Salinity currents within Mobile Bay are potential paths by which oil-related substances enter and spread, harming natural ecosystems. The average depth of Mobile Bay is very small, ranging between 3 and 4 meters, except at the shipping canal where the maintained depth is around 14 m. This navigation canal is about 50 km in a north-south direction and spans the mouth of Mobile River and the bay entrance, with an average width of about 130 meters. Along the length of the canal there is a strong stratification between the saltier water from the Gulf of Mexico and Mobile river fresh water.
Field measurements indicate that the stratification layer separating the fresher water from the bay and the saltier ocean water is generally contained within the ship canal cross section. It is thus reasonable to assume that the canal is a preferential path by which oil-related substances present in the water column in the Gulf of Mexico will enter Mobile Bay, and then harm local biological systems. In this process, the understanding of the mixing processes that occur within the ship canal and nearby shallower zones for different flow conditions is an important step t better assess the potential impacts of oil contamination through the canal. Such findings may be particularly useful in the modeling of the contamination dispersion processes, using tools such as the Environmental Fluid Dynamics Code – EFDC.