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Steve Holnbeck (Former Employee)

Science and Products

Measuring bridge scour on Clark Fork River near Superior, MT

Bridge Scour in Montana

Bridge scour is the erosion of streambed material away from pier foundations and abutments and is the leading cause of bridge failure in the United States (Richardson and Davis, 2001). Since the early 1990s, the U.S. Geological Survey (USGS) and the Montana Department of Transportation (MDT) have had a cooperative bridge scour project in Montana.
By
Wyoming-Montana Water Science Center
Bridge Scour in Montana

Bridge Scour in Montana

Bridge scour is the erosion of streambed material away from pier foundations and abutments and is the leading cause of bridge failure in the United States (Richardson and Davis, 2001). Since the early 1990s, the U.S. Geological Survey (USGS) and the Montana Department of Transportation (MDT) have had a cooperative bridge scour project in Montana.
Learn More

Channel geometry for upstream and downstream cross sections at selected bridge sites in Montana, 2022 Channel geometry for upstream and downstream cross sections at selected bridge sites in Montana, 2022

The U.S. Geological Survey, in cooperation with the Montana Department of Transportation (MDT), collected cross-section data on the upstream and downstream sides at 18 sites involving 20 bridges in Montana during the 2022 calendar year. The purpose of the data collection is to determine if scour and channel instability occur in the vicinity of the bridge structures. Data were processed...
By
Wyoming-Montana Water Science Center

Channel geometry for upstream and downstream cross sections at selected bridge sites in Montana, 2021 Channel geometry for upstream and downstream cross sections at selected bridge sites in Montana, 2021

The U.S. Geological Survey, in cooperation with the Montana Department of Transportation (MDT), collected cross-section data on the upstream and downstream sides at selected bridges in Montana during the 2021 calendar year. The purpose of the data collection is to determine if scour and channel instability occur in the vicinity of the bridge structures. Data were processed, analyzed, and...
By
Wyoming-Montana Water Science Center

Channel geometry for upstream and downstream cross sections at selected bridge sites in Montana, 2020 Channel geometry for upstream and downstream cross sections at selected bridge sites in Montana, 2020

The U.S. Geological Survey, in cooperation with the Montana Department of Transportation (MDT), collected cross-section data on the upstream and downstream sides at selected bridges in Montana during the 2020 calendar year. The purpose of the data collection is to determine if scour and channel instability occur in the vicinity of the bridge structures. Data were processed, analyzed, and...
By
Wyoming-Montana Water Science Center

Water-surface elevation data and flood and floodway boundaries for the upper Yellowstone River, Montana Water-surface elevation data and flood and floodway boundaries for the upper Yellowstone River, Montana

No abstract available.
By
Yellowstone
Surveying water surface along with other methods to describe scour
Surveying water surface along with other methods to describe scour
Surveying water surface along with other methods to describe scour
Surveying water surface along with other methods to describe scour

Surveying water surface along with other methods to describe scour

Surveying water surface along with other methods to describe scour

Surveying water surface to tie into bathymetry measurments on Bitterroot River near Hamilton, MT to describe scour near the bridge.

By
Wyoming-Montana Water Science Center
Surveying water surface along with other methods to describe scour

Surveying water surface along with other methods to describe scour

Surveying water surface along with other methods to describe scour

Surveying water surface to tie into bathymetry measurments on Bitterroot River near Hamilton, MT to describe scour near the bridge.

By
Wyoming-Montana Water Science Center
Ground point survey with robotic total station and prism and rod techniques, measuring depth of streambed to assess b
Ground point survey with total station to measure depth to streambed
Ground point survey with total station to measure depth to streambed
Ground point survey with robotic total station and prism and rod techniques, measuring depth of streambed to assess b

Ground point survey with total station to measure depth to streambed

Ground point survey with total station to measure depth to streambed

Ground point survey with Trimble S6 robotic total station and prism and rod techniques, measuring depth of streambed to assess bridge scour on West Gallatin River near Belgrade, MT

By
Wyoming-Montana Water Science Center
Ground point survey with robotic total station and prism and rod techniques, measuring depth of streambed to assess b

Ground point survey with total station to measure depth to streambed

Ground point survey with total station to measure depth to streambed

Ground point survey with Trimble S6 robotic total station and prism and rod techniques, measuring depth of streambed to assess bridge scour on West Gallatin River near Belgrade, MT

By
Wyoming-Montana Water Science Center
Bathymetry survey measuring streambed depths along pier
Bathymetry survey measuring streambed depths along bridge pi
Bathymetry survey measuring streambed depths along bridge pi
Bathymetry survey measuring streambed depths along pier

Bathymetry survey measuring streambed depths along bridge pi

Bathymetry survey measuring streambed depths along bridge pi

Bathymetry survey with Trimble S6 robotic total station, hydrolite single-beam echosounder transducer, and HYPACK software, measuring streambed depths along bridge pier on Beaverhead River in Twin Bridges, MT

By
Wyoming-Montana Water Science Center
Bathymetry survey measuring streambed depths along pier

Bathymetry survey measuring streambed depths along bridge pi

Bathymetry survey measuring streambed depths along bridge pi

Bathymetry survey with Trimble S6 robotic total station, hydrolite single-beam echosounder transducer, and HYPACK software, measuring streambed depths along bridge pier on Beaverhead River in Twin Bridges, MT

By
Wyoming-Montana Water Science Center
Measuring bridge scour on Clark Fork River near Superior, MT
Measuring bridge scour on Clark Fork River near Superior, MT
Measuring bridge scour on Clark Fork River near Superior, MT
Measuring bridge scour on Clark Fork River near Superior, MT

Measuring bridge scour on Clark Fork River near Superior, MT

Measuring bridge scour on Clark Fork River near Superior, MT

Measuring bridge scour on Clark Fork River near Superior, MT (April 4, 2007)

By
Wyoming-Montana Water Science Center
Measuring bridge scour on Clark Fork River near Superior, MT

Measuring bridge scour on Clark Fork River near Superior, MT

Measuring bridge scour on Clark Fork River near Superior, MT

Measuring bridge scour on Clark Fork River near Superior, MT (April 4, 2007)

By
Wyoming-Montana Water Science Center

Evaluating the use of video cameras to estimate bridge scour potential at four bridges in southwestern Montana Evaluating the use of video cameras to estimate bridge scour potential at four bridges in southwestern Montana

The U.S. Geological Survey, in cooperation with the Montana Department of Transportation, installed cameras and large-scale particle image velocimetry (LSPIV) recording equipment at four sites where the U.S. Geological Survey and Montana Department of Transportation are monitoring bridge scour using other methods. Determination of stream velocities is an important component of hydraulic...
Authors
Daniel Armstrong, Stephen Holnbeck, Katherine Chase
By
Water Resources Mission Area, Wyoming-Montana Water Science Center

Near-field remote sensing of surface velocity and river discharge using radars and the probability concept at 10 USGS streamgages Near-field remote sensing of surface velocity and river discharge using radars and the probability concept at 10 USGS streamgages

Near-field remote sensing of surface velocity and river discharge (discharge) were measured using coherent, continuous wave Doppler and pulsed radars. Traditional streamgaging requires sensors be deployed in the water column; however, near-field remote sensing has the potential to transform streamgaging operations through non-contact methods in the U.S. Geological Survey (USGS) and other...
Authors
John Fulton, Christopher Mason, Jack R. Eggleston, Matthew Nicotra, C.-L. Chiu, Mark Henneberg, Heather Best, Jay Cederberg, Stephen Holnbeck, R. Lotspeich, Christopher Laveau, Tommaso Moramarco, Mark Jones, Jonathan Gourley, Danny Wasielewski
By
Water Resources Mission Area, Colorado Water Science Center, National Innovation Center, Pennsylvania Water Science Center

Investigation of pier scour in coarse-bed streams in Montana, 2001 through 2007 Investigation of pier scour in coarse-bed streams in Montana, 2001 through 2007

A primary goal of ongoing field research of bridge scour is improvement of scour-prediction equations so that pier-scour depth is predicted accurately-an important element of hydraulic analysis and design of highway bridges that cross streams, rivers, and other waterways. Scour depth for piers in streambeds with a mixture of sand, gravel, cobbles, and boulders (coarse-bed streams, which...
Authors
Stephen Holnbeck
By
Water Resources Mission Area, Wyoming-Montana Water Science Center

Sediment-transport investigations of the upper Yellowstone River, Montana, 1999 through 2001: Data collection, analysis, and simulation of sediment transport Sediment-transport investigations of the upper Yellowstone River, Montana, 1999 through 2001: Data collection, analysis, and simulation of sediment transport

The upper Yellowstone River in Montana is an important State and national water resource, providing recreational, agricultural, and commercial benefits. Floods in 1996 and 1997, with recorded peak discharges having recurrence intervals close to 100 years, caused substantial streambank erosion and hill- slope mass wasting. Large quantities of sand-, gravel-, and cobble-sized material...
Authors
Stephen Holnbeck

Evaluation of pier-scour equations for coarse-bed streams Evaluation of pier-scour equations for coarse-bed streams

Streambed scour at bridge piers is among the leading causes of bridge failure in the United States. Several pier-scour equations have been developed to calculate potential scour depths at existing and proposed bridges. Because many pier-scour equations are based on data from laboratory flumes and from cohesionless silt- and sand-bottomed streams, they tend to overestimate scour for piers...
Authors
Katherine Chase, Stephen Holnbeck

Rapid-estimation method for assessing scour at highway bridges Rapid-estimation method for assessing scour at highway bridges

A method was developed by the U.S. Geological Survey for rapid estimation of scour at highway bridges using limited site data and analytical procedures to estimate pier, abutment, and contraction scour depths. The basis for the method was a procedure recommended by the Federal Highway Administration for conducting detailed scour investigations, commonly referred to as the Level 2 method...
Authors
Stephen Holnbeck

Method for rapid estimation of scour at highway bridges based on limited site data Method for rapid estimation of scour at highway bridges based on limited site data

Limited site data were used to develop a method for rapid estimation of scour at highway bridges. The estimates can be obtained in a matter of hours rather than several days as required by more-detailed methods. Such a method is important because scour assessments are needed to identify scour-critical bridges throughout the United States. Using detailed scour-analysis methods and scour...
Authors
S.R. Holnbeck, Charles Parrett

Rapid-Estimation Method for Assessing Scour at Highway Bridges Based on Limited Site Data Rapid-Estimation Method for Assessing Scour at Highway Bridges Based on Limited Site Data

No abstract available.
Authors
Stephen Holnbeck, Charles Parrett
By
Water Resources Mission Area

Procedures for estimating unit hydrographs for large floods at ungaged sites in Montana Procedures for estimating unit hydrographs for large floods at ungaged sites in Montana

Flood hydrographs for 26 gaging stations and rainfall data were used together with a rainfall-runoff simulation model to derive unit hydrographs and important unit-hydrograph variables. Methods were developed for estimating unit hydrographs at ungaged sites using either the Clark or dimensionless unit-hydrograph methods. The 26 derived unit hydrographs were compared with those calculated...
Authors
Stephen Holnbeck, Charles Parrett

Relation between largest known flood discharge and elevation in Montana Relation between largest known flood discharge and elevation in Montana

Previous studies relating unit discharge to elevation indicated that large floods in the Rocky Mountains may be limited by elevation. However, high-elevation data are sparse in Montana and the indications may not be entirely correct. Based on data at 19 sites in Montana, a strong log-linear relation exists between large-flood discharge and drainage area. The use of unit discharge (peak...
Authors
Charles Parrett, Stephen Holnbeck

Bridge scour and change in contracted section, Razor Creek Bridge scour and change in contracted section, Razor Creek

Two large floods, 3 and 4 times the estimated 100-year peak discharge, occurred in 1986 and 1991 at a timber-pile bridge over Razor Creek in Montana. A bridge section surveyed after the 1991 flood was compared with a 1955 design section and showed total scour of 0.85 m at the left abutment, 2.23 m at the right abutment, and 0. 94 m at the pile bents. Calculated total scour based on...
Authors
Stephen Holnbeck, Charles Parrett, Todd Tillinger

Estimation of unit hydrographs for large floods at ungaged sites in Montana Estimation of unit hydrographs for large floods at ungaged sites in Montana

Methods were developed for estimating unit hydro- graphs at ungaged sites in Montana using either the Clark or dimensionless unit-hydrograph method. Flood hydrograph data for 26 U.S. Geological Survey streamflow-gaging stations and rainfall data were used together with a rainfall-runoff simulation model (HEC-1) to derive unit hydrographs and important unit-hydrograph variables. A...
Authors
S.R. Holnbeck, Charles Parrett

Science and Products

Measuring bridge scour on Clark Fork River near Superior, MT

Bridge Scour in Montana

Bridge scour is the erosion of streambed material away from pier foundations and abutments and is the leading cause of bridge failure in the United States (Richardson and Davis, 2001). Since the early 1990s, the U.S. Geological Survey (USGS) and the Montana Department of Transportation (MDT) have had a cooperative bridge scour project in Montana.
By
Wyoming-Montana Water Science Center
Bridge Scour in Montana

Bridge Scour in Montana

Bridge scour is the erosion of streambed material away from pier foundations and abutments and is the leading cause of bridge failure in the United States (Richardson and Davis, 2001). Since the early 1990s, the U.S. Geological Survey (USGS) and the Montana Department of Transportation (MDT) have had a cooperative bridge scour project in Montana.
Learn More

Channel geometry for upstream and downstream cross sections at selected bridge sites in Montana, 2022 Channel geometry for upstream and downstream cross sections at selected bridge sites in Montana, 2022

The U.S. Geological Survey, in cooperation with the Montana Department of Transportation (MDT), collected cross-section data on the upstream and downstream sides at 18 sites involving 20 bridges in Montana during the 2022 calendar year. The purpose of the data collection is to determine if scour and channel instability occur in the vicinity of the bridge structures. Data were processed...
By
Wyoming-Montana Water Science Center

Channel geometry for upstream and downstream cross sections at selected bridge sites in Montana, 2021 Channel geometry for upstream and downstream cross sections at selected bridge sites in Montana, 2021

The U.S. Geological Survey, in cooperation with the Montana Department of Transportation (MDT), collected cross-section data on the upstream and downstream sides at selected bridges in Montana during the 2021 calendar year. The purpose of the data collection is to determine if scour and channel instability occur in the vicinity of the bridge structures. Data were processed, analyzed, and...
By
Wyoming-Montana Water Science Center

Channel geometry for upstream and downstream cross sections at selected bridge sites in Montana, 2020 Channel geometry for upstream and downstream cross sections at selected bridge sites in Montana, 2020

The U.S. Geological Survey, in cooperation with the Montana Department of Transportation (MDT), collected cross-section data on the upstream and downstream sides at selected bridges in Montana during the 2020 calendar year. The purpose of the data collection is to determine if scour and channel instability occur in the vicinity of the bridge structures. Data were processed, analyzed, and...
By
Wyoming-Montana Water Science Center

Water-surface elevation data and flood and floodway boundaries for the upper Yellowstone River, Montana Water-surface elevation data and flood and floodway boundaries for the upper Yellowstone River, Montana

No abstract available.
By
Yellowstone
Surveying water surface along with other methods to describe scour
Surveying water surface along with other methods to describe scour
Surveying water surface along with other methods to describe scour
Surveying water surface along with other methods to describe scour

Surveying water surface along with other methods to describe scour

Surveying water surface along with other methods to describe scour

Surveying water surface to tie into bathymetry measurments on Bitterroot River near Hamilton, MT to describe scour near the bridge.

By
Wyoming-Montana Water Science Center
Surveying water surface along with other methods to describe scour

Surveying water surface along with other methods to describe scour

Surveying water surface along with other methods to describe scour

Surveying water surface to tie into bathymetry measurments on Bitterroot River near Hamilton, MT to describe scour near the bridge.

By
Wyoming-Montana Water Science Center
Ground point survey with robotic total station and prism and rod techniques, measuring depth of streambed to assess b
Ground point survey with total station to measure depth to streambed
Ground point survey with total station to measure depth to streambed
Ground point survey with robotic total station and prism and rod techniques, measuring depth of streambed to assess b

Ground point survey with total station to measure depth to streambed

Ground point survey with total station to measure depth to streambed

Ground point survey with Trimble S6 robotic total station and prism and rod techniques, measuring depth of streambed to assess bridge scour on West Gallatin River near Belgrade, MT

By
Wyoming-Montana Water Science Center
Ground point survey with robotic total station and prism and rod techniques, measuring depth of streambed to assess b

Ground point survey with total station to measure depth to streambed

Ground point survey with total station to measure depth to streambed

Ground point survey with Trimble S6 robotic total station and prism and rod techniques, measuring depth of streambed to assess bridge scour on West Gallatin River near Belgrade, MT

By
Wyoming-Montana Water Science Center
Bathymetry survey measuring streambed depths along pier
Bathymetry survey measuring streambed depths along bridge pi
Bathymetry survey measuring streambed depths along bridge pi
Bathymetry survey measuring streambed depths along pier

Bathymetry survey measuring streambed depths along bridge pi

Bathymetry survey measuring streambed depths along bridge pi

Bathymetry survey with Trimble S6 robotic total station, hydrolite single-beam echosounder transducer, and HYPACK software, measuring streambed depths along bridge pier on Beaverhead River in Twin Bridges, MT

By
Wyoming-Montana Water Science Center
Bathymetry survey measuring streambed depths along pier

Bathymetry survey measuring streambed depths along bridge pi

Bathymetry survey measuring streambed depths along bridge pi

Bathymetry survey with Trimble S6 robotic total station, hydrolite single-beam echosounder transducer, and HYPACK software, measuring streambed depths along bridge pier on Beaverhead River in Twin Bridges, MT

By
Wyoming-Montana Water Science Center
Measuring bridge scour on Clark Fork River near Superior, MT
Measuring bridge scour on Clark Fork River near Superior, MT
Measuring bridge scour on Clark Fork River near Superior, MT
Measuring bridge scour on Clark Fork River near Superior, MT

Measuring bridge scour on Clark Fork River near Superior, MT

Measuring bridge scour on Clark Fork River near Superior, MT

Measuring bridge scour on Clark Fork River near Superior, MT (April 4, 2007)

By
Wyoming-Montana Water Science Center
Measuring bridge scour on Clark Fork River near Superior, MT

Measuring bridge scour on Clark Fork River near Superior, MT

Measuring bridge scour on Clark Fork River near Superior, MT

Measuring bridge scour on Clark Fork River near Superior, MT (April 4, 2007)

By
Wyoming-Montana Water Science Center

Evaluating the use of video cameras to estimate bridge scour potential at four bridges in southwestern Montana Evaluating the use of video cameras to estimate bridge scour potential at four bridges in southwestern Montana

The U.S. Geological Survey, in cooperation with the Montana Department of Transportation, installed cameras and large-scale particle image velocimetry (LSPIV) recording equipment at four sites where the U.S. Geological Survey and Montana Department of Transportation are monitoring bridge scour using other methods. Determination of stream velocities is an important component of hydraulic...
Authors
Daniel Armstrong, Stephen Holnbeck, Katherine Chase
By
Water Resources Mission Area, Wyoming-Montana Water Science Center

Near-field remote sensing of surface velocity and river discharge using radars and the probability concept at 10 USGS streamgages Near-field remote sensing of surface velocity and river discharge using radars and the probability concept at 10 USGS streamgages

Near-field remote sensing of surface velocity and river discharge (discharge) were measured using coherent, continuous wave Doppler and pulsed radars. Traditional streamgaging requires sensors be deployed in the water column; however, near-field remote sensing has the potential to transform streamgaging operations through non-contact methods in the U.S. Geological Survey (USGS) and other...
Authors
John Fulton, Christopher Mason, Jack R. Eggleston, Matthew Nicotra, C.-L. Chiu, Mark Henneberg, Heather Best, Jay Cederberg, Stephen Holnbeck, R. Lotspeich, Christopher Laveau, Tommaso Moramarco, Mark Jones, Jonathan Gourley, Danny Wasielewski
By
Water Resources Mission Area, Colorado Water Science Center, National Innovation Center, Pennsylvania Water Science Center

Investigation of pier scour in coarse-bed streams in Montana, 2001 through 2007 Investigation of pier scour in coarse-bed streams in Montana, 2001 through 2007

A primary goal of ongoing field research of bridge scour is improvement of scour-prediction equations so that pier-scour depth is predicted accurately-an important element of hydraulic analysis and design of highway bridges that cross streams, rivers, and other waterways. Scour depth for piers in streambeds with a mixture of sand, gravel, cobbles, and boulders (coarse-bed streams, which...
Authors
Stephen Holnbeck
By
Water Resources Mission Area, Wyoming-Montana Water Science Center

Sediment-transport investigations of the upper Yellowstone River, Montana, 1999 through 2001: Data collection, analysis, and simulation of sediment transport Sediment-transport investigations of the upper Yellowstone River, Montana, 1999 through 2001: Data collection, analysis, and simulation of sediment transport

The upper Yellowstone River in Montana is an important State and national water resource, providing recreational, agricultural, and commercial benefits. Floods in 1996 and 1997, with recorded peak discharges having recurrence intervals close to 100 years, caused substantial streambank erosion and hill- slope mass wasting. Large quantities of sand-, gravel-, and cobble-sized material...
Authors
Stephen Holnbeck

Evaluation of pier-scour equations for coarse-bed streams Evaluation of pier-scour equations for coarse-bed streams

Streambed scour at bridge piers is among the leading causes of bridge failure in the United States. Several pier-scour equations have been developed to calculate potential scour depths at existing and proposed bridges. Because many pier-scour equations are based on data from laboratory flumes and from cohesionless silt- and sand-bottomed streams, they tend to overestimate scour for piers...
Authors
Katherine Chase, Stephen Holnbeck

Rapid-estimation method for assessing scour at highway bridges Rapid-estimation method for assessing scour at highway bridges

A method was developed by the U.S. Geological Survey for rapid estimation of scour at highway bridges using limited site data and analytical procedures to estimate pier, abutment, and contraction scour depths. The basis for the method was a procedure recommended by the Federal Highway Administration for conducting detailed scour investigations, commonly referred to as the Level 2 method...
Authors
Stephen Holnbeck

Method for rapid estimation of scour at highway bridges based on limited site data Method for rapid estimation of scour at highway bridges based on limited site data

Limited site data were used to develop a method for rapid estimation of scour at highway bridges. The estimates can be obtained in a matter of hours rather than several days as required by more-detailed methods. Such a method is important because scour assessments are needed to identify scour-critical bridges throughout the United States. Using detailed scour-analysis methods and scour...
Authors
S.R. Holnbeck, Charles Parrett

Rapid-Estimation Method for Assessing Scour at Highway Bridges Based on Limited Site Data Rapid-Estimation Method for Assessing Scour at Highway Bridges Based on Limited Site Data

No abstract available.
Authors
Stephen Holnbeck, Charles Parrett
By
Water Resources Mission Area

Procedures for estimating unit hydrographs for large floods at ungaged sites in Montana Procedures for estimating unit hydrographs for large floods at ungaged sites in Montana

Flood hydrographs for 26 gaging stations and rainfall data were used together with a rainfall-runoff simulation model to derive unit hydrographs and important unit-hydrograph variables. Methods were developed for estimating unit hydrographs at ungaged sites using either the Clark or dimensionless unit-hydrograph methods. The 26 derived unit hydrographs were compared with those calculated...
Authors
Stephen Holnbeck, Charles Parrett

Relation between largest known flood discharge and elevation in Montana Relation between largest known flood discharge and elevation in Montana

Previous studies relating unit discharge to elevation indicated that large floods in the Rocky Mountains may be limited by elevation. However, high-elevation data are sparse in Montana and the indications may not be entirely correct. Based on data at 19 sites in Montana, a strong log-linear relation exists between large-flood discharge and drainage area. The use of unit discharge (peak...
Authors
Charles Parrett, Stephen Holnbeck

Bridge scour and change in contracted section, Razor Creek Bridge scour and change in contracted section, Razor Creek

Two large floods, 3 and 4 times the estimated 100-year peak discharge, occurred in 1986 and 1991 at a timber-pile bridge over Razor Creek in Montana. A bridge section surveyed after the 1991 flood was compared with a 1955 design section and showed total scour of 0.85 m at the left abutment, 2.23 m at the right abutment, and 0. 94 m at the pile bents. Calculated total scour based on...
Authors
Stephen Holnbeck, Charles Parrett, Todd Tillinger

Estimation of unit hydrographs for large floods at ungaged sites in Montana Estimation of unit hydrographs for large floods at ungaged sites in Montana

Methods were developed for estimating unit hydro- graphs at ungaged sites in Montana using either the Clark or dimensionless unit-hydrograph method. Flood hydrograph data for 26 U.S. Geological Survey streamflow-gaging stations and rainfall data were used together with a rainfall-runoff simulation model (HEC-1) to derive unit hydrographs and important unit-hydrograph variables. A...
Authors
S.R. Holnbeck, Charles Parrett
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