Spatial Variation of Dissolved Oxygen in Lowland Rivers under Different Biogeochemical Processes

It was a research project to define the dissolved oxygen cycle in Lowland rivers, where dissolved oxygen deficit is one of the major impairments. In this research, we tried to document and demonstrate how biogeochemical processes along with physical hyporheic exchanges affect dissolved oxygen and result in variation of dissolved oxygen concentration in different spatial scale in a river ranging from millimeter in bottom sediment to meter in water column and further to kilometer in longitudinal direction. The formation of flocculent layer on top of bottom sediment act as a reactor in which oxygen is promptly consumed. A triple-layer numerical model, so-called VARTDO-3L, was prepared and introduced to simulate the processes.The model successfully applied to the Amite River in Louisiana.