“…The first we termed science and systems knowledge, which is based on water's unique scientific properties and its significance for living systems, including the water cycle and water's ability to transport dissolved and solid materials. This category encompasses ecosystem needs and flows, with five definitions [22,28,30,31,35] mentioning the role of water in life and one explicitly advocating for knowledge of interconnected aspects like "air, water, and/or biodiversity" [22] (p. 7). In addition, six definitions address hydrological processes, cycles and functions [7,18,28,31,33,38], but only three specify that water literacy includes knowledge at the level of water's chemical and physical properties [27,31,40].…”