News Release

Forest science benefits water resources, aids developing countries

December 3, 2013

U.S. Forest Service researchers are expanding a web-based planning tool designed to project future water availability in the United States, Mexico, and Africa.

The Water Supply Stress Index (WaSSI) model predicts how climate, land use, and human population changes may impact forests’ ability to provide goods and services, called ecosystem services, including water supply, carbon sequestration, recreation, and wildlife habitat.

Water availability is important to current and future land management planning and human well-being. Natural resource managers use WaSSI to visualize the effects of management options on ecosystem productivity, making informed water supply-related decisions for short- and long-term strategies to sustain ecosystem services.

The enhanced online WaSSI tool features: 1) English and Spanish user guides, 2) geographically relevant maps in user-friendly formats; and 3) expanded climate and land use change options, information, and future scenarios for the eastern African countries Rwanda and Burundi.

“Deforestation and climate change pose significant threats to water resources in the populous Rwanda region in spite of ongoing international conservation efforts,” says Ge Sun, U.S. Forest Service Eastern Forest Environmental Threat Assessment Center research hydrologist and lead WaSSI developer. “Expanding the model’s capabilities in developing countries helps refine conservation strategies in areas responding to population growth, extreme weather, and other human influences impacting water resources.”

Created in 2005, WaSSI is a collaborative effort among federal agencies, universities, and non-governmental organizations. The multi-disciplinary WaSSI development team has conducted workshops in Mexico and Africa and continues to improve the tool’s application throughout the United States.

For additional information and to begin using the tool, please visit