River

A river is a route, and on a world without a road network it is the only route that goes anywhere. It is also the one piece of terrain that moves: everything in it is carried downstream, including a party that loses its footing. Settlements stand on rivers, so a party traveling by river passes them whether it wants to or not.

Regional environment Aquatic (water)

Tropical Dry Temperate Continental Polar

Lowland Highland

Crossing it

Navigate: DC 5
Forage: DC 10
Notice: DC 10

Downstream doubles the day. Upstream halves it.

In play

The current

A creature in the channel is carried 1d4 x 10 feet downstream at the end of its turn unless it is anchored or swimming against it at half speed.
Route

Travel downstream doubles the day's distance and ignores difficult terrain. Upstream halves it.
Crossings

A pursuer knows where a party can cross, because crossings are few. A ford or a bridge is a likely ambush site.
Flood

After heavy rain upstream, the channel rises 1d6 feet an hour for 1d4 hours and the ford is gone.

Variations

Headwater

Steep, fast and cold. Vessels portage around obstacles, and no vessel larger than a boat can use it.
Lowland channel

Slow, wide and navigable. Traffic, tolls and a settlement at every confluence.
Delta

The channel splits into a hundred branches. Navigation is DC 15, and the route differs each season.

Worlds it occurs on

Terran (Arid) A hot, dry rocky world habitable at its edges, with dune seas across the interior.
Terran (Verdant) A rocky world with liquid water, breathable air and a magnetic field to protect them, rare and the cause of most wars.