Make it so swamps, or parts of swamps can be traveled by (small) boat. Where rivers cut through swamps, boats can go from one to the other.
Boardwalk can be built on swamps to allow the movement of carts and the placement of buildings. Boardwalk can decay back into swamp, or can be removed with a landscaping action. Boardwalk under buildings doesn't decay until the building is destroyed (by decay or otherwise).
New plants and animals that live in swamps would also make the area more interesting, and worth exploring.
- Animal ideas: snakes, alligators/crocodiles, ducks, turtles
Plant ideas: mangrove, lotus, reeds/cattails
