Contribution of Anthropogenic and Climatic Drivers on the Variation of Surface Water Extent Across the Contiguous United States

Surface water resources are extremely vulnerable to climate variability and are severely affected by human activities. Future climate change and world population growth are expected to alter the extent of surface waters. This scenario highlights the need to assess how climate and human dynamics influence the variability of surface water resources, in order to support the definition of new management strategies that guarantee water conservation and an equitable access to freshwater resources. Here, we evaluate changes in surface water spatial extent over the period 1984-2020 across river basins of the contiguous United States (CONUS), as influenced by potential anthropogenic and climatic factors (population, irrigated area, precipitation, and temperature). We evaluate how the role of these potential factors has changed across river basins over time. We find that increasing irrigated areas and decreasing precipitation are typical of river basins showing the most significant loss of surface water extent.