The impact of sea level rise on maritime navigation within a large, channelized estuary

Vessel handling guidelines in Tampa Bay have been developed and refined over many years to prevent vessel groundings, collisions, and other maritime incidents. These guidelines restrict navigation based upon vessel characteristics such as vessel length, draft, displacement, and destination, often in conjunction with tidal levels and current speeds. A numerical circulation model of the Tampa Bay estuary was used to examine the occurrence frequency of the most common limiting current speeds within the main shipping channel under four sea level rise (SLR) scenarios ranging from 0.25 to 2 m. Near the bay mouth, the occurrence of limiting speeds generally decreased with SLR, but farther up the channel it increased, mostly due to changes in the M2 tide, with contributions from other primary tides. The relative occurrence of slack water, the lowest of the limiting speeds, was most sensitive to SLR, with absolute changes in occurrence ~50%. Higher speed limits had smaller relative changes. A methodology is developed using data from the Automatic Identification System that identifies vessel traffic potentially impacted by SLR and changing tidal currents. Some implications of reduced tidal currents for port and vessel traffic management are discussed.