maybe it's a good idea to take part of a map to take as a start? this would make it look 'real', i think.
from your massing model i think a piece of amsterdam or london would be great because they are old towns. no matter what is built there, the ground and water parties will be the same as they were for ages. rotterdam, hamburg, bremen or antwerp are not so good i think because the harbours there are either much more recent or just lying along the river without canals.

"The light at the end of the tunnel may be an oncoming train"