One of the most important, dirty and labor intensive aspects of terrestrial archaeology is screening excavated sediments: as above, so below. Well, sort of. Working underwater makes everything more complicated.

Although archaeologists dig very carefully, they often screen excavated material to make sure no important clues are missed. On land, this is most often accomplished by filling buckets with back dirt and dumping them through a 1/4″ or 1/8″ screen. The archaeologist shakes the screen and the dirt sifts though, leaving artifacts behind.

While the principle is the same for underwater sites, the logistics are nightmarish.

On the Aucilla River Project, we pumped fill directly to the surface, where it was screened on a floating barge (see a description here). This was practical because we were mostly working with fine sediment, and the current mostly carried back dirt away from the site. We rarely clogged the dredge, but when we…