Defining the term watershed to reflect modern uses and functions as inter- and intra-connected socio-hydrologic systems

Despite the many programs focused on watershed education, the watershed concept is poorly understood, which can lead to a number of wide-ranging consequences from poor watershed planning and policy to inaccurate scientific studies. We argue that the definition of the term watershed, and the images that accompany the definition, contribute to these misunderstandings. The definition has remained very much the same since it was first documented in Europe in the mid-18th century. However, watershed uses and functions have evolved considerably in the past three centuries, notably in the many ways water moves within and across traditionally-defined watershed boundaries. In this study, content analyses of the definitions of the term watershed from textbooks and online sources, and the accompanying images, highlight that watersheds are nearly universally defined as an area of land that drains to a point on a river. More than half the images that accompany these definitions depict forested landscapes or high mountain relief. While over one half of online images depict human activities or developed landscapes, few textbook images do. These incomplete definitions and idealized images do not reflect the diversity of landscapes and watershed functions. The narrow description can contribute to an individual’s disconnection to their own watershed. Furthermore, the description of watersheds as lumped areas, rather than inter- and intra-connected socio-hydrologic systems, misses a fundamental element of the watershed concept: that activities at every point in a watershed impact all points downstream and are impacted by activities at all points upstream. Thus, we propose a revised definition of a watershed that better captures this connectivity: a watershed defines the boundaries of a system of hydrologically connected people, places, and things.