Theodore "Teo" Melis, Ph.D. (Former Employee)
Science and Products
Filter Total Items: 48
Debris flows and the Colorado River Debris flows and the Colorado River
No abstract available.
Authors
Robert Webb, Theodore S. Melis, Peter Griffiths
Recent sediment studies refute Glen Canyon Dam hypothesis Recent sediment studies refute Glen Canyon Dam hypothesis
Recent studies of sedimentology hydrology, and geomorphology indicate that releases from Glen Canyon Dam are continuing to erode sandbars and beaches in the Colorado River in Grand Canyon National Park, despite attempts to restore these resources. The current strategy for dam operations is based on the hypothesis that sand supplied by tributaries of the Colorado River downstream from the...
Authors
David Rubin, David Topping, John Schmidt, Joe Hazel, Matt Kaplinski, Theodore S. Melis
Observations of environmental change in Grand Canyon, Arizona Observations of environmental change in Grand Canyon, Arizona
Few scientific data have been collected on pre-dam conditions of the Colorado River corridor through Grand Canyon National Park. Using historical diaries, interviews with pre-dam river runners (referred to as the ?Old Timers?), and historical scientific data and observations, we compiled anecdotal information on environmental change in Grand Canyon. The most significant changes are the...
Authors
Robert H. Webb, Theodore S. Melis, Richard A. Valdez
Debris flows and rapids in Grand Canyon; implications for erosion rates and evacuation of sediment from tributary canyons Debris flows and rapids in Grand Canyon; implications for erosion rates and evacuation of sediment from tributary canyons
No abstract available.
Authors
Robert Webb, Peter Griffiths, Theodore S. Melis
Entrainment and transport of cobbles and boulders from debris fans Entrainment and transport of cobbles and boulders from debris fans
No abstract available.
Authors
James Pizzuto, Robert Webb, Peter Griffiths, John Elliott, Theodore S. Melis
Reworking of aggraded debris fans Reworking of aggraded debris fans
No abstract available.
Authors
Robert Webb, Theodore S. Melis, Peter Griffiths, John Elliott
Lava Falls Rapid in Grand Canyon: Effects of Late Holocene debris flows on the Colorado River Lava Falls Rapid in Grand Canyon: Effects of Late Holocene debris flows on the Colorado River
Lava Falls Rapid is the most formidable reach of whitewater on the Colorado River in Grand Canyon and is one of the most famous rapids in the world. Debris flows in 1939, 1954, 1955, 1966, and 1995, as well as prehistoric events, completely changed flow through the rapid. Floods cleared out much of the increased constrictions, but releases from Glen Canyon Dam, including the 1996...
Authors
Robert H. Webb, Theodore S. Melis, Peter Griffiths, John Elliott, Thure Cerling, Robert Poreda, Thomas Wise, James Pizzuto
Initiation of debris flows in tributaries of the Colorado River in Grand Canyon, Arizona Initiation of debris flows in tributaries of the Colorado River in Grand Canyon, Arizona
Debris flows are initiated in tributaries of the Colorado River in Grand Canyon when intense rainfall causes failures in colluvium and (or) bedrock. Most debris flows occur in the summer during localized convective thunderstorms with rainfall intensities as high as 40 mm/hr. Rarer and larger debris flows occur during unusually warm frontal storms in winter. Hourly precipitation data...
Authors
Peter Griffiths, Robert Webb, Theodore S. Melis
Debris flows in Grand Canyon National Park: Peak discharges, flow transformations, and hydrographs Debris flows in Grand Canyon National Park: Peak discharges, flow transformations, and hydrographs
Direct measurements of debris-flow hydrograph and flow behavior in remote drainage areas are rare. We infer hydrographs and flow behavior for recent debris flow in bedrock tributaries of the Colorado River from preserved stratigraphic relations, sedimentology and surface morphology of debris fans and evidence of flow-surface elevations. We propose that 3 types of debris-flow hydrographs...
Authors
Theodore S. Melis, Robert Webb, Peter Griffiths
When the blue-green waters turn red: Historical flooding in Havasu Creek, Arizona When the blue-green waters turn red: Historical flooding in Havasu Creek, Arizona
Havasu Creek, the second largest tributary of the Colorado River in Grand Canyon National Park, attracts numerous visitors each year owing to its spectacular scenery. Perennial streamflow seldom exceeds 2 cubic meters per second (m3/s), but supports important stands of riparian vegetation, forms unique travertine pools, and spills over spectacular waterfalls. Havasu Canyon is home to the...
Authors
Theodore S. Melis, William Phillips, Robert H. Webb, Douglas Bills
Initiation and frequency of debris flows in Grand Canyon, Arizona Initiation and frequency of debris flows in Grand Canyon, Arizona
Debris flows occur in 600 tributaries of the Colorado River in Grand Canyon, Arizona when intense precipitation causes slope failures in bedrock or colluvium. These slurries transport poorly sorted sediment, including very large boulders that form rapids at the mouths of tributaries and control the longitudinal profile of the Colorado River. Although the amount of rainfall on the days of...
Authors
Peter Griffiths, Robert H. Webb, Theodore S. Melis
"The Great Cataract" - Effects of Late Holocene Debris Flows on Lava Falls Rapid, Grand Canyon National National Park, Arizona "The Great Cataract" - Effects of Late Holocene Debris Flows on Lava Falls Rapid, Grand Canyon National National Park, Arizona
Lava Falls Rapid is the most formidable reach of whitewater on the Colorado River in Grand Canyon and is one of the most famous rapids in the world. Although the rapid was once thought to be controlled by the remnants of lava dams of Pleistocene age, Lava Falls was created and is maintained by frequent debris flows from Prospect Canyon. We used 232 historical photographs, of which 121...
Authors
Robert H. Webb, Theodore S. Melis, Thomas Wise, John Elliott
Science and Products
Filter Total Items: 48
Debris flows and the Colorado River Debris flows and the Colorado River
No abstract available.
Authors
Robert Webb, Theodore S. Melis, Peter Griffiths
Recent sediment studies refute Glen Canyon Dam hypothesis Recent sediment studies refute Glen Canyon Dam hypothesis
Recent studies of sedimentology hydrology, and geomorphology indicate that releases from Glen Canyon Dam are continuing to erode sandbars and beaches in the Colorado River in Grand Canyon National Park, despite attempts to restore these resources. The current strategy for dam operations is based on the hypothesis that sand supplied by tributaries of the Colorado River downstream from the...
Authors
David Rubin, David Topping, John Schmidt, Joe Hazel, Matt Kaplinski, Theodore S. Melis
Observations of environmental change in Grand Canyon, Arizona Observations of environmental change in Grand Canyon, Arizona
Few scientific data have been collected on pre-dam conditions of the Colorado River corridor through Grand Canyon National Park. Using historical diaries, interviews with pre-dam river runners (referred to as the ?Old Timers?), and historical scientific data and observations, we compiled anecdotal information on environmental change in Grand Canyon. The most significant changes are the...
Authors
Robert H. Webb, Theodore S. Melis, Richard A. Valdez
Debris flows and rapids in Grand Canyon; implications for erosion rates and evacuation of sediment from tributary canyons Debris flows and rapids in Grand Canyon; implications for erosion rates and evacuation of sediment from tributary canyons
No abstract available.
Authors
Robert Webb, Peter Griffiths, Theodore S. Melis
Entrainment and transport of cobbles and boulders from debris fans Entrainment and transport of cobbles and boulders from debris fans
No abstract available.
Authors
James Pizzuto, Robert Webb, Peter Griffiths, John Elliott, Theodore S. Melis
Reworking of aggraded debris fans Reworking of aggraded debris fans
No abstract available.
Authors
Robert Webb, Theodore S. Melis, Peter Griffiths, John Elliott
Lava Falls Rapid in Grand Canyon: Effects of Late Holocene debris flows on the Colorado River Lava Falls Rapid in Grand Canyon: Effects of Late Holocene debris flows on the Colorado River
Lava Falls Rapid is the most formidable reach of whitewater on the Colorado River in Grand Canyon and is one of the most famous rapids in the world. Debris flows in 1939, 1954, 1955, 1966, and 1995, as well as prehistoric events, completely changed flow through the rapid. Floods cleared out much of the increased constrictions, but releases from Glen Canyon Dam, including the 1996...
Authors
Robert H. Webb, Theodore S. Melis, Peter Griffiths, John Elliott, Thure Cerling, Robert Poreda, Thomas Wise, James Pizzuto
Initiation of debris flows in tributaries of the Colorado River in Grand Canyon, Arizona Initiation of debris flows in tributaries of the Colorado River in Grand Canyon, Arizona
Debris flows are initiated in tributaries of the Colorado River in Grand Canyon when intense rainfall causes failures in colluvium and (or) bedrock. Most debris flows occur in the summer during localized convective thunderstorms with rainfall intensities as high as 40 mm/hr. Rarer and larger debris flows occur during unusually warm frontal storms in winter. Hourly precipitation data...
Authors
Peter Griffiths, Robert Webb, Theodore S. Melis
Debris flows in Grand Canyon National Park: Peak discharges, flow transformations, and hydrographs Debris flows in Grand Canyon National Park: Peak discharges, flow transformations, and hydrographs
Direct measurements of debris-flow hydrograph and flow behavior in remote drainage areas are rare. We infer hydrographs and flow behavior for recent debris flow in bedrock tributaries of the Colorado River from preserved stratigraphic relations, sedimentology and surface morphology of debris fans and evidence of flow-surface elevations. We propose that 3 types of debris-flow hydrographs...
Authors
Theodore S. Melis, Robert Webb, Peter Griffiths
When the blue-green waters turn red: Historical flooding in Havasu Creek, Arizona When the blue-green waters turn red: Historical flooding in Havasu Creek, Arizona
Havasu Creek, the second largest tributary of the Colorado River in Grand Canyon National Park, attracts numerous visitors each year owing to its spectacular scenery. Perennial streamflow seldom exceeds 2 cubic meters per second (m3/s), but supports important stands of riparian vegetation, forms unique travertine pools, and spills over spectacular waterfalls. Havasu Canyon is home to the...
Authors
Theodore S. Melis, William Phillips, Robert H. Webb, Douglas Bills
Initiation and frequency of debris flows in Grand Canyon, Arizona Initiation and frequency of debris flows in Grand Canyon, Arizona
Debris flows occur in 600 tributaries of the Colorado River in Grand Canyon, Arizona when intense precipitation causes slope failures in bedrock or colluvium. These slurries transport poorly sorted sediment, including very large boulders that form rapids at the mouths of tributaries and control the longitudinal profile of the Colorado River. Although the amount of rainfall on the days of...
Authors
Peter Griffiths, Robert H. Webb, Theodore S. Melis
"The Great Cataract" - Effects of Late Holocene Debris Flows on Lava Falls Rapid, Grand Canyon National National Park, Arizona "The Great Cataract" - Effects of Late Holocene Debris Flows on Lava Falls Rapid, Grand Canyon National National Park, Arizona
Lava Falls Rapid is the most formidable reach of whitewater on the Colorado River in Grand Canyon and is one of the most famous rapids in the world. Although the rapid was once thought to be controlled by the remnants of lava dams of Pleistocene age, Lava Falls was created and is maintained by frequent debris flows from Prospect Canyon. We used 232 historical photographs, of which 121...
Authors
Robert H. Webb, Theodore S. Melis, Thomas Wise, John Elliott