This Architectural Drawing is of Tunnel Portal Detail Drawing. Aqueduct: In an aqueduct, the canal bed level is above the drainage bed level so canal is to be constructed above drainage. A canal trough is to be constructed in which canal water flows from upstream to downstream. This canal trough is to be rested on number of piers. The capacity of a canal is the maximum discharge that can safely be transported. This means that when the discharge equals the capacity, the water level reaches the minimum required free board level. To exercise control on discharge, full supply level, velocity of flow, silting etc. various masonry or concrete structures have to be constructed over the canals. All these structures are know Canal Regulation Works. For more details and information download the drawing file.