Terminology for channel structures on trestles Open channels carried above ground on a series of trestles are generally referred to as:

Introduction / Context:
Conveyance structures that carry water across depressions, valleys, or obstacles may be supported above ground. Different names are used depending on whether the section is open channel or closed conduit and on how it is structurally supported.

Given Data / Assumptions:

• Structure is an open channel element.
• It is supported on trestles (bents or frames).
• It spans over ground rather than being buried.

Concept / Approach:
A flume is an elevated open channel, commonly of wood, metal, or concrete, supported by trestles or bents. An aqueduct is often a larger bridge-like structure conveying water (sometimes masonry arches), but in hydrotechnical parlance “flume” specifically signals an open channel on supports. A siphon is a closed conduit that flows under pressure.

Step-by-Step Solution:

Verification / Alternative check:
Design manuals and hydraulic engineering texts consistently define flumes as open channels supported above ground, frequently on trestles.

Why Other Options Are Wrong:
Raised canal is generic and not standard terminology; aqueducts are broader bridge structures and not necessarily on trestles; siphons are pressurized closed conduits; “conduits” are enclosed and non-specific.

Common Pitfalls:
Using “aqueduct” for all elevated conveyances even when the element is a lightweight trestle-supported open channel.

Final Answer:
Flumes