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Ronald Griffiths

Ron Griffiths is a hydrologist with the Southwest Biological Science Center.

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Brown, sediment-laden water of the Paria River mixes with the clear water of the Colorado River

River Sediment Dynamics

Sediment controls the physical habitat of river ecosystems. Changes in the amount and areal distribution of different sediment types cause changes in river-channel form and river habitat. The amount and type of sediment suspended in the water column determines water clarity. Understanding sediment transport and the conditions under which sediment is deposited or eroded from the various...
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Ecosystems Mission Area, Land Management Research Program, Southwest Biological Science Center
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River Sediment Dynamics

Sediment controls the physical habitat of river ecosystems. Changes in the amount and areal distribution of different sediment types cause changes in river-channel form and river habitat. The amount and type of sediment suspended in the water column determines water clarity. Understanding sediment transport and the conditions under which sediment is deposited or eroded from the various...
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Sediment sampling and surrogates

Sediment Acoustics

The U.S. Geological Survey recognizes the need to provide sediment acoustic training and to develop standardized techniques and practices.
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Water Resources Mission Area
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Sediment Acoustics

The U.S. Geological Survey recognizes the need to provide sediment acoustic training and to develop standardized techniques and practices.
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Surveyed coordinates and elevations in a 2020 resurvey of previously established cross sections on the Green River between Jensen and Ouray, Utah

These data were compiled for/to National Park Service and Upper Colorado River Endangered Fish Recovery Program. Objective(s) of our study were to resurvey previously established cross sections on the Green River, Utah, in, and upstream, from Ouray National Wildlife Refuge to document changes in channel width, depth, and cross-sectional area. These data represent the 2020 resurvey coordinates and
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Southwest Biological Science Center

Surveyed coordinates and elevations in a 2017 resurvey of previously established cross sections on the Little Snake and Yampa rivers in Lily and Deerlodge parks, Colorado

These data were compiled for the National Park Service and Upper Colorado River Endangered Fish Recovery Program. Objective(s) of our study were to resurvey previously established cross sections on the Yampa and Little Snake rivers in the Deerlodge Park area to document changes in channel width, depth, and cross-sectional area. A secondary purpose of this study was to document the location of the
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Southwest Biological Science Center

Surveyed peak-stage elevations, coordinates, and indicator data of strandlines from large floods on the Colorado River in Grand Canyon National Park, Arizona

These data provide a comprehensive survey of peak-stage indicators along the Colorado River corridor between river mile (RM) 0 and RM 87 (see Figure 1 in the associated USGS-SIR). In 2008, the locations of peak-stage indicators in three short reaches downstream from RM 87 were measured using a handheld GPS unit (see Appendix 1 in the associated USGS-SIR). Total-station measurements were made using
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Southwest Biological Science Center
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State of the science and decision support for measuring suspended sediment with acoustic instrumentation

Acoustic instrumentation can be used to provide time-series and discrete estimates of suspended-sediment concentration, load, and sediment particle sizes in fluvial systems, which are essential for creating informed solutions to many sediment-related environmental, engineering, and land management concerns. Historically, scientists have developed relations between suspended sediment characteristic
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Molly S. Wood, Joel T. Groten, Timothy D. Straub, Dan R.W. Haught, Ronald E. Griffiths, Justin A. Boldt, Zulimar Lucena, Jeb E. Brown, Steven E. Suttles, Patrick J. Dickhudt
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Water Resources Mission Area, Ecosystems Mission Area, California Water Science Center, Idaho Water Science Center, Southwest Biological Science Center, Woods Hole Coastal and Marine Science Center, Central Midwest Water Science Center, Upper Midwest Water Science Center

Proceedings of the Fiscal Year 2022 Annual Reporting Meeting to the Glen Canyon Dam Adaptive Management Program

(Hartwell) This report is prepared primarily to account for work conducted and products delivered in FY 2022 by GCMRC and to inform the Technical Work Group of science conducted by GCMRC and its cooperators in support of the Glen Canyon Dam Adaptive Management Program (GCDAMP). It includes a summary of accomplishments, modifications to work plans, results, and recommendations related to projects i
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David Topping, Paul Grams, Emily C. Palmquist, Joel B. Sankey, Helen C. Fairley, Bridget Deemer, Charles Yackulic, Theodore Kennedy, Anya Metcalfe, Maria C. Dzul, David Ward, Mariah Aurelia Giardina, Lucas Bair, Thomas Gushue, Caitlin M. Andrews, Ronald E. Griffiths, David Dean, Keith Kohl, Michael J Moran, Nicholas Voichick, Thomas A. Sabol, Laura A. Tennant, Kimberly Dibble, Michael C. Runge
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Ecosystems Mission Area, Southwest Biological Science Center

Field investigation of sub-isokinetic sampling by the US D-96-type suspended-sediment sampler and its effect on suspended-sediment measurements

Collection of accurate suspended-sediment data using depth-integrating samplers requires that they operate isokinetically, that is, that they sample at the local stream velocity unaffected by the presence of the suspended-sediment sampler. Sub-isokinetic suspended-sediment sampling causes grain-size dependent positive biases in the suspended-sediment concentration measured by the suspended-sedimen
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Thomas A. Sabol, David J. Topping, Ronald E. Griffiths, Guillaume Dramais
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Ecosystems Mission Area, Southwest Biological Science Center

Strandlines from large floods on the Colorado River in Grand Canyon National Park, Arizona

Strandlines of peak-stage indicators (such as driftwood logs, woody debris, and trash) provide valuable data for understanding the maximum stage and extent of inundation during floods. A series of seven strandlines have been preserved along the Colorado River in Grand Canyon National Park, Arizona, USA. A survey and analysis of these strandlines was completed from the Colorado River at Lees Ferry,
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Thomas A. Sabol, Ronald E. Griffiths, David J. Topping, Erich R. Mueller, Robert B. Tusso, Joseph E. Hazel
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Ecosystems Mission Area, Southwest Biological Science Center

Self-limitation of sand storage in a bedrock-canyon river arising from the interaction of flow and grain size

Bedrock-canyon rivers tend to be supply limited because they are efficient transporters of sediment and not because the upstream supply of sediment is small. A byproduct of this supply limitation is that the finer alluvium stored in these rivers has shorter residence times and smaller volumes than in alluvial rivers. To improve our understanding of disequilibrium sediment transport and its effect
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David Topping, Paul Grams, Ronald E. Griffiths, David Dean, Scott A. Wright, Joel A. Unema
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Water Resources Mission Area, Ecosystems Mission Area, Arizona Water Science Center, California Water Science Center, Southwest Biological Science Center

Interpreting flux-based sediment budgets in a habitat context: Linking precise temporal-resolution measurements of sediment flux to spatially robust characterization of channel change

Continuous measurements of sediment transport at reach-bracketing gaging stations allow for the construction of continuous mass-balance sediment budgets for the intervening reach. Although these budgets identify periods of sediment surplus (net deposition) or sediment deficit (net erosion), such analyses cannot identify the locations within the reach where channel change occurs. Because channel ch
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Christina M. Leonard, John C. Schmidt, David Topping, Ronald E. Griffiths
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Ecosystems Mission Area, Southwest Biological Science Center

Optimal timing of high-flow experiments for sandbar deposition

Sediment-transport theory and field measurements indicate that the greatest or most efficient deposition of sand in eddies occurs during controlled floods (a.k.a. High-Flow Experiments or HFEs) when the greatest amount of the finest sand is available on the bed of the Colorado River (Topping and others, 2010). Conducting HFEs when the sand on the bed of the Colorado River is depleted and coarse ca
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David Topping, Paul E. Grams, Ronald E. Griffiths, Joseph E. Hazel, Matthew Kaplinski, David Dean, Nicholas Voichick, Joel Unema, Thomas A. Sabol
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Ecosystems Mission Area, Southwest Biological Science Center

Long-term evolution of sand transport through a river network: Relative influences of a dam versus natural changes in grain size from sand waves

Temporal and spatial nonuniformity in supplies of water and sand in a river network leads to sand transport that is in local disequilibrium with the upstream sand supply. In such river networks, sand is transported downstream as elongating waves in which coupled changes in grain size and transport occur. Depending on the magnitude of each sand‐supplying event and the interval between such events,
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David Topping, Erich R. Mueller, John C. Schmidt, Ronald E. Griffiths, David Dean, Paul E. Grams
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Ecosystems Mission Area, Southwest Biological Science Center

Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations

Turbidity, a measure of water clarity, is monitored for a variety of purposes including (1) to help determine whether water is safe to drink, (2) to establish background conditions of lakes and rivers and detect pollution caused by construction projects and stormwater discharge, (3) to study sediment transport in rivers and erosion in catchments, (4) to manage siltation of water reservoirs, and (5
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Nicholas Voichick, David Topping, Ronald E. Griffiths
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Ecosystems Mission Area, Southwest Biological Science Center

Importance of measuring discharge and sediment transport in lesser tributaries when closing sediment budgets

Sediment budgets are an important tool for understanding how riverine ecosystems respond to perturbations. Changes in the quantity and grain size distribution of sediment within river systems affect the channel morphology and related habitat resources. It is therefore important for resource managers to know if a river reach is in a state of sediment accumulation, deficit or stasis. Many sediment-b
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Ronald E. Griffiths, David Topping
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Ecosystems Mission Area, Groundwater and Streamflow Information Program, Southwest Biological Science Center

Long-term continuous acoustical suspended-sediment measurements in rivers – Theory, evaluation, and results from 14 stations on five rivers

We have developed a physically based method for using two acoustic frequencies to measure suspended-silt-and-clay concentration, suspended-sand concentration, and suspended-sand median grain size in river cross sections at 15-minute intervals over decadal timescales. The method is strongly grounded in the extensive scientific literature on the scattering of sound by suspensions of small particles
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David Topping, Scott A. Wright, Ronald E. Griffiths, David Dean
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Ecosystems Mission Area, Southwest Biological Science Center

Water clarity of the Colorado River—Implications for food webs and fish communities

The closure of Glen Canyon Dam in 1963 resulted in drastic changes to water clarity, temperature, and flow of the Colorado River in Glen, Marble, and Grand Canyons. The Colorado River is now much clearer, water temperature is less variable throughout the year, and the river is much colder in the summer months. The flow—regulated by the dam—is now less variable annually, but has larger daily fluctu
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Nicholas Voichick, Theodore A. Kennedy, David Topping, Ronald E. Griffiths, Kyrie Fry
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Ecosystems Mission Area, Southwest Biological Science Center
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SBSC’s Grand Canyon Monitoring and Research Center Adds Low Earth Orbit (LEO) Satellite Dish to Historic Grand Canyon Sediment Gaging Station

Low earth orbit (LEO) satellite telemetry is an emerging technology that shows promise for improving both USGS scientist and stakeholder access to...

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