Water is one of the most important elements for the health of an ecosystem. It is essential to all life on earth and is a limiting factor in economic and social development. Globally, freshwater resources are being over-exploited, polluted and degraded. Demands for water, for drinking as well as for development, are increasingly being made on systems which are already near the point of collapse. Water management policies that focus on both sustainable development and sustainable water use are more important than ever before in order to ensure that ecosystems are not permanently damaged.