Exploring Past, Present, and Future Water Availability Regionally, Globally

January 16, 2018

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Exploring Past, Present, and Future Water Availability Regionally, Globally
Main inputs and outputs of Xanthos hydrologic model to study runoff generation and river routing.

The Science

Freshwater resources are finite, unevenly distributed, and changing through time.  The demand—and competition—for water is expected to grow both in the United States and in the developing/developed world.  To examine the connection between supply and demand and resulting regional and global water stresses, a team developed Xanthos. The open-source hydrologic model is available for free and helps researchers explore the details and analyze global water availability.

The Impact

Researchers can use Xanthos to examine the implications of different climate, socioeconomic, and/or energy scenarios over the 21st century. They can then assess the effects of the scenarios on regional and global water availability. Xanthos can be used in three different ways. It can operate as an independent hydrologic model, driven, for example, by scenarios. It can serve as the core freshwater supply component of the Global Change Assessment Model, where multiple sectors and natural systems are modeled simultaneously as part of an interconnected, complex system. Further, it can be used by other integrated models and multi-model frameworks that focus on energy-water-land interactions.


Xanthos, an open-source hydrologic model written in Python, simulates historical and future global water availability on a monthly time step at a spatial resolution of 0.5 geographic degrees. Scientists designed Xanthos to be extensible and used by researchers who study global water supply, including those researchers who work with the Global Change Assessment Model, also developed at Pacific Northwest National Laboratory. Validated with global data sets, Xanthos includes modules for calculating potential evapotranspiration, runoff generation, and stream routing. Researchers are able to customize Xanthos' configuration file to specify model inputs, outputs, and parameters. Xanthos can provide historical observations and future estimates of renewable freshwater resources in the form of total runoff. The model's modular and flexible structure is intended to promote community engagement, enabling users to integrate their own research through extensible modules.


BER Program Manager
Bob Vallario
Integrated Assessment Research
U.S. Department of Energy

PNNL Contact
Mohamad Hejazi
Pacific Northwest National Laboratory


The U.S. Department of Energy, Office of Science, Biological and Environmental Research supported this research as part of the Integrated Assessment Research program.


X. Li, C.R. Vernon, M.I. Hejazi, R.P. Link, L. Feng, Y. Liu, and L.T. Rauchenstein, "Xanthos – A Global Hydrologic ModelExternal link." Journal of Open Research Software 5(1), 21 (2017). [DOI: 10.5334/jors.181]

Related Links

Download the software: https://github.com/JGCRI/xanthosExternal link

Highlight Categories

Program: BER, CESD

Performer/Facility: DOE Laboratory