inverted siphon

An inverted siphon is a pipe used to transport water or other liquids beneath a depressed area, such as a stream or a road cut. Unlike a standard siphon, which relies on gravity and liquid cohesion to move fluid over an edge, an inverted siphon operates under pressure, with the liquid completely filling the pipe. This design is commonly employed in civil engineering for managing sewage or stormwater flow across natural or man-made depressions. At sea level, a standard siphon can lift water up to approximately 10 meters (33 feet) due to gravity and the liquid's cohesive properties.12