A closed conduit of rectangular cross section used to pass floodwaters under a highway or railroad
A culvert with a square or rectangular cross-sectional profile having 4 sides, including a bottom Sometimes a 3-sided culvert with an open bottom is considered a Box Culvert, however in this Wildlife Crossings Toolkit these are referred to as Bottomless Culverts Made of precast concrete, cast-in-place concrete, corrugated metal, metal plate and wood See Bottomless Culvert