Slitherine

I don't see the small rivers on the map. I guess it's because I have a pigmentation defect in my eyes that makes me not distinguish certain colors. Can all rivers on the map be changed color? Does anyone know how? Precise instructions, please, I have no idea about mods.
THANK YOU

They are very discreet, whatever the color used, there is not much improvement to be done here, until the next game that is!

Okey, thanks.