The area in which crop is grown at a particular time of crop season, is called
Culturable Cultivated Area is the area in which crop is grown at a particular time or crop season.
The canal, which can irrigate only on one side, is a
Ridge/Watershed Canal: The dividing ridge line between the catchment areas of two streams (drains) is called the watershed or ridge canal. It is suitable for plain areas, where slopes are relatively flat and uniform. This type of alignment ensures gravity irrigation on both sides of the canal.
Contour Canal: Canal aligned nearly parallel to the contour line is called contour canal. They are aligned generally when canals take off from a river. Culturable area lies on one side of it as one of the banks is on the higher side.
Side Slope Canal- A side slope canal is that which is aligned at right angles to contours i.e. along the side slopes. It is a canal which is aligned roughly at right angle to contours of the country but not on the watershed of the valley. The canal thus, runs parallel to the natural drainage of the country and as such cross drainage works are avoided.
The capacity of an irrigation canal is usually controlled by
When electrical conductivity of irrigation water is upto ______ micro mhos/cm, it is called low conductivity water
The following structure serves the purpose of a ‘safety valve’ for a canal
It is the structure required to dispose of surplus or excess water from canal from time to time. Thus, a canal escape serves as safety valve for canal system. It provides protection to the canal from possible damage due to excess supply which may be due to mistake in releasing water at head regulator or heavy rainfall that makes sudden regular demand of water.
The following data pertain to a natural drain crossing an irrigation canal
Which one of the following types of crossdrainage should be recommended in this case ?
What type of cross drainage work is provided when the canal runs below the drain, with FSL of canal well below the bed of the drain ?
If bed level of canal is sufficiently above the HFL of the drain, an aqueduct is the right choice. Sometimes bed level of canal may be little below the HFL of drain so that water flows under symphonic action. This structure is known as aqueduct siphon. If bed level of the drain is sufficiently above the canal FSL, a super passage may be constructed. If the canal FSL is little above bed level of drain to allow symphonic action, the structure is called Canal Siphon. Aqueduct or super-passage type of drainage works are used when high flood discharge is large and continues for a sufficient time. A level crossing is used when the canal water and drain water are allowed to intermingle with each other. This is adopted when high flood drainage discharge is short lived.
Consider the following statements :
An aqueduct is a cross drainage work in which
1. a canal is carried over the drainage channel.
2. a drainage channel is carried over the canal.
3. both drainage channel and canal are at the same level.
Which of these statements is/are correct ?
Consider the following statements :
1. In a super-passage, the drain runs over the canal.
2. In a siphon, the drain runs below the canal.
3. In a siphon aqueduct, type-II, the canal banks are made of RCC walls.
Which of these statements are correct ?
A lined alluvial canal is best designed on the basis of
Lining of irrigation channels
Canal lining is the process of reducing seepage loss of irrigation water by adding an impermeable layer to the edges of the trench. Seepage can result in losses of 30 to 50 percent of irrigation water from canals, so adding lining can make irrigation systems more efficient so there is increase in command area.
Safety ladders are provided in large irrigation canals, to
The main advantage offered by Bentonite layer lining in an irrigation canal is that:
Advantages of Canal Lining:
An important reason for lining a canal can be the reduction in water losses, as water losses in unlined irrigation canals can be high. Canals that carry from 30 to 150 liters/sec can lose 10 to 15% of this flow by seepage and water consumption by weeds. Lining a canal will not completely eliminate these losses, but roughly 60 to 80% of the water that is lost in unlined irrigation canals can be saved by a hard-surface lining.
Under-drainage arrangements in canals are necessarily required in
In the alignment of an irrigation channel wherefrom offtakes have to be provided at regular intervals, changes in the given channel parameters are made use of. The correct sequence of the decreasing order of preference of these parameters is
Theoretically the best cross section for a lined canal is
A land is said to be water-logged, when
Water-logging of cropped land leads to reduced crop yields, due to
Which one of the following does not contribute to water logging?
Which one of the following is not a remedial measure for water logging?
Alkaline soils are best reclaimed by
The method, which uses dead furrows on cropped farms for drainage of excess irrigation or rain water, is called:
A recently reclaimed alkaline soil should preferably be sown with a salt resistant crop, like
Acidic soils are reclaimed by
Leaching is a process
Leaching is a process of extracting a substance from a solid material that is dissolved in a liquid. Thisprocess is commonly referred to as extraction, particularly in the chemical industry. Three basic steps are involved in the leaching process: contact, separation, and extraction.