"Seventy percent of the country's rivers are at low levels," says Grzegorz Walijewski, hydrologist at the Polish Meteorological Institute, who warns that rising temperatures are causing "hydrological drought". Speaking to AFP in Warsaw, Walijewski explains that the Vistula river is nearing the record low level seen in 2015. "The record will probably be matched this weekend and then beaten." IMAGES AND SOUNDBITES