In response to growing concerns from private sector actors around water availability, water quality, climate change, and increasing demand, World Resources Institute developed Aqueduct Global Maps to help decision-makers identify areas with higher exposure to water-related risks. Aqueduct employs the composite index approach as a robust communication tool to translate hydrological data into intuitive indicators of water-related risks. 12 indicators were grouped into a framework identifying spatial variation in water risks for 15,006 subcatchments. The 12 global indicators (baseline water stress, interannual variability, seasonal variability, flood occurrence, drought severity, upstream storage, groundwater stress, return flow ratio, upstream protected land, media coverage, access to water, and threatened amphibians) were grouped into 3 categories of risk (physical quantity, quality, and regulatory and reputational risk) and 1 overall score. For 6 of the 12 indicators, an ensemble of time series estimators, spatial regression, and a sparse hydrological model was used to generate novel data sets of water supply and use. The remaining 6 indicators were adapted from existing publications. Aggregation methods were chosen to maximize transparency and communicability, and to allow for dynamic weighting to reflect different users’ sensitivities to water-related risks. Catchments with less than 0.012 m/m²/year of withdrawal and 0.03 m/m²/year of available blue water were masked out as “arid and low water use.” Resource Watch shows only a subset of the data set. For access to the full data set and additional information, see the Learn More link.
Aqueduct Global Maps 2.1
These global indicators are best suited for comparative analyses across large geographies to identify regions or assets deserving of closer attention, and are not appropriate for catchment or site-specific analyses. At the composite index level, the selection of aggregation methods is an inherently subjective process that creates value by simplifying complex phenomena. Validation of the composite index of water risk is a challenge because of the difficulty of collecting risk-event data. Other possible water-related risks also escape the index. The complex and qualitative nature of regulatory and reputational drivers of risk complicates researchers’ ability to create useful metrics. Barriers, such as inconsistent availability of data, as well as governments’ unwillingness or lack of capacity to collect and share water data, hamper the construction of consistent global water information. Water infrastructure is likewise undermeasured, as there are no published global data sets of major water transfer projects, infrastructural losses, or reservoir evaporation. Similarly, methods for evaluating freshwater ecosystem services such as flood attenuation and pollution control at the global scale remain underdeveloped.
Gassert, F., M. Luck, M. Landis, P. Reig, and T. Shiao. 2014. “Aqueduct Global Maps 2.1: Constructing Decision-Relevant Global Water Risk Indicators.” Working Paper. Washington, DC: World Resources Institute. http://www.wri.org/publication/aqueduct-globalmaps-21-indicators. Accessed through Resource Watch, (date). www.resourcewatch.org.