Yellow River Runoff Declining, Threatening Water Supply and Ecosystems.
The study analyzed the runoff in the Yellow River upstream and main tributaries. It found that most of the runoff comes from precipitation, with some from groundwater and snow/ice melt. Runoff varies across different areas due to underlying surface conditions. Over time, there has been a decrease in runoff, especially during the flood season. The overall trend since 1986 has been a decline in runoff at the Lanzhou station.