2008:57 Discrete Feature Model (DFM) User Documentation

This manual describes the DiscreteFeature Model (DFM) software package for modelling groundwater flow and solute transport in networks of discrete features. A discretefeature conceptual model represents fractures and other waterconducting features around a repository as discrete conductors surrounded by a rock matrix which is usually treated as impermeable. This approximation may be valid for crystalline rocks such as granite or basalt, which have very low permeability if macroscopic fractures are excluded. A discrete feature is any entity that can conduct water and permit solute transport through bedrock, and can be reasonably represented as a piecewiseplanar conductor. Examples of such entities may include individual natural fractures (joints or faults), fracture zones, and disturbedzone features around tunnels (e.g. blastinginduced fractures or stressconcentration induced "onion skin" fractures around underground openings).