Should it flood, the boar would hane no trouble swimming out.        
Wild boar are good swimmers and one individual wild boar has been reported as having swum across a 700m wide river. Wild boar can range long distances and one animal has been known in Kampinos National Park, Poland to move over 250km. Long distance dispersal may be related to the type of landscape, population density and hunting pressures. The density of wild boar in Europe is usually below five individuals per km2. Still higher densities of wild boar can occur when supplementary feed is given: 10 animals per km2 have been recorded in a Polish forest.
In eastern Europe, wild boar fall prey to lynx and wolves. However, lynx will preferentially hunt red deer Cervus elaphus and roe deer Capreolus capreolus rather than wild boar, which are more aggressive and frequently found in large groups. Wolves, in the Bialowieza Primeval Forest in Poland, also preferentially took roe deer rather than wild boar. Wild boar are, except in a few locations, generally avoided by wolves. Wild boar also benefit from the presence of lynx because they feed on ungulate carcasses left from a lynx kill. They are even able to commandeer a fresh kill from a lynx.
In Brtitain, the only predator of wild boar is man.