New WEAP PlugIn calculates water stress, disaggregated by sub-basin

The Stockholm Environment Institute (SEI) describes a new PlugIn for the Water Evaluation and Planning (WEAP) software, developed in collaboration with the Food and Agriculture Organization of the United Nations (FAO). The tool calculates water stress disaggregated by catchment area and sub-basin, assisting countries in meeting Sustainable Development Goal (SDG) Indicator 6.4.2.

• A new PlugIn for the Water Evaluation and Planning (WEAP) software has been developed by the Food and Agriculture Organization of the United Nations (FAO) and the Stockholm Environment Institute (SEI) to calculate water stress at the sub-basin level. This tool is designed to help countries develop strategies to meet Sustainable Development Goal (SDG) Indicator 6.4.2, which measures water stress to secure clean water and sanitation globally.
• The tool utilizes specific definitions for water scarcity, water demand satisfaction, and environmental flow (EF). Water stress is calculated as the ratio of total freshwater withdrawals (TFWW) to the difference between total renewable freshwater resources (TRWR) and environmental flow requirements (EFR).
• To standardize calculations for SDG 6.4.2 when minimum environmental flows are not established, the tool uses the Flow Duration Curve (FDC) Shift method. This method adjusts environmental flows based on the ecological management class of a river, applying stricter flows to rivers in natural or moderately modified conditions compared to largely modified ecosystems.
• Application of the tool to the Senegal River basin demonstrates that water stress varies significantly by sub-basin and year. In a wet year (2021), water stress was below 10% in the upstream Bakoye, Kolombine, Faleme, and Karakoro basins, but reached 66% in the Bafing River basin and exceeded 70% in lower portions of the Senegal River below Bakel.
• Simulations in the Senegal River basin indicate that reducing canal losses from an average of 35% to 15% leads to a clear decrease in water stress. However, high population growth scenarios (4% per year) are projected to increase water stress and decrease water demand satisfaction, particularly for Dakar.
• As of July 2023, the PlugIn has been tested in four cases: a pilot project in the Cap Matifou area of Algeria, a model of the Medjerda River, a model of Rwanda, and a simplified model of the Senegal River.
• The development team recommends four criteria for models calculating disaggregated water stress: selecting an entire basin rather than a subset; modeling external basins if they provide or receive significant freshwater resources; including all significant water supplies and demands (including external ones); and avoiding the selection of small catchments unless they are major freshwater sources.

APA

Joyce, B., & Salazar, D. (2023). New WEAP PlugIn calculates water stress, disaggregated by sub-basin. Stockholm Environment Institute. https://www.sei.org/wp-content/uploads/2023/12/sei2023.062-weap-plugin-water-stress-corrected.pdf

Chicago

Joyce, Brian, and Doreen Salazar. New WEAP PlugIn calculates water stress, disaggregated by sub-basin. Stockholm Environment Institute, 2023. https://www.sei.org/wp-content/uploads/2023/12/sei2023.062-weap-plugin-water-stress-corrected.pdf.

Wikipedia

{{cite report |last1=Joyce |first1=Brian |last2=Salazar |first2=Doreen |title=New WEAP PlugIn calculates water stress, disaggregated by sub-basin |publisher=Stockholm Environment Institute |date=December 2023 |url=https://www.sei.org/wp-content/uploads/2023/12/sei2023.062-weap-plugin-water-stress-corrected.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{joyce2023new, author = {Joyce, Brian and Salazar, Doreen}, title = {{New WEAP PlugIn calculates water stress, disaggregated by sub-basin}}, institution = {Stockholm Environment Institute}, year = {2023}, month = dec, url = {https://www.sei.org/wp-content/uploads/2023/12/sei2023.062-weap-plugin-water-stress-corrected.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }