plunge basin

plunge basin

[′plənj ‚bās·ən]
(geology)
A deep, large hollow or cavity scoured in the bed of a stream at the foot of a waterfall or cataract by the force and eddying effect of the falling water.
References in periodicals archive ?
Clark Reservation State Park visitors can see rugged cliffs and meadows as well as a glacial plunge basin lake.