Ronald Griffiths
Ron Griffiths is a hydrologist with the Southwest Biological Science Center.
Science and Products
Filter Total Items: 26
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
Authors
Nicholas Voichick, David Topping, Ronald E. Griffiths
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
Authors
Ronald E. Griffiths, David Topping
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
Authors
Nicholas Voichick, Theodore A. Kennedy, David Topping, Ronald E. Griffiths, Kyrie Fry
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
Authors
David Topping, Scott Wright, Ronald E. Griffiths, David Dean
Sediment supply versus local hydraulic controls on sediment transport and storage in a river with large sediment loads
The Rio Grande in the Big Bend region of Texas, USA, and Chihuahua and Coahuila, Mexico, undergoes rapid geomorphic changes as a result of its large sediment supply and variable hydrology; thus, it is a useful natural laboratory to investigate the relative importance of flow strength and sediment supply in controlling alluvial channel change. We analyzed a suite of sediment transport and geomorphi
Authors
David Dean, David Topping, John C. Schmidt, Ronald E. Griffiths, Thomas A. Sabol
Using 15-minute acoustic data to analyze suspended-sediment dynamics in the Rio Grande in the Big Bend Region
The Rio Grande in the Big Bend region is subject to rapid geomorphic change consisting of channel narrowing during years of low flow, and channel widening during rare, large, long duration floods. Since the 1940s, there have been large declines in mean and peak stream flow, and the channel has progressively narrowed. Large, channel widening floods are infrequent and have failed to widen the channe
Authors
David Dean, David Topping, Ronald E. Griffiths, Thomas A. Sabol, John C. Schmidt, Jeffery B. Bennett
Inaccuracies in sediment budgets arising from estimations of tributary sediment inputs: an example from a monitoring network on the southern Colorado plateau
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 channel reach is in a state of sediment accumulation, deficit or stasis. Many studies
Authors
Ronald E. Griffiths, David Topping
Design of a sediment-monitoring gaging network on ephemeral tributaries of the Colorado River in Glen, Marble, and Grand Canyons, Arizona
Management of sediment in rivers downstream from dams requires knowledge of both the sediment supply and downstream sediment transport. In some dam-regulated rivers, the amount of sediment supplied by easily measured major tributaries may overwhelm the amount of sediment supplied by the more difficult to measure lesser tributaries. In this first class of rivers, managers need only know the amount
Authors
Ronald E. Griffiths, David J. Topping, Robert S. Anderson, Gregory S. Hancock, Theodore S. Melis
Physically based method for measuring suspended-sediment concentration and grain size using multi-frequency arrays of acoustic-doppler profilers
As the result of a 12-year program of sediment-transport research and field testing on the Colorado River (6 stations in UT and AZ), Yampa River (2 stations in CO), Little Snake River (1 station in CO), Green River (1 station in CO and 2 stations in UT), and Rio Grande (2 stations in TX), we have developed a physically based method for measuring suspended-sediment concentration and grain size at 1
Authors
David J. Topping, Scott Wright, Ronald E. Griffiths, David Dean
Design and maintenance of a network for collecting high-resolution suspended-sediment data at remote locations on rivers, with examples from the Colorado River
Management of sand and finer sediment in fluvial settings has become increasingly important for reasons ranging from endangered-species habitat to transport of sediment-associated contaminants. In all rivers, some fraction of the suspended load is transported as washload, and some as suspended bed material. Typically, the washload is composed of silt-and-clay-size sediment, and the suspended bed m
Authors
Ronald E. Griffiths, David J. Topping, Timothy Andrews, Glenn E. Bennett, Thomas A. Sabol, Theodore S. Melis
Sediment-transport during three controlled-flood experiments on the Colorado River downstream from Glen Canyon Dam, with implications for eddy-sandbar deposition in Grand Canyon National Park
Three large-scale field experiments were conducted on the Colorado River downstream from Glen Canyon Dam in 1996, 2004, and 2008 to evaluate whether artificial (that is, controlled) floods released from the dam could be used in conjunction with the sand supplied by downstream tributaries to rebuild and sustainably maintain eddy sandbars in the river in Grand Canyon National Park. Higher suspended-
Authors
David J. Topping, David M. Rubin, Paul E. Grams, Ronald E. Griffiths, Thomas A. Sabol, Nicholas Voichick, Robert B. Tusso, Karen M. Vanaman, Richard R. McDonald
Field evaluation of sediment-concentration errors arising from Non-Isokinetic intake efficiency in depth-integrating suspended-sediment bag samplers
No abstract available.
Authors
Thomas A. Sabol, David J. Topping, Ronald E. Griffiths
Science and Products
Filter Total Items: 26
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
Authors
Nicholas Voichick, David Topping, Ronald E. Griffiths
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
Authors
Ronald E. Griffiths, David Topping
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
Authors
Nicholas Voichick, Theodore A. Kennedy, David Topping, Ronald E. Griffiths, Kyrie Fry
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
Authors
David Topping, Scott Wright, Ronald E. Griffiths, David Dean
Sediment supply versus local hydraulic controls on sediment transport and storage in a river with large sediment loads
The Rio Grande in the Big Bend region of Texas, USA, and Chihuahua and Coahuila, Mexico, undergoes rapid geomorphic changes as a result of its large sediment supply and variable hydrology; thus, it is a useful natural laboratory to investigate the relative importance of flow strength and sediment supply in controlling alluvial channel change. We analyzed a suite of sediment transport and geomorphi
Authors
David Dean, David Topping, John C. Schmidt, Ronald E. Griffiths, Thomas A. Sabol
Using 15-minute acoustic data to analyze suspended-sediment dynamics in the Rio Grande in the Big Bend Region
The Rio Grande in the Big Bend region is subject to rapid geomorphic change consisting of channel narrowing during years of low flow, and channel widening during rare, large, long duration floods. Since the 1940s, there have been large declines in mean and peak stream flow, and the channel has progressively narrowed. Large, channel widening floods are infrequent and have failed to widen the channe
Authors
David Dean, David Topping, Ronald E. Griffiths, Thomas A. Sabol, John C. Schmidt, Jeffery B. Bennett
Inaccuracies in sediment budgets arising from estimations of tributary sediment inputs: an example from a monitoring network on the southern Colorado plateau
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 channel reach is in a state of sediment accumulation, deficit or stasis. Many studies
Authors
Ronald E. Griffiths, David Topping
Design of a sediment-monitoring gaging network on ephemeral tributaries of the Colorado River in Glen, Marble, and Grand Canyons, Arizona
Management of sediment in rivers downstream from dams requires knowledge of both the sediment supply and downstream sediment transport. In some dam-regulated rivers, the amount of sediment supplied by easily measured major tributaries may overwhelm the amount of sediment supplied by the more difficult to measure lesser tributaries. In this first class of rivers, managers need only know the amount
Authors
Ronald E. Griffiths, David J. Topping, Robert S. Anderson, Gregory S. Hancock, Theodore S. Melis
Physically based method for measuring suspended-sediment concentration and grain size using multi-frequency arrays of acoustic-doppler profilers
As the result of a 12-year program of sediment-transport research and field testing on the Colorado River (6 stations in UT and AZ), Yampa River (2 stations in CO), Little Snake River (1 station in CO), Green River (1 station in CO and 2 stations in UT), and Rio Grande (2 stations in TX), we have developed a physically based method for measuring suspended-sediment concentration and grain size at 1
Authors
David J. Topping, Scott Wright, Ronald E. Griffiths, David Dean
Design and maintenance of a network for collecting high-resolution suspended-sediment data at remote locations on rivers, with examples from the Colorado River
Management of sand and finer sediment in fluvial settings has become increasingly important for reasons ranging from endangered-species habitat to transport of sediment-associated contaminants. In all rivers, some fraction of the suspended load is transported as washload, and some as suspended bed material. Typically, the washload is composed of silt-and-clay-size sediment, and the suspended bed m
Authors
Ronald E. Griffiths, David J. Topping, Timothy Andrews, Glenn E. Bennett, Thomas A. Sabol, Theodore S. Melis
Sediment-transport during three controlled-flood experiments on the Colorado River downstream from Glen Canyon Dam, with implications for eddy-sandbar deposition in Grand Canyon National Park
Three large-scale field experiments were conducted on the Colorado River downstream from Glen Canyon Dam in 1996, 2004, and 2008 to evaluate whether artificial (that is, controlled) floods released from the dam could be used in conjunction with the sand supplied by downstream tributaries to rebuild and sustainably maintain eddy sandbars in the river in Grand Canyon National Park. Higher suspended-
Authors
David J. Topping, David M. Rubin, Paul E. Grams, Ronald E. Griffiths, Thomas A. Sabol, Nicholas Voichick, Robert B. Tusso, Karen M. Vanaman, Richard R. McDonald
Field evaluation of sediment-concentration errors arising from Non-Isokinetic intake efficiency in depth-integrating suspended-sediment bag samplers
No abstract available.
Authors
Thomas A. Sabol, David J. Topping, Ronald E. Griffiths