摘要 :
All reservoirs formed by dams on natural water courses are subject to some degree of sediment inflow and deposition. The problem confronting the project planner is to estimate the rate of deposition and the period of time before t...
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All reservoirs formed by dams on natural water courses are subject to some degree of sediment inflow and deposition. The problem confronting the project planner is to estimate the rate of deposition and the period of time before the sediment will interfere with the useful function of the reservoir. Provisions should be made for sufficient sediment storage in the reservoir at the time of design so as not to impair the reservoir functions during the useful life of the project or during the period of economic analysis.
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A release from Glen Canyon Dam during March-April 1996 was designed to test theeffectiveness with which the riparian environment could be renewed with discharges greatly in excess of the normal powerplant-restricted maximum. Of pr...
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A release from Glen Canyon Dam during March-April 1996 was designed to test theeffectiveness with which the riparian environment could be renewed with discharges greatly in excess of the normal powerplant-restricted maximum. Of primary concern was the rebuilding of sand deposits along the channel sides that are important to the flora and fauna along the river corridor and that provide the only camp sites for riverside visitors of the Grand Canyon National Park. Analysis of the depositional processes with a model of flow, sand transport, and bed evolution shows that the sand deposits formed along the channel sides early during the high flow were affected only slightly by the decline in suspended-sand concentrations over the course of the controlled flood. Modeling results suggest that the removal of a large sand deposit over several hours was not a response to declining suspended-sand concentrations. Comparisons of the controlled-flood deposits with deposits formed during a flood in January 1993 on the Little Colorado River that contributed sufficient sand to raise the suspended-sand concentrations to predam levels in the main stem show that the depositional pattern as well as the magnitude is strongly influenced by the suspended-sand concentrations.
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摘要 :
The long term goal of this project is to develop quantitative models of sediment transport, resuspension, deposition and accumulation on the continental margin.
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The U.S. Geological Survey's Chesapeake Bay River Input Program has updated thenutrient and suspended-sediment load data base for the Susquehanna, Potomac, Patuxent, and Choptank Rivers using a multiple-window, center-estimate reg...
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The U.S. Geological Survey's Chesapeake Bay River Input Program has updated thenutrient and suspended-sediment load data base for the Susquehanna, Potomac, Patuxent, and Choptank Rivers using a multiple-window, center-estimate regression methodology. The revised method optimizes the seven-parameter regression approach that has been used historically by the program. The revised method estimates load using the fifth or center year of a sliding 9-year window. Each year a new model is run for each site and constituent, the most recent year is added, and the previous 4 years of estimates are updated. The fifth year in the 9-7year window is considered the best estimate and is kept in the data base.
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The U.S. Geological Survey, in cooperation with the Kansas Water Office, investigated sediment transport to and from three small impoundments (average surface area of 0.1 to 0.8 square miles) in northeast Kansas during March 2009 ...
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The U.S. Geological Survey, in cooperation with the Kansas Water Office, investigated sediment transport to and from three small impoundments (average surface area of 0.1 to 0.8 square miles) in northeast Kansas during March 2009 through September 2011. Streamgages and continuous turbidity sensors were operated upstream and downstream from Atchison County, Banner Creek, and Centralia Lakes to study the effect of varied watershed characteristics and agricultural practices on sediment transport in small watersheds in northeast Kansas.
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Partial Contents: Stratigraphy and Depositional Environments of Sediments fromFive Cores from Screven and Burke Counties, Georgia; Late Companian (Zone CC 22) Coccoliths from the Millhaven Core, Screven County, Georgia; Late Campa...
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Partial Contents: Stratigraphy and Depositional Environments of Sediments fromFive Cores from Screven and Burke Counties, Georgia; Late Companian (Zone CC 22) Coccoliths from the Millhaven Core, Screven County, Georgia; Late Campanian (Zone CC 22) Coccoliths from the Milhaven Core, Screven County, Georgia; Calcareous Nannofossil Biostratigraphy of Cenozoic Sediments from the Millhaven Core, Screven County, Georgia; Pollen Biostratigraphy of Lower Tertiary Sediments from Five Cores from Screven and Burke Counties, Georgia; Foraminifera from Paleogene Sediments from the Millhaven and Millers Pond Cores, Screven and Burke Counties, Georgia.
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As a result of these natural and human interventions, the Illinois River valleyhas experienced a tremendous amount of sediment deposition in recent years. Many of the 53 or so backwater lakes along the river have lost 30 to 100% o...
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As a result of these natural and human interventions, the Illinois River valleyhas experienced a tremendous amount of sediment deposition in recent years. Many of the 53 or so backwater lakes along the river have lost 30 to 100% of their capacity to sediment deposition. Peoria Lake, a bottomland lake, has lost 68% of its 1903 capacity, and upper Peoria Lake will eventually attain the appearance of an incised river with broad and shallow wetlands on both sides. On the average, about 20.6 million tons of sediment is deposited annually over the entire valley, with a deposition rate of 0.81 to 2.1 inches per year. Numerous alternative solutions can be considered for managing these backwater lakes, including constructing closing structures, periodic and selective dredging, using dredged materials to create artificial islands, diverting high flows, installing management practices on the watershed, and converting some of the backwater lakes to marsh and wetland habitats.
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Sediment data have been collected by the U.S. Geological Survey at 118 streamgaging sites throughout the State beginning in 1935. Enough data were collected at 84 of these sites to calculate an average annual suspended sediment. M...
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Sediment data have been collected by the U.S. Geological Survey at 118 streamgaging sites throughout the State beginning in 1935. Enough data were collected at 84 of these sites to calculate an average annual suspended sediment. Measured average annual yields range from about 680 tons per square mile (238 tonnes per square kilometre) in the 'Driftless Area' to 3.1 tons per square mile in the Northern Highland province. The average suspended-sediment yield for Wisconsin is about 80 tons per square mile per year. Sediment-yield prediction equations for four geographic provinces make it possible to predict average annual sediment yield at any point on 95% of the streams in the State.
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This review of sediment transport at gaging stations near Mount St. Helens wasprepared to: summarize the sediment-transport monitoring program at U.S. Geological Survey gaging stations near Mount St. Helens during 1980-90, list pr...
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This review of sediment transport at gaging stations near Mount St. Helens wasprepared to: summarize the sediment-transport monitoring program at U.S. Geological Survey gaging stations near Mount St. Helens during 1980-90, list principal developments in data collection and analysis methods, identify measurable changes in sediment transport during 1980-90, and identify topics for investigation related to sediment-transport monitoring. This report presents scientific goals and objectives for studies of sediment transport in streams near Mount St. Helens. Principal field observations and developments in methods of data collection and analysis are described in chronological order for the period 1980 to 1990. Sequencies of selected sediment data from gaging stations illustrate sediment transport during storm flows. Geomorphic adjustments in the study area are discussed in this report where they provide background for sediment-transport processes.
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