Factors affecting Duty and Improvement Measures L.D. College of Engineering, Ahmedabad-15
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Factors affecting Duty and Improvement Measures
L.D. College of Engineering, Ahmedabad-15
Page 2
Group members:
Sr. No. Name Enrollment No.
1. Patel Pranjal 130280106086
2. Patel Vaibhav 130280106088
3. Patel Vedant 130280106089
4. Patel Vishesh 130280106090
5. Patni Mo.Aamir 130280106091
Page 3
Content
Introduction
Factors affecting duty
Measures to improve duty
References
Page 4
Introduction
The term “Duty” means the area of land that can be irrigated with unit volume of
irrigation water.
Quantitatively, duty is defined as the area of land expressed in hectares that can be
irrigated with unit discharge, that is, 1 cumec flowing throughout the base period,
expressed in days.
Imagine a field growing a single crop having a base period B days and a delta ∆ mm
which is being supplied by a source located at the head (uppermost point) of the field,
as shown in next slide.
Page 5
Introduction (cont..)
[Border Irrigation method of applying water]
[Furrow Irrigation method of applying
water]
[Water applied to field by pumping
ground water]
Page 6
Introduction (cont..)
If the water supplied is just enough to raise the crop within D hectares of the field,
then a relationship may be found out amongst all the variables as:
Volume of water supplied = B*60*60*24 cum
Area of crop irrigated = D*10000 sqm
Hence, knowing two of the three variables B, D and ∆ the third party may be found
out.
Volume of water supplied per unit area = =
86400B10000D
8.64BD
Page 7
Factors affecting Duty
Coarse grained soil
Fine grained soil
Type of soil
Page 8
Factors affecting Duty (cont..)
Crop A
Crop B
Type of crop
Page 9
Factors affecting Duty (cont..)
Good structure
Good structure
Structure of Soil
Good structure is called Good Tilth of Soil
Page 10
Factors affecting Duty (cont..)
Steep slope
Flat slope
Slope of Ground
Properly prepared field
Equal distribution of
waterHigh duty
Page 11
Factors affecting Duty (cont..)
Temperature and wind velocity are high
Rainfall during base period
Climatic Conditions
Page 12
Factors affecting Duty (cont..)
Properly ploughed & made quite loose
Not properly ploughed & method of cultivation is faulty & less efficient
Method of Cultivation
Page 13
Factors affecting Duty (cont..)
Perennial
Non-perennial
System of
Irrigation
Page 14
Factors affecting Duty (cont..)
Tank Irrigation
Canal IrrigationCanal Irrigation Command area
far from source
Transmission losses are
moreLow duty
Page 15
Factors affecting Duty (cont..)
Lift Irrigation
Flow Irrigation
System of
Irrigation
Page 16
Factors affecting Duty (cont..)
Drip Irrigation
Sprinkler Irrigation
Application of Water
Surface irrigation
More waste of water Low duty
Duty of subsurface methods > Duty of surface methods
Page 17
Factors affecting Duty (cont..)
Initial stages of cultivation
Age of cultivation increases
Age and frequency of cultivation
Frequent cultivation
Cultivation after long interval
More loss of moisture Low duty
Page 18
Factors affecting Duty (cont..)
Canal A
Canal B
Condition, type and
location of Canal
Canal A
Canal B
Located away from command
area
Losses are more
Low duty
Duty of Lined canal > duty of unlined canal
Duty of canal in alluvial soil > duty of canal in non-alluvial soil
Page 19
Factors affecting Duty (cont..)
Flat rate based assessment
Volumetric assessment
Method of assessment
of Water
Skill of Cultivators
Cultivators Skilled & properly trained
Make judicious use of water High duty
Page 20
Factors affecting Duty (cont..)
Long base period
Base period
Soil ContentSoil Contains harmful
salts and alkalis
More water required for
leaching of saltsLow duty
However it is not always proportional
Page 21
Measures for Improvement of Duty
Land should be properly ploughed
Land should be regularly cultivated
Canal alignment in sandy soils or in fissured rocks should be avoided
Canal should be located in the middle of command area
Canal should be lined
Canal should be properly maintained
Efficient methods of irrigation should be adopted
Page 22
Measures for Improvement of Duty (cont..)
Volumetric assessment of water should be adopted
Cultivators should be trained
System of rotation of crops should be adopted
Canal alignment through soil containing harmful salts should be avoided
Instead of a single big canal, two or more parallel canals of small size should be preferred
Adopt modern methods of irrigation instead of conventional methods
Cultivators at all levels of canal should get the sufficient quantity of water when needed
Page 23
References
Dr. K. R. Arora (Reprint 2013) Irrigation, Water Power and Water Resource
Engineering, Standard Publishers Distributers, Delhi
Internet content
Page 24
Thank you
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