The Supreme Court’s decision last year that rivers flowing only in response to weather events, known as ephemeral streams, are not protected under the Clean Water Act (CWA) has left many U.S. waterways vulnerable to pollution. This ruling, established in the case of Sackett v. Environmental Protection Agency (EPA), limits the scope of water bodies considered under the CWA to “relatively permanent, standing or continuously flowing bodies of water.” The Role of Ephemeral Streams in Water Systems New research published in the journal Science, led by Craig Brinkerhoff, a recent doctoral graduate from the University of Massachusetts Amherst, and co-authored by Yale University researchers, reveals that ephemeral streams contribute significantly to the water output of river systems across the United States. Ephemeral streams, which flow only during and after precipitation events and do not contain groundwater, were found to contribute 55% of the water at the mouth of regional river systems nationwide. This study highlights an east-west divide in the influence of ephemeral streams. In the arid regions west of the Mississippi River, such as the Black Rock Desert in Nevada and Humboldt County in California, ephemeral streams account for 94% of the water in river systems. Surprisingly, even in […]