Travel times over terrain

Just curious, hills decrease travel time by 25%, mountains by 50% both perfectly reasonable as an army would be slower going up hill. The puzzling bit for me is, rivers and lakes decrease travel time by 50%, ok I guess if the army is on foot, but if they are in brigs, you would surely think that the travel time would be quicker, not slower?

If this is intended behaviour and not a bug, then why do brigs prefer going on a river with a 50% penalty, when they could just go next to it over steppe without penalty?

Would be very interested to hear what people and the devs think:)

Yes it would be logical, if rivers and lakes increase travel time of land units by 50% (army by foot), but would decrease travel time of naval units by 50% (army on rafts or brigs).

"If this is intended behaviour and not a bug, then why do brigs prefer going on a river with a 50% penalty, when they could just go next to it over steppe without penalty?" - Brigs have a bit faster speed compared to most of the land units, so even with "penalty" - they are crossing such tile faster. In new update there will be revorked a bit penalty to boarding/unloading onto ships (water border crossing). Also will be fixed bug with "wandering armies" in awareness zone.