Significant tributaries include the Ela River, the Mad River, and the Isinglass River.

Entity and relation annotations:
id: 0
type: entity
value: text: the Ela River
labels: <Location>
id: 1
type: entity
value: text: the Mad River
labels: <Location>
id: 2
type: entity
value: text: the Isinglass River
labels: <Location>