The Upper Lempa River Basin spans Guatemala, Honduras and El Salvador in Central America. It is threatened by degradation of water resources from municipal, rural and industrial pollution, unsustainable land use changes, and over-extraction of water. These threats have resulted in water quality that does not comply with established standards, the eutrophication of lakes, fish kill events, unmet water demands during the dry season, and conflicts over water use. Climate change exacerbates these threats.
The United States Agency for International Development (USAID) awarded a five-year cooperative agreement to implement the Upper Lempa Watershed Project in March 2022 to Winrock International, in partnership with Tetra Tech ARD, SEI and the Center for Water Security and Cooperation. This project ended early in January 2025. The objective of the project was to work with institutions, municipalities and civil society to address the quantity, quality and reliability of water derived in the watershed.
Example of visualization illustrating the extent to which fecal coliform concentration in each sub-basin meet targets under a set of water management strategies selected by the dashboard user.
Screenshot from Proyecto CARL dashboard
As part of the project, SEI developed a WEAP model of the Upper Lempa Basin, which includes hydrological and water quality components. A dashboard was developed using Tableau to help decision-makers’ interpret data and model results across the basin’s seven main watersheds. The WEAP hydrological model and the dashboard allow decision-makers to evaluate the potential impact of climate change and of five management strategies on key outcome indicators. The five management strategies, identified through consultations with stakeholders, are: agricultural best management practices, management of agro-forestry land uses, improved municipal and coffee processing wastewater treatment, improved irrigation efficiency and reduced potable water losses.
The application of the WEAP model is proposed as a key tool in the management of resources in the Upper Lempa Basin, which, enhanced with the interactive visualization tool, has enormous potential to facilitate the participation of local stakeholders, improve the understanding of threats and vulnerabilities, and promote collaborative and sustainable management in a cross-border context.
Hydrologist Francisco Miguel Alvarenga, El Salvador Ministry of Environment and Natural Resources (translated)
El Salvador’s Ministry of Environment and Natural Resources (MARN) committed to being the main institution that updates, uses and shares the results of the WEAP model.
Partners in the Upper Lempa River Basin (CARL) project
Courtesy Doreen Brown Salazar
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