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Water Subsidies Alter Stream Systems

Proceedings of National Academy of Science of USA

Graduate Program in Environmental Science (GPES) Ph.D. student Melissa Rohde recently published an article titled "Groundwater dependence of riparian woodlands and the disrupting effect of anthropogenically altered streamflow" in the "Proceedings of the National Academy of Science of the United States of America," a high-impact journal. This study, funded by a grant from the National Science Foundation to Dr. John Stella's lab, focused on the sustainability of streamside forests in the context of groundwater decline in California and the state's Sustainable Groundwater Management Act.

In California, riparian (near stream) vegetation exhibits seasonal canopy stress responses to deeper groundwater, and this study indicated greater groundwater coupling along streams with natural flow regimes compared with human-altered streams. Water subsidies in altered stream systems reduce groundwater dependence of riparian woodlands, undermine their adaptations and resilience to natural hydrologic variation, and ultimately threaten their sustainability under dual threats of increased water demand and a changing climate.

The article and the larger research project have been featured in Inside Climate News, a leading news site for decision-makers and the public that reports on climate change, energy, and the environment. In addition, Rohde's work on sustainable groundwater has been featured in High Country News, an influential magazine about environmental issues in the western United States. Other outlets that have featured the paper are Tree Hugger, a sustainability news site and The Nature Conservancy's Groundwater Resource Hub.