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Powder River: Data for Cross-Channel Profiles at 22 Sites in Southeastern Montana, 1975 through 2019

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By Water Resources Mission Area August 30, 2020

Powder River rises in the Bighorn Mountains of Wyoming and flows northward through a semi-arid landscape in Wyoming and Montana to the Yellowstone River. The river drains an area of 34,700 square kilometers and has an average discharge of about 500 million cubic meters per year. Cross-channel profile data were collected at 22 sites on the river and its tributaries from 1975 through 2014.

 

Introduction

Photo of the Powder River in southeastern Montana, with mountains in the background.
Sources/Usage: Public Domain. View Media Details
This view of the river looking northward, and hence downstream, was taken in October 2012, about 20 kilometers (km) north of the Wyoming-Montana state line, about 4 km downstream from an operating gaging station at Moorhead, Montana (USGS station number 06324500), and about 80 river km upstream from a discontinued gaging station at Broadus, Montana (USGS station number 06324710). The river is emerging from a narrowly-confined reach, and the valley widens northward, bordered by hills of the coal-bearing Fort Union Formation.

Powder River rises in the Bighorn Mountains of Wyoming and flows northward through a semi-arid landscape in Wyoming and Montana to the Yellowstone River. The river drains an area of 34,700 square kilometers and has an average discharge of about 500 million cubic meters per year (or 16 cubic meters per second).

The river in the adjacent photo is at about bed-full flow (12 m3 s-1, Moody and others, 1999), and several riffles with disturbed water can be seen downstream between smooth glassy reaches of the river. A narrow band (~2-4 m wide) of reddish sedge (Scirpus spp.) grows just above the bed-full level along the edge of water with a wider band of mixed grasses (Agropyron repens, A. pauciflorum, Bromus inermis, Elymus canadenis, Spartina pectinata, and S. cynosoroids), willow (Salix exigua), tamarisk (Tamirix ramosissima) and small cottonwood seedlings and trees (Populus sargentii) on the flood plain. Three terrace levels have been identified along the river (Leopold and Miller, 1954; Moody and Meade, 2008). The first is the Lightning Terrace with small cottonwood trees (seen here without leaves) adjacent to the floodplain in the right-center of the photo. The second is the Moorcroft Terrace seen best forming the left bank and extending as a flat surface to the left (west) with a few large cottonwood trees still retaining their green leaves. The third is the colluvial Kaycee Terrace that grades slowly upwards and meets the hills of the Fort Union Formation. It can be seen on the right side at the base of the hills and in the far distance on the left side, west of the white ranch buildings.

Powder River has no dams or other large-scale human modifications, which, combined with its substantial suspended-sediment load (2-3 million metric tons per year), makes it an optimal outdoor laboratory for studying natural fluvial processes (Moody and Meade, 1990; Hubert, 1993; Moody and others 2002). A research program was started in 1975 and, by 1977, 20 channel cross sections had been established in the 93-km reach, with the uppermost (PR113) just upstream from the Moorhead gage and the lowermost (PR206, see map) just downstream from the Broadus gage. Cross section PR120 crosses the river in the above photo at a point near where the shadows from the large cottonwood trees on the left bank meet the river downstream from the apex of the nearer bend (Moody and others 1999; Pizzuto and others, 2008). An extreme flood in 1978 (779 m3 s-1) (Moody and Meade, 2008; Meade and Moody, 2013) was a major disturbance that widened the channel, caused two meander cutoffs (not visible in this photo), and deposited fresh sediment on the Lightning and Moorcroft terraces. Two additional cross sections (PR 122A and PR141A) were established on the cutoffs in 1979, and the post-flood response has been monitored at most channel cross sections through 2012. Elevation datum is NGVD29, and all cross-sectional data (1975-1998) also are available in the Results tab of this page.

Map showing channel cross section locations for Powder River study area.
Sources/Usage: Public Domain. View Media Details
Map showing locations of 20 channel cross sections and the tributaries of Powder River in the study reach. The dashed line indicates the approximate boundary of the visually-obvious valley. Longitude and latitude tick marks are on the outside of the border, and tick marks for the universal transverse mercator (UTM) gride are on the inside of the border. DA and DV are the identification letters for the 100,000-meter-square grid. "Forty-fifth parallel" (45o 00' N) is the Montana-Wyoming state line. "PR113" is the cross section identification.

 

Current Discharge Data 

 

Citation For This Dataset

Moody, J.A., and Meade, R.H., 2014, Powder River: Data for cross-channel profiles at 22 sites in southeastern Montana from 1975 through 2014, Washington: U.S. Geological Survey Data Set, doi:10.5066/F70Z719C.

 

General Data

 

Cross Section Information

Download cross-section data from our data release page for the cross sections discussed below (link opens in a new tab).

 

Cross Section PR113

Download narrative and photos for cross section PR113

Powder River Data: Cross Section 113, 2013A Powder River Data: Cross Section 113, 2013B

 

Cross Section PR116

Download narrative and photos for cross section PR116

Powder River Data: Cross Section 116, 2013A Powder River Data: Cross Section 116, 2013B

 

Cross Section PR120 

Download narrative and photos for cross section PR120

Powder River Data: Cross Section 120, 2013A Powder River Data: Cross Section 120, 2013B

 

Cross Section PR122

Download narrative and photos for cross section PR122

Powder River Data: Cross Section 122, 2013A Powder River Data: Cross Section 122, 2013B

 

Cross Section PR122A

Download narrative and photos for cross section PR122A

Powder River Data: Cross Section 122A, 2013A Powder River Data: Cross Section 122A, 2013B

 

Cross Section PR125

Download narrative and photos for cross section PR125

Powder River Data: Cross Section 125, 2013A Powder River Data: Cross Section 125, 2013B

 

Cross Section PR130

Download narrative and photos for cross section PR130

Powder River Data: Cross Section 130, 2013A Powder River Data: Cross Section 130, 2013B

 

Cross Section PR136

Download narrative and photos for cross section PR136

Powder River Data: Cross Section 136, 2013A Powder River Data: Cross Section 136, 2013B

 

Cross Section PR141

Download narrative and photos for cross section PR141

Powder River Data: Cross Section 141, 2013A Powder River Data: Cross Section 141, 2013B

 

Cross Section PR141A

Download narrative and photos for cross section PR141A

Powder River Data: Cross Section 141A, 2013A Powder River Data: Cross Section 141A, 2013B

 

Cross Section PR141P7

Download narrative and photos for cross section PR141P7

Powder River Data: Cross Section 141P7, 2013A Powder River Data: Cross Section 141P7, 2013B

 

Cross Section PR147

Download narrative and photos for cross section PR147 

Powder River Data: Cross Section 147, 2013A Powder River Data: Cross Section 147, 2013B

 

Cross Section PR151 

Download narrative and photos for cross section PR151

Powder River Data: Cross Section 151, 2013A Powder River Data: Cross Section 151, 2013B

 

Cross Section PR156 

Download narrative and photos for cross section PR156

Powder River Data: Cross Section 156, 2013A Powder River Data: Cross Section 156, 2013B

 

Cross Section PR156A

Download narrative and photos for cross section PR156A

Powder River Data: Cross Section 156A, 2013A Powder River Data: Cross Section 156A, 2013B

 

Cross Section PR163 

Download narrative and photos for cross section PR163

Powder River Data: Cross Section 163, 2013A Powder River Data: Cross Section 163, 2013B

 

Cross Section PR167 

Download narrative and photos for cross section PR167

Powder River Data: Cross Section 167, 2013A Powder River Data: Cross Section 167, 2013B

 

Cross Section PR180 

Download narrative and photos for cross section PR180

Powder River Data: Cross Section 180, 2011A Powder River Data: Cross Section 180, 2011B

 

Cross Section PR183 

Download narrative and photos for cross section PR183

Powder River Data: Cross Section 183, 2011A Powder River Data: Cross Section 183, 2011B

 

Cross Section PR191 

Download narrative and photos for cross section PR191

Powder River Data: Cross Section 191, 2011A Powder River Data: Cross Section 191, 2011B

 

Cross Section PR194

Download narrative and photos for cross section PR194

Powder River Data: Cross Section 194, 2011A Powder River Data: Cross Section 194, 2011B

 

Cross Section PR206 

Download narrative and photos for cross section PR206

Powder River Data: Cross Section 206, 2011A Powder River Data: Cross Section 206, 2011B

Below are data or web applications associated with this project.

Channel Cross-section Data for Powder River between Moorhead and Broadus, Montana from 1975 to 2016

This data release consist of 34 channel cross sections of Powder River measured from 1975 through 2016 along a 90-kilometer reach from Moorhead to Broadus, Montana. Most channel cross sections were measured annually from 1975 through 1998 and then intermittently through 2016. In 1978, after all cross sections had been established, there was a extreme flood with an approximate 50-year...
By
Water Resources Mission Area

Below are publications associated with the Powder River Study Area.

Filter Total Items: 19

Decadal changes in channel morphology of a freely meandering river—Powder River, Montana, 1975–2016

Few studies exist on the long-term geomorphic effects of floods. However, the U.S. Geological Survey (USGS) was able to begin such a study after a 50-year recurrence interval flood in 1978 because 20 channel cross sections along a 100-kilometer reach of river were established in 1975 and 1977 as part of a study for a proposed dam on Powder River in southeastern Montana. These cross...
Authors
John A. Moody, Robert H. Meade

A 184-year record of river meander migration from tree rings, aerial imagery, and cross sections

Channel migration is the primary mechanism of floodplain turnover in meandering rivers and is essential to the persistence of riparian ecosystems. Channel migration is driven by river flows, but short-term records cannot disentangle the effects of land use, flow diversion, past floods, and climate change. We used three data sets to quantify nearly two centuries of channel migration on...
Authors
Derek M. Schook, Sara L. Rathburn, Jonathan M. Friedman, J. Marshall Wolf
By
Ecosystems Mission Area, Fort Collins Science Center

Flow reconstructions in the Upper Missouri River Basin using riparian tree rings

River flow reconstructions are typically developed using tree rings from montane conifers that cannot reflect flow regulation or hydrologic inputs from the lower portions of a watershed. Incorporating lowland riparian trees may improve the accuracy of flow reconstructions when these trees are physically linked to the alluvial water table. We used riparian plains cottonwoods (Populus...
Authors
Derek M. Schook, Jonathan M. Friedman, Sara L. Rathburn
By
Ecosystems Mission Area, Fort Collins Science Center

Preserving geomorphic data records of flood disturbances

No central database or repository is currently available in the USA to preserve long-term, spatially extensive records of fluvial geomorphic data or to provide future accessibility. Yet, because of their length and continuity these data are valuable for future research. Therefore, we built a public accessible website to preserve data records of two examples of long-term monitoring (40...
Authors
John A. Moody, Deborah A. Martin, Robert H. Meade

Erosional and depositional changes wrought by the flood of May 1978 in the channels of Powder River, southeastern Montana

Powder River’s second largest flood of record (1919–2012) moved through northeastern Wyoming and southeastern Montana during May 1978. Within a ninety-kilometer reach of the channel in southeastern Montana, the most prominent planform effects of the flood were the growth of meander bends by bank erosion (this was most intense just downriver of bend apexes, causing 1–2 channel widths of...
Authors
Robert H. Meade, John A. Moody
By
Water Resources Mission Area

Anatomy and dynamics of a floodplain, Powder River, Montana, U.S.A.

Centimeter-scale measurements on several Powder River floodplains provide insights into the nature of overbank depositional processes that created the floodplains; during a 20-year period after a major flood in 1978. Rising stages initially entered across a sill at the downriver end of the floodplains. Later, as stages continued to rise, water entered the floodplains through distinct low...
Authors
J.E. Pizzuto, J. A. Moody, R.H. Meade

Terrace aggradation during the 1978 flood on Powder River, Montana, USA

Flood processes no longer actively increase the planform area of terraces. Instead, lateral erosion decreases the area. However, infrequent extreme floods continue episodic aggradation of terraces surfaces. We quantify this type of evolution of terraces by an extreme flood in May 1978 on Powder River in southeastern Montana. Within an 89-km study reach of the river, we (1) determine a...
Authors
J. A. Moody, R.H. Meade

Characterization of the spatial variability of channel morphology

The spatial variability of two fundamental morphological variables is investigated for rivers having a wide range of discharge (five orders of magnitude). The variables, water-surface width and average depth, were measured at 58 to 888 equally spaced cross-sections in channel links (river reaches between major tributaries). These measurements provide data to characterize the two...
Authors
J. A. Moody, B.M. Troutman

Field Measurements of Reynolds Stress near a Riverbank

The Reynolds stress field was measured near the bank of the Powder River in southeastern Montana. The measurements were made from the bank using an aluminum I-beam cantilevered over the water to support a carriage system for positioning an acoustic doppler velocimeter in a vertical plane perpendicular to 1) the bank and 2) the streamwise velocity field. During quasi-steady flow at the...
Authors
J. A. Moody, J.D. Smith

Erosion and deposition of sediment at channel cross sections on powder river between Moorhead and Broadus, Montana, 1980-98

No abstract available.
Authors
John A. Moody, Robert H. Meade, Holly A. Martinson

Quantitative model of the growth of floodplains by vertical accretion

A simple one-dimensional model is developed to quantitatively predict the change in elevation, over a period of decades, for vertically accreting floodplains. This unsteady model approximates the monotonic growth of a floodplain as an incremental but constant increase of net sediment deposition per flood for those floods of a partial duration series that exceed a threshold discharge...
Authors
J. A. Moody, B.M. Troutman

Ontogeny of a flood plain

The ontogeny of five flood-plain segments is described for a period of 18 yr following a major flood in 1978 on the Powder River in southeastern Montana. The flood plains developed on relatively elevated sand and gravel deposits left within the channel by the 1978 flood. In cross section, the flood plains resemble benches with well-developed natural levees. Flood-plain growth occurred as...
Authors
J. A. Moody, J.E. Pizzuto, R.H. Meade

Powder River rises in the Bighorn Mountains of Wyoming and flows northward through a semi-arid landscape in Wyoming and Montana to the Yellowstone River. The river drains an area of 34,700 square kilometers and has an average discharge of about 500 million cubic meters per year. Cross-channel profile data were collected at 22 sites on the river and its tributaries from 1975 through 2014.

 

Introduction

Photo of the Powder River in southeastern Montana, with mountains in the background.
Sources/Usage: Public Domain. View Media Details
This view of the river looking northward, and hence downstream, was taken in October 2012, about 20 kilometers (km) north of the Wyoming-Montana state line, about 4 km downstream from an operating gaging station at Moorhead, Montana (USGS station number 06324500), and about 80 river km upstream from a discontinued gaging station at Broadus, Montana (USGS station number 06324710). The river is emerging from a narrowly-confined reach, and the valley widens northward, bordered by hills of the coal-bearing Fort Union Formation.

Powder River rises in the Bighorn Mountains of Wyoming and flows northward through a semi-arid landscape in Wyoming and Montana to the Yellowstone River. The river drains an area of 34,700 square kilometers and has an average discharge of about 500 million cubic meters per year (or 16 cubic meters per second).

The river in the adjacent photo is at about bed-full flow (12 m3 s-1, Moody and others, 1999), and several riffles with disturbed water can be seen downstream between smooth glassy reaches of the river. A narrow band (~2-4 m wide) of reddish sedge (Scirpus spp.) grows just above the bed-full level along the edge of water with a wider band of mixed grasses (Agropyron repens, A. pauciflorum, Bromus inermis, Elymus canadenis, Spartina pectinata, and S. cynosoroids), willow (Salix exigua), tamarisk (Tamirix ramosissima) and small cottonwood seedlings and trees (Populus sargentii) on the flood plain. Three terrace levels have been identified along the river (Leopold and Miller, 1954; Moody and Meade, 2008). The first is the Lightning Terrace with small cottonwood trees (seen here without leaves) adjacent to the floodplain in the right-center of the photo. The second is the Moorcroft Terrace seen best forming the left bank and extending as a flat surface to the left (west) with a few large cottonwood trees still retaining their green leaves. The third is the colluvial Kaycee Terrace that grades slowly upwards and meets the hills of the Fort Union Formation. It can be seen on the right side at the base of the hills and in the far distance on the left side, west of the white ranch buildings.

Powder River has no dams or other large-scale human modifications, which, combined with its substantial suspended-sediment load (2-3 million metric tons per year), makes it an optimal outdoor laboratory for studying natural fluvial processes (Moody and Meade, 1990; Hubert, 1993; Moody and others 2002). A research program was started in 1975 and, by 1977, 20 channel cross sections had been established in the 93-km reach, with the uppermost (PR113) just upstream from the Moorhead gage and the lowermost (PR206, see map) just downstream from the Broadus gage. Cross section PR120 crosses the river in the above photo at a point near where the shadows from the large cottonwood trees on the left bank meet the river downstream from the apex of the nearer bend (Moody and others 1999; Pizzuto and others, 2008). An extreme flood in 1978 (779 m3 s-1) (Moody and Meade, 2008; Meade and Moody, 2013) was a major disturbance that widened the channel, caused two meander cutoffs (not visible in this photo), and deposited fresh sediment on the Lightning and Moorcroft terraces. Two additional cross sections (PR 122A and PR141A) were established on the cutoffs in 1979, and the post-flood response has been monitored at most channel cross sections through 2012. Elevation datum is NGVD29, and all cross-sectional data (1975-1998) also are available in the Results tab of this page.

Map showing channel cross section locations for Powder River study area.
Sources/Usage: Public Domain. View Media Details
Map showing locations of 20 channel cross sections and the tributaries of Powder River in the study reach. The dashed line indicates the approximate boundary of the visually-obvious valley. Longitude and latitude tick marks are on the outside of the border, and tick marks for the universal transverse mercator (UTM) gride are on the inside of the border. DA and DV are the identification letters for the 100,000-meter-square grid. "Forty-fifth parallel" (45o 00' N) is the Montana-Wyoming state line. "PR113" is the cross section identification.

 

Current Discharge Data 

 

Citation For This Dataset

Moody, J.A., and Meade, R.H., 2014, Powder River: Data for cross-channel profiles at 22 sites in southeastern Montana from 1975 through 2014, Washington: U.S. Geological Survey Data Set, doi:10.5066/F70Z719C.

 

General Data

 

Cross Section Information

Download cross-section data from our data release page for the cross sections discussed below (link opens in a new tab).

 

Cross Section PR113

Download narrative and photos for cross section PR113

Powder River Data: Cross Section 113, 2013A Powder River Data: Cross Section 113, 2013B

 

Cross Section PR116

Download narrative and photos for cross section PR116

Powder River Data: Cross Section 116, 2013A Powder River Data: Cross Section 116, 2013B

 

Cross Section PR120 

Download narrative and photos for cross section PR120

Powder River Data: Cross Section 120, 2013A Powder River Data: Cross Section 120, 2013B

 

Cross Section PR122

Download narrative and photos for cross section PR122

Powder River Data: Cross Section 122, 2013A Powder River Data: Cross Section 122, 2013B

 

Cross Section PR122A

Download narrative and photos for cross section PR122A

Powder River Data: Cross Section 122A, 2013A Powder River Data: Cross Section 122A, 2013B

 

Cross Section PR125

Download narrative and photos for cross section PR125

Powder River Data: Cross Section 125, 2013A Powder River Data: Cross Section 125, 2013B

 

Cross Section PR130

Download narrative and photos for cross section PR130

Powder River Data: Cross Section 130, 2013A Powder River Data: Cross Section 130, 2013B

 

Cross Section PR136

Download narrative and photos for cross section PR136

Powder River Data: Cross Section 136, 2013A Powder River Data: Cross Section 136, 2013B

 

Cross Section PR141

Download narrative and photos for cross section PR141

Powder River Data: Cross Section 141, 2013A Powder River Data: Cross Section 141, 2013B

 

Cross Section PR141A

Download narrative and photos for cross section PR141A

Powder River Data: Cross Section 141A, 2013A Powder River Data: Cross Section 141A, 2013B

 

Cross Section PR141P7

Download narrative and photos for cross section PR141P7

Powder River Data: Cross Section 141P7, 2013A Powder River Data: Cross Section 141P7, 2013B

 

Cross Section PR147

Download narrative and photos for cross section PR147 

Powder River Data: Cross Section 147, 2013A Powder River Data: Cross Section 147, 2013B

 

Cross Section PR151 

Download narrative and photos for cross section PR151

Powder River Data: Cross Section 151, 2013A Powder River Data: Cross Section 151, 2013B

 

Cross Section PR156 

Download narrative and photos for cross section PR156

Powder River Data: Cross Section 156, 2013A Powder River Data: Cross Section 156, 2013B

 

Cross Section PR156A

Download narrative and photos for cross section PR156A

Powder River Data: Cross Section 156A, 2013A Powder River Data: Cross Section 156A, 2013B

 

Cross Section PR163 

Download narrative and photos for cross section PR163

Powder River Data: Cross Section 163, 2013A Powder River Data: Cross Section 163, 2013B

 

Cross Section PR167 

Download narrative and photos for cross section PR167

Powder River Data: Cross Section 167, 2013A Powder River Data: Cross Section 167, 2013B

 

Cross Section PR180 

Download narrative and photos for cross section PR180

Powder River Data: Cross Section 180, 2011A Powder River Data: Cross Section 180, 2011B

 

Cross Section PR183 

Download narrative and photos for cross section PR183

Powder River Data: Cross Section 183, 2011A Powder River Data: Cross Section 183, 2011B

 

Cross Section PR191 

Download narrative and photos for cross section PR191

Powder River Data: Cross Section 191, 2011A Powder River Data: Cross Section 191, 2011B

 

Cross Section PR194

Download narrative and photos for cross section PR194

Powder River Data: Cross Section 194, 2011A Powder River Data: Cross Section 194, 2011B

 

Cross Section PR206 

Download narrative and photos for cross section PR206

Powder River Data: Cross Section 206, 2011A Powder River Data: Cross Section 206, 2011B

Below are data or web applications associated with this project.

Channel Cross-section Data for Powder River between Moorhead and Broadus, Montana from 1975 to 2016

This data release consist of 34 channel cross sections of Powder River measured from 1975 through 2016 along a 90-kilometer reach from Moorhead to Broadus, Montana. Most channel cross sections were measured annually from 1975 through 1998 and then intermittently through 2016. In 1978, after all cross sections had been established, there was a extreme flood with an approximate 50-year...
By
Water Resources Mission Area

Below are publications associated with the Powder River Study Area.

Filter Total Items: 19

Decadal changes in channel morphology of a freely meandering river—Powder River, Montana, 1975–2016

Few studies exist on the long-term geomorphic effects of floods. However, the U.S. Geological Survey (USGS) was able to begin such a study after a 50-year recurrence interval flood in 1978 because 20 channel cross sections along a 100-kilometer reach of river were established in 1975 and 1977 as part of a study for a proposed dam on Powder River in southeastern Montana. These cross...
Authors
John A. Moody, Robert H. Meade

A 184-year record of river meander migration from tree rings, aerial imagery, and cross sections

Channel migration is the primary mechanism of floodplain turnover in meandering rivers and is essential to the persistence of riparian ecosystems. Channel migration is driven by river flows, but short-term records cannot disentangle the effects of land use, flow diversion, past floods, and climate change. We used three data sets to quantify nearly two centuries of channel migration on...
Authors
Derek M. Schook, Sara L. Rathburn, Jonathan M. Friedman, J. Marshall Wolf
By
Ecosystems Mission Area, Fort Collins Science Center

Flow reconstructions in the Upper Missouri River Basin using riparian tree rings

River flow reconstructions are typically developed using tree rings from montane conifers that cannot reflect flow regulation or hydrologic inputs from the lower portions of a watershed. Incorporating lowland riparian trees may improve the accuracy of flow reconstructions when these trees are physically linked to the alluvial water table. We used riparian plains cottonwoods (Populus...
Authors
Derek M. Schook, Jonathan M. Friedman, Sara L. Rathburn
By
Ecosystems Mission Area, Fort Collins Science Center

Preserving geomorphic data records of flood disturbances

No central database or repository is currently available in the USA to preserve long-term, spatially extensive records of fluvial geomorphic data or to provide future accessibility. Yet, because of their length and continuity these data are valuable for future research. Therefore, we built a public accessible website to preserve data records of two examples of long-term monitoring (40...
Authors
John A. Moody, Deborah A. Martin, Robert H. Meade

Erosional and depositional changes wrought by the flood of May 1978 in the channels of Powder River, southeastern Montana

Powder River’s second largest flood of record (1919–2012) moved through northeastern Wyoming and southeastern Montana during May 1978. Within a ninety-kilometer reach of the channel in southeastern Montana, the most prominent planform effects of the flood were the growth of meander bends by bank erosion (this was most intense just downriver of bend apexes, causing 1–2 channel widths of...
Authors
Robert H. Meade, John A. Moody
By
Water Resources Mission Area

Anatomy and dynamics of a floodplain, Powder River, Montana, U.S.A.

Centimeter-scale measurements on several Powder River floodplains provide insights into the nature of overbank depositional processes that created the floodplains; during a 20-year period after a major flood in 1978. Rising stages initially entered across a sill at the downriver end of the floodplains. Later, as stages continued to rise, water entered the floodplains through distinct low...
Authors
J.E. Pizzuto, J. A. Moody, R.H. Meade

Terrace aggradation during the 1978 flood on Powder River, Montana, USA

Flood processes no longer actively increase the planform area of terraces. Instead, lateral erosion decreases the area. However, infrequent extreme floods continue episodic aggradation of terraces surfaces. We quantify this type of evolution of terraces by an extreme flood in May 1978 on Powder River in southeastern Montana. Within an 89-km study reach of the river, we (1) determine a...
Authors
J. A. Moody, R.H. Meade

Characterization of the spatial variability of channel morphology

The spatial variability of two fundamental morphological variables is investigated for rivers having a wide range of discharge (five orders of magnitude). The variables, water-surface width and average depth, were measured at 58 to 888 equally spaced cross-sections in channel links (river reaches between major tributaries). These measurements provide data to characterize the two...
Authors
J. A. Moody, B.M. Troutman

Field Measurements of Reynolds Stress near a Riverbank

The Reynolds stress field was measured near the bank of the Powder River in southeastern Montana. The measurements were made from the bank using an aluminum I-beam cantilevered over the water to support a carriage system for positioning an acoustic doppler velocimeter in a vertical plane perpendicular to 1) the bank and 2) the streamwise velocity field. During quasi-steady flow at the...
Authors
J. A. Moody, J.D. Smith

Erosion and deposition of sediment at channel cross sections on powder river between Moorhead and Broadus, Montana, 1980-98

No abstract available.
Authors
John A. Moody, Robert H. Meade, Holly A. Martinson

Quantitative model of the growth of floodplains by vertical accretion

A simple one-dimensional model is developed to quantitatively predict the change in elevation, over a period of decades, for vertically accreting floodplains. This unsteady model approximates the monotonic growth of a floodplain as an incremental but constant increase of net sediment deposition per flood for those floods of a partial duration series that exceed a threshold discharge...
Authors
J. A. Moody, B.M. Troutman

Ontogeny of a flood plain

The ontogeny of five flood-plain segments is described for a period of 18 yr following a major flood in 1978 on the Powder River in southeastern Montana. The flood plains developed on relatively elevated sand and gravel deposits left within the channel by the 1978 flood. In cross section, the flood plains resemble benches with well-developed natural levees. Flood-plain growth occurred as...
Authors
J. A. Moody, J.E. Pizzuto, R.H. Meade
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