Culverts are the structures that carry streams and dry stream beds safely beneath the road body where they cross the route. An undersized culvert leads to scour of the road body in wet periods and closure of the section to traffic.
Box, pipe or arch culverts are designed according to hydraulic calculations. Construction uses in-situ reinforced concrete or precast units; wing walls and scour protection stone fill are formed at the inlet and outlet.
Ditch lining works cover the protection of roadside collection ditches against erosion by lining them with concrete or stone.
