effect of water on wall

[forever changes]

i'm thinking of buying a house but wary because the lowest section of the gable wall [although several feet below cellar level] doubles as the side of a canal ie it has been submerged in water for 130 years. God knows how it was built as the canal was there first, but does anyone know what problems may arise or where to find advice?

 

[patan]

Was it not meant to be submerged?Is there any visible damage?
One of the hazard would be when an unusual amount of rain could flood the space.