Groundwaterscapes: A global classification and mapping of groundwater’s large-scale socioeconomic, ecological, and Earth system functions

Xander Huggins , Tom Gleeson , Karen G. Villholth, Juan Carlos Rocha , James S. Famiglietti

Groundwater is a dynamic component of the global water cycle with important social, economic, ecological, and Earth system functions. We present a new global classification and mapping of groundwater systems, which we call groundwaterscapes, that represent predominant configurations of large-scale groundwater system functions. We identify 18 groundwaterscapes, which offer a new lens to conceptualize, study, model, and manage groundwater. Groundwaterscapes are empirically derived using a novel application of sequenced self-organizing maps and capture grid cell level (5 arcminute) patterns in groundwater system functions, such as groundwater-dependent ecosystem type and density, storage capacity, irrigation, and integrated groundwater management. All large aquifer systems of the world are characterized by multiple groundwaterscapes, highlighting the pitfalls of treating these groundwater bodies as lumped systems in global assessments. We evaluate the distribution of Global Groundwater Monitoring Network wells across groundwaterscapes and find that industrial agricultural regions with strong groundwater management are disproportionately monitored, while several groundwaterscapes have next to no monitoring wells at all. This disparity undermines the ability to understand system dynamics across the full range of settings in which groundwater is found. We argue groundwaterscapes offer a conceptual and spatial tool to guide model development, hypothesis testing, and future data collection initiatives to better understand groundwater’s embeddedness within social-ecological systems at the global scale.