[bourgoin]

I have a hard time conceiving of any reason that North and South would be different in this regard, but maybe it's possible if there is a tendency for rivers to flow towards the equator for some reason, since most of the world's landmass happens to be in the northern hemisphere.

[darkerside]

Perhaps on some level, since melting ice would follow away from the ice mass. But AFAIK, there is no causative reason for rivers to flow towards the equator. A quick Google search corroborates this.