Tons Of Sediment Research Articles

Oceans get 1.3 million tons of sediment daily from U.S. rivers

Rivers in the conterminous United States discharge an average of about 1.3 million tons of sediment every day according to a report released by the U.S. Geological Survey. The report notes that most of this soil and rock debris is dumped into the Gulf of Mexico. The Mississippi River alone discharges about 245 million tons of sediment every year into the Gulf, which is almost as much as all other U.S. rivers combined.USGS hydrologist, William F. Curtis, senior author of the report, said: ‘Knowledge of the amount of sediment transported by our rivers is important for a variety of reasons. For example, because sediment yields are an indication of the rates of erosion in a basin, they can be used to assess land use practices and to plan reservoirs with enough space to store the expected sediment accumulations and still function effectively as water reservoirs. Similarly, sediment yields are a good indication of the amount of sediment that must be dredged from harbors and channels to maintain navigation depths.’

Pleistocene Ice-Rafted Pebble Abundance, Eastern North Atlantic Ocean: ABSTRACT

Detailed examination of a suite of 8 deep-sea cores collected by USNS Kane, north of 48°N lat., in the eastern North Atlantic Ocean indicates an unusually high abundance of coarser than sand-size rafted debris. An average of 3 pebbles per core, each weighing greater than 8 g, characterizes the suite. In fact, the average weight for all pebbles found was 30 g. Assuming that these averages are compatible for the rest of the eastern North Atlantic, and assuming an average age of 300,000 years for the 8 cores, it has been calculated that over 2.6 × 1013 metric tons of coarse debris has been transported from Europe, Iceland, and the Faeroe Islands by ice-rafting since late middle Pleistocene time. If coarse debris represents a total of only 20% of all ice- afted sediment, then in the eastern North Atlantic, over 1.3 × 1014 metric tons of sediment has been ice-rafted in the last 300,000 years. End_of_Article - Last_Page 640------------

Tidal-Flat Erosion and Sedimentation by Ice, St. Lawrence Estuary: ABSTRACT

The action of ice on the shores of the St. Lawrence estuary has been studied since 1964. Shore ice in that area is a powerful agent of erosion and sedimentation. Annually, millions of tons of sediments from clay to boulder size are removed and carried by ice. Erosion of muddy tidal flats and salt marshes is especially significant; a peculiar sedimentary facies results. The St. Lawrence is one of the best sites to study the geologic action of ice because of the presence of (1) relatively large tidal flats, (2) high tidal range and strong tidal current, and (3) ice during a minimum of 4 months. End_of_Article - Last_Page 844------------

Geomorphic effects of the May 1967 flood in Graburn Watershed, Cypress Hills, Alberta, Canada

In May 1967, a flood which was at least a 50 year flood occurred in Graburn watershed in the Alberta Cypress Hills. During the 6 day flood period from May 16th to May 21st, 1023 tons of sediment were removed in solution, 17400 tons in suspension and 28300 tons as bed load. An average thickness of 0.09 feet of fresh overbank material was deposited by the floodwaters. Gravel, as well as the more normal vertical accretion silt and clay material was laid down on the floodplain surface. Comparison of the rate of denudation calculated for the flood (0.0013 feet) with other reported rates, suggest that it is not as high as might be expected for a flood of this magnitude.

The Sediment Yield of Major Rivers of the World

The amount of suspended sediment transported by rivers to the seas each year is tabulated. The major rivers are ranked in order of tons of sediment transported per year and drainage area and water discharge data are included. The rivers are listed by, continents in subsequent tables with data on drainage area, annual sediment yields in tons, sediment production rates in tons per square mile per year, the years of sediment measurement, and the sources of data. This sample represents more than one‐third of the land contributing water‐borne sediment to the seas and, if representative, indicates an annual world sediment yield of 20 billion (20 × 109) tons. The data suggest that Africa, Europe, and Australia have very low sediment yields (<120 tons per square mile per year), South America's rate is low, North America's is moderate, and Asia's is high to the degree of yielding up to 80% of the sediment reaching the oceans annually.

Some Economic Aspects of Urban Sedimentation

Recent studies have amply demonstrated that there are large quantities of sediment polluting both land and watercourses. They have indicated that much of this sediment is originating in urbanized and urbanizing areas. For example, in the Potomac River Basin, streams draining the most heavily farmed areas generally discharge 200 to 400 tons of sediment per square mile of drainage area. But almost none of the streams

RECENT MARINE SEDIMENTS IN SAANICH INLET, A STAGNANT MARINE BASIN1

Saanich Inlet, a fjord on the eastern side of Vancouver Island, has H2S in the bottom waters during most of the year. Recent marine sediments in the inlet include three distinctly different types. Black, fine‐grained, varved claycy silts containing H2S and large amounts of diatom frustules and carbonaceous organic materials occur in the central part of the inlet. Olive‐gray silts with moderate concentrations of organic materials and reducing capacities occur on the sill at the entrance to the inlet. The nearshore sands and gravels have low organic contents and low reducing capacity. Carbonate‐rich sediments occur near a limestone quarry and cement factory. A carbon‐nitrogen ratio of 7 is typical of the sediments in the inlet.Five sources of sediment can be distinguished: (1) carbonaceous and siliceous organic matter from marine organisms, principally planktonic diatoms, (2) suspended sediment in low‐salinity water brought from the Fraser and Cowichan rivers, (3) material eroded from adjacent shorelines, (4) streams discharging into the inlet, and (5) the cement plant and limestone quarry at Bamberton. The varved sediments in the central basin consist of olive‐gray laminac, apparently formed during the peak diatom production in spring or summer and olive‐black laminac, containing larger mounts of terrigenous sediment, probably formed during the autumn and winter. Zones of nonlaminated sediment may be formed by terrigenous material or by the disruption of the laminated sediment by other physical processes. No evidence of burrowing organisms has been detected.Four to 6 mm of wet sediment are deposited each year in the southern portion of the inlet. If this rate is typical of the basin as a whole, approximately 105 metric tons of sediment are deposited each year. At least 25–35% of this sediment is derived from marine organisms.

Sediment in Small Reservoirs Due to Urbanization

Expanding urbanization activities may cause serious sediment deposition in small reservoirs. An example is that of Lake Barcroft near Washington, D. C., where 19 acre-ft or 25,000 tons of sediment has been deposited for each square mile of completed residential construction. Factors affecting the sedimentology processes in areas under urbanization are found to be similar to, but more difficult to evaluate than, those applying to rural conditions.

Discussion

Professor F. W. Shotton said that important information had been obtained from a very limited sample of material. The faunal list might appear small compared with that from Upton Warren (which was in process of publication) but when it was realized that over half a ton of sediment from Upton Warren was washed, whereas the material available from Fladbury amounted to only a few pounds, it would be appreciated how rich the Fladbury deposit was and how informative it could be if ever working of the gravel-pit allowed examination of new material. As it was, Mr. Coope had demonstrated a land fauna representing a more rigorous climate than that shown by any other fauna yet studied in the British Pleistocene. It was to be expected that insects would provide answers to many questions of ecology, but Mr. Coope had also, by a selection of appropriate species, shown how valuable beetles could be in the evaluation of past climate. There was no doubt that the study of Pleistocene insects opened up a wide and important field of future work. Dr. M. E. Tomlinson said that she was particularly pleased that the result of the carbon 14 dating of the peat gave added support to the view of Dr. L. J. Wills that No. 2 Avon Terrace and the Main Terrace of the Severn, into which it merged at Tewkesbury, could be correlated with the last glaciation of the West Midlands when Irish Sea ice occupied the Cheshire plain.

Sediment Transport in Money Creek

1952 and 1955 to determine deposition of sediment; particle size distribution analyses of 30 sediment samples were utilized to determine tons of sediment deposited; curves of water discharge versus sediment discharge were computed utilizing Einstein procedure, Schoklitsch formula and DuBoys formula.

Future of Lake Mead and Elephant Butte Reservoir

The gates in the by-pass tunnels at Boulder Dam (Arizona-Nevada) were closed February 1, 1935, and the storing of water and sediment began. In ten years following that date some 1,500 million tons of sediment passed the Bright Angel silt-sampling and gaging station in the Grand Canyon, in Arizona. Virtually all of this sediment was arrested by Boulder Dam. There is also an added contrib ution from the 30,000 sq miles of drainage area between the Grand Canyon Station and Boulder Dam.