Front-fixing Model of Turbidity Currents at River Deltas in Lakes and Reservoirs

Sand-bed rivers form deltas when they reach standing bodies of water such as lakes and reservoirs. Most sand-bed rivers carry much more mud as wash load than they do sand as bed material load. Deltas typically form so that the sand falls out fluvially in a low-slope topset deposit and "avalanches" to form a much steeper prograding foreset deposit. The mud deposits out in a low-slope bottomset on the bed the lake or reservoir. Here the case of a sand-mud delta with co-evolving parts is treated numerically using a moving-boundary technique. Although the results reported here are preliminary, the simulated morphology shows a striking resemblance to e.g. the delta of the Colorado River in Lake Mead.