Determining where the sea-levels were located over the last 20,000 years is and central to where we might look for submerged pre-contact sites. Identifying sea-level depths has a two-fold benefit. We know that people do not live underwater. If we are looking for archaeological sites of particular cultural group, we know that once the oceans had transgressed an area, no one was living there after that period.
The second benefit to knowing the depth of sea-levels is how it affects freshwater tables. Salt water is much denser than freshwater. As sea-levels rise,salt water pushes freshwater tables upward on land. Many of Florida’s famous fresh water springs were just caves before sea-levels had increase to modern levels. Many of Florida’s major rivers like the Wakulla, Ichetucknee, Suwannee were just a series of caves and sinkholes until oceans waters forced the Floridan aquifer to the surface. Identifying where freshwater sources were during times of lower sea-levels helps us identify where archaeological sites might be.
For an in-depth dive into Sea-level modeling: JQI_Joy S. 2019 The Trouble with The Curve_Reevaluating the Gulf of Mexico Sea level Cruve