Hydrological Balance

Hydrological Balance

1. Determination of groundwater recharge

   • The most relevant parameters in hydrogeology but also the most difficult to estimate
   • Geochemical
   • Physical
   • Climatic methods.
     • P= ETR+R+I
       • Method used for the hydrological balance.  P = precipitation  ETR = evapotranspiration I = groundwater recharge R = surface flow
       • ETR determined by the Coutagne method
       • R. by the Tixéront-Berkaloff method

2. Estimation of potential evapotranspiration and actual evapotranspiration

   • Thornthwaite proposed an expression for estimating FTE considering only the monthly temperature
   • • T: average monthly temperature in °C.  I: annual thermal index.i: monthly thermal index. F: correction coefficient, function of latitude and given month.
     • • Here, λ= 1/(0,8+ 0,145T)
         • T: mean annual temperature in °C; P: mean annual precipitation in m
         • Considerations for the application to the formula:

3. Estimate of runoff

   • • Tixéront and Berkaloff established a relationship whose simplified form gives runoff
     • With R: runoff in mm; P: mean annual precipitation in mm; ETP: average annual potential evapotranspiration calculated by the Thornthwaite method in mm

4. Estimation of infiltration

   • Known parameters for the calculation 

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