Both physical and numerical models can be used to analyze some of the factors that will affect the safety and effiency of the projects. However, because of the complexity of currents and the effects of wind, waves, tides and sediment movement, the hybrid modeling approach (which uses both physical and numerical models) is usually required to obtain an accurate evaluation of the conditions that can be expected with each plan and modification considered, particularly in estuarine areas.

Physical scale models are used to investigate flow patterns when complicated three-dimensional (3D) effects are necessary. Recent dramatic advances in computer hardware and software have led to the use of numerical models to replace and supplement physical model studies. The following types of navigation investigations can be conducted with physical models:

• Shoaling and erosion characteristics;
• Salinity intrusion;
• Wave penetration and harbor response;
• Jetty design and armor stability;
• Ship response to waves;
• Channel width in critical navigation reaches;
• Tide heights and current patterns;
• Navigation conditions.