Ronald Griffiths
Ron Griffiths is a hydrologist with the Southwest Biological Science Center.
Science and Products
Filter Total Items: 32
Optimal timing of high-flow experiments for sandbar deposition 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...
Authors
David J. Topping, Paul E. Grams, Ronald E. Griffiths, Joseph E. Hazel, Matthew Kaplinski, David J. Dean, Nicholas Voichick, Joel A. Unema, Thomas A. Sabol
Long-term evolution of sand transport through a river network: Relative influences of a dam versus natural changes in grain size from sand waves 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...
Authors
David J. Topping, Erich R. Mueller, John C. Schmidt, Ronald E. Griffiths, David J. Dean, Paul E. Grams
Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations 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...
Authors
Nicholas Voichick, David J. Topping, Ronald E. Griffiths
Importance of measuring discharge and sediment transport in lesser tributaries when closing sediment budgets 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...
Authors
Ronald E. Griffiths, David J. Topping
Water clarity of the Colorado River—Implications for food webs and fish communities 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...
Authors
Nicholas Voichick, Theodore A. Kennedy, David J. 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 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...
Authors
David J. Topping, Scott Wright, Ronald E. Griffiths, David J. Dean
Science and Products
Filter Total Items: 32
Optimal timing of high-flow experiments for sandbar deposition 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...
Authors
David J. Topping, Paul E. Grams, Ronald E. Griffiths, Joseph E. Hazel, Matthew Kaplinski, David J. Dean, Nicholas Voichick, Joel A. Unema, Thomas A. Sabol
Long-term evolution of sand transport through a river network: Relative influences of a dam versus natural changes in grain size from sand waves 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...
Authors
David J. Topping, Erich R. Mueller, John C. Schmidt, Ronald E. Griffiths, David J. Dean, Paul E. Grams
Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations 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...
Authors
Nicholas Voichick, David J. Topping, Ronald E. Griffiths
Importance of measuring discharge and sediment transport in lesser tributaries when closing sediment budgets 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...
Authors
Ronald E. Griffiths, David J. Topping
Water clarity of the Colorado River—Implications for food webs and fish communities 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...
Authors
Nicholas Voichick, Theodore A. Kennedy, David J. 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 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...
Authors
David J. Topping, Scott Wright, Ronald E. Griffiths, David J. Dean