There are 5 bigger rivers and many small streams and rivulets. The oldest part is located mainly on river isles:
http://bi.gazeta.pl/im/8/7918/z7918398X.jpg

There was already a huge flood in 1997:
http://upload.wikimedia.org/wi.....odz_wr.jpg

About 1/3 of the city was under water:
http://huby.seo.pl/09_woda/img/powodz1997.gif

Looks like the same thing is going to happen now. The walls and levees are broken and water is already there:
http://wroclaw.gazeta.pl/wrocl.....7.html?i=0

I live quite far from the nearest river, so I'm safe (although the walls in my basement are wet). However, the situation is not good. Two huge floods in 13 years...