https://www.sciencedaily.com/releases/2022/09/220922124443.htm > Up to 80% of rivers and streams in the contiguous United States have been modified to some degree by human structures. Understanding the relationship between these modifications and ecological responses is key to enacting management policies that balance societal and ecological water needs. > Using measurements from more than 7,000 stream gauges, researchers developed a predictive model of hydrologic alteration and consequences for native fish biodiversity. They applied it to more than 2.6 million streams, creating a comprehensive dataset.