Terminology – elevated open channel on trestles A water channel constructed above ground level and supported on bents or trestles is generally called what?

Introduction / Context:
In hydraulic conveyance, different structures are used to traverse varied terrain. When an open-channel section must be carried above the ground on a lightweight support system, a specific term is used for that arrangement.

Given Data / Assumptions:

• Open-channel flow conditions (free surface).
• Support on bents/trestles rather than massive bridge piers.
• Typical materials include timber, steel, or light reinforced concrete.

Concept / Approach:
A flume is an above-ground trough or channel, commonly rectangular or trapezoidal, supported on trestles. It carries water across uneven ground without the mass of a full aqueduct. An aqueduct is a broader term often denoting a larger, bridge-like structure carrying a canal or pipeline across a valley. A canal is generally ground-supported, and a tunnel is a closed, underground conduit.

Step-by-Step Solution:
Match the definition: open channel on trestles → flume.Other terms describe different structural contexts.

Verification / Alternative check:
Historic irrigation and mining conveyances used timber flumes extensively; modern flow-measurement devices (e.g., Parshall flumes) echo the term for constrained open-channel sections.

Why Other Options Are Wrong:

• Canal: typically at or below grade.
• Aqueduct: larger bridge-like carrier, not a lightweight trestle-supported trough.
• Tunnel: underground enclosed passage.
• 'All the above' mixes mutually exclusive terms.

Common Pitfalls:
Using 'aqueduct' for any elevated waterway; in exam terminology, 'flume' is the precise term for the trestle-supported open channel.

Final Answer:
Flume