Is Climate Change Infiltrating Your Backyard? The Impacts Of River Discharge

Rivers are important indicators of ecosystem health and the long-term effects of climate change. To better understand how climate change is affecting Ohio's rivers, Ohio State University undergraduate Melody Green, along with Drs. Devin Smith and Berry Lyons, have been studying the Grand River and Big Darby Creek. They will present their findings at GSA Connects 2024 in Anaheim, focusing on river discharge—a key measure of water volume flow.

Their research highlights how precipitation and extreme weather events impact river discharge, leading to fluctuations in water volume. These patterns are crucial for understanding the effects of climate change on rivers and their ecosystems.

As part of her senior research thesis, Green analyzed the discharge patterns of both rivers, which flow through northeast and central Ohio and have watersheds that are primarily composed of forested and agricultural ecosystems.

Using data from the past three decades, Green conducted statistical analyses on each river's discharge pattern to evaluate trends in discharge data. She implemented a Mann-Kendall Test—a statistical test that measures the strength of the relationship between two variables over time— to "determine whether or not there are seasonal trends" present in the data.

Green found that while overall discharge has increased from 1990 to 2021, the annual minimum discharge has been decreasing, indicating larger yearly discharge fluctuations with an overall increase in total discharge volume.

These findings suggest that long-term climate changes, such as higher levels of annual precipitation and more extreme weather events like storms and droughts, may be affecting the Grand and the Big Darby watersheds. Although a rise in annual discharge may signify an increase in precipitation and extreme weather events, Green's preliminary findings have shown that "there is not a significant correlation between precipitation and discharge in The Grand River."

Therefore, it is plausible that the variations in discharge are caused by a combination of global climate change and regional factors, such as urban and agricultural infrastructure. Whether these changes are being fueled by global climate change, regional land use changes, or a combination of both, Green asserts that the changes in discharge volume can have "a large impact on the surrounding community."

As a lifelong resident of Columbus, Ohio, Green has grown up with the Darby River in her backyard, so her research holds personal significance. She emphasizes the importance of researching and understanding how global climate change affects local climate. Green concludes, "regional research on rivers can contribute to larger scale understanding of the effects of climate change on surface water systems."