 This floodplain was characterized by a series of swells (natural levees created by river deposits) and swales (ancient river channels and tributary channels).The Eva site was situated on a high swell between a swale known as Three Mile Slough to the east and a swale known as the Cypress Creek Slough to the west.In Archaic times, the Tennessee River proper flowed through Three Mile Slough (roughly a mile west of its modern pre-inundation channel).