total, percent of total-sedim

Date Streamflow conditions Measurement principle Total-sediment load (ton/d) Transp

Type Daily mean streamflow (ft3/s) Mean depth (ft) Mean velocity (ft/s) Suspended-sediment load Bedload Wash load 

ton/d % of total ton/d % of total ton/d % of tot

Missouri River at Washburn, North Dakota (Washburn site) 06/16/2011 High 147,000 25.4 5.1 182,000 100 344 0 182,000 70,000 38 

06/23/2011 High 151,000 26.8 4.9 157,000 99 625 0 158,000 53,800 34 06/30/2011 High 145,000 27.1 4.8 97,500 100 206 0 97,700 45,600 47 07/06/2011 High 143,000 28.8 4.2 115,000 100 164 0 115,000 46,500 40 07/14/2011 High 131,000 26.9 4.4 78,200 99 479 1 78,700 31,900 41 07/27/2011 High 114,000 24.9 4.5 115,000 97 2,790 2 118,000 43,200 37 08/04/2011 High 108,000 23.0 4.2 48,700 94 2,890 6 51,600 16,100 31 08/17/2011 High 88,400 22.5 3.5 26,700 91 2,790 9 29,500 9,600 33 09/08/2011 High 53,600 17.5 2.8 9,550 89 1,100 10 10,700 3,060 29 09/15/2011 High 49,100 15.9 2.8 7,160 97 192 3 7,350 3,440 47 09/22/2011 Typical 30,800 13.9 2.1 2,500 93 199 7 2,700 1,480 55 09/29/2011 Typical 24,300 12.7 1.8 1,770 76 554 24 2,320 1,530 66 05/18/2012 Typical 25,200 8.8 2.5 1,630 84 316 16 1,950 976 50 06/19/2012 Typical 25,000 9.2 2.4 1,080 81 246 18 1,330 809 61 07/10/2012 Typical 21,700 8.2 2.3 2,290 82 503 18 2,790 2,240 80 08/07/2012 Typical 23,100 8.7 2.3 873 64 490 36 1,360 710 52 09/05/2012 Typical 23,400 8.6 2.4 1,010 94 70 6 1,080 721 67 09/25/2012 Typical 19,000 7.5 2.0 616 63 366 37 982 564 57 10/16/2012 Typical 19,800 8.0 2.0 909 50 905 50 1,810 658 36 10/30/2012 Typical 23,200 8.0 2.2 689 33 1,430 67 2,120 482 23 11/06/2012 Typical 23,100 8.0 2.3 1,870 82 423 18 2,290 956 42 

High mean 113,000 23.9 4.1 83,700 97 1,160 3 84,900 32,300 38 

Typical mean 23,500 9.2 2.2 1,390 73 500 27 1,880 1,010 54 
Date

Streamflow conditions Measurement principle

Total-sediment 

load

(ton/d)

Transp

Type

Daily mean 

streamflow 

(ft3/s)

Mean 

depth 

(ft)

Mean 

velocity 

(ft/s)

Suspended-sediment 

load Bedload Wash load 

ton/d % of total ton/d % of total ton/d % of tot

Missouri River at Bismarck, North Dakota (Bismarck site)

06/09/2011 High 138,000 17.7 5.0 278,000 100 1,500 1 279,000 139,000 50 06/15/2011 High 142,000 18.3 5.0 276,000 100 1,270 0 277,000 83,100 30 06/22/2011 High 151,000 20.9 4.6 196,000 99 2,160 1 198,000 93,900 47 07/01/2011 High 146,000 21.6 4.3 165,000 99 2,470 1 167,000 81,500 49 07/05/2011 High 145,000 21.6 4.3 110,000 99 1,340 1 111,000 74,500 67 07/13/2011 High 139,000 21.2 4.2 127,000 98 2,540 2 130,000 65,300 50 07/26/2011 High 120,000 20.4 3.7 82,600 91 8,530 9 91,100 24,300 27 08/04/2011 High 110,000 20.2 3.5 113,000 93 8,890 7 122,000 27,800 23 08/16/2011 High 92,100 19.9 4.2 93,200 96 3,510 4 96,700 18,800 19 09/08/2011 High 56,700 15.6 2.8 21,900 96 871 4 22,800 10,700 47 09/15/2011 High 51,000 14.5 2.8 15,000 96 594 4 15,600 7,680 49 09/22/2011 Typical 34,500 12.0 2.5 5,960 95 343 5 6,300 3,970 63 09/29/2011 Typical 28,200 11.6 2.3 3,050 96 142 4 3,190 2,370 74 05/17/2012 Typical 27,000 12.6 3.3 8,310 99 75 1 8,390 2,670 32 06/19/2012 Typical 27,400 13.3 3.1 6,290 100 20 0 6,310 2,110 33 07/10/2012 Typical 23,700 12.4 2.9 2,620 94 172 6 2,790 1,380 49 08/07/2012 Typical 25,300 12.2 2.8 4,030 94 261 6 4,290 1,700 40 09/05/2012 Typical 23,900 11.3 2.8 4,650 99 46 1 4,700 2,370 50 09/25/2012 Typical 19,800 10.2 2.4 1,760 85 303 15 2,060 1,320 64 10/16/2012 Typical 20,700 10.5 2.4 1,900 88 249 12 2,150 1,450 67 10/30/2012 Typical 21,300 10.4 2.5 2,420 94 148 6 2,570 1,080 42 11/06/2012 Typical 23,500 10.6 2.7 4,060 99 43 1 4,100 1,700 41 

High mean 117,000 19.3 4.0 134,000 97 3,060 3 137,000 57,000 42 

Typical mean 25,000 11.6 2.7 4,100 95 164 5 4,260 2,010 51 

Table 4. Measured sediment loads for six Missouri River sites on dates of sample collection, 2011–12.—Continued[Load data for all samples in 2011 from Galloway and others, 2013. ft3/s, cubic feet per second; ft, feet; ft/s, feet per second; ton/d, tons per day; % of total, percent of total-sediment 
Date Streamflow conditions Measurement principle Total-sediment load (ton/d) Transp

Type Daily mean streamflow (ft3/s) Mean depth (ft) Mean velocity (ft/s) Suspended-sediment load Bedload Wash load 

ton/d % of total ton/d % of total ton/d % of tot

Missouri River near Maskell, Nebraska (Maskell site) 06/23/2011 High 156,000 16.9 3.8 -- -- 13,300 -- -- -- -- 

06/30/2011 High 168,000 16.5 4.8 118,000 89 15,000 11 133,000 58,000 44 07/21/2011 High 179,000 16.1 3.6 -- -- 29,000 -- -- -- -- 08/04/2011 High 161,000 19.7 4.3 168,000 84 32,900 16 201,000 50,300 25 08/18/2011 High 154,000 18.1 4.3 -- -- 27,500 -- -- -- -- 09/01/2011 High 99,000 18.0 3.8 -- -- 16,800 -- -- -- -- 09/15/2011 High 93,500 11.2 4.1 -- -- 27,400 -- -- -- -- 11/02/2011 Typical 43,800 8.2 2.8 -- -- 6,260 -- -- -- -- 05/31/2012 Typical 30,900 7.0 2.4 90,900 96 3,370 4 94,300 5,520 6 06/20/2012 Typical 32,100 7.3 2.9 76,400 97 2,570 3 79,000 7,710 10 07/09/2012 Typical 33,200 6.9 2.4 6,630 70 2,820 30 9,450 3,590 38 08/09/2012 Typical 37,200 10.0 2.0 6,730 68 3,180 32 9,910 2,800 28 09/06/2012 Typical 37,700 9.4 2.0 64,900 96 2,350 3 67,300 15,900 24 10/11/2012 Typical 37,000 8.1 2.3 16,600 81 4,000 19 20,600 7,430 36 11/15/2012 Typical 35,700 7.3 2.4 11,100 78 3,070 22 14,200 3,160 22 

High mean 165,000 18.1 4.6 143,000 86 24,000 14 167,000 54,200 34 

Typical mean 34,800 8.0 2.3 39,000 84 3,050 16 42,100 6,590 23 

Missouri River at Sioux City, Iowa (Sioux City site) 07/01/2011 High 179,000 35.1 6.6 217,000 97 6,070 3 223,000 59,400 27 

08/05/2011 High 164,000 30.8 6.0 163,000 95 9,450 5 172,000 58,800 34 08/19/2011 High 160,000 32.8 5.2 163,000 95 9,140 5 172,000 58,800 34 09/02/2011 High 101,000 36.8 5.1 54,800 91 5,100 9 59,900 25,300 42 09/16/2011 High 94,300 25.9 6.2 59,600 92 5,210 8 64,800 26,200 40 11/01/2011 Typical 42,500 14.8 5.3 46,200 91 4,420 9 50,600 17,900 35 06/01/2012 Typical 44,500 18.7 4.4 26,600 92 2,410 8 29,000 24,300 84 06/19/2012 Typical 34,200 14.2 3.7 12,700 89 1,500 11 14,200 11,900 84 07/10/2012 Typical 33,800 16.0 3.2 13,800 94 946 6 14,700 7,430 51 08/10/2012 Typical 37,800 17.4 3.3 17,500 91 1,760 9 19,300 9,110 47 

Table 4. Measured sediment loads for six Missouri River sites on dates of sample collection, 2011–12.—Continued[Load data for all samples in 2011 from Galloway and others, 2013. ft3/s, cubic feet per second; ft, feet; ft/s, feet per second; ton/d, tons per day; % of total, percent of total-sediment 
Date

Streamflow conditions Measurement principle

Total-sediment 

load

(ton/d)

Transp

Type

Daily mean 

streamflow 

(ft3/s)

Mean 

depth 

(ft)

Mean 

velocity 

(ft/s)

Suspended-sediment 

load Bedload Wash load 

ton/d % of total ton/d % of total ton/d % of tot

Missouri River at Sioux City, Iowa (Sioux City site)—Continued

09/07/2012 Typical 37,700 17.2 3.3 14,100 89 1,820 11 15,900 7,390 46 

10/12/2012 Typical 37,300 20.1 2.8 26,000 98 549 2 26,500 11,000 42 11/16/2012 Typical 36,000 18.5 3.0 28,700 97 902 3 29,600 17,300 58 

High mean 140,000 32.3 5.8 131,000 94 6,990 6 138,000 45,700 36 

Typical mean 38,000 17.1 3.6 23,200 93 1,790 7 25,000 13,300 56 

Missouri River at Omaha, Nebraska (Omaha site)

07/08/2011 High 190,000 29.9 8.2 399,000 99 3,870 1 403,000 95,800 24 

07/18/2011 High 191,000 31.3 8.0 184,000 98 2,620 1 187,000 134,000 72 08/01/2011 High 186,000 29.3 7.4 119,000 97 3,990 3 123,000 85,700 70 08/15/2011 High 168,000 30.7 7.1 224,000 98 3,930 2 228,000 76,000 33 08/29/2011 High 132,000 33.8 5.0 73,800 91 7,020 9 80,800 45,800 57 09/12/2011 High 102,000 31.3 4.2 41,300 90 4,710 10 46,000 27,700 60 10/31/2011 Typical 47,300 16.9 3.8 20,600 88 2,880 12 23,500 14,400 61 

High mean 162,000 31.1 6.7 174,000 96 4,360 4 178,000 77,500 53 

Missouri River at Nebraska City, Nebraska (Nebraska City site)

06/21/2011 High 195,000 33.6 7.3 225,000 96 9,940 4 235,000 201,000 86 06/27/2011 High 193,000 36.9 7.0 257,000 94 16,100 6 273,000 235,000 86 07/19/2011 High 141,000 36.5 5.3 78,800 87 12,200 13 91,000 78,000 86 08/02/2011 High 144,000 36.0 4.1 110,000 92 9,980 8 120,000 73,500 61 08/16/2011 High 136,000 29.7 4.7 91,100 93 6,960 7 98,100 49,100 50 08/30/2011 High 110,000 39.8 3.7 61,200 90 6,870 10 68,100 40,900 60 09/13/2011 High 93,300 30.3 4.1 55,900 94 3,360 6 59,300 34,600 58 11/03/2011 Typical 54,200 17.0 4.2 50,300 95 2,380 5 52,700 26,300 50 

High mean 145,000 34.7 5.2 126,000 92 9,340 8 135,000 102,000 70 

Table 4. Measured sediment loads for six Missouri River sites on dates of sample collection, 2011–12.—Continued[Load data for all samples in 2011 from Galloway and others, 2013. ft3/s, cubic feet per second; ft, feet; ft/s, feet per second; ton/d, tons per day; % of total, percent of total-sediment 
14 Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12

rol14-EMNR00-0066 Rus Figure 2

EXPLANATION

Wash load

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100,000

150,000

200,000

250,000

0

50,000

100,000

150,000

200,000

250,000

0

50,000

100,000

150,000

200,000

250,000

0

50,000

100,000

150,000

200,000

250,000

A. Washburn

B. Bismarck

May June July August September October November

5 10 15 20 25 5 10 15 20 25 5 10 15 20 25 5 10 15 20 25 5 10 15 20 25 5 10 15 20 25 5 10 15 20

Month and date

C. Maskell

D. Sioux City

E. Omaha

F. Nebraska City

Figure 2. Time series of total-sediment load and daily mean streamflow of Missouri River, selected 

sites, 2011. 
Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–2012 15

rol14-EMNR00-0066 Rus Figure 3

EXPLANATION

Wash load

Bed-material load

Streamflow

0

20,000

40,000

60,000

80,000

100,000

Sediment load, in tons per day

Daily mean streamflow, in cubic feet per second

0

4,000

8,000

12,000

16,000

20,000

0

4,000

8,000

12,000

16,000

20,000

0

20,000

40,000

60,000

80,000

100,000

0

10,000

20,000

30,000

40,000

50,000

60,000

0

10,000

20,000

30,000

40,000

50,000

60,000

0

10,000

20,000

30,000

40,000

50,000

60,000

0

10,000

20,000

30,000

40,000

50,000

60,000

May June July August September October November

5 10 15 20 25 5 10 15 20 25 5 10 15 20 25 5 10 15 20 25 5 10 15 20 25 5 10 15 20 25 5 10 15 20

Month and date

A. Washburn

B. Bismarck

C. Maskell

D. Sioux City

Figure 3. Time series of total-sediment load and daily mean streamflow of Missouri River, selected sites, 2012.
16 Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12

Interestingly, when streamflows returned to more typical conditions in the Garrison Segment, bedload became 

more important at the Washburn site—increasing from a 

high-streamflow mean of 3 percent to a typical-streamflow 

mean of 27 percent of the total load. However, bedload at the 

Bismarck site remained at approximately 5 percent of the total 

load (table 4). Some of this difference between sites may be 

explained by higher velocities at the Bismarck site during typical conditions (table 4) that are likely able to suspend some 

of the materials that otherwise traveled as bedload past the 

Washburn site.

Even though the amount of bedload at the Maskell site in 

the Gavins Point Segment did not vary greatly during typicalstreamflow conditions, the proportion of bedload relative to 

total load was quite variable. As before, the presumed erosion 

of a recently formed sandbar likely added large amounts of 

locally resuspended material, which may not have remained 

suspended beyond the local scale but was within the sampling zone of the Maskell site, thereby affecting the bedload 

proportion. For three 2012 samples that were much higher in 

total-sediment load, bedload made up only 3 to 4 percent of 

the total load (table 4); however, for the other 4 samples from 

2012 not believed to be affected by sandbar erosion, bedload 

made up 26 percent of the total load, on average.

At the Sioux City site in the Channelized Segment, 

bedload was generally lower in magnitude as compared to the 

Gavins Point Segment, regardless of streamflow conditions. 

The average bedload percentage was 7 percent of total-sediment load overall.

Changes in Transport Mechanisms Between the 

Gavins Point and Channelized Segments

The contrast in relative bedload contribution between 

the Maskell site in the Gavins Point Segment and the Sioux 

City site in the Channelized Segment likely reflects changing hydraulic conditions in the Channelized Segment. During typical-streamflow conditions, the hydraulic area of 

cross-sections in the Channelized Segment is constricted 

by 20 to 30 percent compared to counterparts in the Gavins 

Point Segment, thereby producing velocity increases of 30 to 

50 percent. These velocity increases led to greater sedimenttransport capacity within the stream channel through turbulent 

mixing. The greater turbulence more effectively resuspends 

bed sediments within the water column. As bedload sediments 

encounter this turbulence as they enter the Channelized Segment, some of these sediments enter suspension, though they 

still remain part of the bed-material load (table 3). This may in 

part explain the smaller bedloads observed at the Sioux City 

site as compared to the Maskell site (table 4).

This additional turbulent mixing may also convert bedmaterial load into wash load. This conversion becomes important in the context of habitat restoration because sediments in 

the wash load are effectively unavailable for creating sandbars 

and other bedforms; however, this pattern was not consistently 

manifested by differences between the sediment loads of the 

Maskell and Sioux City sites during typical-streamflow conditions. Wash loads at Sioux City were, on average, 6,000 tons 

per day (ton/d) higher than at Maskell (table 4, fig. 3). Some 

of this increase is related to contributions from the Big Sioux 

River. Though the average decrease in bed-material load 

between Maskell and Sioux City was 23,800 ton/d during typical streamflows, this trend likely was affected by the localized 

sandbar erosion at the Maskell site that may have contributed 

large amounts of bed-material load to a subset of samples 

(fig. 3). When that subset of samples is omitted, bed-material 

load increased from the Maskell site to the Sioux City site by 

2,000 ton/d, on average. As a result, the actual amount of bedmaterial load that gets converted to wash load as it enters the 

Channelized Segment is not well understood.

Sediment Load Estimates

Because of the difficulty in obtaining a high-quality 

bedload sample, the MEP, specifically the BORAMEP model 

(Holmquist-Johnson and others, 2009), was used as an alternative approach for estimating bed-material loads. This model 

relies on some overlap between the suspended-sediment grainsize distribution (table 1–1) and the bed-material grain-size distribution (table 1–3). A 5-percent overlap was used by default 

with 1-percent overlap used for some samples dominated by 

wash load; however, several samples had less than 1 percent 

overlap in grain size, and thus loads could not be estimated for 

those samples. Using the samples collected in 2011, Galloway 

and others (2013) determined that the MEP tended to overpredict total-sediment load by 19 percent on average, and bedload 

by 133 percent, when compared to measured values (table 5). 

In addition to practical limitations with the bedload sampler, Galloway and others (2013) suggested that results were 

affected both by supply limitations and the potential existence 

of streamflow in the upper-flow regime—where the streambed is characterized by plane-bed or anti-dune configurations 

(van Rijn, 1984). The transition into plane-bed or anti-dune 

transport would have greatly reduced the amount of bedload 

captured by the bedload samplers, thereby resulting in measurements less than the MEP estimates.

Sediment loads estimated by the MEP from typicalstreamflow samples for this report also were greater than 

measured values (table 5, fig. 4). On average, the MEPestimated total-sediment load was 21 percent greater than 

measured during the typical-streamflow conditions. As with 

the 2011 flooding, much of the difference is associated with 

the characterization of bedload (fig. 4B). Although the bedload 

differences varied considerably in magnitude, MEP-estimated 

bedloads were greater than measured in 23 of 28 samples 

during typical-streamflow conditions with an average difference of 99 percent. Limitations of the MEP technique 

in streams with coarse streambeds relative to the grains in 

suspension became apparent at the Washburn site subsequent 

to the 2011 flooding. Little overlap in grain-size distributions 
Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–2012 17

Table 5. Sediment loads estimated by the Modified-Einstein Procedure for six Missouri River sites, 2011–12.

[Load data for all samples in 2011 from Galloway and others, 2013. MEP, Modified-Einstein Procedure; --, not enough overlap in grain sizes to compute]

Date Streamflow 

conditions

MEP estimated load, in tons per day Percent difference between measured and 

MEP estimated load1

Bed-material load Bedload Total-sediment load Bed-material load Bedload Total-sediment load

Missouri River at Washburn, North Dakota (Washburn site)

06/16/2011 High 170,000 58,000 240,000 -41 -198 -27

06/23/2011 High 143,000 40,000 197,000 -32 -194 -22

06/30/2011 High 80,900 28,500 126,000 -43 -197 -25

07/06/2011 High 83,800 15,000 130,000 -20 -196 -12

07/14/2011 High 61,400 15,100 93,300 -27 -188 -17

07/27/2011 High 86,600 15,000 130,000 -15 -137 -10

08/04/2011 High 44,400 11,800 60,500 -22 -121 -16

08/17/2011 High 26,400 9,300 36,000 -28 -108 -20

09/08/2011 High 14,400 7,950 17,500 -62 -151 -48

09/15/2011 High 7,690 3,940 11,100 -65 -181 -41

09/22/2011 Typical 2,720 1,700 4,200 -76 -158 -43

09/29/2011 Typical 503 260 2,030 45 72 13

05/18/2012 Typical -- -- -- -- -- --

06/19/2012 Typical 1,000 730 1,810 -64 -99 -31

07/10/2012 Typical -- -- -- -- -- --

08/07/2012 Typical -- -- -- -- -- --

09/05/2012 Typical -- -- -- -- -- --

09/25/2012 Typical -- -- -- -- -- --

10/16/2012 Typical 707 461 1,370 49 65 28

10/30/2012 Typical -- -- -- -- -- --

11/06/2012 Typical -- -- -- -- -- --

High mean 71,900 20,500 104,000 -36 -170 -24

Typical mean 1,230 788 2,350 -12 -30 -8

Missouri River at Bismarck, North Dakota (Bismarck site)

06/09/2011 High 202,000 63,000 341,000 -36 -191 -20

06/15/2011 High 257,000 64,000 340,000 -28 -192 -20

06/22/2011 High 142,000 40,000 236,000 -31 -180 -18

07/01/2011 High 127,000 43,000 208,000 -38 -178 -22

07/05/2011 High 48,800 13,000 123,000 -28 -163 -10

07/13/2011 High 87,100 25,000 152,000 -30 -163 -16

07/26/2011 High 83,900 25,400 108,000 -23 -99 -17

08/04/2011 High 99,400 14,000 127,000 -5 -45 -4

08/16/2011 High 99,400 24,800 118,000 -24 -150 -20

09/08/2011 High 16,800 5,600 27,500 -33 -146 -19

09/15/2011 High 11,900 4,600 19,600 -40 -154 -23

09/22/2011 Typical -- -- -- -- -- --

09/29/2011 Typical 2,360 1,680 4,730 -97 -169 -39

05/17/2012 Typical 10,500 4,890 13,200 -59 -194 -45

06/19/2012 Typical 7,850 3,670 9,960 -61 -198 -45

07/10/2012 Typical 3,440 2,200 4,820 -84 -171 -53
18 Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12

Date Streamflow 

conditions

MEP estimated load, in tons per day Percent difference between measured and 

MEP estimated load1

Bed-material load Bedload Total-sediment load Bed-material load Bedload Total-sediment load

Missouri River at Bismarck, North Dakota (Bismarck site)—Continued

08/07/2012 Typical 4,880 2,550 6,580 -61 -163 -42

09/05/2012 Typical 4,950 2,670 7,320 -72 -193 -44

09/25/2012 Typical 1,910 1,470 3,230 -88 -132 -44

10/16/2012 Typical -- -- -- -- -- --

10/30/2012 Typical 3,090 1,750 4,170 -70 -169 -47

11/06/2012 Typical 5,050 2,690 6,750 -71 -194 -49

High mean 107,000 29,300 164,000 -29 -150 -17

Typical mean 4,890 2,620 6,750 -74 -180 -45

Missouri River near Maskell, Nebraska (Maskell site)

06/23/2011 High -- -- -- -- -- --

06/30/2011 High 103,000 43,000 161,000 -31 -97 -19

07/21/2011 High -- -- -- -- -- --

08/04/2011 High 194,000 76,000 244,000 -25 -79 -19

08/18/2011 High -- -- -- -- -- --

09/01/2011 High -- -- -- -- -- --

09/15/2011 High -- -- -- -- -- --

11/02/2011 Typical -- -- -- -- -- --

05/31/2012 Typical 113,000 28,100 119,000 -24 -157 -23

06/20/2012 Typical 100,000 31,600 108,000 -34 -170 -31

07/09/2012 Typical 5,740 2,700 9,330 2 4 1

08/09/2012 Typical 5,620 1,690 8,420 23 61 16

09/06/2012 Typical 51,200 2,200 67,100 0 7 0

10/11/2012 Typical 13,700 4,500 21,100 -4 -12 -2

11/15/2012 Typical 11,300 3,400 14,500 -3 -10 -2

High mean 149,000 59,500 203,000 -28 -88 -19

Typical mean 42,900 10,600 49,600 -6 -40 -6

Missouri River at Sioux City, Iowa (Sioux City site)

07/01/2011 High 171,000 13,000 230,000 -4 -73 -3

08/05/2011 High 171,000 67,000 230,000 -40 -151 -29

08/19/2011 High 139,000 35,000 198,000 -21 -117 -14

09/02/2011 High 51,600 22,100 76,900 -39 -125 -25

Table 5. Sediment loads estimated by the Modified-Einstein Procedure for six Missouri River sites, 2011–12.—Continued

[Load data for all samples in 2011 from Galloway and others, 2013. MEP, Modified-Einstein Procedure; --, not enough overlap in grain sizes to compute]
Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–2012 19

Date Streamflow 

conditions

MEP estimated load, in tons per day Percent difference between measured and 

MEP estimated load1

Bed-material load Bedload Total-sediment load Bed-material load Bedload Total-sediment load

Missouri River at Sioux City, Iowa (Sioux City site)—Continued

11/01/2011 Typical 49,200 20,900 67,100 -40 -130 -28

06/01/2012 Typical -- -- -- -- -- --

06/19/2012 Typical -- -- -- -- -- --

07/10/2012 Typical 10,200 3,800 17,600 -33 -120 -18

08/10/2012 Typical 210,800 22,400 219,900 2-6 2-31 -3

09/07/2012 Typical 29,630 22,900 217,000 2-12 2-46 -7

10/12/2012 Typical 18,000 3,000 29,000 -15 -138 -9

11/16/2012 Typical 14,300 2,900 31,600 -15 -105 -7

High mean 117,000 31,500 163,000 -27 -120 -18

Typical mean 18,700 5,980 30,400 -20 -95 -12

Missouri River at Omaha, Nebraska (Omaha site)

07/08/2011 High 435,000 132,000 531,000 -35 -189 -27

07/18/2011 High 94,900 45,000 229,000 -57 -178 -20

08/01/2011 High 65,000 32,000 151,000 -54 -156 -20

08/15/2011 High 297,000 149,000 373,000 -65 -190 -48

08/29/2011 High 50,500 22,500 96,300 -36 -105 -18

09/12/2011 High 22,900 9,300 50,600 -22 -66 -10

10/31/2011 Typical 12,400 6,200 26,800 -31 -73 -13

High mean 161,000 65,000 238,000 -45 -150 -24

Missouri River at Nebraska City, Nebraska (Nebraska City site)

06/21/2011 High -- -- -- -- -- --

06/27/2011 High 49,700 28,000 285,000 -26 -54 -4

07/19/2011 High -- -- -- -- -- --

08/02/2011 High 55,600 19,000 129,000 -18 -62 -7

08/16/2011 High 92,200 49,900 141,000 -61 -151 -36

08/30/2011 High 29,600 9,300 70,500 -8 -30 -3

09/13/2011 High 34,900 13,600 69,500 -34 -121 -16

11/03/2011 Typical 37,000 13,000 63,300 -33 -138 -18

High mean 52,400 24,000 139,000 -29 -84 -13

1

Calculation of percent difference is: 100 times (x1 - x2) / (0.5 times (x1 + x2)), where x1 equals measured load component, x2 equals MEP estimated 

load component.

2

Grain-size distribution data from the July 2012 suspended sample were used for MEP computations in lieu of missing grain-size data during this sample.

Table 5. Sediment loads estimated by the Modified-Einstein Procedure for six Missouri River sites, 2011–12.—Continued

[Load data for all samples in 2011 from Galloway and others, 2013. MEP, Modified-Einstein Procedure; --, not enough overlap in grain sizes to compute]
20 Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12

rol14-EMNR00-0066 Rus Figure 4

Line of equal value

Line of equal value

EXPLANATION

100

1,000

10,000

100,000

1,000,000

100 1,000 10,000 100,000 1,000,000

100 1,000 10,000 100,000 1,000,000

100

1,000

10,000

100,000

1,000,000

Measured bedload, in tons per day

MEP estimated total-sediment load, in tons per day MEP estimated bedload, in tons per day

Measured total-sediment load, in tons per day

Washburn, high streamflow

Washburn, typical streamflow

Bismarck, high streamflow

Bismarck, typical streamflow

Maskell, high streamflow

Maskell, typical streamflow

Sioux City , high streamflow

Sioux City , typical streamflow

Omaha, high streamflow

Omaha, typical streamflow

Nebraska City, high streamflow

Nebraska City, typical streamflow

Site name and type A

B

Figure 4. Relations of sediment loads estimated by the Modified-Einstein Procedure (MEP) to measured loads for A, total-sediment 

load; and B, bedload, for selected Missouri River sites, 2011–12.
Summary 21

of suspended-sediment load and bed material was measured in 

samples collected during the typical-streamflow conditions at 

the Washburn site; hence, MEP estimates could only be computed for 4 of 11 samples. Unfortunately, grain-size distributions were not available for two samples collected at the Sioux 

City site in August and September 2012. To compute MEP 

estimates for these samples, the suspended grain-size distributions of the July 2012 sample were applied to the SSC values 

for those two samples instead. It is readily acknowledged that 

this substitution introduced a large amount of uncertainty into 

MEP estimates from those two samples.

The differences between MEP-derived sediment loads 

and measured sediment loads pose a dilemma in understanding Missouri River sediment transport. The measured data may 

be missing some of the bed-material load that is transported 

through the unsampled zone near the streambed, thereby leading to an underprediction of the true sediment load. Conversely, 

the MEP relies on assumptions of ample sediment supplies that 

may not be valid in the Missouri River, which would lead to an 

overprediction of sediment load. The reliance on this assumption combined with the uncertainty associated with sampling 

complicates the determination of the correct sediment load; 

however, both techniques tended to produce total-load and 

bed-material-load values that agreed within the same order of 

magnitude, and for many applications this level of uncertainty 

is adequate. Furthermore, the development of newer techniques 

for estimating bedload using field measurements, such as the 

use of time-sequenced bathymetric data (Nittrouer and others, 

2008; McElroy and Mohrig, 2009; Abraham and others, 2011) 

may be useful for reducing the uncertainties associated with 

quantifying sediment-load components.

Summary

During 2011, the Missouri River experienced flooding 

caused by a combination of above-normal snowpack in headwater regions of Montana and Wyoming, near record snowfall 

and wet soil conditions in North and South Dakota, and record 

rainfall in May across the upper Missouri River Basin. Several 

reports have already examined the characteristics of sediment 

transport associated with the 2011 flooding on the Missouri 

River. The emphasis of this report is to compare sediment 

transport in 2011 to that of sediment transport in 2012, a 

year characterized by more typical streamflows. As part of a 

cooperative effort between the U.S. Geological Survey and 

the U.S. Army Corps of Engineers, sediment samples were 

collected at six sites on the Missouri River: two between Lake 

Sakakawea and Lake Oahe in North Dakota from what was 

designated as the Garrison Segment ; one in the free-flowing, 

nonchannelized length of the river downstream from Lewis 

and Clark Lake along the Nebraska-South Dakota border in 

what was designated as the Gavins Point Segment; and three 

in the channelized length of the river along the NebraskaIowa border, which is part of the designated Channelized 

Segment. Sampling took place from June 2011 to November 

2012 at various time intervals among the six sites. Suspendedsediment, bed-material, and bedload samples were collected in 

tandem with streamflow measurements during each sampling 

event. Sediment samples were analyzed for concentration, 

weight, and grain-size distribution. Using streamflow rates and 

these sediment data, the measured sediment loads were computed. Additionally, the Modified-Einstein Procedure (MEP) 

was used to estimate sediment loads for those same samples.

Relative to the high-streamflow event in 2011, samples 

collected in 2012 during typical streamflows were associated 

with much lower streamflows. As expected for this decrease, 

the sediment loads measured in 2012 during typical streamflows also were much lower than those measured during the 

2011 flooding. It also was anticipated that sediment supplies 

may have been depleted during the extreme and prolonged 

flooding and might take several years to recover. Some evidence of sediment depletion existed at some sites, and may 

suggest a shift out of dynamic equilibrium following the 2011 

flood.

Bedload measurements are not typically included in a 

sediment monitoring program, and their inclusion in this study 

provided some insight to the relative contribution of bedload 

in the Missouri River. During the flooding, sediment loads for 

none of the sites were dominated by bedload, with only the 

Maskell site having bedloads that were typically greater than 

10 percent of the total load. Following the flooding, bedload 

increased to an average 27 percent of the total load at one site 

in the Garrison Segment but not for the next site downstream, 

possibly as the result of increased velocity at the downstream 

site. In the Gavins Point Segment, the relative amount of bedload varied greatly in response to the presumed sandbar erosion 

there, but made up an average 26 percent of the total load when 

this erosion was not suspected to be active. Bedload decreased 

to an average 7 percent of the total load during typical streamflows as it entered the Channelized Segment. Stream velocities 

increased by 30 to 50 percent in the Channelized Segment, 

thereby increasing the turbulent mixing potential of the river 

that likely suspended some of the bedload. This turbulent mixing also may convert bed-material load into wash load, thereby 

rendering those sediments unavailable for creating sandbars 

and other bedforms. Though some of the sampling data support 

this premise, it was not consistently manifested by differences 

between the sediment loads of the Maskell and Sioux City sites 

during typical-streamflow conditions.

Because of the difficulty in obtaining a high-quality 

bedload sample, the MEP was used as an alternative approach 

for estimating sediment loads. The MEP tended to predict 

greater total-sediment loads than the measured values, averaging 19 percent greater during high streamflows and 21 percent 

during typical streamflows. These differences may be the 

result of a sediment deficit in the Missouri River that leads to 

an overprediction by the MEP, the unsampled zone above the 

streambed that leads to an underprediction by the suspended 

sampler, or general uncertainty associated with the sampling 

approach.
22 Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12

The differences between MEP-derived sediment loads 

and measured sediment loads pose a dilemma in understanding 

Missouri River sediment transport. Though it is not clear which 

of the two techniques is better or more accurate, the two values 

for sediment load tend to be within an order of magnitude 

of one another, and this may be adequate for many sediment 

applications. Furthermore, newer techniques for estimating 

bedload have been developed and may be useful for reducing 

uncertainties in quantifying sediment transport in the future.

References Cited

Abraham, David, Kuhnle, R.A., and Odgaard, A.J., 2011, 

Validation of bed-load transport measurements with timesequenced bathymetric data: Journal of Hydraulic Engineering, v. 137, no. 7, p. 723–728.

Alexander, J.S., Jacobson, R.B., and Rus, D.L., 2013, Sediment transport and deposition in the lower Missouri River 

during the 2011 flood: U.S. Geological Survey Professional 

Paper 1798–F, 27 p., accessed December 17, 2013, at http://

dx.doi.org/10.3133/pp1798F.

Biedenharn, D.S., Soileau, R.S., Hubbard, L.C., Hoffman, 

P.H., Thorne, C.R., Bromley, C.C., and Watson, C.C., 

2001, Missouri River—Fort Peck Dam to Ponca State Park 

geomorphological assessment related to bank stabilization: 

U.S. Army Corps of Engineers, Omaha District Paper 74, 

136 p.

Carlston, C.W., 1969, Longitudinal slope characteristics of 

rivers of the midcontinent and the Atlantic east gulf slopes: 

Bulletin of the International Association of Scientific 

Hydrology, v. 14, no.4, p. 21–31.

Chen, A.H., Rus, D.L., and Stanton, C.P., 1999, Trends in 

channel gradation in Nebraska streams: U.S. Geological 

Survey Water-Resources Investigations Report 99–4103, 

29 p., 1 pl.

Church, M., 2006, Bed material transport and the morphology of alluvial river channels: Annual Reviews in Earth and 

Planetary Science, v. 34, p. 325–354.

Colby, B.R., and Hembree, C.H., 1955, Computation of total 

sediment discharge, Niobrara River near Cody, Nebr.: 

U.S. Geological Survey Water-Supply Paper 1357, 187 p.

Colby, B.R., and Hubbell, D.W., 1967, Simplified methods 

for computing total sediment discharge with the modified 

Einstein procedure: U.S. Geological Survey Water-Supply 

Paper 1593, 17 p.

Davis, B.E., 2005, A guide to the proper selection and use of 

federally approved sediment and water-quality samplers: 

U.S. Geological Survey Open-File Report 2005–1087, 20 p. 

Edwards, T.K., and Glysson, G.D., 1999, Field methods for 

measurement of fluvial sediment: U.S. Geological Survey 

Techniques of Water-Resources Investigations, book 3, 

chap. C2, 89 p.

Einstein, H.A., 1950, The bedload function for sediment 

transportation in open channel flows: U.S. Department of 

Agriculture, Technical Bulletin 1026, 70 p.

Galloway, J.M., Rus, D.L., and Alexander, J.S., 2013, Characteristics of sediment transport at selected sites along the 

Missouri River during the high-flow conditions of 2011: 

U.S. Geological Survey Scientific Investigations Report 

2013–5006, 31 p.

Gray, J.R., Laronne, J.B., and Marr, J.D.G., 2010, Bedloadsurrogate monitoring technologies: U.S. Geological Survey 

Scientific Investigations Report 2010–5091, 37 p. [Also 

available at http://pubs.usgs.gov/sir/2010/5091.]

Grigg, N., McCarthy, C., Lawrence, B., and Ockerman, D., 

2012, Review of the regulation of the Missouri River mainstem reservoir system during the flood of 2011: Omaha, 

Nebraska, Missouri River Independent Review Panel report 

to the U.S. Army Corps of Engineers, Omaha District, 93 p.

Guy, H.P., 1969, Laboratory theory and methods for sediment 

analysis: U.S. Geological Survey Techniques of WaterResources Investigations Reports, book 5, chap. C1, 58 p.

Holmes, R.R., Jr., Wiche, G.J., Koenig, T.A., and Sando, 

S.K., 2013, Peak streamflows and runoff volumes for the 

central United States, February through September, 2011: 

U.S. Geological Survey Professional Paper 1798–C, 60 p., 

accessed January 5, 2015, at http://pubs.usgs.gov/pp/1798c/.

Holmquist-Johnson, Chris, Raff, David, and Russell, Kendra, 

2009, Bureau of Reclamation Automated Modified Einstein Procedure (BORAMEP) program for computing total 

sediment discharge: U.S. Bureau of Reclamation Technical 

Service Center, 48 p., accessed August 11, 2015, at http://

www.usbr.gov/tsc/sediment/model/boramep/index.html.

Horowitz, A.J., 2003, An evaluation of sediment rating curves 

for estimating suspended sediment concentrations for 

subsequent flux calculations: Hydrological Processes, v. 17, 

p. 3387–3409.

Jacobson, R.B., Blevins, D.W., and Bitner, C.J., 2009, Sediment regime constraints on river restoration—An example 

from the lower Missouri River: Geological Society of 

America Special Paper 451, p. 1–22.

Juracek, K.E., 2014, Geomorphic changes caused by the 2011 

flood at selected sites along the lower Missouri River and 

comparison to historical floods: U.S. Geological Survey 

Professional Paper 1798–H, 15 p., accessed January 5, 

2015, at http://dx.doi.org/10.3133/pp1798H.
References Cited 23

McElroy, Brandon, and Mohrig, David, 2009, Nature of 

deformation of sandy bed forms: Journal of Geophysical 

Research, v. 114, F00A04, 13p.

Mueller, D.K., Schertz, T.L., Martin, J.D., and Sandstrom, 

M.W., 2015, Design, analysis, and interpretation of field 

quality-control data for water-sampling projects: U.S. Geological Survey Techniques and Methods, book 4, chap. C4, 

54 p., accessed July 20, 2015, at http://dx.doi.org/10.3133/

tm4C4.

Mueller, D.S., and Wagner, C.R., 2009, Measuring discharge 

with acoustic Doppler current profilers from a moving boat: 

U.S. Geological Survey Techniques and Methods, book 3, 

chap. A22, 72 p.

National Research Council, 2002, The Missouri River ecosystem—Exploring the prospects for recovery: Washington, 

D.C., National Academies Press, 176 p.

National Research Council, 2011, Missouri River planning—

Recognizing and incorporating sediment management: 

Washington, D.C., National Academies Press, 152 p.

Nittrouer, J.A., Allison, M.A., and Campanella, Richard, 2008, 

Bedform transport rates for the lowermost Mississippi 

River: Journal of Geophysical Research, v. 113, F03004, 

16 p.

Pokrefke, T.J., Abraham, D.A., Hoffman, P.H., Thomas, W.A., 

Darby, S.E., and Thorne, C.R., 1998, Cumulative erosion 

impacts analysis for the Missouri River master water control manual review and update study: U.S. Army Corps of 

Engineers Technical Report CHL-98-7, 288 p.

Porterfield, George, 1972, Computation of fluvial-sediment 

discharge: Techniques of Water-Resources Investigations of 

the U.S. Geological Survey, book 3, chap. C3, 16 p.

Schenk, E.R., Skalak, K.J., Benthem, A.J., Dietsch, B.J., 

Woodward, B.K., Wiche, G.J., Galloway, J.M., Nustad, 

R.A., and Hupp, C.R., 2014, Geomorphic change on the 

Missouri River during the flood of 2011: U.S. Geological 

Survey Professional Paper 1798–I, 25 p., accessed January 5, 2015, at http://dx.doi.org/10.3133/pp1798I.

Skalak, K.J., Benthem, A.J., Schenk, E.R., Hubb, C.R., Galloway, J.M., Nustad, R.A., and Wiche, G.J., 2013, Large dams 

and alluvial rivers in the Anthropocene—The impacts of 

the Garrison and Oahe Dams on the upper Missouri River: 

Anthropocene, v. 2, p. 51–64.

U.S. Army Corps of Engineers, 2012, Post 2011 flood event 

analysis of Missouri River mainstem flood control storage: 

U.S. Army Corps of Engineers, Northwestern Division, 

29 p.

U.S. Geological Survey, 2015, National Water Information 

System (NWISWeb): U.S. Geological Survey database, 

accessed July 29, 2015, at http://waterdata.usgs.gov/nwis/

inventory?multiple_site_no=06341000%2C06342500%2C0

6478526%2C06485500%2C06479010%2C06486000%2C0

6610000%2C06807000&format=station_list.

van Rijn, L.C., 1984, Sediment transport, part III—Bed forms 

and alluvial roughness: Journal of Hydraulic Engineering, 

v. 110, no. 12, p. 1733–1754.

Vining, K.C., Chase, K.J., and Loss, G.R., 2013, General 

weather conditions and precipitation contributing to the 

2011 flooding in the Mississippi River and Red River of the 

North Basins, December 2010 through July 2011: U.S. Geological Survey Professional Paper 1798–B, 22 p.

Williams, G.P., and Wolman, M.G., 1984, Downstream effects 

of dams on alluvial rivers: U.S. Geological Survey Professional Paper 1286, 83 p.
24 Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12
Appendix Tables 25

Appendix Tables
26 Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12

Table 1–1. Suspended-sediment concentrations and grain sizes for six Missouri River sites, 2011–12.

[mg/L, milligram per liter; mm, millimeter; D65, grain-size diameter at which 65 percent of the mass is finer; <, less than; --, not available]

Date

Streamflow 

conditions

Suspendedsediment 

concentration 

(mg/L)

Suspended-sediment fall diameter (grain size) (percent in size range, by weight)

D65 

(mm) Less than 

0.062 mm

0.062 to 

0.125 mm

0.125 to 

0.250 mm

0.250 to 

0.500 mm

0.500 to 

1 mm

1 to 2 mm

Missouri River at Washburn, North Dakota (Washburn site)

06/16/2011 High 458 31 4 27 38 0 0 0.27

06/23/2011 High 384 21 16 55 8 0 0 0.19

06/23/2011 High1 277 29 -- -- -- -- -- --

06/30/2011 High 249 21 25 33 21 0 0 0.20

07/06/2011 High 297 16 21 59 4 0 0 0.18

07/14/2011 High 221 17 19 62 2 0 0 0.18

07/27/2011 High 374 9 26 46 10 9 0 0.21

07/27/2011 High1 437 7 -- -- -- -- -- --

08/04/2011 High 167 13 13 68 3 3 0 0.20

08/17/2011 High 112 19 14 57 10 0 0 0.20

08/17/2011 High1 96 20 -- -- -- -- -- --

09/08/2011 High 66 24 16 52 8 0 0 0.19

09/15/2011 High 54 33 15 45 7 0 0 0.17

09/22/2011 Typical 30 53 19 28 0 0 0 0.10

09/29/2011 Typical 27 75 11 8 6 0 0 <0.062

05/18/2012 Typical 24 40 12 48 0 0 0 0.16

06/19/2012 Typical 16 55 7 31 7 0 0 0.14

07/10/2012 Typical 39 59 39 2 0 0 0 0.07

08/07/2012 Typical 14 58 20 22 0 0 0 0.08

09/05/2012 Typical 16 63 8 5 24 0 0 0.08

09/25/2012 Typical 12 88 2 10 0 0 0 <0.062

10/16/2012 Typical 17 67 1 28 4 0 0 <0.062

10/16/2012 Typical1 16 46 -- -- -- -- -- --

10/30/2012 Typical 11 59 5 36 0 0 0 0.13

11/06/2012 Typical 30 31 16 53 0 0 0 0.17

Missouri River at Bismarck, North Dakota (Bismarck site)

06/09/2011 High 745 38 10 35 17 0 0 0.19

06/15/2011 High 721 18 9 43 28 2 0 0.24

06/22/2011 High 480 22 20 39 19 0 0 0.20

06/22/2011 High1 429 28 -- -- -- -- -- --

07/01/2011 High 418 14 24 39 23 0 0 0.21

07/05/2011 High 280 20 22 52 4 2 0 0.18

07/13/2011 High 338 15 19 49 14 3 0 0.20

07/26/2011 High 255 10 5 65 20 0 0 0.22

08/04/2011 High 380 7 7 48 20 18 0 0.29

08/16/2011 High 375 9 7 37 15 32 0 0.45

08/16/2011 High1 341 10 -- -- -- -- -- --

09/08/2011 High 143 24 23 49 4 0 0 0.17

09/15/2011 High 109 25 24 47 4 0 0 0.17
Appendix Tables 27

Date

Streamflow 

conditions

Suspendedsediment 

concentration 

(mg/L)

Suspended-sediment fall diameter (grain size) (percent in size range, by weight)

D65 

(mm) Less than 

0.062 mm

0.062 to 

0.125 mm

0.125 to 

0.250 mm

0.250 to 

0.500 mm

0.500 to 

1 mm

1 to 2 mm

Missouri River at Bismarck, North Dakota (Bismarck site)—Continued

09/22/2011 Typical 64 48 18 34 0 0 0 0.12

09/29/2011 Typical 40 61 16 11 12 0 0 0.08

05/17/2012 Typical 114 16 13 66 5 0 0 0.19

06/19/2012 Typical 85 22 10 63 5 0 0 0.19

07/10/2012 Typical 41 38 13 42 7 0 0 0.17

08/07/2012 Typical 59 33 7 59 1 0 0 0.18

09/05/2012 Typical 72 33 15 48 4 0 0 0.17

09/25/2012 Typical 33 60 14 13 13 0 0 0.08

10/16/2012 Typical 34 53 22 25 0 0 0 0.10

10/16/2012 Typical1 35 52 -- -- -- -- -- --

10/30/2012 Typical 42 29 14 46 11 0 0 0.18

11/06/2012 Typical 64 24 15 51 10 0 0 0.19

Missouri River near Maskell, Nebraska (Maskell site)

06/23/2011 High 2830 211 24 230 255 20 20 20.34

06/30/2011 High 261 29 14 48 9 0 0 0.18

07/21/2011 High 2760 29 23 232 248 28 20 20.36

08/04/2011 High 386 17 6 42 33 2 0 0.25

08/18/2011 High 2895 27 23 228 258 24 20 20.37

09/01/2011 High 2822 27 23 219 269 22 20 20.38

09/15/2011 High 23,250 22 20 226 253 217 22 20.42

11/02/2011 Typical 22,270 22 20 29 273 216 20 20.43

05/31/2012 Typical 1,090 3 1 15 73 5 3 0.41

05/31/2012 Typical1 599 4 2 18 67 9 0 0.40

06/20/2012 Typical 881 7 1 14 67 9 1 0.41

07/09/2012 Typical 74 33 8 49 10 0 0 0.19

07/09/2012 Typical1 60 29 4 51 16 0 0 0.20

08/09/2012 Typical 67 31 7 36 26 0 0 0.22

09/06/2012 Typical 638 6 1 35 56 2 0 0.35

10/11/2012 Typical 166 20 4 26 42 8 0 0.34

11/15/2012 Typical 115 24 6 59 11 0 0 0.20

Missouri River at Sioux City, Iowa (Sioux City site)

07/01/2011 High 449 22 3 28 22 5 11 0.39

08/05/2011 High 367 23 7 42 26 2 0 0.23

08/19/2011 High 378 23 8 39 27 3 0 0.23

09/02/2011 High 201 34 8 32 23 3 0 0.21

09/16/2011 High 234 27 12 38 20 3 0 0.21

11/01/2011 Typical 403 14 9 44 33 0 0 0.24

06/01/2012 Typical 221 63 10 18 9 0 0 0.07

06/19/2012 Typical 138 49 11 33 7 0 0 0.14

Table 1–1. Suspended-sediment concentrations and grain sizes for six Missouri River sites, 2011–12.—Continued

[mg/L, milligram per liter; mm, millimeter; D65, grain-size diameter at which 65 percent of the mass is finer; <, less than; --, not available]
28 Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12

Date

Streamflow 

conditions

Suspendedsediment 

concentration 

(mg/L)

Suspended-sediment fall diameter (grain size) (percent in size range, by weight)

D65 

(mm) Less than 

0.062 mm

0.062 to 

0.125 mm

0.125 to 

0.250 mm

0.250 to 

0.500 mm

0.500 to 

1 mm

1 to 2 mm

Missouri River at Sioux City, Iowa (Sioux City site)—Continued

07/10/2012 Typical 151 36 12 40 12 0 0 0.18

08/10/2012 Typical 171 -- -- -- -- -- -- --

09/07/2012 Typical 139 -- -- -- -- -- -- --

10/12/2012 Typical 258 16 9 49 26 0 0 0.23

11/16/2012 Typical 295 15 13 58 14 0 0 0.20

Missouri River at Omaha, Nebraska (Omaha site)

07/08/2011 High 778 19 3 32 42 3 1 0.32

07/18/2011 High 356 40 5 27 23 5 0 0.22

08/01/2011 High 237 44 4 24 26 2 0 0.21

08/15/2011 High 493 18 1 21 57 3 0 0.36

08/29/2011 High 207 44 5 21 27 3 0 0.22

09/12/2011 High 150 54 9 18 19 0 0 0.14

10/31/2011 Typical 161 43 13 25 19 0 0 0.17

Missouri River at Nebraska City, Nebraska (Nebraska City site)

06/21/2011 High 427 79 5 4 12 0 0 <0.062

06/27/2011 High 494 75 2 14 7 2 0 <0.062

07/19/2011 High 207 82 4 13 1 0 0 <0.062

08/02/2011 High 283 54 5 14 19 8 0 0.18

08/16/2011 High 248 41 7 25 23 4 0 0.21

08/30/2011 High 206 53 6 30 11 0 0 0.15

09/13/2011 High 222 53 8 23 12 4 0 0.15

11/03/2011 Typical 344 42 4 30 20 4 0 0.20

1

Analytical results associated with a replicate sample.

2

Value is considered erroneous because the result of the sample is presumed to have been compromised by bed-material particles.

Table 1–1. Suspended-sediment concentrations and grain sizes for six Missouri River sites, 2011–12.—Continued

[mg/L, milligram per liter; mm, millimeter; D65, grain-size diameter at which 65 percent of the mass is finer; <, less than; --, not available]
Appendix Tables 29

Table 1–2. Grain sizes and mass of bedload samples for six Missouri River sites, 2011–12.

[mm, millimeter; ton/d, tons per day]

Date

Streamflow 

conditions

Bedload-sediment fall diameter (grain size) (percent in size range, by weight) Measured 

bedload 

(ton/d)

Less than 

0.062 mm

0.062 to 

0.125 mm

0.125 to 

0.250 mm

0.250 to 

0.500 mm

0.500 to 

1 mm

1 to 

2 mm

2 to 

4 mm

4 to 

8 mm

8 to 

16 mm

16 to 

32 mm

Missouri River at Washburn, North Dakota (Washburn site)

06/16/2011 High 0 4 51 34 4 1 1 1 4 0 344

06/23/2011 High 0 3 41 45 3 0 1 1 3 3 625

06/30/2011 High 1 4 54 34 2 0 1 3 1 0 206

07/06/2011 High 0 2 55 35 4 1 0 0 3 0 164

07/14/2011 High 0 5 72 19 2 2 0 0 0 0 479

07/27/2011 High 0 0 24 72 2 1 0 1 0 0 2,790

08/04/2011 High 0 0 11 68 8 2 1 2 4 4 2,890

08/17/2011 High 0 0 13 79 4 2 1 1 0 0 2,790

09/08/2011 High 0 0 7 73 4 3 4 5 4 0 1,100

09/15/2011 High 0 0 1 56 24 4 5 9 1 0 192

09/22/2011 Typical 0 0 4 81 13 2 0 0 0 0 199

09/29/2011 Typical 0 0 3 70 21 2 3 1 0 0 554

05/18/2012 Typical 0 0 8 87 4 1 0 0 0 0 316

06/19/2012 Typical 0 0 12 80 6 1 1 0 0 0 246

07/10/2012 Typical 0 1 17 69 8 3 1 1 0 0 503

08/07/2012 Typical 0 0 27 69 3 1 0 0 0 0 490

09/05/2012 Typical 0 3 25 70 1 1 0 0 0 0 70

09/25/2012 Typical 0 0 12 79 6 2 1 0 0 0 366

10/16/2012 Typical 0 0 29 66 3 1 1 0 0 0 905

10/30/2012 Typical 0 0 21 69 7 2 0 1 0 0 1,430

11/06/2012 Typical 0 0 8 83 7 1 1 0 0 0 423

Missouri River at Bismarck, North Dakota (Bismarck site)

06/09/2011 High 0 3 46 45 4 1 0 1 0 0 1,500

06/15/2011 High 0 2 43 51 3 0 1 0 0 0 1,270

06/22/2011 High 0 1 21 57 14 4 1 2 0 0 2,160

07/01/2011 High 0 1 21 39 33 3 1 1 1 0 2,470

07/05/2011 High 0 2 19 40 30 4 0 2 0 3 1,340

07/13/2011 High 0 1 20 36 34 6 2 1 0 0 2,540

07/26/2011 High 0 0 13 47 27 7 2 2 2 0 8,530

08/04/2011 High 0 1 17 49 19 5 2 1 0 6 8,890

08/16/2011 High 0 0 7 48 26 8 5 4 2 0 3,510

09/08/2011 High 0 0 3 44 29 8 5 4 7 0 871

09/15/2011 High 0 0 5 68 18 5 2 2 0 0 594

09/22/2011 Typical 0 0 4 58 26 7 4 1 0 0 343

09/29/2011 Typical 0 0 1 56 31 8 3 1 0 0 142

05/17/2012 Typical 0 1 53 40 4 2 0 0 0 0 75

06/19/2012 Typical 0 0 3 55 13 8 11 8 2 0 20

07/10/2012 Typical 1 0 10 72 8 5 3 1 0 0 172

08/07/2012 Typical 0 0 18 53 19 6 3 1 0 0 261
30 Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12

Date

Streamflow 

conditions

Bedload-sediment fall diameter (grain size) (percent in size range, by weight) Measured 

bedload 

(ton/d)

Less than 

0.062 mm

0.062 to 

0.125 mm

0.125 to 

0.250 mm

0.250 to 

0.500 mm

0.500 to 

1 mm

1 to 

2 mm

2 to 

4 mm

4 to 

8 mm

8 to 

16 mm

16 to 

32 mm

Missouri River at Bismarck, North Dakota (Bismarck site)—Continued

09/05/2012 Typical 0 0 12 49 18 10 6 5 0 0 46

09/25/2012 Typical 0 0 40 44 9 4 2 1 0 0 303

10/16/2012 Typical 0 0 18 66 10 4 2 0 0 0 249

10/30/2012 Typical 0 0 30 56 8 4 2 0 0 0 148

11/06/2012 Typical 0 0 5 81 8 4 2 0 0 0 43

Missouri River near Maskell, Nebraska (Maskell site)

06/23/2011 High 0 0 10 68 18 3 1 0 0 0 13,300

06/30/2011 High 0 0 12 71 14 2 1 0 0 0 15,000

07/21/2011 High 0 0 8 65 23 2 1 1 0 0 29,000

08/04/2011 High 0 0 15 59 20 3 1 1 1 0 32,900

08/18/2011 High 0 0 13 63 18 4 1 1 0 0 27,500

09/01/2011 High 0 0 7 59 27 4 2 1 0 0 16,800

09/15/2011 High 0 0 9 50 31 4 0 6 0 0 27,400

11/02/2011 Typical 0 0 5 51 32 8 3 1 0 0 6,260

05/31/2012 Typical 0 0 5 51 32 8 3 1 0 0 3,370

06/20/2012 Typical 0 0 9 62 25 2 1 1 0 0 2,570

07/09/2012 Typical 0 0 16 54 25 4 1 0 0 0 2,820

08/09/2012 Typical 0 0 3 37 39 14 6 1 0 0 3,180

09/06/2012 Typical 0 0 5 46 34 10 4 1 0 0 2,350

10/11/2012 Typical 0 0 3 45 40 9 2 1 0 0 4,000

11/15/2012 Typical 0 0 10 61 25 3 1 0 0 0 3,070

Missouri River at Sioux City, Iowa (Sioux City site)

07/01/2011 High 0 0 4 44 30 5 1 1 4 11 6,070

08/05/2011 High 0 0 10 43 18 8 5 4 7 5 9,450

08/19/2011 High 0 0 7 34 18 9 7 5 3 17 9,140

09/02/2011 High 0 0 14 47 16 6 3 3 1 10 5,100

09/16/2011 High 0 1 19 72 2 1 1 1 3 0 5,210

11/01/2011 Typical 0 1 16 77 5 1 0 0 0 0 4,420

06/01/2012 Typical 0 0 4 71 23 1 1 0 0 0 2,410

06/19/2012 Typical 0 0 7 58 28 4 2 0 1 0 1,500

07/10/2012 Typical 0 0 6 65 23 4 0 2 0 0 946

08/10/2012 Typical 0 0 3 65 21 2 0 0 9 0 1,760

09/07/2012 Typical 0 0 7 62 24 5 1 1 0 0 1,820

10/12/2012 Typical 0 0 9 62 23 4 1 1 0 0 549

11/16/2012 Typical 0 0 9 67 21 2 1 0 0 0 902

Table 1–2. Grain sizes and mass of bedload samples for six Missouri River sites, 2011–12.—Continued

[mm, millimeter; ton/d, tons per day]
Appendix Tables 31

Date

Streamflow 

conditions

Bedload-sediment fall diameter (grain size) (percent in size range, by weight) Measured 

bedload 

(ton/d)

Less than 

0.062 mm

0.062 to 

0.125 mm

0.125 to 

0.250 mm

0.250 to 

0.500 mm

0.500 to 

1 mm

1 to 

2 mm

2 to 

4 mm

4 to 

8 mm

8 to 

16 mm

16 to 

32 mm

Missouri River at Omaha, Nebraska (Omaha site)

07/08/2011 High 0 0 3 65 27 4 1 0 0 0 3,870

07/18/2011 High 0 0 3 49 27 11 1 1 0 8 2,620

08/01/2011 High 0 0 5 62 27 5 0 1 0 0 3,990

08/15/2011 High 0 0 10 65 13 4 2 0 0 6 3,930

08/29/2011 High 0 0 8 57 23 5 2 1 4 0 7,020

09/12/2011 High 0 0 15 60 15 4 1 0 5 0 4,710

10/31/2011 Typical 0 0 11 72 9 3 3 1 1 0 2,880

Missouri River at Nebraska City, Nebraska (Nebraska City site)

06/21/2011 High 0 0 2 26 25 20 19 6 2 0 9,940

06/27/2011 High 0 0 1 23 40 22 10 3 1 0 16,100

07/19/2011 High 0 0 3 27 37 18 7 3 5 0 12,200

08/02/2011 High 0 0 4 32 35 17 9 2 1 0 9,980

08/16/2011 High 0 0 5 22 32 19 12 7 3 0 6,960

08/30/2011 High 0 0 19 33 24 15 8 1 0 0 6,870

09/13/2011 High 0 0 12 48 21 12 4 2 1 0 3,360

11/03/2011 Typical 0 0 24 71 3 1 1 0 0 0 2,380

Table 1–2. Grain sizes and mass of bedload samples for six Missouri River sites, 2011–12.—Continued

[mm, millimeter; ton/d, tons per day]
Table 1–3. Grain sizes of bed-material samples for six Missouri River sites, 2011–12. [mm, millimeter; D65, grain-size diameter at which 65 percent of the mass is finer; --, not available] Date Stream- flow conditions Bed-material fall diameter (grain size) (percent in size range, by weight) 

Less than 0.062 mm 0.062 to 0.125 mm 0.125 to 0.250 mm 0.250 to 0.500 mm 0.500 to 1 mm 1 to 2 mm 2 to 4 mm 4 to 8 mm 8 to 16 mm 16 to 32 mm 32 t

63 m

Missouri River at Washburn, North Dakota (Washburn site) 06/16/2011 High 0 2 23 43 8 2 3 5 2 12 0 

06/23/2011 High 0 6 48 38 7 1 0 0 0 0 0 06/30/2011 High 0 4 41 41 5 1 0 1 7 0 0 07/06/2011 High 0 3 33 7 5 1 2 1 14 34 0 07/14/2011 High 0 1 51 15 3 2 2 6 11 9 0 07/27/2011 High 0 2 54 27 3 2 1 4 4 3 0 08/04/2011 High 0 1 38 59 1 0 0 1 0 0 0 08/17/2011 High 0 3 39 52 4 0 0 1 1 0 0 09/08/2011 High 1 8 40 45 5 0 1 0 0 0 0 09/15/2011 High 0 5 70 24 1 0 0 0 0 0 0 09/22/2011 Typical 2 9 74 14 1 0 0 0 0 0 0 09/29/2011 Typical 0 2 44 25 4 1 2 5 7 10 0 05/18/2012 Typical 0 0 31 63 5 0 0 0 0 1 0 06/19/2012 Typical 0 0 12 80 6 1 1 0 0 0 0 07/10/2012 Typical 0 4 33 51 9 2 1 0 0 0 0 08/07/2012 Typical 0 0 33 61 5 1 0 0 0 0 0 09/05/2012 Typical 0 1 65 21 5 4 2 2 0 0 0 09/25/2012 Typical 0 0 31 62 6 0 1 0 0 0 0 10/16/2012 Typical 0 0 32 63 4 0 1 0 0 0 0 10/30/2012 Typical 0 0 30 63 5 1 1 0 0 0 0 11/06/2012 Typical 1 1 39 52 5 1 1 0 0 0 0 

Missouri River at Bismarck, North Dakota (Bismarck site)

06/09/2011 High 0 2 55 41 1 1 0 0 0 0 0 

06/15/2011 High 0 2 42 54 2 0 0 0 0 0 0 06/22/2011 High 0 1 26 65 6 0 1 1 0 0 0 07/01/2011 High 0 0 17 56 25 2 0 0 0 0 0 07/05/2011 High 0 0 10 46 33 4 0 2 0 5 0 07/13/2011 High 0 0 14 42 34 7 2 1 0 0 0 07/26/2011 High 0 1 18 35 30 9 4 3 0 0 0 08/04/2011 High 0 1 18 39 26 6 1 2 0 7 0 
Date

Streamflow 

conditions

Bed-material fall diameter (grain size) (percent in size range, by weight) 

Less than 

0.062 mm

0.062 to 

0.125 mm

0.125 to 

0.250 mm

0.250 to 

0.500 mm

0.500 to 

1 mm 1 to 2 mm 2 to 4 mm 4 to 8 mm 8 to 16 mm 16 to 32 mm 32 t

63 m

Missouri River at Bismarck, North Dakota (Bismarck site)—Continued

09/08/2011 High 0 3 49 24 9 6 4 1 4 0 0 

09/15/2011 High 0 3 43 25 15 6 4 4 0 0 0 09/22/2011 Typical 0 4 63 20 7 2 2 2 0 0 0 09/29/2011 Typical 0 2 50 29 13 4 2 0 0 0 0 05/17/2012 Typical 0 1 86 13 0 0 0 0 0 0 0 06/19/2012 Typical 0 3 78 9 2 0 1 2 5 0 0 07/10/2012 Typical 0 2 83 11 2 1 1 0 0 0 0 08/07/2012 Typical 0 2 81 16 1 0 0 0 0 0 0 09/05/2012 Typical 0 1 65 21 5 4 2 2 0 0 0 09/25/2012 Typical 0 2 53 15 7 4 3 4 12 0 0 10/16/2012 Typical 0 2 63 14 2 2 3 8 6 0 0 10/30/2012 Typical 0 2 73 11 1 2 2 5 4 0 0 11/06/2012 Typical 0 1 69 18 3 2 2 4 1 0 0 

Missouri River near Maskell, Nebraska (Maskell site)

06/23/2011 High 0 0 19 74 7 0 0 0 0 0 0 

06/30/2011 High 0 1 32 58 8 1 0 0 0 0 0 07/21/2011 High 0 2 36 44 16 2 0 0 0 0 0 08/04/2011 High 0 1 24 45 22 6 2 0 0 0 0 08/18/2011 High 0 1 36 54 6 1 1 1 0 0 0 09/01/2011 High 0 0 17 50 22 4 1 1 5 0 0 09/15/2011 High 0 0 22 54 20 2 1 1 0 0 0 11/02/2011 Typical 0 0 12 64 21 2 0 0 1 0 0 05/31/2012 Typical 0 1 29 41 26 2 1 0 0 0 0 06/20/2012 Typical 0 2 20 48 23 4 1 0 2 0 0 07/09/2012 Typical 0 1 15 57 23 3 1 0 0 0 0 08/09/2012 Typical 0 3 20 45 19 8 3 2 0 0 0 09/06/2012 Typical 0 0 10 48 26 8 4 2 2 0 0 10/11/2012 Typical 0 1 5 49 37 5 2 1 0 0 0 11/15/2012 Typical 2 4 13 60 18 2 1 0 0 0 0 

Table 1–3. Grain sizes of bed-material samples for six Missouri River sites, 2011–12.—Continued[mm, millimeter; D65, grain-size diameter at which 65 percent of the mass is finer; --, not available]
Date Stream- flow conditions Bed-material fall diameter (grain size) (percent in size range, by weight) 

Less than 0.062 mm 0.062 to 0.125 mm 0.125 to 0.250 mm 0.250 to 0.500 mm 0.500 to 1 mm 1 to 2 mm 2 to 4 mm 4 to 8 mm 8 to 16 mm 16 to 32 mm 32 t

63 m

Missouri River at Sioux City, Iowa (Sioux City site) 07/01/2011 High 1 0 47 36 16 0 0 0 0 0 0 

08/05/2011 High 0 0 34 37 19 7 1 1 1 0 0 08/19/2011 High 0 1 31 35 6 5 6 9 5 2 0 09/02/2011 High 0 1 31 42 16 3 1 1 0 5 0 09/16/2011 High 0 1 31 64 2 1 1 0 0 0 0 11/01/2011 Typical 0 0 14 74 9 2 1 0 0 0 0 06/01/2012 Typical 0 0 3 34 13 1 0 1 1 0 0 06/19/2012 Typical 0 0 5 40 16 2 0 1 3 33 0 07/10/2012 Typical 0 1 27 61 10 1 0 0 0 0 0 08/10/2012 Typical 0 0 8 40 23 8 0 2 7 12 0 09/07/2012 Typical 0 0 10 71 16 2 0 1 0 0 0 10/12/2012 Typical 0 0 14 76 9 1 0 0 0 0 0 11/16/2012 Typical 0 0 9 70 17 4 0 0 0 0 0 

Missouri River at Omaha, Nebraska (Omaha site) 07/08/2011 High 1 3 16 56 18 3 1 2 0 0 0 

07/18/2011 High -- -- -- -- -- -- -- -- -- -- -- 08/01/2011 High 0 0 5 56 30 7 2 0 0 0 0 08/15/2011 High 0 0 7 63 27 3 0 0 0 0 0 08/29/2011 High -- -- -- -- -- -- -- -- -- -- -- 09/12/2011 High 0 0 22 70 7 1 0 0 0 0 0 10/31/2011 Typical 0 0 9 58 15 5 4 2 7 0 0 

Missouri River at Nebraska City, Nebraska (Nebraska City site)

06/21/2011 High -- -- -- -- -- -- -- -- -- -- -- 06/27/2011 High 0 0 3 37 52 4 1 2 1 0 0 07/19/2011 High 0 0 4 24 33 20 13 6 0 0 0 08/02/2011 High 0 0 9 31 31 17 7 3 2 0 0 08/16/2011 High 0 1 17 30 33 12 5 2 0 0 0 08/30/2011 High -- -- -- -- -- -- -- -- -- -- -- 09/13/2011 High 0 3 51 26 13 4 2 1 0 0 0 11/03/2011 Typical 9 5 44 40 2 0 0 0 0 0 0 

Table 1–3. Grain sizes of bed-material samples for six Missouri River sites, 2011–12.—Continued[mm, millimeter; D65, grain-size diameter at which 65 percent of the mass is finer; --, not available]
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Rus and others—Characteristics of Sediment Transport at Selected Sites Along the Missouri River, 2011–12—SIR 2015–5127

ISSN 2328-0328 (online)

http://dx.doi.org/10.3133/sir20155127