Within a groundwater system, the interface between regions of different hydraulic characteristics such as porosity, storativity (see storage coefficient), conductivity (see permeability), or transmissivity. For example, when modelling groundwater systems or carrying out pumping tests, workers must make judgements regarding the homogeneity of those systems. Distinct and marked changes in the hydraulic characteristics (e.g. where an aquifer abuts an aquiclude) may require marking as hydraulic boundaries.
Subjects: Earth Sciences and Geography.