Water logging problems due to the construction of dams andcanyon and reservoirs

Water logging problems due to the construction of dams andcanyon and reservoirs

1. WATER LOGGING PROBLEMS DUE TO
THE CONSTRUCTION OF DAMS ,
CANYON AND RESERVOIRS

2. CONTENTS ;
INTRODUCTION
WATERLOGGING and SALINITY
CAUSES
PROBLEMS DUE TO WATERLOGGING
TYPES OF WATERLOGGING
WATERLOGGING BY DAMS
WATERLOGGING BY RESERVOIRS
CONTROLS OF WATERLOGGING
CONCLUSIONS
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3. INTRODUCTION
Water-logging refers to the saturation of soil With water. Soil may be 
regarded as waterlogged when the water table of the groundwater is too 
high to conveniently permit an anticipated activity, like agriculture.
In agriculture, various crops need air (specifically, oxygen) to a greater or 
lesser depth in the soil. Water-logging of the soil stops air getting in. How 
near the water table must be to the surface for the ground to be classed as 
waterlogged, varies with the purpose in view. A crop's demand for freedom 
from water-logging may vary between seasons of the year, as with the 
growing of rice (Oryza sativa).
In irrigated agricultural land, water-logging is often accompanied by soil 
salinity as waterlogged soils prevent leaching of the salts imported by the 
irrigated water.
From a gardening point of view, water-logging is the process whereby the 
soil blocks off all water and is so hard it stops air getting in and it stops 
oxygen from getting in.

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9. Water Logging and
Salinity ;
 As a result, the lands become uncultivable. In some cases, the
underground water does not reach the upper level of lands but
remains slightly lower and the land salts gather near the roots of
the plants such situation is called Salinity. In this case, the
sufficient amount of water is not available for irrigation, hence
the salts are not absorbed in the land after having mixed.
These salts gather in the form of a layer in the upper level of
land. Thus due to water logging and salinity the water retains
itself on the surface of land and salts gather themselves in the
zones of roots of plants. This leads to decrease the efficiency and
productivity of lands and finally lands become uncultivable.

10. CAUSES
Over irrigation.
Canal irrigation in areas adjoining agricultural lands where
subsoil water table steadily rises.
Inadequate drainage.
Surface flooding.
Construction of dams and reservoirs.
Presence of high water table.
During monsoon & soon after some areas remains totally
submerged by the discharge of the rivers & accumulation of
runoff from the surrounding catchment.
Water logging conditions are also caused in depressions along
roads, canals & railway sides during rainy season.
Sea water comes to a particular area during high tidal surges.

11. PROBLEMS DUE TO WATER LOGGING

· It creates anaerobic condition in soils for
which microbial activity is hampered.
· The availability of nutrient elements in
soil is reduced & leaching loss is higher.
· Increases soil pH in coastal & dry area
which leads salinity & alkalinity.
· Pollutes soil water & favors excessive
weed growth.

12. TYPES OF WATER LOGGING
1) Water logging due to permanent submersion of
land. Such as ponds, rivers, etc.
2) Water logging from periodical submersion such as
coastal & estuarine land inundation by soil water or
runoff of freshwater over lands etc.
3) Temporary water logging by stagnation of water
as a result of heavy rainfall.
4) Water logging by coming out of water table to the
surface & swampy areas in valleys are mostly caused
by the phenomenon.
5) Water logging from artificial irrigation of
agricultural lands in polders areas.
Dams, Reservoir's and canyons

13. Water logging caused by
constructions of dams ;
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14. Water logging:
Rich soils in the states of Punjab and Haryana have been
robbed for their use because of water logging. The Indian
Institute of science estimates that 40 percent of the
command area for Sardar Sarovar Dam will become
waterlogged. This area contains black cotton soils which are
particularly prove to water logging under perennial
irrigation due to high water retention capacity. Soils
become water logged and crop yields fall.
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15. Effects by Reservoirs ;
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19. MEASURES TO REDUCE IT
· Construction of dams & embankments along the
coast to restrict saline to enter the agricultural lands.
Could be an effective measure of reducing the
water logging.
· Providing adequate number of bridges & culverts,
along the roads, railroads, highways, across the
canal etc could be a handy measure against water
logging.

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26. REFFERENCE ;
Keller E A – Environmental Sciences
Pages : 84 – 91 , 121-125.
Santra S C - Environmental Science
Wikipedia.com

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27. THANK YOU