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ASTM Standard Guide for • Defining Boundary Conditions in Ground-Water Flow Modeling (D 5609 - 94)

Specific Head or Dirichlet Boundary Type General-Specified-Head Boundary

-    head specified as a function of position and time Constant-Head Boundary

-    head specified as a function of position

Specific Flux or Neumann Boundary Type

-    flux specified as a function of position and time No-Flow Boundary

-    materiał of very Iow permeability Streamline Boundary

-    ground-water divide

Head Dependent Flux or Cauchy Type Boundary

-    flux varies dependent on head gradient between aquifer and boundary

Constant Flux Boundary

-    base of a confining layer after head is drawn down into confined/unconfined aąuifer

Head Dependent Boundary

-    ratę of evapotranspiration specified as a function of depth to a “cutoff ’ depth Free-Surface Boundary Type

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