Waterlogging Types & Causes of Waterlogging Effects & its control Salinity Effects with figure & its control water resource engineering by Denish Jangid Sir unit 4 WRE

waterlogging with figures water resource engineering by DJ sir unit 4 WRE
Water logging, effects & its control salinity, effects & its control water logging types & causes of waterlogging
Effects of waterlogging on plant growth causes of salinity effects of salinity measures to control salinity preventive measures curative measures
How to Prevention of water logging.
Water Logging: Causes, preventive and curative measures, drainage of
irrigated lands, saline and alkaline lands, types of channels lining and design
of lined channel.

1. Subject- Water Resources Engineering By Denish Jangid Assistant Professor Civil Engineering Department Water -logging

2. Water logging, Effects & its control Salinity, Effects & its control

3. The soil whose surface layers are saturated with water is called as waterlogged soil. The phenomenon of rising of water table is known as waterlogging

4. 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 .

5. 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 O 2 & CO2 WHEN THE SURPLUS WATER STAGNATES DUE TO POOR DRAINAGE

6. Water logging causes yellowing of leaves, stunted growth, small and shallow root systems. Also particularly nitrogen deficiency causes yellowing of the leaves in winter

7. The States mainly affected and the extent of area rendered infertile and unproductive are given in Table 11.1.

8. INT R ODU C TION 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 . 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.

9. CAUSES OF WATERLOGGING 1. Seepage of water from canal system The main cause of waterlogging in pakistan is seepage of water from network of canal system.40-50% water is lost from main canals ,seeps through soil and rised the ground water. In some cases the water table has risen upto root zones or even surface of soil. 2. Poor surface runoff and slow drainage The soil surface of pakistan is flat so surface runoff is poor and hence slow drainage, result in accumulation of water on soil surface and move to the water table under the influence of gravity. The water table has risen causes water logging

10. C AUSES OF WATERLOGGING 3. Interruption of surface runoff. Construction of irrigation networks and housing colonies in the path of natural drains interrupted surf ace runo f f , r esu l ting in accumul a tion of w a ter in rainy season contributes to waterlogging through seepage. 4. Rainfall. After heavy rainfall rain water percolates down the pores between soil particles under the action of gravity. 5. Floods. Flood water spreads on the surface of soil in plains. Due to inappropriate drainage system, this water percolates in soil and raise water table cause waterlogging.

11. C AUSES OF WATER LOGGING 6. Poor water management Sometimes farmers use their land unscientifically . Excessive irrigation Lack of inadequate drainage system. 7. By breaking hardpan at a canal bed. During cleaning season ,the digging of canals breaks the hardpan of the soil at canal bed. It enhances the seepage of water. 8. Railway lines /Roads. The construction of railway lines and roads in food plains interrupted the passage of runoff water ,water collected in rainy season in the form of ponds ,percolates to soil, Result in waterlogging.

12. EFFECTS OF WATERLOGGING ON PLANT GROWTH Some important effects of waterlogging on plant growth are given below; The air in the soil pore is replaced by water ,leading to oxygen deficiency and hence reduce the plant growth. In waterlogged soil transport of gases is reduced disturbing normal growth. Limited exchange of gases increase amount of co2 which affect transpiration and water absorption. iv. In absence of oxygen, microbes produce toxis substances such as methane and effects growth of plants.

13. EFFECTS OF WATERLOGGING ON PLANT GROWTH

14. Salinity If the concentration of harmful salts in the root zone of a plant increases to such on extent that plant growth is effected, this situation is called Salinity.

15. SOIL SALINITY Soil salinity refers to presence of salt in root zone of soil. It adversely affects the growth of plants. General symptoms of salinity; Retarded growth. Smaller plants with few leaves. Dark green than normal leaves. About 48 lakh ha are estimated to be affected by salinity and 25 lakh ha by alkalinity. Saline soils include 10 lakh ha in arid and semi-arid regions of Rajasthan and Gujarat and 14 lakh ha in black cotton soils. The alkali problem is mainly in Punjab, Haryana and Uttar Pradesh.

16. The factors contributing towards the problem of salinity are almost same as that of water logging. Every agricultural soil has certain mineral salt is also called alkali salts in it like NaCl , Na 2 CO 3 , Na 2 SO 4 etc. When these soluble alkali salts are excess in soil and further ground water table is very near to ground, these salts get mixed with ground water and with upward movement of   water not only accumulated in first 3~4ft of soil layer below ground surface but also form a tin 2”~3” crust on surface. Causes of Salinity

17. Corrosive Action to Plants. Formation of Alkali Soil . Effects of Salinity

18. Preventive Measures Curative Measures Measures To Control Salinity

19. Controlled Irrigation. Providing adequate surface drainage. Allowing lower intensity of irrigation. Reducing surface evaporation. Not using alkaline water for irrigation purpose. Preventive Measures

20. Treatment by Leaching Process Chemical Treatment Treatment by Mulching Curative Measures

21. Treatment by Leaching Process Leaching  is the  process  of extracting minerals from a solid by dissolving them in a liquid, either in nature or through an industrial process . In the chemical  processing  industry,  leaching  has a variety of commercial applications, including separation of metal from ore using acid, and sugar from beets using hot water. Step 01. Providing adequate sub surface artificial drainage. Step 02. Leaching salts from the top 3~4ft of soil to ground water table by flooding the land. Step 03. Growing salt resistant crops (e.g. rice) for one or two seasons.

22. Chemical Treatment PRINCIPLE Mixing gypsum CaSO 4 (@ 1 ton/acre) with salt effected soil in presence of water. CaSO 4 +Na 2 CO 3 ---------> Na 2 So 4 +CaO +CO

23. Treatment by Mulching Mulch  is simply a protective layer of a material that is spread on top of the soil.  Mulches  can either be organic -- such as grass clippings, straw, bark chips, and similar materials -- or inorganic -- such as stones, brick chips, and plastic It involves covering the effected land with a covering of soil (Mulch) to reduce evaporation losses.

24. SALT EFFECTED OR THUR SOILS The soils in which concentration of salt is very high are called salt effected soil or thur soil. Salt effected is a collective term which includes saline, sodic and saline sodic soil. It occur c o m m on l y in a rid and semiarid regi o ns , as well as humid and sub humid regions. Salt effected soil has sodium,calcium,potassium,carbonates and bicarbonates.

25. TYPES OF SALT EFFECTED Primary salt effected soil. Secondary salt effected soil . a)Primary salt effected soil. The soil that develops as a result of natural causes (imperfect drainage of surface and ground water).are called primary salt effected soil. b) Secondary salt effected soil. The soil that develops due to accumulation of salt as a result of rise in ground water table are under faulty system of irrigation are called secondary salt effected soil.

26. PROCESSES OF FORMATION OF SALT EFFECTED SOIL. a) Salination. Salination is the process of accumulation of soluble salts by which saline soil are formed . b) Desalination. The process of leaching of soluble salts out of root zone is called desalination. c) Sodication. Sodication is the process of accumulation exchangeable sodium in the soil which results in the formation of sodic soil.

27. PREVENT I ON 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

28. 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

29. LINING OF CHANNELS REDUCING FSL

30. PREVENTION OF WATER LOGGING REDUCING PERCOLATION FROM WATER COURSES AND FIELDS lining of water courses controlling intensity of irrigation

31. PREVENTION OF WATER LOGGING ENCOURAGING ECONOMICAL USE OF WATER Educating the cultivators to use water economically Changing crop pattern Changing revenue policy

32. 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

33. END

34. 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.