Rivers are dendritic and hierarchically organized systems. Flowing from headwater to mouth, rivers regulate the transport and processing of water, energy, sediment, and nutrients, impacting humans and ecosystems. Understanding rivers, especially river discharge, as well as their dynamics and the controlling mechanisms, is critical to assess and manage the ecological and socioeconomic functionality of the entire river system in a changing world. However, such knowledge is often lacking due to the limited river monitoring systems in most places of the world. In this seminar, I will present a recent study in which we integrated primary satellite data and hydrologic models to comprehensively investigate the spatiotemporal distribution of daily river flow for ~2.9 million river reaches from 1984 to 2018 by creating the Global River Discharge Reanalysis (GRDR) dataset. Using GRDR, we found that river outlets were dominated by significant decreases in flow, whereas headwaters were 1.7 times more likely to have significantly increased flow than decreased. These changes result in a significant upstream shift in streamflow experienced by about 29% of the global land surface. We found the most changes in the smallest steams in our study: increases in erosion potential (approximately 5% increase in stream power), flood frequency (approximately 42% increase in 100-year floods), and likely nutrient dynamics (altered seasonal flow regimes).
https://osu.zoom.us/j/93543287034?pwd=CEtrhNBFcgn05Og8au61LDtNaiuESI.1
Passcode: 962250
