The submerged remains of two settlements have been located at Powidz and Polanowo in Poland.
The site at Polanowo survives as a dense concentration of pine and birch piles in one-two metres of water, some 76 metres north of the coast. Similarly, a large assemblage of birch piles survives at the Powidz site under 1-2 metres of water on the edge of a shallow shelf, which then plunges down from 2-20 metres.
The site at Powidz is located on a stretch of lake-shore which is extremely popular with tourists due to the recent construction of a pier and the dumping of sand by the lake-shore to create a beach effect. As a result the site is under constant threat from swimmers, wind-surfers, and boat owners; as the site sits in shallow water just to the right of the pier. It has been damaged by people walking over, while the most devastating damage has been caused by boats that are dragged over the site to the shore or to the pier. This relatively recent activity may account for the small number of piles recorded at Powidz when compared to Polanowo.
Over one thousand ceramics were recovered from the two sites and all suggest a date sometime during the transition from the Late Bronze to the Iron Age (from the 8th to the 6th century BC). This date has been confirmed by the radiocarbon determination of structural timbers from both sites.
The importance of the Powidz and Polanowo sites is enhanced by the fact that they lie within 50 kilometres of the famous Late Bronze Age fortified stockade of Biskupin.
The team surveyed 570 timbers at the Polanowo site, covering an area extending 35 metres north-south by 53 metres west-east. At Powidz, the team surveyed 87 birch piles covering an area of 26.5 metres north-south by 15 metres west-east.
The sites have been surveyed in detail using a Total Station equipped with Pen Map for Windows data logging software. This software, unlike other logging and processing software, is used on a pen-based portable computer, plugged directly into the Total Station. This is particularly advantageous for underwater survey, as the spread of points being taken on a site can be viewed in real time as they are being taken. The use of this software allowed the production of accurate three-dimensional digital plans of each submerged site.
It seems likely that both Powidz and Polanowo settlements were originally lakeside dwellings that became submerged after the 6th century BC. This would tie in with evidence from Biskupin, where changes in climate after 700 BC led to a rise in the groundwater level of two metres, which ultimately led to the abandonment of the sites after 500 BC.