Morphodynamic processes sustaining anabranching river systems
Anabranching rivers are different from braided rivers in that their main channel branches are generally stable with the ability of holding high flows during storm events. They are separated by islands stabilized by vegetation and plants on them. In most regions of the world, anabranching rivers tend to have lower braiding intensities because relatively small number of channel branches assures that main channels have smaller width/depth ratio. Thus, channels of this nature have relatively high shear stress and less flow resistance, such that bed materials can be transported through these channels most efficiently. However, in the Qinghai-Tibet Plateau, the anabranching river reach in the Upper Yellow River does not follow this morphological rule as it has higher braiding intensity, while still remaining stable over time.
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Our research goal is to figure out the morphodynamic mechanisms that sustain this high-order anabranching river system. Using GIS and remoting sensing techniques, we are extracting morphological metrics of this reach for both channel branches and islands over five decades to find out their temporal trends of changes and link these trends to hydrological regimes and morphodynamic rules imbedded in these morphological trends.