Photo Tomasz Gzell
Archaeologists in the capital have been quick to take advantage of the situation, and a large number of relics have already been transported to a storage depot.
It is believed that the treasures ended up underwater owing to the so-called Deluge of 1655-60 (Potop), the Swedish invasion that saw Poland brought to its knees and stripped of much of its material wealth.
The invaders shipped their booty up the River Vistula to Gdansk, from where it was transported by sea to Sweden.
However, not all of the vessels were successful in getting their weighty cargo as far as Gdansk.
Archaeologists have in fact been sporadically engaged in searching the river for such treasures since a special project was launched in 2008.
However, owing to this week's record lows, state-of-the-art scanning gadgetry was unnecessary.
Tests on the water levels of the Vistula in Warsaw have been carried out since 1799. This week, the level reached just 60 cm, the lowest since checks began.
Hydrologists have nevertheless stressed that Warsaw residents have no cause for alarm as regards water that is processed for the domestic use.