Hydraulic behavior and contaminant transport in multiple porosity media

The hydraulic behavior and contaminant transport of aquifers containing dis tinct families of fractures are investigated by using the multiple porosity continuum model. We consider that the conditions are such that a horizonta l 2D flow takes place. By writing the continuity of mass (including exchang e terms between the various families of fractures) and Darcy's law for each family of fractures, macroscopic equations for both confined and unconfine d flow are obtained. A classification procedure and geometrical idealizatio n of the individual fractures for each family is proposed which enables the calculation of the exchange coefficients. Equations for the description of the contaminant transport in the field scale for both confined and unconfi ned aquifer are developed. It turns out that the adequate formulation of th e macroscopic equations and their sink-source term depends on whether the a quifer investigated is confined or unconfined, and also on the value of an nondimensional parameter describing the transfer process at the microscopic scale (connection Peclet number). Numerical investigation of representativ e problems offers some insight into the behavior of double and triple poros ity aquifers.