Watershed management

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water resource engineering-I

Watershed management

  1. 1. WATER SHED MANAGEMENT ( p (Special emphasis on soil p and water conservation) WRE-I UNIT- VIIIProf S S JAHAGIRDARBE (CIVIL) ME(ENV ) PhD(persuing) (CIVIL), ME(ENV.),PhD(persuing)NK Orchid college of Engg. and Tech. , Solapur
  2. 2. Watershed:• Definition:“Watershed can be defined as a unit“ h d b d fi d i of area covers all the land which contributes runoff to a common point or outlet and surrounded by a ridge line”.Deterioration of watershed takes place due to faulty and bad management through the activity of man and hi animals. h i i f d his i l
  3. 3. Causes of watershed Deterioration:These activities are:• Faulty agriculture, f l i l forestry and pasture d (Grass land) management leading to g g degradation of land.• Unscientific mining and quarrying quarrying.• Faulty road alignment and construction.• I d t i li ti Industrialization• Forest Fires• Apathy (less interest) of the people.
  4. 4. Results of watershed Deterioration D t i ti :• Less production from agriculture, forests, grass lands etc.• Erosion increases and decreases biomass production• Rapid siltation of reservoirs, lakes reservoirs and river beds.•LLess storage of water and l f d lowering of i f water table.• Poverty as a result of less food production.
  5. 5. WATERSHED DEVELOPMENTPossible range of treatment measures• Contour bunding• Contour trenching• Contour stone walls• Bench terraces• Land levelling• Summer ploughing
  6. 6. • Agro forestry with suitable species• Vegetative barriers• Ch k dams (Temporary and Check d (T d Permanent)• Retaining walls• Farm ponds and Percolation ponds• Renovation of existing water bodies and inlet channels
  7. 7. COMPONENTS OF WATERSHED DEVELOPMENT:• • Human Resource Development ( p (Community y Development) • Soil and Land Management • Water M W Management • Crop Management • Afforestation • Pasture/Fodder Development • Livestock Management •R lE Rural Energy MManagement • Farm and non-farm value addition activities• All these components are interdependent and interactive.
  8. 8. DEVELOPED WATERSHED
  9. 9. Methods for hill slopes p• CONTOUR TRENCHES AND STONE WALLS• BENCH TERRACING
  10. 10. CONTOUR TRENCHES AND STONEWALLS
  11. 11. •Suitable erosion control in S it bl i t li hills•Adopted for hill slopes >20% %•Continuous or interrupted
  12. 12. BENCH TERRACING
  13. 13. • It helps to bring sloping land into different level strips to enable cultivation. lti ti• It consists of construction of step like fields along contours by half cutting and half filling. g g• Original slope is converted into level fields The vertical and fields. horizontal intervals are decided based l d slope. b d land l
  14. 14. Methods for agric lt ral land agricultural• Check dam• Percolation pond• Micro catchments• Contour bund• Broad beds and furrows• Gully l G ll plugs• Tree plantation• Summer ploughing S l hi• Agro forestry• Vegetative barriers• Farm ponds
  15. 15. Check dam
  16. 16. • A low weir normally constructed across the y gullies• Constructed on small streams and long gullies formed by erosive activity of flood water• It cuts the velocity and reduces erosive activity• The stored water improves soil moisture of the adjoining area and allows percolation to recharge the aquifers h h if• Height depends on the bank height, varies from a 1 m t 3 m and l f to d length varies from th i f less than 3m to 10m
  17. 17. Percolation pond
  18. 18. • To improve the ground water recharge.• Shallow depression created at lower portions in a natural or diverted stream course• Located in soils of permeable nature p• Adaptable where 20-30 ground water wells for irrigation exist with in the zone of influence about 800 X 900 m
  19. 19. Micro catchments
  20. 20. • To conserve insitu moisture and reduce soil loss• Circular basin of one meter dia for level lands depending upon infiltration and rainfall• Ditches of size 5m x 5m with trees planted centre• Saucer basins / semi circular bunds with 2m diameter to a height of 15-20cm across the slope
  21. 21. Broad b d and furrowsB d beds d f
  22. 22. • To control erosion and to conserve soil moisture in the soil during rainy days• The broad bed and furrow system is laid within the field boundaries.• Conserves soil moisture in dry land.• Controls soil erosion erosion.• Acts as a drainage channel during heavy rainy days. d i h i d
  23. 23. Contour bund
  24. 24. • To intercept the runoff flowing p g down the slope by an embankment. embankment• It helps to control runoff velocity.• It can be adopted in light and medium textured soils.• It can be laid up to 6% slopes.• It helps to retain moisture in the field.
  25. 25. Gully plugs yp g
  26. 26. • Gully plug is one of the simple method of soil and water conservation. It plays an important role in soil and water conservation.• G lli are f Gullies formed d to erosion of top d due i f soil by the flow of rain water. In course of time, a gully assumes a big shape and erosion goes on increasing. To prevent erosion, barriers or plugs of different types of material are put across the gully gully, at certain intervals.
  27. 27. Tree plantation• Instead of uneconomical agriculture, g , farmers can grow grass in this hilly area and can use that as a fodder for cattle.• Farmers can go for dairy development if good quantity and quality of grass is available.
  28. 28. •For soil and water conservation this activity will help. Plantation on common l d will satisfy b i land ill ti f basic need of fuel wood.•Cheapest method for soil and water conservation
  29. 29. Summer ploughing p g g
  30. 30. •Main objective of field preparation is to control weeds•Facilitate easy sowing and to establish good seed soil contact•For easy absorption of moisture y p•To provide sufficient aeration•To i improve water holding h ldi capacity
  31. 31. Agro forestry g y• Agroforestry is an integrated approach of using th i t h f i the interactive ti benefits from combining trees and shrubs with crops and/or li t k h b ith d/ livestock.• It combines agricultural and forestry technologies to create more di h l i diverse, productive, profitable, healthy and sustainable l d i bl land-use systems.
  32. 32. Vegetative barriers g
  33. 33. •Vegetative barriers are also an g effective inter-terrace land treatment in place of earthen barriers.
  34. 34. Farm ponds p
  35. 35. • Rain water is harvested and stored• Used for storing water for longer duration duration.• Covered with polythene sheet to prevent evaporation. evaporation
  36. 36. Roof top rainwater harvesting p g• To recharge the wells (open and tube wells) particularly abandoned wells by a runoff y collection system.• Direct on-use of collected water on use if storage facility is available.
  37. 37. RECHARGE TUBE WELL • To directly feed depleted aquifers to fresh water from g ground surface so that the recharge is fast without any evaporation loss • Depth of recharge tube well depends on the present depth of bore wells in the area

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