- Mobile Bay is a shallow, micro-tidal estuary in the northern Gulf of Mexico. The Bay receives the 4 th largest river discharge in the continental United States of America. The large river discharge results in strong water column stratification not only inside the Bay but on the inner shelf adjoining the Bay. This paper presents two cases that highlight the importance of stratification in the tidal Mobile Bay system on: (1) vertical mixing in the shallow inner portion of the Bay and (2) salt exchange with the Gulf through the Bay mouth. 2012 IEEE.