Using Sediment-Threshold Theories in Waves and Currents
Fundamentally different threshold-of-motion theories were applied to sand transport in two different coastal environments. Several recommendations for threshold application were reached....
Transport of Grain-Water Mixture by Waves
The numerical modelling of the morphological changes of coastal regions is hampered by the multiplicity of empirical sediment transport formulae. The paper discusses the modes of transport...
The Beginning of Sediment Transport as a Probability-Problem
Sediment transport only takes place when the action of flow (shear stress, velocity) exceeds a critical value. The limit between rest and movement can be given as critical flow velocity,...
Instability of Bed-Surface Composition Due to Sorting Process in a Stream Composed of Sand and Gravel
Wavy patterns of sorting are often observed in a stream composed of sand and gravel, and they are regarded as instability of bed-surface composition due to selective bed-load transport...
Mid-Scale Laboratory Tests on a Two-Dimensional Movable-Bed Sand Model
A two-dimensional physical model was used to simulate wave-induced scour in front of a concrete dike sloped at 1:4. The tests were conducted at the U.S. Army Engineers Waterways Experiment...
The Structure of Intermittent Sand Suspension Events Under Mild Wave Conditions
Nearshore sedimentation processes are being actively investigated through a series of research projects at the University of Miami. Quantitative measurements of waves, currents, and suspended...
Bank Failure and Erosion on the Illinois Waterway
In 1988, bank failure and erosion on the Illinois Waterway were evaluated. Banks were inspected from the air and from a motor vessel; thirty-one sites were examined in detail. Severe erosion...
Boundary Conditions of Tidal Model at River Mouth
A small grid is required to schematize irregular shape of shoreline in the vicinity of river mouth which limits the modeling area to be small. Tidal records along the boundary show no...
Sorting of Mixed Sand on a Two-Dimensional Beach
A numerical method is developed to predict temporal variations of the sea bed topography and the bed-material composition. The predicted results are compared with the measurements in a...
Cellular Automaton Simulation of Viscous Free Surface Fluid Dynamics
It has been demonstrated elsewhere that the simple interaction of a two dimensional field of discrete particles traveling on a regular lattice yields large scale behavior closely approximating...
Verification of Local Modes in a Two-Dimensional Tidal Model
Based on a generalized model equation, a two-dimensional hybrid finite element model has been developed to study tidal waves of incompressible, homogeneous fluid in rotational flows. In...
Risk-Cost Principles for Dam Safety Analysis
The purpose of this paper is to present the principles and issues of risk-cost analysis as they have evolved in the evaluation of dam safety improvements. The paper also reviews some results...
Global Climate Change?Implications for Large Water Resource Systems
Prospects of global climatic change resulting from the greenhouse effect are causing increasing concern. Predicted increases in average global temperatures are likely to be accompanied...
Issues of Detectability of Climate Change Impacts on the Runoff of a Southeastern River Basin
Can we detect and predict changes in hydrology caused by climate changes? Assuming credible predictions of climate change, can we predict corresponding hydrologic effects? Are uncertainties...
Climate Change Effects on Great Lakes Levels
The Great Lakes Environmental Research Laboratory has developed conceptual models for simulating moisture storages in and runoff from the 121 watersheds draining into the Laurentian Great...
Climate Change and U.S. Water Resources: Results from a Study by the American Association for Advancement of Science
The time horizon of the changes that might occur is similar to the time required for planning, approval, funding, construction and economic life of such major water facilities as dams,...
Design of Expansions for Sub-Critical Open Channel Flow
Expansions for open channel flow at sub-critical velocity are required whenever it is necessary to reduce the velocity of flow from a structure which discharges into an erodible channel....
Lower Santa Ana River Hydraulic Design for Levee Overtopping
The purpose of overtopping or freeboard design is to minimize damages and catastrophic failure from floodwaters overtopping levees. This case study is presented to show the approach taken...
Vessel Induced Physical Effects in a Navigation Channel
The U.S. Army Corps of Engineers is investigating ways to improve lockage efficiency at the Marmet Locks on the Kanawha River, West Virginia. A physical effects prediction model have been...
International Research on Mechanics of River Bank Erosion?A Summary Overview
A brief overview is presented of research regarding mechanisms of river bank erosion and treatments. In the research river planforms, water stages, currents, waves, ice sediments, bed...
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