How? There is absolutley no nav in that canal.
#Juggernaut attempt to swim
sterile magnet
hardy tide
Also if infected make a nest close to the ledge they will just run of it and die. (also as op. you can fall off since the concrete fence things are just decorative)
sterile magnet
Found the problem, collision settings on that edge wall were set wrong. Correcting that SHOULD also prevent infected from building too close to the edge....but we shall see.