ABSTRACT

This chapter focuses on learning to draw a flow net in situations where isotropic conditions may be assumed or, where layers are present that vary by more than two orders of magnitude. A flow net constitutes a sketched representation of the flow paths taken by water molecules in moving through a soil. The "grid" of a flow net is comprised of flow lines and equipotential lines. Flow nets may be sketched in either plan view or cross-sectional view. Plan-view nets are used less frequently than cross-sectional nets, but may be of value in revealing important regional and subregional flow trends, including the critical paths likely to be followed by migrating contaminants from landfills and the locations of spills. The following conditions are implicit in the use of flow nets: all geologic materials are saturated; and flow is laminar and Darcy's law applies.