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Understanding Water Science: Groundwater Dynamics and Influencing Factors

Join Dr. S.V. Govardhan Das for an insightful session on water science at Aalankrita Resort, Hyderabad. This presentation will cover vital aspects of the Earth's water cycle, focusing on groundwater dynamics. Learn about the various factors controlling groundwater quantity, such as geology, rock type, porosity, permeability, and human activities including deforestation and mining. Discover how these elements impact water quality and availability, crucial for sustainable management. Don't miss this opportunity to deepen your understanding of essential water science concepts.

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Understanding Water Science: Groundwater Dynamics and Influencing Factors

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  1. A quick look at Water science Date : 31 July 2007Time : 14.00 to 15.30 hrs.Venue : Aalankrita Resort, HyderabadTopic : A quick look at Water scienceFaculty :Dr. S. V. Govardhan Das

  2. Scheme of presentation • Earth’s Water Cycle or Hydrological cycle • Factors controlling groundwater quantity • Factors controlling groundwater quality

  3. Factors controlling groundwater quantity • Geology • Rock type • Texture – Porosity • Permeability • Structure and Tectonics • Recharge rate • Aquifer type • Elevation • Rainfall • Well spacing • Human activity • Deforestation • Mining • Damming • Overdraft

  4. Factors controlling groundwater quantity Texture - Porosity

  5. Factors controlling groundwater quantity Permeability

  6. Factors controlling groundwater quantity Structure • Weathering • Fracturing • Magmatic activity • Folding • Faulting

  7. Factors controlling groundwater quantity Structure Weathering: • Soil • Loose material, above the parent rock • Formed over period of millions of years • Due to the action of geomorphic agents: • wind, • water, • sea action • temperature

  8. Factors controlling groundwater quantity Structure Fracturing • Layer between the weathered zone and parent rock • Tectonic activities • Magmatic activity • Volcanic activity • Increase/decrease in pressure regimes • Increase/decrease in thermal regimes

  9. Factors controlling groundwater quantity Aquifer type

  10. Factors controlling groundwater quantity Elevation • In case of unconfined/semi-confined aquifers • Higher elevations: recharge areas: more percolation • Low lying areas: discharge areas: base-flow • Very important in siting shallow dug-wells

  11. Factors controlling groundwater quantity Rainfall • Major source of groundwater recharge • Amount • Annual distribution • Temperature determines the percentage of evapotraspiration, percolation and run-off • Intensity • For producing run-off • For percolation • No. of rainy days

  12. Factors controlling groundwater quantity Recharge rate (Source: GEC 97)

  13. Factors controlling groundwater quantity Human activity:Deforestation • Cutting of trees exposes the soil • Natural action of geomorphic agents speeded up • Wind blows away soil at faster rates • Water takes away sediments at faster rates • Sea currents wash away the soil at faster rates • Soil heated up and cooled at faster rates • Loosening of soil material takes place at faster rates • Run-off at faster rates: Flash floods • Reduced percolation rate • Amount of percolation reduced

  14. Factors controlling groundwater quantity Human activity:Mining • Open cast mining augments recharge • Underground mining creates vacuums beneath ground • Land subsidence • Groundwater seeps into the mine: dangerous • Increased sub-surface runoff • Draining away of groundwater in adjoining areas • Major mining areas: weak structures collapse • Mild tremors: opening/closing of fractures • Drying up of fracture zones • Recharge of deep aquifer zones, directly • Upper aquifer zones in the vicinity go dry

  15. Factors controlling groundwater quantity Human activity: Damming • Dams are constructed across big rivers • Impoundment of water behind dam • Augments groundwater recharge process, in vicinity • Canal system (unlined): augments recharge, in vicinity • Water pressure can cause mild tremors • Mild tremors: opening/closing of fractures • Drying up of fracture zones • Recharge of deep aquifer zones, directly • Drying up of aquifers down stream • Land subsidence

  16. Factors controlling groundwater quantity Human activity: Overdraft • Lowering of water table • Increase in investment for tapping groundwater • Zone of Aeration increases • Base flows disappear making stream ephemeral • Drying up of fracture zones • Groundwater Mining • Mild tremors: opening/closing of fractures • Land subsidence • If the aquifer is artificially recharged mild tremors • Case of Vijayawada

  17. Factors controlling groundwater quantity Recharge – Draft – Balance

  18. Factors controlling groundwater quantity Recharge – Draft – Balance

  19. Factors controlling groundwater quantity Recharge – Draft – Balance

  20. Factors controlling groundwater quantity Recharge – Draft – Balance

  21. Factors controlling groundwater quantity Recharge – Draft – Balance

  22. Factors controlling groundwater quantity

  23. Factors controlling groundwater quality • Geology • Rock type • Texture – Porosity • Permeability • Structure • Leachability • Aquifer type • Human activity • Industrial pollution • Waste disposal • Sewage disposal • Fertilizer/pesticide/manure pits

  24. Thank U

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