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Browsing by Author "Dhamotharan, S."

Now showing 1 - 4 of 4
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    Bedload Transport In A Model Gravel Stream
    (Saint Anthony Falls Laboratory, 1980-12) Dhamotharan, S.; Wood, A.; Parker, Gary; Stefan, Heinz
    The presence of a natural pavement consisting of coarse materials in gravel streams is of great interest with regard to fluvial hydraulics and stream ecology. Very little information is available on the mechanics of pavement formation and its characteristics. In this study, insight into the characteristics of sediment transport and pavement evolution in gravel streams was gained by means of a physical model of a gravel stream in the Pacific Northwest. The results from the geometrically undistorted Froude model (scale 1:8) agreed well with the field data. The agreement was further improved when laboratory data and field data were compared in terms of dimensionless bedload W* and relative Shields shear stress ¢. The W* - ¢ plots allow for the quantification of differences in Reynolds number and roughness which were not or could not be scaled by means of Froude similarity. The study leads to the conclusions that bedload transport in natural gravel streams can be simulated in the laboratory and that prototype behavior can be predicted from laboratory data, The experiments also illustrate that pavement can form under conditions of continuous equilibrium transport of all available sizes of interest. This report was submitted in fulfillment of grant No. EPA R 806632-01. The report covers a project period from July 5, 1979 to January 4, 1980. A first draft of this report was submitted in April, 1980.
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    Dynamic Simulation of Turbidity and its Correction in Lak Chicot, Arkansas, U.S.A.
    (St. Anthony Falls Hydraulic Laboratory, 1989-05) Stefan, Heinz G.; Dhamotharan, S.; Schiebe, Frank R,; Fu, A. Y.; Cardoni, John J.
    Lake Chicot is an oxbow lake that was created more than 600 years ago by the meandering of the Mississippi River. It is located in Chicot County in southeastern Arkansas adjacent to the present Mississippi River (Fig. 1). As the largest natural lake in Arkansas, it earned an early reputation for its good fishing and recreational value.
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    Model Studies of A Cooling Water Discharge Structure Modification - Monticello Nuclear Generating Plant
    (St. Anthony Falls Laboratory, 1980-04) Wetzel, Joseph M.; Dahlin, Warren Q.; Dhamotharan, S.
    The Monticello Nuclear Generating Plant is located on the Mississippi River near Monticello, Minnesota. The genera'l location is shown in Fig. 1- Cooling water is presently discharged through a wide canal directly into the Mississippi River. Northern states Power Company (NSP) has need for preventing fish from entering the canal where they would be subject to cold shock mortality in case of sudden winter shutdown. Modification of the canal outlet to the river has therefore been proposed. The outlet of the canal would be closed with a wall that incorporates an overflow weir. The elevation of the river crest was selected by NSP to minimize the possibility of fish jumping over the weir and entering the canal during winter.
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    Model Studies of the Bed Regime of Alluvial Channels as Influenced by Submerged Groins
    (St. Anthony Falls Hydraulic Laboratory, 1976-03) Dhamotharan, S.; Dahlin, W. Q.; Wetzel, J.
    Experimental studies were conduoted in a straight reach of rectangular channel to determ1ne the dynamic equilibrium depth of scour associated with submerged constrictions or groins. Tests were carried out with various groin geometries in both rigid- and movable-bed models. Velocity traverses were made over the groins and in the constricted region to establish the relationship between the ratio of discharge through the constriction to the total discharge and the relative groin submergence and geometry. Measurements of the eroded bed profile in the constricted region indicated that the equilibrium relative depth of scour was related primarily to the discharge ratio and the constriction ratio. All groin geometries tested demonstrated the capability of providing relatively large scour depths at low stages, and less scour depths at high stages for which a larger portion of the total discharge passed over the groins. Reasonable agreement with predicted relative scour depths was noted for relatively large sediment transport rates.