Para los ríos, no se como funciona, porqué aún no lo he probado, pero a simple vista deberias descomentar alguna de estas líneas (quitar el símbolo # del principio):
# now river stuff
# first river type (should be defined in pak dependent file)
# The highest number is the smallest. A river with max_speed==0 is not navigavable by ships.
#river_type[0] = river
#river_type[1] = small_river
#river_type[2] = just_the source
# river number (16 gives a few nicely branched rivers)
#river_number = 16
# min length
#river_min_length = 16
# max length
#river_max_length = 320
Puedes probar con esto:
# now river stuff
# first river type (should be defined in pak dependent file)
# The highest number is the smallest. A river with max_speed==0 is not navigavable by ships.
river_type[0] = river
river_type[1] = small_river
river_type[2] = just_the source
# river number (16 gives a few nicely branched rivers)
river_number = 16
# min length
river_min_length = 16
# max length
river_max_length = 320
Ya me contarás si te funcionó.