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This study conceptualized the groundwater flow system; estimate the distribution of hydraulic conductivity and groundwater recharge in the lower Pra Basin in Ghana using the Groundwater Modeling System (GMS). It gives a detailed description of the site which consists of the Geographical, Hydrogeological and aquifer Characteristics of the region. The model was built by first developing a conceptual model which describes the hydrogeological framework, distribution of spatial and temporal boundary conditions, groundwater sources and sinks. This conceptual model was further converted to a numerical model for the flow simulation. Model calibration and sensitivity analysis were performed on the numerical model by comparing the observed hydraulic head with the simulated hydraulic head during calibration while model parameters were varied to obtain the most sensitive parameters in the model. The model performance was estimated to give RMSE = 3.32, R2 = 0.99 and ME = 0.07. This gives a high model performance for the study area.

Ekman's linear equations for time dependent flow (neglecting wind stress) are solved using a time dependent Green's function and the method suggested by Welander (1957). The solution represents the vertical velocity profile in terms of the local time history of the changes in sea surface elevation determined by the divergence of the flow in the vertically integrated continuity equation. A fully implicit finite-difference scheme is developed to represent a time dependent seiche oscillating across a shallow infinite channel. The transients associated with the formation of the bottom spiral are clearly represented by the model and the influence of friction and Coriolis are individually and collectively introduced. The model allows independent calculation of velocity, volume transport, sea surface elevation, bottom stress, and the total energy balance of the system. The numerical scheme provides a method for adequately describing and investigating certain classes o time dependent action, and its development suggests a mechanism for improving numerical prediction of storm surge. http://archive.org/details/aninvestigationo1094516207 Lieutenant Commander, United States Navy Approved for public release; distribution is unlimited.

Source: https://erdc-library.erdc.dren.mil/jspui/ The large first cost and subsequent operation and maintenance costs of sea-level canals demand that all economic and technical alternatives be thoroughly investigated before construction is begun. The vast number of variables to be considered for any given set of alternative canals requires study in an orderly and meaningful manner. An analytical model in the form of a digital computer program to predict ship transit capacities of sea-level canals has been written and tested. The program calculates ship movements by evaluating, at small, equal time increments, the many changing factors which affect their movement. In addition to inserting ships into the canal in some prescribed order, the program keeps track of each ship (its type, location, speed, and direction) in the canal and adjusts its speed at each time increment so that each ship operates safely under a predetermined set of conditions. The program is designed to predict the number of ship transits per unit time by considering the canal configuration, flow conditions in the canal, and the shipping which is expected to use the canal. The program can be used to optimize canal configuration for any given expected shipping, to optimize the manner of ship input for a given canal configuration, and to develop operation pr ocedures for any canal configuration with any ship mix. Future versions of the program can be used to control actual canal traffic in a real-time configuration. The model has been made as general as possible, lacking generality only where present knowledge does not allow sufficient definition of variables and processes. Some simplifications have also been made for the sake of expedience because of the time limitations of the study. Because of its modular form the program can be changed to incorporate future developments with relative ease.

The Hansen Hydrodynamical - Numerical model was evaluated for Monterey Bay with actual field data. Tides and winds are the principal driving forces of the Hansen model. Analysis of the field data indicated that the principal driving force of the circulation in the bay was the oceanic currents and not the tides and winds. The tidal heights and phases and current directions were calculated correctly by the model, but the calculated current speeds were an order of magnitude too large. The inaccuracy of the current speeds was attributed to the inaccurate calculations of the currents along the open boundary and the large bathymetric gradients of the Monterey Submarine Canyon. http://archive.org/details/anevaluationofnu1094515701 Approved for public release; distribution is unlimited.