This page provides a brief overview of the methodology behind Aqueduct’s water risk maps. For a more detailed look at how risk scores are calculated and mapped, please refer to the summary methodology document (PDF, 11 pages, 678 Kb)

Indicator Framework

The Water Risk Framework shown above is the foundation of Aqueduct’s database of water information. It includes 14 indicators, grouped in 3 categories of water risk to businesses: Physical Risk (QUANTITY), Physical Risk (QUALITY) and Regulatory & Reputational Risks. The indicators were chosen based on their relevance to company \ decision-makers as well as on data availability in the public domain. Aqueduct’s Water Risk Framework focuses on measuring business risks posed by water, thus drawing out elements that are relevant to business and financial institutions alikeencouraging the private sector to collaborate with public sector leaders to create more equitable, efficient, and sustainable water resources management policies and legislation.

The 3 categories of water-related business risk were determined by WRI in collaboration with industry experts, financial analysts, and water specialists, and include:

• Physical Risks (QUANTITY): capture a measure of the risks to business driven by having access to too little water (scarcity) or threatened by too much water (floods);

• Physical Risks (QUALITY): capture a measure of the risks to business driven by water that is unfit for use due to pollution.

• Regulatory and Reputational Risks: capture a measure of the risks to businesses driven by unstable regulatory environments and social tensions and conflicts around water.

To learn more about individual indicators, how they are calculated, and how they contribute to an overall picture of water risk, download the detailed indicator descriptions table (PDF, 3 pages, 131 Kb)

Calculating and Mapping Water Risk Scores

In order to create basin level water risk maps, data is collected for all of the indicators in the framework above (see below for more on data sources and collection). The process of calculating and mapping water risk scores based on this data follows six distinct steps:

1. Defining geographic units of analysis: the basin is divided up into smaller units according to administrative and hydrological boundaries.

2. Calculating indicator values: the value for each indicator is calculated for each geographic unit, according to the methods laid out in the indicator description table (PDF, 3 pages, 131 Kb) .

3. Adjusting for outliers: extremely high and low values are adjusted for, to limit the impact a single data point can have on overall water risk scores.

4. Normalizing and risk scoring: to enable comparing and combining data measured in many different units, indicator values are transformed into standardized risk scores.

5. Weighting indicators: each indicator is assigned a different weight to reflect its priority and importance in calculating overall water risk. These weights can be adjusted by the user to reflect their unique risk profile.

6. Aggregating water risk scores: all of the indicators are combined together according to their respective weights to give a broad overall picture of water risk.

Each of these steps is described in detail in the summary methodology document (PDF, 11 pages, 678 Kb)

Data Sources

To calculate the value of the indicators and insure the integrity of the results, WRI is committed to using the most robust and widely accepted datasets in the public domain. WRI undergoes a rigorous data selection and validation process that relies heavily on external expert consultation. Expert consultation is carried out by convening basin-specific Advisory Groups that provide advice and recommendations on the selection of datasets, as well as detailed information on the data limitations and anomalies. A basin Advisory Group is composed in its entirety of river basin experts – from governments, NGO’s, and academic institutions – many of whom are experienced researchers or data providers. Data sources are selected from a wide range of organizations (see below) based on three criteria:

• Granularity: when available, local or sub-national data sources are selected to provide maximum accuracy and relevance;

• Replicability: mainstream publicly available data sources are selected to ensure the Aqueduct Water Risk Atlas can be replicated; and

• Completeness: sources with adequate spatial and temporal coverage are selected to allow consistent mapping across the basin

Data Sources: China’s Yellow River Basin

For a list of the specific data sources used to generate the Yellow River Basin water risk maps (in English and Chinese), please refer to the Yellow River Basin Data Sources Summary. (PDF, 4 pages, 657 Kb) For recommendations on updated or improved data sources for the Yellow River Basin please contact Tien Shiao at tien.shiao@wri.org.

Data Sources: Southern Africa’s Orange-Senqu Basin

For a list of the specific data sources used to generate the Orange-Senqu River Basin water risk maps, please refer to the Orange-Senqu Basin Data Sources Summary. (PDF, 3 pages, 292 Kb) For recommendations on updated or improved data sources for the Yellow River Basin please contact Paul Reig at paul.reig@wri.org.

Data Sources: Global Water Stress Maps

Global water risk maps are available thanks to the generous contribution of the Coca-Cola Company. To learn more about the global water risk maps and how they are generated, download the Global Water Stress Map Interpretive Guidelines (PDF, 18 pages, 729 Kb)

WRI and ISciences will update and refresh the global maps in 2012.

_{Disclaimer: Use of and/or reliance on any data and/or information included on the Aqueduct website – including data and/or information provided by The Coca-Cola Company to the Aqueduct project – is at the user’s own risk. The World Resources Institute and the supporters of the Aqueduct project, including The Coca-Cola Company, make no claim, representation, or warranty as to the accuracy of the data and information included on the Aqueduct website. The World Resources Institute and the supporters of the Aqueduct project, including The Coca-Cola Company, disclaim any responsibility associated with use of and/or reliance on any of the data and/or information included on the Aqueduct website and will not have any liability of any kind relating to such use and/or reliance. The Coca-Cola Water Risk Data is used in connection with the Aqueduct Project by WRI pursuant to a royalty-free license from Coca-Cola Company. The Coca-Cola Company is a proud supporter of the Aqueduct Project.}