The matrix supports the intuitive and iterative “playing with the
figures” to assess water supply scenarios based on linking together
the availability of certain water qualities and the quantitative and
qualitative water demand on a strategic level. Visioning and
scenario building can be approached both from the demand side
and the supply side: demand-centred approaches would ask
questions such as: “what catchment areas by land use type do we
need for a given water demand?” The supply-focused approach
would ask: “how much water can we collect in our regional water
supply in a sustainable way?” The WSF helps answer such questions
in an integrated way and could be employed to iteratively
optimise the water supply strategies.