An Irrigated area is said to be waterlogged -
When the shallow water table rises to such an extent that soil pores in the root zone of a crop become saturated, resulting in restriction of the normal circulation of the air or
When the surplus water stagnates due to poor drainage.
The Presentation contributes an overall study of the term Waterlogging, its Effects, Causes and steps that needs to be taken for its Prevention.
3. INTRODUCTION
Ministry of Water Resources estimated in 2001 that an
area of 2.04 million hectare was suffering from the
problem of water logging under irrigation commands.
This accounts for nearly 4% of net area irrigated in the
country
Out of this, an area of 1.4 million hectare was estimated
to be suffering from surface water stagnation and 0.64
million hectare through rise in water table.
Worldwide, about 10% of all irrigated land suffers from
water logging.
4. INTRODUCTION
AN IRRIGATED AREA IS SAID TO BE
WATERLOGGED
WHEN THE SHALLOW WATER TABLE RISES
TO SUCH AN EXTENT THAT SOIL PORES IN
THE ROOT ZONE OF A CROP BECOME
SATURATED, RESULTING IN RESTRICTION
OF THE NORMAL CIRCULATION OF THE AIR
IN O2 & CO2
WHEN THE SURPLUS WATER STAGNATES
DUE TO POOR DRAINAGE
5. INTRODUCTION
The actual depth
of water table,
when it starts
affecting the yield
of the crops
adversely, may
vary over a wide
range from zero
for rice to about
1.5 meters for
other crops
Height of
capillary fringe
Type of crop
PICS CROPS DEPTH OF
WATER TABLE (m)
wheat 0.9 to 1.2
Cotton 1.5 to 1.8
Rice 0.6
Sugarcane 0.9
Fodder crop 1.2
6. MINISTRY OF WATER RESOURCES ADOPTED IN
1991, THE FOLLOWING NORMS FOR
IDENTIFICATION OF WATER LOGGED AREAS:
IRRIGATION AREAS WATER TABLE
Water logged Areas
(Due to rise in water Table)
Water table within 2 meters
of the land surface
Potential Areas for
water logging
Water table between 2 to 3
meters below land surface
Safe Areas Water table below 3 meters
of land surface
7. EFFECTS OF WATER LOGGING
Absence of aeration of soil in the root zone of
the plants
Difficulty in cultivation operations
Growth of water weeds & wild aquatic plants
Rise of salts in surface layers
Restricted root growth
Lower soil temperature
Plant diseases
8. CAUSES OF WATER LOGGING
Seepage from
canals
Over irrigation of
fields
Inadequate surface
drainage
Incorrect &
Defective methods
of Irrigation
Obstruction of
natural drainage
Obstruction of
subsoil drainage
Obliteration of
natural drainage
Nature of soil black cotton
soil
Construction of a
reservoir
9. Water logging causes yellowing of leaves, stunted
growth, small and shallow root systems. Also
particularly nitrogen deficiency causes yellowing of
the leaves in winter
10. PREVENTION OF
WATER LOGGING
REDUCING PERCOLATION FROM IRRIGATION
CHANNELS
REDUCING PERCOLATION FROM WATER
COURSES AND FIELDS
ENCOURAGING ECONOMICAL USE OF WATER
INCREASING OUTFLOW FROM THE GROUND
WATER RESERVOIR
11. PREVENTION OF WATER LOGGING
REDUCING PERCOLATION FROM
IRRIGATION CHANNELS
LINING OF CHANNELS
LOWERING OF FULL SUPPLY LEVEL OF
IRRIGATION CHANNELS
PROVIDING INTERCEPTOR DRAINS
AMONG CHANNELS
13. PREVENTION OF WATER LOGGING
REDUCING PERCOLATION FROM
WATER COURSES AND FIELDS
LINING OF WATER COURSES
CONTROLLING INTENSITY OF
IRRIGATION
14. PREVENTION OF WATER LOGGING
ENCOURAGING ECONOMICAL USE OF
WATER
EDUCATING THE CULTIVATORS TO USE
WATER ECONOMICALLY
CHANGING CROP PATTERN
CHANGING REVENUE POLICY
15. PREVENTION OF WATER LOGGING
INCREASING OUTFLOW FROM THE
GROUND WATER RESERVOIR
PROVIDING A DRAINAGE SYSTEM
IMPROVING THE NATURAL DRAINAGE OF
THE AREA
PUMPING GROUND WATER
18. CASE STUDY
crop 1951-52
( yield per
hectare )
1959-60
( yield per
hectare )
cotton 7.32 kN 0.098 kN
wheat 13.18 kN 8.79 kN
To study the effect of
water logging on crop
production, a study was
made at a small farm at
Rauni near Patiala (Punjab)
The study showed
the difference in yield per
hectare as follows:
19. CONCLUSION
UNDER THE RESTRUCTURED CAD PROGRAMME
IMPLEMENTED FROM THE FINANCIAL YEAR 2004-05, THE
COST NORM FOR RECLAMATION OF WATER LOGGED
AREA HAS BEEN INCREASED FROM RS.12000 PER.HEC
TO RS.15000 PER.HEC
SO WITH THE INCREASING LOST, IT IS BETTER TO TAKE
THE PREVENTIVE MEASURES BEFORE HAND
AS WE KNOW “ PREVENTION IS BETTER
THAN CURE ”