In order to develop our ideas, the article is structured in the
following way: Section 2 lays out the conceptual principles behind
our WSF model, Section 3 describes the method, and Section 4 quantitative sense. In the case of quality, there is a minimum
quality of water that is needed to sustain ecosystem health, followed
by a sliding scale of various acceptable qualities up to a limit
that could be considered the very best possible quality. This same
scale can be used to assess quantitative requirements where there
is an optimal amount of water that is necessary for ecosystem
health (environmental flows) or immediate human needs.