Due to multiple interacting factors, global water scarcity is projected to increase in the coming decades. As projected by the United Nations, the world's population will reach 9.8 billion by 2050 (U.N., 2017), which combined with income growth of Asian (led by China and India) and African countries, will lead to a 50% increase in demand for agricultural output mostly in water-stressed regions and developing countries (FAO, 2017). Moreover, as climate change is expected to increase variability in rainfall and temperatures (IPCC, 2014;Sheffield et al., 2012;Wasko & Nathan, 2019), reliable water sources such as groundwater (GW) are likely to represent an increasing share of global water consumption. Therefore, understanding the role of GW usage on the availability of both subsurface and surface water is of paramount importance for global food, water, and environmental security.Although it is common to conceptualize GW as causally linked to streamflow (SF), it remains challenging to identify where and how this interaction occurs (e.g., strength and direction). Interactions between GW and