why do rivers flow north to south

Yes but let's just say it is downhill for the first third of the river then straight for the next third and uphill for the final third, by that logic there would be no net flow at all -it would just pool in the middle third.

I thought something similar though -which is that the water flowed in a direction that minimised the pressure behind it. That of course can be based on the geography of the exact area (hilliness and all), but more importantly it would be the amount of water.

And since there is more water at the poles, there would be a general trend to flow away from them ie southwards in the northern hemisphere and northwards in the southern hemisphere.

I do realise there are some serious flaws in this suggestion,though. My co-debater suggested that water flow was somehow determined by differece in the earth's magnetic field but I think that sounds like total nonsense.

More commentaries please.
It disturbs me how often I m asked why x river flows northward or for the name of three rivers that flow north. Most of these questions come from Americans who, for some reason, must presume that since the Mississippi flows south, all rivers on the planet flow south.

Thus, to hopefully educate the world about the goals and desires of rivers, I ve written a new article called,. Cheers!