Anna University, Chennai
CE2301 IRRIGATION ENGINEERING UNIT – 1
INTRODUCTION
1) Define irrigation ?
Irrigation is defined as the science of artificial application of water to the land in accordance with the crop requirements.
2) What are the necessity of irrigation ?
1.inadequate rainfall
2.increasing yield of crops
3.growing perennial crops
4.uneven distribution of rainfall.
3) What are the advantages of irrigation?
1.increase in food production
2.optimum benefits
3.general prosperity
4.afforestation.
4) What are the disadvantages of irrigation?
1.over irrigation may lead to water logging
2.it may reduce cropyield
3.it is expensive and complex.
5) What is arid region?
The area where irrigation is must for agriculture is called arid region.
6) What is semi-arid region?
The area in which inferior crops can be grown without irrigation.
7) What is crop period?
The time period that elapses from the instant of its sowing to the instant of its harvesting is called crop period.
8) What is base period?
The time between the first watering of a crop at the time of its sowing to its last watering before harvesting is called the base period.
9) What is rotation period?
The time interval between two such consecutive watering is called frequency irrigation.
10) Define duty of water?
It is the relationship between the volume of water and the area of crops it matures is called duty of water.
11) Define delta of a crop?
Each crop requires a certain amount of water after a certain fixed interval of time, through its period of growth is called delta of a crop.
12) What are the factors on which duty depends?
1.type of crop
2.climate and seasons
3.useful rainfall
4.type of soil
5.efficiency of cultivation method
13) What are kharif crops?
The kharif crops are rice,bajra,jawar,maize,cotton,tobacco, groundnut,etc.
14) What are rabi crops?
Rabi crops are wheat,barley,gram,linseed,mustard,potatoes,etc
15) Define irrigation efficiency?
It is the efficiency of water output to the water input,and is usually expressed as percentage.
16) What is called effective rainfall?
Precipitation falling during the growing period of a crop that is available to meet the evapo-transpiration needs of the crop, is called effective rainfall.
UNIT – 2
IRRIGATION METHODS
1) List some types of irrigation ?
canal irrigation,lift irrigation,tank irrigation,etc
2) What are the necessity of irrigation ?
1.inadequate rainfall
2.increasing yield of crops
3.growing perennial crops
4.uneven distribution of rainfall.
3) What are the advantages of irrigation?
1.increase in food production
2.optimum benefits
3.general prosperity
4.afforestation.
4) What are the disadvantages of irrigation?
1.over irrigation may lead to water logging
2.it may reduce cropyield
3.it is expensive and complex.
5) What are the types of irrigation?
1.surface irrigation
2.sub-surface irrigation.
6) What are the techniques of water distribution in the farms?
1.free flooding
2.border flooding
3.check flooding
4.basin flooding,furrow irrigation method,drip irrigation method.
7)What are the types of sprinkler system?
1.permanent system
2.semi-permanent system
3.portable system
8)what are the advantages of sprinkler irrigation?
1.land levelling is not required
2.fertilisers can be uniformly applied
3.it is less labour oriented
9) what are the limitation of sprinkler irrigation?
1.initial cost of the system is very high
2.it requires larger electrical power
3.high wind may distort sprinkler pattern
10)define tank irrigation?
It is defined as the storage irrigation scheme,which utilizes the water stored on the upstream side of a smaller earth dam
11)define tank banks?
The earthen bunds,spanning across the steams are called tank bunds or tank banks.
12)what is the other name for drip irrigation?
drip irrigation is also called as trickle
irrigation.
13)what is called sprinkler irrigation system?
water is applied to the soil in the form of a spray through a network of pipes and pumps is called sprinkler irrigation system
14)what is called called borders?
land is divided into a number of strips separated by low levees
called borders.
UNIT-3
1) What is meant by canal escape?
Canal escapes are the safety valves of canals &must be provided at regular intervals depending upon the importance of channel& availability of
suitable
drainage for the disposal of the exposed water.
2) State various kinds of dams.
1.earth dams
2.rock fill dams
3.solid masonry gravity dams
4.hollow " " " "
5.timber dams
6.steel dams
7.arch dams
3). State diff types of spillways.
1.straight drop spillway
2.ogee spillway
3.trough spillway
4.side channel spillway
5.shaft spillway
6.syphon spillway
4). What are the various types of dams?
1.earth dams
2.rockfill dams
3.solid masonry gravity
4.hollow “ “
5.timber dams
6.steel dams
7.arch dams
5)What is weir?
The major part of the water is achieved by a raised crest or a small part is achieved by raising shutters then this barrier is known as weir.
6) What is tank sluices?
it is an opening in the form of culvert under the tank bund and supplying water to the distributory channel.
7) Forces acting on arch dams.
1.water pressure
2.uplift “ “
3.earthquake forces
4.silt pressure
5.wave pressure
6.ice “ “
8) Define sluiceway
Pipe or tunnel provided for the withdrawl of water from the dams is known as sluiceway.
9) What is spillway?
Spillway is a structure constructed at a dam site for disposing the surplus water
from upstream to downstream.
10)Types of earthen dams.
1.homogeneous embankment type
2. zoned “ “ “
3. diaphragm type.
11)Define barrage.
the most of the ponding is done by gates and a smaller of it is done by raised crest then the barrier is known as barrage.
12). What are the modes of failure in gravity
dams?
1. by over turning about the toe
2.by crushing
3.by development of tension
4.by sliding
13) Define diversion headwork.
Any hydraulic structure, which offers water to the offtaking canal, is called diversion headwork.
14) What is gravity dam?
a structure which is designed in such a way that its own weight resist external forces and it is more durable .
15)Define stream line.
it represent the path along which the water flows through the subsoil.at a given point in upstream of hydraulic structure will travel its ownpath &will represented the stream line.
16). Types of aeration tanks.
1.air diffusion
2.mechanical aeration
3.combined “ “
17) Limitations of blighs creep theory.
1. no difference b\w hzl & vtl creep
2.hzl distance b\w pipe line is greater than 2 times the depth 3.no idea about exit gradient
1.what do you mean by canal?
Unit - 4
A canal is an artificial channel, generally trapezoidal in shape constructed on the ground to carry water to the fields either from the river or from a tank or reservoir.
2.What are the types of canals?
Alluvial canal
Non-Alluvial canal
3.What is alignment of canals?
Watershed canal contour canal Side slope canal
4.What is distribution system of canal irrigation?
Main canal Branch canal Minor canal Major canal Water courses
5.Define tank banks?
The earthen bunds, spanning across the steams are called tank bunds or tank banks.
6.What is called alluvial soil?
The process of silt deposition may continue over long periods in the formation is called alluvial soil.
7.What is called Non-alluvial soil?
Mountainous regions may go on disintegrating over a period of time, resulting formation of a rocky plain area called non-alluvial soil.
8.What is called Watershed canal?
The dividing ridge line between the catchment areas of two streams is called
Watershed canal.
9.List out the alignment of a fields canal?
They should be laid along field boundaries.
They should be capable of supplying sufficient water to tail
Separate field channels should be provided for high and low lands.
10.Define cross drainage works?
cross drainage work or drainage crossing is a structure constructed to negotiate an irrigation canal over, below or at the same level of drainage or another canal.
11.Define aqueduct and Write the different types of Aqueduct?
Aqueduct is defined as the a drainage crossing in which the canal is carried over the drainage channel and the bottom at the canal trough or the covering over the drainage opening is above the high floods level in the drainage channel.
Types of Aqueduct:
Barrel type Aqueduct Arch type Aqueduct Trough type Aqueduct Buttress Aqueduct
12.Define syphon aqueduct and the types of syphon aqueduct? Syphon Aqueduct:
It is defined as a drainage crossing in which the canal is carried over the drainage channel preferably at right angle of the drainage discharge is carried under pressure through the structure.
Types of Syphon Aqueduct: Trough type Aqueduct
Barrel type Aqueduct
13.What do you meant by super passage?
It is defined as a drainage crossing in which the drainage channel in a trough over the canal normally with full supply level at the canal below the bottom of the trough.
14.List out the collection at site data?
Index plan Catchment plan Site plan Geological plan Rainfall
Discharge and sediment data The canal & drainage data Seismic disturbances
15.Define canal regulators? Head regulators:
The regulates or control the supplies to the off taking channel. They serve as a meter for measuring discharge entering into the off taking canal.
Cross regulators:
They effective regulation of the whole canal system can be done with the help of cross regulator. It helps in closing the supply to the discharge of the Parent channel.
UNIT -5
IRRIGATION WATER MANAGEMENT
1).what are the causes of water loss?
1. seepage from the canal
2. over irrigation of field
3. heavy surface runoff
2) what are ways of water loss in the canal?
1. seepage loss
2. evaporation loss
3) What are factors on which seepage loss depends?
position of water table porosity of sub-soil porosity of soil
extend of absorbing medium
4) What are two different condition of seepage?
1.percolation
2.absorption
5. What are the remedial measures for losses?
1.efficient surface drainage
2..restriction of irrigation
3.change in crop pattern
6) What are the advantages of irrigation water managements?
1 .achievement of optimum irrigation efficiency
2.economical and efficient operation and maintanence of irrigation system
3.equitable distribution of supplies to irrigators especially at the end
7) Discuss some components of water management?
1.water shed management
2.land management
3.rain water management
4.reservoir management
8.What are the impact of water user association?
1.conveyance efficiency
2.operation efficiency
3.equity
4.area water unit ratio
9.) What are the advantages of water user association?
1.better maintenance of the distributry
2.possibility of high value of crop programme
3.availability of water and irrigation process
10) What are optimization of water user association?
1.to reduce the seepage loss and conveyance
2.control over the usage of water
3.planning
4.to avoid excess supply of water
11).what are the factors which influence evaporation loss?
1.temperature
2.wind velocity
3.relative humidity
12. What is land management?
The intensity of raising productivity per unit area per unit time needs to be increased which amounts to increasing croped area.
13. What are the irrigation methods for cultivation?
1.border strip-wheat
2.furrow method –cotton
3.basin method –orchard
14. What are the uses of irrigation waters?
1.wastages due to over irrigation
2.wastages due to surface runoff
3.wastages due to escape of water
15. What are the work of on farm development?
1.irrigation practice
2.crop planning
3.irrigation method
4.right amount of irrigation
16. what are the components of on farm developments?
1.field drain
2.crossing in field channel
3.crossing of field channel
4.formation of field channel
17. What is called optimum water depth?
The quantity of water at which the yield is maximum, is called the
optimum water depth.
18. What is called optimum utilisation of irrigation?
It generally means, getting maximum yield with any amount of
water.
19.what is the relation between efficieny and losses?
efficieny is inversely proportional to the losses.
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