Gifu · JP
Kagami Yōsui Yamada-gawa Inverted Siphon (Kagami Canal Yamada River Siphon)
The Kagami Yōsui Yamada-gawa Inverted Siphon (各務用水山田川サイホン) is a piece of working irrigation infrastructure in the Akutami district of Gifu city, where the Kagami canal carries farmland water beneath the Yamada River instead of across it. It is the kind of place that rewards the curious traveller, the canal enthusiast or the reader interested in how rice paddies on a dry plateau are fed from a river many kilometres away. This siphon is one structure in the 各務用水 (Kagmi irrigation canal), a waterway that draws its supply from the Nagara River in Seki and threads through the western Seki hills and north-eastern Gifu before reaching the farmland of the Kagami plateau. Rather than bridging every tributary in its path, the canal dives under the Tsubo and Yamada rivers through a series of inverted siphons, this one taking it beneath the Yamada. On the ground it reads as a tidy stretch of engineered waterway — approach channels, valve and trash-rack structures and the head points where the buried pipe rises back to the surface on either bank — managed by the local irrigation district and open to view without admission. It is best treated as a stop on a self-guided tour of the canal system rather than a single attraction.
