In Preferences there is an option to select the effect of the flow of a river on your selected speed. But it's not clear whether the default speed is for upstream or downstream. So if I select a speed of say, 4.5 mph with a flow effect of 1 mph, does that mean 4.5 mph upstream and 5.5 mph downstream? Or 4.5 mph downstream and 3.5 mph upstream?
the speed is applied in both directions.
So a base of 4 with a flow of 1 means 5 down and 3 up.