sentences:  The discharge potential is a potential in groundwater mechanics which links the physical properties, hydraulic head, with a mathematical formulation for the energy as a function of position.The discharge potential, formula_2 [L3·T−1], is defined in such way that its gradient equals the discharge vector.formula_3
  
  formula_4
  
  Thus the hydraulic head may be calculated in terms of the discharge potential, for confined flow as
  
  formula_5
  
  and for unconfined shallow flow as
  
  formula_6
  
  where
  
  As mentioned the discharge potential may also be written in terms of position.