A sweeping assessment has emerged indicating a vulnerability in the nation's waterway protections, as ephemeral streams—water bodies that flow primarily during rain events—are presently excluded from the safeguards of the Clean Water Act. A study spearheaded by the University of Massachusetts Ammerst's recent doctoral graduate Craig Brinkerhoff, and co-authored by Yale University peers, showcases the potential repercussions on waterways such as the Connecticut River. These findings, published in Science, reveal that 55% of water flowing out of regional rivers originates from such streams, according to UMass Amherst.
According to UMass Amherst's Colin Gleason, involved in the research, the Connecticut River's well-being is at stake, as pollutants dumped in undesignated areas, like dry gullies, could eventually contaminate the protected river. Gleason's remarks signify a stark dissonance between the river's stringent pollution regulations and the unattended ephemeral streams invariably leading into it. The study, leveraging hydrology models and field data, has pinpointed every ephemeral stream across the contiguous United States, gauging their contribution to river systems—an alarming 55% on average.
Disaggregation by region amplifies the concern, with ephemeral streams in the West, particularly in the Black Rock Desert, Nevada, and Humboldt County, California, contributing upwards of 94% to river flows. Craig Brinkerhoff's insights, shared with UMass Amherst, underscore the significant yet underrecognized impact of ephemeral streams not just in arid zones but even in the historically groundwater-rich Eastern states.
Gleason emphasized that on days reflecting average conditions, 59% of the water funneling into Long Island Sound from the Connecticut River is sourced from these now unregulated ephemeral streams—highlighting the pervasiveness of the issue at hand. However, the Supreme Court's narrow definition last summer, in the case of Sackett v. Environmental Protection Agency, of what constitutes a protected water body, practically omits ephemeral streams, despite the fact that these temporary waterways contribute to downstream flows which are subject to Clean Water Act regulations, raising the question of consistency in water quality management.
Doug Kysar of Yale Law School, a contributor to the study, pointed to the constitutional grounds for ephemeral streams' inclusion in the CWA, due to water pollution's inherently transboundary nature. Kysar's analysis suggests a possible shift of regulatory burdens to state and local governance, marking a reversal from the Clean Water Act's founding intent—addressing inadequacies in state and local water protection initiatives. These findings indicate far-reaching impacts of pollution that originate from ephemeral streams, often crossing state boundaries and adversely affecting downstream ecosystems and jurisdictions.
The study's message, as expressed by Brinkerhoff, hinges on the inextricable connectivity of water systems, heeding the urgency for comprehensive regulatory approaches. This discovery confronts previous assumptions about ephemeral streams, shedding light on the substantial volume of river water they furnish and by extension, the broad sweep of their environmental footprint.
