If the path of an irrigation canal is below the bed level of a natural stream, the type of cross drainage structure provided is
Super passage
Understanding Cross Drainage Structures
When an irrigation canal and a natural stream (or drain) cross paths, specialized structures are needed to manage their interaction without hindering the flow of either. These structures are known as cross drainage structures. The type of structure chosen depends on the relative bed levels of the irrigation canal and the natural stream.
Super Passage Explained
A Super passage is a type of cross drainage structure where a natural stream or drain is carried over an irrigation canal. This specific arrangement is provided when the bed level of the natural stream is significantly higher than the full supply level (FSL) of the irrigation canal. In other words, if the path of an irrigation canal is below the bed level of a natural stream, it means the natural stream is at a higher elevation, requiring it to pass over the canal.
Key characteristics of a Super passage:
- The natural stream's bed level is above the full supply level of the irrigation canal.
- Water from the natural stream flows in a trough or channel built above the irrigation canal.
- The irrigation canal flows freely underneath, typically in an open cut or through a barrel structure.
- It ensures that the two water bodies remain separated and do not interfere with each other's flow.
Comparing Cross Drainage Structures
To better understand why Super passage is the correct choice for the given condition, let's compare it with other common cross drainage structures:
| Structure Type | Relative Levels (Stream vs. Canal) | Description |
|---|---|---|
| Super passage | Natural stream bed level is above irrigation canal full supply level. | The natural stream passes over the irrigation canal. This matches the condition where the irrigation canal path is below the bed level of a natural stream. |
| Aqueduct | Irrigation canal full supply level is above natural stream bed level. | The irrigation canal passes over the natural stream. This is the opposite of the condition described in the question. |
| Sluice gate | Not applicable as a primary cross drainage structure type. | A sluice gate is a control device used to regulate water flow, often part of larger structures, but not a type of cross drainage structure itself for intersecting waterways. |
| Level crossing | Both irrigation canal and natural stream are at approximately the same level. | Both the irrigation canal and the natural stream intersect at the same elevation. This requires careful regulation and leads to mixing of waters, which is generally avoided unless unavoidable. |
Based on the scenario described, where the path of the irrigation canal is below the bed level of a natural stream, the natural stream must be conveyed over the canal. This precise requirement is met by a Super passage.
Important Questions from Cross Drainage Works
When the HFL of the drain is sufficiently below the bottom of the canal, so that the drainage water flows freely under gravity, the structure is known as _______
The velocity of drainage water in the barrels of syphon aqueduct is normally limited to
- A cross drainage structure in which the drain is taken over a canal, the canal water runs freely under gravity is -
______ is a passage for water over a natural ground having a deck slab over it as path way for vehicles.
The distance between bottom of the bridge super structure and H.F.L is known as____.
