a deep opening or crack in the ground

gap, abyss

a deep, narrow opening, usually with a stream, between hills or mountains

valley

a deep, narrow valley

gap in earth's surface

an apparatus for regulating the level of water by controlling the flow into or out of a canal, lake etc; a channel for water

stream

a kind of long, open box used for animals to feed or drink from; a region of lower atmospheric pressure between two regions of higher pressure

gutter, depression