Theodore Melis
Science and Products
Bed texture mapping in large rivers using recreational-grade sidescan sonar
The size-distribution and spatial organization of bed sediment, or bed ‘texture’, is a fundamental attribute of natural channels and is one important component of the physical habitat of aquatic ecosystems. ‘Recreational-grade’ sidescan sonar systems now offer the possibility of imaging, and subsequently quantifying bed texture at high resolution...
Hamill, Daniel; Wheaton, Joseph M.; Buscombe, Daniel D.; Grams, Paul E.; Melis, Theodore S. Using large-scale flow experiments to rehabilitate Colorado River ecosystem function in Grand Canyon: Basis for an adaptive climate-resilient strategy
Adaptive management of Glen Canyon Dam is improving downstream resources of the Colorado River in Glen Canyon National Recreation Area and Grand Canyon National Park. The Glen Canyon Dam Adaptive Management Program (AMP), a federal advisory committee of 25 members with diverse special interests tasked to advise the U.S. Department of the Interior...
Miller, Kathleen; Hamlet, Alan F.; Kenney, Douglas S.; Redmond, Kelly T.; Melis, Theodore S.; Pine, William E.; Korman, Josh; Yard, Michael D.; Jain, Shaleen; Pulwarty, Roger S. Surprise and opportunity for learning in Grand Canyon: the Glen Canyon Dam Adaptive Management Program
With a focus on resources of the Colorado River ecosystem below Glen Canyon Dam, the Glen Canyon Dam Adaptive Management Program has included a variety of experimental policy tests, ranging from manipulation of water releases from the dam to removal of non-native fish within Grand Canyon National Park. None of these field-scale experiments has yet...
Melis, Theodore S.; Walters, Carl; Korman, Josh Building sandbars in the Grand Canyon
In 1963, the U.S. Department of the Interior’s Bureau of Reclamation finished building Glen Canyon Dam on the Colorado River in northern Arizona, 25 kilometers upstream from Grand Canyon National Park. The dam impounded 300 kilometers of the Colorado River, creating Lake Powell, the nation’s second largest reservoir. By 1974,...
Grams, Paul E.; Schmidt, John C.; Wright, Scott A.; Topping, David; Melis, Theodore S.; Rubin, David M. Large river bed sediment characterization with low-cost sidecan sonar: Case studies from two setting in the Colorado (Arizona) and Penobscot (Maine) Rivers
Mapping subaqueous riverbed sediment grain size across channels and in nearshore areas typically used by fish and benthic invertebrates is difficult where and when the water flow is too swift or deep to wade yet impractical to access with large boats and instruments. Fluvial characteristics can further constrain sampling options, particularly...
Buscombe, Daniel D.; Grams, Paul E.; Melis, Theodore S.; Smith, Sean
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...
Griffiths, Ronald E.; Topping, David J.; Anderson, Robert S.; Hancock, Gregory S.; Melis, Theodore S. Are large-scale flow experiments informing the science and management of freshwater ecosystems?
Greater scientific knowledge, changing societal values, and legislative mandates have emphasized the importance of implementing large-scale flow experiments (FEs) downstream of dams. We provide the first global assessment of FEs to evaluate their success in advancing science and informing management decisions. Systematic review of 113 FEs across...
Olden, Julian D.; Konrad, Christopher P.; Melis, Theodore S.; Kennard, Mark J.; Freeman, Mary; Mims, Meryl C.; Bray, Erin N.; Gido, Keith B.; Hemphill, Nina P.; Lytle, David A.; McMullen, Laura E.; Pyron, Mark; Robinson, Christopher T.; Schmidt, John C.; Williams, John G.
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...
Griffiths, Ronald E.; Topping, David J.; Andrews, Timothy; Bennett, Glenn E.; Sabol, Thomas A.; Melis, Theodore S. The Glen Canyon Dam adaptive management program: progress and immediate challenges
Adaptive management emerged as an important resource management strategy for major river systems in the United States (US) in the early 1990s. The Glen Canyon Dam Adaptive Management Program (‘the Program’) was formally established in 1997 to fulfill a statutory requirement in the 1992 Grand Canyon Protection Act (GCPA). The GCPA aimed...
Boon, Philip J.; Raven, Paul J.; Hamill, John F.; Melis, Theodore S. Large-scale flow experiments for managing river systems
Experimental manipulations of streamflow have been used globally in recent decades to mitigate the impacts of dam operations on river systems. Rivers are challenging subjects for experimentation, because they are open systems that cannot be isolated from their social context. We identify principles to address the challenges of conducting effective...
Konrad, Christopher P.; Olden, Julian D.; Lytle, David A.; Melis, Theodore S.; Schmidt, John C.; Bray, Erin N.; Freeman, Mary; Gido, Keith B.; Hemphill, Nina P.; Kennard, Mark J.; McMullen, Laura E.; Mims, Meryl C.; Pyron, Mark; Robinson, Christopher T.; Williams, John G. Effects of fluctuating flows and a controlled flood on incubation success and early survival rates and growth of age-0 rainbow trout in a large regulated river
Hourly fluctuations in flow from Glen Canyon Dam were increased in an attempt to limit the population of nonnative rainbow trout Oncorhynchus mykiss in the Colorado River, Arizona, due to concerns about negative effects of nonnative trout on endangered native fishes. Controlled floods have also been conducted to enhance native fish habitat. We...
Korman, Josh; Kaplinski, Matthew; Melis, Theodore S.
Field evaluation of the error arising from inadequate time averaging in the standard use of depth-integrating suspended-sediment samplers
Several common methods for measuring suspended-sediment concentration in rivers in the United States use depth-integrating samplers to collect a velocity-weighted suspended-sediment sample in a subsample of a river cross section. Because depth-integrating samplers are always moving through the water column as they collect a sample, and can collect...
Topping, David J.; Rubin, David M.; Wright, Scott A.; Melis, Theodore S.
USGS Scientists Discuss Climate, Drought and Resource Management at Colorado Plateau Conference
US Geological Survey scientists are presenting on numerous topics related to climate change, drought and resource management at the 13th Biennial Conference of Science and Management on the Colorado Plateau & Southwest Region. Below are some of the newest science topics that the USGS will present.