5. There is, therefore, a gap between the requirements to perform 

 sophisticated inlet hydrodynamics modeling and the needs, knowledge base, and 

 computer resources of the project -level planner and engineer. The development 

 and verification of a simple, yet accurate model of inlet hydrodynamics for 

 use in reconnaissance -level quantitative studies of inlets at the project 

 level are identified as a research need to be addressed. 



6. The research conducted in this study was directed toward answering 

 the question of whether it would be possible to develop an accurate and easy- 

 to-use numerical model suited for operating with computer resources available 

 in any engineering office, namely a modern desk- top or personal computer. The 

 model should be suitable for reconnaissance -level studies for most inlets by 

 providing reliable and accurate answers to users who do not have experience in 

 numerical modeling, facilitating minimal data entry and numerical grid- 

 generation. 



7. The objective of this study was, therefore, development of a state- 

 of-the-art reconnaissance-level model for predicting tide -dominated velocities 

 and water level fluctuations at an inlet and verification of the model by 

 comparison to field measurements. The model would have a rigorous theoretical 

 foundation, be numerically implemented in a sound manner, and be capable of 

 describing realistic situations. It should provide detailed velocity informa- 

 tion across the inlet channels, be able to describe multichannel inlets, be 

 flexible to allow inclusion of new features, and importantly, be easy to 

 operate on a personal computer. 



8. This report describes a numerical model developed to satisfy the 

 above requirements. The model is based on the full one -dimensional shallow- 

 water equations employing an implicit finite -difference technique. The model 

 was named DYNLETl, reflecting the fact that it is a one -dimensional model of 

 the dynamic (time -dependent) behavior of the tidal flow at inlets. It is 

 asserted that use of the full one -dimensional hydrodynamic equations and a 

 rigorous treatment of the cross -sectional inlet and flow properties meet the 

 objective of this study. 



9. The principal limitation of DYNLETl is potential inaccuracy in 

 situations where strong two-dimensional flow fields, such as gyres, exist 

 perpendicular to the major axis of channels comprising the modeled inlet. 

 However, the model is well suited for applications to narrow inlets connected 



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