Partitioning evapotranspiration into green and blue water sources in the conterminous United States

Scientific Reports
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Abstract

In this study, we combined two 1 km actual evapotranspiration datasets (ET), one obtained from a root zone water balance model and another from an energy balance model, to partition annual ET into green (rainfall-based) and blue (surface water/groundwater) sources. Time series maps of green water ET (GWET) and blue water ET (BWET) are produced for the conterminous United States (CONUS) over 2001–2015. Our results indicate that average green and blue water for all land cover types in CONUS accounts for nearly 70% and 30% of the total ET, respectively. The ET in the eastern US arises mostly from GWET, and in the western US, it is mostly BWET. Analysis of the BWET in the 16 irrigated areas in CONUS revealed interesting results. While the magnitude of the BWET gradually showed a decline from west to east, the increase in coefficient of variation from west to east confirmed greater use of supplemental irrigation in the central and eastern US. We also established relationships between different hydro-climatology zones and their blue water requirements. This study provides insights on the relative contributions and the spatiotemporal dynamics of GWET and BWET, which could lead to improved water resources management.

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Publication type Article
Publication Subtype Journal Article
Title Partitioning evapotranspiration into green and blue water sources in the conterminous United States
Series title Scientific Reports
DOI 10.1038/s41598-017-06359-w
Volume 7
Year Published 2017
Language English
Publisher Nature
Contributing office(s) Earth Resources Observation and Science (EROS) Center
Description 6191, 12 p.
Country United States
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