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Dr. P.K.MAJUMDAR Principal/Director Merchant Engineering College Mehsana, Gujarat, India

ADAPTIVE MODELLING OF WATERLOGGED GROUNDWATER REGIME. Dr. P.K.MAJUMDAR Principal/Director Merchant Engineering College Mehsana, Gujarat, India. ADAPTIVE GROUNDWATER MODELLING. RITUALS - TEXT BOOK KNOWLEDGE SPIRIT- SPOT PHILOSOPHY REALISATION - MODEL BEHAVIOUR

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Dr. P.K.MAJUMDAR Principal/Director Merchant Engineering College Mehsana, Gujarat, India

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  1. ADAPTIVE MODELLING OF WATERLOGGED GROUNDWATER REGIME Dr. P.K.MAJUMDAR Principal/Director Merchant Engineering College Mehsana, Gujarat, India

  2. ADAPTIVE GROUNDWATER MODELLING • RITUALS - TEXT BOOK KNOWLEDGE • SPIRIT- SPOT PHILOSOPHY • REALISATION - MODEL BEHAVIOUR • LIBERATION – CERTAINITY IN MODEL PREDICTIONS

  3. 1. DEVELOP SUITABLE GRID 2. INCORPORATE GRID-WISE PROPERTY 3. INPUT BOUNDARY CONDITIONS 4. INPUT STRESSES 5. SOLVE FOR GRIDS OTHER THAN BOUNDARY RITUALS

  4. 1. DEFINE CLEAR OBJECTIVES & SCOPE 2. CONCEPTUALISE MODEL WITH OBJECTIVE 3. CALIBRATE THE CONCEPTUAL MODEL 4. VALIDATE THE CALIBRATED MODEL 5. SIMULATION, PREDICTION OR REMEDIATION SPIRIT

  5. BASE CASE MODELS ARE NOT CALIBRATED MODELS • CALIBRATED PARAMETERS ARE NOT ALWAYS THE FIELD PARAMETERS • UNIQUE SOLUTION SATISFYING MOMENT & MASS IS DIFFICULT TO ACHIEVE • OBSERVED SCENARIOS ARE RESULT OF MORE THAN ONE STRESS • CONVOLUTION PERMITS THEORY OF LINEARITY & SUPERPOSITION • SEARCH AND SOLUTION TO AREA OF UNCERTAINITY • SENSITIVITY ANALYSIS IS SOLUTION FOR UNCERTAINITY REALISATION

  6. UNDERSTANDING OF NUMERICAL CALIBRATION/VALIDATION IN HYDROLOGIC/HYDROGEOLOGIC MODELS AS AGAINST THAT OF ANOLOG/DIGITAL HARDWARES • UNDERSTANDING OF STEADY AND UNSTEADY INFLUENCING STRESSES • UNDERSTANDING OF CAPACITY OF CALIBRATED MODEL PREDICTIONS • ASSIGNING STOCHASTIC RISK VALUE TO DETERMINISTIC OBJECTIVE FUNCTIONS • UNDERSTANDING OF NUMERICAL ERRORS AND ITS MINIMISATION • HENCEFORTH ENJOY MODELLING LIBARATION

  7. MODELOR’S ENVY: SCOPE LIMITED TO SOURCE/SINK TERM SUGGESTING CONJUNCTIVE USE PLANNING. IRRIGATION&DRAINAGE ENGINEER’S PRIDE: BLAMMING CANAL SEEPAGE & EXCESS-IVE IRRIGATION APPLICATION FACTS: LACALISED RISING OR NON-DEPLETING WATER TABLE CAUSED DUE TO: TOPOGRAPHY EXCESSIVE USE OF NUTRIENTS CAUSING GRADUAL REDUCTION IN LOCAL HYDRAULIC CONDUCTIVITY NON-CONSUMPTIVE IRRIGATION APPLICATION WATERLOGGED GROUNDWATER REGIME

  8. Location Map of the Dharoi RBC command area

  9. RAINFALL Temperature varies from 44°c (summer) to 4°c (winter). Humidity during monsoon reaches to 95 % or even more. :Average evaporation losses (Mcm) in Dharoi reservoir Dharoi Command Soil Properties in pre and post Irrigation Era

  10. DIGITIZED MAP TOPOGRAPHY (Kavalanekar et al.,1992)

  11. AVERAGE SLOPE WATERLOGGED AREA SURFACE CONTOURS SWIFT GRID FOR PERCHED AQUIFER MODEL FLOW AFTER DAM FLOW BEFORE DAM

  12. SW-GW INTERACTIONS VISNAGAR VADNAGAR DHAROI RESERVOIR Vs GWL DENAP

  13. POINT WATERLOGGING AS WELL CLOGGING Majumdar, P. K., Sekhar, M., Sridharan K., Mishra, G. C. Numerical simulation of groundwater flow with gradually increasing heterogeneity due to clogging, Journal of Irrigation and Drainage Engineering, Vol. 134, No. 3, May/June 2008, pp. 400-404

  14. EFFECT OF GRADUALLY INCREASING CLOGGING 1 2 4 3 Head buildups in (1) Recharge well, (2) Observation well, (3) D/s Observation well, (4) U/s Observation well

  15. HYDROGEOLOGY k PRE & POST MONSOON GWL STEADY STATE GWL TREND

  16. STEADY STATE CALIBRATION (P/w+V2/2g+Z) Match OBSERVED AVERAGE HYDRAULIC GRADIENT = 0.3 m/km COMPUTED AVERAGE HYDRAULIC GRADIENT = 0.23 m/km k MODEL RESULT AQUIFER PARAMETERS

  17. 0.01 0.25 0.065 0.105 32.5 10 Sy 97.5 130 65 10 RECHARGE (mm/yr) RAINFALL + HR SUPPLY

  18. INITIAL WL 25 10 80 180 OBSERVED WL DRAFT (mm/yr)

  19. BASE CASE SCENARIO

  20. IF-WHAT RUN RESULTS

  21. CONCLUSION & SUGGESTION • REGIONAL GROUNDWATER MODELLING IS ALWAYS ADAPTIVE IN CHARACTER • PLAYING WITH SOURCE/SINK TERM IN ISOLATION IS NOT ALWAYS APPROPRIATE TO MODEL WATERLOGGING • WATERLOGGING, WHEN CAUSED BY TOPOGRAPHY, NEEDS ATTENTION DURING MODEL GRID DEVELOPMENT • WATERLOGGING, WHEN CAUSED DUE TO CHOKING OF PORES, NEEDS CONSIDERING GRADUALLY DECREASING HYDRAULIC CONDUCTIVITY • BASE CASE MODEL CAN PROJECT THE REDUCTION IN WATER APPLICATION TO AVOID WATERLOGGING

  22. THANK YOU

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