Figure 1. (A) Freshwater provisioning index serving downstream human populations (FPIh) representing the number of downstream users supported by upstream water source area; (B) FPIh under Incident Human Water Security (HWS) threat; (C) FPIh under residual HWS threat reflecting threat remediation via Infrastructure Investments. Downstream population served under HWS threat denoted as low (blue), moderate (yellow) and high (red) with pie charts showing global totals.


Figure 4. Map depicts four threat development states where HWS threat on freshwater provisions supporting downstream users have: (red) stayed under persistent High threat, (orange) transitioned to High threat due to limited infrastructure investments, (green) improved from High to Low/Moderate threat as a result of investments in water infrastructure, or (blue) maintained relative health under Low/Moderate threat.


In this study we present a global framework that evaluates the capacity of upstream ecosystems to provide freshwater services to downstream populations addressing the following overriding questions:

How abundant and reliable are global freshwater provisions supporting humans?

The Freshwater Provisioning Index for humans (FPIh) shown in Figure 1 (A) represents a unique contribution to the existing array of global water indicators in that it moves beyond the traditional notion of water scarcity defined from a point-of-use perspective to mapping water provisions serving humans at their point-of-service in terms of both quantity and quality of this resource. This indicator is a direct measure of how ecosystem services support human water security explicitly mapping freshwater provisions relative to their downstream users identifying source areas with both the greatest natural potential to support humans and the greatest threat of impairment. The degree of impairment imposed on these freshwater provision areas via human-induced threats reveals that 82% of the world’s population is served by upstream areas exposed to high levels of threat. The highest threat to water provisions is found predominantly in the industrialized world as well as India and China; while developing nations experience moderate to high levels of threats to their water provisions [Figures 1 (B) and (C)].

How do different regions address threat abatement and what are the disparities?

The response and ability of different regions to abate freshwater ecosystem service impairment via investments in infrastructure aimed at improving human access to freshwater provisions reveals stark disparities between nations with economic resources to invest in abetment strategies and those without. Globally, 75% of the world’s population benefits from engineered remediation of highly impaired source areas. However, industrialized nations are far more effective at reducing threat to water sources serving their population (50-70% reduction in threat) than their developing nation counterparts (less than 20% reduction). As a result despite these overall global gains, more than 80% of the global population still experiences moderate levels of threat impacting their freshwater provisions and most of these are in the developing nations [Figures 1 (B) and (C)].

What are management implications of the chief findings?

To illustrate the potential for practical application of the FPIh indicator under real world considerations we develop a spatial typology of freshwater resource development states viewing the world in terms of the threats imposed on freshwater provisions combined with regional capacity to abate these impairments through infrastructure investments. This global mapping of threat development states (Figure 4) provides a synoptic-scale diagnosis of key water resource challenges informing several management strategies including: service area conservation, threat prevention, and green and grey infrastructure investments to resuscitate and/or continue sustainably managing upstream freshwater provisions. Water management strategies are presented to expand on the usefulness of the FPIh indicator and its potential applications as a practical tool for decision makers and managers in forward planning of freshwater resource management.

Banner image: The Danube River in Melk, Austria [photo courtesy of Darlene Dube].