NETFLO is a model to simulate steady-state three-dimensional ground-water flow in a heterogeneous medium using an equivalent network of series and parallel flow members. Where the stratigraphy does not suggest a particular network configuration, a network may be specified along principal stream tubes specified with a more general three-dimensional ground-water flow code. A special application of the network topology is to analyze flow through a system of discrete fractures. The algorithm of NETFLO is based on the application of Darcy's Law along each member (or branch) of the network and conservation of mass at each node. The boundary conditions may be either of prescribed pressure or take the form of sources/sinks at the boundary nodes. The code is mathematically equivalent to a set of one-dimensional finite line elements with linear basis function. NETFLO outputs pressure at all nodes and velocities and fluxes in all members. Furthermore, the code determines all possible flow paths from the node representing the contaminant source (e.g., a nuclear waste repository) to the discharge node, and the pertinent mean flow, retardation factor, time of travel and path length for each path.

NETFLO runs in batch mode and creates text output files. Example data sets are provided, which can be copied and edited with a text editor for individual problems. NETFLO is a public domain program distributed on DOS-formatted disks containing source code, executable image, and example data sets. The program documentation includes installation instructions and user's manual.

SYSTEM REQUIREMENTS

Intel 80i86-based computer, math coprocessor, 640 Kb RAM, DOS 3.0 or higher, at least 1 Mb free disk space for programs, source files, and example data files and output files.

Authors: B.S. RamaRao and S.B. Pahwa (Intera Environmental Consultants).