Other Industrial Engineering & Manufacturing Subjects
Irrigation - Industrial Engineering & Manufacturing
Practice questions to test your knowledge and improve your understanding.
In a canal syphon, the flow is
Explanation:
A canal syphon functions as a closed conduit that transports water from a higher elevation to a lower one, completely filling the pipe with liquid. Since the entire flow path is enclosed within the pipe walls, the fluid dynamics are governed by pipe flow principles rather than open channel flow. This configuration ensures that the water moves continuously under pressure, distinguishing it from surface flows where the top boundary is free. Therefore, the fundamental nature of the flow in a canal syphon is classified strictly as pipe flow.
F.S.L. of a canal at its head with respect to parent channel is kept
Explanation:
The Full Supply Level (F.S.L.) at the head of a canal is maintained 15 cm lower than the parent channel to prevent seepage losses and ensure the canal bed remains above the water table. This elevation difference creates a hydraulic gradient that allows water to flow smoothly into the canal while minimizing the risk of the canal bed becoming submerged or unstable. Keeping the head regulator slightly lower facilitates better control over the inflow and protects the canal structure from excessive pressure or erosion caused by high water levels. This design principle is fundamental in irrigation engineering to optimize water delivery efficiency and maintain the structural integrity of the canal system.
For smooth entry of water in a canal, the angle between head regulator and water is generally kept
Explanation:
The angle between the head regulator and the water surface is typically maintained at approximately 110° to ensure smooth entry of water into the canal. This specific obtuse angle minimizes hydraulic resistance and prevents the formation of a hydraulic jump or excessive turbulence at the entrance. By allowing the water to enter with a gentle slope, this design effectively reduces energy losses and prevents sediment deposition within the canal head. Consequently, maintaining this angle is crucial for efficient water conveyance and the long-term stability of the canal structure.
The crest level of a canal diversion head work, depends upon
Explanation:
The crest level of a canal diversion head work is fundamentally determined by the pond level, which represents the maximum water surface elevation in the reservoir. This level dictates the maximum potential energy available for irrigation and ensures that water can flow into the canal under gravity when the pond level exceeds the canal's full supply level. Consequently, since the pond level is the primary governing factor for this design parameter, the correct choice encompasses all relevant considerations tied to this hydraulic relationship.
When a canal is carried over a natural drainage, the structure provided, is known as
Explanation:
An aqueduct is the specific structure used when a canal is carried over a natural drainage or river, allowing water to flow by gravity across the obstacle. This design maintains the canal's original bed level above the drainage, ensuring continuous water transport without interference. The structure typically consists of a trough supported by masonry arches or piers that span the width of the watercourse. By elevating the canal, it prevents the drainage from entering the water supply while maintaining the necessary hydraulic gradient. This configuration is distinct from other structures like syphons, which are used when the canal bed is lower than the drainage. Therefore, the term aqueduct accurately describes this elevation and crossing mechanism.
The measure to remove water logging of land, is
Explanation:
Water logging occurs when the water table rises too close to the surface, often due to excessive seepage from irrigation canals. The primary solution involves minimizing this percolation to prevent the groundwater reservoir from filling up unnecessarily. Simultaneously, increasing the natural outflow allows excess water to drain away from the soil profile effectively. By combining reduced input with enhanced drainage, the water table is lowered to a safe depth, restoring healthy soil conditions for agriculture. This dual approach addresses both the source of excess water and the pathway for its removal.
The useful moisture of soil, is equal to its
Explanation:
Useful moisture represents the specific volume of water in soil that plants can actually absorb and utilize for growth. This quantity is defined as the difference between field capacity, where the soil holds maximum water after drainage, and the permanent wilting point, where moisture is too low for plants to recover. Consequently, only the water stored within this specific range between these two critical thresholds is considered beneficial and accessible to the root system.
A hydraulic structure is designed to withstand
Explanation:
Hydraulic structures are engineered to endure a complex combination of physical phenomena inherent to fluid mechanics. They must simultaneously resist the erosive power of seepage forces acting on the foundation, manage the energy dissipation associated with hydraulic jumps, and withstand the immense hydraulic pressure exerted by the retained water. Since a functional design requires protection against all these critical mechanisms to ensure stability and safety, the correct choice encompasses every listed factor. Therefore, the structure is designed to withstand all these conditions collectively.
Retrogression of the bed level of a river downstream a weir, occurs due to
Explanation:
Retrogression of the river bed downstream a weir occurs because the water released from the weir carries a significantly reduced percentage of silt compared to the natural upstream flow. This lower sediment load creates a deficit in the river's ability to transport its full capacity of material, leading to a net scouring action that lowers the bed level. As the river attempts to re-establish its equilibrium profile, it erodes the downstream channel until the sediment transport capacity matches the available load. Consequently, the bed level drops progressively until a new stable equilibrium is reached, making the reduced silt percentage the primary cause.
For the conditions enumerated to provide a crossing at C1 You will probably provide
Explanation:
A super-passage is the correct choice because it is specifically designed to carry a canal over another waterway or road at a higher elevation, ensuring the water level remains above the obstacle. This structure effectively meets the crossing conditions by maintaining the canal's gradient and flow without interference from the terrain below. It functions as a bridge-like structure that allows uninterrupted water transport while accommodating the crossing requirements at point C1.
The saturation line is the line up to which banks get saturated after the canal runs for some time. The saturation gradient in ordinary loam soil, is generally
Explanation:
The saturation line represents the depth to which soil moisture reaches under continuous canal flow, defining the limit of the saturated zone. In ordinary loam soil, the hydraulic conductivity and soil texture typically result in a saturation gradient of approximately 4:1, meaning the water table rises 4 units vertically for every 1 unit of horizontal distance from the canal. This specific ratio is a standard empirical value used in irrigation engineering to estimate the extent of seepage and potential waterlogging risks. Understanding this gradient is crucial for designing drainage systems and managing soil health effectively.
A fall in a canal bed is generally provided, if
Explanation:
A fall in a canal bed is constructed when the natural ground slope is steeper than the designed bed slope required for the canal. Since the ground drops too rapidly, the canal bed must be lowered step-by-step using structures called falls to maintain the intended gentle gradient. This prevents excessive flow velocity that could cause erosion and ensures the canal remains stable and functional. Without these falls, the water would flow too fast, potentially damaging the canal banks and undermining the structure's integrity. Therefore, providing a fall is the standard engineering solution when the terrain is too steep for the desired canal slope.
Pick up the incorrect statement from the following. Culturable commanded area is the gross area of an irrigation canal system less
Explanation:
Culturable Command Area represents the total land area that can be irrigated by a canal system, excluding specific non-agricultural or unusable zones. The definition explicitly subtracts areas such as alkaline lands, forested regions, and populated zones because they are not suitable for cultivation. Fallow land, however, is agricultural land that is temporarily left uncultivated but remains part of the command area potential. Therefore, subtracting fallow land from the gross area is incorrect, as it is included in the calculation of the culturable command area.
Groynes are generally built
Explanation:
Groynes are typically constructed at an angle of up to 30 degrees inclined upstream to effectively trap sediment moving along the coast. This upstream orientation allows the structure to intercept longshore drift, causing sand to accumulate on the updrift side and thereby widen the beach. By building in this specific direction, the groyne promotes beach accretion and protects the shoreline from erosion caused by wave action. This design maximizes the volume of trapped sediment while maintaining structural stability against the prevailing currents. Consequently, the upstream inclination is the standard engineering practice for successful coastal defense systems.
Attracting groynes are built
Explanation:
Attracting groynes are specifically designed to trap sediment and encourage the formation of a new river bank by angling upstream. This inclination allows the structure to intercept the flow of water and capture drifting sand or silt before it reaches the desired location. As material accumulates against the upstream face, the bank naturally builds outward, effectively widening the river channel and stabilizing the shoreline. This strategic orientation distinguishes them from repelling groynes, which are built perpendicular to the bank to push sediment away. Consequently, their upstream tilt is the defining feature that enables them to attract and deposit material where it is needed most.
Irrigation allowed farms to be _____ rivers.
Explanation:
Irrigation systems enable farmers to cultivate crops in areas distant from natural water sources, effectively allowing farms to be located farther from rivers. By channeling water through canals or pipes, agriculture becomes independent of immediate proximity to large bodies of water. This technological advancement expanded arable land significantly beyond the traditional floodplains and riverbanks. Consequently, settlements and farms could thrive in regions where rainfall was insufficient and rivers were not directly accessible. This shift transformed agricultural geography by decoupling farming success from direct river adjacency.
When a canal flowing under pressure is carried below a natural drainage such that its F.S.L. does not touch the underside of the supporting structure, the structure so provided, is called
Explanation:
This structure is known as a super passage because it functions as a pressure conduit that passes underneath a natural drainage system. The key defining feature is that the Full Supply Level (F.S.L.) of the canal remains below the underside of the supporting embankment or bridge, ensuring the water flows under pressure without touching the structure. This design allows the canal to cross a depression or valley while maintaining its pressurized flow regime, distinguishing it from open aqueducts or siphon-aqueducts where the water level might interact differently with the support.