ANS:C - super passage

The hydraulic structure in which the drainage is passing over the irrigation canal is known as the Super Passagesuper passage. This structure is suitable when the bed level of drainage is above the flood surface level of the canal. The water of the canal passes clearly below the drainage.

A super passage is similar to an aqueduct, except in this case the drain is over the canal.

The FSL of the canal is lower than the underside of the trough carrying drainage water. Thus, the canal water runs under gravity.