Introducing the WASH Flows analytical tool

The Stockholm Environment Institute has developed WASH Flows, a Microsoft Excel-based tool that links household-level WASH data with watershed-scale modelling, such as WEAP. By bridging the gap between WASH services and Integrated Water Resource Management (IWRM), the tool allows users to estimate service levels, identify vulnerable communities, and model the impact of interventions on water balance and quality. A case study in the Tupiza watershed in Bolivia demonstrated the tool's ability to establish a service baseline—revealing significant gaps in safely managed water (25%) and sanitation (4%)—and to evaluate the effectiveness of proposed drinking water and decentralized sanitation systems in increasing drought resilience.

• WASH Flows is designed to bridge the traditional governance gap between WASH services and watershed management by connecting household-level data to watershed-level flows within a single analysis framework.
• The tool operates via Microsoft Excel and can function as a standalone tool or be coupled with watershed-scale modelling software like WEAP (Water Evaluation and Planning) to analyze the reliability of water sources and the impact of wastewater on downstream water bodies.
• WASH Flows enables the estimation of service levels, water demand, and wastewater generation based on household infrastructure, allowing for the prioritization of interventions in vulnerable communities.
• A case study in the Tupiza watershed in Bolivia, covering 2,309 square kilometres and approximately 47,000 people, established a baseline showing that only 25% of rural households have safely managed water and 4% have safely managed sanitation.
• In the Tupiza case study, the tool identified that 22% of rural communities have access to basic hygiene services and estimated that wastewater discharge produces biological oxygen demand (BOD) between 10 and 15 kg per inhabitant per day.
• Modelling in the Tupiza watershed indicated that implementing community drinking water systems and decentralized sanitation systems would reduce water-access vulnerability during droughts and increase overall WASH coverage.

APA

Claure, P., Esquivel, N. N., Liera, C., Trujillo, A. S., & Escobar, M. (2023). Introducing the WASH Flows analytical tool. Stockholm Environment Institute. https://www.sei.org/wp-content/uploads/2023/02/wash-flows-watershed-management-tool.pdf

Chicago

Claure, Pamela, Nhilce N. Esquivel, Carla Liera, Adriana Soto Trujillo, and Marisa Escobar. Introducing the WASH Flows analytical tool. Stockholm Environment Institute, 2023. https://www.sei.org/wp-content/uploads/2023/02/wash-flows-watershed-management-tool.pdf.

Wikipedia

{{cite report |last1=Claure |first1=Pamela |last2=Esquivel |first2=Nhilce N. |last3=Liera |first3=Carla |last4=Trujillo |first4=Adriana Soto |last5=Escobar |first5=Marisa |title=Introducing the WASH Flows analytical tool |publisher=Stockholm Environment Institute |date=February 2023 |url=https://www.sei.org/wp-content/uploads/2023/02/wash-flows-watershed-management-tool.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{claure2023introducing, author = {Claure, Pamela and Esquivel, Nhilce N. and Liera, Carla and Trujillo, Adriana Soto and Escobar, Marisa}, title = {{Introducing the WASH Flows analytical tool}}, institution = {Stockholm Environment Institute}, year = {2023}, month = feb, url = {https://www.sei.org/wp-content/uploads/2023/02/wash-flows-watershed-management-tool.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }