Preposition: of

• water: His eyes were open, blind, and runnels of muddy water streaked his face like tears.

Converse of object

• climb: Start on a flat boulder at the base of the slab, step left off this and climb a shallow runnel to a ledge.

Adjective modifier

• shallow: Start on a flat boulder at the base of the slab, step left off this and climb a shallow runnel to a ledge.

• obvious: Start 2 meters right of the amphitheater at the foot of the obvious green runnel.

Noun used with modifier

• ice: Starts up a steep and narrow ice runnel to gain easier ground and the final section of King's Ransom.