wadi (n.)
- abysm
 - abyss
 - aqueduct
 - arroyo
 - beck
 - bed
 - bottom
 - bottoms
 - bourn
 - branch
 - breach
 - break
 - brook
 - brooklet
 - burn
 - canal
 - canyon
 - cavity
 - channel
 - chap
 - chasm
 - check
 - chimney
 - chink
 - cleft
 - col
 - crack
 - cranny
 - creek
 - crevasse
 - crevice
 - crick
 - culvert
 - cut
 - cwm
 - dale
 - defile
 - dell
 - dike
 - dingle
 - ditch
 - draw
 - excavation
 - fault
 - fissure
 - flaw
 - flume
 - fracture
 - freshet
 - furrow
 - gap
 - gape
 - gash
 - gill
 - glen
 - gorge
 - groove
 - grove
 - gulch
 - gulf
 - gully
 - headrace
 - hole
 - incision
 - joint
 - kill
 - leak
 - midstream
 - moat
 - notch
 - nullah
 - opening
 - pass
 - passage
 - race
 - ravine
 - rent
 - rift
 - rime
 - river
 - rivulet
 - run
 - rundle
 - runnel
 - rupture
 - scissure
 - seam
 - slit
 - slot
 - sluice
 - spillway
 - split
 - stream
 - streamlet
 - swash
 - tailrace
 - trench
 - trough
 - vale
 - valley
 - void
 - watercourse
 - waterway
 - waterworks