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TWO procedures were developed to simulate salinity intrusion in the Mississippi River. The first one is based on the arrested salinity wedge theory and is applicable to quasi‐steady‐state flow conditions. It simulated very well the experimental results of Keulegan. It also simulated the positions of salt wedge tips and their interfaces in the Mississippi River with proper adjustment of the interfacial friction factor. The second one is a steady‐dynamic routing model, which routes salt water in a cascade of reservoirs in the river bottom. Densimetric critical flow is assumed over a reservoir ridge. Error in storage definition is included in a calibration coefficient for the saltwater flow computations over the reservoir ridges. The model satisfactorily simulated durations of salt wedge presence along the lower Mississippi for the existing conditions and after deepening the channel to 55 ft.

Numerical analyses made with the use of Program FAT, previously developed in collaboration by the senior writer, with the Program LATIS, on the propagation of the transient flow subsequent to a dam failure, are presented. The main difference between the new and old programs consists in the formulation of the continuity equation, which in Program LATIS is written for the node instead of the link. This allows the analysis of more complex networks, presently under study. The hypothetical gradual collapse of the cofferdam of the Bou Regreg Dam in Morocco was studied to assist in the preparation of emergency plans. These results are compared to those of an instantaneous collapse of the same project and of a dam in a rectangular channel.

A numerical model is developed to predict the shoreline changes at Nome, Alaska due to the construction of a causeway that will connect the offshore port terminal with the onshore facilities. The model is based on a procedure developed earlier by other researchers. Several aspects of the original procedure are elaborated and modified. The resultant model was verified by simulating the present beach condition near the entrance jetties of Nome Harbor. Using the same parameters, the model was applied to the causeway and shore configurations for a 30‐yr period were predicted. These applications show that the modifications made on the original model are promising. The model can be applied to other similar situations provided the parameters are calibrated by simulating existing conditions.