This is also the underlying principle of carrying capacity
oriented indicators like the ecological footprint. They measure how
a society’s environmental resource demands are related to the
actual available land area and its environmental services like the
provision of biomass as in the EF, dissipation capacity for pollutants
as in the SPI or water provision as in the WSF. The WSF reveals how
much water is consumed in comparison to the available quantity of
freshwater delivered in a certain catchment area. If the footprint is
higher than the available environmental capacity, ecological
“overshoot” has occurred and the system is deemed as unsustainable
(Wackernagel and Rees, 1997). Unlike the Rees and Wackenagel
EF concept, the WSF has to use regional catchment specific
data about natural water flows and natural water requirements.
Using any carrying capacity oriented indicator for planning always
requires regionalized data so that concrete measures may be
derived from the use of the indicator.