The amount of water that can be used on a sustainable basis is
not only dependent on rainfall and water inflows in a region, but
also on the land use and the water quality either (1) provided by
a certain area or (2) demanded by a certain use. Analogous to the
consumption-land use matrix of the original footprint model
(Wackernagel and Rees, 1993) or the energy matrix of the energy
footprint (Stöglehner, 2003), the results can be expressed in a WSF matrix
relating level and types of water demand to the attendant
land use areas (and rainfall levels) within the catchment. The land
use of the catchment area can be used as an indicator for water
quality. For instance, forests normally procure higher water qualities
than agricultural land. Different water qualities can be used for
different purposes: water for gardening or process water in