By elevation of the atmosphere
Answer:
Unless the land it totally flat, rivers of water run downhill. ... If the source of a river is at a higher elevation than the mouth, that river will run from the source to the mouth. However, if that (higher) source is to the south of the mouth, that river will then flow to the north (downhill).
MAPS ARE CONSTANTLY ADAPTING TO THE INFLUENCE OF WEATHER AND OTHER ISSUES
