BASEFLOW SEPARATION BASED ON ANALYTICAL SOLUTIONS OF THE BOUSSINESQ EQUATION

A technique for baseflow separation is presented based on similarity s olutions of the Boussinesq equation. The method makes use of the simpl ifying assumptions that a horizontal impermeable layer underlies a Dup uit aquifer which is drained by a fully penetrating stream. The value of the baseflow maximum as well as the baseflow recession hydrograph c an be estimated by fitting the analytical solutions of the Boussinesq equation to the observed discharge values for individual flood events. For the rising limb of the baseflow hydrograph a linear function is a ssumed for simplicity. The method is first demonstrated on three water sheds for a total of five flood events and extensively applied over a three year period for the Mahantango Creek, Pennsylvania watershed. Th e proposed method reduces some of the subjective aspects long associat ed with baseflow separation techniques. (C) 1998 Elsevier Science B.V.