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For advectiondominated transport processes, the traditional numerical techniques for solving the advectiondiffusion equation fail because of numerical oscillations. Fractional step solutions, in which the advection and diffusion processes are treated in separate steps, have been proposed as one way of overcoming this problem. Here a solution to the advection step based on the method of characteristics on a fixed grid is used. Interpolation is achieved with the finite element technique. Linear and quadratic elements are evaluated in terms of artificial diffusion, phase, and other errors. It was found that linear interpolation creates too much numerical diffusion, while the quadratic scheme is reasonably accurate, but under certain conditions generates spurious extrema. A method retaining the accuracy of the quadratic interpolation and eliminating its shortcoming is suggested. Boundary conditions and source loadings are considered in detail. An application of the model to salinity distribution resulting from canal discharges in Biscayne Bay is described.

The essentials of hydrodynamic model application techniques and necessary supporting data are given for the situation of a partially stratified water body. The presentation is aimed at improving numerical predictions of tidal hydrodynamics, and is oriented toward somewhat experienced modelers. So as to guide the modeler, the subjects covered are arranged in the order in which they ideally would be addressed during the execution of a study. These subjects fall broadly under the headings hydrodynamic classification, model selection, model adaptation, model testing and calibration, and model verification and application. Meaningful and quantitative measures are needed to establish model performance, and to provide a basis for model intercomparisons and possible future setting of standards. Various quantitative measures are suggested. To encourage their use, it is recommended that providing a quantitative measure when comparing model data with observed data be a condition for publication. A number of research needs are also identified.

Program ROUTWEIR represents a twodimensional flood routing model designed to analyze twodimensional flow caused by rainfall and runoff flooding events. Input to the program consists of known geometry, topography, initial conditions, and boundary conditions. The geometry and bathymetry of the flood plain are represented by a grid of interconnecting triangular elements. Initial water levels are prescribed to correspond to the normal water elevations in the river channel. Boundary conditions are prescribed by a discharge hydrograph at the upstream boundary of the river basin, and by the water surface elevations at the ocean boundary. The interior water elevations and discharges are computed, allowing flooding and drying to take place in the triangular elements of the grid, based on a conservation of water volume equation and a surface slope dependent dynamic equation. Output consists of time histories of water surface elevations and peak elevations in both tabular and graphical form. ROUTWEIR has been successfully calibrated against recorded flood levels in the Rio Culebrinas Basin in Puerto Rico and has been used in that basin in a federal flood insurance study. A versatile computer program, ROUTWEIR can be applied to many flood routing problems. It is particularly suited for wide river basins with large bottom slopes and for normally dry areas subject to extensive flooding.

A numerical solution to periodic nonlinear irrotational surface gravity waves on a horizontal sea floor is developed using an iterative Boundary Integral Equation Method (BIEM). This solution technique is subsequently applied to determine the characteristics of limit waves for which the wave crest theoretically ceases to be rounded and become angled with an included angle of 120°. The analysis includes waves with and without mean currents and can also be used to estimate the wave set‐down. Solutions with zero mean current are parameterized as functions of relative water depth and presented in graphs. In the cases with current, the results are given in terms of the relative water depth and a dimensionless current speed.

The hydrodynamic exchange in this barrier island lagoon that has been highly modified by dredging and causeway construction is analyzed using field measurements and numerical models. Based on the field observations, a nested numerical modeling approach is adapted to determine the tidal and winddriven flow and circulation. The nesting of one‐ and two‐dimensional models provides an efficient solution method without sacrificing predictive ability or resolution. Alternatives for enhancing hydrodynamic transport and circulation by modifying the geometry of the bay are evaluated and residence times for present conditions are determined.

The use of synoptic atlases of wave climatologies for determining shore line evolution is examined critically. It is concluded that the fineness of discretization of wave height is not too important, as long as energy is conserved, but a fine discretization of wave angle is needed. Due to importance of order of sequential wave events or time history of the wave input, a Monte Carlo simulation of the wave climatology is proposed to determine shore line location probabilistically instead of deterministically.

Program ROUTWEIR represents a two‐dimensional flood routing model designed to analyze two‐dimensional flow caused by rainfall and runoff flooding events. Input to the program consists of known geometry, topography, initial conditions, and boundary conditions. The geometry and bathymetry of the flood plain are represented by a grid of interconnecting triangular elements. Initial water levels are prescribed to correspond to the normal water elevations in the river channel. Boundary conditions are prescribed by a discharge hydrograph at the upstream boundary of the river basin, and by the water surface elevations at the ocean boundary. The interior water elevations and discharges are computed, allowing flooding and drying to take place in the triangular elements of the grid, based on a conservation of water volume equation and a surface slope dependent dynamic equation. Output consists of time histories of water surface elevations and peak elevations in both tabular and graphical form. ROUTWEIR has been successfully calibrated against recorded flood levels in the Rio Culebrinas Basin in Puerto Rico and has been used in that basin in a federal flood insurance study. A versatile computer program, ROUTWEIR can be applied to many flood routing problems. It is particularly suited for wide river basins with large bottom slopes and for normally dry areas subject to extensive flooding.