The study analyzed riverbed temperatures to figure out how water flows underground around different structures in the river. By looking at temperature changes in the sediment, the researchers could see if the water was moving vertically or horizontally. They found that in natural systems, water flow is often not just up and down but also sideways. This new method helped them see that the water flow around certain river structures was not just up and down but also sideways, depending on where they were in the river and how high the water level was. This information can help us understand how water moves underground in rivers better.