More than 19,000 people have been evacuated from the flooding that has affected half of the Czech Republic, said firefighters spokeswoman Nicole Zaoralova.
Some 3,000 people had to leave their homes in Usti nad Labem on the Elbe river near the German border where the waters were still on the rise Wednesday. High waters have already submerged parts of the city as well many other towns along the Elbe, the biggest river in the country.
They are also threatening major chemical factories, including one that released toxic chemicals into the Elbe during the devastating floods of 2002. The plants have been shut down as a precaution and chemicals removed, authorities said.
Czech public television said a barrier that protects one chemical plant in Lovosice was leaking Wednesday and it was not immediately clear if it might be completely flooded.
Rising river levels threatened vast parts of eastern and southern Germany and hundreds of people were being evacuated in the city of Dresden.
On Wednesday morning, the Elbe stood at 8.3 meters (27 feet) in Dresden, compared with its normal level of 2 meters (6 1/2 feet). Authorities were expecting the crest of the flood to hit the city in the eastern state of Saxony in the evening.
In the eastern city of Halle, the downtown area was already flooded. Elsewhere in the affected regions, soldiers and residents were reinforcing soaked levees with sand bags to keep them from breaking.
The water was slowly receding in the hard-hit Bavarian city of Passau, leaving behind vast amounts of debris.
In the Czech capital, the level of the Vltava river continued dropping as authorities surveyed the damage.
Prague's Zoo was particularly badly hit for a second time in 11 years. This year's spike in water levels has been far less than in 2002 but the zoo estimated the damage at $8 million as major reconstruction will be needed once again.
The lower side of the park was submerged and animals had to be evacuated. The zoo announced it would reopen the higher parts to the public on Wednesday. "The flood will not break us," it said in a statement.
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